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[clang][bytecode] Create implicit variables for wider base types #156658

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Merged
tbaederr merged 1 commit into from
Sep 4, 2025
Merged

[clang][bytecode] Create implicit variables for wider base types #156658

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41 changes: 27 additions & 14 deletions clang/lib/AST/ByteCode/Compiler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4191,6 +4191,31 @@ template <class Emitter> bool Compiler<Emitter>::delegate(const Expr *E) {
return this->Visit(E);
}

static const Expr *stripCheckedDerivedToBaseCasts(const Expr *E) {
if (const auto *PE = dyn_cast<ParenExpr>(E))
return stripCheckedDerivedToBaseCasts(PE->getSubExpr());

if (const auto *CE = dyn_cast<CastExpr>(E);
CE &&
(CE->getCastKind() == CK_DerivedToBase || CE->getCastKind() == CK_NoOp))
return stripCheckedDerivedToBaseCasts(CE->getSubExpr());

return E;
}

static const Expr *stripDerivedToBaseCasts(const Expr *E) {
if (const auto *PE = dyn_cast<ParenExpr>(E))
return stripDerivedToBaseCasts(PE->getSubExpr());

if (const auto *CE = dyn_cast<CastExpr>(E);
CE && (CE->getCastKind() == CK_DerivedToBase ||
CE->getCastKind() == CK_UncheckedDerivedToBase ||
CE->getCastKind() == CK_NoOp))
return stripDerivedToBaseCasts(CE->getSubExpr());

return E;
}

template <class Emitter> bool Compiler<Emitter>::visit(const Expr *E) {
if (E->getType().isNull())
return false;
Expand All @@ -4200,7 +4225,7 @@ template <class Emitter> bool Compiler<Emitter>::visit(const Expr *E) {

// Create local variable to hold the return value.
if (!E->isGLValue() && !canClassify(E->getType())) {
UnsignedOrNone LocalIndex = allocateLocal(E);
UnsignedOrNone LocalIndex = allocateLocal(stripDerivedToBaseCasts(E));
if (!LocalIndex)
return false;

Expand Down Expand Up @@ -5078,18 +5103,6 @@ bool Compiler<Emitter>::VisitBuiltinCallExpr(const CallExpr *E,
return true;
}

static const Expr *stripDerivedToBaseCasts(const Expr *E) {
if (const auto *PE = dyn_cast<ParenExpr>(E))
return stripDerivedToBaseCasts(PE->getSubExpr());

if (const auto *CE = dyn_cast<CastExpr>(E);
CE &&
(CE->getCastKind() == CK_DerivedToBase || CE->getCastKind() == CK_NoOp))
return stripDerivedToBaseCasts(CE->getSubExpr());

return E;
}

template <class Emitter>
bool Compiler<Emitter>::VisitCallExpr(const CallExpr *E) {
const FunctionDecl *FuncDecl = E->getDirectCallee();
Expand Down Expand Up @@ -5194,7 +5207,7 @@ bool Compiler<Emitter>::VisitCallExpr(const CallExpr *E) {
const auto *InstancePtr = MC->getImplicitObjectArgument();
if (isa_and_nonnull<CXXDestructorDecl>(CompilingFunction) ||
isa_and_nonnull<CXXConstructorDecl>(CompilingFunction)) {
const auto *Stripped = stripDerivedToBaseCasts(InstancePtr);
const auto *Stripped = stripCheckedDerivedToBaseCasts(InstancePtr);
if (isa<CXXThisExpr>(Stripped)) {
FuncDecl =
cast<CXXMethodDecl>(FuncDecl)->getCorrespondingMethodInClass(
Expand Down
11 changes: 11 additions & 0 deletions clang/test/AST/ByteCode/cxx03.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -29,3 +29,14 @@ void LambdaAccessingADummy() {
int d;
int a9[1] = {[d = 0] = 1}; // both-error {{is not an integral constant expression}}
}

const int p = 10;
struct B {
int a;
void *p;
};
struct B2 : B {
void *q;
};
_Static_assert(&(B2().a) == &p, ""); // both-error {{taking the address of a temporary object of type 'int'}} \
// both-error {{not an integral constant expression}}