[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

9 files changed, 67 insertions, 34 deletions

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 87165fe13a4..ba2941e9df4 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1241,7 +1241,7 @@ CodeGenFunction::GenerateBlockFunction(GlobalDecl GD,
   if (IsLambdaConversionToBlock)
     EmitLambdaBlockInvokeBody();
   else {
-    PGO.assignRegionCounters(blockDecl, fn);
+    PGO.assignRegionCounters(GlobalDecl(blockDecl), fn);
     incrementProfileCounter(blockDecl->getBody());
     EmitStmt(blockDecl->getBody());
   }
diff --git a/clang/lib/CodeGen/CGObjC.cpp b/clang/lib/CodeGen/CGObjC.cpp
index 6865f974fc2..2d5991b71fc 100644
--- a/clang/lib/CodeGen/CGObjC.cpp
+++ b/clang/lib/CodeGen/CGObjC.cpp
@@ -557,7 +557,7 @@ static llvm::Value *emitARCRetainLoadOfScalar(CodeGenFunction &CGF,
 /// its pointer, name, and types registered in the class struture.
 void CodeGenFunction::GenerateObjCMethod(const ObjCMethodDecl *OMD) {
   StartObjCMethod(OMD, OMD->getClassInterface());
-  PGO.assignRegionCounters(OMD, CurFn);
+  PGO.assignRegionCounters(GlobalDecl(OMD), CurFn);
   assert(isa<CompoundStmt>(OMD->getBody()));
   incrementProfileCounter(OMD->getBody());
   EmitCompoundStmtWithoutScope(*cast<CompoundStmt>(OMD->getBody()));
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 5ebcdf654ab..1cbdeffd7c4 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -2170,7 +2170,7 @@ CodeGenFunction::GenerateCapturedStmtFunction(const CapturedStmt &S) {
     CXXThisValue = EmitLoadOfLValue(ThisLValue, Loc).getScalarVal();
   }
 
-  PGO.assignRegionCounters(CD, F);
+  PGO.assignRegionCounters(GlobalDecl(CD), F);
   CapturedStmtInfo->EmitBody(*this, CD->getBody());
   FinishFunction(CD->getBodyRBrace());
 
diff --git a/clang/lib/CodeGen/CGStmtOpenMP.cpp b/clang/lib/CodeGen/CGStmtOpenMP.cpp
index a6099cabb59..d86cdc7110e 100644
--- a/clang/lib/CodeGen/CGStmtOpenMP.cpp
+++ b/clang/lib/CodeGen/CGStmtOpenMP.cpp
@@ -185,7 +185,7 @@ CodeGenFunction::GenerateOpenMPCapturedStmtFunction(const CapturedStmt &S) {
     ++Cnt, ++I;
   }
 
-  PGO.assignRegionCounters(CD, F);
+  PGO.assignRegionCounters(GlobalDecl(CD), F);
   CapturedStmtInfo->EmitBody(*this, CD->getBody());
   FinishFunction(CD->getBodyRBrace());
 
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 31a93e001f8..048a04328fc 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -957,8 +957,7 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
   StartFunction(GD, ResTy, Fn, FnInfo, Args, Loc, BodyRange.getBegin());
 
   // Generate the body of the function.
-  PGO.checkGlobalDecl(GD);
-  PGO.assignRegionCounters(GD.getDecl(), CurFn);
+  PGO.assignRegionCounters(GD, CurFn);
   if (isa<CXXDestructorDecl>(FD))
     EmitDestructorBody(Args);
   else if (isa<CXXConstructorDecl>(FD))
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);
 
diff --git a/clang/lib/CodeGen/CodeGenPGO.h b/clang/lib/CodeGen/CodeGenPGO.h
index 350cdcce3e8..6bf29ecaa7c 100644
--- a/clang/lib/CodeGen/CodeGenPGO.h
+++ b/clang/lib/CodeGen/CodeGenPGO.h
@@ -78,13 +78,11 @@ public:
       setCurrentRegionCount(*Count);
   }
 
-  /// Check if we need to emit coverage mapping for a given declaration
-  void checkGlobalDecl(GlobalDecl GD);
   /// Assign counters to regions and configure them for PGO of a given
   /// function. Does nothing if instrumentation is not enabled and either
   /// generates global variables or associates PGO data with each of the
   /// counters depending on whether we are generating or using instrumentation.
-  void assignRegionCounters(const Decl *D, llvm::Function *Fn);
+  void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn);
   /// Emit a coverage mapping range with a counter zero
   /// for an unused declaration.
   void emitEmptyCounterMapping(const Decl *D, StringRef FuncName,
diff --git a/clang/test/Profile/cxx-structors.cpp b/clang/test/Profile/cxx-structors.cpp
new file mode 100644
index 00000000000..24c595b863e
--- /dev/null
+++ b/clang/test/Profile/cxx-structors.cpp
@@ -0,0 +1,32 @@
+// Tests for instrumentation of C++ constructors and destructors.
+//
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.11.0 -x c++ %s -o - -emit-llvm -fprofile-instr-generate | FileCheck %s
+
+struct Foo {
+  Foo() {}
+  Foo(int) {}
+  ~Foo() {}
+};
+
+struct Bar : public Foo {
+  Bar() {}
+  Bar(int x) : Foo(x) {}
+  ~Bar();
+};
+
+Foo foo;
+Foo foo2(1);
+Bar bar;
+
+// Profile data for complete constructors and destructors must absent.
+
+// CHECK-NOT: @__llvm_profile_name__ZN3FooC1Ev
+// CHECK-NOT: @__llvm_profile_name__ZN3FooC1Ei
+// CHECK-NOT: @__llvm_profile_name__ZN3FooD1Ev
+// CHECK-NOT: @__llvm_profile_name__ZN3BarC1Ev
+// CHECK-NOT: @__llvm_profile_name__ZN3BarD1Ev
+// CHECK-NOT: @__llvm_profile_counters__ZN3FooD1Ev
+// CHECK-NOT: @__llvm_profile_data__ZN3FooD1Ev
+
+int main() {
+}
diff --git a/clang/test/Profile/cxx-virtual-destructor-calls.cpp b/clang/test/Profile/cxx-virtual-destructor-calls.cpp
index 35975c28533..d117c211437 100644
--- a/clang/test/Profile/cxx-virtual-destructor-calls.cpp
+++ b/clang/test/Profile/cxx-virtual-destructor-calls.cpp
@@ -13,18 +13,25 @@ struct B : A {
   virtual ~B();
 };
 
-// Complete dtor
-// CHECK: @__llvm_profile_name__ZN1BD1Ev = private constant [9 x i8] c"_ZN1BD1Ev"
+// Base dtor
+// CHECK: @__llvm_profile_name__ZN1BD2Ev = private constant [9 x i8] c"_ZN1BD2Ev"
 
-// Deleting dtor
-// CHECK: @__llvm_profile_name__ZN1BD0Ev = private constant [9 x i8] c"_ZN1BD0Ev"
+// Complete dtor must not be instrumented
+// CHECK-NOT: @__llvm_profile_name__ZN1BD1Ev = private constant [9 x i8] c"_ZN1BD1Ev"
 
-// Complete dtor counters and profile data
-// CHECK: @__llvm_profile_counters__ZN1BD1Ev = private global [1 x i64] zeroinitializer
-// CHECK: @__llvm_profile_data__ZN1BD1Ev =
+// Deleting dtor must not be instrumented
+// CHECK-NOT: @__llvm_profile_name__ZN1BD0Ev = private constant [9 x i8] c"_ZN1BD0Ev"
 
-// Deleting dtor counters and profile data
-// CHECK: @__llvm_profile_counters__ZN1BD0Ev = private global [1 x i64] zeroinitializer
-// CHECK: @__llvm_profile_data__ZN1BD0Ev =
+// Base dtor counters and profile data
+// CHECK: @__llvm_profile_counters__ZN1BD2Ev = private global [1 x i64] zeroinitializer
+// CHECK: @__llvm_profile_data__ZN1BD2Ev =
+
+// Complete dtor counters and profile data must absent
+// CHECK-NOT: @__llvm_profile_counters__ZN1BD1Ev = private global [1 x i64] zeroinitializer
+// CHECK-NOT: @__llvm_profile_data__ZN1BD1Ev =
+
+// Deleting dtor counters and profile data must absent
+// CHECK-NOT: @__llvm_profile_counters__ZN1BD0Ev = private global [1 x i64] zeroinitializer
+// CHECK-NOT: @__llvm_profile_data__ZN1BD0Ev =
 
 B::~B() { }