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PR32034: Evaluate _Atomic(T) in-place when T is a class or array type. 

This is necessary in order for the evaluation of an _Atomic initializer for
those types to have an associated object, which an initializer for class or
array type needs.

llvm-svn: 295886
This commit is contained in:
Richard Smith 2017-02-22 22:09:50 +00:00
parent 835b246d7f
commit 64cb9ca456
2 changed files with 46 additions and 12 deletions
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47
clang/lib/AST/ExprConstant.cpp
View File

@ -1437,7 +1437,8 @@ static bool EvaluateIntegerOrLValue(const Expr *E, APValue &Result,
EvalInfo &Info);
static bool EvaluateFloat(const Expr *E, APFloat &Result, EvalInfo &Info);
static bool EvaluateComplex(const Expr *E, ComplexValue &Res, EvalInfo &Info);
static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info);
static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
EvalInfo &Info);
static bool EvaluateAsRValue(EvalInfo &Info, const Expr *E, APValue &Result);
//===----------------------------------------------------------------------===//
@ -4743,7 +4744,10 @@ public:
case CK_AtomicToNonAtomic: {
APValue AtomicVal;
if (!EvaluateAtomic(E->getSubExpr(), AtomicVal, Info))
// This does not need to be done in place even for class/array types:
// atomic-to-non-atomic conversion implies copying the object
// representation.
if (!Evaluate(AtomicVal, Info, E->getSubExpr()))
return false;
return DerivedSuccess(AtomicVal, E);
}
@ -9689,10 +9693,11 @@ bool ComplexExprEvaluator::VisitInitListExpr(const InitListExpr *E) {
namespace {
class AtomicExprEvaluator :
public ExprEvaluatorBase<AtomicExprEvaluator> {
const LValue *This;
APValue &Result;
public:
AtomicExprEvaluator(EvalInfo &Info, APValue &Result)
: ExprEvaluatorBaseTy(Info), Result(Result) {}
AtomicExprEvaluator(EvalInfo &Info, const LValue *This, APValue &Result)
: ExprEvaluatorBaseTy(Info), This(This), Result(Result) {}
bool Success(const APValue &V, const Expr *E) {
Result = V;
@ -9702,7 +9707,10 @@ public:
bool ZeroInitialization(const Expr *E) {
ImplicitValueInitExpr VIE(
E->getType()->castAs<AtomicType>()->getValueType());
return Evaluate(Result, Info, &VIE);
// For atomic-qualified class (and array) types in C++, initialize the
// _Atomic-wrapped subobject directly, in-place.
return This ? EvaluateInPlace(Result, Info, *This, &VIE)
: Evaluate(Result, Info, &VIE);
}
bool VisitCastExpr(const CastExpr *E) {
@ -9710,15 +9718,17 @@ public:
default:
return ExprEvaluatorBaseTy::VisitCastExpr(E);
case CK_NonAtomicToAtomic:
return Evaluate(Result, Info, E->getSubExpr());
return This ? EvaluateInPlace(Result, Info, *This, E->getSubExpr())
: Evaluate(Result, Info, E->getSubExpr());
}
}
};
} // end anonymous namespace
static bool EvaluateAtomic(const Expr *E, APValue &Result, EvalInfo &Info) {
static bool EvaluateAtomic(const Expr *E, const LValue *This, APValue &Result,
EvalInfo &Info) {
assert(E->isRValue() && E->getType()->isAtomicType());
return AtomicExprEvaluator(Info, Result).Visit(E);
return AtomicExprEvaluator(Info, This, Result).Visit(E);
}
//===----------------------------------------------------------------------===//
@ -9823,8 +9833,17 @@ static bool Evaluate(APValue &Result, EvalInfo &Info, const Expr *E) {
if (!EvaluateVoid(E, Info))
return false;
} else if (T->isAtomicType()) {
if (!EvaluateAtomic(E, Result, Info))
QualType Unqual = T.getAtomicUnqualifiedType();
if (Unqual->isArrayType() || Unqual->isRecordType()) {
LValue LV;
LV.set(E, Info.CurrentCall->Index);
APValue &Value = Info.CurrentCall->createTemporary(E, false);
if (!EvaluateAtomic(E, &LV, Value, Info))
return false;
} else {
if (!EvaluateAtomic(E, nullptr, Result, Info))
return false;
}
} else if (Info.getLangOpts().CPlusPlus11) {
Info.FFDiag(E, diag::note_constexpr_nonliteral) << E->getType();
return false;
@ -9849,10 +9868,16 @@ static bool EvaluateInPlace(APValue &Result, EvalInfo &Info, const LValue &This,
if (E->isRValue()) {
// Evaluate arrays and record types in-place, so that later initializers can
// refer to earlier-initialized members of the object.
if (E->getType()->isArrayType())
QualType T = E->getType();
if (T->isArrayType())
return EvaluateArray(E, This, Result, Info);
else if (E->getType()->isRecordType())
else if (T->isRecordType())
return EvaluateRecord(E, This, Result, Info);
else if (T->isAtomicType()) {
QualType Unqual = T.getAtomicUnqualifiedType();
if (Unqual->isArrayType() || Unqual->isRecordType())
return EvaluateAtomic(E, &This, Result, Info);
}
}
// For any other type, in-place evaluation is unimportant.

9
clang/test/SemaCXX/constant-expression-cxx11.cpp
View File

@ -1280,6 +1280,15 @@ namespace Atomic {
constexpr TestVar testVar{-1};
static_assert(testVar.value == -1, "");
}
namespace PR32034 {
struct A {};
struct B { _Atomic(A) a; };
constexpr int n = (B(), B(), 0);
struct C { constexpr C() {} void *self = this; };
constexpr _Atomic(C) c = C();
}
}
namespace InstantiateCaseStmt {