Keep shadow stacks to help heap checker unwind without frame pointers

base/allocator/allocator.gyp

 # Copyright (c) 2009 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'jemalloc_dir': '../../third_party/jemalloc/chromium',
     'tcmalloc_dir': '../../third_party/tcmalloc/chromium',
   },
   'targets': [
@@ skipping 336 matching lines @@
             '<(tcmalloc_dir)/src/tcmalloc.cc',
           ],
           'cflags': [
             '-DTCMALLOC_FOR_DEBUGALLOCATION',
           ],
         }, { # linux_use_debugallocation != 1
           'sources!': [
             '<(tcmalloc_dir)/src/debugallocation.cc',
           ],
         }],
+        [ 'linux_keep_shadow_stacks==1', {
+          'sources': [
+            '<(tcmalloc_dir)/src/linux_shadow_stacks.cc',
+            '<(tcmalloc_dir)/src/linux_shadow_stacks.h',
+            '<(tcmalloc_dir)/src/stacktrace_shadow-inl.h',
+          ],
+          'cflags': [
+            '-finstrument-functions',
+            '-DKEEP_SHADOW_STACKS',
+          ],
+        }],
         [ 'linux_use_heapchecker==0', {
           # Do not compile and link the heapchecker source.
           'sources!': [
             '<(tcmalloc_dir)/src/heap-checker-bcad.cc',
             '<(tcmalloc_dir)/src/heap-checker.cc',
           ],
           # Disable the heap checker in tcmalloc.
           'cflags': [
             '-DNO_HEAP_CHECK',
           ],
@@ skipping 46 matching lines @@
       ],
     }],
   ],
 }
 
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