[tracing]: Add v8 unwinder to tracing sampler.

Track global pointer to main thread sampler to access from
ChromeContentRendererClient.

Bug: 1077046
Change-Id: Icf575c7a03905c844ce2bd8065129a0df341a9a6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2251087Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Reviewed-by: oysteine <oysteine@chromium.org>
Commit-Queue: Etienne Pierre-Doray <etiennep@chromium.org>
Cr-Commit-Position: refs/heads/master@{#783651}

chrome/renderer/DEPS

@@ -70,6 +70,7 @@ include_rules = [
   "+ppapi/shared_impl",
   "+services/network/public/cpp",
   "+services/network/public/mojom",
+  "+services/tracing/public/cpp",
   "+skia",
   "+storage/common",
   "+third_party/blink/public/mojom",

chrome/renderer/chrome_content_renderer_client.cc

@@ -128,6 +128,7 @@
 #include "printing/buildflags/buildflags.h"
 #include "services/network/public/cpp/is_potentially_trustworthy.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
+#include "services/tracing/public/cpp/stack_sampling/tracing_sampler_profiler.h"
 #include "third_party/blink/public/common/associated_interfaces/associated_interface_provider.h"
 #include "third_party/blink/public/common/features.h"
 #include "third_party/blink/public/common/privacy_budget/identifiability_study_settings.h"
@@ -356,6 +357,11 @@ void ChromeContentRendererClient::RenderThreadStarted() {
   main_thread_profiler_->SetAuxUnwinderFactory(base::BindRepeating(
       &CreateV8Unwinder, base::Unretained(v8::Isolate::GetCurrent())));
 
+  // In the case of single process mode, the v8 unwinding will not work.
+  tracing::TracingSamplerProfiler::SetAuxUnwinderFactoryOnMainThread(
+      base::BindRepeating(&CreateV8Unwinder,
+                          base::Unretained(v8::Isolate::GetCurrent())));
+
   thread->SetRendererProcessType(
       IsStandaloneContentExtensionProcess()
           ? blink::scheduler::WebRendererProcessType::kExtensionRenderer

services/tracing/public/cpp/stack_sampling/tracing_sampler_profiler.cc

@@ -58,6 +58,9 @@ namespace tracing {
 
 namespace {
 
+// Pointer to the main thread instance, if any.
+TracingSamplerProfiler* g_main_thread_instance = nullptr;
+
 class TracingSamplerProfilerDataSource
     : public PerfettoTracedProcess::DataSourceBase {
  public:
@@ -553,6 +556,11 @@ TracingSamplerProfiler::CreateOnMainThread() {
   InitializeLoaderLockSampling();
   profiler->EnableLoaderLockSampling();
 #endif
+  // If running in single process mode, there may be multiple "main thread"
+  // profilers created. In this case, we assume the first created one is the
+  // browser one.
+  if (!g_main_thread_instance)
+    g_main_thread_instance = profiler.get();
   return profiler;
 }
 
@@ -577,6 +585,12 @@ void TracingSamplerProfiler::RegisterDataSource() {
       TracingSamplerProfilerDataSource::Get());
 }
 
+void TracingSamplerProfiler::SetAuxUnwinderFactoryOnMainThread(
+    const base::RepeatingCallback<std::unique_ptr<base::Unwinder>()>& factory) {
+  DCHECK(g_main_thread_instance);
+  g_main_thread_instance->SetAuxUnwinderFactory(factory);
+}
+
 // static
 void TracingSamplerProfiler::StartTracingForTesting(
     PerfettoProducer* producer) {
@@ -615,6 +629,16 @@ TracingSamplerProfiler::TracingSamplerProfiler(
 
 TracingSamplerProfiler::~TracingSamplerProfiler() {
   TracingSamplerProfilerDataSource::Get()->UnregisterProfiler(this);
+  if (g_main_thread_instance == this)
+    g_main_thread_instance = nullptr;
+}
+
+void TracingSamplerProfiler::SetAuxUnwinderFactory(
+    const base::RepeatingCallback<std::unique_ptr<base::Unwinder>()>& factory) {
+  base::AutoLock lock(lock_);
+  aux_unwinder_factory_ = factory;
+  if (profiler_)
+    profiler_->AddAuxUnwinder(aux_unwinder_factory_.Run());
 }
 
 void TracingSamplerProfiler::SetSampleCallbackForTesting(
@@ -675,6 +699,8 @@ void TracingSamplerProfiler::StartTracing(
 #else   // defined(OS_ANDROID)
   profiler_ = std::make_unique<base::StackSamplingProfiler>(
       sampled_thread_token_, params, std::move(profile_builder));
+  if (aux_unwinder_factory_)
+    profiler_->AddAuxUnwinder(aux_unwinder_factory_.Run());
   profiler_->Start();
 #endif  // defined(OS_ANDROID)
 }

services/tracing/public/cpp/stack_sampling/tracing_sampler_profiler.h

@@ -17,6 +17,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/profiler/sampling_profiler_thread_token.h"
 #include "base/profiler/stack_sampling_profiler.h"
+#include "base/profiler/unwinder.h"
 #include "base/sequence_checker.h"
 #include "base/threading/platform_thread.h"
 #include "build/build_config.h"
@@ -150,6 +151,12 @@ class COMPONENT_EXPORT(TRACING_CPP) TracingSamplerProfiler {
   // Registers the TracingSamplerProfiler as a Perfetto data source
   static void RegisterDataSource();
 
+  // Sets a callback to create auxiliary unwinders on the main thread profiler,
+  // for handling additional, non-native-code unwind scenarios.
+  static void SetAuxUnwinderFactoryOnMainThread(
+      const base::RepeatingCallback<std::unique_ptr<base::Unwinder>()>&
+          factory);
+
   // For tests.
   static void SetupStartupTracingForTesting();
   static void DeleteOnChildThreadForTesting();
@@ -173,6 +180,13 @@ class COMPONENT_EXPORT(TRACING_CPP) TracingSamplerProfiler {
       base::SamplingProfilerThreadToken sampled_thread_token);
   virtual ~TracingSamplerProfiler();
 
+  // Sets a callback to create auxiliary unwinders, for handling additional,
+  // non-native-code unwind scenarios. Currently used to support
+  // unwinding V8 JavaScript frames.
+  void SetAuxUnwinderFactory(
+      const base::RepeatingCallback<std::unique_ptr<base::Unwinder>()>&
+          factory);
+
   // The given callback will be called for every received sample, and can be
   // called on any thread. Must be called before tracing is started.
   void SetSampleCallbackForTesting(
@@ -185,6 +199,9 @@ class COMPONENT_EXPORT(TRACING_CPP) TracingSamplerProfiler {
  private:
   const base::SamplingProfilerThreadToken sampled_thread_token_;
 
+  base::RepeatingCallback<std::unique_ptr<base::Unwinder>()>
+      aux_unwinder_factory_;
+
   base::Lock lock_;
   std::unique_ptr<base::StackSamplingProfiler> profiler_;  // under |lock_|
   TracingProfileBuilder* profile_builder_ = nullptr;