Bug 809317 - Part 1: Provide a pseudo stack implementation of SAMPLER_PRINT_LOCATION. r=ehsan

--HG--
extra : rebase_source : ba956341ba6115f5c0f60a067c46aee45d29724b

tools/profiler/TableTicker.cpp

@@ -143,8 +143,6 @@ public:
 
   friend std::ostream& operator<<(std::ostream& stream, const ProfileEntry& entry);
 
-private:
-  friend class ThreadProfile;
   union {
     const char* mTagData;
     char mTagChars[sizeof(void*)];
@@ -157,6 +155,8 @@ private:
   char mTagName;
 };
 
+typedef void (*IterateTagsCallback)(const ProfileEntry& entry, const char* tagStringData);
+
 #define PROFILE_MAX_ENTRY 100000
 class ThreadProfile
 {
@@ -280,6 +280,33 @@ public:
 
   friend std::ostream& operator<<(std::ostream& stream, const ThreadProfile& profile);
 
+  void IterateTags(IterateTagsCallback aCallback)
+  {
+    MOZ_ASSERT(aCallback);
+
+    int readPos = mReadPos;
+    while (readPos != mLastFlushPos) {
+      // Number of tag consumed
+      int incBy = 1;
+      const ProfileEntry& entry = mEntries[readPos];
+
+      // Read ahead to the next tag, if it's a 'd' tag process it now
+      const char* tagStringData = entry.mTagData;
+      int readAheadPos = (readPos + 1) % mEntrySize;
+      char tagBuff[DYNAMIC_MAX_STRING];
+      // Make sure the string is always null terminated if it fills up DYNAMIC_MAX_STRING-2
+      tagBuff[DYNAMIC_MAX_STRING-1] = '\0';
+
+      if (readAheadPos != mLastFlushPos && mEntries[readAheadPos].mTagName == 'd') {
+        tagStringData = processDynamicTag(readPos, &incBy, tagBuff);
+      }
+
+      aCallback(entry, tagStringData);
+
+      readPos = (readPos + incBy) % mEntrySize;
+    }
+  }
+
   JSObject *ToJSObject(JSContext *aCx)
   {
     JSObjectBuilder b(aCx);
@@ -1193,3 +1220,31 @@ void mozilla_sampler_frame_number(int frameNumber)
 {
   sFrameNumber = frameNumber;
 }
+
+void print_callback(const ProfileEntry& entry, const char* tagStringData) {
+  switch (entry.mTagName) {
+    case 's':
+    case 'c':
+      printf_stderr("  %s\n", tagStringData);
+  }
+}
+
+void mozilla_sampler_print_location()
+{
+  if (!stack_key_initialized)
+    mozilla_sampler_init();
+
+  ProfileStack *stack = tlsStack.get();
+  if (!stack) {
+    MOZ_ASSERT(false);
+    return;
+  }
+
+  ThreadProfile threadProfile(1000, stack);
+  doSampleStackTrace(stack, threadProfile, NULL);
+
+  threadProfile.flush();
+
+  printf_stderr("Backtrace:\n");
+  threadProfile.IterateTags(print_callback);
+}

tools/profiler/sampler.h

@@ -80,6 +80,9 @@
 #define SAMPLE_LABEL_FN(name_space, info)
 #define SAMPLE_MARKER(info)
 
+// Tracing features
+#define SAMPLER_PRINT_LOCATION()
+
 #endif
 
 #endif // ifndef SAMPLER_H

tools/profiler/sps_sampler.h

@@ -64,6 +64,8 @@ extern bool stack_key_initialized;
 #define SAMPLE_LABEL_PRINTF(name_space, info, ...) mozilla::SamplerStackFramePrintfRAII SAMPLER_APPEND_LINE_NUMBER(sampler_raii)(name_space "::" info, __LINE__, __VA_ARGS__)
 #define SAMPLE_MARKER(info) mozilla_sampler_add_marker(info)
 
+#define SAMPLER_PRINT_LOCATION() mozilla_sampler_print_location()
+
 /* we duplicate this code here to avoid header dependencies
  * which make it more difficult to include in other places */
 #if defined(_M_X64) || defined(__x86_64__)
@@ -171,6 +173,8 @@ JSObject *mozilla_sampler_get_profile_data(JSContext *aCx);
 const char** mozilla_sampler_get_features();
 void mozilla_sampler_init();
 
+void mozilla_sampler_print_location();
+
 namespace mozilla {
 
 class NS_STACK_CLASS SamplerStackFrameRAII {