Adds TCMalloc support for Android.

third_party/tcmalloc/chromium/src/getpc.h

Index: third_party/tcmalloc/chromium/src/getpc.h
diff --git a/third_party/tcmalloc/chromium/src/getpc.h b/third_party/tcmalloc/chromium/src/getpc.h
index 9fb2e162beb22621406918ec017f2dd3bc2ea073..d22cfdbcdff934d930e2ef04970ef72cae02721a 100644
--- a/third_party/tcmalloc/chromium/src/getpc.h
+++ b/third_party/tcmalloc/chromium/src/getpc.h
@@ -62,6 +62,8 @@
 #elif defined(HAVE_CYGWIN_SIGNAL_H)
 #include <cygwin/signal.h>
 typedef ucontext ucontext_t;
+#elif defined(__ANDROID__)
+#include <unwind.h>
 #endif
 
 
@@ -139,7 +141,7 @@ inline void* GetPC(const ucontext_t& signal_ucontext) {
   if ((eip & 0xffff0000) != 0 && (~eip & 0xffff0000) != 0 &&
       (esp & 0xffff0000) != 0) {
     char* eip_char = reinterpret_cast<char*>(eip);
-    for (int i = 0; i < sizeof(callunrollinfo)/sizeof(*callunrollinfo); ++i) {
+    for (int i = 0; i < sizeof(CallUnrollInfo)/sizeof(*callunrollinfo); ++i) {

[Dai Mikurube (NOT FULLTIME), 2013/05/03 08:53:00]

It's necessary?  (Since tcmalloc is a third_party library, I'd like to avoid
unnecessary changes.)

[bulach, 2013/05/07 14:55:51]

Done.

       if (!memcmp(eip_char + callunrollinfo[i].pc_offset,
                   callunrollinfo[i].ins, callunrollinfo[i].ins_size)) {
         // We have a match.
@@ -171,12 +173,22 @@ inline void* GetPC(const struct ucontext_t& signal_ucontext) {
   RAW_LOG(ERROR, "GetPC is not yet implemented on Windows\n");
   return NULL;
 }
+#elif defined(__ANDROID__)
 
+typedef struct _Unwind_Context ucontext_t;
+
+inline void* GetPC(const ucontext_t& signal_ucontext) {
+  // Bionic doesn't export ucontext, see
+  // https://code.google.com/p/android/issues/detail?id=34784.
+  return reinterpret_cast<void*>(_Unwind_GetIP(
+      const_cast<ucontext_t*>(&signal_ucontext)));
+}
+#else
+//
 // Normal cases.  If this doesn't compile, it's probably because
 // PC_FROM_UCONTEXT is the empty string.  You need to figure out
 // the right value for your system, and add it to the list in
 // configure.ac (or set it manually in your config.h).
-#else
 inline void* GetPC(const ucontext_t& signal_ucontext) {
   return (void*)signal_ucontext.PC_FROM_UCONTEXT;   // defined in config.h
 }