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

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@357340 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index fe9fa1059a..de481e8879 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -24,6 +24,7 @@
 #include "clang/Sema/ParsedTemplate.h"
 #include "clang/Sema/Scope.h"
 #include "llvm/ADT/SmallString.h"
+#include "llvm/Support/TimeProfiler.h"
 
 using namespace clang;
 
@@ -3114,6 +3115,12 @@ void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
          TagType == DeclSpec::TST_union  ||
          TagType == DeclSpec::TST_class) && "Invalid TagType!");
 
+  llvm::TimeTraceScope TimeScope("ParseClass", [&]() {
+    if (auto *TD = dyn_cast_or_null<NamedDecl>(TagDecl))
+      return TD->getQualifiedNameAsString();
+    return std::string("<anonymous>");
+  });
+
   PrettyDeclStackTraceEntry CrashInfo(Actions.Context, TagDecl, RecordLoc,
                                       "parsing struct/union/class body");