Implement constant expression support for __real__ and __imag__ on lvalue
complex numbers. Treat complex numbers as arrays of the corresponding component
type, in order to make std::complex behave properly if implemented in terms of
_Complex T.
Apparently libstdc++'s std::complex is implemented this way, and we were
rejecting a member like this:
constexpr double real() { return __real__ val; }
because it was marked constexpr but unable to produce a constant expression.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@150895 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index fcba037..dda6e84 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -105,6 +105,11 @@
Type = CAT->getElementType();
ArraySize = CAT->getSize().getZExtValue();
MostDerivedLength = I + 1;
+ } else if (Type->isAnyComplexType()) {
+ const ComplexType *CT = Type->castAs<ComplexType>();
+ Type = CT->getElementType();
+ ArraySize = 2;
+ MostDerivedLength = I + 1;
} else if (const FieldDecl *FD = getAsField(Path[I])) {
Type = FD->getType();
ArraySize = 0;
@@ -120,7 +125,7 @@
// The order of this enum is important for diagnostics.
enum CheckSubobjectKind {
CSK_Base, CSK_Derived, CSK_Field, CSK_ArrayToPointer, CSK_ArrayIndex,
- CSK_This
+ CSK_This, CSK_Real, CSK_Imag
};
/// A path from a glvalue to a subobject of that glvalue.
@@ -221,6 +226,18 @@
MostDerivedPathLength = Entries.size();
}
}
+ /// Update this designator to refer to the given complex component.
+ void addComplexUnchecked(QualType EltTy, bool Imag) {
+ PathEntry Entry;
+ Entry.ArrayIndex = Imag;
+ Entries.push_back(Entry);
+
+ // This is technically a most-derived object, though in practice this
+ // is unlikely to matter.
+ MostDerivedType = EltTy;
+ MostDerivedArraySize = 2;
+ MostDerivedPathLength = Entries.size();
+ }
void diagnosePointerArithmetic(EvalInfo &Info, const Expr *E, uint64_t N);
/// Add N to the address of this subobject.
void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) {
@@ -792,6 +809,10 @@
checkSubobject(Info, E, CSK_ArrayToPointer);
Designator.addArrayUnchecked(CAT);
}
+ void addComplex(EvalInfo &Info, const Expr *E, QualType EltTy, bool Imag) {
+ checkSubobject(Info, E, Imag ? CSK_Imag : CSK_Real);
+ Designator.addComplexUnchecked(EltTy, Imag);
+ }
void adjustIndex(EvalInfo &Info, const Expr *E, uint64_t N) {
if (!checkNullPointer(Info, E, CSK_ArrayIndex))
return;
@@ -1420,6 +1441,24 @@
return true;
}
+/// Update an lvalue to refer to a component of a complex number.
+/// \param Info - Information about the ongoing evaluation.
+/// \param LVal - The lvalue to be updated.
+/// \param EltTy - The complex number's component type.
+/// \param Imag - False for the real component, true for the imaginary.
+static bool HandleLValueComplexElement(EvalInfo &Info, const Expr *E,
+ LValue &LVal, QualType EltTy,
+ bool Imag) {
+ if (Imag) {
+ CharUnits SizeOfComponent;
+ if (!HandleSizeof(Info, E->getExprLoc(), EltTy, SizeOfComponent))
+ return false;
+ LVal.Offset += SizeOfComponent;
+ }
+ LVal.addComplex(Info, E, EltTy, Imag);
+ return true;
+}
+
/// Try to evaluate the initializer for a variable declaration.
static bool EvaluateVarDeclInit(EvalInfo &Info, const Expr *E,
const VarDecl *VD,
@@ -1566,6 +1605,25 @@
else
O = &O->getArrayFiller();
ObjType = CAT->getElementType();
+ } else if (ObjType->isAnyComplexType()) {
+ // Next subobject is a complex number.
+ uint64_t Index = Sub.Entries[I].ArrayIndex;
+ if (Index > 1) {
+ Info.Diag(E->getExprLoc(), Info.getLangOpts().CPlusPlus0x ?
+ (unsigned)diag::note_constexpr_read_past_end :
+ (unsigned)diag::note_invalid_subexpr_in_const_expr);
+ return false;
+ }
+ assert(I == N - 1 && "extracting subobject of scalar?");
+ if (O->isComplexInt()) {
+ Obj = CCValue(Index ? O->getComplexIntImag()
+ : O->getComplexIntReal());
+ } else {
+ assert(O->isComplexFloat());
+ Obj = CCValue(Index ? O->getComplexFloatImag()
+ : O->getComplexFloatReal());
+ }
+ return true;
} else if (const FieldDecl *Field = getAsField(Sub.Entries[I])) {
if (Field->isMutable()) {
Info.Diag(E->getExprLoc(), diag::note_constexpr_ltor_mutable, 1)
@@ -1628,13 +1686,17 @@
bool &WasArrayIndex) {
unsigned I = 0, N = std::min(A.Entries.size(), B.Entries.size());
for (/**/; I != N; ++I) {
- if (!ObjType.isNull() && ObjType->isArrayType()) {
+ if (!ObjType.isNull() &&
+ (ObjType->isArrayType() || ObjType->isAnyComplexType())) {
// Next subobject is an array element.
if (A.Entries[I].ArrayIndex != B.Entries[I].ArrayIndex) {
WasArrayIndex = true;
return I;
}
- ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
+ if (ObjType->isAnyComplexType())
+ ObjType = ObjType->castAs<ComplexType>()->getElementType();
+ else
+ ObjType = ObjType->castAsArrayTypeUnsafe()->getElementType();
} else {
if (A.Entries[I].BaseOrMember != B.Entries[I].BaseOrMember) {
WasArrayIndex = false;
@@ -2870,6 +2932,8 @@
bool VisitCXXTypeidExpr(const CXXTypeidExpr *E);
bool VisitArraySubscriptExpr(const ArraySubscriptExpr *E);
bool VisitUnaryDeref(const UnaryOperator *E);
+ bool VisitUnaryReal(const UnaryOperator *E);
+ bool VisitUnaryImag(const UnaryOperator *E);
bool VisitCastExpr(const CastExpr *E) {
switch (E->getCastKind()) {
@@ -2889,9 +2953,6 @@
return HandleBaseToDerivedCast(Info, E, Result);
}
}
-
- // FIXME: Missing: __real__, __imag__
-
};
} // end anonymous namespace
@@ -3015,6 +3076,24 @@
return EvaluatePointer(E->getSubExpr(), Result, Info);
}
+bool LValueExprEvaluator::VisitUnaryReal(const UnaryOperator *E) {
+ if (!Visit(E->getSubExpr()))
+ return false;
+ // __real is a no-op on scalar lvalues.
+ if (E->getSubExpr()->getType()->isAnyComplexType())
+ HandleLValueComplexElement(Info, E, Result, E->getType(), false);
+ return true;
+}
+
+bool LValueExprEvaluator::VisitUnaryImag(const UnaryOperator *E) {
+ assert(E->getSubExpr()->getType()->isAnyComplexType() &&
+ "lvalue __imag__ on scalar?");
+ if (!Visit(E->getSubExpr()))
+ return false;
+ HandleLValueComplexElement(Info, E, Result, E->getType(), true);
+ return true;
+}
+
//===----------------------------------------------------------------------===//
// Pointer Evaluation
//===----------------------------------------------------------------------===//