Bug 1269171 - Change how mozalloc.h is hooked in STL wrappers. r=froydnj
authorMike Hommey <mh+mozilla@glandium.org>
Wed, 18 May 2016 16:37:19 +0900
changeset 298410 68da139d0866977c0ada86319fa94388f2255446
parent 298409 a640e6fa8ab9977fb6c5bcf63dc4daca6699477b
child 298411 360c31dc69af6c261f2d8fc8dfa82203f9247409
push id30281
push usercbook@mozilla.com
push dateTue, 24 May 2016 12:54:02 +0000
treeherdermozilla-central@829d3be6ba64 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersfroydnj
bugs1269171
milestone49.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1269171 - Change how mozalloc.h is hooked in STL wrappers. r=froydnj Since the introduction of the STL wrappers, they have included mozalloc.h, and multiple times, we've hit header reentrancy problems, and worked around them as best as we could. Taking a step back, all mozalloc.h does is: - declare moz_* allocator functions. - define inline implementations of various operator new/delete variants. The first only requires the functions to be declared before they are used, so mozalloc.h only needs to be included before anything that would use those functions. The second doesn't actually require a specific order, as long as the declaration for those functions comes before their use, and they are either declared in <new> or implicitly by the C++ compiler. So all in all, it doesn't matter that mozalloc.h is included before the wrapped STL headers. What matters is that it's included when STL headers are included. So arrange things such that mozalloc.h is included after the first wrapped STL header is fully preprocessed (and all its includes have been included).
config/gcc-stl-wrapper.template.h
config/make-stl-wrappers.py
config/msvc-stl-wrapper.template.h
memory/mozalloc/mozalloc.h
--- a/config/gcc-stl-wrapper.template.h
+++ b/config/gcc-stl-wrapper.template.h
@@ -12,56 +12,54 @@
 // compiling ObjC.
 #if defined(__EXCEPTIONS) && __EXCEPTIONS && !(__OBJC__ && __GNUC__ && XP_IOS)
 #  error "STL code can only be used with -fno-exceptions"
 #endif
 
 // Silence "warning: #include_next is a GCC extension"
 #pragma GCC system_header
 
-// Don't include mozalloc for cstdlib. See bug 1245076.
-#ifndef moz_dont_include_mozalloc_for_cstdlib
-#  define moz_dont_include_mozalloc_for_cstdlib
-#endif
-#ifndef moz_dont_include_mozalloc_for_${HEADER}
-// mozalloc.h wants <new>; break the cycle by always explicitly
-// including <new> here.  NB: this is a tad sneaky.  Sez the gcc docs:
-//
-//    `#include_next' does not distinguish between <file> and "file"
-//    inclusion, nor does it check that the file you specify has the
-//    same name as the current file. It simply looks for the file
-//    named, starting with the directory in the search path after the
-//    one where the current file was found.
-#  include_next <new>
-
-// See if we're in code that can use mozalloc.  NB: this duplicates
-// code in nscore.h because nscore.h pulls in prtypes.h, and chromium
-// can't build with that being included before base/basictypes.h.
-#  if !defined(XPCOM_GLUE) && !defined(NS_NO_XPCOM) && !defined(MOZ_NO_MOZALLOC)
-#    include "mozilla/mozalloc.h"
-#  else
-#    error "STL code can only be used with infallible ::operator new()"
-#  endif
-
-#endif
-
 #if defined(DEBUG) && !defined(_GLIBCXX_DEBUG)
 // Enable checked iterators and other goodies
 //
 // FIXME/bug 551254: gcc's debug STL implementation requires -frtti.
 // Figure out how to resolve this with -fno-rtti.  Maybe build with
 // -frtti in DEBUG builds?
 //
 //  # define _GLIBCXX_DEBUG 1
 #endif
 
+// Don't include mozalloc for cstdlib. See bug 1245076.
+#ifndef moz_dont_include_mozalloc_for_cstdlib
+#  define moz_dont_include_mozalloc_for_cstdlib
+#endif
+
+// Include mozalloc after the STL header and all other headers it includes
+// have been preprocessed.
+#if !defined(MOZ_INCLUDE_MOZALLOC_H) && \
+    !defined(moz_dont_include_mozalloc_for_${HEADER})
+#  define MOZ_INCLUDE_MOZALLOC_H
+#  define MOZ_INCLUDE_MOZALLOC_H_FROM_${HEADER}
+#endif
+
 #pragma GCC visibility push(default)
 #include_next <${HEADER}>
 #pragma GCC visibility pop
 
+#ifdef MOZ_INCLUDE_MOZALLOC_H_FROM_${HEADER}
+// See if we're in code that can use mozalloc.  NB: this duplicates
+// code in nscore.h because nscore.h pulls in prtypes.h, and chromium
+// can't build with that being included before base/basictypes.h.
+#  if !defined(XPCOM_GLUE) && !defined(NS_NO_XPCOM) && !defined(MOZ_NO_MOZALLOC)
+#    include "mozilla/mozalloc.h"
+#  else
+#    error "STL code can only be used with infallible ::operator new()"
+#  endif
+#endif
+
 // gcc calls a __throw_*() function from bits/functexcept.h when it
 // wants to "throw an exception".  functexcept exists nominally to
 // support -fno-exceptions, but since we'll always use the system
 // libstdc++, and it's compiled with exceptions, then in practice
 // these __throw_*() functions will always throw exceptions (shades of
 // -fshort-wchar).  We don't want that and so define our own inlined
 // __throw_*().
 #ifndef mozilla_throw_gcc_h
--- a/config/make-stl-wrappers.py
+++ b/config/make-stl-wrappers.py
@@ -25,28 +25,26 @@ def header_path(header, compiler):
 def is_comment(line):
     return re.match(r'\s*#.*', line)
 
 def main(outdir, compiler, template_file, header_list_file):
     if not os.path.isdir(outdir):
         os.mkdir(outdir)
 
     template = open(template_file, 'r').read()
-    path_to_new = header_path('new', compiler)
 
     for header in open(header_list_file, 'r'):
         header = header.rstrip()
         if 0 == len(header) or is_comment(header):
             continue
 
         path = header_path(header, compiler)
         with FileAvoidWrite(os.path.join(outdir, header)) as f:
             f.write(string.Template(template).substitute(HEADER=header,
-                                                         HEADER_PATH=path,
-                                                         NEW_HEADER_PATH=path_to_new))
+                                                         HEADER_PATH=path))
 
 
 if __name__ == '__main__':
     if 5 != len(sys.argv):
         print("""Usage:
   python {0} OUT_DIR ('msvc'|'gcc') TEMPLATE_FILE HEADER_LIST_FILE
 """.format(sys.argv[0]), file=sys.stderr)
         sys.exit(1)
--- a/config/msvc-stl-wrapper.template.h
+++ b/config/msvc-stl-wrapper.template.h
@@ -3,45 +3,33 @@
  */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef mozilla_${HEADER}_h
 #define mozilla_${HEADER}_h
 
-#ifndef MOZ_HAVE_INCLUDED_ALLOC
-#define MOZ_HAVE_INCLUDED_ALLOC
-
 #if _HAS_EXCEPTIONS
 #  error "STL code can only be used with -fno-exceptions"
 #endif
 
+// Include mozalloc after the STL header and all other headers it includes
+// have been preprocessed.
+#if !defined(MOZ_INCLUDE_MOZALLOC_H)
+#  define MOZ_INCLUDE_MOZALLOC_H
+#  define MOZ_INCLUDE_MOZALLOC_H_FROM_${HEADER}
+#endif
+
 // Code built with !_HAS_EXCEPTIONS calls std::_Throw(), but the win2k
 // CRT doesn't export std::_Throw().  So we define it.
 #ifndef mozilla_Throw_h
 #  include "mozilla/throw_msvc.h"
 #endif
 
-// Code might include <new> before other wrapped headers, but <new>
-// includes <exception> and so we want to wrap it.  But mozalloc.h
-// wants <new> also, so we break the cycle by always explicitly
-// including <new> here.
-#include <${NEW_HEADER_PATH}>
-
-// See if we're in code that can use mozalloc.  NB: this duplicates
-// code in nscore.h because nscore.h pulls in prtypes.h, and chromium
-// can't build with that being included before base/basictypes.h.
-#if !defined(XPCOM_GLUE) && !defined(NS_NO_XPCOM) && !defined(MOZ_NO_MOZALLOC)
-#  include "mozilla/mozalloc.h"
-#else
-#  error "STL code can only be used with infallible ::operator new()"
-#endif
-#endif /* MOZ_HAVE_INCLUDED_ALLOC */
-
 #ifdef _DEBUG
 // From
 //   http://msdn.microsoft.com/en-us/library/aa985982%28VS.80%29.aspx
 // and
 //   http://msdn.microsoft.com/en-us/library/aa985965%28VS.80%29.aspx
 // there appear to be two types of STL container checking.  The
 // former is enabled by -D_DEBUG (which is implied by -MDd or -MTd), and
 // looks to be full generation/mutation checked iterators as done by
@@ -70,9 +58,20 @@
 //        but that's OK because we're not throwing them.
 #pragma warning( push )
 #pragma warning( disable : 4275 4530 )
 
 #include <${HEADER_PATH}>
 
 #pragma warning( pop )
 
+#ifdef MOZ_INCLUDE_MOZALLOC_H_FROM_${HEADER}
+// See if we're in code that can use mozalloc.  NB: this duplicates
+// code in nscore.h because nscore.h pulls in prtypes.h, and chromium
+// can't build with that being included before base/basictypes.h.
+#  if !defined(XPCOM_GLUE) && !defined(NS_NO_XPCOM) && !defined(MOZ_NO_MOZALLOC)
+#    include "mozilla/mozalloc.h"
+#  else
+#    error "STL code can only be used with infallible ::operator new()"
+#  endif
+#endif
+
 #endif  // if mozilla_${HEADER}_h
--- a/memory/mozalloc/mozalloc.h
+++ b/memory/mozalloc/mozalloc.h
@@ -7,20 +7,27 @@
 
 #ifndef mozilla_mozalloc_h
 #define mozilla_mozalloc_h
 
 /*
  * https://bugzilla.mozilla.org/show_bug.cgi?id=427099
  */
 
-#include <stdlib.h>
-#include <string.h>
 #if defined(__cplusplus)
 #  include <new>
+// Since libstdc++ 6, including the C headers (e.g. stdlib.h) instead of the
+// corresponding C++ header (e.g. cstdlib) can cause confusion in C++ code
+// using things defined there. Specifically, with stdlib.h, the use of abs()
+// in gfx/graphite2/src/inc/UtfCodec.h somehow ends up picking the wrong abs()
+#  include <cstdlib>
+#  include <cstring>
+#else
+#  include <stdlib.h>
+#  include <string.h>
 #endif
 
 #if defined(__cplusplus)
 #include "mozilla/fallible.h"
 #include "mozilla/TemplateLib.h"
 #endif
 #include "mozilla/Attributes.h"
 #include "mozilla/Types.h"