Fix MSVC constructor call extension after b92d290e48e9 (r353181).

[jyknight]

Summary

The assert added to EmitCall there was triggering in Windows Chromium
builds, due to a mismatch of the return type.

The MSVC constructor call extension (this->Foo::Foo()) was emitting
the constructor call from 'EmitCXXMemberOrOperatorMemberCallExpr' via
calling 'EmitCXXMemberOrOperatorCall', instead of
'EmitCXXConstructorCall'. On targets where HasThisReturn is true, that
was failing to set the proper return type in the call info.

Switching to calling EmitCXXConstructorCall also allowed removing some
code e.g. the trivial copy/move support, which is already handled in
EmitCXXConstructorCall.

[rnk]

lgtm

clang/lib/CodeGen/CGExprCXX.cpp

if (IsArrow) {
     LValueBaseInfo BaseInfo;
     TBAAAccessInfo TBAAInfo;
     Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
     This = MakeAddrLValue(ThisValue, Base->getType(), BaseInfo, TBAAInfo);
   } else {
     This = EmitLValue(Base);
   }
 
+  if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
+    // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
+    // constructing a new complete object of type Ctor.
+    assert(!RtlArgs);
+    assert(ReturnValue.isNull() && "Constructor shouldn't have return value");
+    CallArgList Args;
+    commonEmitCXXMemberOrOperatorCall(
+        *this, Ctor, This.getPointer(), /*ImplicitParam=*/nullptr,
+        /*ImplicitParamTy=*/QualType(), CE, Args, nullptr);
+
+    EmitCXXConstructorCall(Ctor, Ctor_Complete, /*ForVirtualBase=*/false,
+                           /*Delegating=*/false, This.getAddress(), Args,
+                           AggValueSlot::DoesNotOverlap, CE->getExprLoc(),
+                           /*NewPointerIsChecked=*/false);
+    return RValue::get(nullptr);
+  }
 
   if (MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion())) {
     if (isa<CXXDestructorDecl>(MD)) return RValue::get(nullptr);
-    if (isa<CXXConstructorDecl>(MD) &&
-        cast<CXXConstructorDecl>(MD)->isDefaultConstructor())
-      return RValue::get(nullptr);
-
     if (!MD->getParent()->mayInsertExtraPadding()) {
       if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) {
         // We don't like to generate the trivial copy/move assignment operator
         // when it isn't necessary; just produce the proper effect here.
         LValue RHS = isa<CXXOperatorCallExpr>(CE)
                          ? MakeNaturalAlignAddrLValue(
                                (*RtlArgs)[0].getRValue(*this).getScalarVal(),
                                (*(CE->arg_begin() + 1))->getType())
                          : EmitLValue(*CE->arg_begin());
         EmitAggregateAssign(This, RHS, CE->getType());
         return RValue::get(This.getPointer());
       }
-
-      if (isa<CXXConstructorDecl>(MD) &&
-          cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) {
-        // Trivial move and copy ctor are the same.
-        assert(CE->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
-        const Expr *Arg = *CE->arg_begin();
-        LValue RHS = EmitLValue(Arg);
-        LValue Dest = MakeAddrLValue(This.getAddress(), Arg->getType());
-        // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
-        // constructing a new complete object of type Ctor.
-        EmitAggregateCopy(Dest, RHS, Arg->getType(),
-                          AggValueSlot::DoesNotOverlap);
-        return RValue::get(This.getPointer());
-      }
       llvm_unreachable("unknown trivial member function");
     }
   }
 
   // Compute the function type we're calling.
   const CXXMethodDecl *CalleeDecl =
       DevirtualizedMethod ? DevirtualizedMethod : MD;
   const CGFunctionInfo *FInfo = nullptr;
   if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
     FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
         Dtor, StructorType::Complete);
-  else if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl))
-    FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
-        Ctor, StructorType::Complete);
   else
     FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
 
   llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
 
   // C++11 [class.mfct.non-static]p2:
   //   If a non-static member function of a class X is called for an object that
   //   is not of type X, or of a type derived from X, the behavior is undefined.
   SourceLocation CallLoc;
   ASTContext &C = getContext();
   if (CE)
     CallLoc = CE->getExprLoc();
 
   SanitizerSet SkippedChecks;
   if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
     auto *IOA = CMCE->getImplicitObjectArgument();
     bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
     if (IsImplicitObjectCXXThis)
       SkippedChecks.set(SanitizerKind::Alignment, true);
     if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
       SkippedChecks.set(SanitizerKind::Null, true);
   }
-  EmitTypeCheck(
-      isa<CXXConstructorDecl>(CalleeDecl) ? CodeGenFunction::TCK_ConstructorCall
-                                          : CodeGenFunction::TCK_MemberCall,
-      CallLoc, This.getPointer(), C.getRecordType(CalleeDecl->getParent()),
+  EmitTypeCheck(CodeGenFunction::TCK_MemberCall, CallLoc, This.getPointer(),
+                C.getRecordType(CalleeDecl->getParent()),
                 /*Alignment=*/CharUnits::Zero(), SkippedChecks);
 
   // C++ [class.virtual]p12:
   //   Explicit qualification with the scope operator (5.1) suppresses the
   //   virtual call mechanism.
   //
   // We also don't emit a virtual call if the base expression has a record type
   // because then we know what the type is.
   bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl)) {
     }
     return RValue::get(nullptr);
   }
 
   // FIXME: Uses of 'MD' past this point need to be audited. We may need to use
   // 'CalleeDecl' instead.
 
   CGCallee Callee;
-  if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
-    Callee = CGCallee::forDirect(
-        CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty),
-        GlobalDecl(Ctor, Ctor_Complete));
-  } else if (UseVirtualCall) {
+  if (UseVirtualCall) {
     Callee = CGCallee::forVirtual(CE, MD, This.getAddress(), Ty);
   } else {
     if (SanOpts.has(SanitizerKind::CFINVCall) &&
         MD->getParent()->isDynamicClass()) {
       llvm::Value *VTable;
       const CXXRecordDecl *RD;
       std::tie(VTable, RD) =
           CGM.getCXXABI().LoadVTablePtr(*this, This.getAddress(),

clang/test/CodeGenCXX/constructor-direct-call.cpp

-// RUN: %clang_cc1 -triple i686-pc-mingw32 -fms-extensions -Wmicrosoft %s -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -triple i686-pc-mingw32 -fms-extensions -Wmicrosoft %s -emit-llvm -o - | FileCheck %s --check-prefix=CHECK32 --check-prefix=CHECK
+// RUN: %clang_cc1 -triple x86_64-pc-windows-msvc19.11.0 -fms-extensions -Wmicrosoft %s -emit-llvm -o - | FileCheck %s --check-prefix=CHECK64 --check-prefix=CHECK
 
 class Test1 {
 public:
    int a;
 };
 
 void f1() {
   Test1 var;
   var.Test1::Test1();
 
-  // CHECK:   call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %{{.*}}, i8* align 4 %{{.*}}, i32 4, i1 false)
+  // CHECK32:   call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %{{.*}}, i8* align 4 %{{.*}}, i32 4, i1 false)
+  // CHECK64:   call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %{{.*}}, i8* align 4 %{{.*}}, i64 4, i1 false)
   var.Test1::Test1(var);
 }
 
 class Test2 {
 public:
   Test2() { a = 10; b = 10; }
    int a;
    int b;
 };
 
 void f2() {
   // CHECK:  %var = alloca %class.Test2, align 4
-  // CHECK-NEXT:  call x86_thiscallcc void @_ZN5Test2C1Ev(%class.Test2* %var)
+  // CHECK32-NEXT:  call x86_thiscallcc void @_ZN5Test2C1Ev(%class.Test2* %var)
+  // CHECK64-NEXT:  %call = call %class.Test2* @"??0Test2@@QEAA@XZ"(%class.Test2* %var)
   Test2 var;
 
-  // CHECK-NEXT:  call x86_thiscallcc void @_ZN5Test2C1Ev(%class.Test2* %var)
+  // CHECK32-NEXT:  call x86_thiscallcc void @_ZN5Test2C1Ev(%class.Test2* %var)
+  // CHECK64-NEXT:  %call1 = call %class.Test2* @"??0Test2@@QEAA@XZ"(%class.Test2* %var)
   var.Test2::Test2();
 
-  // CHECK:  call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %{{.*}}, i8* align 4 %{{.*}}, i32 8, i1 false)
+  // CHECK32:  call void @llvm.memcpy.p0i8.p0i8.i32(i8* align 4 %{{.*}}, i8* align 4 %{{.*}}, i32 8, i1 false)
+  // CHECK64:  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %{{.*}}, i8* align 4 %{{.*}}, i64 8, i1 false)
   var.Test2::Test2(var);
 }
 
 
 
 
 class Test3 {
 public:
   Test3() { a = 10; b = 15; c = 20; }
   Test3(const Test3& that) { a = that.a; b = that.b; c = that.c; }
    int a;
    int b;
    int c;
 };
 
 void f3() {
-  // CHECK: call x86_thiscallcc void @_ZN5Test3C1Ev(%class.Test3* %var)
+  // CHECK32: call x86_thiscallcc void @_ZN5Test3C1Ev(%class.Test3* %var)
+  // CHECK64: %call = call %class.Test3* @"??0Test3@@QEAA@XZ"(%class.Test3* %var)
   Test3 var;
 
-  // CHECK-NEXT: call x86_thiscallcc void @_ZN5Test3C1Ev(%class.Test3* %var2)
+  // CHECK32-NEXT: call x86_thiscallcc void @_ZN5Test3C1Ev(%class.Test3* %var2)
+  // CHECK64-NEXT: %call1 = call %class.Test3* @"??0Test3@@QEAA@XZ"(%class.Test3* %var2)
   Test3 var2;
 
-  // CHECK-NEXT: call x86_thiscallcc void @_ZN5Test3C1Ev(%class.Test3* %var)
+  // CHECK32-NEXT: call x86_thiscallcc void @_ZN5Test3C1Ev(%class.Test3* %var)
+  // CHECK64-NEXT: %call2 = call %class.Test3* @"??0Test3@@QEAA@XZ"(%class.Test3* %var)
   var.Test3::Test3();
 
-  // CHECK-NEXT: call x86_thiscallcc void @_ZN5Test3C1ERKS_(%class.Test3* %var, %class.Test3* dereferenceable({{[0-9]+}}) %var2)
+  // CHECK32-NEXT: call x86_thiscallcc void @_ZN5Test3C1ERKS_(%class.Test3* %var, %class.Test3* dereferenceable({{[0-9]+}}) %var2)
+  // CHECK64-NEXT: %call3 = call %class.Test3* @"??0Test3@@QEAA@AEBV0@@Z"(%class.Test3* %var, %class.Test3* dereferenceable({{[0-9]+}}) %var2)
   var.Test3::Test3(var2);
 }