Revert the ctor/dtor alias optimization for now; the buildbots can detect

some failure here that I can't.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@96612 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGCXX.cpp

@@ -26,88 +26,17 @@
 using namespace clang;
 using namespace CodeGen;
 
-/// Try to emit a definition as a global alias for another definition.
-bool CodeGenModule::TryEmitDefinitionAsAlias(GlobalDecl AliasDecl,
-                                             GlobalDecl TargetDecl) {
-  // Find the referrent.
-  llvm::GlobalValue *Ref = cast<llvm::GlobalValue>(GetAddrOfGlobal(TargetDecl));
-
-  // Look for an existing entry.
-  const char *MangledName = getMangledName(AliasDecl);
-  llvm::GlobalValue *&Entry = GlobalDeclMap[MangledName];
-  if (Entry) {
-    assert(Entry->isDeclaration() && "definition already exists for alias");
-    assert(Entry->getType() == Ref->getType() &&
-           "declaration exists with different type");
-  }
-
-  // The alias will use the linkage of the referrent.  If we can't
-  // support aliases with that linkage, fail.
-  llvm::GlobalValue::LinkageTypes Linkage
-    = getFunctionLinkage(cast<FunctionDecl>(AliasDecl.getDecl()));
-
-  switch (Linkage) {
-  // We can definitely emit aliases to definitions with external linkage.
-  case llvm::GlobalValue::ExternalLinkage:
-  case llvm::GlobalValue::ExternalWeakLinkage:
-    break;
-
-  // Same with local linkage.
-  case llvm::GlobalValue::InternalLinkage:
-  case llvm::GlobalValue::PrivateLinkage:
-  case llvm::GlobalValue::LinkerPrivateLinkage:
-    break;
-
-  // We should try to support linkonce linkages.
-  case llvm::GlobalValue::LinkOnceAnyLinkage:
-  case llvm::GlobalValue::LinkOnceODRLinkage:
-    return true;
-
-  // Other linkages will probably never be supported.
-  default:
-    return true;
-  }
-
-  // Create the alias with no name.
-  llvm::GlobalAlias *Alias = 
-    new llvm::GlobalAlias(Ref->getType(), Linkage, "", Ref, &getModule());
-
-  // Switch any previous uses to the alias and continue.
-  if (Entry) {
-    Entry->replaceAllUsesWith(Alias);
-    Entry->eraseFromParent();
-  }
-  Entry = Alias;
-
-  // Finally, set up the alias with its proper name and attributes.
-  Alias->setName(MangledName);
-  SetCommonAttributes(AliasDecl.getDecl(), Alias);
-
-  return false;
-}
 
 
 void CodeGenModule::EmitCXXConstructors(const CXXConstructorDecl *D) {
-  // The constructor used for constructing this as a base class;
-  // ignores virtual bases.
-  EmitGlobal(GlobalDecl(D, Ctor_Base));
-
-  // The constructor used for constructing this as a complete class;
-  // constucts the virtual bases, then calls the base constructor.
   EmitGlobal(GlobalDecl(D, Ctor_Complete));
+  EmitGlobal(GlobalDecl(D, Ctor_Base));
 }
 
 void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
                                        CXXCtorType Type) {
-  // The complete constructor is equivalent to the base constructor
-  // for classes with no virtual bases.  Try to emit it as an alias.
-  if (Type == Ctor_Complete &&
-      !D->getParent()->getNumVBases() &&
-      !TryEmitDefinitionAsAlias(GlobalDecl(D, Ctor_Complete),
-                                GlobalDecl(D, Ctor_Base)))
-    return;
 
-  llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXConstructor(D, Type));
+  llvm::Function *Fn = GetAddrOfCXXConstructor(D, Type);
 
   CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
 
@@ -115,17 +44,15 @@ void CodeGenModule::EmitCXXConstructor(const CXXConstructorDecl *D,
   SetLLVMFunctionAttributesForDefinition(D, Fn);
 }
 
-llvm::GlobalValue *
+llvm::Function *
 CodeGenModule::GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
                                        CXXCtorType Type) {
-  const char *Name = getMangledCXXCtorName(D, Type);
-  if (llvm::GlobalValue *V = GlobalDeclMap[Name])
-    return V;
-
   const FunctionProtoType *FPT = D->getType()->getAs<FunctionProtoType>();
   const llvm::FunctionType *FTy =
     getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), 
                                FPT->isVariadic());
+
+  const char *Name = getMangledCXXCtorName(D, Type);
   return cast<llvm::Function>(
                       GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
 }
@@ -140,32 +67,15 @@ const char *CodeGenModule::getMangledCXXCtorName(const CXXConstructorDecl *D,
 }
 
 void CodeGenModule::EmitCXXDestructors(const CXXDestructorDecl *D) {
-  // The destructor used for destructing this as a base class; ignores
-  // virtual bases.
-  EmitGlobal(GlobalDecl(D, Dtor_Base));
-
-  // The destructor used for destructing this as a most-derived class;
-  // call the base destructor and then destructs any virtual bases.
-  EmitGlobal(GlobalDecl(D, Dtor_Complete));
-
-  // The destructor in a virtual table is always a 'deleting'
-  // destructor, which calls the complete destructor and then uses the
-  // appropriate operator delete.
   if (D->isVirtual())
     EmitGlobal(GlobalDecl(D, Dtor_Deleting));
+  EmitGlobal(GlobalDecl(D, Dtor_Complete));
+  EmitGlobal(GlobalDecl(D, Dtor_Base));
 }
 
 void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
                                       CXXDtorType Type) {
-  // The complete destructor is equivalent to the base destructor for
+  llvm::Function *Fn = GetAddrOfCXXDestructor(D, Type);
-  // classes with no virtual bases, so try to emit it as an alias.
-  if (Type == Dtor_Complete &&
-      !D->getParent()->getNumVBases() &&
-      !TryEmitDefinitionAsAlias(GlobalDecl(D, Dtor_Complete),
-                                GlobalDecl(D, Dtor_Base)))
-    return;
-
-  llvm::Function *Fn = cast<llvm::Function>(GetAddrOfCXXDestructor(D, Type));
 
   CodeGenFunction(*this).GenerateCode(GlobalDecl(D, Type), Fn);
 
@@ -173,16 +83,13 @@ void CodeGenModule::EmitCXXDestructor(const CXXDestructorDecl *D,
   SetLLVMFunctionAttributesForDefinition(D, Fn);
 }
 
-llvm::GlobalValue *
+llvm::Function *
 CodeGenModule::GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
                                       CXXDtorType Type) {
-  const char *Name = getMangledCXXDtorName(D, Type);
-  if (llvm::GlobalValue *V = GlobalDeclMap[Name])
-    return V;
-
   const llvm::FunctionType *FTy =
     getTypes().GetFunctionType(getTypes().getFunctionInfo(D, Type), false);
 
+  const char *Name = getMangledCXXDtorName(D, Type);
   return cast<llvm::Function>(
                       GetOrCreateLLVMFunction(Name, FTy, GlobalDecl(D, Type)));
 }

lib/CodeGen/CodeGenModule.cpp

@@ -316,20 +316,24 @@ GetLinkageForFunction(ASTContext &Context, const FunctionDecl *FD,
   return CodeGenModule::GVA_CXXInline;
 }
 
-llvm::GlobalValue::LinkageTypes
+/// SetFunctionDefinitionAttributes - Set attributes for a global.
-CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
+///
+/// FIXME: This is currently only done for aliases and functions, but not for
+/// variables (these details are set in EmitGlobalVarDefinition for variables).
+void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
+                                                    llvm::GlobalValue *GV) {
   GVALinkage Linkage = GetLinkageForFunction(getContext(), D, Features);
 
   if (Linkage == GVA_Internal) {
-    return llvm::Function::InternalLinkage;
+    GV->setLinkage(llvm::Function::InternalLinkage);
   } else if (D->hasAttr<DLLExportAttr>()) {
-    return llvm::Function::DLLExportLinkage;
+    GV->setLinkage(llvm::Function::DLLExportLinkage);
   } else if (D->hasAttr<WeakAttr>()) {
-    return llvm::Function::WeakAnyLinkage;
+    GV->setLinkage(llvm::Function::WeakAnyLinkage);
   } else if (Linkage == GVA_C99Inline) {
     // In C99 mode, 'inline' functions are guaranteed to have a strong
     // definition somewhere else, so we can use available_externally linkage.
-    return llvm::Function::AvailableExternallyLinkage;
+    GV->setLinkage(llvm::Function::AvailableExternallyLinkage);
   } else if (Linkage == GVA_CXXInline || Linkage == GVA_TemplateInstantiation) {
     // In C++, the compiler has to emit a definition in every translation unit
     // that references the function.  We should use linkonce_odr because
@@ -337,22 +341,13 @@ CodeGenModule::getFunctionLinkage(const FunctionDecl *D) {
     // don't need to codegen it.  b) if the function persists, it needs to be
     // merged with other definitions. c) C++ has the ODR, so we know the
     // definition is dependable.
-    return llvm::Function::LinkOnceODRLinkage;
+    GV->setLinkage(llvm::Function::LinkOnceODRLinkage);
   } else {
     assert(Linkage == GVA_StrongExternal);
     // Otherwise, we have strong external linkage.
-    return llvm::Function::ExternalLinkage;
+    GV->setLinkage(llvm::Function::ExternalLinkage);
   }
-}
 
-
-/// SetFunctionDefinitionAttributes - Set attributes for a global.
-///
-/// FIXME: This is currently only done for aliases and functions, but not for
-/// variables (these details are set in EmitGlobalVarDefinition for variables).
-void CodeGenModule::SetFunctionDefinitionAttributes(const FunctionDecl *D,
-                                                    llvm::GlobalValue *GV) {
-  GV->setLinkage(getFunctionLinkage(D));
   SetCommonAttributes(D, GV);
 }
 

lib/CodeGen/CodeGenModule.h

@@ -206,19 +206,6 @@ public:
   /// GlobalValue.
   void setGlobalVisibility(llvm::GlobalValue *GV, const Decl *D) const;
 
-  llvm::Constant *GetAddrOfGlobal(GlobalDecl GD) {
-    if (isa<CXXConstructorDecl>(GD.getDecl()))
-      return GetAddrOfCXXConstructor(cast<CXXConstructorDecl>(GD.getDecl()),
-                                     GD.getCtorType());
-    else if (isa<CXXDestructorDecl>(GD.getDecl()))
-      return GetAddrOfCXXDestructor(cast<CXXDestructorDecl>(GD.getDecl()),
-                                     GD.getDtorType());
-    else if (isa<FunctionDecl>(GD.getDecl()))
-      return GetAddrOfFunction(GD);
-    else
-      return GetAddrOfGlobalVar(cast<VarDecl>(GD.getDecl()));
-  }
-
   /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
   /// given global variable.  If Ty is non-null and if the global doesn't exist,
   /// then it will be greated with the specified type instead of whatever the
@@ -304,13 +291,13 @@ public:
 
   /// GetAddrOfCXXConstructor - Return the address of the constructor of the
   /// given type.
-  llvm::GlobalValue *GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
+  llvm::Function *GetAddrOfCXXConstructor(const CXXConstructorDecl *D,
-                                             CXXCtorType Type);
+                                          CXXCtorType Type);
 
   /// GetAddrOfCXXDestructor - Return the address of the constructor of the
   /// given type.
-  llvm::GlobalValue *GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
+  llvm::Function *GetAddrOfCXXDestructor(const CXXDestructorDecl *D,
-                                            CXXDtorType Type);
+                                         CXXDtorType Type);
 
   /// getBuiltinLibFunction - Given a builtin id for a function like
   /// "__builtin_fabsf", return a Function* for "fabsf".
@@ -430,9 +417,6 @@ public:
     GVA_TemplateInstantiation
   };
 
-  llvm::GlobalVariable::LinkageTypes
-  getFunctionLinkage(const FunctionDecl *FD);
-
   /// getVtableLinkage - Return the appropriate linkage for the vtable, VTT,
   /// and type information of the given class.
   static llvm::GlobalVariable::LinkageTypes 
@@ -484,8 +468,6 @@ private:
 
   // C++ related functions.
 
-  bool TryEmitDefinitionAsAlias(GlobalDecl Alias, GlobalDecl Target);
-
   void EmitNamespace(const NamespaceDecl *D);
   void EmitLinkageSpec(const LinkageSpecDecl *D);
 

test/CodeGenCXX/default-arguments.cpp

@@ -26,8 +26,6 @@ struct B {
  B(const A1& = A1(), const A2& = A2());
 };
 
-// CHECK: @_ZN1CC1Ev = alias {{.*}} @_ZN1CC2Ev
-
 // CHECK: define void @_Z2f1v()
 void f1() {
 
@@ -44,6 +42,13 @@ struct C {
  C();
 };
 
+// CHECK: define void @_ZN1CC1Ev(
+// CHECK: call void @_ZN2A1C1Ev(
+// CHECK: call void @_ZN2A2C1Ev(
+// CHECK: call void @_ZN1BC1ERK2A1RK2A2(
+// CHECK: call void @_ZN2A2D1Ev
+// CHECK: call void @_ZN2A1D1Ev
+
 // CHECK: define void @_ZN1CC2Ev(
 // CHECK: call void @_ZN2A1C1Ev(
 // CHECK: call void @_ZN2A2C1Ev(

test/CodeGenCXX/mangle-subst-std.cpp

@@ -1,10 +1,9 @@
 // RUN: %clang_cc1 -emit-llvm %s -o - -triple=x86_64-apple-darwin9 | FileCheck %s
 
-// CHECK: @_ZNSt1AC1Ev = alias {{.*}} @_ZNSt1AC2Ev
-
 namespace std {
   struct A { A(); };
   
+  // CHECK: define void @_ZNSt1AC1Ev
   // CHECK: define void @_ZNSt1AC2Ev
   A::A() { }
 };

test/CodeGenCXX/mangle.cpp

@@ -11,8 +11,6 @@ struct Y { };
 //CHECK: @pr5966_i = external global
 //CHECK: @_ZL8pr5966_i = internal global
 
-// CHECK: @_ZN2S7C1Ev = alias {{.*}} @_ZN2S7C2Ev
-
 // CHECK: define zeroext i1 @_ZplRK1YRA100_P1X
 bool operator+(const Y&, X* (&xs)[100]) { return false; }
 
@@ -221,6 +219,7 @@ struct S7 {
 };
 
 // PR5139
+// CHECK: @_ZN2S7C1Ev
 // CHECK: @_ZN2S7C2Ev
 // CHECK: @"_ZN2S73$_0C1Ev"
 S7::S7() {}

test/CodeGenCXX/member-templates.cpp

@@ -15,7 +15,7 @@ struct B {
 
 template<typename T> B::B(T) {}
 
-// CHECK: @_ZN1BC1IiEET_ = alias {{.*}} @_ZN1BC2IiEET_
+// CHECK: define void @_ZN1BC1IiEET_(%struct.B* %this, i32)
 // CHECK: define void @_ZN1BC2IiEET_(%struct.B* %this, i32)
 template B::B(int);
 

test/CodeGenCXX/virtual-bases.cpp

@@ -4,7 +4,7 @@ struct A {
   A();
 };
 
-// CHECK: @_ZN1AC1Ev = alias {{.*}} @_ZN1AC2Ev
+// CHECK: define void @_ZN1AC1Ev(%struct.A* %this)
 // CHECK: define void @_ZN1AC2Ev(%struct.A* %this)
 A::A() { }
 
@@ -12,14 +12,14 @@ struct B : virtual A {
   B();
 };
 
-// CHECK: define void @_ZN1BC2Ev(%struct.B* %this, i8** %vtt)
 // CHECK: define void @_ZN1BC1Ev(%struct.B* %this)
+// CHECK: define void @_ZN1BC2Ev(%struct.B* %this, i8** %vtt)
 B::B() { }
 
 struct C : virtual A {
   C(bool);
 };
 
-// CHECK: define void @_ZN1CC2Eb(%struct.B* %this, i8** %vtt, i1 zeroext)
 // CHECK: define void @_ZN1CC1Eb(%struct.B* %this, i1 zeroext)
+// CHECK: define void @_ZN1CC2Eb(%struct.B* %this, i8** %vtt, i1 zeroext)
 C::C(bool) { }

test/CodeGenCXX/virtual-destructor-calls.cpp

@@ -8,8 +8,9 @@ struct B : A {
   virtual ~B();
 };
 
-// Complete dtor: just an alias because there are no virtual bases.
+// Complete dtor: just defers to base dtor because there are no vbases.
-// CHECK: @_ZN1BD1Ev = alias {{.*}} @_ZN1BD2Ev
+// CHECK: define void @_ZN1BD1Ev
+// CHECK: call void @_ZN1BD2Ev
 
 // Deleting dtor: defers to the complete dtor.
 // CHECK: define void @_ZN1BD0Ev

test/CodeGenCXX/vtable-pointer-initialization.cpp

@@ -19,14 +19,14 @@ struct A : Base {
   Field field;
 };
 
-// CHECK: define void @_ZN1AC2Ev(
+// CHECK: define void @_ZN1AC1Ev(
 // CHECK: call void @_ZN4BaseC2Ev(
 // CHECK: store i8** getelementptr inbounds ([3 x i8*]* @_ZTV1A, i64 0, i64 2)
 // CHECK: call void @_ZN5FieldC1Ev(
 // CHECK: ret void
 A::A() { }
 
-// CHECK: define void @_ZN1AD2Ev(
+// CHECK: define void @_ZN1AD1Ev(
 // CHECK: store i8** getelementptr inbounds ([3 x i8*]* @_ZTV1A, i64 0, i64 2)
 // CHECK: call void @_ZN5FieldD1Ev(
 // CHECK: call void @_ZN4BaseD2Ev(