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

[Alexander Potapenko]

LGTM with nits.

================
Comment at: lib/asan/asan_debugging.cc:72
@@ +71,3 @@
+    *shadow_scale = SHADOW_SCALE;
+
+  if (shadow_offset)
----------------
Nit: spare newline.
In general it's better when more code fits on the screen, and this function is small enough to comprehend without that newline.

================
Comment at: test/asan/TestCases/debug_mapping.cc:1
@@ +1,2 @@
+// XXX
+// RUN: %clangxx_asan -O %s -o %t
----------------
?

http://reviews.llvm.org/D4466