[CodeGen] Handle recursion in LLVMIRGeneration Timer.

This can happen when emitting a local decl, which triggers
loading a decl imported from an AST file, which we then
hand to the AST consumer. Timer is not allowed to recurse
so an assertion fire. Keep a reference counter to avoid this
problem. LGTM'd by Richard Smith on IRC.

Differential Revision:  https://reviews.llvm.org/D20748

llvm-svn: 276242

1 files changed, 23 insertions, 8 deletions

diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index 747899cfac9..dd803909f03 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -49,6 +49,7 @@ namespace clang {
     ASTContext *Context;
 
     Timer LLVMIRGeneration;
+    unsigned LLVMIRGenerationRefCount;
 
     std::unique_ptr<CodeGenerator> Gen;
 
@@ -73,6 +74,7 @@ namespace clang {
           TargetOpts(TargetOpts), LangOpts(LangOpts),
           AsmOutStream(std::move(OS)), Context(nullptr),
           LLVMIRGeneration("LLVM IR Generation Time"),
+          LLVMIRGenerationRefCount(0),
           Gen(CreateLLVMCodeGen(Diags, InFile, HeaderSearchOpts, PPOpts,
                                 CodeGenOpts, C, CoverageInfo)) {
       llvm::TimePassesIsEnabled = TimePasses;
@@ -112,13 +114,20 @@ namespace clang {
                                      Context->getSourceManager(),
                                      "LLVM IR generation of declaration");
 
-      if (llvm::TimePassesIsEnabled)
-        LLVMIRGeneration.startTimer();
+      // Recurse.
+      if (llvm::TimePassesIsEnabled) {
+        LLVMIRGenerationRefCount += 1;
+        if (LLVMIRGenerationRefCount == 1)
+          LLVMIRGeneration.startTimer();
+      }
 
       Gen->HandleTopLevelDecl(D);
 
-      if (llvm::TimePassesIsEnabled)
-        LLVMIRGeneration.stopTimer();
+      if (llvm::TimePassesIsEnabled) {
+        LLVMIRGenerationRefCount -= 1;
+        if (LLVMIRGenerationRefCount == 0)
+          LLVMIRGeneration.stopTimer();
+      }
 
       return true;
     }
@@ -139,13 +148,19 @@ namespace clang {
     void HandleTranslationUnit(ASTContext &C) override {
       {
         PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
-        if (llvm::TimePassesIsEnabled)
-          LLVMIRGeneration.startTimer();
+        if (llvm::TimePassesIsEnabled) {
+          LLVMIRGenerationRefCount += 1;
+          if (LLVMIRGenerationRefCount == 1)
+            LLVMIRGeneration.startTimer();
+        }
 
         Gen->HandleTranslationUnit(C);
 
-        if (llvm::TimePassesIsEnabled)
-          LLVMIRGeneration.stopTimer();
+        if (llvm::TimePassesIsEnabled) {
+          LLVMIRGenerationRefCount -= 1;
+          if (LLVMIRGenerationRefCount == 0)
+            LLVMIRGeneration.stopTimer();
+        }
       }
 
       // Silently ignore if we weren't initialized for some reason.