linux: TCMalloc-based C++ heap profiler.

Requires compiling with linux_use_tcmalloc=1.

When enabled by --heap-profiler flag in test_shell exposes
chromium.HeapProfiler object to JavaScript. The object has three
methods:
o start() -- starts profiling
o dump() -- dumps data accumulated since start() to file
named like chromium-YYYY-MM-DD-TS.heap
o stop() -- stops profiling.

Output can be analyzed by third_party/tcmalloc/tcmalloc/src/pprof.
For example:
$ third_party/tcmalloc/tcmalloc/src/pprof \
sconsbuild/Release/test_shell \
chromium-2009-11-06-1234567890.heap

See http://code.google.com/p/google-perftools/ for details on how to
use pprof.

Patch contributed by vitalyr@chromium.org.  Original review at
http://codereview.chromium.org/377010/show.

TBR=vitalyr

Review URL: http://codereview.chromium.org/390015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31688 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 134 insertions, 0 deletions

diff --git a/webkit/extensions/v8/heap_profiler_extension.cc b/webkit/extensions/v8/heap_profiler_extension.cc
new file mode 100644
index 0000000..058a5c2
--- /dev/null
+++ b/webkit/extensions/v8/heap_profiler_extension.cc
@@ -0,0 +1,111 @@
+// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "webkit/extensions/v8/heap_profiler_extension.h"
+
+#include "base/basictypes.h"
+
+#if defined(LINUX_USE_TCMALLOC)
+#include "third_party/tcmalloc/tcmalloc/src/google/heap-profiler.h"
+#endif
+
+namespace extensions_v8 {
+
+namespace {
+
+const char kHeapProfilerExtensionName[] = "v8/HeapProfiler";
+
+class HeapProfilerWrapper : public v8::Extension {
+ public:
+  HeapProfilerWrapper()
+      : v8::Extension(kHeapProfilerExtensionName,
+                      "if (typeof(chromium) == 'undefined') {"
+                      "  chromium = {};"
+                      "}"
+                      "(function() {"
+                      "  native function HeapProfilerStart();"
+                      "  native function HeapProfilerStop();"
+                      "  native function HeapProfilerDump();"
+                      "  chromium.HeapProfiler = {};"
+                      "  chromium.HeapProfiler.start = function(opt_prefix) {"
+                      "    var prefix = opt_prefix;"
+                      "    if (!prefix) {"
+                      "      var d = new Date();"
+                      "      prefix = \"chromium-\" + "
+                      "               (1900 + d.getYear()) + "
+                      "               \"-\" + d.getMonth() + "
+                      "               \"-\" + d.getDay() + "
+                      "               \"-\" + d.getTime();"
+                      "    }"
+                      "    HeapProfilerStart(prefix);"
+                      "  };"
+                      "  chromium.HeapProfiler.stop = function() {"
+                      "    HeapProfilerStop();"
+                      "  };"
+                      "  chromium.HeapProfiler.dump = function(opt_reason) {"
+                      "    HeapProfilerDump(opt_reason || \"\");"
+                      "  };"
+                      "})();") {}
+
+  virtual v8::Handle<v8::FunctionTemplate> GetNativeFunction(
+      v8::Handle<v8::String> name) {
+    if (name->Equals(v8::String::New("HeapProfilerStart"))) {
+      return v8::FunctionTemplate::New(HeapProfilerStart);
+    } else if (name->Equals(v8::String::New("HeapProfilerStop"))) {
+      return v8::FunctionTemplate::New(HeapProfilerStop);
+    } else if (name->Equals(v8::String::New("HeapProfilerDump"))) {
+      return v8::FunctionTemplate::New(HeapProfilerDump);
+    }
+    return v8::Handle<v8::FunctionTemplate>();
+  }
+
+#if defined(LINUX_USE_TCMALLOC)
+  static v8::Handle<v8::Value> HeapProfilerStart(const v8::Arguments& args) {
+    if (args.Length() >= 1 && args[0]->IsString()) {
+      v8::Local<v8::String> js_prefix = args[0]->ToString();
+      char prefix[256];
+      js_prefix->WriteAscii(prefix, 0, arraysize(prefix) - 1);
+      ::HeapProfilerStart(prefix);
+    }
+    return v8::Undefined();
+  }
+
+  static v8::Handle<v8::Value> HeapProfilerStop(const v8::Arguments& args) {
+    ::HeapProfilerStop();
+    return v8::Undefined();
+  }
+
+  static v8::Handle<v8::Value> HeapProfilerDump(const v8::Arguments& args) {
+    if (args.Length() >= 1 && args[0]->IsString()) {
+      v8::Local<v8::String> js_reason = args[0]->ToString();
+      char reason[256];
+      js_reason->WriteAscii(reason, 0, arraysize(reason) - 1);
+      ::HeapProfilerDump(reason);
+    }
+    return v8::Undefined();
+  }
+
+#else
+
+  static v8::Handle<v8::Value> HeapProfilerStart(const v8::Arguments& args) {
+    return v8::Undefined();
+  }
+
+  static v8::Handle<v8::Value> HeapProfilerStop(const v8::Arguments& args) {
+    return v8::Undefined();
+  }
+
+  static v8::Handle<v8::Value> HeapProfilerDump(const v8::Arguments& args) {
+    return v8::Undefined();
+  }
+#endif
+};
+
+}  // namespace
+
+v8::Extension* HeapProfilerExtension::Get() {
+  return new HeapProfilerWrapper;
+}
+
+}  // namespace extensions_v8
diff --git a/webkit/extensions/v8/heap_profiler_extension.h b/webkit/extensions/v8/heap_profiler_extension.h
new file mode 100644
index 0000000..8bdbf90
--- /dev/null
+++ b/webkit/extensions/v8/heap_profiler_extension.h
@@ -0,0 +1,23 @@
+// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// HeapProfilerExtension is a V8 extension to expose a JS function for
+// dumping native heap profiles.  This should only be used for
+// debugging.
+
+#ifndef WEBKIT_EXTENSIONS_V8_HEAP_PROFILER_EXTENSION_H_
+#define WEBKIT_EXTENSIONS_V8_HEAP_PROFILER_EXTENSION_H_
+
+#include "v8/include/v8.h"
+
+namespace extensions_v8 {
+
+class HeapProfilerExtension {
+ public:
+  static v8::Extension* Get();
+};
+
+}  // namespace extensions_v8
+
+#endif  // WEBKIT_EXTENSIONS_V8_HEAP_PROFILER_EXTENSION_H_