From ab4f7f144a633329fb8f619c4133d69606dd0d2a Mon Sep 17 00:00:00 2001
From: James Y Knight <jyknight@google.com>
Date: Wed, 6 Feb 2019 00:06:03 +0000
Subject: Fix MSVC constructor call extension after b92d290e48e9 (r353181).

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.

Ref: https://bugs.chromium.org/p/chromium/issues/detail?id=928861
Differential Revision: https://reviews.llvm.org/D57794

llvm-svn: 353246
---
 clang/lib/CodeGen/CGExprCXX.cpp | 51 ++++++++++++++++-------------------------
 1 file changed, 20 insertions(+), 31 deletions(-)

(limited to 'clang/lib/CodeGen/CGExprCXX.cpp')

diff --git a/clang/lib/CodeGen/CGExprCXX.cpp b/clang/lib/CodeGen/CGExprCXX.cpp
index 13612d377c6..e5cc22a1196 100644
--- a/clang/lib/CodeGen/CGExprCXX.cpp
+++ b/clang/lib/CodeGen/CGExprCXX.cpp
@@ -249,13 +249,25 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
     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
@@ -268,20 +280,6 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
         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");
     }
   }
@@ -293,9 +291,6 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
   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);
 
@@ -318,11 +313,9 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
     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()),
-      /*Alignment=*/CharUnits::Zero(), SkippedChecks);
+  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
@@ -366,11 +359,7 @@ RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
   // '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) &&
-- 
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