Heap Profiler: Add trace category group names as type names for allocations

base/trace_event/heap_profiler_allocation_context_tracker.cc

 // Copyright 2015 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 "base/trace_event/heap_profiler_allocation_context_tracker.h"
 
 #include <algorithm>
 #include <iterator>
 
 #include "base/atomicops.h"
@@ skipping 90 matching lines @@
   // a TLS instance yet.
   if (mode != CaptureMode::DISABLED && !g_tls_alloc_ctx_tracker.initialized())
     g_tls_alloc_ctx_tracker.Initialize(DestructAllocationContextTracker);
 
   // Release ordering ensures that when a thread observes |capture_mode_| to
   // be true through an acquire load, the TLS slot has been initialized.
   subtle::Release_Store(&capture_mode_, static_cast<int32_t>(mode));
 }
 
 void AllocationContextTracker::PushPseudoStackFrame(
-    const char* trace_event_name) {
+    AllocationContextTracker::PseudoStackFrame stack_frame) {
   // Impose a limit on the height to verify that every push is popped, because
   // in practice the pseudo stack never grows higher than ~20 frames.
   if (pseudo_stack_.size() < kMaxStackDepth)
-    pseudo_stack_.push_back(trace_event_name);
+    pseudo_stack_.push_back(stack_frame);
   else
     NOTREACHED();
 }
 
 void AllocationContextTracker::PopPseudoStackFrame(
-    const char* trace_event_name) {
+    AllocationContextTracker::PseudoStackFrame stack_frame) {
   // Guard for stack underflow. If tracing was started with a TRACE_EVENT in
   // scope, the frame was never pushed, so it is possible that pop is called
   // on an empty stack.
   if (pseudo_stack_.empty())
     return;
 
   // Assert that pushes and pops are nested correctly. This DCHECK can be
   // hit if some TRACE_EVENT macro is unbalanced (a TRACE_EVENT_END* call
   // without a corresponding TRACE_EVENT_BEGIN).
-  DCHECK_EQ(trace_event_name, pseudo_stack_.back())
+  DCHECK(stack_frame == pseudo_stack_.back())
       << "Encountered an unmatched TRACE_EVENT_END";
 
   pseudo_stack_.pop_back();
 }
 
 void AllocationContextTracker::PushCurrentTaskContext(const char* context) {
   DCHECK(context);
   if (task_contexts_.size() < kMaxTaskDepth)
     task_contexts_.push_back(context);
   else
@@ skipping 44 matching lines @@
     *backtrace++ = StackFrame::FromThreadName(thread_name_);
   }
 
   switch (mode) {
     case CaptureMode::DISABLED:
       {
         break;
       }
     case CaptureMode::PSEUDO_STACK:
       {
-        for (const char* event_name: pseudo_stack_) {
+        for (const PseudoStackFrame& stack_frame : pseudo_stack_) {
           if (backtrace == backtrace_end) {
             break;
           }
-          *backtrace++ = StackFrame::FromTraceEventName(event_name);
+          *backtrace++ =
+              StackFrame::FromTraceEventName(stack_frame.trace_event_name);
         }
         break;
       }
     case CaptureMode::NATIVE_STACK:
       {
         // Backtrace contract requires us to return bottom frames, i.e.
         // from main() and up. Stack unwinding produces top frames, i.e.
         // from this point and up until main(). We request many frames to
         // make sure we reach main(), and then copy bottom portion of them.
         const void* frames[128];
@@ skipping 19 matching lines @@
           *backtrace++ = StackFrame::FromProgramCounter(frame);
         }
         break;
       }
   }
 
   ctx.backtrace.frame_count = backtrace - std::begin(ctx.backtrace.frames);
 
   // TODO(ssid): Fix crbug.com/594803 to add file name as 3rd dimension
   // (component name) in the heap profiler and not piggy back on the type name.
-  ctx.type_name = task_contexts_.empty() ? nullptr : task_contexts_.back();
+  if (!task_contexts_.empty()) {
+    ctx.type_name = task_contexts_.back();
+  } else if (!pseudo_stack_.empty()) {
+    // If task context was unavailable, then the category names are taken from
+    // trace events.
+    ctx.type_name = pseudo_stack_.back().trace_event_category;
+  }
 
   return ctx;
 }
 
 }  // namespace trace_event
 }  // namespace base