[PATCH] [compiler-rt] Add ASan debugging API to get malloc/free stack traces and shadow memory mapping info

[Kostya Serebryany]

LGTM with two small nits.

================
Comment at: lib/asan/asan_debugging.cc:22
@@ +21,3 @@
+
+using namespace __asan;
+
----------------
move this below, right before the first SANITIZER_INTERFACE_ATTRIBUTE

================
Comment at: lib/asan/asan_debugging.cc:70
@@ +69,3 @@
+void __asan_get_shadow_mapping(uptr *shadow_scale, uptr *shadow_offset) {
+  if (shadow_scale) {
+    *shadow_scale = SHADOW_SCALE;
----------------
we tend to omit {} in such simple expressions

http://reviews.llvm.org/D4466