Adds TCMalloc support for Android.

third_party/tcmalloc/chromium/src/getpc.h

 // Copyright (c) 2005, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 // notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
@@ skipping 44 matching lines @@
 //#define _XOPEN_SOURCE 500
 
 #include <string.h>         // for memcmp
 #if defined(HAVE_SYS_UCONTEXT_H)
 #include <sys/ucontext.h>
 #elif defined(HAVE_UCONTEXT_H)
 #include <ucontext.h>       // for ucontext_t (and also mcontext_t)
 #elif defined(HAVE_CYGWIN_SIGNAL_H)
 #include <cygwin/signal.h>
 typedef ucontext ucontext_t;
+#elif defined(__ANDROID__)
+#include <unwind.h>
 #endif
 
 
 // Take the example where function Foo() calls function Bar().  For
 // many architectures, Bar() is responsible for setting up and tearing
 // down its own stack frame.  In that case, it's possible for the
 // interrupt to happen when execution is in Bar(), but the stack frame
 // is not properly set up (either before it's done being set up, or
 // after it's been torn down but before Bar() returns).  In those
 // cases, the stack trace cannot see the caller function anymore.
@@ skipping 27 matching lines @@
   int return_sp_offset;
 };
 
 
 // The dereferences needed to get the PC from a struct ucontext were
 // determined at configure time, and stored in the macro
 // PC_FROM_UCONTEXT in config.h.  The only thing we need to do here,
 // then, is to do the magic call-unrolling for systems that support it.
 
 // -- Special case 1: linux x86, for which we have CallUnrollInfo
 #if defined(__linux) && defined(__i386) && defined(__GNUC__)

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

I'm not sure if we have x86 Android, but we may want !defined(__ANDROID__) here?

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

we do have x86, added the guard here.

 static const CallUnrollInfo callunrollinfo[] = {
   // Entry to a function:  push %ebp;  mov  %esp,%ebp
   // Top-of-stack contains the caller IP.
   { 0,
     {0x55, 0x89, 0xe5}, 3,
     0
   },
   // Entry to a function, second instruction:  push %ebp;  mov  %esp,%ebp
   // Top-of-stack contains the old frame, caller IP is +4.
   { -1,
     {0x55, 0x89, 0xe5}, 3,
     4
   },
   // Return from a function: RET.
   // Top-of-stack contains the caller IP.
   { 0,
     {0xc3}, 1,
     0
   }
 };
 
 inline void* GetPC(const ucontext_t& signal_ucontext) {
   // See comment above struct CallUnrollInfo.  Only try instruction
   // flow matching if both eip and esp looks reasonable.
   const int eip = signal_ucontext.uc_mcontext.gregs[REG_EIP];
   const int esp = signal_ucontext.uc_mcontext.gregs[REG_ESP];
   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.
         void **retaddr = (void**)(esp + callunrollinfo[i].return_sp_offset);
         return *retaddr;
       }
     }
   }
   return (void*)eip;
 }
@@ skipping 11 matching lines @@
 
 #include "base/logging.h"   // for RAW_LOG
 #ifndef HAVE_CYGWIN_SIGNAL_H
 typedef int ucontext_t;
 #endif
 
 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
 }
 
 #endif
 
 #endif  // BASE_GETPC_H_