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Diffstat (limited to 'clang/lib/AST/ExprConstant.cpp')
-rw-r--r--clang/lib/AST/ExprConstant.cpp69
1 files changed, 27 insertions, 42 deletions
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index bf92087..81c778e 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -202,7 +202,9 @@ namespace {
assert(!isBaseAnAllocSizeCall(Base) &&
"Unsized arrays shouldn't appear here");
unsigned MostDerivedLength = 0;
- Type = getType(Base);
+ // The type of Base is a reference type if the base is a constexpr-unknown
+ // variable. In that case, look through the reference type.
+ Type = getType(Base).getNonReferenceType();
for (unsigned I = 0, N = Path.size(); I != N; ++I) {
if (Type->isArrayType()) {
@@ -289,7 +291,7 @@ namespace {
: Invalid(false), IsOnePastTheEnd(false),
FirstEntryIsAnUnsizedArray(false), MostDerivedIsArrayElement(false),
MostDerivedPathLength(0), MostDerivedArraySize(0),
- MostDerivedType(T) {}
+ MostDerivedType(T.isNull() ? QualType() : T.getNonReferenceType()) {}
SubobjectDesignator(ASTContext &Ctx, const APValue &V)
: Invalid(!V.isLValue() || !V.hasLValuePath()), IsOnePastTheEnd(false),
@@ -571,7 +573,6 @@ namespace {
typedef std::map<MapKeyTy, APValue> MapTy;
/// Temporaries - Temporary lvalues materialized within this stack frame.
MapTy Temporaries;
- MapTy ConstexprUnknownAPValues;
/// CallRange - The source range of the call expression for this call.
SourceRange CallRange;
@@ -646,9 +647,6 @@ namespace {
APValue &createTemporary(const KeyT *Key, QualType T,
ScopeKind Scope, LValue &LV);
- APValue &createConstexprUnknownAPValues(const VarDecl *Key,
- APValue::LValueBase Base);
-
/// Allocate storage for a parameter of a function call made in this frame.
APValue &createParam(CallRef Args, const ParmVarDecl *PVD, LValue &LV);
@@ -1756,7 +1754,8 @@ namespace {
return;
}
if (checkSubobject(Info, E, CSK_ArrayToPointer)) {
- assert(getType(Base)->isPointerType() || getType(Base)->isArrayType());
+ assert(getType(Base).getNonReferenceType()->isPointerType() ||
+ getType(Base).getNonReferenceType()->isArrayType());
Designator.FirstEntryIsAnUnsizedArray = true;
Designator.addUnsizedArrayUnchecked(ElemTy);
}
@@ -1955,15 +1954,6 @@ APValue &CallStackFrame::createTemporary(const KeyT *Key, QualType T,
return createLocal(Base, Key, T, Scope);
}
-APValue &
-CallStackFrame::createConstexprUnknownAPValues(const VarDecl *Key,
- APValue::LValueBase Base) {
- APValue &Result = ConstexprUnknownAPValues[MapKeyTy(Key, Base.getVersion())];
- Result = APValue(Base, CharUnits::Zero(), APValue::ConstexprUnknown{});
-
- return Result;
-}
-
/// Allocate storage for a parameter of a function call made in this frame.
APValue &CallStackFrame::createParam(CallRef Args, const ParmVarDecl *PVD,
LValue &LV) {
@@ -3493,7 +3483,7 @@ static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
APValue::LValueBase Base(VD, Frame ? Frame->Index : 0, Version);
auto CheckUninitReference = [&](bool IsLocalVariable) {
- if (!Result->hasValue() && VD->getType()->isReferenceType()) {
+ if (!Result || (!Result->hasValue() && VD->getType()->isReferenceType())) {
// C++23 [expr.const]p8
// ... For such an object that is not usable in constant expressions, the
// dynamic type of the object is constexpr-unknown. For such a reference
@@ -3509,7 +3499,7 @@ static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
Info.FFDiag(E, diag::note_constexpr_use_uninit_reference);
return false;
}
- Result = &Info.CurrentCall->createConstexprUnknownAPValues(VD, Base);
+ Result = nullptr;
}
return true;
};
@@ -3552,7 +3542,7 @@ static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
// ... its lifetime began within the evaluation of E;
if (isa<ParmVarDecl>(VD)) {
if (AllowConstexprUnknown) {
- Result = &Info.CurrentCall->createConstexprUnknownAPValues(VD, Base);
+ Result = nullptr;
return true;
}
@@ -3659,12 +3649,8 @@ static bool evaluateVarDeclInit(EvalInfo &Info, const Expr *E,
Result = VD->getEvaluatedValue();
- if (!Result) {
- if (AllowConstexprUnknown)
- Result = &Info.CurrentCall->createConstexprUnknownAPValues(VD, Base);
- else
- return false;
- }
+ if (!Result && !AllowConstexprUnknown)
+ return false;
return CheckUninitReference(/*IsLocalVariable=*/false);
}
@@ -3947,11 +3933,6 @@ findSubobject(EvalInfo &Info, const Expr *E, const CompleteObject &Obj,
const FieldDecl *LastField = nullptr;
const FieldDecl *VolatileField = nullptr;
- // C++23 [expr.const]p8 If we have an unknown reference or pointers and it
- // does not have a value then bail out.
- if (O->allowConstexprUnknown() && !O->hasValue())
- return false;
-
// Walk the designator's path to find the subobject.
for (unsigned I = 0, N = Sub.Entries.size(); /**/; ++I) {
// Reading an indeterminate value is undefined, but assigning over one is OK.
@@ -4491,6 +4472,15 @@ static CompleteObject findCompleteObject(EvalInfo &Info, const Expr *E,
if (!evaluateVarDeclInit(Info, E, VD, Frame, LVal.getLValueVersion(), BaseVal))
return CompleteObject();
+ // If evaluateVarDeclInit sees a constexpr-unknown variable, it returns
+ // a null BaseVal. Any constexpr-unknown variable seen here is an error:
+ // we can't access a constexpr-unknown object.
+ if (!BaseVal) {
+ Info.FFDiag(E, diag::note_constexpr_access_unknown_variable, 1)
+ << AK << VD;
+ Info.Note(VD->getLocation(), diag::note_declared_at);
+ return CompleteObject();
+ }
} else if (DynamicAllocLValue DA = LVal.Base.dyn_cast<DynamicAllocLValue>()) {
std::optional<DynAlloc *> Alloc = Info.lookupDynamicAlloc(DA);
if (!Alloc) {
@@ -6057,15 +6047,6 @@ struct CheckDynamicTypeHandler {
/// dynamic type.
static bool checkDynamicType(EvalInfo &Info, const Expr *E, const LValue &This,
AccessKinds AK, bool Polymorphic) {
- // We are not allowed to invoke a virtual function whose dynamic type
- // is constexpr-unknown, so stop early and let this fail later on if we
- // attempt to do so.
- // C++23 [expr.const]p5.6
- // an invocation of a virtual function ([class.virtual]) for an object whose
- // dynamic type is constexpr-unknown;
- if (This.allowConstexprUnknown())
- return true;
-
if (This.Designator.Invalid)
return false;
@@ -6139,9 +6120,7 @@ static std::optional<DynamicType> ComputeDynamicType(EvalInfo &Info,
// meaningful dynamic type. (We consider objects of non-class type to have no
// dynamic type.)
if (!checkDynamicType(Info, E, This, AK,
- (AK == AK_TypeId
- ? (E->getType()->isReferenceType() ? true : false)
- : true)))
+ AK != AK_TypeId || This.AllowConstexprUnknown))
return std::nullopt;
if (This.Designator.Invalid)
@@ -9063,6 +9042,12 @@ bool LValueExprEvaluator::VisitVarDecl(const Expr *E, const VarDecl *VD) {
if (!evaluateVarDeclInit(Info, E, VD, Frame, Version, V))
return false;
+ if (!V) {
+ Result.set(VD);
+ Result.AllowConstexprUnknown = true;
+ return true;
+ }
+
return Success(*V, E);
}
generated by cgit v1.1 at 2025-10-04 05:06:44 +0000