Cherry-pick from upstream: [CodeGen] Add public function to get the implicit C++ destructor argument (if existent).

clang/include/clang/CodeGen/CodeGenABITypes.h

@@ -25,7 +25,9 @@
 
 #include "clang/AST/CanonicalType.h"
 #include "clang/AST/Type.h"
+#include "clang/Basic/ABI.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
+#include "llvm/IR/BasicBlock.h"
 
 namespace llvm {
   class AttrBuilder;
@@ -40,6 +42,7 @@ namespace llvm {
 namespace clang {
 class ASTContext;
 class CXXConstructorDecl;
+class CXXDestructorDecl;
 class CXXRecordDecl;
 class CXXMethodDecl;
 class CodeGenOptions;
@@ -90,6 +93,12 @@ const CGFunctionInfo &arrangeFreeFunctionCall(CodeGenModule &CGM,
 ImplicitCXXConstructorArgs
 getImplicitCXXConstructorArgs(CodeGenModule &CGM, const CXXConstructorDecl *D);
 
+llvm::Value *
+getCXXDestructorImplicitParam(CodeGenModule &CGM, llvm::BasicBlock *InsertBlock,
+                              llvm::BasicBlock::iterator InsertPoint,
+                              const CXXDestructorDecl *D, CXXDtorType Type,
+                              bool ForVirtualBase, bool Delegating);
+
 /// Returns null if the function type is incomplete and can't be lowered.
 llvm::FunctionType *convertFreeFunctionType(CodeGenModule &CGM,
                                             const FunctionDecl *FD);

clang/lib/CodeGen/ABIInfo.h

@@ -28,7 +28,6 @@ namespace clang {
 
 namespace CodeGen {
   class ABIArgInfo;
-  class Address;
   class CGCXXABI;
   class CGFunctionInfo;
   class CodeGenFunction;

clang/lib/CodeGen/CGCXXABI.h

@@ -400,6 +400,13 @@ class CGCXXABI {
                              CXXCtorType Type, bool ForVirtualBase,
                              bool Delegating, CallArgList &Args);
 
+  /// Get the implicit (second) parameter that comes after the "this" pointer,
+  /// or nullptr if there is isn't one.
+  virtual llvm::Value *
+  getCXXDestructorImplicitParam(CodeGenFunction &CGF,
+                                const CXXDestructorDecl *DD, CXXDtorType Type,
+                                bool ForVirtualBase, bool Delegating) = 0;
+
   /// Emit the destructor call.
   virtual void EmitDestructorCall(CodeGenFunction &CGF,
                                   const CXXDestructorDecl *DD, CXXDtorType Type,

clang/lib/CodeGen/CodeGenABITypes.cpp

@@ -115,3 +115,16 @@ unsigned CodeGen::getLLVMFieldNumber(CodeGenModule &CGM,
                                      const FieldDecl *FD) {
   return CGM.getTypes().getCGRecordLayout(RD).getLLVMFieldNo(FD);
 }
+
+llvm::Value *CodeGen::getCXXDestructorImplicitParam(
+    CodeGenModule &CGM, llvm::BasicBlock *InsertBlock,
+    llvm::BasicBlock::iterator InsertPoint, const CXXDestructorDecl *D,
+    CXXDtorType Type, bool ForVirtualBase, bool Delegating) {
+  CodeGenFunction CGF(CGM, /*suppressNewContext=*/true);
+  CGF.CurCodeDecl = D;
+  CGF.CurFuncDecl = D;
+  CGF.CurFn = InsertBlock->getParent();
+  CGF.Builder.SetInsertPoint(InsertBlock, InsertPoint);
+  return CGM.getCXXABI().getCXXDestructorImplicitParam(
+      CGF, D, Type, ForVirtualBase, Delegating);
+}

clang/lib/CodeGen/ItaniumCXXABI.cpp

@@ -229,6 +229,12 @@ class ItaniumCXXABI : public CodeGen::CGCXXABI {
                                                bool ForVirtualBase,
                                                bool Delegating) override;
 
+  llvm::Value *getCXXDestructorImplicitParam(CodeGenFunction &CGF,
+                                             const CXXDestructorDecl *DD,
+                                             CXXDtorType Type,
+                                             bool ForVirtualBase,
+                                             bool Delegating) override;
+
   void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
                           CXXDtorType Type, bool ForVirtualBase,
                           bool Delegating, Address This,
@@ -1717,13 +1723,21 @@ CGCXXABI::AddedStructorArgs ItaniumCXXABI::getImplicitConstructorArgs(
   return AddedStructorArgs::prefix({{VTT, VTTTy}});
 }
 
+llvm::Value *ItaniumCXXABI::getCXXDestructorImplicitParam(
+    CodeGenFunction &CGF, const CXXDestructorDecl *DD, CXXDtorType Type,
+    bool ForVirtualBase, bool Delegating) {
+  GlobalDecl GD(DD, Type);
+  return CGF.GetVTTParameter(GD, ForVirtualBase, Delegating);
+}
+
 void ItaniumCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
                                        const CXXDestructorDecl *DD,
                                        CXXDtorType Type, bool ForVirtualBase,
                                        bool Delegating, Address This,
                                        QualType ThisTy) {
   GlobalDecl GD(DD, Type);
-  llvm::Value *VTT = CGF.GetVTTParameter(GD, ForVirtualBase, Delegating);
+  llvm::Value *VTT =
+      getCXXDestructorImplicitParam(CGF, DD, Type, ForVirtualBase, Delegating);
   QualType VTTTy = getContext().getPointerType(getContext().VoidPtrTy);
 
   CGCallee Callee;

clang/lib/CodeGen/MicrosoftCXXABI.cpp

@@ -259,6 +259,12 @@ class MicrosoftCXXABI : public CGCXXABI {
                                                bool ForVirtualBase,
                                                bool Delegating) override;
 
+  llvm::Value *getCXXDestructorImplicitParam(CodeGenFunction &CGF,
+                                             const CXXDestructorDecl *DD,
+                                             CXXDtorType Type,
+                                             bool ForVirtualBase,
+                                             bool Delegating) override;
+
   void EmitDestructorCall(CodeGenFunction &CGF, const CXXDestructorDecl *DD,
                           CXXDtorType Type, bool ForVirtualBase,
                           bool Delegating, Address This,
@@ -1577,6 +1583,12 @@ CGCXXABI::AddedStructorArgs MicrosoftCXXABI::getImplicitConstructorArgs(
   return AddedStructorArgs::suffix({{MostDerivedArg, getContext().IntTy}});
 }
 
+llvm::Value *MicrosoftCXXABI::getCXXDestructorImplicitParam(
+    CodeGenFunction &CGF, const CXXDestructorDecl *DD, CXXDtorType Type,
+    bool ForVirtualBase, bool Delegating) {
+  return nullptr;
+}
+
 void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
                                          const CXXDestructorDecl *DD,
                                          CXXDtorType Type, bool ForVirtualBase,
@@ -1603,8 +1615,11 @@ void MicrosoftCXXABI::EmitDestructorCall(CodeGenFunction &CGF,
     BaseDtorEndBB = EmitDtorCompleteObjectHandler(CGF);
   }
 
+  llvm::Value *Implicit =
+      getCXXDestructorImplicitParam(CGF, DD, Type, ForVirtualBase,
+                                    Delegating); // = nullptr
   CGF.EmitCXXDestructorCall(GD, Callee, This.getPointer(), ThisTy,
-                            /*ImplicitParam=*/nullptr,
+                            /*ImplicitParam=*/Implicit,
                             /*ImplicitParamTy=*/QualType(), nullptr);
   if (BaseDtorEndBB) {
     // Complete object handler should continue to be the remaining