Explicitly ask for stack frame pointers on Debug posix builds.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 214 matching lines @@
     # when turning clang on or off. (defines are passed via the command line,
     # and build system rebuild things when their commandline changes). Nothing
     # should ever read this define.
     defines += [ "CR_CLANG_REVISION=$clang_revision" ]
   }
 
   # Non-Mac Posix compiler flags setup.
   # -----------------------------------
   if (is_posix && !(is_mac || is_ios)) {
     if (enable_profiling) {
-      # Explicitly ask for frame pointers. Otherwise they are omitted when
-      # any optimization level is used (and Android debug builds use -Os).
-      cflags += [ "-fno-omit-frame-pointer" ]
       if (!is_debug) {
         cflags += [ "-g" ]
 
         if (enable_full_stack_frames_for_profiling) {
           cflags += [
             "-fno-inline",
             "-fno-optimize-sibling-calls",
           ]
         }
       }
@@ skipping 983 matching lines @@
     ]
     if (full_wpo_on_official) {
       arflags = [ "/LTCG" ]
     }
   }
 } else {
   common_optimize_on_cflags = []
   common_optimize_on_ldflags = []
 
   if (is_android) {
-    # We don't omit frame pointers on arm64 since they are required
-    # to correctly unwind stackframes which contain system library
-    # function frames (crbug.com/391706).
-    if (!using_sanitizer && !enable_profiling && current_cpu != "arm64") {
-      common_optimize_on_cflags += [ "-fomit-frame-pointer" ]
-    }
-
     # TODO(jdduke) Re-enable on mips after resolving linking
     # issues with libc++ (crbug.com/456380).
     if (current_cpu != "mipsel" && current_cpu != "mips64el") {
       common_optimize_on_ldflags += [
         # Warn in case of text relocations.
         "-Wl,--warn-shared-textrel",
       ]
     }
   }
 
@@ skipping 33 matching lines @@
         common_optimize_on_ldflags += [
           "-Wl,--no-as-needed",
           "-lpthread",
         ]
       }
       common_optimize_on_ldflags += [ "-Wl,--as-needed" ]
     }
   }
 }
 
+config("default_stack_frames") {
+  if (is_posix && !(is_mac || is_ios)) {
+    if (using_sanitizer || enable_profiling || is_debug ||

[brettw, 2016/08/24 18:27:02]

This is still different from the old code on Android.

Previously on Android no_optimize would still omit frame pointers unless
!android_full_debug was set (which is what you set when you really want to
debug).

[vmiura, 2016/08/24 18:47:26]

I may be missing a nuance, but I'm intentionally making this change from the old
behavior because omitting frames on Debug can cause flaky crashes in tcmalloc. 
We run standard Debug builds on bots and I don't think we want to change them to
android_full_debug.

+        current_cpu == "arm64") {
+      # Explicitly ask for frame pointers, otherwise:
+      # * Stacks may be missing for sanitizer and profiling builds.
+      # * Debug tcmalloc can crash (crbug.com/636489).
+      # * Stacks may be missing for arm64 crash dumps (crbug.com/391706).
+      cflags = [ "-fno-omit-frame-pointer" ]
+    } else if (is_android) {
+      cflags = [ "-fomit-frame-pointer" ]

[brettw, 2016/08/24 19:30:02]

I mean this line. It used to not set this on the Android debug case when
android_full_debug was set.

[vmiura, 2016/08/24 19:40:16]

Thanks, yeah I think that 'android_full_debug' is only used together with
'is_debug' which triggers config("no_optimize"), so it would use the
-fno-omit-frame-pointer flag.

+    }
+  }
+}
+
 # Default "optimization on" config.
 config("optimize") {
   if (is_win) {
     # TODO(thakis): Remove is_clang here, https://crbug.com/598772
     if (is_official_build && full_wpo_on_official && !is_clang) {
       common_optimize_on_cflags += [
         "/GL",  # Whole program optimization.
 
         # Disable Warning 4702 ("Unreachable code") for the WPO/PGO builds.
         # Probably anything that this would catch that wouldn't be caught in a
@@ skipping 39 matching lines @@
     ]
   } else if (is_android && !android_full_debug) {
     # On Android we kind of optimize some things that don't affect debugging
     # much even when optimization is disabled to get the binary size down.
     cflags = [
       "-Os",
       "-fdata-sections",
       "-ffunction-sections",
     ]
 
-    # We don't omit frame pointers on arm64 since they are required
-    # to correctly unwind stackframes which contain system library
-    # function frames (crbug.com/391706).
-    if (!using_sanitizer && !enable_profiling && current_cpu != "arm64") {
-      cflags += [ "-fomit-frame-pointer" ]
-    }
-
     # Don't use gc-sections since it can cause links to succeed when they
     # actually shouldn't. http://crbug.com/159847
     ldflags = common_optimize_on_ldflags - [ "-Wl,--gc-sections" ]
   } else {
     cflags = [ "-O0" ]
     ldflags = []
   }
 }
 
 # Turns up the optimization level. On Windows, this implies whole program
@@ skipping 191 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }