Explicitly ask for stack frame pointers on Debug posix builds.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 79723f6cc76c041697955f5c7de91e2935e78aa5..7e65dfa41cf0301123c3af3e376133a59d6eb3fb 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -231,10 +231,13 @@ config("compiler") {
   # 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).
+    if (enable_profiling || is_debug) {
+      # Explicitly ask for frame pointers, otherwise they are omitted when
+      # any optimization level is used (Android debug builds use -Os.)
+      # This prevents stack frames from working when profiling, and can cause
+      # crashes when unwinding stack frames (crbug.com/636489).

[Dirk Pranke, 2016/08/22 20:03:48]

Do we have any idea what the perf impact of -fno-omit-frame-pointer is? I've
been thinking that maybe it should just be on unconditionally in non-official
builds.

Alternatively, we might want to make it be a configurable argument; the goal of
either choice would partially be to make sure stack traces are as
debuggable/useful as possible.

[vmiura, 2016/08/22 20:32:04]

I don't have data but I expect the impact is fairly small.  The
'enable_profiling' flag partly overlaps with that.  Perhaps a follow up?

       cflags += [ "-fno-omit-frame-pointer" ]
+
       if (!is_debug) {
         cflags += [ "-g" ]
 
@@ -1274,6 +1277,13 @@ if (is_win) {
       "-ffunction-sections",
     ]
 
+    if (is_debug) {
+      # Explicitly ask for frame pointers, otherwise they are omitted when
+      # any optimization level is used and can cause crashes when unwinding
+      # stack frames (crbug.com/636489).
+      common_optimize_on_cflags += [ "-fno-omit-frame-pointer" ]
+    }
+
     common_optimize_on_ldflags += [
       # Specifically tell the linker to perform optimizations.
       # See http://lwn.net/Articles/192624/ .