Implement OS::DumpBacktrace() on FreeBSD.

src/platform-freebsd.cc

 // Copyright 2012 the V8 project authors. 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
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 180 matching lines @@
 #if (defined(__arm__) || defined(__thumb__))
 # if defined(CAN_USE_ARMV5_INSTRUCTIONS)
   asm("bkpt 0");
 # endif
 #else
   asm("int $3");
 #endif
 }
 
 
+void OS::DumpBacktrace() {
+  void* trace[100];
+  int size = backtrace(trace, ARRAY_SIZE(trace));
+  char** symbols = backtrace_symbols(trace, size);
+  fprintf(stderr, "\n==== C stack trace ===============================\n\n");
+  if (size == 0) {
+    fprintf(stderr, "(empty)\n");
+  } else if (symbols == NULL) {
+    fprintf(stderr, "(no symbols)\n");
+  } else {
+    for (int i = 1; i < size; ++i) {
+      fprintf(stderr, "%2d: ", i);
+      char mangled[201];
+      if (sscanf(symbols[i], "%*[^(]%*[(]%200[^)+]", mangled) == 1) {  // NOLINT
+        fprintf(stderr, "%s\n", mangled);
+      } else {
+        fprintf(stderr, "??\n");
+      }
+    }
+  }
+  fflush(stderr);
+  free(symbols);
+}
+
+
 class PosixMemoryMappedFile : public OS::MemoryMappedFile {
  public:
   PosixMemoryMappedFile(FILE* file, void* memory, int size)
     : file_(file), memory_(memory), size_(size) { }
   virtual ~PosixMemoryMappedFile();
   virtual void* memory() { return memory_; }
   virtual int size() { return size_; }
  private:
   FILE* file_;
   void* memory_;
@@ skipping 651 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal