Explicitly specify whether to emit frame pointers by default.

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 08e9a9ef988737dcc6eaedee39e7b0021f20df0b..6056d6ec58bd9dd55d4f0a30686bdcc453980bd7 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -1381,18 +1381,22 @@ if (is_win) {
 }
 
 config("default_stack_frames") {
-  if (is_posix && !(is_mac || is_ios)) {
-    if (using_sanitizer || enable_profiling || is_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).
+  if (is_posix) {
+    if (enabled_frame_pointers) {
       cflags = [ "-fno-omit-frame-pointer" ]
-    } else if (is_android) {
+    } else {
       cflags = [ "-fomit-frame-pointer" ]
     }
   }
+  # On Windows, the flag to enable framepointers "/Oy-" must always come after
+  # the optimization flag [e.g. "/O2"]. The optimization flag is set by one of
+  # the "optimize" configs, see rest of this file. The ordering that cflags are
+  # applied is well-defined by the GN spec, and there is no way to ensure that
+  # cflags set by "default_stack_frames" is applied after those set by an
+  # "optimize" confnig. Similarly, there is no way to propagate state from this

[brettw, 2017/04/03 21:17:42]

confnig spelling

+  # config into the "optimize" config. We always apply the "/Oy-" config in the
+  # definition for common_optimize_on_cflags definition, even though this may
+  # not be correct.
 }
 
 # Default "optimization on" config.