Adds `-ftime-trace` option to clang that produces Chrome `chrome://tracing` compatible JSON profiling output dumps.

This change adds hierarchical "time trace" profiling blocks that can be visualized in Chrome, in a "flame chart" style. Each profiling block can have a "detail" string that for example indicates the file being processed, template name being instantiated, function being optimized etc.

This is taken from GitHub PR: https://github.com/aras-p/llvm-project-20170507/pull/2

Patch by Aras Pranckevičius.

Differential Revision: https://reviews.llvm.org/D58675

llvm-svn: 357340

2 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
index 540cc6f6bc5..e22a62d3777 100644
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -42,6 +42,7 @@
 #include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetMachine.h"
@@ -1382,6 +1383,9 @@ void clang::EmitBackendOutput(DiagnosticsEngine &Diags,
                               const llvm::DataLayout &TDesc, Module *M,
                               BackendAction Action,
                               std::unique_ptr<raw_pwrite_stream> OS) {
+
+  llvm::TimeTraceScope TimeScope("Backend", StringRef(""));
+
   std::unique_ptr<llvm::Module> EmptyModule;
   if (!CGOpts.ThinLTOIndexFile.empty()) {
     // If we are performing a ThinLTO importing compile, load the function index
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 91f162820cb..1a2e420233e 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -58,6 +58,7 @@
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MD5.h"
+#include "llvm/Support/TimeProfiler.h"
 
 using namespace clang;
 using namespace CodeGen;
@@ -2482,6 +2483,9 @@ void CodeGenModule::EmitGlobalDefinition(GlobalDecl GD, llvm::GlobalValue *GV) {
     if (!shouldEmitFunction(GD))
       return;
 
+    llvm::TimeTraceScope TimeScope(
+        "CodeGen Function", [&]() { return FD->getQualifiedNameAsString(); });
+
     if (const auto *Method = dyn_cast<CXXMethodDecl>(D)) {
       // Make sure to emit the definition(s) before we emit the thunks.
       // This is necessary for the generation of certain thunks.