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

1 files changed, 18 insertions, 2 deletions

diff --git a/clang/lib/Sema/Sema.cpp b/clang/lib/Sema/Sema.cpp
index da87e156835..bc4fdfbe58e 100644
--- a/clang/lib/Sema/Sema.cpp
+++ b/clang/lib/Sema/Sema.cpp
@@ -39,6 +39,8 @@
 #include "clang/Sema/TemplateInstCallback.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallSet.h"
+#include "llvm/Support/TimeProfiler.h"
+
 using namespace clang;
 using namespace sema;
 
@@ -92,6 +94,12 @@ public:
       SourceManager &SM = S->getSourceManager();
       SourceLocation IncludeLoc = SM.getIncludeLoc(SM.getFileID(Loc));
       if (IncludeLoc.isValid()) {
+        if (llvm::timeTraceProfilerEnabled()) {
+          const FileEntry *FE = SM.getFileEntryForID(SM.getFileID(Loc));
+          llvm::timeTraceProfilerBegin(
+              "Source", FE != nullptr ? FE->getName() : StringRef("<unknown>"));
+        }
+
         IncludeStack.push_back(IncludeLoc);
         S->DiagnoseNonDefaultPragmaPack(
             Sema::PragmaPackDiagnoseKind::NonDefaultStateAtInclude, IncludeLoc);
@@ -99,10 +107,14 @@ public:
       break;
     }
     case ExitFile:
-      if (!IncludeStack.empty())
+      if (!IncludeStack.empty()) {
+        if (llvm::timeTraceProfilerEnabled())
+          llvm::timeTraceProfilerEnd();
+
         S->DiagnoseNonDefaultPragmaPack(
             Sema::PragmaPackDiagnoseKind::ChangedStateAtExit,
             IncludeStack.pop_back_val());
+      }
       break;
     default:
       break;
@@ -914,7 +926,11 @@ void Sema::ActOnEndOfTranslationUnit() {
                                    Pending.begin(), Pending.end());
     }
 
-    PerformPendingInstantiations();
+    {
+      llvm::TimeTraceScope TimeScope("PerformPendingInstantiations",
+                                     StringRef(""));
+      PerformPendingInstantiations();
+    }
 
     assert(LateParsedInstantiations.empty() &&
            "end of TU template instantiation should not create more "