revert r177211 due to its potential issues

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177222 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGCXXABI.h b/lib/CodeGen/CGCXXABI.h
index d0384ecc128250f1f40f9470a17ceda5891d2206..cdc87b70e554107cf405fb5320b0168966a432c9 100644 (file)
--- a/lib/CodeGen/CGCXXABI.h
+++ b/lib/CodeGen/CGCXXABI.h
@@ -91,10 +91,6 @@ public:
     return *MangleCtx;
   }
 
-  /// Returns true if the given instance method is one of the
-  /// kinds that the ABI says returns 'this'.
-  virtual bool HasThisReturn(GlobalDecl GD) const { return false; }
-
   /// Find the LLVM type used to represent the given member pointer
   /// type.
   virtual llvm::Type *
@@ -213,8 +209,7 @@ public:
   /// Emit the ABI-specific prolog for the function.
   virtual void EmitInstanceFunctionProlog(CodeGenFunction &CGF) = 0;
 
-  /// Emit the constructor call. Return the function that is called.
-  virtual llvm::Value *EmitConstructorCall(CodeGenFunction &CGF,
+  virtual void EmitConstructorCall(CodeGenFunction &CGF,
                                    const CXXConstructorDecl *D,
                                    CXXCtorType Type, bool ForVirtualBase,
                                    bool Delegating,

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 6438ebf846df5316a4c78222eb0bacde9f7acaf2..9e97bce6c3eafabc971070b7e7b3e102e0b00bde 100644 (file)
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -1705,18 +1705,6 @@ void CodeGenFunction::EmitFunctionEpilog(const CGFunctionInfo &FI) {
     llvm_unreachable("Invalid ABI kind for return argument");
   }
 
-  // If this function returns 'this' and the last instruction is a CallInst
-  // that returns 'this', use the return value from the CallInst. We will not
-  // need to keep 'this' alive through the callsite. It also enables
-  // optimizations in the backend, such as tail call optimization.
-  if (CalleeWithThisReturn && CGM.getCXXABI().HasThisReturn(CurGD)) {
-    llvm::BasicBlock *IP = Builder.GetInsertBlock();
-    llvm::CallInst *Callsite;
-    if (!IP->empty() && (Callsite = dyn_cast<llvm::CallInst>(&IP->back())) &&
-        Callsite->getCalledFunction() == CalleeWithThisReturn)
-      // Create a bitcast of Callsite.
-      RV = Builder.CreateBitCast(Callsite, RetAI.getCoerceToType());
-  }
   llvm::Instruction *Ret = RV ? Builder.CreateRet(RV) : Builder.CreateRetVoid();
   if (!RetDbgLoc.isUnknown())
     Ret->setDebugLoc(RetDbgLoc);

diff --git a/lib/CodeGen/CGClass.cpp b/lib/CodeGen/CGClass.cpp
index 2ececb03651ad3b47f15225bb3e2769aeadad6f8..287d164cb9924bfdfcb7d5f5fef66c604333f47e 100644 (file)
--- a/lib/CodeGen/CGClass.cpp
+++ b/lib/CodeGen/CGClass.cpp
@@ -1666,11 +1666,8 @@ CodeGenFunction::EmitCXXConstructorCall(const CXXConstructorDecl *D,
   }
 
   // Non-trivial constructors are handled in an ABI-specific manner.
-  llvm::Value *Callee = CGM.getCXXABI().EmitConstructorCall(*this, D, Type,
-                            ForVirtualBase, Delegating, This, ArgBeg, ArgEnd);
-  if (CGM.getCXXABI().HasThisReturn(CurGD) &&
-      CGM.getCXXABI().HasThisReturn(GlobalDecl(D, Type)))
-     CalleeWithThisReturn = Callee;
+  CGM.getCXXABI().EmitConstructorCall(*this, D, Type, ForVirtualBase,
+                                      Delegating, This, ArgBeg, ArgEnd);
 }
 
 void
@@ -1759,12 +1756,9 @@ CodeGenFunction::EmitDelegateCXXConstructorCall(const CXXConstructorDecl *Ctor,
     EmitDelegateCallArg(DelegateArgs, param);
   }
 
-  llvm::Value *Callee = CGM.GetAddrOfCXXConstructor(Ctor, CtorType);
   EmitCall(CGM.getTypes().arrangeCXXConstructorDeclaration(Ctor, CtorType),
-           Callee, ReturnValueSlot(), DelegateArgs, Ctor);
-  if (CGM.getCXXABI().HasThisReturn(CurGD) &&
-      CGM.getCXXABI().HasThisReturn(GlobalDecl(Ctor, CtorType)))
-     CalleeWithThisReturn = Callee;
+           CGM.GetAddrOfCXXConstructor(Ctor, CtorType), 
+           ReturnValueSlot(), DelegateArgs, Ctor);
 }
 
 namespace {
@@ -1831,9 +1825,6 @@ void CodeGenFunction::EmitCXXDestructorCall(const CXXDestructorDecl *DD,
   EmitCXXMemberCall(DD, SourceLocation(), Callee, ReturnValueSlot(), This,
                     VTT, getContext().getPointerType(getContext().VoidPtrTy),
                     0, 0);
-  if (CGM.getCXXABI().HasThisReturn(CurGD) &&
-      CGM.getCXXABI().HasThisReturn(GlobalDecl(DD, Type)))
-     CalleeWithThisReturn = Callee;
 }
 
 namespace {

diff --git a/lib/CodeGen/CodeGenFunction.cpp b/lib/CodeGen/CodeGenFunction.cpp
index 98a63464f95addabbc313720bcd0af4502db3b52..27ef65fa94b47bb598eb793fd7402cfa6025fd17 100644 (file)
--- a/lib/CodeGen/CodeGenFunction.cpp
+++ b/lib/CodeGen/CodeGenFunction.cpp
@@ -564,9 +564,6 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
   SourceRange BodyRange;
   if (Stmt *Body = FD->getBody()) BodyRange = Body->getSourceRange();
 
-  // Reset CalleeWithThisReturn.
-  CalleeWithThisReturn = 0;
-
   // Emit the standard function prologue.
   StartFunction(GD, ResTy, Fn, FnInfo, Args, BodyRange.getBegin());
 
@@ -618,8 +615,6 @@ void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
 
   // Emit the standard function epilogue.
   FinishFunction(BodyRange.getEnd());
-  // Reset CalleeWithThisReturn.
-  CalleeWithThisReturn = 0;
 
   // If we haven't marked the function nothrow through other means, do
   // a quick pass now to see if we can.

diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index 19a4d571ee2bc8ad6176e3243c9ef43e59e2bc09..55c21e80ee2659182a896f8307b55d970435d61c 100644 (file)
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -1131,10 +1131,6 @@ private:
   CGDebugInfo *DebugInfo;
   bool DisableDebugInfo;
 
-  /// If the current function returns 'this', use the field to keep track of
-  /// the callee that returns 'this'.
-  llvm::Value *CalleeWithThisReturn;
-
   /// DidCallStackSave - Whether llvm.stacksave has been called. Used to avoid
   /// calling llvm.stacksave for multiple VLAs in the same scope.
   bool DidCallStackSave;

diff --git a/lib/CodeGen/ItaniumCXXABI.cpp b/lib/CodeGen/ItaniumCXXABI.cpp
index 17e83a18b9723eaad544e0dad44acf0d2ef20a74..8c7a759a43ea226c3e40cb12665d8acd1047407c 100644 (file)
--- a/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/lib/CodeGen/ItaniumCXXABI.cpp
@@ -112,7 +112,7 @@ public:
 
   void EmitInstanceFunctionProlog(CodeGenFunction &CGF);
 
-  llvm::Value *EmitConstructorCall(CodeGenFunction &CGF,
+  void EmitConstructorCall(CodeGenFunction &CGF,
                            const CXXConstructorDecl *D,
                            CXXCtorType Type, bool ForVirtualBase,
                            bool Delegating,
@@ -177,11 +177,11 @@ public:
   llvm::Value *readArrayCookieImpl(CodeGenFunction &CGF, llvm::Value *allocPtr,
                                    CharUnits cookieSize);
 
+private:
   /// \brief Returns true if the given instance method is one of the
   /// kinds that the ARM ABI says returns 'this'.
-  bool HasThisReturn(GlobalDecl GD) const {
-    const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(GD.getDecl());
-    if (!MD) return false;
+  static bool HasThisReturn(GlobalDecl GD) {
+    const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
     return ((isa<CXXDestructorDecl>(MD) && GD.getDtorType() != Dtor_Deleting) ||
             (isa<CXXConstructorDecl>(MD)));
   }
@@ -834,7 +834,7 @@ void ARMCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
     CGF.Builder.CreateStore(getThisValue(CGF), CGF.ReturnValue);
 }
 
-llvm::Value *ItaniumCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
+void ItaniumCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
                                         const CXXConstructorDecl *D,
                                         CXXCtorType Type, bool ForVirtualBase,
                                         bool Delegating,
@@ -849,7 +849,6 @@ llvm::Value *ItaniumCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
   // FIXME: Provide a source location here.
   CGF.EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), This,
                         VTT, VTTTy, ArgBeg, ArgEnd);
-  return Callee;
 }
 
 RValue ItaniumCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF,

diff --git a/lib/CodeGen/MicrosoftCXXABI.cpp b/lib/CodeGen/MicrosoftCXXABI.cpp
index 85d926023f38a7d6eac634de11922c7b149035e0..fb6b86d87883ddded20d7fad3a17744b1f5ac718 100644 (file)
--- a/lib/CodeGen/MicrosoftCXXABI.cpp
+++ b/lib/CodeGen/MicrosoftCXXABI.cpp
@@ -55,7 +55,7 @@ public:
 
   void EmitInstanceFunctionProlog(CodeGenFunction &CGF);
 
-  llvm::Value *EmitConstructorCall(CodeGenFunction &CGF,
+  void EmitConstructorCall(CodeGenFunction &CGF,
                            const CXXConstructorDecl *D,
                            CXXCtorType Type, bool ForVirtualBase,
                            bool Delegating,
@@ -238,7 +238,7 @@ void MicrosoftCXXABI::EmitInstanceFunctionProlog(CodeGenFunction &CGF) {
   }
 }
 
-llvm::Value *MicrosoftCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
+void MicrosoftCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
                                           const CXXConstructorDecl *D,
                                           CXXCtorType Type, bool ForVirtualBase,
                                           bool Delegating,
@@ -259,7 +259,6 @@ llvm::Value *MicrosoftCXXABI::EmitConstructorCall(CodeGenFunction &CGF,
   CGF.EmitCXXMemberCall(D, SourceLocation(), Callee, ReturnValueSlot(), This,
                         ImplicitParam, ImplicitParamTy,
                         ArgBeg, ArgEnd);
-  return Callee;
 }
 
 RValue MicrosoftCXXABI::EmitVirtualDestructorCall(CodeGenFunction &CGF,

diff --git a/test/CodeGenCXX/arm.cpp b/test/CodeGenCXX/arm.cpp
index 48f2f008401568b75b1760676fddc1133df65c72..3d3b147aa1ff736951300f0c0600d90c25737a50 100644 (file)
--- a/test/CodeGenCXX/arm.cpp
+++ b/test/CodeGenCXX/arm.cpp
@@ -56,15 +56,15 @@ namespace test1 {
   // CHECK:   [[THIS:%.*]] = alloca [[A]]*, align 4
   // CHECK:   store [[A]]* {{.*}}, [[A]]** [[THIS]]
   // CHECK:   [[THIS1:%.*]] = load [[A]]** [[THIS]]
-  // CHECK:   [[THIS2:%.*]] = call [[A]]* @_ZN5test11AC2Ei(
-  // CHECK:   ret [[A]]* [[THIS2]]
+  // CHECK:   call [[A]]* @_ZN5test11AC2Ei(
+  // CHECK:   ret [[A]]* [[THIS1]]
 
   // CHECK: define linkonce_odr [[A]]* @_ZN5test11AD1Ev([[A]]* %this) unnamed_addr
   // CHECK:   [[THIS:%.*]] = alloca [[A]]*, align 4
   // CHECK:   store [[A]]* {{.*}}, [[A]]** [[THIS]]
   // CHECK:   [[THIS1:%.*]] = load [[A]]** [[THIS]]
-  // CHECK:   [[THIS2:%.*]] = call [[A]]* @_ZN5test11AD2Ev(
-  // CHECK:   ret [[A]]* [[THIS2]]
+  // CHECK:   call [[A]]* @_ZN5test11AD2Ev(
+  // CHECK:   ret [[A]]* [[THIS1]]
 }
 
 // Awkward virtual cases.