new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/README.mozilla
@@ -0,0 +1,9 @@
+This is a copy of the jemalloc source code. It is intended to be left pristine.
+Modifications to this code without coordinating with upstream are unacceptable,
+and will be reverted. Integration modifications should be made in memory/build
+whenever possible.
+
+The canonical repository for this source code is git://canonware.com/jemalloc.git.
+The information about the upstream repository and revision lives in upstream.info.
+In order to update the code, you can run the update.sh script located in
+the same directory.

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/COPYING
@@ -0,0 +1,27 @@
+Unless otherwise specified, files in the jemalloc source distribution are
+subject to the following license:
+--------------------------------------------------------------------------------
+Copyright (C) 2002-2012 Jason Evans <jasone@canonware.com>.
+All rights reserved.
+Copyright (C) 2007-2012 Mozilla Foundation.  All rights reserved.
+Copyright (C) 2009-2012 Facebook, Inc.  All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+1. Redistributions of source code must retain the above copyright notice(s),
+   this list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice(s),
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY EXPRESS
+OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
+EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+--------------------------------------------------------------------------------

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/ChangeLog
@@ -0,0 +1,339 @@
+Following are change highlights associated with official releases.  Important
+bug fixes are all mentioned, but internal enhancements are omitted here for
+brevity (even though they are more fun to write about).  Much more detail can be
+found in the git revision history:
+
+    http://www.canonware.com/cgi-bin/gitweb.cgi?p=jemalloc.git
+    git://canonware.com/jemalloc.git
+
+* 3.0.0 (May 11, 2012)
+
+  Although this version adds some major new features, the primary focus is on
+  internal code cleanup that facilitates maintainability and portability, most
+  of which is not reflected in the ChangeLog.  This is the first release to
+  incorporate substantial contributions from numerous other developers, and the
+  result is a more broadly useful allocator (see the git revision history for
+  contribution details).  Note that the license has been unified, thanks to
+  Facebook granting a license under the same terms as the other copyright
+  holders (see COPYING).
+
+  New features:
+  - Implement Valgrind support, redzones, and quarantine.
+  - Add support for additional platforms:
+    + FreeBSD
+    + Mac OS X Lion
+    + MinGW
+    + Windows (no support yet for replacing the system malloc)
+  - Add support for additional architectures:
+    + MIPS
+    + SH4
+    + Tilera
+  - Add support for cross compiling.
+  - Add nallocm(), which rounds a request size up to the nearest size class
+    without actually allocating.
+  - Implement aligned_alloc() (blame C11).
+  - Add the "thread.tcache.enabled" mallctl.
+  - Add the "opt.prof_final" mallctl.
+  - Update pprof (from gperftools 2.0).
+  - Add the --with-mangling option.
+  - Add the --disable-experimental option.
+  - Add the --disable-munmap option, and make it the default on Linux.
+  - Add the --enable-mremap option, which disables use of mremap(2) by default.
+
+  Incompatible changes:
+  - Enable stats by default.
+  - Enable fill by default.
+  - Disable lazy locking by default.
+  - Rename the "tcache.flush" mallctl to "thread.tcache.flush".
+  - Rename the "arenas.pagesize" mallctl to "arenas.page".
+  - Change the "opt.lg_prof_sample" default from 0 to 19 (1 B to 512 KiB).
+  - Change the "opt.prof_accum" default from true to false.
+
+  Removed features:
+  - Remove the swap feature, including the "config.swap", "swap.avail",
+    "swap.prezeroed", "swap.nfds", and "swap.fds" mallctls.
+  - Remove highruns statistics, including the
+    "stats.arenas.<i>.bins.<j>.highruns" and
+    "stats.arenas.<i>.lruns.<j>.highruns" mallctls.
+  - As part of small size class refactoring, remove the "opt.lg_[qc]space_max",
+    "arenas.cacheline", "arenas.subpage", "arenas.[tqcs]space_{min,max}", and
+    "arenas.[tqcs]bins" mallctls.
+  - Remove the "arenas.chunksize" mallctl.
+  - Remove the "opt.lg_prof_tcmax" option.
+  - Remove the "opt.lg_prof_bt_max" option.
+  - Remove the "opt.lg_tcache_gc_sweep" option.
+  - Remove the --disable-tiny option, including the "config.tiny" mallctl.
+  - Remove the --enable-dynamic-page-shift configure option.
+  - Remove the --enable-sysv configure option.
+
+  Bug fixes:
+  - Fix a statistics-related bug in the "thread.arena" mallctl that could cause
+    invalid statistics and crashes.
+  - Work around TLS deallocation via free() on Linux.  This bug could cause
+    write-after-free memory corruption.
+  - Fix a potential deadlock that could occur during interval- and
+    growth-triggered heap profile dumps.
+  - Fix large calloc() zeroing bugs due to dropping chunk map unzeroed flags.
+  - Fix chunk_alloc_dss() to stop claiming memory is zeroed.  This bug could
+    cause memory corruption and crashes with --enable-dss specified.
+  - Fix fork-related bugs that could cause deadlock in children between fork
+    and exec.
+  - Fix malloc_stats_print() to honor 'b' and 'l' in the opts parameter.
+  - Fix realloc(p, 0) to act like free(p).
+  - Do not enforce minimum alignment in memalign().
+  - Check for NULL pointer in malloc_usable_size().
+  - Fix an off-by-one heap profile statistics bug that could be observed in
+    interval- and growth-triggered heap profiles.
+  - Fix the "epoch" mallctl to update cached stats even if the passed in epoch
+    is 0.
+  - Fix bin->runcur management to fix a layout policy bug.  This bug did not
+    affect correctness.
+  - Fix a bug in choose_arena_hard() that potentially caused more arenas to be
+    initialized than necessary.
+  - Add missing "opt.lg_tcache_max" mallctl implementation.
+  - Use glibc allocator hooks to make mixed allocator usage less likely.
+  - Fix build issues for --disable-tcache.
+  - Don't mangle pthread_create() when --with-private-namespace is specified.
+
+* 2.2.5 (November 14, 2011)
+
+  Bug fixes:
+  - Fix huge_ralloc() race when using mremap(2).  This is a serious bug that
+    could cause memory corruption and/or crashes.
+  - Fix huge_ralloc() to maintain chunk statistics.
+  - Fix malloc_stats_print(..., "a") output.
+
+* 2.2.4 (November 5, 2011)
+
+  Bug fixes:
+  - Initialize arenas_tsd before using it.  This bug existed for 2.2.[0-3], as
+    well as for --disable-tls builds in earlier releases.
+  - Do not assume a 4 KiB page size in test/rallocm.c.
+
+* 2.2.3 (August 31, 2011)
+
+  This version fixes numerous bugs related to heap profiling.
+
+  Bug fixes:
+  - Fix a prof-related race condition.  This bug could cause memory corruption,
+    but only occurred in non-default configurations (prof_accum:false).
+  - Fix off-by-one backtracing issues (make sure that prof_alloc_prep() is
+    excluded from backtraces).
+  - Fix a prof-related bug in realloc() (only triggered by OOM errors).
+  - Fix prof-related bugs in allocm() and rallocm().
+  - Fix prof_tdata_cleanup() for --disable-tls builds.
+  - Fix a relative include path, to fix objdir builds.
+
+* 2.2.2 (July 30, 2011)
+
+  Bug fixes:
+  - Fix a build error for --disable-tcache.
+  - Fix assertions in arena_purge() (for real this time).
+  - Add the --with-private-namespace option.  This is a workaround for symbol
+    conflicts that can inadvertently arise when using static libraries.
+
+* 2.2.1 (March 30, 2011)
+
+  Bug fixes:
+  - Implement atomic operations for x86/x64.  This fixes compilation failures
+    for versions of gcc that are still in wide use.
+  - Fix an assertion in arena_purge().
+
+* 2.2.0 (March 22, 2011)
+
+  This version incorporates several improvements to algorithms and data
+  structures that tend to reduce fragmentation and increase speed.
+
+  New features:
+  - Add the "stats.cactive" mallctl.
+  - Update pprof (from google-perftools 1.7).
+  - Improve backtracing-related configuration logic, and add the
+    --disable-prof-libgcc option.
+
+  Bug fixes:
+  - Change default symbol visibility from "internal", to "hidden", which
+    decreases the overhead of library-internal function calls.
+  - Fix symbol visibility so that it is also set on OS X.
+  - Fix a build dependency regression caused by the introduction of the .pic.o
+    suffix for PIC object files.
+  - Add missing checks for mutex initialization failures.
+  - Don't use libgcc-based backtracing except on x64, where it is known to work.
+  - Fix deadlocks on OS X that were due to memory allocation in
+    pthread_mutex_lock().
+  - Heap profiling-specific fixes:
+    + Fix memory corruption due to integer overflow in small region index
+      computation, when using a small enough sample interval that profiling
+      context pointers are stored in small run headers.
+    + Fix a bootstrap ordering bug that only occurred with TLS disabled.
+    + Fix a rallocm() rsize bug.
+    + Fix error detection bugs for aligned memory allocation.
+
+* 2.1.3 (March 14, 2011)
+
+  Bug fixes:
+  - Fix a cpp logic regression (due to the "thread.{de,}allocatedp" mallctl fix
+    for OS X in 2.1.2).
+  - Fix a "thread.arena" mallctl bug.
+  - Fix a thread cache stats merging bug.
+
+* 2.1.2 (March 2, 2011)
+
+  Bug fixes:
+  - Fix "thread.{de,}allocatedp" mallctl for OS X.
+  - Add missing jemalloc.a to build system.
+
+* 2.1.1 (January 31, 2011)
+
+  Bug fixes:
+  - Fix aligned huge reallocation (affected allocm()).
+  - Fix the ALLOCM_LG_ALIGN macro definition.
+  - Fix a heap dumping deadlock.
+  - Fix a "thread.arena" mallctl bug.
+
+* 2.1.0 (December 3, 2010)
+
+  This version incorporates some optimizations that can't quite be considered
+  bug fixes.
+
+  New features:
+  - Use Linux's mremap(2) for huge object reallocation when possible.
+  - Avoid locking in mallctl*() when possible.
+  - Add the "thread.[de]allocatedp" mallctl's.
+  - Convert the manual page source from roff to DocBook, and generate both roff
+    and HTML manuals.
+
+  Bug fixes:
+  - Fix a crash due to incorrect bootstrap ordering.  This only impacted
+    --enable-debug --enable-dss configurations.
+  - Fix a minor statistics bug for mallctl("swap.avail", ...).
+
+* 2.0.1 (October 29, 2010)
+
+  Bug fixes:
+  - Fix a race condition in heap profiling that could cause undefined behavior
+    if "opt.prof_accum" were disabled.
+  - Add missing mutex unlocks for some OOM error paths in the heap profiling
+    code.
+  - Fix a compilation error for non-C99 builds.
+
+* 2.0.0 (October 24, 2010)
+
+  This version focuses on the experimental *allocm() API, and on improved
+  run-time configuration/introspection.  Nonetheless, numerous performance
+  improvements are also included.
+
+  New features:
+  - Implement the experimental {,r,s,d}allocm() API, which provides a superset
+    of the functionality available via malloc(), calloc(), posix_memalign(),
+    realloc(), malloc_usable_size(), and free().  These functions can be used to
+    allocate/reallocate aligned zeroed memory, ask for optional extra memory
+    during reallocation, prevent object movement during reallocation, etc.
+  - Replace JEMALLOC_OPTIONS/JEMALLOC_PROF_PREFIX with MALLOC_CONF, which is
+    more human-readable, and more flexible.  For example:
+      JEMALLOC_OPTIONS=AJP
+    is now:
+      MALLOC_CONF=abort:true,fill:true,stats_print:true
+  - Port to Apple OS X.  Sponsored by Mozilla.
+  - Make it possible for the application to control thread-->arena mappings via
+    the "thread.arena" mallctl.
+  - Add compile-time support for all TLS-related functionality via pthreads TSD.
+    This is mainly of interest for OS X, which does not support TLS, but has a
+    TSD implementation with similar performance.
+  - Override memalign() and valloc() if they are provided by the system.
+  - Add the "arenas.purge" mallctl, which can be used to synchronously purge all
+    dirty unused pages.
+  - Make cumulative heap profiling data optional, so that it is possible to
+    limit the amount of memory consumed by heap profiling data structures.
+  - Add per thread allocation counters that can be accessed via the
+    "thread.allocated" and "thread.deallocated" mallctls.
+
+  Incompatible changes:
+  - Remove JEMALLOC_OPTIONS and malloc_options (see MALLOC_CONF above).
+  - Increase default backtrace depth from 4 to 128 for heap profiling.
+  - Disable interval-based profile dumps by default.
+
+  Bug fixes:
+  - Remove bad assertions in fork handler functions.  These assertions could
+    cause aborts for some combinations of configure settings.
+  - Fix strerror_r() usage to deal with non-standard semantics in GNU libc.
+  - Fix leak context reporting.  This bug tended to cause the number of contexts
+    to be underreported (though the reported number of objects and bytes were
+    correct).
+  - Fix a realloc() bug for large in-place growing reallocation.  This bug could
+    cause memory corruption, but it was hard to trigger.
+  - Fix an allocation bug for small allocations that could be triggered if
+    multiple threads raced to create a new run of backing pages.
+  - Enhance the heap profiler to trigger samples based on usable size, rather
+    than request size.
+  - Fix a heap profiling bug due to sometimes losing track of requested object
+    size for sampled objects.
+
+* 1.0.3 (August 12, 2010)
+
+  Bug fixes:
+  - Fix the libunwind-based implementation of stack backtracing (used for heap
+    profiling).  This bug could cause zero-length backtraces to be reported.
+  - Add a missing mutex unlock in library initialization code.  If multiple
+    threads raced to initialize malloc, some of them could end up permanently
+    blocked.
+
+* 1.0.2 (May 11, 2010)
+
+  Bug fixes:
+  - Fix junk filling of large objects, which could cause memory corruption.
+  - Add MAP_NORESERVE support for chunk mapping, because otherwise virtual
+    memory limits could cause swap file configuration to fail.  Contributed by
+    Jordan DeLong.
+
+* 1.0.1 (April 14, 2010)
+
+  Bug fixes:
+  - Fix compilation when --enable-fill is specified.
+  - Fix threads-related profiling bugs that affected accuracy and caused memory
+    to be leaked during thread exit.
+  - Fix dirty page purging race conditions that could cause crashes.
+  - Fix crash in tcache flushing code during thread destruction.
+
+* 1.0.0 (April 11, 2010)
+
+  This release focuses on speed and run-time introspection.  Numerous
+  algorithmic improvements make this release substantially faster than its
+  predecessors.
+
+  New features:
+  - Implement autoconf-based configuration system.
+  - Add mallctl*(), for the purposes of introspection and run-time
+    configuration.
+  - Make it possible for the application to manually flush a thread's cache, via
+    the "tcache.flush" mallctl.
+  - Base maximum dirty page count on proportion of active memory.
+  - Compute various addtional run-time statistics, including per size class
+    statistics for large objects.
+  - Expose malloc_stats_print(), which can be called repeatedly by the
+    application.
+  - Simplify the malloc_message() signature to only take one string argument,
+    and incorporate an opaque data pointer argument for use by the application
+    in combination with malloc_stats_print().
+  - Add support for allocation backed by one or more swap files, and allow the
+    application to disable over-commit if swap files are in use.
+  - Implement allocation profiling and leak checking.
+
+  Removed features:
+  - Remove the dynamic arena rebalancing code, since thread-specific caching
+    reduces its utility.
+
+  Bug fixes:
+  - Modify chunk allocation to work when address space layout randomization
+    (ASLR) is in use.
+  - Fix thread cleanup bugs related to TLS destruction.
+  - Handle 0-size allocation requests in posix_memalign().
+  - Fix a chunk leak.  The leaked chunks were never touched, so this impacted
+    virtual memory usage, but not physical memory usage.
+
+* linux_2008082[78]a (August 27/28, 2008)
+
+  These snapshot releases are the simple result of incorporating Linux-specific
+  support into the FreeBSD malloc sources.
+
+--------------------------------------------------------------------------------
+vim:filetype=text:textwidth=80

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/INSTALL
@@ -0,0 +1,278 @@
+Building and installing jemalloc can be as simple as typing the following while
+in the root directory of the source tree:
+
+    ./configure
+    make
+    make install
+
+=== Advanced configuration =====================================================
+
+The 'configure' script supports numerous options that allow control of which
+functionality is enabled, where jemalloc is installed, etc.  Optionally, pass
+any of the following arguments (not a definitive list) to 'configure':
+
+--help
+    Print a definitive list of options.
+
+--prefix=<install-root-dir>
+    Set the base directory in which to install.  For example:
+
+        ./configure --prefix=/usr/local
+
+    will cause files to be installed into /usr/local/include, /usr/local/lib,
+    and /usr/local/man.
+
+--with-rpath=<colon-separated-rpath>
+    Embed one or more library paths, so that libjemalloc can find the libraries
+    it is linked to.  This works only on ELF-based systems.
+
+--with-mangling=<map>
+    Mangle public symbols specified in <map> which is a comma-separated list of
+    name:mangled pairs.
+
+    For example, to use ld's --wrap option as an alternative method for
+    overriding libc's malloc implementation, specify something like:
+
+      --with-mangling=malloc:__wrap_malloc,free:__wrap_free[...]
+
+    Note that mangling happens prior to application of the prefix specified by
+    --with-jemalloc-prefix, and mangled symbols are then ignored when applying
+    the prefix.
+
+--with-jemalloc-prefix=<prefix>
+    Prefix all public APIs with <prefix>.  For example, if <prefix> is
+    "prefix_", API changes like the following occur:
+
+      malloc()         --> prefix_malloc()
+      malloc_conf      --> prefix_malloc_conf
+      /etc/malloc.conf --> /etc/prefix_malloc.conf
+      MALLOC_CONF      --> PREFIX_MALLOC_CONF
+
+    This makes it possible to use jemalloc at the same time as the system
+    allocator, or even to use multiple copies of jemalloc simultaneously.
+
+    By default, the prefix is "", except on OS X, where it is "je_".  On OS X,
+    jemalloc overlays the default malloc zone, but makes no attempt to actually
+    replace the "malloc", "calloc", etc. symbols.
+
+--with-private-namespace=<prefix>
+    Prefix all library-private APIs with <prefix>.  For shared libraries,
+    symbol visibility mechanisms prevent these symbols from being exported, but
+    for static libraries, naming collisions are a real possibility.  By
+    default, the prefix is "" (empty string).
+
+--with-install-suffix=<suffix>
+    Append <suffix> to the base name of all installed files, such that multiple
+    versions of jemalloc can coexist in the same installation directory.  For
+    example, libjemalloc.so.0 becomes libjemalloc<suffix>.so.0.
+
+--enable-cc-silence
+    Enable code that silences non-useful compiler warnings.  This is helpful
+    when trying to tell serious warnings from those due to compiler
+    limitations, but it potentially incurs a performance penalty.
+
+--enable-debug
+    Enable assertions and validation code.  This incurs a substantial
+    performance hit, but is very useful during application development.
+
+--disable-stats
+    Disable statistics gathering functionality.  See the "opt.stats_print"
+    option documentation for usage details.
+
+--enable-prof
+    Enable heap profiling and leak detection functionality.  See the "opt.prof"
+    option documentation for usage details.  When enabled, there are several
+    approaches to backtracing, and the configure script chooses the first one
+    in the following list that appears to function correctly:
+
+    + libunwind      (requires --enable-prof-libunwind)
+    + libgcc         (unless --disable-prof-libgcc)
+    + gcc intrinsics (unless --disable-prof-gcc)
+
+--enable-prof-libunwind
+    Use the libunwind library (http://www.nongnu.org/libunwind/) for stack
+    backtracing.
+
+--disable-prof-libgcc
+    Disable the use of libgcc's backtracing functionality.
+
+--disable-prof-gcc
+    Disable the use of gcc intrinsics for backtracing.
+
+--with-static-libunwind=<libunwind.a>
+    Statically link against the specified libunwind.a rather than dynamically
+    linking with -lunwind.
+
+--disable-tcache
+    Disable thread-specific caches for small objects.  Objects are cached and
+    released in bulk, thus reducing the total number of mutex operations.  See
+    the "opt.tcache" option for usage details.
+
+--enable-mremap
+    Enable huge realloc() via mremap(2).  mremap() is disabled by default
+    because the flavor used is specific to Linux, which has a quirk in its
+    virtual memory allocation algorithm that causes semi-permanent VM map holes
+    under normal jemalloc operation.
+
+--disable-munmap
+    Disable virtual memory deallocation via munmap(2); instead keep track of
+    the virtual memory for later use.  munmap() is disabled by default (i.e.
+    --disable-munmap is implied) on Linux, which has a quirk in its virtual
+    memory allocation algorithm that causes semi-permanent VM map holes under
+    normal jemalloc operation.
+
+--enable-dss
+    Enable support for page allocation/deallocation via sbrk(2), in addition to
+    mmap(2).
+
+--disable-fill
+    Disable support for junk/zero filling of memory, quarantine, and redzones.
+    See the "opt.junk", "opt.zero", "opt.quarantine", and "opt.redzone" option
+    documentation for usage details.
+
+--disable-valgrind
+    Disable support for Valgrind.
+
+--disable-experimental
+    Disable support for the experimental API (*allocm()).
+
+--enable-utrace
+    Enable utrace(2)-based allocation tracing.  This feature is not broadly
+    portable (FreeBSD has it, but Linux and OS X do not).
+
+--enable-xmalloc
+    Enable support for optional immediate termination due to out-of-memory
+    errors, as is commonly implemented by "xmalloc" wrapper function for malloc.
+    See the "opt.xmalloc" option documentation for usage details.
+
+--enable-lazy-lock
+    Enable code that wraps pthread_create() to detect when an application
+    switches from single-threaded to multi-threaded mode, so that it can avoid
+    mutex locking/unlocking operations while in single-threaded mode.  In
+    practice, this feature usually has little impact on performance unless
+    thread-specific caching is disabled.
+
+--disable-tls
+    Disable thread-local storage (TLS), which allows for fast access to
+    thread-local variables via the __thread keyword.  If TLS is available,
+    jemalloc uses it for several purposes.
+
+--with-xslroot=<path>
+    Specify where to find DocBook XSL stylesheets when building the
+    documentation.
+
+The following environment variables (not a definitive list) impact configure's
+behavior:
+
+CFLAGS="?"
+    Pass these flags to the compiler.  You probably shouldn't define this unless
+    you know what you are doing.  (Use EXTRA_CFLAGS instead.)
+
+EXTRA_CFLAGS="?"
+    Append these flags to CFLAGS.  This makes it possible to add flags such as
+    -Werror, while allowing the configure script to determine what other flags
+    are appropriate for the specified configuration.
+
+    The configure script specifically checks whether an optimization flag (-O*)
+    is specified in EXTRA_CFLAGS, and refrains from specifying an optimization
+    level if it finds that one has already been specified.
+
+CPPFLAGS="?"
+    Pass these flags to the C preprocessor.  Note that CFLAGS is not passed to
+    'cpp' when 'configure' is looking for include files, so you must use
+    CPPFLAGS instead if you need to help 'configure' find header files.
+
+LD_LIBRARY_PATH="?"
+    'ld' uses this colon-separated list to find libraries.
+
+LDFLAGS="?"
+    Pass these flags when linking.
+
+PATH="?"
+    'configure' uses this to find programs.
+
+=== Advanced compilation =======================================================
+
+To build only parts of jemalloc, use the following targets:
+
+    build_lib_shared
+    build_lib_static
+    build_lib
+    build_doc_html
+    build_doc_man
+    build_doc
+
+To install only parts of jemalloc, use the following targets:
+
+    install_bin
+    install_include
+    install_lib_shared
+    install_lib_static
+    install_lib
+    install_doc_html
+    install_doc_man
+    install_doc
+
+To clean up build results to varying degrees, use the following make targets:
+
+    clean
+    distclean
+    relclean
+
+=== Advanced installation ======================================================
+
+Optionally, define make variables when invoking make, including (not
+exclusively):
+
+INCLUDEDIR="?"
+    Use this as the installation prefix for header files.
+
+LIBDIR="?"
+    Use this as the installation prefix for libraries.
+
+MANDIR="?"
+    Use this as the installation prefix for man pages.
+
+DESTDIR="?"
+    Prepend DESTDIR to INCLUDEDIR, LIBDIR, DATADIR, and MANDIR.  This is useful
+    when installing to a different path than was specified via --prefix.
+
+CC="?"
+    Use this to invoke the C compiler.
+
+CFLAGS="?"
+    Pass these flags to the compiler.
+
+CPPFLAGS="?"
+    Pass these flags to the C preprocessor.
+
+LDFLAGS="?"
+    Pass these flags when linking.
+
+PATH="?"
+    Use this to search for programs used during configuration and building.
+
+=== Development ================================================================
+
+If you intend to make non-trivial changes to jemalloc, use the 'autogen.sh'
+script rather than 'configure'.  This re-generates 'configure', enables
+configuration dependency rules, and enables re-generation of automatically
+generated source files.
+
+The build system supports using an object directory separate from the source
+tree.  For example, you can create an 'obj' directory, and from within that
+directory, issue configuration and build commands:
+
+    autoconf
+    mkdir obj
+    cd obj
+    ../configure --enable-autogen
+    make
+
+=== Documentation ==============================================================
+
+The manual page is generated in both html and roff formats.  Any web browser
+can be used to view the html manual.  The roff manual page can be formatted
+prior to installation via the following command:
+
+    nroff -man -t doc/jemalloc.3

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/Makefile.in
@@ -0,0 +1,323 @@
+# Clear out all vpaths, then set just one (default vpath) for the main build
+# directory.
+vpath
+vpath % .
+
+# Clear the default suffixes, so that built-in rules are not used.
+.SUFFIXES :
+
+SHELL := /bin/sh
+
+CC := @CC@
+
+# Configuration parameters.
+DESTDIR =
+BINDIR := $(DESTDIR)@BINDIR@
+INCLUDEDIR := $(DESTDIR)@INCLUDEDIR@
+LIBDIR := $(DESTDIR)@LIBDIR@
+DATADIR := $(DESTDIR)@DATADIR@
+MANDIR := $(DESTDIR)@MANDIR@
+srcroot := @srcroot@
+objroot := @objroot@
+abs_srcroot := @abs_srcroot@
+abs_objroot := @abs_objroot@
+
+# Build parameters.
+CPPFLAGS := @CPPFLAGS@ -I$(srcroot)include -I$(objroot)include
+CFLAGS := @CFLAGS@
+LDFLAGS := @LDFLAGS@
+EXTRA_LDFLAGS := @EXTRA_LDFLAGS@
+LIBS := @LIBS@
+RPATH_EXTRA := @RPATH_EXTRA@
+SO := @so@
+IMPORTLIB := @importlib@
+O := @o@
+A := @a@
+EXE := @exe@
+LIBPREFIX := @libprefix@
+REV := @rev@
+install_suffix := @install_suffix@
+ABI := @abi@
+XSLTPROC := @XSLTPROC@
+AUTOCONF := @AUTOCONF@
+_RPATH = @RPATH@
+RPATH = $(if $(1),$(call _RPATH,$(1)))
+cfghdrs_in := @cfghdrs_in@
+cfghdrs_out := @cfghdrs_out@
+cfgoutputs_in := @cfgoutputs_in@
+cfgoutputs_out := @cfgoutputs_out@
+enable_autogen := @enable_autogen@
+enable_experimental := @enable_experimental@
+DSO_LDFLAGS = @DSO_LDFLAGS@
+SOREV = @SOREV@
+PIC_CFLAGS = @PIC_CFLAGS@
+CTARGET = @CTARGET@
+LDTARGET = @LDTARGET@
+MKLIB = @MKLIB@
+CC_MM = @CC_MM@
+
+ifeq (macho, $(ABI))
+TEST_LIBRARY_PATH := DYLD_FALLBACK_LIBRARY_PATH="$(objroot)lib"
+else
+ifeq (pecoff, $(ABI))
+TEST_LIBRARY_PATH := PATH="$(PATH):$(objroot)lib"
+else
+TEST_LIBRARY_PATH :=
+endif
+endif
+
+LIBJEMALLOC := $(LIBPREFIX)jemalloc$(install_suffix)
+
+# Lists of files.
+BINS := $(srcroot)bin/pprof $(objroot)bin/jemalloc.sh
+CHDRS := $(objroot)include/jemalloc/jemalloc$(install_suffix).h \
+	$(objroot)include/jemalloc/jemalloc_defs$(install_suffix).h
+CSRCS := $(srcroot)src/jemalloc.c $(srcroot)src/arena.c $(srcroot)src/atomic.c \
+	$(srcroot)src/base.c $(srcroot)src/bitmap.c $(srcroot)src/chunk.c \
+	$(srcroot)src/chunk_dss.c $(srcroot)src/chunk_mmap.c \
+	$(srcroot)src/ckh.c $(srcroot)src/ctl.c $(srcroot)src/extent.c \
+	$(srcroot)src/hash.c $(srcroot)src/huge.c $(srcroot)src/mb.c \
+	$(srcroot)src/mutex.c $(srcroot)src/prof.c $(srcroot)src/quarantine.c \
+	$(srcroot)src/rtree.c $(srcroot)src/stats.c $(srcroot)src/tcache.c \
+	$(srcroot)src/util.c $(srcroot)src/tsd.c
+ifeq (macho, $(ABI))
+CSRCS += $(srcroot)src/zone.c
+endif
+ifeq ($(IMPORTLIB),$(SO))
+STATIC_LIBS := $(objroot)lib/$(LIBJEMALLOC).$(A)
+endif
+ifdef PIC_CFLAGS
+STATIC_LIBS += $(objroot)lib/$(LIBJEMALLOC)_pic.$(A)
+else
+STATIC_LIBS += $(objroot)lib/$(LIBJEMALLOC)_s.$(A)
+endif
+DSOS := $(objroot)lib/$(LIBJEMALLOC).$(SOREV)
+ifneq ($(SOREV),$(SO))
+DSOS += $(objroot)lib/$(LIBJEMALLOC).$(SO)
+endif
+MAN3 := $(objroot)doc/jemalloc$(install_suffix).3
+DOCS_XML := $(objroot)doc/jemalloc$(install_suffix).xml
+DOCS_HTML := $(DOCS_XML:$(objroot)%.xml=$(srcroot)%.html)
+DOCS_MAN3 := $(DOCS_XML:$(objroot)%.xml=$(srcroot)%.3)
+DOCS := $(DOCS_HTML) $(DOCS_MAN3)
+CTESTS := $(srcroot)test/aligned_alloc.c $(srcroot)test/allocated.c \
+	$(srcroot)test/bitmap.c $(srcroot)test/mremap.c \
+	$(srcroot)test/posix_memalign.c $(srcroot)test/thread_arena.c \
+	$(srcroot)test/thread_tcache_enabled.c
+ifeq ($(enable_experimental), 1)
+CTESTS += $(srcroot)test/allocm.c $(srcroot)test/rallocm.c
+endif
+
+COBJS := $(CSRCS:$(srcroot)%.c=$(objroot)%.$(O))
+CPICOBJS := $(CSRCS:$(srcroot)%.c=$(objroot)%.pic.$(O))
+CTESTOBJS := $(CTESTS:$(srcroot)%.c=$(objroot)%.$(O))
+
+.PHONY: all dist doc_html doc_man doc
+.PHONY: install_bin install_include install_lib
+.PHONY: install_html install_man install_doc install
+.PHONY: tests check clean distclean relclean
+
+.SECONDARY : $(CTESTOBJS)
+
+# Default target.
+all: build
+
+dist: build_doc
+
+$(srcroot)doc/%.html : $(objroot)doc/%.xml $(srcroot)doc/stylesheet.xsl $(objroot)doc/html.xsl
+	$(XSLTPROC) -o $@ $(objroot)doc/html.xsl $<
+
+$(srcroot)doc/%.3 : $(objroot)doc/%.xml $(srcroot)doc/stylesheet.xsl $(objroot)doc/manpages.xsl
+	$(XSLTPROC) -o $@ $(objroot)doc/manpages.xsl $<
+
+build_doc_html: $(DOCS_HTML)
+build_doc_man: $(DOCS_MAN3)
+build_doc: $(DOCS)
+
+#
+# Include generated dependency files.
+#
+ifdef CC_MM
+-include $(COBJS:%.$(O)=%.d)
+-include $(CPICOBJS:%.$(O)=%.d)
+-include $(CTESTOBJS:%.$(O)=%.d)
+endif
+
+$(COBJS): $(objroot)src/%.$(O): $(srcroot)src/%.c
+$(CPICOBJS): $(objroot)src/%.pic.$(O): $(srcroot)src/%.c
+$(CPICOBJS): CFLAGS += $(PIC_CFLAGS)
+$(CTESTOBJS): $(objroot)test/%.$(O): $(srcroot)test/%.c
+$(CTESTOBJS): CPPFLAGS += -I$(objroot)test
+ifneq ($(IMPORTLIB),$(SO))
+$(COBJS): CPPFLAGS += -DDLLEXPORT
+endif
+
+ifndef CC_MM
+# Dependencies
+HEADER_DIRS = $(srcroot)include/jemalloc/internal \
+	$(objroot)include/jemalloc $(objroot)include/jemalloc/internal
+HEADERS = $(wildcard $(foreach dir,$(HEADER_DIRS),$(dir)/*.h))
+$(COBJS) $(CPICOBJS) $(CTESTOBJS): $(HEADERS)
+$(CTESTOBJS): $(objroot)test/jemalloc_test.h
+endif
+
+$(COBJS) $(CPICOBJS) $(CTESTOBJS): %.$(O):
+	@mkdir -p $(@D)
+	$(CC) $(CFLAGS) -c $(CPPFLAGS) $(CTARGET) $<
+ifdef CC_MM
+	@$(CC) -MM $(CPPFLAGS) -MT $@ -o $(@:%.$(O)=%.d) $<
+endif
+
+ifneq ($(SOREV),$(SO))
+%.$(SO) : %.$(SOREV)
+	@mkdir -p $(@D)
+	ln -sf $(<F) $@
+endif
+
+$(objroot)lib/$(LIBJEMALLOC).$(SOREV) : $(if $(PIC_CFLAGS),$(CPICOBJS),$(COBJS))
+	@mkdir -p $(@D)
+	$(CC) $(DSO_LDFLAGS) $(call RPATH,$(RPATH_EXTRA)) $(LDTARGET) $+ $(LDFLAGS) $(LIBS) $(EXTRA_LDFLAGS)
+
+$(objroot)lib/$(LIBJEMALLOC)_pic.$(A) : $(CPICOBJS)
+$(objroot)lib/$(LIBJEMALLOC).$(A) : $(COBJS)
+$(objroot)lib/$(LIBJEMALLOC)_s.$(A) : $(COBJS)
+
+$(STATIC_LIBS):
+	@mkdir -p $(@D)
+	$(MKLIB) $+
+
+$(objroot)test/bitmap$(EXE): $(objroot)src/bitmap.$(O)
+
+$(objroot)test/%$(EXE): $(objroot)test/%.$(O) $(objroot)src/util.$(O) $(DSOS)
+	@mkdir -p $(@D)
+	$(CC) $(LDTARGET) $(filter %.$(O),$^) $(call RPATH,$(objroot)lib) $(objroot)lib/$(LIBJEMALLOC).$(IMPORTLIB) $(filter -lpthread,$(LIBS)) $(EXTRA_LDFLAGS)
+
+build_lib_shared: $(DSOS)
+build_lib_static: $(STATIC_LIBS)
+build: build_lib_shared build_lib_static
+
+install_bin:
+	install -d $(BINDIR)
+	@for b in $(BINS); do \
+	echo "install -m 755 $$b $(BINDIR)"; \
+	install -m 755 $$b $(BINDIR); \
+done
+
+install_include:
+	install -d $(INCLUDEDIR)/jemalloc
+	@for h in $(CHDRS); do \
+	echo "install -m 644 $$h $(INCLUDEDIR)/jemalloc"; \
+	install -m 644 $$h $(INCLUDEDIR)/jemalloc; \
+done
+
+install_lib_shared: $(DSOS)
+	install -d $(LIBDIR)
+	install -m 755 $(objroot)lib/$(LIBJEMALLOC).$(SOREV) $(LIBDIR)
+ifneq ($(SOREV),$(SO))
+	ln -sf $(LIBJEMALLOC).$(SOREV) $(LIBDIR)/$(LIBJEMALLOC).$(SO)
+endif
+
+install_lib_static: $(STATIC_LIBS)
+	install -d $(LIBDIR)
+	@for l in $(STATIC_LIBS); do \
+	echo "install -m 755 $$l $(LIBDIR)"; \
+	install -m 755 $$l $(LIBDIR); \
+done
+
+install_lib: install_lib_shared install_lib_static
+
+install_doc_html:
+	install -d $(DATADIR)/doc/jemalloc$(install_suffix)
+	@for d in $(DOCS_HTML); do \
+	echo "install -m 644 $$d $(DATADIR)/doc/jemalloc$(install_suffix)"; \
+	install -m 644 $$d $(DATADIR)/doc/jemalloc$(install_suffix); \
+done
+
+install_doc_man:
+	install -d $(MANDIR)/man3
+	@for d in $(DOCS_MAN3); do \
+	echo "install -m 644 $$d $(MANDIR)/man3"; \
+	install -m 644 $$d $(MANDIR)/man3; \
+done
+
+install_doc: install_doc_html install_doc_man
+
+install: install_bin install_include install_lib install_doc
+
+tests: $(CTESTS:$(srcroot)%.c=$(objroot)%$(EXE))
+
+check: tests
+	@mkdir -p $(objroot)test
+	@$(SHELL) -c 'total=0; \
+		failures=0; \
+		echo "========================================="; \
+		for t in $(CTESTS:$(srcroot)%.c=$(objroot)%); do \
+			total=`expr $$total + 1`; \
+			/bin/echo -n "$${t} ... "; \
+			$(TEST_LIBRARY_PATH) $${t}$(EXE) $(abs_srcroot) \
+			  $(abs_objroot) > $(objroot)$${t}.out 2>&1; \
+			if test -e "$(srcroot)$${t}.exp"; then \
+				diff -w -u $(srcroot)$${t}.exp \
+				  $(objroot)$${t}.out >/dev/null 2>&1; \
+				fail=$$?; \
+				if test "$${fail}" -eq "1" ; then \
+					failures=`expr $${failures} + 1`; \
+					echo "*** FAIL ***"; \
+				else \
+					echo "pass"; \
+				fi; \
+			else \
+				echo "*** FAIL *** (.exp file is missing)"; \
+				failures=`expr $${failures} + 1`; \
+			fi; \
+		done; \
+		echo "========================================="; \
+		echo "Failures: $${failures}/$${total}"'
+
+clean:
+	rm -f $(COBJS)
+	rm -f $(CPICOBJS)
+	rm -f $(COBJS:%.$(O)=%.d)
+	rm -f $(CPICOBJS:%.$(O)=%.d)
+	rm -f $(CTESTOBJS:%.$(O)=%$(EXE))
+	rm -f $(CTESTOBJS)
+	rm -f $(CTESTOBJS:%.$(O)=%.d)
+	rm -f $(CTESTOBJS:%.$(O)=%.out)
+	rm -f $(DSOS) $(STATIC_LIBS)
+
+distclean: clean
+	rm -rf $(objroot)autom4te.cache
+	rm -f $(objroot)config.log
+	rm -f $(objroot)config.status
+	rm -f $(objroot)config.stamp
+	rm -f $(cfghdrs_out)
+	rm -f $(cfgoutputs_out)
+
+relclean: distclean
+	rm -f $(objroot)configure
+	rm -f $(srcroot)VERSION
+	rm -f $(DOCS_HTML)
+	rm -f $(DOCS_MAN3)
+
+#===============================================================================
+# Re-configuration rules.
+
+ifeq ($(enable_autogen), 1)
+$(srcroot)configure : $(srcroot)configure.ac
+	cd ./$(srcroot) && $(AUTOCONF)
+
+$(objroot)config.status : $(srcroot)configure
+	./$(objroot)config.status --recheck
+
+$(srcroot)config.stamp.in : $(srcroot)configure.ac
+	echo stamp > $(srcroot)config.stamp.in
+
+$(objroot)config.stamp : $(cfgoutputs_in) $(cfghdrs_in) $(srcroot)configure
+	./$(objroot)config.status
+	@touch $@
+
+# There must be some action in order for make to re-read Makefile when it is
+# out of date.
+$(cfgoutputs_out) $(cfghdrs_out) : $(objroot)config.stamp
+	@true
+endif

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/README
@@ -0,0 +1,16 @@
+jemalloc is a general-purpose scalable concurrent malloc(3) implementation.
+This distribution is a "portable" implementation that currently targets
+FreeBSD, Linux, Apple OS X, and MinGW.  jemalloc is included as the default
+allocator in the FreeBSD and NetBSD operating systems, and it is used by the
+Mozilla Firefox web browser on Microsoft Windows-related platforms.  Depending
+on your needs, one of the other divergent versions may suit your needs better
+than this distribution.
+
+The COPYING file contains copyright and licensing information.
+
+The INSTALL file contains information on how to configure, build, and install
+jemalloc.
+
+The ChangeLog file contains a brief summary of changes for each release.
+
+URL: http://www.canonware.com/jemalloc/

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/VERSION
@@ -0,0 +1,1 @@
+3.0.0-0-gfc9b1dbf69f59d7ecfc4ac68da9847e017e1d046

new file mode 100755
--- /dev/null
+++ b/memory/jemalloc/src/autogen.sh
@@ -0,0 +1,17 @@
+#!/bin/sh
+
+for i in autoconf; do
+    echo "$i"
+    $i
+    if [ $? -ne 0 ]; then
+	echo "Error $? in $i"
+	exit 1
+    fi
+done
+
+echo "./configure --enable-autogen $@"
+./configure --enable-autogen $@
+if [ $? -ne 0 ]; then
+    echo "Error $? in ./configure"
+    exit 1
+fi

new file mode 100644
--- /dev/null
+++ b/memory/jemalloc/src/bin/jemalloc.sh.in
@@ -0,0 +1,9 @@
+#!/bin/sh
+
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+
+@LD_PRELOAD_VAR@=${libdir}/libjemalloc.@SOREV@
+export @LD_PRELOAD_VAR@
+exec "$@"

new file mode 100755
--- /dev/null
+++ b/memory/jemalloc/src/bin/pprof
@@ -0,0 +1,5348 @@
+#! /usr/bin/env perl
+
+# Copyright (c) 1998-2007, Google Inc.
+# All rights reserved.
+# 
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+# 
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+# 
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+# ---
+# Program for printing the profile generated by common/profiler.cc,
+# or by the heap profiler (common/debugallocation.cc)
+#
+# The profile contains a sequence of entries of the form:
+#       <count> <stack trace>
+# This program parses the profile, and generates user-readable
+# output.
+#
+# Examples:
+#
+# % tools/pprof "program" "profile"
+#   Enters "interactive" mode
+#
+# % tools/pprof --text "program" "profile"
+#   Generates one line per procedure
+#
+# % tools/pprof --gv "program" "profile"
+#   Generates annotated call-graph and displays via "gv"
+#
+# % tools/pprof --gv --focus=Mutex "program" "profile"
+#   Restrict to code paths that involve an entry that matches "Mutex"
+#
+# % tools/pprof --gv --focus=Mutex --ignore=string "program" "profile"
+#   Restrict to code paths that involve an entry that matches "Mutex"
+#   and does not match "string"
+#
+# % tools/pprof --list=IBF_CheckDocid "program" "profile"
+#   Generates disassembly listing of all routines with at least one
+#   sample that match the --list=<regexp> pattern.  The listing is
+#   annotated with the flat and cumulative sample counts at each line.
+#
+# % tools/pprof --disasm=IBF_CheckDocid "program" "profile"
+#   Generates disassembly listing of all routines with at least one
+#   sample that match the --disasm=<regexp> pattern.  The listing is
+#   annotated with the flat and cumulative sample counts at each PC value.
+#
+# TODO: Use color to indicate files?
+
+use strict;
+use warnings;
+use Getopt::Long;
+
+my $PPROF_VERSION = "2.0";
+
+# These are the object tools we use which can come from a
+# user-specified location using --tools, from the PPROF_TOOLS
+# environment variable, or from the environment.
+my %obj_tool_map = (
+  "objdump" => "objdump",
+  "nm" => "nm",
+  "addr2line" => "addr2line",
+  "c++filt" => "c++filt",
+  ## ConfigureObjTools may add architecture-specific entries:
+  #"nm_pdb" => "nm-pdb",       # for reading windows (PDB-format) executables
+  #"addr2line_pdb" => "addr2line-pdb",                                # ditto
+  #"otool" => "otool",         # equivalent of objdump on OS X
+);
+# NOTE: these are lists, so you can put in commandline flags if you want.
+my @DOT = ("dot");          # leave non-absolute, since it may be in /usr/local
+my @GV = ("gv");
+my @EVINCE = ("evince");    # could also be xpdf or perhaps acroread
+my @KCACHEGRIND = ("kcachegrind");
+my @PS2PDF = ("ps2pdf");
+# These are used for dynamic profiles
+my @URL_FETCHER = ("curl", "-s");
+
+# These are the web pages that servers need to support for dynamic profiles
+my $HEAP_PAGE = "/pprof/heap";
+my $PROFILE_PAGE = "/pprof/profile";   # must support cgi-param "?seconds=#"
+my $PMUPROFILE_PAGE = "/pprof/pmuprofile(?:\\?.*)?"; # must support cgi-param
+                                                # ?seconds=#&event=x&period=n
+my $GROWTH_PAGE = "/pprof/growth";
+my $CONTENTION_PAGE = "/pprof/contention";
+my $WALL_PAGE = "/pprof/wall(?:\\?.*)?";  # accepts options like namefilter
+my $FILTEREDPROFILE_PAGE = "/pprof/filteredprofile(?:\\?.*)?";
+my $CENSUSPROFILE_PAGE = "/pprof/censusprofile(?:\\?.*)?"; # must support cgi-param
+                                                       # "?seconds=#",
+                                                       # "?tags_regexp=#" and
+                                                       # "?type=#".
+my $SYMBOL_PAGE = "/pprof/symbol";     # must support symbol lookup via POST
+my $PROGRAM_NAME_PAGE = "/pprof/cmdline";
+
+# These are the web pages that can be named on the command line.
+# All the alternatives must begin with /.
+my $PROFILES = "($HEAP_PAGE|$PROFILE_PAGE|$PMUPROFILE_PAGE|" .
+               "$GROWTH_PAGE|$CONTENTION_PAGE|$WALL_PAGE|" .
+               "$FILTEREDPROFILE_PAGE|$CENSUSPROFILE_PAGE)";
+
+# default binary name
+my $UNKNOWN_BINARY = "(unknown)";
+
+# There is a pervasive dependency on the length (in hex characters,
+# i.e., nibbles) of an address, distinguishing between 32-bit and
+# 64-bit profiles.  To err on the safe size, default to 64-bit here:
+my $address_length = 16;
+
+my $dev_null = "/dev/null";
+if (! -e $dev_null && $^O =~ /MSWin/) {    # $^O is the OS perl was built for
+  $dev_null = "nul";
+}
+
+# A list of paths to search for shared object files
+my @prefix_list = ();
+
+# Special routine name that should not have any symbols.
+# Used as separator to parse "addr2line -i" output.
+my $sep_symbol = '_fini';
+my $sep_address = undef;
+
+##### Argument parsing #####
+
+sub usage_string {
+  return <<EOF;
+Usage:
+pprof [options] <program> <profiles>
+   <profiles> is a space separated list of profile names.
+pprof [options] <symbolized-profiles>
+   <symbolized-profiles> is a list of profile files where each file contains
+   the necessary symbol mappings  as well as profile data (likely generated
+   with --raw).
+pprof [options] <profile>
+   <profile> is a remote form.  Symbols are obtained from host:port$SYMBOL_PAGE
+
+   Each name can be:
+   /path/to/profile        - a path to a profile file
+   host:port[/<service>]   - a location of a service to get profile from
+
+   The /<service> can be $HEAP_PAGE, $PROFILE_PAGE, /pprof/pmuprofile,
+                         $GROWTH_PAGE, $CONTENTION_PAGE, /pprof/wall,
+                         $CENSUSPROFILE_PAGE, or /pprof/filteredprofile.
+   For instance:
+     pprof http://myserver.com:80$HEAP_PAGE
+   If /<service> is omitted, the service defaults to $PROFILE_PAGE (cpu profiling).
+pprof --symbols <program>
+   Maps addresses to symbol names.  In this mode, stdin should be a
+   list of library mappings, in the same format as is found in the heap-
+   and cpu-profile files (this loosely matches that of /proc/self/maps
+   on linux), followed by a list of hex addresses to map, one per line.
+
+   For more help with querying remote servers, including how to add the
+   necessary server-side support code, see this filename (or one like it):
+
+   /usr/doc/gperftools-$PPROF_VERSION/pprof_remote_servers.html
+
+Options:
+   --cum               Sort by cumulative data
+   --base=<base>       Subtract <base> from <profile> before display
+   --interactive       Run in interactive mode (interactive "help" gives help) [default]
+   --seconds=<n>       Length of time for dynamic profiles [default=30 secs]
+   --add_lib=<file>    Read additional symbols and line info from the given library
+   --lib_prefix=<dir>  Comma separated list of library path prefixes
+
+Reporting Granularity:
+   --addresses         Report at address level
+   --lines             Report at source line level
+   --functions         Report at function level [default]
+   --files             Report at source file level
+
+Output type:
+   --text              Generate text report
+   --callgrind         Generate callgrind format to stdout
+   --gv                Generate Postscript and display
+   --evince            Generate PDF and display
+   --web               Generate SVG and display
+   --list=<regexp>     Generate source listing of matching routines
+   --disasm=<regexp>   Generate disassembly of matching routines
+   --symbols           Print demangled symbol names found at given addresses
+   --dot               Generate DOT file to stdout
+   --ps                Generate Postcript to stdout
+   --pdf               Generate PDF to stdout
+   --svg               Generate SVG to stdout
+   --gif               Generate GIF to stdout
+   --raw               Generate symbolized pprof data (useful with remote fetch)
+
+Heap-Profile Options:
+   --inuse_space       Display in-use (mega)bytes [default]
+   --inuse_objects     Display in-use objects
+   --alloc_space       Display allocated (mega)bytes
+   --alloc_objects     Display allocated objects
+   --show_bytes        Display space in bytes
+   --drop_negative     Ignore negative differences
+
+Contention-profile options:
+   --total_delay       Display total delay at each region [default]
+   --contentions       Display number of delays at each region
+   --mean_delay        Display mean delay at each region
+
+Call-graph Options:
+   --nodecount=<n>     Show at most so many nodes [default=80]
+   --nodefraction=<f>  Hide nodes below <f>*total [default=.005]
+   --edgefraction=<f>  Hide edges below <f>*total [default=.001]
+   --maxdegree=<n>     Max incoming/outgoing edges per node [default=8]
+   --focus=<regexp>    Focus on nodes matching <regexp>
+   --ignore=<regexp>   Ignore nodes matching <regexp>
+   --scale=<n>         Set GV scaling [default=0]
+   --heapcheck         Make nodes with non-0 object counts
+                       (i.e. direct leak generators) more visible
+
+Miscellaneous:
+   --tools=<prefix or binary:fullpath>[,...]   \$PATH for object tool pathnames
+   --test              Run unit tests
+   --help              This message
+   --version           Version information
+
+Environment Variables:
+   PPROF_TMPDIR        Profiles directory. Defaults to \$HOME/pprof
+   PPROF_TOOLS         Prefix for object tools pathnames
+
+Examples:
+
+pprof /bin/ls ls.prof
+                       Enters "interactive" mode
+pprof --text /bin/ls ls.prof
+                       Outputs one line per procedure
+pprof --web /bin/ls ls.prof
+                       Displays annotated call-graph in web browser
+pprof --gv /bin/ls ls.prof
+                       Displays annotated call-graph via 'gv'
+pprof --gv --focus=Mutex /bin/ls ls.prof
+                       Restricts to code paths including a .*Mutex.* entry
+pprof --gv --focus=Mutex --ignore=string /bin/ls ls.prof
+                       Code paths including Mutex but not string
+pprof --list=getdir /bin/ls ls.prof
+                       (Per-line) annotated source listing for getdir()
+pprof --disasm=getdir /bin/ls ls.prof
+                       (Per-PC) annotated disassembly for getdir()
+
+pprof http://localhost:1234/
+                       Enters "interactive" mode
+pprof --text localhost:1234
+                       Outputs one line per procedure for localhost:1234
+pprof --raw localhost:1234 > ./local.raw
+pprof --text ./local.raw
+                       Fetches a remote profile for later analysis and then
+                       analyzes it in text mode.
+EOF
+}
+
+sub version_string {
+  return <<EOF
+pprof (part of gperftools $PPROF_VERSION)
+
+Copyright 1998-2007 Google Inc.
+
+This is BSD licensed software; see the source for copying conditions
+and license information.
+There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
+PARTICULAR PURPOSE.
+EOF
+}
+
+sub usage {
+  my $msg = shift;
+  print STDERR "$msg\n\n";
+  print STDERR usage_string();
+  print STDERR "\nFATAL ERROR: $msg\n";    # just as a reminder
+  exit(1);
+}
+
+sub Init() {
+  # Setup tmp-file name and handler to clean it up.
+  # We do this in the very beginning so that we can use
+  # error() and cleanup() function anytime here after.
+  $main::tmpfile_sym = "/tmp/pprof$$.sym";
+  $main::tmpfile_ps = "/tmp/pprof$$";
+  $main::next_tmpfile = 0;
+  $SIG{'INT'} = \&sighandler;
+
+  # Cache from filename/linenumber to source code
+  $main::source_cache = ();
+
+  $main::opt_help = 0;
+  $main::opt_version = 0;
+
+  $main::opt_cum = 0;
+  $main::opt_base = '';
+  $main::opt_addresses = 0;
+  $main::opt_lines = 0;
+  $main::opt_functions = 0;
+  $main::opt_files = 0;
+  $main::opt_lib_prefix = "";
+
+  $main::opt_text = 0;
+  $main::opt_callgrind = 0;
+  $main::opt_list = "";
+  $main::opt_disasm = "";
+  $main::opt_symbols = 0;
+  $main::opt_gv = 0;
+  $main::opt_evince = 0;
+  $main::opt_web = 0;
+  $main::opt_dot = 0;
+  $main::opt_ps = 0;
+  $main::opt_pdf = 0;
+  $main::opt_gif = 0;
+  $main::opt_svg = 0;
+  $main::opt_raw = 0;
+
+  $main::opt_nodecount = 80;
+  $main::opt_nodefraction = 0.005;
+  $main::opt_edgefraction = 0.001;
+  $main::opt_maxdegree = 8;
+  $main::opt_focus = '';
+  $main::opt_ignore = '';
+  $main::opt_scale = 0;
+  $main::opt_heapcheck = 0;
+  $main::opt_seconds = 30;
+  $main::opt_lib = "";
+
+  $main::opt_inuse_space   = 0;
+  $main::opt_inuse_objects = 0;
+  $main::opt_alloc_space   = 0;
+  $main::opt_alloc_objects = 0;
+  $main::opt_show_bytes    = 0;
+  $main::opt_drop_negative = 0;
+  $main::opt_interactive   = 0;
+
+  $main::opt_total_delay = 0;
+  $main::opt_contentions = 0;
+  $main::opt_mean_delay = 0;
+
+  $main::opt_tools   = "";
+  $main::opt_debug   = 0;
+  $main::opt_test    = 0;
+
+  # These are undocumented flags used only by unittests.
+  $main::opt_test_stride = 0;
+
+  # Are we using $SYMBOL_PAGE?
+  $main::use_symbol_page = 0;
+
+  # Files returned by TempName.
+  %main::tempnames = ();
+
+  # Type of profile we are dealing with
+  # Supported types:
+  #     cpu
+  #     heap
+  #     growth
+  #     contention
+  $main::profile_type = '';     # Empty type means "unknown"
+
+  GetOptions("help!"          => \$main::opt_help,
+             "version!"       => \$main::opt_version,
+             "cum!"           => \$main::opt_cum,
+             "base=s"         => \$main::opt_base,
+             "seconds=i"      => \$main::opt_seconds,
+             "add_lib=s"      => \$main::opt_lib,
+             "lib_prefix=s"   => \$main::opt_lib_prefix,
+             "functions!"     => \$main::opt_functions,
+             "lines!"         => \$main::opt_lines,
+             "addresses!"     => \$main::opt_addresses,
+             "files!"         => \$main::opt_files,
+             "text!"          => \$main::opt_text,
+             "callgrind!"     => \$main::opt_callgrind,
+             "list=s"         => \$main::opt_list,
+             "disasm=s"       => \$main::opt_disasm,
+             "symbols!"       => \$main::opt_symbols,
+             "gv!"            => \$main::opt_gv,
+             "evince!"        => \$main::opt_evince,
+             "web!"           => \$main::opt_web,
+             "dot!"           => \$main::opt_dot,
+             "ps!"            => \$main::opt_ps,
+             "pdf!"           => \$main::opt_pdf,
+             "svg!"           => \$main::opt_svg,
+             "gif!"           => \$main::opt_gif,
+             "raw!"           => \$main::opt_raw,
+             "interactive!"   => \$main::opt_interactive,
+             "nodecount=i"    => \$main::opt_nodecount,
+             "nodefraction=f" => \$main::opt_nodefraction,
+             "edgefraction=f" => \$main::opt_edgefraction,
+             "maxdegree=i"    => \$main::opt_maxdegree,
+             "focus=s"        => \$main::opt_focus,
+             "ignore=s"       => \$main::opt_ignore,
+             "scale=i"        => \$main::opt_scale,
+             "heapcheck"      => \$main::opt_heapcheck,
+             "inuse_space!"   => \$main::opt_inuse_space,
+             "inuse_objects!" => \$main::opt_inuse_objects,
+             "alloc_space!"   => \$main::opt_alloc_space,
+             "alloc_objects!" => \$main::opt_alloc_objects,
+             "show_bytes!"    => \$main::opt_show_bytes,
+             "drop_negative!" => \$main::opt_drop_negative,
+             "total_delay!"   => \$main::opt_total_delay,
+             "contentions!"   => \$main::opt_contentions,
+             "mean_delay!"    => \$main::opt_mean_delay,
+             "tools=s"        => \$main::opt_tools,
+             "test!"          => \$main::opt_test,
+             "debug!"         => \$main::opt_debug,
+             # Undocumented flags used only by unittests:
+             "test_stride=i"  => \$main::opt_test_stride,
+      ) || usage("Invalid option(s)");
+
+  # Deal with the standard --help and --version
+  if ($main::opt_help) {
+    print usage_string();
+    exit(0);
+  }
+
+  if ($main::opt_version) {
+    print version_string();
+    exit(0);
+  }
+
+  # Disassembly/listing/symbols mode requires address-level info
+  if ($main::opt_disasm || $main::opt_list || $main::opt_symbols) {
+    $main::opt_functions = 0;
+    $main::opt_lines = 0;
+    $main::opt_addresses = 1;
+    $main::opt_files = 0;
+  }
+
+  # Check heap-profiling flags
+  if ($main::opt_inuse_space +
+      $main::opt_inuse_objects +
+      $main::opt_alloc_space +
+      $main::opt_alloc_objects > 1) {
+    usage("Specify at most on of --inuse/--alloc options");
+  }
+
+  # Check output granularities
+  my $grains =
+      $main::opt_functions +
+      $main::opt_lines +
+      $main::opt_addresses +
+      $main::opt_files +
+      0;
+  if ($grains > 1) {
+    usage("Only specify one output granularity option");
+  }
+  if ($grains == 0) {
+    $main::opt_functions = 1;
+  }
+
+  # Check output modes
+  my $modes =
+      $main::opt_text +
+      $main::opt_callgrind +
+      ($main::opt_list eq '' ? 0 : 1) +
+      ($main::opt_disasm eq '' ? 0 : 1) +
+      ($main::opt_symbols == 0 ? 0 : 1) +
+      $main::opt_gv +
+      $main::opt_evince +
+      $main::opt_web +
+      $main::opt_dot +
+      $main::opt_ps +
+      $main::opt_pdf +
+      $main::opt_svg +
+      $main::opt_gif +
+      $main::opt_raw +
+      $main::opt_interactive +
+      0;
+  if ($modes > 1) {
+    usage("Only specify one output mode");
+  }
+  if ($modes == 0) {
+    if (-t STDOUT) {  # If STDOUT is a tty, activate interactive mode
+      $main::opt_interactive = 1;
+    } else {
+      $main::opt_text = 1;
+    }
+  }
+
+  if ($main::opt_test) {
+    RunUnitTests();
+    # Should not return
+    exit(1);
+  }
+
+  # Binary name and profile arguments list
+  $main::prog = "";
+  @main::pfile_args = ();
+
+  # Remote profiling without a binary (using $SYMBOL_PAGE instead)
+  if (@ARGV > 0) {
+    if (IsProfileURL($ARGV[0])) {
+      $main::use_symbol_page = 1;
+    } elsif (IsSymbolizedProfileFile($ARGV[0])) {
+      $main::use_symbolized_profile = 1;
+      $main::prog = $UNKNOWN_BINARY;  # will be set later from the profile file
+    }
+  }
+
+  if ($main::use_symbol_page || $main::use_symbolized_profile) {
+    # We don't need a binary!
+    my %disabled = ('--lines' => $main::opt_lines,
+                    '--disasm' => $main::opt_disasm);
+    for my $option (keys %disabled) {
+      usage("$option cannot be used without a binary") if $disabled{$option};
+    }
+    # Set $main::prog later...
+    scalar(@ARGV) || usage("Did not specify profile file");
+  } elsif ($main::opt_symbols) {
+    # --symbols needs a binary-name (to run nm on, etc) but not profiles
+    $main::prog = shift(@ARGV) || usage("Did not specify program");
+  } else {
+    $main::prog = shift(@ARGV) || usage("Did not specify program");
+    scalar(@ARGV) || usage("Did not specify profile file");
+  }
+
+  # Parse profile file/location arguments
+  foreach my $farg (@ARGV) {
+    if ($farg =~ m/(.*)\@([0-9]+)(|\/.*)$/ ) {
+      my $machine = $1;
+      my $num_machines = $2;
+      my $path = $3;
+      for (my $i = 0; $i < $num_machines; $i++) {
+        unshift(@main::pfile_args, "$i.$machine$path");
+      }
+    } else {
+      unshift(@main::pfile_args, $farg);
+    }
+  }
+
+  if ($main::use_symbol_page) {
+    unless (IsProfileURL($main::pfile_args[0])) {
+      error("The first profile should be a remote form to use $SYMBOL_PAGE\n");
+    }
+    CheckSymbolPage();
+    $main::prog = FetchProgramName();
+  } elsif (!$main::use_symbolized_profile) {  # may not need objtools!
+    ConfigureObjTools($main::prog)
+  }
+
+  # Break the opt_lib_prefix into the prefix_list array
+  @prefix_list = split (',', $main::opt_lib_prefix);
+
+  # Remove trailing / from the prefixes, in the list to prevent
+  # searching things like /my/path//lib/mylib.so
+  foreach (@prefix_list) {
+    s|/+$||;
+  }
+}
+
+sub Main() {
+  Init();
+  $main::collected_profile = undef;
+  @main::profile_files = ();
+  $main::op_time = time();
+
+  # Printing symbols is special and requires a lot less info that most.
+  if ($main::opt_symbols) {
+    PrintSymbols(*STDIN);   # Get /proc/maps and symbols output from stdin
+    return;
+  }
+
+  # Fetch all profile data
+  FetchDynamicProfiles();
+
+  # this will hold symbols that we read from the profile files
+  my $symbol_map = {};
+
+  # Read one profile, pick the last item on the list
+  my $data = ReadProfile($main::prog, pop(@main::profile_files));
+  my $profile = $data->{profile};
+  my $pcs = $data->{pcs};
+  my $libs = $data->{libs};   # Info about main program and shared libraries
+  $symbol_map = MergeSymbols($symbol_map, $data->{symbols});
+
+  # Add additional profiles, if available.
+  if (scalar(@main::profile_files) > 0) {
+    foreach my $pname (@main::profile_files) {
+      my $data2 = ReadProfile($main::prog, $pname);
+      $profile = AddProfile($profile, $data2->{profile});
+      $pcs = AddPcs($pcs, $data2->{pcs});
+      $symbol_map = MergeSymbols($symbol_map, $data2->{symbols});
+    }
+  }
+
+  # Subtract base from profile, if specified
+  if ($main::opt_base ne '') {
+    my $base = ReadProfile($main::prog, $main::opt_base);
+    $profile = SubtractProfile($profile, $base->{profile});
+    $pcs = AddPcs($pcs, $base->{pcs});
+    $symbol_map = MergeSymbols($symbol_map, $base->{symbols});
+  }
+
+  # Get total data in profile
+  my $total = TotalProfile($profile);
+
+  # Collect symbols
+  my $symbols;
+  if ($main::use_symbolized_profile) {
+    $symbols = FetchSymbols($pcs, $symbol_map);
+  } elsif ($main::use_symbol_page) {
+    $symbols = FetchSymbols($pcs);
+  } else {
+    # TODO(csilvers): $libs uses the /proc/self/maps data from profile1,
+    # which may differ from the data from subsequent profiles, especially
+    # if they were run on different machines.  Use appropriate libs for
+    # each pc somehow.
+    $symbols = ExtractSymbols($libs, $pcs);
+  }
+
+  # Remove uniniteresting stack items
+  $profile = RemoveUninterestingFrames($symbols, $profile);
+
+  # Focus?
+  if ($main::opt_focus ne '') {
+    $profile = FocusProfile($symbols, $profile, $main::opt_focus);
+  }
+
+  # Ignore?
+  if ($main::opt_ignore ne '') {
+    $profile = IgnoreProfile($symbols, $profile, $main::opt_ignore);
+  }
+
+  my $calls = ExtractCalls($symbols, $profile);
+
+  # Reduce profiles to required output granularity, and also clean
+  # each stack trace so a given entry exists at most once.
+  my $reduced = ReduceProfile($symbols, $profile);
+
+  # Get derived profiles
+  my $flat = FlatProfile($reduced);
+  my $cumulative = CumulativeProfile($reduced);
+
+  # Print
+  if (!$main::opt_interactive) {
+    if ($main::opt_disasm) {
+      PrintDisassembly($libs, $flat, $cumulative, $main::opt_disasm);
+    } elsif ($main::opt_list) {
+      PrintListing($total, $libs, $flat, $cumulative, $main::opt_list, 0);
+    } elsif ($main::opt_text) {
+      # Make sure the output is empty when have nothing to report
+      # (only matters when --heapcheck is given but we must be
+      # compatible with old branches that did not pass --heapcheck always):
+      if ($total != 0) {
+        printf("Total: %s %s\n", Unparse($total), Units());
+      }
+      PrintText($symbols, $flat, $cumulative, -1);
+    } elsif ($main::opt_raw) {
+      PrintSymbolizedProfile($symbols, $profile, $main::prog);
+    } elsif ($main::opt_callgrind) {
+      PrintCallgrind($calls);
+    } else {
+      if (PrintDot($main::prog, $symbols, $profile, $flat, $cumulative, $total)) {
+        if ($main::opt_gv) {
+          RunGV(TempName($main::next_tmpfile, "ps"), "");
+        } elsif ($main::opt_evince) {
+          RunEvince(TempName($main::next_tmpfile, "pdf"), "");
+        } elsif ($main::opt_web) {
+          my $tmp = TempName($main::next_tmpfile, "svg");
+          RunWeb($tmp);
+          # The command we run might hand the file name off
+          # to an already running browser instance and then exit.
+          # Normally, we'd remove $tmp on exit (right now),
+          # but fork a child to remove $tmp a little later, so that the
+          # browser has time to load it first.
+          delete $main::tempnames{$tmp};
+          if (fork() == 0) {
+            sleep 5;
+            unlink($tmp);
+            exit(0);
+          }
+        }
+      } else {
+        cleanup();
+        exit(1);
+      }
+    }
+  } else {
+    InteractiveMode($profile, $symbols, $libs, $total);
+  }
+
+  cleanup();
+  exit(0);
+}
+
+##### Entry Point #####
+
+Main();
+
+# Temporary code to detect if we're running on a Goobuntu system.
+# These systems don't have the right stuff installed for the special
+# Readline libraries to work, so as a temporary workaround, we default
+# to using the normal stdio code, rather than the fancier readline-based
+# code
+sub ReadlineMightFail {
+  if (-e '/lib/libtermcap.so.2') {
+    return 0;  # libtermcap exists, so readline should be okay
+  } else {
+    return 1;
+  }
+}
+
+sub RunGV {
+  my $fname = shift;
+  my $bg = shift;       # "" or " &" if we should run in background
+  if (!system(ShellEscape(@GV, "--version") . " >$dev_null 2>&1")) {
+    # Options using double dash are supported by this gv version.
+    # Also, turn on noantialias to better handle bug in gv for
+    # postscript files with large dimensions.
+    # TODO: Maybe we should not pass the --noantialias flag
+    # if the gv version is known to work properly without the flag.
+    system(ShellEscape(@GV, "--scale=$main::opt_scale", "--noantialias", $fname)
+           . $bg);
+  } else {
+    # Old gv version - only supports options that use single dash.
+    print STDERR ShellEscape(@GV, "-scale", $main::opt_scale) . "\n";
+    system(ShellEscape(@GV, "-scale", "$main::opt_scale", $fname) . $bg);
+  }
+}
+
+sub RunEvince {
+  my $fname = shift;
+  my $bg = shift;       # "" or " &" if we should run in background
+  system(ShellEscape(@EVINCE, $fname) . $bg);
+}
+
+sub RunWeb {
+  my $fname = shift;
+  print STDERR "Loading web page file:///$fname\n";
+
+  if (`uname` =~ /Darwin/) {
+    # OS X: open will use standard preference for SVG files.
+    system("/usr/bin/open", $fname);
+    return;
+  }
+
+  # Some kind of Unix; try generic symlinks, then specific browsers.
+  # (Stop once we find one.)
+  # Works best if the browser is already running.
+  my @alt = (
+    "/etc/alternatives/gnome-www-browser",
+    "/etc/alternatives/x-www-browser",
+    "google-chrome",
+    "firefox",
+  );
+  foreach my $b (@alt) {
+    if (system($b, $fname) == 0) {
+      return;
+    }
+  }
+
+  print STDERR "Could not load web browser.\n";
+}
+
+sub RunKcachegrind {
+  my $fname = shift;
+  my $bg = shift;       # "" or " &" if we should run in background
+  print STDERR "Starting '@KCACHEGRIND " . $fname . $bg . "'\n";
+  system(ShellEscape(@KCACHEGRIND, $fname) . $bg);
+}
+
+
+##### Interactive helper routines #####
+
+sub InteractiveMode {
+  $| = 1;  # Make output unbuffered for interactive mode
+  my ($orig_profile, $symbols, $libs, $total) = @_;
+
+  print STDERR "Welcome to pprof!  For help, type 'help'.\n";
+
+  # Use ReadLine if it's installed and input comes from a console.
+  if ( -t STDIN &&
+       !ReadlineMightFail() &&
+       defined(eval {require Term::ReadLine}) ) {
+    my $term = new Term::ReadLine 'pprof';
+    while ( defined ($_ = $term->readline('(pprof) '))) {
+      $term->addhistory($_) if /\S/;
+      if (!InteractiveCommand($orig_profile, $symbols, $libs, $total, $_)) {
+        last;    # exit when we get an interactive command to quit
+      }
+    }
+  } else {       # don't have readline
+    while (1) {
+      print STDERR "(pprof) ";
+      $_ = <STDIN>;
+      last if ! defined $_ ;
+      s/\r//g;         # turn windows-looking lines into unix-looking lines
+
+      # Save some flags that might be reset by InteractiveCommand()
+      my $save_opt_lines = $main::opt_lines;
+
+      if (!InteractiveCommand($orig_profile, $symbols, $libs, $total, $_)) {
+        last;    # exit when we get an interactive command to quit
+      }
+
+      # Restore flags
+      $main::opt_lines = $save_opt_lines;
+    }
+  }
+}
+
+# Takes two args: orig profile, and command to run.
+# Returns 1 if we should keep going, or 0 if we were asked to quit
+sub InteractiveCommand {
+  my($orig_profile, $symbols, $libs, $total, $command) = @_;
+  $_ = $command;                # just to make future m//'s easier
+  if (!defined($_)) {
+    print STDERR "\n";
+    return 0;
+  }
+  if (m/^\s*quit/) {
+    return 0;
+  }
+  if (m/^\s*help/) {
+    InteractiveHelpMessage();
+    return 1;
+  }
+  # Clear all the mode options -- mode is controlled by "$command"
+  $main::opt_text = 0;
+  $main::opt_callgrind = 0;
+  $main::opt_disasm = 0;
+  $main::opt_list = 0;
+  $main::opt_gv = 0;
+  $main::opt_evince = 0;
+  $main::opt_cum = 0;
+
+  if (m/^\s*(text|top)(\d*)\s*(.*)/) {
+    $main::opt_text = 1;
+
+    my $line_limit = ($2 ne "") ? int($2) : 10;
+
+    my $routine;
+    my $ignore;
+    ($routine, $ignore) = ParseInteractiveArgs($3);
+
+    my $profile = ProcessProfile($total, $orig_profile, $symbols, "", $ignore);
+    my $reduced = ReduceProfile($symbols, $profile);
+
+    # Get derived profiles
+    my $flat = FlatProfile($reduced);
+    my $cumulative = CumulativeProfile($reduced);
+
+    PrintText($symbols, $flat, $cumulative, $line_limit);
+    return 1;
+  }
+  if (m/^\s*callgrind\s*([^ \n]*)/) {
+    $main::opt_callgrind = 1;
+
+    # Get derived profiles
+    my $calls = ExtractCalls($symbols, $orig_profile);
+    my $filename = $1;
+    if ( $1 eq '' ) {
+      $filename = TempName($main::next_tmpfile, "callgrind");
+    }
+    PrintCallgrind($calls, $filename);
+    if ( $1 eq '' ) {
+      RunKcachegrind($filename, " & ");
+      $main::next_tmpfile++;
+    }
+
+    return 1;
+  }
+  if (m/^\s*(web)?list\s*(.+)/) {
+    my $html = (defined($1) && ($1 eq "web"));
+    $main::opt_list = 1;
+
+    my $routine;
+    my $ignore;
+    ($routine, $ignore) = ParseInteractiveArgs($2);
+
+    my $profile = ProcessProfile($total, $orig_profile, $symbols, "", $ignore);
+    my $reduced = ReduceProfile($symbols, $profile);
+
+    # Get derived profiles
+    my $flat = FlatProfile($reduced);
+    my $cumulative = CumulativeProfile($reduced);
+
+    PrintListing($total, $libs, $flat, $cumulative, $routine, $html);
+    return 1;
+  }
+  if (m/^\s*disasm\s*(.+)/) {
+    $main::opt_disasm = 1;
+
+    my $routine;
+    my $ignore;
+    ($routine, $ignore) = ParseInteractiveArgs($1);
+
+    # Process current profile to account for various settings
+    my $profile = ProcessProfile($total, $orig_profile, $symbols, "", $ignore);
+    my $reduced = ReduceProfile($symbols, $profile);
+
+    # Get derived profiles
+    my $flat = FlatProfile($reduced);
+    my $cumulative = CumulativeProfile($reduced);
+
+    PrintDisassembly($libs, $flat, $cumulative, $routine);
+    return 1;
+  }
+  if (m/^\s*(gv|web|evince)\s*(.*)/) {
+    $main::opt_gv = 0;
+    $main::opt_evince = 0;
+    $main::opt_web = 0;
+    if ($1 eq "gv") {
+      $main::opt_gv = 1;
+    } elsif ($1 eq "evince") {
+      $main::opt_evince = 1;
+    } elsif ($1 eq "web") {
+      $main::opt_web = 1;
+    }
+
+    my $focus;
+    my $ignore;
+    ($focus, $ignore) = ParseInteractiveArgs($2);
+
+    # Process current profile to account for various settings
+    my $profile = ProcessProfile($total, $orig_profile, $symbols,
+                                 $focus, $ignore);
+    my $reduced = ReduceProfile($symbols, $profile);
+
+    # Get derived profiles
+    my $flat = FlatProfile($reduced);
+    my $cumulative = CumulativeProfile($reduced);
+
+    if (PrintDot($main::prog, $symbols, $profile, $flat, $cumulative, $total)) {
+      if ($main::opt_gv) {
+        RunGV(TempName($main::next_tmpfile, "ps"), " &");
+      } elsif ($main::opt_evince) {
+        RunEvince(TempName($main::next_tmpfile, "pdf"), " &");
+      } elsif ($main::opt_web) {
+        RunWeb(TempName($main::next_tmpfile, "svg"));
+      }
+      $main::next_tmpfile++;
+    }
+    return 1;
+  }
+  if (m/^\s*$/) {
+    return 1;
+  }
+  print STDERR "Unknown command: try 'help'.\n";
+  return 1;
+}
+
+
+sub ProcessProfile {
+  my $total_count = shift;
+  my $orig_profile = shift;
+  my $symbols = shift;
+  my $focus = shift;
+  my $ignore = shift;
+
+  # Process current profile to account for various settings
+  my $profile = $orig_profile;
+  printf("Total: %s %s\n", Unparse($total_count), Units());
+  if ($focus ne '') {
+    $profile = FocusProfile($symbols, $profile, $focus);
+    my $focus_count = TotalProfile($profile);
+    printf("After focusing on '%s': %s %s of %s (%0.1f%%)\n",
+           $focus,
+           Unparse($focus_count), Units(),
+           Unparse($total_count), ($focus_count*100.0) / $total_count);
+  }
+  if ($ignore ne '') {
+    $profile = IgnoreProfile($symbols, $profile, $ignore);
+    my $ignore_count = TotalProfile($profile);
+    printf("After ignoring '%s': %s %s of %s (%0.1f%%)\n",
+           $ignore,
+           Unparse($ignore_count), Units(),
+           Unparse($total_count),
+           ($ignore_count*100.0) / $total_count);
+  }
+
+  return $profile;
+}
+
+sub InteractiveHelpMessage {
+  print STDERR <<ENDOFHELP;
+Interactive pprof mode
+
+Commands:
+  gv
+  gv [focus] [-ignore1] [-ignore2]
+      Show graphical hierarchical display of current profile.  Without
+      any arguments, shows all samples in the profile.  With the optional
+      "focus" argument, restricts the samples shown to just those where
+      the "focus" regular expression matches a routine name on the stack
+      trace.
+
+  web
+  web [focus] [-ignore1] [-ignore2]
+      Like GV, but displays profile in your web browser instead of using
+      Ghostview. Works best if your web browser is already running.
+      To change the browser that gets used:
+      On Linux, set the /etc/alternatives/gnome-www-browser symlink.
+      On OS X, change the Finder association for SVG files.
+
+  list [routine_regexp] [-ignore1] [-ignore2]
+      Show source listing of routines whose names match "routine_regexp"
+
+  weblist [routine_regexp] [-ignore1] [-ignore2]
+     Displays a source listing of routines whose names match "routine_regexp"
+     in a web browser.  You can click on source lines to view the
+     corresponding disassembly.
+
+  top [--cum] [-ignore1] [-ignore2]
+  top20 [--cum] [-ignore1] [-ignore2]
+  top37 [--cum] [-ignore1] [-ignore2]
+      Show top lines ordered by flat profile count, or cumulative count
+      if --cum is specified.  If a number is present after 'top', the
+      top K routines will be shown (defaults to showing the top 10)
+
+  disasm [routine_regexp] [-ignore1] [-ignore2]
+      Show disassembly of routines whose names match "routine_regexp",
+      annotated with sample counts.
+
+  callgrind
+  callgrind [filename]
+      Generates callgrind file. If no filename is given, kcachegrind is called.
+
+  help - This listing
+  quit or ^D - End pprof
+
+For commands that accept optional -ignore tags, samples where any routine in
+the stack trace matches the regular expression in any of the -ignore
+parameters will be ignored.
+
+Further pprof details are available at this location (or one similar):
+
+ /usr/doc/gperftools-$PPROF_VERSION/cpu_profiler.html
+ /usr/doc/gperftools-$PPROF_VERSION/heap_profiler.html
+
+ENDOFHELP
+}
+sub ParseInteractiveArgs {
+  my $args = shift;
+  my $focus = "";
+  my $ignore = "";
+  my @x = split(/ +/, $args);
+  foreach $a (@x) {
+    if ($a =~ m/^(--|-)lines$/) {
+      $main::opt_lines = 1;
+    } elsif ($a =~ m/^(--|-)cum$/) {
+      $main::opt_cum = 1;
+    } elsif ($a =~ m/^-(.*)/) {
+      $ignore .= (($ignore ne "") ? "|" : "" ) . $1;
+    } else {
+      $focus .= (($focus ne "") ? "|" : "" ) . $a;
+    }
+  }
+  if ($ignore ne "") {
+    print STDERR "Ignoring samples in call stacks that match '$ignore'\n";
+  }
+  return ($focus, $ignore);
+}
+
+##### Output code #####
+
+sub TempName {
+  my $fnum = shift;
+  my $ext = shift;
+  my $file = "$main::tmpfile_ps.$fnum.$ext";
+  $main::tempnames{$file} = 1;
+  return $file;
+}
+
+# Print profile data in packed binary format (64-bit) to standard out
+sub PrintProfileData {
+  my $profile = shift;
+
+  # print header (64-bit style)
+  # (zero) (header-size) (version) (sample-period) (zero)
+  print pack('L*', 0, 0, 3, 0, 0, 0, 1, 0, 0, 0);
+
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @addrs = split(/\n/, $k);
+    if ($#addrs >= 0) {
+      my $depth = $#addrs + 1;
+      # int(foo / 2**32) is the only reliable way to get rid of bottom
+      # 32 bits on both 32- and 64-bit systems.
+      print pack('L*', $count & 0xFFFFFFFF, int($count / 2**32));
+      print pack('L*', $depth & 0xFFFFFFFF, int($depth / 2**32));
+
+      foreach my $full_addr (@addrs) {
+        my $addr = $full_addr;
+        $addr =~ s/0x0*//;  # strip off leading 0x, zeroes
+        if (length($addr) > 16) {
+          print STDERR "Invalid address in profile: $full_addr\n";
+          next;
+        }
+        my $low_addr = substr($addr, -8);       # get last 8 hex chars
+        my $high_addr = substr($addr, -16, 8);  # get up to 8 more hex chars
+        print pack('L*', hex('0x' . $low_addr), hex('0x' . $high_addr));
+      }
+    }
+  }
+}
+
+# Print symbols and profile data
+sub PrintSymbolizedProfile {
+  my $symbols = shift;
+  my $profile = shift;
+  my $prog = shift;
+
+  $SYMBOL_PAGE =~ m,[^/]+$,;    # matches everything after the last slash
+  my $symbol_marker = $&;
+
+  print '--- ', $symbol_marker, "\n";
+  if (defined($prog)) {
+    print 'binary=', $prog, "\n";
+  }
+  while (my ($pc, $name) = each(%{$symbols})) {
+    my $sep = ' ';
+    print '0x', $pc;
+    # We have a list of function names, which include the inlined
+    # calls.  They are separated (and terminated) by --, which is
+    # illegal in function names.
+    for (my $j = 2; $j <= $#{$name}; $j += 3) {
+      print $sep, $name->[$j];
+      $sep = '--';
+    }
+    print "\n";
+  }
+  print '---', "\n";
+
+  $PROFILE_PAGE =~ m,[^/]+$,;    # matches everything after the last slash
+  my $profile_marker = $&;
+  print '--- ', $profile_marker, "\n";
+  if (defined($main::collected_profile)) {
+    # if used with remote fetch, simply dump the collected profile to output.
+    open(SRC, "<$main::collected_profile");
+    while (<SRC>) {
+      print $_;
+    }
+    close(SRC);
+  } else {
+    # dump a cpu-format profile to standard out
+    PrintProfileData($profile);
+  }
+}
+
+# Print text output
+sub PrintText {
+  my $symbols = shift;
+  my $flat = shift;
+  my $cumulative = shift;
+  my $line_limit = shift;
+
+  my $total = TotalProfile($flat);
+
+  # Which profile to sort by?
+  my $s = $main::opt_cum ? $cumulative : $flat;
+
+  my $running_sum = 0;
+  my $lines = 0;
+  foreach my $k (sort { GetEntry($s, $b) <=> GetEntry($s, $a) || $a cmp $b }
+                 keys(%{$cumulative})) {
+    my $f = GetEntry($flat, $k);
+    my $c = GetEntry($cumulative, $k);
+    $running_sum += $f;
+
+    my $sym = $k;
+    if (exists($symbols->{$k})) {
+      $sym = $symbols->{$k}->[0] . " " . $symbols->{$k}->[1];
+      if ($main::opt_addresses) {
+        $sym = $k . " " . $sym;
+      }
+    }
+
+    if ($f != 0 || $c != 0) {
+      printf("%8s %6s %6s %8s %6s %s\n",
+             Unparse($f),
+             Percent($f, $total),
+             Percent($running_sum, $total),
+             Unparse($c),
+             Percent($c, $total),
+             $sym);
+    }
+    $lines++;
+    last if ($line_limit >= 0 && $lines >= $line_limit);
+  }
+}
+
+# Callgrind format has a compression for repeated function and file
+# names.  You show the name the first time, and just use its number
+# subsequently.  This can cut down the file to about a third or a
+# quarter of its uncompressed size.  $key and $val are the key/value
+# pair that would normally be printed by callgrind; $map is a map from
+# value to number.
+sub CompressedCGName {
+  my($key, $val, $map) = @_;
+  my $idx = $map->{$val};
+  # For very short keys, providing an index hurts rather than helps.
+  if (length($val) <= 3) {
+    return "$key=$val\n";
+  } elsif (defined($idx)) {
+    return "$key=($idx)\n";
+  } else {
+    # scalar(keys $map) gives the number of items in the map.
+    $idx = scalar(keys(%{$map})) + 1;
+    $map->{$val} = $idx;
+    return "$key=($idx) $val\n";
+  }
+}
+
+# Print the call graph in a way that's suiteable for callgrind.
+sub PrintCallgrind {
+  my $calls = shift;
+  my $filename;
+  my %filename_to_index_map;
+  my %fnname_to_index_map;
+
+  if ($main::opt_interactive) {
+    $filename = shift;
+    print STDERR "Writing callgrind file to '$filename'.\n"
+  } else {
+    $filename = "&STDOUT";
+  }
+  open(CG, ">$filename");
+  printf CG ("events: Hits\n\n");
+  foreach my $call ( map { $_->[0] }
+                     sort { $a->[1] cmp $b ->[1] ||
+                            $a->[2] <=> $b->[2] }
+                     map { /([^:]+):(\d+):([^ ]+)( -> ([^:]+):(\d+):(.+))?/;
+                           [$_, $1, $2] }
+                     keys %$calls ) {
+    my $count = int($calls->{$call});
+    $call =~ /([^:]+):(\d+):([^ ]+)( -> ([^:]+):(\d+):(.+))?/;
+    my ( $caller_file, $caller_line, $caller_function,
+         $callee_file, $callee_line, $callee_function ) =
+       ( $1, $2, $3, $5, $6, $7 );
+
+    # TODO(csilvers): for better compression, collect all the
+    # caller/callee_files and functions first, before printing
+    # anything, and only compress those referenced more than once.
+    printf CG CompressedCGName("fl", $caller_file, \%filename_to_index_map);
+    printf CG CompressedCGName("fn", $caller_function, \%fnname_to_index_map);
+    if (defined $6) {
+      printf CG CompressedCGName("cfl", $callee_file, \%filename_to_index_map);
+      printf CG CompressedCGName("cfn", $callee_function, \%fnname_to_index_map);
+      printf CG ("calls=$count $callee_line\n");
+    }
+    printf CG ("$caller_line $count\n\n");
+  }
+}
+
+# Print disassembly for all all routines that match $main::opt_disasm
+sub PrintDisassembly {
+  my $libs = shift;
+  my $flat = shift;
+  my $cumulative = shift;
+  my $disasm_opts = shift;
+
+  my $total = TotalProfile($flat);
+
+  foreach my $lib (@{$libs}) {
+    my $symbol_table = GetProcedureBoundaries($lib->[0], $disasm_opts);
+    my $offset = AddressSub($lib->[1], $lib->[3]);
+    foreach my $routine (sort ByName keys(%{$symbol_table})) {
+      my $start_addr = $symbol_table->{$routine}->[0];
+      my $end_addr = $symbol_table->{$routine}->[1];
+      # See if there are any samples in this routine
+      my $length = hex(AddressSub($end_addr, $start_addr));
+      my $addr = AddressAdd($start_addr, $offset);
+      for (my $i = 0; $i < $length; $i++) {
+        if (defined($cumulative->{$addr})) {
+          PrintDisassembledFunction($lib->[0], $offset,
+                                    $routine, $flat, $cumulative,
+                                    $start_addr, $end_addr, $total);
+          last;
+        }
+        $addr = AddressInc($addr);
+      }
+    }
+  }
+}
+
+# Return reference to array of tuples of the form:
+#       [start_address, filename, linenumber, instruction, limit_address]
+# E.g.,
+#       ["0x806c43d", "/foo/bar.cc", 131, "ret", "0x806c440"]
+sub Disassemble {
+  my $prog = shift;
+  my $offset = shift;
+  my $start_addr = shift;
+  my $end_addr = shift;
+
+  my $objdump = $obj_tool_map{"objdump"};
+  my $cmd = ShellEscape($objdump, "-C", "-d", "-l", "--no-show-raw-insn",
+                        "--start-address=0x$start_addr",
+                        "--stop-address=0x$end_addr", $prog);
+  open(OBJDUMP, "$cmd |") || error("$cmd: $!\n");
+  my @result = ();
+  my $filename = "";
+  my $linenumber = -1;
+  my $last = ["", "", "", ""];
+  while (<OBJDUMP>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    chop;
+    if (m|\s*([^:\s]+):(\d+)\s*$|) {
+      # Location line of the form:
+      #   <filename>:<linenumber>
+      $filename = $1;
+      $linenumber = $2;
+    } elsif (m/^ +([0-9a-f]+):\s*(.*)/) {
+      # Disassembly line -- zero-extend address to full length
+      my $addr = HexExtend($1);
+      my $k = AddressAdd($addr, $offset);
+      $last->[4] = $k;   # Store ending address for previous instruction
+      $last = [$k, $filename, $linenumber, $2, $end_addr];
+      push(@result, $last);
+    }
+  }
+  close(OBJDUMP);
+  return @result;
+}
+
+# The input file should contain lines of the form /proc/maps-like
+# output (same format as expected from the profiles) or that looks
+# like hex addresses (like "0xDEADBEEF").  We will parse all
+# /proc/maps output, and for all the hex addresses, we will output
+# "short" symbol names, one per line, in the same order as the input.
+sub PrintSymbols {
+  my $maps_and_symbols_file = shift;
+
+  # ParseLibraries expects pcs to be in a set.  Fine by us...
+  my @pclist = ();   # pcs in sorted order
+  my $pcs = {};
+  my $map = "";
+  foreach my $line (<$maps_and_symbols_file>) {
+    $line =~ s/\r//g;    # turn windows-looking lines into unix-looking lines
+    if ($line =~ /\b(0x[0-9a-f]+)\b/i) {
+      push(@pclist, HexExtend($1));
+      $pcs->{$pclist[-1]} = 1;
+    } else {
+      $map .= $line;
+    }
+  }
+
+  my $libs = ParseLibraries($main::prog, $map, $pcs);
+  my $symbols = ExtractSymbols($libs, $pcs);
+
+  foreach my $pc (@pclist) {
+    # ->[0] is the shortname, ->[2] is the full name
+    print(($symbols->{$pc}->[0] || "??") . "\n");
+  }
+}
+
+
+# For sorting functions by name
+sub ByName {
+  return ShortFunctionName($a) cmp ShortFunctionName($b);
+}
+
+# Print source-listing for all all routines that match $list_opts
+sub PrintListing {
+  my $total = shift;
+  my $libs = shift;
+  my $flat = shift;
+  my $cumulative = shift;
+  my $list_opts = shift;
+  my $html = shift;
+
+  my $output = \*STDOUT;
+  my $fname = "";
+
+  if ($html) {
+    # Arrange to write the output to a temporary file
+    $fname = TempName($main::next_tmpfile, "html");
+    $main::next_tmpfile++;
+    if (!open(TEMP, ">$fname")) {
+      print STDERR "$fname: $!\n";
+      return;
+    }
+    $output = \*TEMP;
+    print $output HtmlListingHeader();
+    printf $output ("<div class=\"legend\">%s<br>Total: %s %s</div>\n",
+                    $main::prog, Unparse($total), Units());
+  }
+
+  my $listed = 0;
+  foreach my $lib (@{$libs}) {
+    my $symbol_table = GetProcedureBoundaries($lib->[0], $list_opts);
+    my $offset = AddressSub($lib->[1], $lib->[3]);
+    foreach my $routine (sort ByName keys(%{$symbol_table})) {
+      # Print if there are any samples in this routine
+      my $start_addr = $symbol_table->{$routine}->[0];
+      my $end_addr = $symbol_table->{$routine}->[1];
+      my $length = hex(AddressSub($end_addr, $start_addr));
+      my $addr = AddressAdd($start_addr, $offset);
+      for (my $i = 0; $i < $length; $i++) {
+        if (defined($cumulative->{$addr})) {
+          $listed += PrintSource(
+            $lib->[0], $offset,
+            $routine, $flat, $cumulative,
+            $start_addr, $end_addr,
+            $html,
+            $output);
+          last;
+        }
+        $addr = AddressInc($addr);
+      }
+    }
+  }
+
+  if ($html) {
+    if ($listed > 0) {
+      print $output HtmlListingFooter();
+      close($output);
+      RunWeb($fname);
+    } else {
+      close($output);
+      unlink($fname);
+    }
+  }
+}
+
+sub HtmlListingHeader {
+  return <<'EOF';
+<DOCTYPE html>
+<html>
+<head>
+<title>Pprof listing</title>
+<style type="text/css">
+body {
+  font-family: sans-serif;
+}
+h1 {
+  font-size: 1.5em;
+  margin-bottom: 4px;
+}
+.legend {
+  font-size: 1.25em;
+}
+.line {
+  color: #aaaaaa;
+}
+.nop {
+  color: #aaaaaa;
+}
+.unimportant {
+  color: #cccccc;
+}
+.disasmloc {
+  color: #000000;
+}
+.deadsrc {
+  cursor: pointer;
+}
+.deadsrc:hover {
+  background-color: #eeeeee;
+}
+.livesrc {
+  color: #0000ff;
+  cursor: pointer;
+}
+.livesrc:hover {
+  background-color: #eeeeee;
+}
+.asm {
+  color: #008800;
+  display: none;
+}
+</style>
+<script type="text/javascript">
+function pprof_toggle_asm(e) {
+  var target;
+  if (!e) e = window.event;
+  if (e.target) target = e.target;
+  else if (e.srcElement) target = e.srcElement;
+
+  if (target) {
+    var asm = target.nextSibling;
+    if (asm && asm.className == "asm") {
+      asm.style.display = (asm.style.display == "block" ? "" : "block");
+      e.preventDefault();
+      return false;
+    }
+  }
+}
+</script>
+</head>
+<body>
+EOF
+}
+
+sub HtmlListingFooter {
+  return <<'EOF';
+</body>
+</html>
+EOF
+}
+
+sub HtmlEscape {
+  my $text = shift;
+  $text =~ s/&/&amp;/g;
+  $text =~ s/</&lt;/g;
+  $text =~ s/>/&gt;/g;
+  return $text;
+}
+
+# Returns the indentation of the line, if it has any non-whitespace
+# characters.  Otherwise, returns -1.
+sub Indentation {
+  my $line = shift;
+  if (m/^(\s*)\S/) {
+    return length($1);
+  } else {
+    return -1;
+  }
+}
+
+# If the symbol table contains inlining info, Disassemble() may tag an
+# instruction with a location inside an inlined function.  But for
+# source listings, we prefer to use the location in the function we
+# are listing.  So use MapToSymbols() to fetch full location
+# information for each instruction and then pick out the first
+# location from a location list (location list contains callers before
+# callees in case of inlining).
+#
+# After this routine has run, each entry in $instructions contains:
+#   [0] start address
+#   [1] filename for function we are listing
+#   [2] line number for function we are listing
+#   [3] disassembly
+#   [4] limit address
+#   [5] most specific filename (may be different from [1] due to inlining)
+#   [6] most specific line number (may be different from [2] due to inlining)
+sub GetTopLevelLineNumbers {
+  my ($lib, $offset, $instructions) = @_;
+  my $pcs = [];
+  for (my $i = 0; $i <= $#{$instructions}; $i++) {
+    push(@{$pcs}, $instructions->[$i]->[0]);
+  }
+  my $symbols = {};
+  MapToSymbols($lib, $offset, $pcs, $symbols);
+  for (my $i = 0; $i <= $#{$instructions}; $i++) {
+    my $e = $instructions->[$i];
+    push(@{$e}, $e->[1]);
+    push(@{$e}, $e->[2]);
+    my $addr = $e->[0];
+    my $sym = $symbols->{$addr};
+    if (defined($sym)) {
+      if ($#{$sym} >= 2 && $sym->[1] =~ m/^(.*):(\d+)$/) {
+        $e->[1] = $1;  # File name
+        $e->[2] = $2;  # Line number
+      }
+    }
+  }
+}
+
+# Print source-listing for one routine
+sub PrintSource {
+  my $prog = shift;
+  my $offset = shift;
+  my $routine = shift;
+  my $flat = shift;
+  my $cumulative = shift;
+  my $start_addr = shift;
+  my $end_addr = shift;
+  my $html = shift;
+  my $output = shift;
+
+  # Disassemble all instructions (just to get line numbers)
+  my @instructions = Disassemble($prog, $offset, $start_addr, $end_addr);
+  GetTopLevelLineNumbers($prog, $offset, \@instructions);
+
+  # Hack 1: assume that the first source file encountered in the
+  # disassembly contains the routine
+  my $filename = undef;
+  for (my $i = 0; $i <= $#instructions; $i++) {
+    if ($instructions[$i]->[2] >= 0) {
+      $filename = $instructions[$i]->[1];
+      last;
+    }
+  }
+  if (!defined($filename)) {
+    print STDERR "no filename found in $routine\n";
+    return 0;
+  }
+
+  # Hack 2: assume that the largest line number from $filename is the
+  # end of the procedure.  This is typically safe since if P1 contains
+  # an inlined call to P2, then P2 usually occurs earlier in the
+  # source file.  If this does not work, we might have to compute a
+  # density profile or just print all regions we find.
+  my $lastline = 0;
+  for (my $i = 0; $i <= $#instructions; $i++) {
+    my $f = $instructions[$i]->[1];
+    my $l = $instructions[$i]->[2];
+    if (($f eq $filename) && ($l > $lastline)) {
+      $lastline = $l;
+    }
+  }
+
+  # Hack 3: assume the first source location from "filename" is the start of
+  # the source code.
+  my $firstline = 1;
+  for (my $i = 0; $i <= $#instructions; $i++) {
+    if ($instructions[$i]->[1] eq $filename) {
+      $firstline = $instructions[$i]->[2];
+      last;
+    }
+  }
+
+  # Hack 4: Extend last line forward until its indentation is less than
+  # the indentation we saw on $firstline
+  my $oldlastline = $lastline;
+  {
+    if (!open(FILE, "<$filename")) {
+      print STDERR "$filename: $!\n";
+      return 0;
+    }
+    my $l = 0;
+    my $first_indentation = -1;
+    while (<FILE>) {
+      s/\r//g;         # turn windows-looking lines into unix-looking lines
+      $l++;
+      my $indent = Indentation($_);
+      if ($l >= $firstline) {
+        if ($first_indentation < 0 && $indent >= 0) {
+          $first_indentation = $indent;
+          last if ($first_indentation == 0);
+        }
+      }
+      if ($l >= $lastline && $indent >= 0) {
+        if ($indent >= $first_indentation) {
+          $lastline = $l+1;
+        } else {
+          last;
+        }
+      }
+    }
+    close(FILE);
+  }
+
+  # Assign all samples to the range $firstline,$lastline,
+  # Hack 4: If an instruction does not occur in the range, its samples
+  # are moved to the next instruction that occurs in the range.
+  my $samples1 = {};        # Map from line number to flat count
+  my $samples2 = {};        # Map from line number to cumulative count
+  my $running1 = 0;         # Unassigned flat counts
+  my $running2 = 0;         # Unassigned cumulative counts
+  my $total1 = 0;           # Total flat counts
+  my $total2 = 0;           # Total cumulative counts
+  my %disasm = ();          # Map from line number to disassembly
+  my $running_disasm = "";  # Unassigned disassembly
+  my $skip_marker = "---\n";
+  if ($html) {
+    $skip_marker = "";
+    for (my $l = $firstline; $l <= $lastline; $l++) {
+      $disasm{$l} = "";
+    }
+  }
+  my $last_dis_filename = '';
+  my $last_dis_linenum = -1;
+  my $last_touched_line = -1;  # To detect gaps in disassembly for a line
+  foreach my $e (@instructions) {
+    # Add up counts for all address that fall inside this instruction
+    my $c1 = 0;
+    my $c2 = 0;
+    for (my $a = $e->[0]; $a lt $e->[4]; $a = AddressInc($a)) {
+      $c1 += GetEntry($flat, $a);
+      $c2 += GetEntry($cumulative, $a);
+    }
+
+    if ($html) {
+      my $dis = sprintf("      %6s %6s \t\t%8s: %s ",
+                        HtmlPrintNumber($c1),
+                        HtmlPrintNumber($c2),
+                        UnparseAddress($offset, $e->[0]),
+                        CleanDisassembly($e->[3]));
+      
+      # Append the most specific source line associated with this instruction
+      if (length($dis) < 80) { $dis .= (' ' x (80 - length($dis))) };
+      $dis = HtmlEscape($dis);
+      my $f = $e->[5];
+      my $l = $e->[6];
+      if ($f ne $last_dis_filename) {
+        $dis .= sprintf("<span class=disasmloc>%s:%d</span>", 
+                        HtmlEscape(CleanFileName($f)), $l);
+      } elsif ($l ne $last_dis_linenum) {
+        # De-emphasize the unchanged file name portion
+        $dis .= sprintf("<span class=unimportant>%s</span>" .
+                        "<span class=disasmloc>:%d</span>", 
+                        HtmlEscape(CleanFileName($f)), $l);
+      } else {
+        # De-emphasize the entire location
+        $dis .= sprintf("<span class=unimportant>%s:%d</span>", 
+                        HtmlEscape(CleanFileName($f)), $l);
+      }
+      $last_dis_filename = $f;
+      $last_dis_linenum = $l;
+      $running_disasm .= $dis;
+      $running_disasm .= "\n";
+    }
+
+    $running1 += $c1;
+    $running2 += $c2;
+    $total1 += $c1;
+    $total2 += $c2;
+    my $file = $e->[1];
+    my $line = $e->[2];
+    if (($file eq $filename) &&
+        ($line >= $firstline) &&
+        ($line <= $lastline)) {
+      # Assign all accumulated samples to this line
+      AddEntry($samples1, $line, $running1);
+      AddEntry($samples2, $line, $running2);
+      $running1 = 0;
+      $running2 = 0;
+      if ($html) {
+        if ($line != $last_touched_line && $disasm{$line} ne '') {
+          $disasm{$line} .= "\n";
+        }
+        $disasm{$line} .= $running_disasm;
+        $running_disasm = '';
+        $last_touched_line = $line;
+      }
+    }
+  }
+
+  # Assign any leftover samples to $lastline
+  AddEntry($samples1, $lastline, $running1);
+  AddEntry($samples2, $lastline, $running2);
+  if ($html) {
+    if ($lastline != $last_touched_line && $disasm{$lastline} ne '') {
+      $disasm{$lastline} .= "\n";
+    }
+    $disasm{$lastline} .= $running_disasm;
+  }
+
+  if ($html) {
+    printf $output (
+      "<h1>%s</h1>%s\n<pre onClick=\"pprof_toggle_asm()\">\n" .
+      "Total:%6s %6s (flat / cumulative %s)\n",
+      HtmlEscape(ShortFunctionName($routine)),
+      HtmlEscape(CleanFileName($filename)),
+      Unparse($total1),
+      Unparse($total2),
+      Units());
+  } else {
+    printf $output (
+      "ROUTINE ====================== %s in %s\n" .
+      "%6s %6s Total %s (flat / cumulative)\n",
+      ShortFunctionName($routine),
+      CleanFileName($filename),
+      Unparse($total1),
+      Unparse($total2),
+      Units());
+  }
+  if (!open(FILE, "<$filename")) {
+    print STDERR "$filename: $!\n";
+    return 0;
+  }
+  my $l = 0;
+  while (<FILE>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    $l++;
+    if ($l >= $firstline - 5 &&
+        (($l <= $oldlastline + 5) || ($l <= $lastline))) {
+      chop;
+      my $text = $_;
+      if ($l == $firstline) { print $output $skip_marker; }
+      my $n1 = GetEntry($samples1, $l);
+      my $n2 = GetEntry($samples2, $l);
+      if ($html) {
+        # Emit a span that has one of the following classes:
+        #    livesrc -- has samples
+        #    deadsrc -- has disassembly, but with no samples
+        #    nop     -- has no matching disasembly
+        # Also emit an optional span containing disassembly.
+        my $dis = $disasm{$l};
+        my $asm = "";
+        if (defined($dis) && $dis ne '') {
+          $asm = "<span class=\"asm\">" . $dis . "</span>";
+        }
+        my $source_class = (($n1 + $n2 > 0) 
+                            ? "livesrc" 
+                            : (($asm ne "") ? "deadsrc" : "nop"));
+        printf $output (
+          "<span class=\"line\">%5d</span> " .
+          "<span class=\"%s\">%6s %6s %s</span>%s\n",
+          $l, $source_class,
+          HtmlPrintNumber($n1),
+          HtmlPrintNumber($n2),
+          HtmlEscape($text),
+          $asm);
+      } else {
+        printf $output(
+          "%6s %6s %4d: %s\n",
+          UnparseAlt($n1),
+          UnparseAlt($n2),
+          $l,
+          $text);
+      }
+      if ($l == $lastline)  { print $output $skip_marker; }
+    };
+  }
+  close(FILE);
+  if ($html) {
+    print $output "</pre>\n";
+  }
+  return 1;
+}
+
+# Return the source line for the specified file/linenumber.
+# Returns undef if not found.
+sub SourceLine {
+  my $file = shift;
+  my $line = shift;
+
+  # Look in cache
+  if (!defined($main::source_cache{$file})) {
+    if (100 < scalar keys(%main::source_cache)) {
+      # Clear the cache when it gets too big
+      $main::source_cache = ();
+    }
+
+    # Read all lines from the file
+    if (!open(FILE, "<$file")) {
+      print STDERR "$file: $!\n";
+      $main::source_cache{$file} = [];  # Cache the negative result
+      return undef;
+    }
+    my $lines = [];
+    push(@{$lines}, "");        # So we can use 1-based line numbers as indices
+    while (<FILE>) {
+      push(@{$lines}, $_);
+    }
+    close(FILE);
+
+    # Save the lines in the cache
+    $main::source_cache{$file} = $lines;
+  }
+
+  my $lines = $main::source_cache{$file};
+  if (($line < 0) || ($line > $#{$lines})) {
+    return undef;
+  } else {
+    return $lines->[$line];
+  }
+}
+
+# Print disassembly for one routine with interspersed source if available
+sub PrintDisassembledFunction {
+  my $prog = shift;
+  my $offset = shift;
+  my $routine = shift;
+  my $flat = shift;
+  my $cumulative = shift;
+  my $start_addr = shift;
+  my $end_addr = shift;
+  my $total = shift;
+
+  # Disassemble all instructions
+  my @instructions = Disassemble($prog, $offset, $start_addr, $end_addr);
+
+  # Make array of counts per instruction
+  my @flat_count = ();
+  my @cum_count = ();
+  my $flat_total = 0;
+  my $cum_total = 0;
+  foreach my $e (@instructions) {
+    # Add up counts for all address that fall inside this instruction
+    my $c1 = 0;
+    my $c2 = 0;
+    for (my $a = $e->[0]; $a lt $e->[4]; $a = AddressInc($a)) {
+      $c1 += GetEntry($flat, $a);
+      $c2 += GetEntry($cumulative, $a);
+    }
+    push(@flat_count, $c1);
+    push(@cum_count, $c2);
+    $flat_total += $c1;
+    $cum_total += $c2;
+  }
+
+  # Print header with total counts
+  printf("ROUTINE ====================== %s\n" .
+         "%6s %6s %s (flat, cumulative) %.1f%% of total\n",
+         ShortFunctionName($routine),
+         Unparse($flat_total),
+         Unparse($cum_total),
+         Units(),
+         ($cum_total * 100.0) / $total);
+
+  # Process instructions in order
+  my $current_file = "";
+  for (my $i = 0; $i <= $#instructions; ) {
+    my $e = $instructions[$i];
+
+    # Print the new file name whenever we switch files
+    if ($e->[1] ne $current_file) {
+      $current_file = $e->[1];
+      my $fname = $current_file;
+      $fname =~ s|^\./||;   # Trim leading "./"
+
+      # Shorten long file names
+      if (length($fname) >= 58) {
+        $fname = "..." . substr($fname, -55);
+      }
+      printf("-------------------- %s\n", $fname);
+    }
+
+    # TODO: Compute range of lines to print together to deal with
+    # small reorderings.
+    my $first_line = $e->[2];
+    my $last_line = $first_line;
+    my %flat_sum = ();
+    my %cum_sum = ();
+    for (my $l = $first_line; $l <= $last_line; $l++) {
+      $flat_sum{$l} = 0;
+      $cum_sum{$l} = 0;
+    }
+
+    # Find run of instructions for this range of source lines
+    my $first_inst = $i;
+    while (($i <= $#instructions) &&
+           ($instructions[$i]->[2] >= $first_line) &&
+           ($instructions[$i]->[2] <= $last_line)) {
+      $e = $instructions[$i];
+      $flat_sum{$e->[2]} += $flat_count[$i];
+      $cum_sum{$e->[2]} += $cum_count[$i];
+      $i++;
+    }
+    my $last_inst = $i - 1;
+
+    # Print source lines
+    for (my $l = $first_line; $l <= $last_line; $l++) {
+      my $line = SourceLine($current_file, $l);
+      if (!defined($line)) {
+        $line = "?\n";
+        next;
+      } else {
+        $line =~ s/^\s+//;
+      }
+      printf("%6s %6s %5d: %s",
+             UnparseAlt($flat_sum{$l}),
+             UnparseAlt($cum_sum{$l}),
+             $l,
+             $line);
+    }
+
+    # Print disassembly
+    for (my $x = $first_inst; $x <= $last_inst; $x++) {
+      my $e = $instructions[$x];
+      printf("%6s %6s    %8s: %6s\n",
+             UnparseAlt($flat_count[$x]),
+             UnparseAlt($cum_count[$x]),
+             UnparseAddress($offset, $e->[0]),
+             CleanDisassembly($e->[3]));
+    }
+  }
+}
+
+# Print DOT graph
+sub PrintDot {
+  my $prog = shift;
+  my $symbols = shift;
+  my $raw = shift;
+  my $flat = shift;
+  my $cumulative = shift;
+  my $overall_total = shift;
+
+  # Get total
+  my $local_total = TotalProfile($flat);
+  my $nodelimit = int($main::opt_nodefraction * $local_total);
+  my $edgelimit = int($main::opt_edgefraction * $local_total);
+  my $nodecount = $main::opt_nodecount;
+
+  # Find nodes to include
+  my @list = (sort { abs(GetEntry($cumulative, $b)) <=>
+                     abs(GetEntry($cumulative, $a))
+                     || $a cmp $b }
+              keys(%{$cumulative}));
+  my $last = $nodecount - 1;
+  if ($last > $#list) {
+    $last = $#list;
+  }
+  while (($last >= 0) &&
+         (abs(GetEntry($cumulative, $list[$last])) <= $nodelimit)) {
+    $last--;
+  }
+  if ($last < 0) {
+    print STDERR "No nodes to print\n";
+    return 0;
+  }
+
+  if ($nodelimit > 0 || $edgelimit > 0) {
+    printf STDERR ("Dropping nodes with <= %s %s; edges with <= %s abs(%s)\n",
+                   Unparse($nodelimit), Units(),
+                   Unparse($edgelimit), Units());
+  }
+
+  # Open DOT output file
+  my $output;
+  my $escaped_dot = ShellEscape(@DOT);
+  my $escaped_ps2pdf = ShellEscape(@PS2PDF);
+  if ($main::opt_gv) {
+    my $escaped_outfile = ShellEscape(TempName($main::next_tmpfile, "ps"));
+    $output = "| $escaped_dot -Tps2 >$escaped_outfile";
+  } elsif ($main::opt_evince) {
+    my $escaped_outfile = ShellEscape(TempName($main::next_tmpfile, "pdf"));
+    $output = "| $escaped_dot -Tps2 | $escaped_ps2pdf - $escaped_outfile";
+  } elsif ($main::opt_ps) {
+    $output = "| $escaped_dot -Tps2";
+  } elsif ($main::opt_pdf) {
+    $output = "| $escaped_dot -Tps2 | $escaped_ps2pdf - -";
+  } elsif ($main::opt_web || $main::opt_svg) {
+    # We need to post-process the SVG, so write to a temporary file always.
+    my $escaped_outfile = ShellEscape(TempName($main::next_tmpfile, "svg"));
+    $output = "| $escaped_dot -Tsvg >$escaped_outfile";
+  } elsif ($main::opt_gif) {
+    $output = "| $escaped_dot -Tgif";
+  } else {
+    $output = ">&STDOUT";
+  }
+  open(DOT, $output) || error("$output: $!\n");
+
+  # Title
+  printf DOT ("digraph \"%s; %s %s\" {\n",
+              $prog,
+              Unparse($overall_total),
+              Units());
+  if ($main::opt_pdf) {
+    # The output is more printable if we set the page size for dot.
+    printf DOT ("size=\"8,11\"\n");
+  }
+  printf DOT ("node [width=0.375,height=0.25];\n");
+
+  # Print legend
+  printf DOT ("Legend [shape=box,fontsize=24,shape=plaintext," .
+              "label=\"%s\\l%s\\l%s\\l%s\\l%s\\l\"];\n",
+              $prog,
+              sprintf("Total %s: %s", Units(), Unparse($overall_total)),
+              sprintf("Focusing on: %s", Unparse($local_total)),
+              sprintf("Dropped nodes with <= %s abs(%s)",
+                      Unparse($nodelimit), Units()),
+              sprintf("Dropped edges with <= %s %s",
+                      Unparse($edgelimit), Units())
+              );
+
+  # Print nodes
+  my %node = ();
+  my $nextnode = 1;
+  foreach my $a (@list[0..$last]) {
+    # Pick font size
+    my $f = GetEntry($flat, $a);
+    my $c = GetEntry($cumulative, $a);
+
+    my $fs = 8;
+    if ($local_total > 0) {
+      $fs = 8 + (50.0 * sqrt(abs($f * 1.0 / $local_total)));
+    }
+
+    $node{$a} = $nextnode++;
+    my $sym = $a;
+    $sym =~ s/\s+/\\n/g;
+    $sym =~ s/::/\\n/g;
+
+    # Extra cumulative info to print for non-leaves
+    my $extra = "";
+    if ($f != $c) {
+      $extra = sprintf("\\rof %s (%s)",
+                       Unparse($c),
+                       Percent($c, $local_total));
+    }
+    my $style = "";
+    if ($main::opt_heapcheck) {
+      if ($f > 0) {
+        # make leak-causing nodes more visible (add a background)
+        $style = ",style=filled,fillcolor=gray"
+      } elsif ($f < 0) {
+        # make anti-leak-causing nodes (which almost never occur)
+        # stand out as well (triple border)
+        $style = ",peripheries=3"
+      }
+    }
+
+    printf DOT ("N%d [label=\"%s\\n%s (%s)%s\\r" .
+                "\",shape=box,fontsize=%.1f%s];\n",
+                $node{$a},
+                $sym,
+                Unparse($f),
+                Percent($f, $local_total),
+                $extra,
+                $fs,
+                $style,
+               );
+  }
+
+  # Get edges and counts per edge
+  my %edge = ();
+  my $n;
+  my $fullname_to_shortname_map = {};
+  FillFullnameToShortnameMap($symbols, $fullname_to_shortname_map);
+  foreach my $k (keys(%{$raw})) {
+    # TODO: omit low %age edges
+    $n = $raw->{$k};
+    my @translated = TranslateStack($symbols, $fullname_to_shortname_map, $k);
+    for (my $i = 1; $i <= $#translated; $i++) {
+      my $src = $translated[$i];
+      my $dst = $translated[$i-1];
+      #next if ($src eq $dst);  # Avoid self-edges?
+      if (exists($node{$src}) && exists($node{$dst})) {
+        my $edge_label = "$src\001$dst";
+        if (!exists($edge{$edge_label})) {
+          $edge{$edge_label} = 0;
+        }
+        $edge{$edge_label} += $n;
+      }
+    }
+  }
+
+  # Print edges (process in order of decreasing counts)
+  my %indegree = ();   # Number of incoming edges added per node so far
+  my %outdegree = ();  # Number of outgoing edges added per node so far
+  foreach my $e (sort { $edge{$b} <=> $edge{$a} } keys(%edge)) {
+    my @x = split(/\001/, $e);
+    $n = $edge{$e};
+
+    # Initialize degree of kept incoming and outgoing edges if necessary
+    my $src = $x[0];
+    my $dst = $x[1];
+    if (!exists($outdegree{$src})) { $outdegree{$src} = 0; }
+    if (!exists($indegree{$dst})) { $indegree{$dst} = 0; }
+
+    my $keep;
+    if ($indegree{$dst} == 0) {
+      # Keep edge if needed for reachability
+      $keep = 1;
+    } elsif (abs($n) <= $edgelimit) {
+      # Drop if we are below --edgefraction
+      $keep = 0;
+    } elsif ($outdegree{$src} >= $main::opt_maxdegree ||
+             $indegree{$dst} >= $main::opt_maxdegree) {
+      # Keep limited number of in/out edges per node
+      $keep = 0;
+    } else {
+      $keep = 1;
+    }
+
+    if ($keep) {
+      $outdegree{$src}++;
+      $indegree{$dst}++;
+
+      # Compute line width based on edge count
+      my $fraction = abs($local_total ? (3 * ($n / $local_total)) : 0);
+      if ($fraction > 1) { $fraction = 1; }
+      my $w = $fraction * 2;
+      if ($w < 1 && ($main::opt_web || $main::opt_svg)) {
+        # SVG output treats line widths < 1 poorly.
+        $w = 1;
+      }
+
+      # Dot sometimes segfaults if given edge weights that are too large, so
+      # we cap the weights at a large value
+      my $edgeweight = abs($n) ** 0.7;
+      if ($edgeweight > 100000) { $edgeweight = 100000; }
+      $edgeweight = int($edgeweight);
+
+      my $style = sprintf("setlinewidth(%f)", $w);
+      if ($x[1] =~ m/\(inline\)/) {
+        $style .= ",dashed";
+      }
+
+      # Use a slightly squashed function of the edge count as the weight
+      printf DOT ("N%s -> N%s [label=%s, weight=%d, style=\"%s\"];\n",
+                  $node{$x[0]},
+                  $node{$x[1]},
+                  Unparse($n),
+                  $edgeweight,
+                  $style);
+    }
+  }
+
+  print DOT ("}\n");
+  close(DOT);
+
+  if ($main::opt_web || $main::opt_svg) {
+    # Rewrite SVG to be more usable inside web browser.
+    RewriteSvg(TempName($main::next_tmpfile, "svg"));
+  }
+
+  return 1;
+}
+
+sub RewriteSvg {
+  my $svgfile = shift;
+
+  open(SVG, $svgfile) || die "open temp svg: $!";
+  my @svg = <SVG>;
+  close(SVG);
+  unlink $svgfile;
+  my $svg = join('', @svg);
+
+  # Dot's SVG output is
+  #
+  #    <svg width="___" height="___"
+  #     viewBox="___" xmlns=...>
+  #    <g id="graph0" transform="...">
+  #    ...
+  #    </g>
+  #    </svg>
+  #
+  # Change it to
+  #
+  #    <svg width="100%" height="100%"
+  #     xmlns=...>
+  #    $svg_javascript
+  #    <g id="viewport" transform="translate(0,0)">
+  #    <g id="graph0" transform="...">
+  #    ...
+  #    </g>
+  #    </g>
+  #    </svg>
+
+  # Fix width, height; drop viewBox.
+  $svg =~ s/(?s)<svg width="[^"]+" height="[^"]+"(.*?)viewBox="[^"]+"/<svg width="100%" height="100%"$1/;
+
+  # Insert script, viewport <g> above first <g>
+  my $svg_javascript = SvgJavascript();
+  my $viewport = "<g id=\"viewport\" transform=\"translate(0,0)\">\n";
+  $svg =~ s/<g id="graph\d"/$svg_javascript$viewport$&/;
+
+  # Insert final </g> above </svg>.
+  $svg =~ s/(.*)(<\/svg>)/$1<\/g>$2/;
+  $svg =~ s/<g id="graph\d"(.*?)/<g id="viewport"$1/;
+
+  if ($main::opt_svg) {
+    # --svg: write to standard output.
+    print $svg;
+  } else {
+    # Write back to temporary file.
+    open(SVG, ">$svgfile") || die "open $svgfile: $!";
+    print SVG $svg;
+    close(SVG);
+  }
+}
+
+sub SvgJavascript {
+  return <<'EOF';
+<script type="text/ecmascript"><![CDATA[
+// SVGPan
+// http://www.cyberz.org/blog/2009/12/08/svgpan-a-javascript-svg-panzoomdrag-library/
+// Local modification: if(true || ...) below to force panning, never moving.
+
+/**
+ *  SVGPan library 1.2
+ * ====================
+ *
+ * Given an unique existing element with id "viewport", including the
+ * the library into any SVG adds the following capabilities:
+ *
+ *  - Mouse panning
+ *  - Mouse zooming (using the wheel)
+ *  - Object dargging
+ *
+ * Known issues:
+ *
+ *  - Zooming (while panning) on Safari has still some issues
+ *
+ * Releases:
+ *
+ * 1.2, Sat Mar 20 08:42:50 GMT 2010, Zeng Xiaohui
+ *	Fixed a bug with browser mouse handler interaction
+ *
+ * 1.1, Wed Feb  3 17:39:33 GMT 2010, Zeng Xiaohui
+ *	Updated the zoom code to support the mouse wheel on Safari/Chrome
+ *
+ * 1.0, Andrea Leofreddi
+ *	First release
+ *
+ * This code is licensed under the following BSD license:
+ *
+ * Copyright 2009-2010 Andrea Leofreddi <a.leofreddi@itcharm.com>. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY Andrea Leofreddi ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL Andrea Leofreddi OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of Andrea Leofreddi.
+ */
+
+var root = document.documentElement;
+
+var state = 'none', stateTarget, stateOrigin, stateTf;
+
+setupHandlers(root);
+
+/**
+ * Register handlers
+ */
+function setupHandlers(root){
+	setAttributes(root, {
+		"onmouseup" : "add(evt)",
+		"onmousedown" : "handleMouseDown(evt)",
+		"onmousemove" : "handleMouseMove(evt)",
+		"onmouseup" : "handleMouseUp(evt)",
+		//"onmouseout" : "handleMouseUp(evt)", // Decomment this to stop the pan functionality when dragging out of the SVG element
+	});
+
+	if(navigator.userAgent.toLowerCase().indexOf('webkit') >= 0)
+		window.addEventListener('mousewheel', handleMouseWheel, false); // Chrome/Safari
+	else
+		window.addEventListener('DOMMouseScroll', handleMouseWheel, false); // Others
+
+	var g = svgDoc.getElementById("svg");
+	g.width = "100%";
+	g.height = "100%";
+}
+
+/**
+ * Instance an SVGPoint object with given event coordinates.
+ */
+function getEventPoint(evt) {
+	var p = root.createSVGPoint();
+
+	p.x = evt.clientX;
+	p.y = evt.clientY;
+
+	return p;
+}
+
+/**
+ * Sets the current transform matrix of an element.
+ */
+function setCTM(element, matrix) {
+	var s = "matrix(" + matrix.a + "," + matrix.b + "," + matrix.c + "," + matrix.d + "," + matrix.e + "," + matrix.f + ")";
+
+	element.setAttribute("transform", s);
+}
+
+/**
+ * Dumps a matrix to a string (useful for debug).
+ */
+function dumpMatrix(matrix) {
+	var s = "[ " + matrix.a + ", " + matrix.c + ", " + matrix.e + "\n  " + matrix.b + ", " + matrix.d + ", " + matrix.f + "\n  0, 0, 1 ]";
+
+	return s;
+}
+
+/**
+ * Sets attributes of an element.
+ */
+function setAttributes(element, attributes){
+	for (i in attributes)
+		element.setAttributeNS(null, i, attributes[i]);
+}
+
+/**
+ * Handle mouse move event.
+ */
+function handleMouseWheel(evt) {
+	if(evt.preventDefault)
+		evt.preventDefault();
+
+	evt.returnValue = false;
+
+	var svgDoc = evt.target.ownerDocument;
+
+	var delta;
+
+	if(evt.wheelDelta)
+		delta = evt.wheelDelta / 3600; // Chrome/Safari
+	else
+		delta = evt.detail / -90; // Mozilla
+
+	var z = 1 + delta; // Zoom factor: 0.9/1.1
+
+	var g = svgDoc.getElementById("viewport");
+
+	var p = getEventPoint(evt);
+
+	p = p.matrixTransform(g.getCTM().inverse());
+
+	// Compute new scale matrix in current mouse position
+	var k = root.createSVGMatrix().translate(p.x, p.y).scale(z).translate(-p.x, -p.y);
+
+        setCTM(g, g.getCTM().multiply(k));
+
+	stateTf = stateTf.multiply(k.inverse());
+}
+
+/**
+ * Handle mouse move event.
+ */
+function handleMouseMove(evt) {
+	if(evt.preventDefault)
+		evt.preventDefault();
+
+	evt.returnValue = false;
+
+	var svgDoc = evt.target.ownerDocument;
+
+	var g = svgDoc.getElementById("viewport");
+
+	if(state == 'pan') {
+		// Pan mode
+		var p = getEventPoint(evt).matrixTransform(stateTf);
+
+		setCTM(g, stateTf.inverse().translate(p.x - stateOrigin.x, p.y - stateOrigin.y));
+	} else if(state == 'move') {
+		// Move mode
+		var p = getEventPoint(evt).matrixTransform(g.getCTM().inverse());
+
+		setCTM(stateTarget, root.createSVGMatrix().translate(p.x - stateOrigin.x, p.y - stateOrigin.y).multiply(g.getCTM().inverse()).multiply(stateTarget.getCTM()));
+
+		stateOrigin = p;
+	}
+}
+
+/**
+ * Handle click event.
+ */
+function handleMouseDown(evt) {
+	if(evt.preventDefault)
+		evt.preventDefault();
+
+	evt.returnValue = false;
+
+	var svgDoc = evt.target.ownerDocument;
+
+	var g = svgDoc.getElementById("viewport");
+
+	if(true || evt.target.tagName == "svg") {
+		// Pan mode
+		state = 'pan';
+
+		stateTf = g.getCTM().inverse();
+
+		stateOrigin = getEventPoint(evt).matrixTransform(stateTf);
+	} else {
+		// Move mode
+		state = 'move';
+
+		stateTarget = evt.target;
+
+		stateTf = g.getCTM().inverse();
+
+		stateOrigin = getEventPoint(evt).matrixTransform(stateTf);
+	}
+}
+
+/**
+ * Handle mouse button release event.
+ */
+function handleMouseUp(evt) {
+	if(evt.preventDefault)
+		evt.preventDefault();
+
+	evt.returnValue = false;
+
+	var svgDoc = evt.target.ownerDocument;
+
+	if(state == 'pan' || state == 'move') {
+		// Quit pan mode
+		state = '';
+	}
+}
+
+]]></script>
+EOF
+}
+
+# Provides a map from fullname to shortname for cases where the
+# shortname is ambiguous.  The symlist has both the fullname and
+# shortname for all symbols, which is usually fine, but sometimes --
+# such as overloaded functions -- two different fullnames can map to
+# the same shortname.  In that case, we use the address of the
+# function to disambiguate the two.  This function fills in a map that
+# maps fullnames to modified shortnames in such cases.  If a fullname
+# is not present in the map, the 'normal' shortname provided by the
+# symlist is the appropriate one to use.
+sub FillFullnameToShortnameMap {
+  my $symbols = shift;
+  my $fullname_to_shortname_map = shift;
+  my $shortnames_seen_once = {};
+  my $shortnames_seen_more_than_once = {};
+
+  foreach my $symlist (values(%{$symbols})) {
+    # TODO(csilvers): deal with inlined symbols too.
+    my $shortname = $symlist->[0];
+    my $fullname = $symlist->[2];
+    if ($fullname !~ /<[0-9a-fA-F]+>$/) {  # fullname doesn't end in an address
+      next;       # the only collisions we care about are when addresses differ
+    }
+    if (defined($shortnames_seen_once->{$shortname}) &&
+        $shortnames_seen_once->{$shortname} ne $fullname) {
+      $shortnames_seen_more_than_once->{$shortname} = 1;
+    } else {
+      $shortnames_seen_once->{$shortname} = $fullname;
+    }
+  }
+
+  foreach my $symlist (values(%{$symbols})) {
+    my $shortname = $symlist->[0];
+    my $fullname = $symlist->[2];
+    # TODO(csilvers): take in a list of addresses we care about, and only
+    # store in the map if $symlist->[1] is in that list.  Saves space.
+    next if defined($fullname_to_shortname_map->{$fullname});
+    if (defined($shortnames_seen_more_than_once->{$shortname})) {
+      if ($fullname =~ /<0*([^>]*)>$/) {   # fullname has address at end of it
+        $fullname_to_shortname_map->{$fullname} = "$shortname\@$1";
+      }
+    }
+  }
+}
+
+# Return a small number that identifies the argument.
+# Multiple calls with the same argument will return the same number.
+# Calls with different arguments will return different numbers.
+sub ShortIdFor {
+  my $key = shift;
+  my $id = $main::uniqueid{$key};
+  if (!defined($id)) {
+    $id = keys(%main::uniqueid) + 1;
+    $main::uniqueid{$key} = $id;
+  }
+  return $id;
+}
+
+# Translate a stack of addresses into a stack of symbols
+sub TranslateStack {
+  my $symbols = shift;
+  my $fullname_to_shortname_map = shift;
+  my $k = shift;
+
+  my @addrs = split(/\n/, $k);
+  my @result = ();
+  for (my $i = 0; $i <= $#addrs; $i++) {
+    my $a = $addrs[$i];
+
+    # Skip large addresses since they sometimes show up as fake entries on RH9
+    if (length($a) > 8 && $a gt "7fffffffffffffff") {
+      next;
+    }
+
+    if ($main::opt_disasm || $main::opt_list) {
+      # We want just the address for the key
+      push(@result, $a);
+      next;
+    }
+
+    my $symlist = $symbols->{$a};
+    if (!defined($symlist)) {
+      $symlist = [$a, "", $a];
+    }
+
+    # We can have a sequence of symbols for a particular entry
+    # (more than one symbol in the case of inlining).  Callers
+    # come before callees in symlist, so walk backwards since
+    # the translated stack should contain callees before callers.
+    for (my $j = $#{$symlist}; $j >= 2; $j -= 3) {
+      my $func = $symlist->[$j-2];
+      my $fileline = $symlist->[$j-1];
+      my $fullfunc = $symlist->[$j];
+      if (defined($fullname_to_shortname_map->{$fullfunc})) {
+        $func = $fullname_to_shortname_map->{$fullfunc};
+      }
+      if ($j > 2) {
+        $func = "$func (inline)";
+      }
+
+      # Do not merge nodes corresponding to Callback::Run since that
+      # causes confusing cycles in dot display.  Instead, we synthesize
+      # a unique name for this frame per caller.
+      if ($func =~ m/Callback.*::Run$/) {
+        my $caller = ($i > 0) ? $addrs[$i-1] : 0;
+        $func = "Run#" . ShortIdFor($caller);
+      }
+
+      if ($main::opt_addresses) {
+        push(@result, "$a $func $fileline");
+      } elsif ($main::opt_lines) {
+        if ($func eq '??' && $fileline eq '??:0') {
+          push(@result, "$a");
+        } else {
+          push(@result, "$func $fileline");
+        }
+      } elsif ($main::opt_functions) {
+        if ($func eq '??') {
+          push(@result, "$a");
+        } else {
+          push(@result, $func);
+        }
+      } elsif ($main::opt_files) {
+        if ($fileline eq '??:0' || $fileline eq '') {
+          push(@result, "$a");
+        } else {
+          my $f = $fileline;
+          $f =~ s/:\d+$//;
+          push(@result, $f);
+        }
+      } else {
+        push(@result, $a);
+        last;  # Do not print inlined info
+      }
+    }
+  }
+
+  # print join(",", @addrs), " => ", join(",", @result), "\n";
+  return @result;
+}
+
+# Generate percent string for a number and a total
+sub Percent {
+  my $num = shift;
+  my $tot = shift;
+  if ($tot != 0) {
+    return sprintf("%.1f%%", $num * 100.0 / $tot);
+  } else {
+    return ($num == 0) ? "nan" : (($num > 0) ? "+inf" : "-inf");
+  }
+}
+
+# Generate pretty-printed form of number
+sub Unparse {
+  my $num = shift;
+  if ($main::profile_type eq 'heap' || $main::profile_type eq 'growth') {
+    if ($main::opt_inuse_objects || $main::opt_alloc_objects) {
+      return sprintf("%d", $num);
+    } else {
+      if ($main::opt_show_bytes) {
+        return sprintf("%d", $num);
+      } else {
+        return sprintf("%.1f", $num / 1048576.0);
+      }
+    }
+  } elsif ($main::profile_type eq 'contention' && !$main::opt_contentions) {
+    return sprintf("%.3f", $num / 1e9); # Convert nanoseconds to seconds
+  } else {
+    return sprintf("%d", $num);
+  }
+}
+
+# Alternate pretty-printed form: 0 maps to "."
+sub UnparseAlt {
+  my $num = shift;
+  if ($num == 0) {
+    return ".";
+  } else {
+    return Unparse($num);
+  }
+}
+
+# Alternate pretty-printed form: 0 maps to ""
+sub HtmlPrintNumber {
+  my $num = shift;
+  if ($num == 0) {
+    return "";
+  } else {
+    return Unparse($num);
+  }
+}
+
+# Return output units
+sub Units {
+  if ($main::profile_type eq 'heap' || $main::profile_type eq 'growth') {
+    if ($main::opt_inuse_objects || $main::opt_alloc_objects) {
+      return "objects";
+    } else {
+      if ($main::opt_show_bytes) {
+        return "B";
+      } else {
+        return "MB";
+      }
+    }
+  } elsif ($main::profile_type eq 'contention' && !$main::opt_contentions) {
+    return "seconds";
+  } else {
+    return "samples";
+  }
+}
+
+##### Profile manipulation code #####
+
+# Generate flattened profile:
+# If count is charged to stack [a,b,c,d], in generated profile,
+# it will be charged to [a]
+sub FlatProfile {
+  my $profile = shift;
+  my $result = {};
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @addrs = split(/\n/, $k);
+    if ($#addrs >= 0) {
+      AddEntry($result, $addrs[0], $count);
+    }
+  }
+  return $result;
+}
+
+# Generate cumulative profile:
+# If count is charged to stack [a,b,c,d], in generated profile,
+# it will be charged to [a], [b], [c], [d]
+sub CumulativeProfile {
+  my $profile = shift;
+  my $result = {};
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @addrs = split(/\n/, $k);
+    foreach my $a (@addrs) {
+      AddEntry($result, $a, $count);
+    }
+  }
+  return $result;
+}
+
+# If the second-youngest PC on the stack is always the same, returns
+# that pc.  Otherwise, returns undef.
+sub IsSecondPcAlwaysTheSame {
+  my $profile = shift;
+
+  my $second_pc = undef;
+  foreach my $k (keys(%{$profile})) {
+    my @addrs = split(/\n/, $k);
+    if ($#addrs < 1) {
+      return undef;
+    }
+    if (not defined $second_pc) {
+      $second_pc = $addrs[1];
+    } else {
+      if ($second_pc ne $addrs[1]) {
+        return undef;
+      }
+    }
+  }
+  return $second_pc;
+}
+
+sub ExtractSymbolLocation {
+  my $symbols = shift;
+  my $address = shift;
+  # 'addr2line' outputs "??:0" for unknown locations; we do the
+  # same to be consistent.
+  my $location = "??:0:unknown";
+  if (exists $symbols->{$address}) {
+    my $file = $symbols->{$address}->[1];
+    if ($file eq "?") {
+      $file = "??:0"
+    }
+    $location = $file . ":" . $symbols->{$address}->[0];
+  }
+  return $location;
+}
+
+# Extracts a graph of calls.
+sub ExtractCalls {
+  my $symbols = shift;
+  my $profile = shift;
+
+  my $calls = {};
+  while( my ($stack_trace, $count) = each %$profile ) {
+    my @address = split(/\n/, $stack_trace);
+    my $destination = ExtractSymbolLocation($symbols, $address[0]);
+    AddEntry($calls, $destination, $count);
+    for (my $i = 1; $i <= $#address; $i++) {
+      my $source = ExtractSymbolLocation($symbols, $address[$i]);
+      my $call = "$source -> $destination";
+      AddEntry($calls, $call, $count);
+      $destination = $source;
+    }
+  }
+
+  return $calls;
+}
+
+sub RemoveUninterestingFrames {
+  my $symbols = shift;
+  my $profile = shift;
+
+  # List of function names to skip
+  my %skip = ();
+  my $skip_regexp = 'NOMATCH';
+  if ($main::profile_type eq 'heap' || $main::profile_type eq 'growth') {
+    foreach my $name ('calloc',
+                      'cfree',
+                      'malloc',
+                      'free',
+                      'memalign',
+                      'posix_memalign',
+                      'pvalloc',
+                      'valloc',
+                      'realloc',
+                      'tc_calloc',
+                      'tc_cfree',
+                      'tc_malloc',
+                      'tc_free',
+                      'tc_memalign',
+                      'tc_posix_memalign',
+                      'tc_pvalloc',
+                      'tc_valloc',
+                      'tc_realloc',
+                      'tc_new',
+                      'tc_delete',
+                      'tc_newarray',
+                      'tc_deletearray',
+                      'tc_new_nothrow',
+                      'tc_newarray_nothrow',
+                      'do_malloc',
+                      '::do_malloc',   # new name -- got moved to an unnamed ns
+                      '::do_malloc_or_cpp_alloc',
+                      'DoSampledAllocation',
+                      'simple_alloc::allocate',
+                      '__malloc_alloc_template::allocate',
+                      '__builtin_delete',
+                      '__builtin_new',
+                      '__builtin_vec_delete',
+                      '__builtin_vec_new',
+                      'operator new',
+                      'operator new[]',
+                      # The entry to our memory-allocation routines on OS X
+                      'malloc_zone_malloc',
+                      'malloc_zone_calloc',
+                      'malloc_zone_valloc',
+                      'malloc_zone_realloc',
+                      'malloc_zone_memalign',
+                      'malloc_zone_free',
+                      # These mark the beginning/end of our custom sections
+                      '__start_google_malloc',
+                      '__stop_google_malloc',
+                      '__start_malloc_hook',
+                      '__stop_malloc_hook') {
+      $skip{$name} = 1;
+      $skip{"_" . $name} = 1;   # Mach (OS X) adds a _ prefix to everything
+    }
+    # TODO: Remove TCMalloc once everything has been
+    # moved into the tcmalloc:: namespace and we have flushed
+    # old code out of the system.
+    $skip_regexp = "TCMalloc|^tcmalloc::";
+  } elsif ($main::profile_type eq 'contention') {
+    foreach my $vname ('base::RecordLockProfileData',
+                       'base::SubmitMutexProfileData',
+                       'base::SubmitSpinLockProfileData',
+                       'Mutex::Unlock',
+                       'Mutex::UnlockSlow',
+                       'Mutex::ReaderUnlock',
+                       'MutexLock::~MutexLock',
+                       'SpinLock::Unlock',
+                       'SpinLock::SlowUnlock',
+                       'SpinLockHolder::~SpinLockHolder') {
+      $skip{$vname} = 1;
+    }
+  } elsif ($main::profile_type eq 'cpu') {
+    # Drop signal handlers used for CPU profile collection
+    # TODO(dpeng): this should not be necessary; it's taken
+    # care of by the general 2nd-pc mechanism below.
+    foreach my $name ('ProfileData::Add',           # historical
+                      'ProfileData::prof_handler',  # historical
+                      'CpuProfiler::prof_handler',
+                      '__FRAME_END__',
+                      '__pthread_sighandler',
+                      '__restore') {
+      $skip{$name} = 1;
+    }
+  } else {
+    # Nothing skipped for unknown types
+  }
+
+  if ($main::profile_type eq 'cpu') {
+    # If all the second-youngest program counters are the same,
+    # this STRONGLY suggests that it is an artifact of measurement,
+    # i.e., stack frames pushed by the CPU profiler signal handler.
+    # Hence, we delete them.
+    # (The topmost PC is read from the signal structure, not from
+    # the stack, so it does not get involved.)
+    while (my $second_pc = IsSecondPcAlwaysTheSame($profile)) {
+      my $result = {};
+      my $func = '';
+      if (exists($symbols->{$second_pc})) {
+        $second_pc = $symbols->{$second_pc}->[0];
+      }
+      print STDERR "Removing $second_pc from all stack traces.\n";
+      foreach my $k (keys(%{$profile})) {
+        my $count = $profile->{$k};
+        my @addrs = split(/\n/, $k);
+        splice @addrs, 1, 1;
+        my $reduced_path = join("\n", @addrs);
+        AddEntry($result, $reduced_path, $count);
+      }
+      $profile = $result;
+    }
+  }
+
+  my $result = {};
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @addrs = split(/\n/, $k);
+    my @path = ();
+    foreach my $a (@addrs) {
+      if (exists($symbols->{$a})) {
+        my $func = $symbols->{$a}->[0];
+        if ($skip{$func} || ($func =~ m/$skip_regexp/)) {
+          next;
+        }
+      }
+      push(@path, $a);
+    }
+    my $reduced_path = join("\n", @path);
+    AddEntry($result, $reduced_path, $count);
+  }
+  return $result;
+}
+
+# Reduce profile to granularity given by user
+sub ReduceProfile {
+  my $symbols = shift;
+  my $profile = shift;
+  my $result = {};
+  my $fullname_to_shortname_map = {};
+  FillFullnameToShortnameMap($symbols, $fullname_to_shortname_map);
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @translated = TranslateStack($symbols, $fullname_to_shortname_map, $k);
+    my @path = ();
+    my %seen = ();
+    $seen{''} = 1;      # So that empty keys are skipped
+    foreach my $e (@translated) {
+      # To avoid double-counting due to recursion, skip a stack-trace
+      # entry if it has already been seen
+      if (!$seen{$e}) {
+        $seen{$e} = 1;
+        push(@path, $e);
+      }
+    }
+    my $reduced_path = join("\n", @path);
+    AddEntry($result, $reduced_path, $count);
+  }
+  return $result;
+}
+
+# Does the specified symbol array match the regexp?
+sub SymbolMatches {
+  my $sym = shift;
+  my $re = shift;
+  if (defined($sym)) {
+    for (my $i = 0; $i < $#{$sym}; $i += 3) {
+      if ($sym->[$i] =~ m/$re/ || $sym->[$i+1] =~ m/$re/) {
+        return 1;
+      }
+    }
+  }
+  return 0;
+}
+
+# Focus only on paths involving specified regexps
+sub FocusProfile {
+  my $symbols = shift;
+  my $profile = shift;
+  my $focus = shift;
+  my $result = {};
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @addrs = split(/\n/, $k);
+    foreach my $a (@addrs) {
+      # Reply if it matches either the address/shortname/fileline
+      if (($a =~ m/$focus/) || SymbolMatches($symbols->{$a}, $focus)) {
+        AddEntry($result, $k, $count);
+        last;
+      }
+    }
+  }
+  return $result;
+}
+
+# Focus only on paths not involving specified regexps
+sub IgnoreProfile {
+  my $symbols = shift;
+  my $profile = shift;
+  my $ignore = shift;
+  my $result = {};
+  foreach my $k (keys(%{$profile})) {
+    my $count = $profile->{$k};
+    my @addrs = split(/\n/, $k);
+    my $matched = 0;
+    foreach my $a (@addrs) {
+      # Reply if it matches either the address/shortname/fileline
+      if (($a =~ m/$ignore/) || SymbolMatches($symbols->{$a}, $ignore)) {
+        $matched = 1;
+        last;
+      }
+    }
+    if (!$matched) {
+      AddEntry($result, $k, $count);
+    }
+  }
+  return $result;
+}
+
+# Get total count in profile
+sub TotalProfile {
+  my $profile = shift;
+  my $result = 0;
+  foreach my $k (keys(%{$profile})) {
+    $result += $profile->{$k};
+  }
+  return $result;
+}
+
+# Add A to B
+sub AddProfile {
+  my $A = shift;
+  my $B = shift;
+
+  my $R = {};
+  # add all keys in A
+  foreach my $k (keys(%{$A})) {
+    my $v = $A->{$k};
+    AddEntry($R, $k, $v);
+  }
+  # add all keys in B
+  foreach my $k (keys(%{$B})) {
+    my $v = $B->{$k};
+    AddEntry($R, $k, $v);
+  }
+  return $R;
+}
+
+# Merges symbol maps
+sub MergeSymbols {
+  my $A = shift;
+  my $B = shift;
+
+  my $R = {};
+  foreach my $k (keys(%{$A})) {
+    $R->{$k} = $A->{$k};
+  }
+  if (defined($B)) {
+    foreach my $k (keys(%{$B})) {
+      $R->{$k} = $B->{$k};
+    }
+  }
+  return $R;
+}
+
+
+# Add A to B
+sub AddPcs {
+  my $A = shift;
+  my $B = shift;
+
+  my $R = {};
+  # add all keys in A
+  foreach my $k (keys(%{$A})) {
+    $R->{$k} = 1
+  }
+  # add all keys in B
+  foreach my $k (keys(%{$B})) {
+    $R->{$k} = 1
+  }
+  return $R;
+}
+
+# Subtract B from A
+sub SubtractProfile {
+  my $A = shift;
+  my $B = shift;
+
+  my $R = {};
+  foreach my $k (keys(%{$A})) {
+    my $v = $A->{$k} - GetEntry($B, $k);
+    if ($v < 0 && $main::opt_drop_negative) {
+      $v = 0;
+    }
+    AddEntry($R, $k, $v);
+  }
+  if (!$main::opt_drop_negative) {
+    # Take care of when subtracted profile has more entries
+    foreach my $k (keys(%{$B})) {
+      if (!exists($A->{$k})) {
+        AddEntry($R, $k, 0 - $B->{$k});
+      }
+    }
+  }
+  return $R;
+}
+
+# Get entry from profile; zero if not present
+sub GetEntry {
+  my $profile = shift;
+  my $k = shift;
+  if (exists($profile->{$k})) {
+    return $profile->{$k};
+  } else {
+    return 0;
+  }
+}
+
+# Add entry to specified profile
+sub AddEntry {
+  my $profile = shift;
+  my $k = shift;
+  my $n = shift;
+  if (!exists($profile->{$k})) {
+    $profile->{$k} = 0;
+  }
+  $profile->{$k} += $n;
+}
+
+# Add a stack of entries to specified profile, and add them to the $pcs
+# list.
+sub AddEntries {
+  my $profile = shift;
+  my $pcs = shift;
+  my $stack = shift;
+  my $count = shift;
+  my @k = ();
+
+  foreach my $e (split(/\s+/, $stack)) {
+    my $pc = HexExtend($e);
+    $pcs->{$pc} = 1;
+    push @k, $pc;
+  }
+  AddEntry($profile, (join "\n", @k), $count);
+}
+
+##### Code to profile a server dynamically #####
+
+sub CheckSymbolPage {
+  my $url = SymbolPageURL();
+  my $command = ShellEscape(@URL_FETCHER, $url);
+  open(SYMBOL, "$command |") or error($command);
+  my $line = <SYMBOL>;
+  $line =~ s/\r//g;         # turn windows-looking lines into unix-looking lines
+  close(SYMBOL);
+  unless (defined($line)) {
+    error("$url doesn't exist\n");
+  }
+
+  if ($line =~ /^num_symbols:\s+(\d+)$/) {
+    if ($1 == 0) {
+      error("Stripped binary. No symbols available.\n");
+    }
+  } else {
+    error("Failed to get the number of symbols from $url\n");
+  }
+}
+
+sub IsProfileURL {
+  my $profile_name = shift;
+  if (-f $profile_name) {
+    printf STDERR "Using local file $profile_name.\n";
+    return 0;
+  }
+  return 1;
+}
+
+sub ParseProfileURL {
+  my $profile_name = shift;
+
+  if (!defined($profile_name) || $profile_name eq "") {
+    return ();
+  }
+
+  # Split profile URL - matches all non-empty strings, so no test.
+  $profile_name =~ m,^(https?://)?([^/]+)(.*?)(/|$PROFILES)?$,;
+
+  my $proto = $1 || "http://";
+  my $hostport = $2;
+  my $prefix = $3;
+  my $profile = $4 || "/";
+
+  my $host = $hostport;
+  $host =~ s/:.*//;
+
+  my $baseurl = "$proto$hostport$prefix";
+  return ($host, $baseurl, $profile);
+}
+
+# We fetch symbols from the first profile argument.
+sub SymbolPageURL {
+  my ($host, $baseURL, $path) = ParseProfileURL($main::pfile_args[0]);
+  return "$baseURL$SYMBOL_PAGE";
+}
+
+sub FetchProgramName() {
+  my ($host, $baseURL, $path) = ParseProfileURL($main::pfile_args[0]);
+  my $url = "$baseURL$PROGRAM_NAME_PAGE";
+  my $command_line = ShellEscape(@URL_FETCHER, $url);
+  open(CMDLINE, "$command_line |") or error($command_line);
+  my $cmdline = <CMDLINE>;
+  $cmdline =~ s/\r//g;   # turn windows-looking lines into unix-looking lines
+  close(CMDLINE);
+  error("Failed to get program name from $url\n") unless defined($cmdline);
+  $cmdline =~ s/\x00.+//;  # Remove argv[1] and latters.
+  $cmdline =~ s!\n!!g;  # Remove LFs.
+  return $cmdline;
+}
+
+# Gee, curl's -L (--location) option isn't reliable at least
+# with its 7.12.3 version.  Curl will forget to post data if
+# there is a redirection.  This function is a workaround for
+# curl.  Redirection happens on borg hosts.
+sub ResolveRedirectionForCurl {
+  my $url = shift;
+  my $command_line = ShellEscape(@URL_FETCHER, "--head", $url);
+  open(CMDLINE, "$command_line |") or error($command_line);
+  while (<CMDLINE>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    if (/^Location: (.*)/) {
+      $url = $1;
+    }
+  }
+  close(CMDLINE);
+  return $url;
+}
+
+# Add a timeout flat to URL_FETCHER.  Returns a new list.
+sub AddFetchTimeout {
+  my $timeout = shift;
+  my @fetcher = shift;
+  if (defined($timeout)) {
+    if (join(" ", @fetcher) =~ m/\bcurl -s/) {
+      push(@fetcher, "--max-time", sprintf("%d", $timeout));
+    } elsif (join(" ", @fetcher) =~ m/\brpcget\b/) {
+      push(@fetcher, sprintf("--deadline=%d", $timeout));
+    }
+  }
+  return @fetcher;
+}
+
+# Reads a symbol map from the file handle name given as $1, returning
+# the resulting symbol map.  Also processes variables relating to symbols.
+# Currently, the only variable processed is 'binary=<value>' which updates
+# $main::prog to have the correct program name.
+sub ReadSymbols {
+  my $in = shift;
+  my $map = {};
+  while (<$in>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    # Removes all the leading zeroes from the symbols, see comment below.
+    if (m/^0x0*([0-9a-f]+)\s+(.+)/) {
+      $map->{$1} = $2;
+    } elsif (m/^---/) {
+      last;
+    } elsif (m/^([a-z][^=]*)=(.*)$/ ) {
+      my ($variable, $value) = ($1, $2);
+      for ($variable, $value) {
+        s/^\s+//;
+        s/\s+$//;
+      }
+      if ($variable eq "binary") {
+        if ($main::prog ne $UNKNOWN_BINARY && $main::prog ne $value) {
+          printf STDERR ("Warning: Mismatched binary name '%s', using '%s'.\n",
+                         $main::prog, $value);
+        }
+        $main::prog = $value;
+      } else {
+        printf STDERR ("Ignoring unknown variable in symbols list: " .
+            "'%s' = '%s'\n", $variable, $value);
+      }
+    }
+  }
+  return $map;
+}
+
+# Fetches and processes symbols to prepare them for use in the profile output
+# code.  If the optional 'symbol_map' arg is not given, fetches symbols from
+# $SYMBOL_PAGE for all PC values found in profile.  Otherwise, the raw symbols
+# are assumed to have already been fetched into 'symbol_map' and are simply
+# extracted and processed.
+sub FetchSymbols {
+  my $pcset = shift;
+  my $symbol_map = shift;
+
+  my %seen = ();
+  my @pcs = grep { !$seen{$_}++ } keys(%$pcset);  # uniq
+
+  if (!defined($symbol_map)) {
+    my $post_data = join("+", sort((map {"0x" . "$_"} @pcs)));
+
+    open(POSTFILE, ">$main::tmpfile_sym");
+    print POSTFILE $post_data;
+    close(POSTFILE);
+
+    my $url = SymbolPageURL();
+
+    my $command_line;
+    if (join(" ", @URL_FETCHER) =~ m/\bcurl -s/) {
+      $url = ResolveRedirectionForCurl($url);
+      $command_line = ShellEscape(@URL_FETCHER, "-d", "\@$main::tmpfile_sym",
+                                  $url);
+    } else {
+      $command_line = (ShellEscape(@URL_FETCHER, "--post", $url)
+                       . " < " . ShellEscape($main::tmpfile_sym));
+    }
+    # We use c++filt in case $SYMBOL_PAGE gives us mangled symbols.
+    my $escaped_cppfilt = ShellEscape($obj_tool_map{"c++filt"});
+    open(SYMBOL, "$command_line | $escaped_cppfilt |") or error($command_line);
+    $symbol_map = ReadSymbols(*SYMBOL{IO});
+    close(SYMBOL);
+  }
+
+  my $symbols = {};
+  foreach my $pc (@pcs) {
+    my $fullname;
+    # For 64 bits binaries, symbols are extracted with 8 leading zeroes.
+    # Then /symbol reads the long symbols in as uint64, and outputs
+    # the result with a "0x%08llx" format which get rid of the zeroes.
+    # By removing all the leading zeroes in both $pc and the symbols from
+    # /symbol, the symbols match and are retrievable from the map.
+    my $shortpc = $pc;
+    $shortpc =~ s/^0*//;
+    # Each line may have a list of names, which includes the function
+    # and also other functions it has inlined.  They are separated (in
+    # PrintSymbolizedProfile), by --, which is illegal in function names.
+    my $fullnames;
+    if (defined($symbol_map->{$shortpc})) {
+      $fullnames = $symbol_map->{$shortpc};
+    } else {
+      $fullnames = "0x" . $pc;  # Just use addresses
+    }
+    my $sym = [];
+    $symbols->{$pc} = $sym;
+    foreach my $fullname (split("--", $fullnames)) {
+      my $name = ShortFunctionName($fullname);
+      push(@{$sym}, $name, "?", $fullname);
+    }
+  }
+  return $symbols;
+}
+
+sub BaseName {
+  my $file_name = shift;
+  $file_name =~ s!^.*/!!;  # Remove directory name
+  return $file_name;
+}
+
+sub MakeProfileBaseName {
+  my ($binary_name, $profile_name) = @_;
+  my ($host, $baseURL, $path) = ParseProfileURL($profile_name);
+  my $binary_shortname = BaseName($binary_name);
+  return sprintf("%s.%s.%s",
+                 $binary_shortname, $main::op_time, $host);
+}
+
+sub FetchDynamicProfile {
+  my $binary_name = shift;
+  my $profile_name = shift;
+  my $fetch_name_only = shift;
+  my $encourage_patience = shift;
+
+  if (!IsProfileURL($profile_name)) {
+    return $profile_name;
+  } else {
+    my ($host, $baseURL, $path) = ParseProfileURL($profile_name);
+    if ($path eq "" || $path eq "/") {
+      # Missing type specifier defaults to cpu-profile
+      $path = $PROFILE_PAGE;
+    }
+
+    my $profile_file = MakeProfileBaseName($binary_name, $profile_name);
+
+    my $url = "$baseURL$path";
+    my $fetch_timeout = undef;
+    if ($path =~ m/$PROFILE_PAGE|$PMUPROFILE_PAGE/) {
+      if ($path =~ m/[?]/) {
+        $url .= "&";
+      } else {
+        $url .= "?";
+      }
+      $url .= sprintf("seconds=%d", $main::opt_seconds);
+      $fetch_timeout = $main::opt_seconds * 1.01 + 60;
+    } else {
+      # For non-CPU profiles, we add a type-extension to
+      # the target profile file name.
+      my $suffix = $path;
+      $suffix =~ s,/,.,g;
+      $profile_file .= $suffix;
+    }
+
+    my $profile_dir = $ENV{"PPROF_TMPDIR"} || ($ENV{HOME} . "/pprof");
+    if (! -d $profile_dir) {
+      mkdir($profile_dir)
+          || die("Unable to create profile directory $profile_dir: $!\n");
+    }
+    my $tmp_profile = "$profile_dir/.tmp.$profile_file";
+    my $real_profile = "$profile_dir/$profile_file";
+
+    if ($fetch_name_only > 0) {
+      return $real_profile;
+    }
+
+    my @fetcher = AddFetchTimeout($fetch_timeout, @URL_FETCHER);
+    my $cmd = ShellEscape(@fetcher, $url) . " > " . ShellEscape($tmp_profile);
+    if ($path =~ m/$PROFILE_PAGE|$PMUPROFILE_PAGE|$CENSUSPROFILE_PAGE/){
+      print STDERR "Gathering CPU profile from $url for $main::opt_seconds seconds to\n  ${real_profile}\n";
+      if ($encourage_patience) {
+        print STDERR "Be patient...\n";
+      }
+    } else {
+      print STDERR "Fetching $path profile from $url to\n  ${real_profile}\n";
+    }
+
+    (system($cmd) == 0) || error("Failed to get profile: $cmd: $!\n");
+    (system("mv", $tmp_profile, $real_profile) == 0) || error("Unable to rename profile\n");
+    print STDERR "Wrote profile to $real_profile\n";
+    $main::collected_profile = $real_profile;
+    return $main::collected_profile;
+  }
+}
+
+# Collect profiles in parallel
+sub FetchDynamicProfiles {
+  my $items = scalar(@main::pfile_args);
+  my $levels = log($items) / log(2);
+
+  if ($items == 1) {
+    $main::profile_files[0] = FetchDynamicProfile($main::prog, $main::pfile_args[0], 0, 1);
+  } else {
+    # math rounding issues
+    if ((2 ** $levels) < $items) {
+     $levels++;
+    }
+    my $count = scalar(@main::pfile_args);
+    for (my $i = 0; $i < $count; $i++) {
+      $main::profile_files[$i] = FetchDynamicProfile($main::prog, $main::pfile_args[$i], 1, 0);
+    }
+    print STDERR "Fetching $count profiles, Be patient...\n";
+    FetchDynamicProfilesRecurse($levels, 0, 0);
+    $main::collected_profile = join(" \\\n    ", @main::profile_files);
+  }
+}
+
+# Recursively fork a process to get enough processes
+# collecting profiles
+sub FetchDynamicProfilesRecurse {
+  my $maxlevel = shift;
+  my $level = shift;
+  my $position = shift;
+
+  if (my $pid = fork()) {
+    $position = 0 | ($position << 1);
+    TryCollectProfile($maxlevel, $level, $position);
+    wait;
+  } else {
+    $position = 1 | ($position << 1);
+    TryCollectProfile($maxlevel, $level, $position);
+    cleanup();
+    exit(0);
+  }
+}
+
+# Collect a single profile
+sub TryCollectProfile {
+  my $maxlevel = shift;
+  my $level = shift;
+  my $position = shift;
+
+  if ($level >= ($maxlevel - 1)) {
+    if ($position < scalar(@main::pfile_args)) {
+      FetchDynamicProfile($main::prog, $main::pfile_args[$position], 0, 0);
+    }
+  } else {
+    FetchDynamicProfilesRecurse($maxlevel, $level+1, $position);
+  }
+}
+
+##### Parsing code #####
+
+# Provide a small streaming-read module to handle very large
+# cpu-profile files.  Stream in chunks along a sliding window.
+# Provides an interface to get one 'slot', correctly handling
+# endian-ness differences.  A slot is one 32-bit or 64-bit word
+# (depending on the input profile).  We tell endianness and bit-size
+# for the profile by looking at the first 8 bytes: in cpu profiles,
+# the second slot is always 3 (we'll accept anything that's not 0).
+BEGIN {
+  package CpuProfileStream;
+
+  sub new {
+    my ($class, $file, $fname) = @_;
+    my $self = { file        => $file,
+                 base        => 0,
+                 stride      => 512 * 1024,   # must be a multiple of bitsize/8
+                 slots       => [],
+                 unpack_code => "",           # N for big-endian, V for little
+                 perl_is_64bit => 1,          # matters if profile is 64-bit
+    };
+    bless $self, $class;
+    # Let unittests adjust the stride
+    if ($main::opt_test_stride > 0) {
+      $self->{stride} = $main::opt_test_stride;
+    }
+    # Read the first two slots to figure out bitsize and endianness.
+    my $slots = $self->{slots};
+    my $str;
+    read($self->{file}, $str, 8);
+    # Set the global $address_length based on what we see here.
+    # 8 is 32-bit (8 hexadecimal chars); 16 is 64-bit (16 hexadecimal chars).
+    $address_length = ($str eq (chr(0)x8)) ? 16 : 8;
+    if ($address_length == 8) {
+      if (substr($str, 6, 2) eq chr(0)x2) {
+        $self->{unpack_code} = 'V';  # Little-endian.
+      } elsif (substr($str, 4, 2) eq chr(0)x2) {
+        $self->{unpack_code} = 'N';  # Big-endian
+      } else {
+        ::error("$fname: header size >= 2**16\n");
+      }
+      @$slots = unpack($self->{unpack_code} . "*", $str);
+    } else {
+      # If we're a 64-bit profile, check if we're a 64-bit-capable
+      # perl.  Otherwise, each slot will be represented as a float
+      # instead of an int64, losing precision and making all the
+      # 64-bit addresses wrong.  We won't complain yet, but will
+      # later if we ever see a value that doesn't fit in 32 bits.
+      my $has_q = 0;
+      eval { $has_q = pack("Q", "1") ? 1 : 1; };
+      if (!$has_q) {
+        $self->{perl_is_64bit} = 0;
+      }
+      read($self->{file}, $str, 8);
+      if (substr($str, 4, 4) eq chr(0)x4) {
+        # We'd love to use 'Q', but it's a) not universal, b) not endian-proof.
+        $self->{unpack_code} = 'V';  # Little-endian.
+      } elsif (substr($str, 0, 4) eq chr(0)x4) {
+        $self->{unpack_code} = 'N';  # Big-endian
+      } else {
+        ::error("$fname: header size >= 2**32\n");
+      }
+      my @pair = unpack($self->{unpack_code} . "*", $str);
+      # Since we know one of the pair is 0, it's fine to just add them.
+      @$slots = (0, $pair[0] + $pair[1]);
+    }
+    return $self;
+  }
+
+  # Load more data when we access slots->get(X) which is not yet in memory.
+  sub overflow {
+    my ($self) = @_;
+    my $slots = $self->{slots};
+    $self->{base} += $#$slots + 1;   # skip over data we're replacing
+    my $str;
+    read($self->{file}, $str, $self->{stride});
+    if ($address_length == 8) {      # the 32-bit case
+      # This is the easy case: unpack provides 32-bit unpacking primitives.
+      @$slots = unpack($self->{unpack_code} . "*", $str);
+    } else {
+      # We need to unpack 32 bits at a time and combine.
+      my @b32_values = unpack($self->{unpack_code} . "*", $str);
+      my @b64_values = ();
+      for (my $i = 0; $i < $#b32_values; $i += 2) {
+        # TODO(csilvers): if this is a 32-bit perl, the math below
+        #    could end up in a too-large int, which perl will promote
+        #    to a double, losing necessary precision.  Deal with that.
+        #    Right now, we just die.
+        my ($lo, $hi) = ($b32_values[$i], $b32_values[$i+1]);
+        if ($self->{unpack_code} eq 'N') {    # big-endian
+          ($lo, $hi) = ($hi, $lo);
+        }
+        my $value = $lo + $hi * (2**32);
+        if (!$self->{perl_is_64bit} &&   # check value is exactly represented
+            (($value % (2**32)) != $lo || int($value / (2**32)) != $hi)) {
+          ::error("Need a 64-bit perl to process this 64-bit profile.\n");
+        }
+        push(@b64_values, $value);
+      }
+      @$slots = @b64_values;
+    }
+  }
+
+  # Access the i-th long in the file (logically), or -1 at EOF.
+  sub get {
+    my ($self, $idx) = @_;
+    my $slots = $self->{slots};
+    while ($#$slots >= 0) {
+      if ($idx < $self->{base}) {
+        # The only time we expect a reference to $slots[$i - something]
+        # after referencing $slots[$i] is reading the very first header.
+        # Since $stride > |header|, that shouldn't cause any lookback
+        # errors.  And everything after the header is sequential.
+        print STDERR "Unexpected look-back reading CPU profile";
+        return -1;   # shrug, don't know what better to return
+      } elsif ($idx > $self->{base} + $#$slots) {
+        $self->overflow();
+      } else {
+        return $slots->[$idx - $self->{base}];
+      }
+    }
+    # If we get here, $slots is [], which means we've reached EOF
+    return -1;  # unique since slots is supposed to hold unsigned numbers
+  }
+}
+
+# Reads the top, 'header' section of a profile, and returns the last
+# line of the header, commonly called a 'header line'.  The header
+# section of a profile consists of zero or more 'command' lines that
+# are instructions to pprof, which pprof executes when reading the
+# header.  All 'command' lines start with a %.  After the command
+# lines is the 'header line', which is a profile-specific line that
+# indicates what type of profile it is, and perhaps other global
+# information about the profile.  For instance, here's a header line
+# for a heap profile:
+#   heap profile:     53:    38236 [  5525:  1284029] @ heapprofile
+# For historical reasons, the CPU profile does not contain a text-
+# readable header line.  If the profile looks like a CPU profile,
+# this function returns "".  If no header line could be found, this
+# function returns undef.
+#
+# The following commands are recognized:
+#   %warn -- emit the rest of this line to stderr, prefixed by 'WARNING:'
+#
+# The input file should be in binmode.
+sub ReadProfileHeader {
+  local *PROFILE = shift;
+  my $firstchar = "";
+  my $line = "";
+  read(PROFILE, $firstchar, 1);
+  seek(PROFILE, -1, 1);                    # unread the firstchar
+  if ($firstchar !~ /[[:print:]]/) {       # is not a text character
+    return "";
+  }
+  while (defined($line = <PROFILE>)) {
+    $line =~ s/\r//g;   # turn windows-looking lines into unix-looking lines
+    if ($line =~ /^%warn\s+(.*)/) {        # 'warn' command
+      # Note this matches both '%warn blah\n' and '%warn\n'.
+      print STDERR "WARNING: $1\n";        # print the rest of the line
+    } elsif ($line =~ /^%/) {
+      print STDERR "Ignoring unknown command from profile header: $line";
+    } else {
+      # End of commands, must be the header line.
+      return $line;
+    }
+  }
+  return undef;     # got to EOF without seeing a header line
+}
+
+sub IsSymbolizedProfileFile {
+  my $file_name = shift;
+  if (!(-e $file_name) || !(-r $file_name)) {
+    return 0;
+  }
+  # Check if the file contains a symbol-section marker.
+  open(TFILE, "<$file_name");
+  binmode TFILE;
+  my $firstline = ReadProfileHeader(*TFILE);
+  close(TFILE);
+  if (!$firstline) {
+    return 0;
+  }
+  $SYMBOL_PAGE =~ m,[^/]+$,;    # matches everything after the last slash
+  my $symbol_marker = $&;
+  return $firstline =~ /^--- *$symbol_marker/;
+}
+
+# Parse profile generated by common/profiler.cc and return a reference
+# to a map:
+#      $result->{version}     Version number of profile file
+#      $result->{period}      Sampling period (in microseconds)
+#      $result->{profile}     Profile object
+#      $result->{map}         Memory map info from profile
+#      $result->{pcs}         Hash of all PC values seen, key is hex address
+sub ReadProfile {
+  my $prog = shift;
+  my $fname = shift;
+  my $result;            # return value
+
+  $CONTENTION_PAGE =~ m,[^/]+$,;    # matches everything after the last slash
+  my $contention_marker = $&;
+  $GROWTH_PAGE  =~ m,[^/]+$,;    # matches everything after the last slash
+  my $growth_marker = $&;
+  $SYMBOL_PAGE =~ m,[^/]+$,;    # matches everything after the last slash
+  my $symbol_marker = $&;
+  $PROFILE_PAGE =~ m,[^/]+$,;    # matches everything after the last slash
+  my $profile_marker = $&;
+
+  # Look at first line to see if it is a heap or a CPU profile.
+  # CPU profile may start with no header at all, and just binary data
+  # (starting with \0\0\0\0) -- in that case, don't try to read the
+  # whole firstline, since it may be gigabytes(!) of data.
+  open(PROFILE, "<$fname") || error("$fname: $!\n");
+  binmode PROFILE;      # New perls do UTF-8 processing
+  my $header = ReadProfileHeader(*PROFILE);
+  if (!defined($header)) {   # means "at EOF"
+    error("Profile is empty.\n");
+  }
+
+  my $symbols;
+  if ($header =~ m/^--- *$symbol_marker/o) {
+    # Verify that the user asked for a symbolized profile
+    if (!$main::use_symbolized_profile) {
+      # we have both a binary and symbolized profiles, abort
+      error("FATAL ERROR: Symbolized profile\n   $fname\ncannot be used with " .
+            "a binary arg. Try again without passing\n   $prog\n");
+    }
+    # Read the symbol section of the symbolized profile file.
+    $symbols = ReadSymbols(*PROFILE{IO});
+    # Read the next line to get the header for the remaining profile.
+    $header = ReadProfileHeader(*PROFILE) || "";
+  }
+
+  $main::profile_type = '';
+  if ($header =~ m/^heap profile:.*$growth_marker/o) {
+    $main::profile_type = 'growth';
+    $result =  ReadHeapProfile($prog, *PROFILE, $header);
+  } elsif ($header =~ m/^heap profile:/) {
+    $main::profile_type = 'heap';
+    $result =  ReadHeapProfile($prog, *PROFILE, $header);
+  } elsif ($header =~ m/^--- *$contention_marker/o) {
+    $main::profile_type = 'contention';
+    $result = ReadSynchProfile($prog, *PROFILE);
+  } elsif ($header =~ m/^--- *Stacks:/) {
+    print STDERR
+      "Old format contention profile: mistakenly reports " .
+      "condition variable signals as lock contentions.\n";
+    $main::profile_type = 'contention';
+    $result = ReadSynchProfile($prog, *PROFILE);
+  } elsif ($header =~ m/^--- *$profile_marker/) {
+    # the binary cpu profile data starts immediately after this line
+    $main::profile_type = 'cpu';
+    $result = ReadCPUProfile($prog, $fname, *PROFILE);
+  } else {
+    if (defined($symbols)) {
+      # a symbolized profile contains a format we don't recognize, bail out
+      error("$fname: Cannot recognize profile section after symbols.\n");
+    }
+    # no ascii header present -- must be a CPU profile
+    $main::profile_type = 'cpu';
+    $result = ReadCPUProfile($prog, $fname, *PROFILE);
+  }
+
+  close(PROFILE);
+
+  # if we got symbols along with the profile, return those as well
+  if (defined($symbols)) {
+    $result->{symbols} = $symbols;
+  }
+
+  return $result;
+}
+
+# Subtract one from caller pc so we map back to call instr.
+# However, don't do this if we're reading a symbolized profile
+# file, in which case the subtract-one was done when the file
+# was written.
+#
+# We apply the same logic to all readers, though ReadCPUProfile uses an
+# independent implementation.
+sub FixCallerAddresses {
+  my $stack = shift;
+  if ($main::use_symbolized_profile) {
+    return $stack;
+  } else {
+    $stack =~ /(\s)/;
+    my $delimiter = $1;
+    my @addrs = split(' ', $stack);
+    my @fixedaddrs;
+    $#fixedaddrs = $#addrs;
+    if ($#addrs >= 0) {
+      $fixedaddrs[0] = $addrs[0];
+    }
+    for (my $i = 1; $i <= $#addrs; $i++) {
+      $fixedaddrs[$i] = AddressSub($addrs[$i], "0x1");
+    }
+    return join $delimiter, @fixedaddrs;
+  }
+}
+
+# CPU profile reader
+sub ReadCPUProfile {
+  my $prog = shift;
+  my $fname = shift;       # just used for logging
+  local *PROFILE = shift;
+  my $version;
+  my $period;
+  my $i;
+  my $profile = {};
+  my $pcs = {};
+
+  # Parse string into array of slots.
+  my $slots = CpuProfileStream->new(*PROFILE, $fname);
+
+  # Read header.  The current header version is a 5-element structure
+  # containing:
+  #   0: header count (always 0)
+  #   1: header "words" (after this one: 3)
+  #   2: format version (0)
+  #   3: sampling period (usec)
+  #   4: unused padding (always 0)
+  if ($slots->get(0) != 0 ) {
+    error("$fname: not a profile file, or old format profile file\n");
+  }
+  $i = 2 + $slots->get(1);
+  $version = $slots->get(2);
+  $period = $slots->get(3);
+  # Do some sanity checking on these header values.
+  if ($version > (2**32) || $period > (2**32) || $i > (2**32) || $i < 5) {
+    error("$fname: not a profile file, or corrupted profile file\n");
+  }
+
+  # Parse profile
+  while ($slots->get($i) != -1) {
+    my $n = $slots->get($i++);
+    my $d = $slots->get($i++);
+    if ($d > (2**16)) {  # TODO(csilvers): what's a reasonable max-stack-depth?
+      my $addr = sprintf("0%o", $i * ($address_length == 8 ? 4 : 8));
+      print STDERR "At index $i (address $addr):\n";
+      error("$fname: stack trace depth >= 2**32\n");
+    }
+    if ($slots->get($i) == 0) {
+      # End of profile data marker
+      $i += $d;
+      last;
+    }
+
+    # Make key out of the stack entries
+    my @k = ();
+    for (my $j = 0; $j < $d; $j++) {
+      my $pc = $slots->get($i+$j);
+      # Subtract one from caller pc so we map back to call instr.
+      # However, don't do this if we're reading a symbolized profile
+      # file, in which case the subtract-one was done when the file
+      # was written.
+      if ($j > 0 && !$main::use_symbolized_profile) {
+        $pc--;
+      }
+      $pc = sprintf("%0*x", $address_length, $pc);
+      $pcs->{$pc} = 1;
+      push @k, $pc;
+    }
+
+    AddEntry($profile, (join "\n", @k), $n);
+    $i += $d;
+  }
+
+  # Parse map
+  my $map = '';
+  seek(PROFILE, $i * 4, 0);
+  read(PROFILE, $map, (stat PROFILE)[7]);
+
+  my $r = {};
+  $r->{version} = $version;
+  $r->{period} = $period;
+  $r->{profile} = $profile;
+  $r->{libs} = ParseLibraries($prog, $map, $pcs);
+  $r->{pcs} = $pcs;
+
+  return $r;
+}
+
+sub ReadHeapProfile {
+  my $prog = shift;
+  local *PROFILE = shift;
+  my $header = shift;
+
+  my $index = 1;
+  if ($main::opt_inuse_space) {
+    $index = 1;
+  } elsif ($main::opt_inuse_objects) {
+    $index = 0;
+  } elsif ($main::opt_alloc_space) {
+    $index = 3;
+  } elsif ($main::opt_alloc_objects) {
+    $index = 2;
+  }
+
+  # Find the type of this profile.  The header line looks like:
+  #    heap profile:   1246:  8800744 [  1246:  8800744] @ <heap-url>/266053
+  # There are two pairs <count: size>, the first inuse objects/space, and the
+  # second allocated objects/space.  This is followed optionally by a profile
+  # type, and if that is present, optionally by a sampling frequency.
+  # For remote heap profiles (v1):
+  # The interpretation of the sampling frequency is that the profiler, for
+  # each sample, calculates a uniformly distributed random integer less than
+  # the given value, and records the next sample after that many bytes have
+  # been allocated.  Therefore, the expected sample interval is half of the
+  # given frequency.  By default, if not specified, the expected sample
+  # interval is 128KB.  Only remote-heap-page profiles are adjusted for
+  # sample size.
+  # For remote heap profiles (v2):
+  # The sampling frequency is the rate of a Poisson process. This means that
+  # the probability of sampling an allocation of size X with sampling rate Y
+  # is 1 - exp(-X/Y)
+  # For version 2, a typical header line might look like this:
+  # heap profile:   1922: 127792360 [  1922: 127792360] @ <heap-url>_v2/524288
+  # the trailing number (524288) is the sampling rate. (Version 1 showed
+  # double the 'rate' here)
+  my $sampling_algorithm = 0;
+  my $sample_adjustment = 0;
+  chomp($header);
+  my $type = "unknown";
+  if ($header =~ m"^heap profile:\s*(\d+):\s+(\d+)\s+\[\s*(\d+):\s+(\d+)\](\s*@\s*([^/]*)(/(\d+))?)?") {
+    if (defined($6) && ($6 ne '')) {
+      $type = $6;
+      my $sample_period = $8;
+      # $type is "heapprofile" for profiles generated by the
+      # heap-profiler, and either "heap" or "heap_v2" for profiles
+      # generated by sampling directly within tcmalloc.  It can also
+      # be "growth" for heap-growth profiles.  The first is typically
+      # found for profiles generated locally, and the others for
+      # remote profiles.
+      if (($type eq "heapprofile") || ($type !~ /heap/) ) {
+        # No need to adjust for the sampling rate with heap-profiler-derived data
+        $sampling_algorithm = 0;
+      } elsif ($type =~ /_v2/) {
+        $sampling_algorithm = 2;     # version 2 sampling
+        if (defined($sample_period) && ($sample_period ne '')) {
+          $sample_adjustment = int($sample_period);
+        }
+      } else {
+        $sampling_algorithm = 1;     # version 1 sampling
+        if (defined($sample_period) && ($sample_period ne '')) {
+          $sample_adjustment = int($sample_period)/2;
+        }
+      }
+    } else {
+      # We detect whether or not this is a remote-heap profile by checking
+      # that the total-allocated stats ($n2,$s2) are exactly the
+      # same as the in-use stats ($n1,$s1).  It is remotely conceivable
+      # that a non-remote-heap profile may pass this check, but it is hard
+      # to imagine how that could happen.
+      # In this case it's so old it's guaranteed to be remote-heap version 1.
+      my ($n1, $s1, $n2, $s2) = ($1, $2, $3, $4);
+      if (($n1 == $n2) && ($s1 == $s2)) {
+        # This is likely to be a remote-heap based sample profile
+        $sampling_algorithm = 1;
+      }
+    }
+  }
+
+  if ($sampling_algorithm > 0) {
+    # For remote-heap generated profiles, adjust the counts and sizes to
+    # account for the sample rate (we sample once every 128KB by default).
+    if ($sample_adjustment == 0) {
+      # Turn on profile adjustment.
+      $sample_adjustment = 128*1024;
+      print STDERR "Adjusting heap profiles for 1-in-128KB sampling rate\n";
+    } else {
+      printf STDERR ("Adjusting heap profiles for 1-in-%d sampling rate\n",
+                     $sample_adjustment);
+    }
+    if ($sampling_algorithm > 1) {
+      # We don't bother printing anything for the original version (version 1)
+      printf STDERR "Heap version $sampling_algorithm\n";
+    }
+  }
+
+  my $profile = {};
+  my $pcs = {};
+  my $map = "";
+
+  while (<PROFILE>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    if (/^MAPPED_LIBRARIES:/) {
+      # Read the /proc/self/maps data
+      while (<PROFILE>) {
+        s/\r//g;         # turn windows-looking lines into unix-looking lines
+        $map .= $_;
+      }
+      last;
+    }
+
+    if (/^--- Memory map:/) {
+      # Read /proc/self/maps data as formatted by DumpAddressMap()
+      my $buildvar = "";
+      while (<PROFILE>) {
+        s/\r//g;         # turn windows-looking lines into unix-looking lines
+        # Parse "build=<dir>" specification if supplied
+        if (m/^\s*build=(.*)\n/) {
+          $buildvar = $1;
+        }
+
+        # Expand "$build" variable if available
+        $_ =~ s/\$build\b/$buildvar/g;
+
+        $map .= $_;
+      }
+      last;
+    }
+
+    # Read entry of the form:
+    #  <count1>: <bytes1> [<count2>: <bytes2>] @ a1 a2 a3 ... an
+    s/^\s*//;
+    s/\s*$//;
+    if (m/^\s*(\d+):\s+(\d+)\s+\[\s*(\d+):\s+(\d+)\]\s+@\s+(.*)$/) {
+      my $stack = $5;
+      my ($n1, $s1, $n2, $s2) = ($1, $2, $3, $4);
+
+      if ($sample_adjustment) {
+        if ($sampling_algorithm == 2) {
+          # Remote-heap version 2
+          # The sampling frequency is the rate of a Poisson process.
+          # This means that the probability of sampling an allocation of
+          # size X with sampling rate Y is 1 - exp(-X/Y)
+          if ($n1 != 0) {
+            my $ratio = (($s1*1.0)/$n1)/($sample_adjustment);
+            my $scale_factor = 1/(1 - exp(-$ratio));
+            $n1 *= $scale_factor;
+            $s1 *= $scale_factor;
+          }
+          if ($n2 != 0) {
+            my $ratio = (($s2*1.0)/$n2)/($sample_adjustment);
+            my $scale_factor = 1/(1 - exp(-$ratio));
+            $n2 *= $scale_factor;
+            $s2 *= $scale_factor;
+          }
+        } else {
+          # Remote-heap version 1
+          my $ratio;
+          $ratio = (($s1*1.0)/$n1)/($sample_adjustment);
+          if ($ratio < 1) {
+            $n1 /= $ratio;
+            $s1 /= $ratio;
+          }
+          $ratio = (($s2*1.0)/$n2)/($sample_adjustment);
+          if ($ratio < 1) {
+            $n2 /= $ratio;
+            $s2 /= $ratio;
+          }
+        }
+      }
+
+      my @counts = ($n1, $s1, $n2, $s2);
+      AddEntries($profile, $pcs, FixCallerAddresses($stack), $counts[$index]);
+    }
+  }
+
+  my $r = {};
+  $r->{version} = "heap";
+  $r->{period} = 1;
+  $r->{profile} = $profile;
+  $r->{libs} = ParseLibraries($prog, $map, $pcs);
+  $r->{pcs} = $pcs;
+  return $r;
+}
+
+sub ReadSynchProfile {
+  my $prog = shift;
+  local *PROFILE = shift;
+  my $header = shift;
+
+  my $map = '';
+  my $profile = {};
+  my $pcs = {};
+  my $sampling_period = 1;
+  my $cyclespernanosec = 2.8;   # Default assumption for old binaries
+  my $seen_clockrate = 0;
+  my $line;
+
+  my $index = 0;
+  if ($main::opt_total_delay) {
+    $index = 0;
+  } elsif ($main::opt_contentions) {
+    $index = 1;
+  } elsif ($main::opt_mean_delay) {
+    $index = 2;
+  }
+
+  while ( $line = <PROFILE> ) {
+    $line =~ s/\r//g;      # turn windows-looking lines into unix-looking lines
+    if ( $line =~ /^\s*(\d+)\s+(\d+) \@\s*(.*?)\s*$/ ) {
+      my ($cycles, $count, $stack) = ($1, $2, $3);
+
+      # Convert cycles to nanoseconds
+      $cycles /= $cyclespernanosec;
+
+      # Adjust for sampling done by application
+      $cycles *= $sampling_period;
+      $count *= $sampling_period;
+
+      my @values = ($cycles, $count, $cycles / $count);
+      AddEntries($profile, $pcs, FixCallerAddresses($stack), $values[$index]);
+
+    } elsif ( $line =~ /^(slow release).*thread \d+  \@\s*(.*?)\s*$/ ||
+              $line =~ /^\s*(\d+) \@\s*(.*?)\s*$/ ) {
+      my ($cycles, $stack) = ($1, $2);
+      if ($cycles !~ /^\d+$/) {
+        next;
+      }
+
+      # Convert cycles to nanoseconds
+      $cycles /= $cyclespernanosec;
+
+      # Adjust for sampling done by application
+      $cycles *= $sampling_period;
+
+      AddEntries($profile, $pcs, FixCallerAddresses($stack), $cycles);
+
+    } elsif ( $line =~ m/^([a-z][^=]*)=(.*)$/ ) {
+      my ($variable, $value) = ($1,$2);
+      for ($variable, $value) {
+        s/^\s+//;
+        s/\s+$//;
+      }
+      if ($variable eq "cycles/second") {
+        $cyclespernanosec = $value / 1e9;
+        $seen_clockrate = 1;
+      } elsif ($variable eq "sampling period") {
+        $sampling_period = $value;
+      } elsif ($variable eq "ms since reset") {
+        # Currently nothing is done with this value in pprof
+        # So we just silently ignore it for now
+      } elsif ($variable eq "discarded samples") {
+        # Currently nothing is done with this value in pprof
+        # So we just silently ignore it for now
+      } else {
+        printf STDERR ("Ignoring unnknown variable in /contention output: " .
+                       "'%s' = '%s'\n",$variable,$value);
+      }
+    } else {
+      # Memory map entry
+      $map .= $line;
+    }
+  }
+
+  if (!$seen_clockrate) {
+    printf STDERR ("No cycles/second entry in profile; Guessing %.1f GHz\n",
+                   $cyclespernanosec);
+  }
+
+  my $r = {};
+  $r->{version} = 0;
+  $r->{period} = $sampling_period;
+  $r->{profile} = $profile;
+  $r->{libs} = ParseLibraries($prog, $map, $pcs);
+  $r->{pcs} = $pcs;
+  return $r;
+}
+
+# Given a hex value in the form "0x1abcd" or "1abcd", return either
+# "0001abcd" or "000000000001abcd", depending on the current (global)
+# address length.
+sub HexExtend {
+  my $addr = shift;
+
+  $addr =~ s/^(0x)?0*//;
+  my $zeros_needed = $address_length - length($addr);
+  if ($zeros_needed < 0) {
+    printf STDERR "Warning: address $addr is longer than address length $address_length\n";
+    return $addr;
+  }
+  return ("0" x $zeros_needed) . $addr;
+}
+
+##### Symbol extraction #####
+
+# Aggressively search the lib_prefix values for the given library
+# If all else fails, just return the name of the library unmodified.
+# If the lib_prefix is "/my/path,/other/path" and $file is "/lib/dir/mylib.so"
+# it will search the following locations in this order, until it finds a file:
+#   /my/path/lib/dir/mylib.so
+#   /other/path/lib/dir/mylib.so
+#   /my/path/dir/mylib.so
+#   /other/path/dir/mylib.so
+#   /my/path/mylib.so
+#   /other/path/mylib.so
+#   /lib/dir/mylib.so              (returned as last resort)
+sub FindLibrary {
+  my $file = shift;
+  my $suffix = $file;
+
+  # Search for the library as described above
+  do {
+    foreach my $prefix (@prefix_list) {
+      my $fullpath = $prefix . $suffix;
+      if (-e $fullpath) {
+        return $fullpath;
+      }
+    }
+  } while ($suffix =~ s|^/[^/]+/|/|);
+  return $file;
+}
+
+# Return path to library with debugging symbols.
+# For libc libraries, the copy in /usr/lib/debug contains debugging symbols
+sub DebuggingLibrary {
+  my $file = shift;
+  if ($file =~ m|^/| && -f "/usr/lib/debug$file") {
+    return "/usr/lib/debug$file";
+  }
+  return undef;
+}
+
+# Parse text section header of a library using objdump
+sub ParseTextSectionHeaderFromObjdump {
+  my $lib = shift;
+
+  my $size = undef;
+  my $vma;
+  my $file_offset;
+  # Get objdump output from the library file to figure out how to
+  # map between mapped addresses and addresses in the library.
+  my $cmd = ShellEscape($obj_tool_map{"objdump"}, "-h", $lib);
+  open(OBJDUMP, "$cmd |") || error("$cmd: $!\n");
+  while (<OBJDUMP>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    # Idx Name          Size      VMA       LMA       File off  Algn
+    #  10 .text         00104b2c  420156f0  420156f0  000156f0  2**4
+    # For 64-bit objects, VMA and LMA will be 16 hex digits, size and file
+    # offset may still be 8.  But AddressSub below will still handle that.
+    my @x = split;
+    if (($#x >= 6) && ($x[1] eq '.text')) {
+      $size = $x[2];
+      $vma = $x[3];
+      $file_offset = $x[5];
+      last;
+    }
+  }
+  close(OBJDUMP);
+
+  if (!defined($size)) {
+    return undef;
+  }
+
+  my $r = {};
+  $r->{size} = $size;
+  $r->{vma} = $vma;
+  $r->{file_offset} = $file_offset;
+
+  return $r;
+}
+
+# Parse text section header of a library using otool (on OS X)
+sub ParseTextSectionHeaderFromOtool {
+  my $lib = shift;
+
+  my $size = undef;
+  my $vma = undef;
+  my $file_offset = undef;
+  # Get otool output from the library file to figure out how to
+  # map between mapped addresses and addresses in the library.
+  my $command = ShellEscape($obj_tool_map{"otool"}, "-l", $lib);
+  open(OTOOL, "$command |") || error("$command: $!\n");
+  my $cmd = "";
+  my $sectname = "";
+  my $segname = "";
+  foreach my $line (<OTOOL>) {
+    $line =~ s/\r//g;      # turn windows-looking lines into unix-looking lines
+    # Load command <#>
+    #       cmd LC_SEGMENT
+    # [...]
+    # Section
+    #   sectname __text
+    #    segname __TEXT
+    #       addr 0x000009f8
+    #       size 0x00018b9e
+    #     offset 2552
+    #      align 2^2 (4)
+    # We will need to strip off the leading 0x from the hex addresses,
+    # and convert the offset into hex.
+    if ($line =~ /Load command/) {
+      $cmd = "";
+      $sectname = "";
+      $segname = "";
+    } elsif ($line =~ /Section/) {
+      $sectname = "";
+      $segname = "";
+    } elsif ($line =~ /cmd (\w+)/) {
+      $cmd = $1;
+    } elsif ($line =~ /sectname (\w+)/) {
+      $sectname = $1;
+    } elsif ($line =~ /segname (\w+)/) {
+      $segname = $1;
+    } elsif (!(($cmd eq "LC_SEGMENT" || $cmd eq "LC_SEGMENT_64") &&
+               $sectname eq "__text" &&
+               $segname eq "__TEXT")) {
+      next;
+    } elsif ($line =~ /\baddr 0x([0-9a-fA-F]+)/) {
+      $vma = $1;
+    } elsif ($line =~ /\bsize 0x([0-9a-fA-F]+)/) {
+      $size = $1;
+    } elsif ($line =~ /\boffset ([0-9]+)/) {
+      $file_offset = sprintf("%016x", $1);
+    }
+    if (defined($vma) && defined($size) && defined($file_offset)) {
+      last;
+    }
+  }
+  close(OTOOL);
+
+  if (!defined($vma) || !defined($size) || !defined($file_offset)) {
+     return undef;
+  }
+
+  my $r = {};
+  $r->{size} = $size;
+  $r->{vma} = $vma;
+  $r->{file_offset} = $file_offset;
+
+  return $r;
+}
+
+sub ParseTextSectionHeader {
+  # obj_tool_map("otool") is only defined if we're in a Mach-O environment
+  if (defined($obj_tool_map{"otool"})) {
+    my $r = ParseTextSectionHeaderFromOtool(@_);
+    if (defined($r)){
+      return $r;
+    }
+  }
+  # If otool doesn't work, or we don't have it, fall back to objdump
+  return ParseTextSectionHeaderFromObjdump(@_);
+}
+
+# Split /proc/pid/maps dump into a list of libraries
+sub ParseLibraries {
+  return if $main::use_symbol_page;  # We don't need libraries info.
+  my $prog = shift;
+  my $map = shift;
+  my $pcs = shift;
+
+  my $result = [];
+  my $h = "[a-f0-9]+";
+  my $zero_offset = HexExtend("0");
+
+  my $buildvar = "";
+  foreach my $l (split("\n", $map)) {
+    if ($l =~ m/^\s*build=(.*)$/) {
+      $buildvar = $1;
+    }
+
+    my $start;
+    my $finish;
+    my $offset;
+    my $lib;
+    if ($l =~ /^($h)-($h)\s+..x.\s+($h)\s+\S+:\S+\s+\d+\s+(\S+\.(so|dll|dylib|bundle)((\.\d+)+\w*(\.\d+){0,3})?)$/i) {
+      # Full line from /proc/self/maps.  Example:
+      #   40000000-40015000 r-xp 00000000 03:01 12845071   /lib/ld-2.3.2.so
+      $start = HexExtend($1);
+      $finish = HexExtend($2);
+      $offset = HexExtend($3);
+      $lib = $4;
+      $lib =~ s|\\|/|g;     # turn windows-style paths into unix-style paths
+    } elsif ($l =~ /^\s*($h)-($h):\s*(\S+\.so(\.\d+)*)/) {
+      # Cooked line from DumpAddressMap.  Example:
+      #   40000000-40015000: /lib/ld-2.3.2.so
+      $start = HexExtend($1);
+      $finish = HexExtend($2);
+      $offset = $zero_offset;
+      $lib = $3;
+    } else {
+      next;
+    }
+
+    # Expand "$build" variable if available
+    $lib =~ s/\$build\b/$buildvar/g;
+
+    $lib = FindLibrary($lib);
+
+    # Check for pre-relocated libraries, which use pre-relocated symbol tables
+    # and thus require adjusting the offset that we'll use to translate
+    # VM addresses into symbol table addresses.
+    # Only do this if we're not going to fetch the symbol table from a
+    # debugging copy of the library.
+    if (!DebuggingLibrary($lib)) {
+      my $text = ParseTextSectionHeader($lib);
+      if (defined($text)) {
+         my $vma_offset = AddressSub($text->{vma}, $text->{file_offset});
+         $offset = AddressAdd($offset, $vma_offset);
+      }
+    }
+
+    push(@{$result}, [$lib, $start, $finish, $offset]);
+  }
+
+  # Append special entry for additional library (not relocated)
+  if ($main::opt_lib ne "") {
+    my $text = ParseTextSectionHeader($main::opt_lib);
+    if (defined($text)) {
+       my $start = $text->{vma};
+       my $finish = AddressAdd($start, $text->{size});
+
+       push(@{$result}, [$main::opt_lib, $start, $finish, $start]);
+    }
+  }
+
+  # Append special entry for the main program.  This covers
+  # 0..max_pc_value_seen, so that we assume pc values not found in one
+  # of the library ranges will be treated as coming from the main
+  # program binary.
+  my $min_pc = HexExtend("0");
+  my $max_pc = $min_pc;          # find the maximal PC value in any sample
+  foreach my $pc (keys(%{$pcs})) {
+    if (HexExtend($pc) gt $max_pc) { $max_pc = HexExtend($pc); }
+  }
+  push(@{$result}, [$prog, $min_pc, $max_pc, $zero_offset]);
+
+  return $result;
+}
+
+# Add two hex addresses of length $address_length.
+# Run pprof --test for unit test if this is changed.
+sub AddressAdd {
+  my $addr1 = shift;
+  my $addr2 = shift;
+  my $sum;
+
+  if ($address_length == 8) {
+    # Perl doesn't cope with wraparound arithmetic, so do it explicitly:
+    $sum = (hex($addr1)+hex($addr2)) % (0x10000000 * 16);
+    return sprintf("%08x", $sum);
+
+  } else {
+    # Do the addition in 7-nibble chunks to trivialize carry handling.
+
+    if ($main::opt_debug and $main::opt_test) {
+      print STDERR "AddressAdd $addr1 + $addr2 = ";
+    }
+
+    my $a1 = substr($addr1,-7);
+    $addr1 = substr($addr1,0,-7);
+    my $a2 = substr($addr2,-7);
+    $addr2 = substr($addr2,0,-7);
+    $sum = hex($a1) + hex($a2);
+    my $c = 0;
+    if ($sum > 0xfffffff) {
+      $c = 1;
+      $sum -= 0x10000000;
+    }
+    my $r = sprintf("%07x", $sum);
+
+    $a1 = substr($addr1,-7);
+    $addr1 = substr($addr1,0,-7);
+    $a2 = substr($addr2,-7);
+    $addr2 = substr($addr2,0,-7);
+    $sum = hex($a1) + hex($a2) + $c;
+    $c = 0;
+    if ($sum > 0xfffffff) {
+      $c = 1;
+      $sum -= 0x10000000;
+    }
+    $r = sprintf("%07x", $sum) . $r;
+
+    $sum = hex($addr1) + hex($addr2) + $c;
+    if ($sum > 0xff) { $sum -= 0x100; }
+    $r = sprintf("%02x", $sum) . $r;
+
+    if ($main::opt_debug and $main::opt_test) { print STDERR "$r\n"; }
+
+    return $r;
+  }
+}
+
+
+# Subtract two hex addresses of length $address_length.
+# Run pprof --test for unit test if this is changed.
+sub AddressSub {
+  my $addr1 = shift;
+  my $addr2 = shift;
+  my $diff;
+
+  if ($address_length == 8) {
+    # Perl doesn't cope with wraparound arithmetic, so do it explicitly:
+    $diff = (hex($addr1)-hex($addr2)) % (0x10000000 * 16);
+    return sprintf("%08x", $diff);
+
+  } else {
+    # Do the addition in 7-nibble chunks to trivialize borrow handling.
+    # if ($main::opt_debug) { print STDERR "AddressSub $addr1 - $addr2 = "; }
+
+    my $a1 = hex(substr($addr1,-7));
+    $addr1 = substr($addr1,0,-7);
+    my $a2 = hex(substr($addr2,-7));
+    $addr2 = substr($addr2,0,-7);
+    my $b = 0;
+    if ($a2 > $a1) {
+      $b = 1;
+      $a1 += 0x10000000;
+    }
+    $diff = $a1 - $a2;
+    my $r = sprintf("%07x", $diff);
+
+    $a1 = hex(substr($addr1,-7));
+    $addr1 = substr($addr1,0,-7);
+    $a2 = hex(substr($addr2,-7)) + $b;
+    $addr2 = substr($addr2,0,-7);
+    $b = 0;
+    if ($a2 > $a1) {
+      $b = 1;
+      $a1 += 0x10000000;
+    }
+    $diff = $a1 - $a2;
+    $r = sprintf("%07x", $diff) . $r;
+
+    $a1 = hex($addr1);
+    $a2 = hex($addr2) + $b;
+    if ($a2 > $a1) { $a1 += 0x100; }
+    $diff = $a1 - $a2;
+    $r = sprintf("%02x", $diff) . $r;
+
+    # if ($main::opt_debug) { print STDERR "$r\n"; }
+
+    return $r;
+  }
+}
+
+# Increment a hex addresses of length $address_length.
+# Run pprof --test for unit test if this is changed.
+sub AddressInc {
+  my $addr = shift;
+  my $sum;
+
+  if ($address_length == 8) {
+    # Perl doesn't cope with wraparound arithmetic, so do it explicitly:
+    $sum = (hex($addr)+1) % (0x10000000 * 16);
+    return sprintf("%08x", $sum);
+
+  } else {
+    # Do the addition in 7-nibble chunks to trivialize carry handling.
+    # We are always doing this to step through the addresses in a function,
+    # and will almost never overflow the first chunk, so we check for this
+    # case and exit early.
+
+    # if ($main::opt_debug) { print STDERR "AddressInc $addr1 = "; }
+
+    my $a1 = substr($addr,-7);
+    $addr = substr($addr,0,-7);
+    $sum = hex($a1) + 1;
+    my $r = sprintf("%07x", $sum);
+    if ($sum <= 0xfffffff) {
+      $r = $addr . $r;
+      # if ($main::opt_debug) { print STDERR "$r\n"; }
+      return HexExtend($r);
+    } else {
+      $r = "0000000";
+    }
+
+    $a1 = substr($addr,-7);
+    $addr = substr($addr,0,-7);
+    $sum = hex($a1) + 1;
+    $r = sprintf("%07x", $sum) . $r;
+    if ($sum <= 0xfffffff) {
+      $r = $addr . $r;
+      # if ($main::opt_debug) { print STDERR "$r\n"; }
+      return HexExtend($r);
+    } else {
+      $r = "00000000000000";
+    }
+
+    $sum = hex($addr) + 1;
+    if ($sum > 0xff) { $sum -= 0x100; }
+    $r = sprintf("%02x", $sum) . $r;
+
+    # if ($main::opt_debug) { print STDERR "$r\n"; }
+    return $r;
+  }
+}
+
+# Extract symbols for all PC values found in profile
+sub ExtractSymbols {
+  my $libs = shift;
+  my $pcset = shift;
+
+  my $symbols = {};
+
+  # Map each PC value to the containing library.  To make this faster,
+  # we sort libraries by their starting pc value (highest first), and
+  # advance through the libraries as we advance the pc.  Sometimes the
+  # addresses of libraries may overlap with the addresses of the main
+  # binary, so to make sure the libraries 'win', we iterate over the
+  # libraries in reverse order (which assumes the binary doesn't start
+  # in the middle of a library, which seems a fair assumption).
+  my @pcs = (sort { $a cmp $b } keys(%{$pcset}));  # pcset is 0-extended strings
+  foreach my $lib (sort {$b->[1] cmp $a->[1]} @{$libs}) {
+    my $libname = $lib->[0];
+    my $start = $lib->[1];
+    my $finish = $lib->[2];
+    my $offset = $lib->[3];
+
+    # Get list of pcs that belong in this library.
+    my $contained = [];
+    my ($start_pc_index, $finish_pc_index);
+    # Find smallest finish_pc_index such that $finish < $pc[$finish_pc_index].
+    for ($finish_pc_index = $#pcs + 1; $finish_pc_index > 0;
+         $finish_pc_index--) {
+      last if $pcs[$finish_pc_index - 1] le $finish;
+    }
+    # Find smallest start_pc_index such that $start <= $pc[$start_pc_index].
+    for ($start_pc_index = $finish_pc_index; $start_pc_index > 0;
+         $start_pc_index--) {
+      last if $pcs[$start_pc_index - 1] lt $start;
+    }
+    # This keeps PC values higher than $pc[$finish_pc_index] in @pcs,
+    # in case there are overlaps in libraries and the main binary.
+    @{$contained} = splice(@pcs, $start_pc_index,
+                           $finish_pc_index - $start_pc_index);
+    # Map to symbols
+    MapToSymbols($libname, AddressSub($start, $offset), $contained, $symbols);
+  }
+
+  return $symbols;
+}
+
+# Map list of PC values to symbols for a given image
+sub MapToSymbols {
+  my $image = shift;
+  my $offset = shift;
+  my $pclist = shift;
+  my $symbols = shift;
+
+  my $debug = 0;
+
+  # Ignore empty binaries
+  if ($#{$pclist} < 0) { return; }
+
+  # Figure out the addr2line command to use
+  my $addr2line = $obj_tool_map{"addr2line"};
+  my $cmd = ShellEscape($addr2line, "-f", "-C", "-e", $image);
+  if (exists $obj_tool_map{"addr2line_pdb"}) {
+    $addr2line = $obj_tool_map{"addr2line_pdb"};
+    $cmd = ShellEscape($addr2line, "--demangle", "-f", "-C", "-e", $image);
+  }
+
+  # If "addr2line" isn't installed on the system at all, just use
+  # nm to get what info we can (function names, but not line numbers).
+  if (system(ShellEscape($addr2line, "--help") . " >$dev_null 2>&1") != 0) {
+    MapSymbolsWithNM($image, $offset, $pclist, $symbols);
+    return;
+  }
+
+  # "addr2line -i" can produce a variable number of lines per input
+  # address, with no separator that allows us to tell when data for
+  # the next address starts.  So we find the address for a special
+  # symbol (_fini) and interleave this address between all real
+  # addresses passed to addr2line.  The name of this special symbol
+  # can then be used as a separator.
+  $sep_address = undef;  # May be filled in by MapSymbolsWithNM()
+  my $nm_symbols = {};
+  MapSymbolsWithNM($image, $offset, $pclist, $nm_symbols);
+  if (defined($sep_address)) {
+    # Only add " -i" to addr2line if the binary supports it.
+    # addr2line --help returns 0, but not if it sees an unknown flag first.
+    if (system("$cmd -i --help >$dev_null 2>&1") == 0) {
+      $cmd .= " -i";
+    } else {
+      $sep_address = undef;   # no need for sep_address if we don't support -i
+    }
+  }
+
+  # Make file with all PC values with intervening 'sep_address' so
+  # that we can reliably detect the end of inlined function list
+  open(ADDRESSES, ">$main::tmpfile_sym") || error("$main::tmpfile_sym: $!\n");
+  if ($debug) { print("---- $image ---\n"); }
+  for (my $i = 0; $i <= $#{$pclist}; $i++) {
+    # addr2line always reads hex addresses, and does not need '0x' prefix.
+    if ($debug) { printf STDERR ("%s\n", $pclist->[$i]); }
+    printf ADDRESSES ("%s\n", AddressSub($pclist->[$i], $offset));
+    if (defined($sep_address)) {
+      printf ADDRESSES ("%s\n", $sep_address);
+    }
+  }
+  close(ADDRESSES);
+  if ($debug) {
+    print("----\n");
+    system("cat", $main::tmpfile_sym);
+    print("----\n");
+    system("$cmd < " . ShellEscape($main::tmpfile_sym));
+    print("----\n");
+  }
+
+  open(SYMBOLS, "$cmd <" . ShellEscape($main::tmpfile_sym) . " |")
+      || error("$cmd: $!\n");
+  my $count = 0;   # Index in pclist
+  while (<SYMBOLS>) {
+    # Read fullfunction and filelineinfo from next pair of lines
+    s/\r?\n$//g;
+    my $fullfunction = $_;
+    $_ = <SYMBOLS>;
+    s/\r?\n$//g;
+    my $filelinenum = $_;
+
+    if (defined($sep_address) && $fullfunction eq $sep_symbol) {
+      # Terminating marker for data for this address
+      $count++;
+      next;
+    }
+
+    $filelinenum =~ s|\\|/|g; # turn windows-style paths into unix-style paths
+
+    my $pcstr = $pclist->[$count];
+    my $function = ShortFunctionName($fullfunction);
+    my $nms = $nm_symbols->{$pcstr};
+    if (defined($nms)) {
+      if ($fullfunction eq '??') {
+        # nm found a symbol for us.
+        $function = $nms->[0];
+        $fullfunction = $nms->[2];
+      } else {
+	# MapSymbolsWithNM tags each routine with its starting address,
+	# useful in case the image has multiple occurrences of this
+	# routine.  (It uses a syntax that resembles template paramters,
+	# that are automatically stripped out by ShortFunctionName().)
+	# addr2line does not provide the same information.  So we check
+	# if nm disambiguated our symbol, and if so take the annotated
+	# (nm) version of the routine-name.  TODO(csilvers): this won't
+	# catch overloaded, inlined symbols, which nm doesn't see.
+	# Better would be to do a check similar to nm's, in this fn.
+	if ($nms->[2] =~ m/^\Q$function\E/) {  # sanity check it's the right fn
+	  $function = $nms->[0];
+	  $fullfunction = $nms->[2];
+	}
+      }
+    }
+    
+    # Prepend to accumulated symbols for pcstr
+    # (so that caller comes before callee)
+    my $sym = $symbols->{$pcstr};
+    if (!defined($sym)) {
+      $sym = [];
+      $symbols->{$pcstr} = $sym;
+    }
+    unshift(@{$sym}, $function, $filelinenum, $fullfunction);
+    if ($debug) { printf STDERR ("%s => [%s]\n", $pcstr, join(" ", @{$sym})); }
+    if (!defined($sep_address)) {
+      # Inlining is off, so this entry ends immediately
+      $count++;
+    }
+  }
+  close(SYMBOLS);
+}
+
+# Use nm to map the list of referenced PCs to symbols.  Return true iff we
+# are able to read procedure information via nm.
+sub MapSymbolsWithNM {
+  my $image = shift;
+  my $offset = shift;
+  my $pclist = shift;
+  my $symbols = shift;
+
+  # Get nm output sorted by increasing address
+  my $symbol_table = GetProcedureBoundaries($image, ".");
+  if (!%{$symbol_table}) {
+    return 0;
+  }
+  # Start addresses are already the right length (8 or 16 hex digits).
+  my @names = sort { $symbol_table->{$a}->[0] cmp $symbol_table->{$b}->[0] }
+    keys(%{$symbol_table});
+
+  if ($#names < 0) {
+    # No symbols: just use addresses
+    foreach my $pc (@{$pclist}) {
+      my $pcstr = "0x" . $pc;
+      $symbols->{$pc} = [$pcstr, "?", $pcstr];
+    }
+    return 0;
+  }
+
+  # Sort addresses so we can do a join against nm output
+  my $index = 0;
+  my $fullname = $names[0];
+  my $name = ShortFunctionName($fullname);
+  foreach my $pc (sort { $a cmp $b } @{$pclist}) {
+    # Adjust for mapped offset
+    my $mpc = AddressSub($pc, $offset);
+    while (($index < $#names) && ($mpc ge $symbol_table->{$fullname}->[1])){
+      $index++;
+      $fullname = $names[$index];
+      $name = ShortFunctionName($fullname);
+    }
+    if ($mpc lt $symbol_table->{$fullname}->[1]) {
+      $symbols->{$pc} = [$name, "?", $fullname];
+    } else {
+      my $pcstr = "0x" . $pc;
+      $symbols->{$pc} = [$pcstr, "?", $pcstr];
+    }
+  }
+  return 1;
+}
+
+sub ShortFunctionName {
+  my $function = shift;
+  while ($function =~ s/\([^()]*\)(\s*const)?//g) { }   # Argument types
+  while ($function =~ s/<[^<>]*>//g)  { }    # Remove template arguments
+  $function =~ s/^.*\s+(\w+::)/$1/;          # Remove leading type
+  return $function;
+}
+
+# Trim overly long symbols found in disassembler output
+sub CleanDisassembly {
+  my $d = shift;
+  while ($d =~ s/\([^()%]*\)(\s*const)?//g) { } # Argument types, not (%rax)
+  while ($d =~ s/(\w+)<[^<>]*>/$1/g)  { }       # Remove template arguments
+  return $d;
+}
+
+# Clean file name for display
+sub CleanFileName {
+  my ($f) = @_;
+  $f =~ s|^/proc/self/cwd/||;
+  $f =~ s|^\./||;
+  return $f;
+}
+
+# Make address relative to section and clean up for display
+sub UnparseAddress {
+  my ($offset, $address) = @_;
+  $address = AddressSub($address, $offset);
+  $address =~ s/^0x//;
+  $address =~ s/^0*//;
+  return $address;
+}
+
+##### Miscellaneous #####
+
+# Find the right versions of the above object tools to use.  The
+# argument is the program file being analyzed, and should be an ELF
+# 32-bit or ELF 64-bit executable file.  The location of the tools
+# is determined by considering the following options in this order:
+#   1) --tools option, if set
+#   2) PPROF_TOOLS environment variable, if set
+#   3) the environment
+sub ConfigureObjTools {
+  my $prog_file = shift;
+
+  # Check for the existence of $prog_file because /usr/bin/file does not
+  # predictably return error status in prod.
+  (-e $prog_file)  || error("$prog_file does not exist.\n");
+
+  my $file_type = undef;
+  if (-e "/usr/bin/file") {
+    # Follow symlinks (at least for systems where "file" supports that).
+    my $escaped_prog_file = ShellEscape($prog_file);
+    $file_type = `/usr/bin/file -L $escaped_prog_file 2>$dev_null ||
+                  /usr/bin/file $escaped_prog_file`;
+  } elsif ($^O == "MSWin32") {
+    $file_type = "MS Windows";
+  } else {
+    print STDERR "WARNING: Can't determine the file type of $prog_file";
+  }
+
+  if ($file_type =~ /64-bit/) {
+    # Change $address_length to 16 if the program file is ELF 64-bit.
+    # We can't detect this from many (most?) heap or lock contention
+    # profiles, since the actual addresses referenced are generally in low
+    # memory even for 64-bit programs.
+    $address_length = 16;
+  }
+
+  if ($file_type =~ /MS Windows/) {
+    # For windows, we provide a version of nm and addr2line as part of
+    # the opensource release, which is capable of parsing
+    # Windows-style PDB executables.  It should live in the path, or
+    # in the same directory as pprof.
+    $obj_tool_map{"nm_pdb"} = "nm-pdb";
+    $obj_tool_map{"addr2line_pdb"} = "addr2line-pdb";
+  }
+
+  if ($file_type =~ /Mach-O/) {
+    # OS X uses otool to examine Mach-O files, rather than objdump.
+    $obj_tool_map{"otool"} = "otool";
+    $obj_tool_map{"addr2line"} = "false";  # no addr2line
+    $obj_tool_map{"objdump"} = "false";  # no objdump
+  }
+
+  # Go fill in %obj_tool_map with the pathnames to use:
+  foreach my $tool (keys %obj_tool_map) {
+    $obj_tool_map{$tool} = ConfigureTool($obj_tool_map{$tool});
+  }
+}
+
+# Returns the path of a caller-specified object tool.  If --tools or
+# PPROF_TOOLS are specified, then returns the full path to the tool
+# with that prefix.  Otherwise, returns the path unmodified (which
+# means we will look for it on PATH).
+sub ConfigureTool {
+  my $tool = shift;
+  my $path;
+
+  # --tools (or $PPROF_TOOLS) is a comma separated list, where each
+  # item is either a) a pathname prefix, or b) a map of the form
+  # <tool>:<path>.  First we look for an entry of type (b) for our
+  # tool.  If one is found, we use it.  Otherwise, we consider all the
+  # pathname prefixes in turn, until one yields an existing file.  If
+  # none does, we use a default path.
+  my $tools = $main::opt_tools || $ENV{"PPROF_TOOLS"} || "";
+  if ($tools =~ m/(,|^)\Q$tool\E:([^,]*)/) {
+    $path = $2;
+    # TODO(csilvers): sanity-check that $path exists?  Hard if it's relative.
+  } elsif ($tools ne '') {
+    foreach my $prefix (split(',', $tools)) {
+      next if ($prefix =~ /:/);    # ignore "tool:fullpath" entries in the list
+      if (-x $prefix . $tool) {
+        $path = $prefix . $tool;
+        last;
+      }
+    }
+    if (!$path) {
+      error("No '$tool' found with prefix specified by " .
+            "--tools (or \$PPROF_TOOLS) '$tools'\n");
+    }
+  } else {
+    # ... otherwise use the version that exists in the same directory as
+    # pprof.  If there's nothing there, use $PATH.
+    $0 =~ m,[^/]*$,;     # this is everything after the last slash
+    my $dirname = $`;    # this is everything up to and including the last slash
+    if (-x "$dirname$tool") {
+      $path = "$dirname$tool";
+    } else { 
+      $path = $tool;
+    }
+  }
+  if ($main::opt_debug) { print STDERR "Using '$path' for '$tool'.\n"; }
+  return $path;
+}
+
+sub ShellEscape {
+  my @escaped_words = ();
+  foreach my $word (@_) {
+    my $escaped_word = $word;
+    if ($word =~ m![^a-zA-Z0-9/.,_=-]!) {  # check for anything not in whitelist
+      $escaped_word =~ s/'/'\\''/;
+      $escaped_word = "'$escaped_word'";
+    }
+    push(@escaped_words, $escaped_word);
+  }
+  return join(" ", @escaped_words);
+}
+
+sub cleanup {
+  unlink($main::tmpfile_sym);
+  unlink(keys %main::tempnames);
+
+  # We leave any collected profiles in $HOME/pprof in case the user wants
+  # to look at them later.  We print a message informing them of this.
+  if ((scalar(@main::profile_files) > 0) &&
+      defined($main::collected_profile)) {
+    if (scalar(@main::profile_files) == 1) {
+      print STDERR "Dynamically gathered profile is in $main::collected_profile\n";
+    }
+    print STDERR "If you want to investigate this profile further, you can do:\n";
+    print STDERR "\n";
+    print STDERR "  pprof \\\n";
+    print STDERR "    $main::prog \\\n";
+    print STDERR "    $main::collected_profile\n";
+    print STDERR "\n";
+  }
+}
+
+sub sighandler {
+  cleanup();
+  exit(1);
+}
+
+sub error {
+  my $msg = shift;
+  print STDERR $msg;
+  cleanup();
+  exit(1);
+}
+
+
+# Run $nm_command and get all the resulting procedure boundaries whose
+# names match "$regexp" and returns them in a hashtable mapping from
+# procedure name to a two-element vector of [start address, end address]
+sub GetProcedureBoundariesViaNm {
+  my $escaped_nm_command = shift;    # shell-escaped
+  my $regexp = shift;
+
+  my $symbol_table = {};
+  open(NM, "$escaped_nm_command |") || error("$escaped_nm_command: $!\n");
+  my $last_start = "0";
+  my $routine = "";
+  while (<NM>) {
+    s/\r//g;         # turn windows-looking lines into unix-looking lines
+    if (m/^\s*([0-9a-f]+) (.) (..*)/) {
+      my $start_val = $1;
+      my $type = $2;
+      my $this_routine = $3;
+
+      # It's possible for two symbols to share the same address, if
+      # one is a zero-length variable (like __start_google_malloc) or
+      # one symbol is a weak alias to another (like __libc_malloc).
+      # In such cases, we want to ignore all values except for the
+      # actual symbol, which in nm-speak has type "T".  The logic
+      # below does this, though it's a bit tricky: what happens when
+      # we have a series of lines with the same address, is the first
+      # one gets queued up to be processed.  However, it won't
+      # *actually* be processed until later, when we read a line with
+      # a different address.  That means that as long as we're reading
+      # lines with the same address, we have a chance to replace that
+      # item in the queue, which we do whenever we see a 'T' entry --
+      # that is, a line with type 'T'.  If we never see a 'T' entry,
+      # we'll just go ahead and process the first entry (which never
+      # got touched in the queue), and ignore the others.
+      if ($start_val eq $last_start && $type =~ /t/i) {
+        # We are the 'T' symbol at this address, replace previous symbol.
+        $routine = $this_routine;
+        next;
+      } elsif ($start_val eq $last_start) {
+        # We're not the 'T' symbol at this address, so ignore us.
+        next;
+      }
+
+      if ($this_routine eq $sep_symbol) {
+        $sep_address = HexExtend($start_val);
+      }
+
+      # Tag this routine with the starting address in case the image
+      # has multiple occurrences of this routine.  We use a syntax
+      # that resembles template paramters that are automatically
+      # stripped out by ShortFunctionName()
+      $this_routine .= "<$start_val>";
+
+      if (defined($routine) && $routine =~ m/$regexp/) {
+        $symbol_table->{$routine} = [HexExtend($last_start),
+                                     HexExtend($start_val)];
+      }
+      $last_start = $start_val;
+      $routine = $this_routine;
+    } elsif (m/^Loaded image name: (.+)/) {
+      # The win32 nm workalike emits information about the binary it is using.
+      if ($main::opt_debug) { print STDERR "Using Image $1\n"; }
+    } elsif (m/^PDB file name: (.+)/) {
+      # The win32 nm workalike emits information about the pdb it is using.
+      if ($main::opt_debug) { print STDERR "Using PDB $1\n"; }
+    }
+  }
+  close(NM);
+  # Handle the last line in the nm output.  Unfortunately, we don't know
+  # how big this last symbol is, because we don't know how big the file
+  # is.  For now, we just give it a size of 0.
+  # TODO(csilvers): do better here.
+  if (defined($routine) && $routine =~ m/$regexp/) {
+    $symbol_table->{$routine} = [HexExtend($last_start),
+                                 HexExtend($last_start)];
+  }
+  return $symbol_table;
+}
+
+# Gets the procedure boundaries for all routines in "$image" whose names
+# match "$regexp" and returns them in a hashtable mapping from procedure
+# name to a two-element vector of [start address, end address].
+# Will return an empty map if nm is not installed or not working properly.
+sub GetProcedureBoundaries {
+  my $image = shift;
+  my $regexp = shift;
+
+  # If $image doesn't start with /, then put ./ in front of it.  This works
+  # around an obnoxious bug in our probing of nm -f behavior.
+  # "nm -f $image" is supposed to fail on GNU nm, but if:
+  #
+  # a. $image starts with [BbSsPp] (for example, bin/foo/bar), AND
+  # b. you have a.out in your current directory (a not uncommon occurence)
+  #
+  # then "nm -f $image" succeeds because -f only looks at the first letter of
+  # the argument, which looks valid because it's [BbSsPp], and then since
+  # there's no image provided, it looks for a.out and finds it.
+  #
+  # This regex makes sure that $image starts with . or /, forcing the -f
+  # parsing to fail since . and / are not valid formats.
+  $image =~ s#^[^/]#./$&#;
+
+  # For libc libraries, the copy in /usr/lib/debug contains debugging symbols
+  my $debugging = DebuggingLibrary($image);
+  if ($debugging) {
+    $image = $debugging;
+  }
+
+  my $nm = $obj_tool_map{"nm"};
+  my $cppfilt = $obj_tool_map{"c++filt"};
+
+  # nm can fail for two reasons: 1) $image isn't a debug library; 2) nm
+  # binary doesn't support --demangle.  In addition, for OS X we need
+  # to use the -f flag to get 'flat' nm output (otherwise we don't sort
+  # properly and get incorrect results).  Unfortunately, GNU nm uses -f
+  # in an incompatible way.  So first we test whether our nm supports
+  # --demangle and -f.
+  my $demangle_flag = "";
+  my $cppfilt_flag = "";
+  my $to_devnull = ">$dev_null 2>&1";
+  if (system(ShellEscape($nm, "--demangle", "image") . $to_devnull) == 0) {
+    # In this mode, we do "nm --demangle <foo>"
+    $demangle_flag = "--demangle";
+    $cppfilt_flag = "";
+  } elsif (system(ShellEscape($cppfilt, $image) . $to_devnull) == 0) {
+    # In this mode, we do "nm <foo> | c++filt"
+    $cppfilt_flag = " | " . ShellEscape($cppfilt);
+  };
+  my $flatten_flag = "";
+  if (system(ShellEscape($nm, "-f", $image) . $to_devnull) == 0) {
+    $flatten_flag = "-f";
+  }
+
+  # Finally, in the case $imagie isn't a debug library, we try again with
+  # -D to at least get *exported* symbols.  If we can't use --demangle,
+  # we use c++filt instead, if it exists on this system.
+  my @nm_commands = (ShellEscape($nm, "-n", $flatten_flag, $demangle_flag,
+                                 $image) . " 2>$dev_null $cppfilt_flag",
+                     ShellEscape($nm, "-D", "-n", $flatten_flag, $demangle_flag,
+                                 $image) . " 2>$dev_null $cppfilt_flag",
+                     # 6nm is for Go binaries
+                     ShellEscape("6nm", "$image") . " 2>$dev_null | sort",
+                     );
+
+  # If the executable is an MS Windows PDB-format executable, we'll
+  # have set up obj_tool_map("nm_pdb").  In this case, we actually
+  # want to use both unix nm and windows-specific nm_pdb, since
+  # PDB-format executables can apparently include dwarf .o files.
+  if (exists $obj_tool_map{"nm_pdb"}) {
+    push(@nm_commands,
+         ShellEscape($obj_tool_map{"nm_pdb"}, "--demangle", $image)
+         . " 2>$dev_null");
+  }
+
+  foreach my $nm_command (@nm_commands) {
+    my $symbol_table = GetProcedureBoundariesViaNm($nm_command, $regexp);
+    return $symbol_table if (%{$symbol_table});
+  }
+  my $symbol_table = {};
+  return $symbol_table;
+}
+
+
+# The test vectors for AddressAdd/Sub/Inc are 8-16-nibble hex strings.
+# To make them more readable, we add underscores at interesting places.
+# This routine removes the underscores, producing the canonical representation
+# used by pprof to represent addresses, particularly in the tested routines.
+sub CanonicalHex {
+  my $arg = shift;
+  return join '', (split '_',$arg);
+}
+
+
+# Unit test for AddressAdd:
+sub AddressAddUnitTest {
+  my $test_data_8 = shift;
+  my $test_data_16 = shift;
+  my $error_count = 0;
+  my $fail_count = 0;
+  my $pass_count = 0;
+  # print STDERR "AddressAddUnitTest: ", 1+$#{$test_data_8}, " tests\n";
+
+  # First a few 8-nibble addresses.  Note that this implementation uses
+  # plain old arithmetic, so a quick sanity check along with verifying what
+  # happens to overflow (we want it to wrap):
+  $address_length = 8;
+  foreach my $row (@{$test_data_8}) {
+    if ($main::opt_debug and $main::opt_test) { print STDERR "@{$row}\n"; }
+    my $sum = AddressAdd ($row->[0], $row->[1]);
+    if ($sum ne $row->[2]) {
+      printf STDERR "ERROR: %s != %s + %s = %s\n", $sum,
+             $row->[0], $row->[1], $row->[2];
+      ++$fail_count;
+    } else {
+      ++$pass_count;
+    }
+  }
+  printf STDERR "AddressAdd 32-bit tests: %d passes, %d failures\n",
+         $pass_count, $fail_count;
+  $error_count = $fail_count;
+  $fail_count = 0;
+  $pass_count = 0;
+
+  # Now 16-nibble addresses.
+  $address_length = 16;
+  foreach my $row (@{$test_data_16}) {
+    if ($main::opt_debug and $main::opt_test) { print STDERR "@{$row}\n"; }
+    my $sum = AddressAdd (CanonicalHex($row->[0]), CanonicalHex($row->[1]));
+    my $expected = join '', (split '_',$row->[2]);
+    if ($sum ne CanonicalHex($row->[2])) {
+      printf STDERR "ERROR: %s != %s + %s = %s\n", $sum,
+             $row->[0], $row->[1], $row->[2];
+      ++$fail_count;
+    } else {
+      ++$pass_count;
+    }
+  }
+  printf STDERR "AddressAdd 64-bit tests: %d passes, %d failures\n",
+         $pass_count, $fail_count;
+  $error_count += $fail_count;
+
+  return $error_count;
+}
+
+
+# Unit test for AddressSub:
+sub AddressSubUnitTest {
+  my $test_data_8 = shift;
+  my $test_data_16 = shift;
+  my $error_count = 0;
+  my $fail_count = 0;
+  my $pass_count = 0;
+  # print STDERR "AddressSubUnitTest: ", 1+$#{$test_data_8}, " tests\n";
+
+  # First a few 8-nibble addresses.  Note that this implementation uses
+  # plain old arithmetic, so a quick sanity check along with verifying what
+  # happens to overflow (we want it to wrap):
+  $address_length = 8;
+  foreach my $row (@{$test_data_8}) {
+    if ($main::opt_debug and $main::opt_test) { print STDERR "@{$row}\n"; }
+    my $sum = AddressSub ($row->[0], $row->[1]);
+    if ($sum ne $row->[3]) {
+      printf STDERR "ERROR: %s != %s - %s = %s\n", $sum,
+             $row->[0], $row->[1], $row->[3];
+      ++$fail_count;
+    } else {
+      ++$pass_count;
+    }
+  }
+  printf STDERR "AddressSub 32-bit tests: %d passes, %d failures\n",
+         $pass_count, $fail_count;
+  $error_count = $fail_count;
+  $fail_count = 0;
+  $pass_count = 0;
+
+  # Now 16-nibble addresses.
+  $address_length = 16;
+  foreach my $row (@{$test_data_16}) {
+    if ($main::opt_debug and $main::opt_test) { print STDERR "@{$row}\n"; }
+    my $sum = AddressSub (CanonicalHex($row->[0]), CanonicalHex($row->[1]));
+    if ($sum ne CanonicalHex($row->[3])) {
+      printf STDERR "ERROR: %s != %s - %s = %s\n", $sum,
+             $row->[0], $row->[1], $row->[3];
+      ++$fail_count;
+    } else {
+      ++$pass_count;
+    }
+  }
+  printf STDERR "AddressSub 64-bit tests: %d passes, %d failures\n",
+         $pass_count, $fail_count;
+  $error_count += $fail_count;
+
+  return $error_count;
+}
+
+
+# Unit test for AddressInc:
+sub AddressIncUnitTest {
+  my $test_data_8 = shift;
+  my $test_data_16 = shift;
+  my $error_count = 0;
+  my $fail_count = 0;
+  my $pass_count = 0;
+  # print STDERR "AddressIncUnitTest: ", 1+$#{$test_data_8}, " tests\n";
+
+  # First a few 8-nibble addresses.  Note that this implementation uses
+  # plain old arithmetic, so a quick sanity check along with verifying what
+  # happens to overflow (we want it to wrap):
+  $address_length = 8;
+  foreach my $row (@{$test_data_8}) {
+    if ($main::opt_debug and $main::opt_test) { print STDERR "@{$row}\n"; }
+    my $sum = AddressInc ($row->[0]);
+    if ($sum ne $row->[4]) {
+      printf STDERR "ERROR: %s != %s + 1 = %s\n", $sum,
+             $row->[0], $row->[4];
+      ++$fail_count;
+    } else {
+      ++$pass_count;
+    }
+  }
+  printf STDERR "AddressInc 32-bit tests: %d passes, %d failures\n",
+         $pass_count, $fail_count;
+  $error_count = $fail_count;
+  $fail_count = 0;
+  $pass_count = 0;
+
+  # Now 16-nibble addresses.
+  $address_length = 16;
+  foreach my $row (@{$test_data_16}) {
+    if ($main::opt_debug and $main::opt_test) { print STDERR "@{$row}\n"; }
+    my $sum = AddressInc (CanonicalHex($row->[0]));
+    if ($sum ne CanonicalHex($row->[4])) {
+      printf STDERR "ERROR: %s != %s + 1 = %s\n", $sum,
+             $row->[0], $row->[4];
+      ++$fail_count;
+    } else {
+      ++$pass_count;
+    }
+  }
+  printf STDERR "AddressInc 64-bit tests: %d passes, %d failures\n",
+         $pass_count, $fail_count;
+  $error_count += $fail_count;
+
+  return $error_count;
+}
+
+
+# Driver for unit tests.
+# Currently just the address add/subtract/increment routines for 64-bit.
+sub RunUnitTests {
+  my $error_count = 0;
+
+  # This is a list of tuples [a, b, a+b, a-b, a+1]
+  my $unit_test_data_8 = [
+    [qw(aaaaaaaa 50505050 fafafafa 5a5a5a5a aaaaaaab)],
+    [qw(50505050 aaaaaaaa fafafafa a5a5a5a6 50505051)],
+    [qw(ffffffff aaaaaaaa aaaaaaa9 55555555 00000000)],
+    [qw(00000001 ffffffff 00000000 00000002 00000002)],
+    [qw(00000001 fffffff0 fffffff1 00000011 00000002)],
+  ];
+  my $unit_test_data_16 = [
+    # The implementation handles data in 7-nibble chunks, so those are the
+    # interesting boundaries.
+    [qw(aaaaaaaa 50505050
+        00_000000f_afafafa 00_0000005_a5a5a5a 00_000000a_aaaaaab)],
+    [qw(50505050 aaaaaaaa
+        00_000000f_afafafa ff_ffffffa_5a5a5a6 00_0000005_0505051)],
+    [qw(ffffffff aaaaaaaa
+        00_000001a_aaaaaa9 00_0000005_5555555 00_0000010_0000000)],
+    [qw(00000001 ffffffff
+        00_0000010_0000000 ff_ffffff0_0000002 00_0000000_0000002)],
+    [qw(00000001 fffffff0
+        00_000000f_ffffff1 ff_ffffff0_0000011 00_0000000_0000002)],
+
+    [qw(00_a00000a_aaaaaaa 50505050
+        00_a00000f_afafafa 00_a000005_a5a5a5a 00_a00000a_aaaaaab)],
+    [qw(0f_fff0005_0505050 aaaaaaaa
+        0f_fff000f_afafafa 0f_ffefffa_5a5a5a6 0f_fff0005_0505051)],
+    [qw(00_000000f_fffffff 01_800000a_aaaaaaa
+        01_800001a_aaaaaa9 fe_8000005_5555555 00_0000010_0000000)],
+    [qw(00_0000000_0000001 ff_fffffff_fffffff
+        00_0000000_0000000 00_0000000_0000002 00_0000000_0000002)],
+    [qw(00_0000000_0000001 ff_fffffff_ffffff0
+        ff_fffffff_ffffff1 00_0000000_0000011 00_0000000_0000002)],
+  ];
+
+  $error_count += AddressAddUnitTest($unit_test_data_8, $unit_test_data_16);
+  $error_count += AddressSubUnitTest($unit_test_data_8, $unit_test_data_16);
+  $error_count += AddressIncUnitTest($unit_test_data_8, $unit_test_data_16);
+  if ($error_count > 0) {
+    print STDERR $error_count, " errors: FAILED\n";
+  } else {
+    print STDERR "PASS\n";
+  }
+  exit ($error_count);
+}