Fix a mangling failure on clang-cl C++17

MethodVFTableLocations in MigrosoftVTableContext contains canonicalized
decl. But, it's sometimes asked to lookup for non-canonicalized decl,
and that causes assertion failure, and compilation failure.

Fixes PR37481.

Patch by Taiju Tsuiki!

Differential Revision: https://reviews.llvm.org/D46929

llvm-svn: 332639

clang/lib/AST/VTableBuilder.cpp

@@ -2223,6 +2223,7 @@ ItaniumVTableContext::ItaniumVTableContext(ASTContext &Context)
 ItaniumVTableContext::~ItaniumVTableContext() {}
 
 uint64_t ItaniumVTableContext::getMethodVTableIndex(GlobalDecl GD) {
+  GD = GD.getCanonicalDecl();
   MethodVTableIndicesTy::iterator I = MethodVTableIndices.find(GD);
   if (I != MethodVTableIndices.end())
     return I->second;
@@ -2503,6 +2504,8 @@ class VFTableBuilder {
     for (const auto &I : MethodInfoMap) {
       const CXXMethodDecl *MD = I.first;
       const MethodInfo &MI = I.second;
+      assert(MD == MD->getCanonicalDecl());
+
       // Skip the methods that the MostDerivedClass didn't override
       // and the entries shadowed by return adjusting thunks.
       if (MD->getParent() != MostDerivedClass || MI.Shadowed)
@@ -3737,6 +3740,8 @@ MicrosoftVTableContext::getMethodVFTableLocation(GlobalDecl GD) {
   if (isa<CXXDestructorDecl>(GD.getDecl()))
     assert(GD.getDtorType() == Dtor_Deleting);
 
+  GD = GD.getCanonicalDecl();
+
   MethodVFTableLocationsTy::iterator I = MethodVFTableLocations.find(GD);
   if (I != MethodVFTableLocations.end())
     return I->second;

clang/lib/CodeGen/CGCXX.cpp

@@ -267,7 +267,6 @@ static CGCallee BuildAppleKextVirtualCall(CodeGenFunction &CGF,
                                           const CXXRecordDecl *RD) {
   assert(!CGF.CGM.getTarget().getCXXABI().isMicrosoft() &&
          "No kext in Microsoft ABI");
-  GD = GD.getCanonicalDecl();
   CodeGenModule &CGM = CGF.CGM;
   llvm::Value *VTable = CGM.getCXXABI().getAddrOfVTable(RD, CharUnits());
   Ty = Ty->getPointerTo()->getPointerTo();
@@ -283,7 +282,7 @@ static CGCallee BuildAppleKextVirtualCall(CodeGenFunction &CGF,
     CGF.Builder.CreateConstInBoundsGEP1_64(VTable, VTableIndex, "vfnkxt");
   llvm::Value *VFunc =
     CGF.Builder.CreateAlignedLoad(VFuncPtr, CGF.PointerAlignInBytes);
-  CGCallee Callee(GD.getDecl(), VFunc);
+  CGCallee Callee(GD.getDecl()->getCanonicalDecl(), VFunc);
   return Callee;
 }
 

clang/lib/CodeGen/ItaniumCXXABI.cpp

@@ -825,7 +825,6 @@ ItaniumCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
 llvm::Constant *ItaniumCXXABI::BuildMemberPointer(const CXXMethodDecl *MD,
                                                   CharUnits ThisAdjustment) {
   assert(MD->isInstance() && "Member function must not be static!");
-  MD = MD->getCanonicalDecl();
 
   CodeGenTypes &Types = CGM.getTypes();
 
@@ -1640,7 +1639,6 @@ CGCallee ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
                                                   Address This,
                                                   llvm::Type *Ty,
                                                   SourceLocation Loc) {
-  GD = GD.getCanonicalDecl();
   Ty = Ty->getPointerTo()->getPointerTo();
   auto *MethodDecl = cast<CXXMethodDecl>(GD.getDecl());
   llvm::Value *VTable = CGF.GetVTablePtr(This, Ty, MethodDecl->getParent());
@@ -1674,7 +1672,7 @@ CGCallee ItaniumCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
     VFunc = VFuncLoad;
   }
 
-  CGCallee Callee(MethodDecl, VFunc);
+  CGCallee Callee(MethodDecl->getCanonicalDecl(), VFunc);
   return Callee;
 }
 

clang/lib/CodeGen/MicrosoftCXXABI.cpp

@@ -228,7 +228,6 @@ class MicrosoftCXXABI : public CGCXXABI {
 
   const CXXRecordDecl *
   getThisArgumentTypeForMethod(const CXXMethodDecl *MD) override {
-    MD = MD->getCanonicalDecl();
     if (MD->isVirtual() && !isa<CXXDestructorDecl>(MD)) {
       MethodVFTableLocation ML =
           CGM.getMicrosoftVTableContext().getMethodVFTableLocation(MD);
@@ -1320,10 +1319,8 @@ void MicrosoftCXXABI::EmitCXXDestructors(const CXXDestructorDecl *D) {
 
 CharUnits
 MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
-  GD = GD.getCanonicalDecl();
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
 
-  GlobalDecl LookupGD = GD;
   if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(MD)) {
     // Complete destructors take a pointer to the complete object as a
     // parameter, thus don't need this adjustment.
@@ -1332,11 +1329,11 @@ MicrosoftCXXABI::getVirtualFunctionPrologueThisAdjustment(GlobalDecl GD) {
 
     // There's no Dtor_Base in vftable but it shares the this adjustment with
     // the deleting one, so look it up instead.
-    LookupGD = GlobalDecl(DD, Dtor_Deleting);
+    GD = GlobalDecl(DD, Dtor_Deleting);
   }
 
   MethodVFTableLocation ML =
-      CGM.getMicrosoftVTableContext().getMethodVFTableLocation(LookupGD);
+      CGM.getMicrosoftVTableContext().getMethodVFTableLocation(GD);
   CharUnits Adjustment = ML.VFPtrOffset;
 
   // Normal virtual instance methods need to adjust from the vfptr that first
@@ -1370,7 +1367,6 @@ Address MicrosoftCXXABI::adjustThisArgumentForVirtualFunctionCall(
     return CGF.Builder.CreateConstByteGEP(This, Adjustment);
   }
 
-  GD = GD.getCanonicalDecl();
   const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
 
   GlobalDecl LookupGD = GD;
@@ -1839,7 +1835,6 @@ CGCallee MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
                                                     Address This,
                                                     llvm::Type *Ty,
                                                     SourceLocation Loc) {
-  GD = GD.getCanonicalDecl();
   CGBuilderTy &Builder = CGF.Builder;
 
   Ty = Ty->getPointerTo()->getPointerTo();
@@ -1878,7 +1873,7 @@ CGCallee MicrosoftCXXABI::getVirtualFunctionPointer(CodeGenFunction &CGF,
     VFunc = Builder.CreateAlignedLoad(VFuncPtr, CGF.getPointerAlign());
   }
 
-  CGCallee Callee(MethodDecl, VFunc);
+  CGCallee Callee(MethodDecl->getCanonicalDecl(), VFunc);
   return Callee;
 }
 
@@ -2737,7 +2732,6 @@ llvm::Constant *
 MicrosoftCXXABI::EmitMemberFunctionPointer(const CXXMethodDecl *MD) {
   assert(MD->isInstance() && "Member function must not be static!");
 
-  MD = MD->getCanonicalDecl();
   CharUnits NonVirtualBaseAdjustment = CharUnits::Zero();
   const CXXRecordDecl *RD = MD->getParent()->getMostRecentDecl();
   CodeGenTypes &Types = CGM.getTypes();