Handle constructors and destructors a bit more uniformly in CodeGen.

There were code paths that are duplicated for constructors and destructors just
because we have both CXXCtorType and CXXDtorsTypes.

This patch introduces an unified enum and reduces code deplication a bit.

llvm-svn: 217383
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index f861af3..60b6ecd 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -138,15 +138,10 @@
                               const CXXRecordDecl *ClassDecl,
                               const CXXRecordDecl *BaseClassDecl) override;
 
-  void BuildConstructorSignature(const CXXConstructorDecl *Ctor,
-                                 CXXCtorType T, CanQualType &ResTy,
-                                 SmallVectorImpl<CanQualType> &ArgTys) override;
-
   void EmitCXXConstructors(const CXXConstructorDecl *D) override;
 
-  void BuildDestructorSignature(const CXXDestructorDecl *Dtor,
-                                CXXDtorType T, CanQualType &ResTy,
-                                SmallVectorImpl<CanQualType> &ArgTys) override;
+  void buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
+                              SmallVectorImpl<CanQualType> &ArgTys) override;
 
   bool useThunkForDtorVariant(const CXXDestructorDecl *Dtor,
                               CXXDtorType DT) const override {
@@ -1066,23 +1061,6 @@
   return VBaseOffset;
 }
 
-/// The generic ABI passes 'this', plus a VTT if it's initializing a
-/// base subobject.
-void
-ItaniumCXXABI::BuildConstructorSignature(const CXXConstructorDecl *Ctor,
-                                         CXXCtorType Type, CanQualType &ResTy,
-                                         SmallVectorImpl<CanQualType> &ArgTys) {
-  ASTContext &Context = getContext();
-
-  // All parameters are already in place except VTT, which goes after 'this'.
-  // These are Clang types, so we don't need to worry about sret yet.
-
-  // Check if we need to add a VTT parameter (which has type void **).
-  if (Type == Ctor_Base && Ctor->getParent()->getNumVBases() != 0)
-    ArgTys.insert(ArgTys.begin() + 1,
-                  Context.getPointerType(Context.VoidPtrTy));
-}
-
 void ItaniumCXXABI::EmitCXXConstructors(const CXXConstructorDecl *D) {
   // Just make sure we're in sync with TargetCXXABI.
   assert(CGM.getTarget().getCXXABI().hasConstructorVariants());
@@ -1099,20 +1077,18 @@
   }
 }
 
-/// The generic ABI passes 'this', plus a VTT if it's destroying a
-/// base subobject.
-void ItaniumCXXABI::BuildDestructorSignature(const CXXDestructorDecl *Dtor,
-                                             CXXDtorType Type,
-                                             CanQualType &ResTy,
-                                SmallVectorImpl<CanQualType> &ArgTys) {
+void
+ItaniumCXXABI::buildStructorSignature(const CXXMethodDecl *MD, StructorType T,
+                                      SmallVectorImpl<CanQualType> &ArgTys) {
   ASTContext &Context = getContext();
 
-  // 'this' parameter is already there, as well as 'this' return if
-  // HasThisReturn(GlobalDecl(Dtor, Type)) is true
+  // All parameters are already in place except VTT, which goes after 'this'.
+  // These are Clang types, so we don't need to worry about sret yet.
 
   // Check if we need to add a VTT parameter (which has type void **).
-  if (Type == Dtor_Base && Dtor->getParent()->getNumVBases() != 0)
-    ArgTys.push_back(Context.getPointerType(Context.VoidPtrTy));
+  if (T == StructorType::Base && MD->getParent()->getNumVBases() != 0)
+    ArgTys.insert(ArgTys.begin() + 1,
+                  Context.getPointerType(Context.VoidPtrTy));
 }
 
 void ItaniumCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
@@ -1346,8 +1322,8 @@
   assert(CE == nullptr || CE->arg_begin() == CE->arg_end());
   assert(DtorType == Dtor_Deleting || DtorType == Dtor_Complete);
 
-  const CGFunctionInfo *FInfo
-    = &CGM.getTypes().arrangeCXXDestructor(Dtor, DtorType);
+  const CGFunctionInfo *FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
+      Dtor, getFromDtorType(DtorType));
   llvm::Type *Ty = CGF.CGM.getTypes().GetFunctionType(*FInfo);
   llvm::Value *Callee =
       getVirtualFunctionPointer(CGF, GlobalDecl(Dtor, DtorType), This, Ty);