new file mode 100644
--- /dev/null
+++ b/build/link.py
@@ -0,0 +1,79 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is cl.py: a python wrapper for cl to automatically generate
+# dependency information.
+#
+# The Initial Developer of the Original Code is
+#   Mozilla Foundation.
+# Portions created by the Initial Developer are Copyright (C) 2010
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#   Ted Mielczarek <ted@mielczarek.org>
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either the GNU General Public License Version 2 or later (the "GPL"), or
+# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+from __future__ import with_statement
+import os, platform, subprocess, sys, threading, time
+from win32 import procmem
+
+def measure_vsize_threadfunc(proc, output_file):
+    """
+    Measure the virtual memory usage of |proc| at regular intervals
+    until it exits, then print the maximum value and write it to
+    |output_file|.
+    """
+    maxvsize = 0
+    while proc.returncode is None:
+        maxvsize, vsize = procmem.get_vmsize(proc._handle)
+        time.sleep(0.5)
+    print "linker max virtual size: %d" % maxvsize
+    with open(output_file, "w") as f:
+        f.write("%d\n" % maxvsize)
+
+def measure_link_vsize(output_file, args):
+    """
+    Execute |args|, and measure the maximum virtual memory usage of the process,
+    printing it to stdout when finished.
+    """
+    proc = subprocess.Popen(args)
+    t = threading.Thread(target=measure_vsize_threadfunc,
+                         args=(proc, output_file))
+    t.start()
+    # Wait for the linker to finish.
+    exitcode = proc.wait()
+    # ...and then wait for the background thread to finish.
+    t.join()
+    return exitcode
+
+if __name__ == "__main__":
+    if platform.system() != "Windows":
+        print >>sys.stderr, "link.py is only for use on Windows!"
+        sys.exit(1)
+    if len(sys.argv) < 3:
+        print >>sys.stderr, "Usage: link.py <output filename> <commandline>"
+        sys.exit(1)
+    sys.exit(measure_link_vsize(sys.argv[1], sys.argv[2:]))

new file mode 100644

new file mode 100644
--- /dev/null
+++ b/build/win32/procmem.py
@@ -0,0 +1,82 @@
+# ***** BEGIN LICENSE BLOCK *****
+# Version: MPL 1.1/GPL 2.0/LGPL 2.1
+#
+# The contents of this file are subject to the Mozilla Public License Version
+# 1.1 (the "License"); you may not use this file except in compliance with
+# the License. You may obtain a copy of the License at
+# http://www.mozilla.org/MPL/
+#
+# Software distributed under the License is distributed on an "AS IS" basis,
+# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+# for the specific language governing rights and limitations under the
+# License.
+#
+# The Original Code is cl.py: a python wrapper for cl to automatically generate
+# dependency information.
+#
+# The Initial Developer of the Original Code is
+#   Mozilla Foundation.
+# Portions created by the Initial Developer are Copyright (C) 2010
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#   Ted Mielczarek <ted@mielczarek.org>
+#
+# Alternatively, the contents of this file may be used under the terms of
+# either the GNU General Public License Version 2 or later (the "GPL"), or
+# the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+# in which case the provisions of the GPL or the LGPL are applicable instead
+# of those above. If you wish to allow use of your version of this file only
+# under the terms of either the GPL or the LGPL, and not to allow others to
+# use your version of this file under the terms of the MPL, indicate your
+# decision by deleting the provisions above and replace them with the notice
+# and other provisions required by the GPL or the LGPL. If you do not delete
+# the provisions above, a recipient may use your version of this file under
+# the terms of any one of the MPL, the GPL or the LGPL.
+#
+# ***** END LICENSE BLOCK *****
+
+import os, sys, ctypes, ctypes.wintypes
+
+class VM_COUNTERS(ctypes.Structure):
+    _fields_ = [("PeakVirtualSize", ctypes.wintypes.ULONG),
+                ("VirtualSize", ctypes.wintypes.ULONG),
+                ("PageFaultCount", ctypes.wintypes.ULONG),
+                ("PeakWorkingSetSize", ctypes.wintypes.ULONG),
+                ("WorkingSetSize", ctypes.wintypes.ULONG),
+                ("QuotaPeakPagedPoolUsage", ctypes.wintypes.ULONG),
+                ("QuotaPagedPoolUsage", ctypes.wintypes.ULONG),
+                ("QuotaPeakNonPagedPoolUsage", ctypes.wintypes.ULONG),
+                ("QuotaNonPagedPoolUsage", ctypes.wintypes.ULONG),
+                ("PagefileUsage", ctypes.wintypes.ULONG),
+                ("PeakPagefileUsage", ctypes.wintypes.ULONG)
+                ]
+
+def get_vmsize(handle):
+    """
+    Return (peak_virtual_size, virtual_size) for the process |handle|.
+    """
+    ProcessVmCounters = 3
+    vmc = VM_COUNTERS()
+    if ctypes.windll.ntdll.NtQueryInformationProcess(int(handle),
+                                                     ProcessVmCounters,
+                                                     ctypes.byref(vmc),
+                                                     ctypes.sizeof(vmc),
+                                                     None) == 0:
+       return (vmc.PeakVirtualSize, vmc.VirtualSize)
+
+    return (-1, -1)
+
+if __name__ == '__main__':
+    PROCESS_QUERY_INFORMATION = 0x0400
+    for pid in sys.argv[1:]:
+        handle = ctypes.windll.kernel32.OpenProcess(PROCESS_QUERY_INFORMATION,
+                                                    0, # no inherit
+                                                    int(pid))
+        if handle:
+            print "Process %s:" % pid
+            vsize, peak_vsize = get_vmsize(handle)
+            print "peak vsize: %d" % peak_vsize
+            ctypes.windll.kernel32.CloseHandle(handle)
+        else:
+            print "Couldn't open process %s" % pid

--- a/toolkit/library/Makefile.in
+++ b/toolkit/library/Makefile.in
@@ -239,8 +239,13 @@ ifeq ($(OS_ARCH),OpenBSD)
 EXTRA_DSO_LDOPTS += -lkrb5 -lcrypto
 endif
 
 ifdef MOZ_DEBUG
 ifdef ENABLE_TESTS
 DEFINES += -DENABLE_LAYOUTDEBUG
 endif
 endif
+
+ifeq (WINNT_1,$(OS_TARGET)_$(MOZ_PROFILE_USE))
+# Wrap linker to measure peak virtual memory usage.
+LD := $(PYTHON) $(topsrcdir)/build/link.py $(CURDIR)/linker-vsize $(LD)
+endif