[PGO] Instrument only base constructors and destructors.

Constructors and destructors may be represented by several functions
in IR. Only base structors correspond to source code, others are
small pieces of code and eventually call the base variant. In this
case instrumentation of non-base structors has little sense, this
fix remove it. Now profile data of a declaration corresponds to
exactly one function in IR, it agrees with the current logic of the
profile data loading.

This change fixes PR24996.

Differential Revision: http://reviews.llvm.org/D15158

llvm-svn: 254876

1 files changed, 12 insertions, 15 deletions

diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index 403380efcb4..38774332f31 100644
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -605,27 +605,24 @@ uint64_t PGOHash::finalize() {
   return endian::read<uint64_t, little, unaligned>(Result);
 }
 
-void CodeGenPGO::checkGlobalDecl(GlobalDecl GD) {
-  // Make sure we only emit coverage mapping for one constructor/destructor.
-  // Clang emits several functions for the constructor and the destructor of
-  // a class. Every function is instrumented, but we only want to provide
-  // coverage for one of them. Because of that we only emit the coverage mapping
-  // for the base constructor/destructor.
-  if ((isa<CXXConstructorDecl>(GD.getDecl()) &&
-       GD.getCtorType() != Ctor_Base) ||
-      (isa<CXXDestructorDecl>(GD.getDecl()) &&
-       GD.getDtorType() != Dtor_Base)) {
-    SkipCoverageMapping = true;
-  }
-}
-
-void CodeGenPGO::assignRegionCounters(const Decl *D, llvm::Function *Fn) {
+void CodeGenPGO::assignRegionCounters(GlobalDecl GD, llvm::Function *Fn) {
+  const Decl *D = GD.getDecl();
   bool InstrumentRegions = CGM.getCodeGenOpts().ProfileInstrGenerate;
   llvm::IndexedInstrProfReader *PGOReader = CGM.getPGOReader();
   if (!InstrumentRegions && !PGOReader)
     return;
   if (D->isImplicit())
     return;
+  // Constructors and destructors may be represented by several functions in IR.
+  // If so, instrument only base variant, others are implemented by delegation
+  // to the base one, it would be counted twice otherwise.
+  if (CGM.getTarget().getCXXABI().hasConstructorVariants() &&
+      ((isa<CXXConstructorDecl>(GD.getDecl()) &&
+        GD.getCtorType() != Ctor_Base) ||
+       (isa<CXXDestructorDecl>(GD.getDecl()) &&
+        GD.getDtorType() != Dtor_Base))) {
+      return;
+  }
   CGM.ClearUnusedCoverageMapping(D);
   setFuncName(Fn);