r282556 - P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Tue Sep 27 16:44:23 PDT 2016
Author: rsmith
Date: Tue Sep 27 18:44:22 2016
New Revision: 282556
URL: http://llvm.org/viewvc/llvm-project?rev=282556&view=rev
Log:
P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of
assignment and compound-assignment operators before the left-hand side. (Even
if it's an overloaded operator.)
This completes the implementation of P0145R3 + P0400R0 for all targets except
Windows, where the evaluation order guarantees for <<, >>, and ->* are
unimplementable as the ABI requires the function arguments are evaluated from
right to left (because parameter destructors are run from left to right in the
callee).
Modified:
cfe/trunk/include/clang/AST/ExprCXX.h
cfe/trunk/lib/CodeGen/CGCall.cpp
cfe/trunk/lib/CodeGen/CGExpr.cpp
cfe/trunk/lib/CodeGen/CGExprCXX.cpp
cfe/trunk/lib/CodeGen/CodeGenFunction.h
cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp
cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm
cfe/trunk/www/cxx_status.html
Modified: cfe/trunk/include/clang/AST/ExprCXX.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ExprCXX.h?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/ExprCXX.h (original)
+++ cfe/trunk/include/clang/AST/ExprCXX.h Tue Sep 27 18:44:22 2016
@@ -76,6 +76,16 @@ public:
/// expression refers to.
OverloadedOperatorKind getOperator() const { return Operator; }
+ static bool isAssignmentOp(OverloadedOperatorKind Opc) {
+ return Opc == OO_Equal || Opc == OO_StarEqual ||
+ Opc == OO_SlashEqual || Opc == OO_PercentEqual ||
+ Opc == OO_PlusEqual || Opc == OO_MinusEqual ||
+ Opc == OO_LessLessEqual || Opc == OO_GreaterGreaterEqual ||
+ Opc == OO_AmpEqual || Opc == OO_CaretEqual ||
+ Opc == OO_PipeEqual;
+ }
+ bool isAssignmentOp() const { return isAssignmentOp(getOperator()); }
+
/// \brief Returns the location of the operator symbol in the expression.
///
/// When \c getOperator()==OO_Call, this is the location of the right
Modified: cfe/trunk/lib/CodeGen/CGCall.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGCall.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGCall.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGCall.cpp Tue Sep 27 18:44:22 2016
@@ -3172,7 +3172,8 @@ void CodeGenFunction::EmitNonNullArgChec
void CodeGenFunction::EmitCallArgs(
CallArgList &Args, ArrayRef<QualType> ArgTypes,
llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
- const FunctionDecl *CalleeDecl, unsigned ParamsToSkip) {
+ const FunctionDecl *CalleeDecl, unsigned ParamsToSkip,
+ bool ForceRightToLeftEvaluation) {
assert((int)ArgTypes.size() == (ArgRange.end() - ArgRange.begin()));
auto MaybeEmitImplicitObjectSize = [&](unsigned I, const Expr *Arg) {
@@ -3191,7 +3192,8 @@ void CodeGenFunction::EmitCallArgs(
// We *have* to evaluate arguments from right to left in the MS C++ ABI,
// because arguments are destroyed left to right in the callee.
- if (CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee()) {
+ if (CGM.getTarget().getCXXABI().areArgsDestroyedLeftToRightInCallee() ||
+ ForceRightToLeftEvaluation) {
// Insert a stack save if we're going to need any inalloca args.
bool HasInAllocaArgs = false;
for (ArrayRef<QualType>::iterator I = ArgTypes.begin(), E = ArgTypes.end();
Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExpr.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExpr.cpp Tue Sep 27 18:44:22 2016
@@ -4121,8 +4121,17 @@ RValue CodeGenFunction::EmitCall(QualTyp
if (Chain)
Args.add(RValue::get(Builder.CreateBitCast(Chain, CGM.VoidPtrTy)),
CGM.getContext().VoidPtrTy);
+
+ // C++17 requires that we evaluate arguments to a call using assignment syntax
+ // right-to-left. It also requires that we evaluate arguments to operators
+ // <<, >>, and ->* left-to-right, but that is not possible under the MS ABI,
+ // so there is no corresponding "force left-to-right" case.
+ bool ForceRightToLeft = false;
+ if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(E))
+ ForceRightToLeft = OCE->isAssignmentOp();
+
EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), E->arguments(),
- E->getDirectCallee(), /*ParamsToSkip*/ 0);
+ E->getDirectCallee(), /*ParamsToSkip*/ 0, ForceRightToLeft);
const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeFreeFunctionCall(
Args, FnType, /*isChainCall=*/Chain);
Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Tue Sep 27 18:44:22 2016
@@ -28,7 +28,7 @@ static RequiredArgs
commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
llvm::Value *This, llvm::Value *ImplicitParam,
QualType ImplicitParamTy, const CallExpr *CE,
- CallArgList &Args) {
+ CallArgList &Args, CallArgList *RtlArgs) {
assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
isa<CXXOperatorCallExpr>(CE));
assert(MD->isInstance() &&
@@ -61,7 +61,12 @@ commonEmitCXXMemberOrOperatorCall(CodeGe
RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size(), MD);
// And the rest of the call args.
- if (CE) {
+ if (RtlArgs) {
+ // Special case: if the caller emitted the arguments right-to-left already
+ // (prior to emitting the *this argument), we're done. This happens for
+ // assignment operators.
+ Args.addFrom(*RtlArgs);
+ } else if (CE) {
// Special case: skip first argument of CXXOperatorCall (it is "this").
unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
@@ -77,11 +82,11 @@ commonEmitCXXMemberOrOperatorCall(CodeGe
RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue,
llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
- const CallExpr *CE) {
+ const CallExpr *CE, CallArgList *RtlArgs) {
const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
CallArgList Args;
RequiredArgs required = commonEmitCXXMemberOrOperatorCall(
- *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args);
+ *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
Callee, ReturnValue, Args, MD);
}
@@ -92,7 +97,7 @@ RValue CodeGenFunction::EmitCXXDestructo
StructorType Type) {
CallArgList Args;
commonEmitCXXMemberOrOperatorCall(*this, DD, This, ImplicitParam,
- ImplicitParamTy, CE, Args);
+ ImplicitParamTy, CE, Args, nullptr);
return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(DD, Type),
Callee, ReturnValueSlot(), Args, DD);
}
@@ -170,6 +175,19 @@ RValue CodeGenFunction::EmitCXXMemberOrO
}
}
+ // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
+ // operator before the LHS.
+ CallArgList RtlArgStorage;
+ CallArgList *RtlArgs = nullptr;
+ if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
+ if (OCE->isAssignmentOp()) {
+ RtlArgs = &RtlArgStorage;
+ EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
+ drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
+ /*ParamsToSkip*/0, /*ForceRightToLeftEvaluation*/true);
+ }
+ }
+
Address This = Address::invalid();
if (IsArrow)
This = EmitPointerWithAlignment(Base);
@@ -187,10 +205,12 @@ RValue CodeGenFunction::EmitCXXMemberOrO
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.
- // Special case: skip first argument of CXXOperatorCall (it is "this").
- unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
- Address RHS = EmitLValue(*(CE->arg_begin() + ArgsToSkip)).getAddress();
- EmitAggregateAssign(This, RHS, CE->getType());
+ LValue RHS = isa<CXXOperatorCallExpr>(CE)
+ ? MakeNaturalAlignAddrLValue(
+ (*RtlArgs)[0].RV.getScalarVal(),
+ (*(CE->arg_begin() + 1))->getType())
+ : EmitLValue(*CE->arg_begin());
+ EmitAggregateAssign(This, RHS.getAddress(), CE->getType());
return RValue::get(This.getPointer());
}
@@ -249,7 +269,8 @@ RValue CodeGenFunction::EmitCXXMemberOrO
Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty);
}
EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),
- /*ImplicitParam=*/nullptr, QualType(), CE);
+ /*ImplicitParam=*/nullptr, QualType(), CE,
+ nullptr);
}
return RValue::get(nullptr);
}
@@ -282,7 +303,8 @@ RValue CodeGenFunction::EmitCXXMemberOrO
}
return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This.getPointer(),
- /*ImplicitParam=*/nullptr, QualType(), CE);
+ /*ImplicitParam=*/nullptr, QualType(), CE,
+ RtlArgs);
}
RValue
Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.h?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h (original)
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h Tue Sep 27 18:44:22 2016
@@ -2867,7 +2867,8 @@ public:
EmitCXXMemberOrOperatorCall(const CXXMethodDecl *MD, llvm::Value *Callee,
ReturnValueSlot ReturnValue, llvm::Value *This,
llvm::Value *ImplicitParam,
- QualType ImplicitParamTy, const CallExpr *E);
+ QualType ImplicitParamTy, const CallExpr *E,
+ CallArgList *RtlArgs);
RValue EmitCXXDestructorCall(const CXXDestructorDecl *DD, llvm::Value *Callee,
llvm::Value *This, llvm::Value *ImplicitParam,
QualType ImplicitParamTy, const CallExpr *E,
@@ -3322,7 +3323,8 @@ public:
void EmitCallArgs(CallArgList &Args, const T *CallArgTypeInfo,
llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
const FunctionDecl *CalleeDecl = nullptr,
- unsigned ParamsToSkip = 0) {
+ unsigned ParamsToSkip = 0,
+ bool ForceRightToLeftEvaluation = false) {
SmallVector<QualType, 16> ArgTypes;
CallExpr::const_arg_iterator Arg = ArgRange.begin();
@@ -3362,13 +3364,15 @@ public:
for (auto *A : llvm::make_range(Arg, ArgRange.end()))
ArgTypes.push_back(getVarArgType(A));
- EmitCallArgs(Args, ArgTypes, ArgRange, CalleeDecl, ParamsToSkip);
+ EmitCallArgs(Args, ArgTypes, ArgRange, CalleeDecl, ParamsToSkip,
+ ForceRightToLeftEvaluation);
}
void EmitCallArgs(CallArgList &Args, ArrayRef<QualType> ArgTypes,
llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
const FunctionDecl *CalleeDecl = nullptr,
- unsigned ParamsToSkip = 0);
+ unsigned ParamsToSkip = 0,
+ bool ForceRightToLeftEvaluation = false);
/// EmitPointerWithAlignment - Given an expression with a pointer
/// type, emit the value and compute our best estimate of the
Modified: cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp (original)
+++ cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp Tue Sep 27 18:44:22 2016
@@ -1456,7 +1456,8 @@ void ItaniumCXXABI::EmitDestructorCall(C
Callee = CGM.getAddrOfCXXStructor(DD, getFromDtorType(Type));
CGF.EmitCXXMemberOrOperatorCall(DD, Callee, ReturnValueSlot(),
- This.getPointer(), VTT, VTTTy, nullptr);
+ This.getPointer(), VTT, VTTTy,
+ nullptr, nullptr);
}
void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
@@ -1636,7 +1637,7 @@ llvm::Value *ItaniumCXXABI::EmitVirtualD
CGF.EmitCXXMemberOrOperatorCall(Dtor, Callee, ReturnValueSlot(),
This.getPointer(), /*ImplicitParam=*/nullptr,
- QualType(), CE);
+ QualType(), CE, nullptr);
return nullptr;
}
Modified: cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/cxx1z-eval-order.cpp Tue Sep 27 18:44:22 2016
@@ -18,7 +18,8 @@ struct B {
struct C {
operator int *();
A *operator->();
- void operator->*(B);
+ void operator->*(A);
+ friend void operator->*(C, B);
friend void operator<<(C, B);
friend void operator>>(C, B);
@@ -137,7 +138,17 @@ int dotstar_lhs_before_rhs() {
int b = make_a_ptr()->*make_mem_ptr_a();
// CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
- // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
+ make_c()->*make_a();
+
+ // FIXME: The corresponding case for Windows ABIs is unimplementable if the
+ // operand has a non-trivially-destructible type, because the order of
+ // construction of function arguments is defined by the ABI there (it's the
+ // reverse of the order in which the parameters are destroyed in the callee).
+ // But we could follow the C++17 rule in the case where the operand type is
+ // trivially-destructible.
+ // CHECK-ITANIUM: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK-ITANIUM: call {{.*}}@{{.*}}make_b{{.*}}(
make_c()->*make_b();
// CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
@@ -154,61 +165,60 @@ int dotstar_lhs_before_rhs() {
// CHECK: }
}
-#if 0
-// CHECKDISABLED-LABEL: define {{.*}}@{{.*}}assign_lhs_before_rhs{{.*}}(
+
+// CHECK-LABEL: define {{.*}}@{{.*}}assign_rhs_before_lhs{{.*}}(
void assign_rhs_before_lhs() {
extern int &lhs_ref(), rhs();
- // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}lhs_ref{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}lhs_ref{{.*}}(
lhs_ref() = rhs();
- // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}lhs_ref{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}lhs_ref{{.*}}(
lhs_ref() += rhs();
- // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}lhs_ref{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}lhs_ref{{.*}}(
lhs_ref() %= rhs();
- // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
make_c() = make_b();
- // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
make_c() += make_b();
-// CHECKDISABLED: }
+// CHECK: }
}
-#endif
-#if 0
-// CHECKDISABLED-LABEL: define {{.*}}@{{.*}}shift_lhs_before_rhs{{.*}}(
+
+// CHECK-LABEL: define {{.*}}@{{.*}}shift_lhs_before_rhs{{.*}}(
void shift_lhs_before_rhs() {
extern int lhs(), rhs();
- // CHECKDISABLED: call {{.*}}@{{.*}}lhs{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}lhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
(void)(lhs() << rhs());
- // CHECKDISABLED: call {{.*}}@{{.*}}lhs{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}rhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}lhs{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}rhs{{.*}}(
(void)(lhs() >> rhs());
- // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}make_a{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
make_c() << make_a();
- // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}make_a{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_a{{.*}}(
make_c() >> make_a();
- // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK: call {{.*}}@{{.*}}make_b{{.*}}(
make_c() << make_b();
- // CHECKDISABLED: call {{.*}}@{{.*}}make_c{{.*}}(
- // CHECKDISABLED: call {{.*}}@{{.*}}make_b{{.*}}(
+ // FIXME: This is unimplementable for Windows ABIs, see above.
+ // CHECK-ITANIUM: call {{.*}}@{{.*}}make_c{{.*}}(
+ // CHECK-ITANIUM: call {{.*}}@{{.*}}make_b{{.*}}(
make_c() >> make_b();
-// CHECKDISABLED: }
+// CHECK: }
}
-#endif
Modified: cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm (original)
+++ cfe/trunk/test/CodeGenObjCXX/property-object-reference-2.mm Tue Sep 27 18:44:22 2016
@@ -44,8 +44,8 @@ struct TCPPObject
// CHECK: ret void
// CHECK-LABEL: define internal void @__assign_helper_atomic_property_(%struct.TCPPObject*, %struct.TCPPObject*) #
-// CHECK: [[TWO:%.*]] = load %struct.TCPPObject*, %struct.TCPPObject** [[ADDR:%.*]], align 8
// CHECK: [[THREE:%.*]] = load %struct.TCPPObject*, %struct.TCPPObject** [[ADDR1:%.*]], align 8
+// CHECK: [[TWO:%.*]] = load %struct.TCPPObject*, %struct.TCPPObject** [[ADDR:%.*]], align 8
// CHECK: [[CALL:%.*]] = call dereferenceable({{[0-9]+}}) %struct.TCPPObject* @_ZN10TCPPObjectaSERKS_(%struct.TCPPObject* [[TWO]], %struct.TCPPObject* dereferenceable({{[0-9]+}}) [[THREE]])
// CHECK: ret void
Modified: cfe/trunk/www/cxx_status.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=282556&r1=282555&r2=282556&view=diff
==============================================================================
--- cfe/trunk/www/cxx_status.html (original)
+++ cfe/trunk/www/cxx_status.html Tue Sep 27 18:44:22 2016
@@ -701,7 +701,7 @@ as the draft C++1z standard evolves.</p>
<tr>
<td rowspan=2>Stricter expression evaluation order</td>
<td><a href="http://wg21.link/p0145r3">P0145R3</a></td>
- <td class="none" align="center" rowspan=2>No</td>
+ <td class="svn" align="center" rowspan=2>SVN <a href="#p0145">(10)</a></td>
</tr>
<tr>
<td><a href="http://wg21.link/p0400r0">P0400R0</a></td>
@@ -741,6 +741,14 @@ In Clang 3.7, a warning is emitted for a
</span><br>
<span id="p0136">(9): This is the resolution to a Defect Report, so is applied
to all language versions supporting inheriting constructors.
+</span><br>
+<span id="p0145">(10): Under the MS ABI, this feature is not fully implementable,
+because the calling convention requires that function parameters are destroyed
+from left to right in the callee. In order to guarantee that destruction order
+is reverse construction order, the operands of overloaded
+<tt>operator<<</tt>, <tt>operator>></tt>, and <tt>operator->*</tt>
+functions are evaluated right-to-left under the MS ABI when called using operator
+syntax, not left-to-right as P0145R3 requires.
</span>
</p>
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