From: Justin Bogner <mail@justinbogner.com>
Date: Mon, 13 Jan 2014 21:24:18 +0000 (+0000)
Subject: CodeGen: Introduce CodeGenPGO::setCurrentRegionUnreachable
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d1361b32e7934a5cfaffffa2bad75c25bba08e88;p=clang

CodeGen: Introduce CodeGenPGO::setCurrentRegionUnreachable

There are a number of places where we do PGO.setCurrentRegionCount(0)
directly after an unconditional branch. Give this operation a name so
that it's clearer why we're doing this.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@199138 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 4bdd032a2b..d312177446 100644
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -2184,7 +2184,7 @@ void CodeGenFunction::EmitNoreturnRuntimeCallOrInvoke(llvm::Value *callee,
     call->setCallingConv(getRuntimeCC());
     Builder.CreateUnreachable();
   }
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 /// Emits a call or invoke instruction to the given nullary runtime
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index ade6ac9185..a9c691ea0c 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -404,14 +404,14 @@ void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) {
     EmitStopPoint(&S);
 
   EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel()));
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 
 void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
   if (const LabelDecl *Target = S.getConstantTarget()) {
     EmitBranchThroughCleanup(getJumpDestForLabel(Target));
-    PGO.setCurrentRegionCount(0);
+    PGO.setCurrentRegionUnreachable();
     return;
   }
 
@@ -428,7 +428,7 @@ void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) {
   cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB);
 
   EmitBranch(IndGotoBB);
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 void CodeGenFunction::EmitIfStmt(const IfStmt &S) {
@@ -847,7 +847,7 @@ void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) {
                        /*init*/ true);
   }
   EmitBranchThroughCleanup(ReturnBlock);
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 /// EmitReturnStmt - Note that due to GCC extensions, this can have an operand
@@ -920,7 +920,7 @@ void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) {
 
   cleanupScope.ForceCleanup();
   EmitBranchThroughCleanup(ReturnBlock);
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) {
@@ -950,7 +950,7 @@ void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) {
   if (BC.CountBreak)
     BC.LoopCnt->getBreakCounter().beginRegion(Builder);
   EmitBranchThroughCleanup(BC.BreakBlock);
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
@@ -967,7 +967,7 @@ void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) {
   // non-local exits in PGO instrumentation.
   BC.LoopCnt->getContinueCounter().beginRegion(Builder);
   EmitBranchThroughCleanup(BC.ContinueBlock);
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 }
 
 /// EmitCaseStmtRange - If case statement range is not too big then
@@ -1438,7 +1438,7 @@ void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) {
 
   // Clear the insertion point to indicate we are in unreachable code.
   Builder.ClearInsertionPoint();
-  PGO.setCurrentRegionCount(0);
+  PGO.setCurrentRegionUnreachable();
 
   // All break statements jump to NextBlock. If BreakContinueStack is non-empty
   // then reuse last ContinueBlock and that block's counter.
diff --git a/lib/CodeGen/CodeGenPGO.h b/lib/CodeGen/CodeGenPGO.h
index 0a0699067b..a459e42d29 100644
--- a/lib/CodeGen/CodeGenPGO.h
+++ b/lib/CodeGen/CodeGenPGO.h
@@ -74,6 +74,10 @@ public:
   /// of changes to the most recent counter from control flow and non-local
   /// exits.
   void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
+  /// Indicate that the current region is never reached, and thus should have a
+  /// counter value of zero. This is important so that subsequent regions can
+  /// correctly track their parent counts.
+  void setCurrentRegionUnreachable() { setCurrentRegionCount(0); }
 
   /// Calculate branch weights appropriate for PGO data
   llvm::MDNode *createBranchWeights(uint64_t TrueCount, uint64_t FalseCount);