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[clang][bytecode] Pass initializer along in evaluateAsInitializer() #158056

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Merged
merged 1 commit into from
Sep 15, 2025
+30 −23
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[clang][bytecode] Pass initializer along in evaluateAsInitializer() #158056

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3 changes: 2 additions & 1 deletion clang/lib/AST/ByteCode/ByteCodeEmitter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -46,7 +46,8 @@ class ByteCodeEmitter {
/// Methods implemented by the compiler.
virtual bool visitFunc(const FunctionDecl *E) = 0;
virtual bool visitExpr(const Expr *E, bool DestroyToplevelScope) = 0;
virtual bool visitDeclAndReturn(const VarDecl *E, bool ConstantContext) = 0;
virtual bool visitDeclAndReturn(const VarDecl *VD, const Expr *Init,
bool ConstantContext) = 0;
virtual bool visit(const Expr *E) = 0;
virtual bool emitBool(bool V, const Expr *E) = 0;

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21 changes: 10 additions & 11 deletions clang/lib/AST/ByteCode/Compiler.cpp
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Expand Up @@ -4714,7 +4714,8 @@ template <class Emitter>
VarCreationState Compiler<Emitter>::visitDecl(const VarDecl *VD,
bool IsConstexprUnknown) {

auto R = this->visitVarDecl(VD, /*Toplevel=*/true, IsConstexprUnknown);
auto R = this->visitVarDecl(VD, VD->getInit(), /*Toplevel=*/true,
IsConstexprUnknown);

if (R.notCreated())
return R;
Expand All @@ -4740,22 +4741,20 @@ VarCreationState Compiler<Emitter>::visitDecl(const VarDecl *VD,
/// We get here from evaluateAsInitializer().
/// We need to evaluate the initializer and return its value.
template <class Emitter>
bool Compiler<Emitter>::visitDeclAndReturn(const VarDecl *VD,
bool Compiler<Emitter>::visitDeclAndReturn(const VarDecl *VD, const Expr *Init,
bool ConstantContext) {

// We only create variables if we're evaluating in a constant context.
// Otherwise, just evaluate the initializer and return it.
if (!ConstantContext) {
DeclScope<Emitter> LS(this, VD);
const Expr *Init = VD->getInit();
if (!this->visit(Init))
return false;
return this->emitRet(classify(Init).value_or(PT_Ptr), VD) &&
LS.destroyLocals() && this->emitCheckAllocations(VD);
}

LocalScope<Emitter> VDScope(this, VD);
if (!this->visitVarDecl(VD, /*Toplevel=*/true))
if (!this->visitVarDecl(VD, Init, /*Toplevel=*/true))
return false;

OptPrimType VarT = classify(VD->getType());
Expand Down Expand Up @@ -4802,9 +4801,9 @@ bool Compiler<Emitter>::visitDeclAndReturn(const VarDecl *VD,
}

template <class Emitter>
VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
bool Toplevel,
bool IsConstexprUnknown) {
VarCreationState
Compiler<Emitter>::visitVarDecl(const VarDecl *VD, const Expr *Init,
bool Toplevel, bool IsConstexprUnknown) {
// We don't know what to do with these, so just return false.
if (VD->getType().isNull())
return false;
Expand All @@ -4814,7 +4813,6 @@ VarCreationState Compiler<Emitter>::visitVarDecl(const VarDecl *VD,
if (!this->isActive())
return VarCreationState::NotCreated();

const Expr *Init = VD->getInit();
OptPrimType VarT = classify(VD->getType());

if (Init && Init->isValueDependent())
Expand Down Expand Up @@ -5488,7 +5486,8 @@ template <class Emitter>
bool Compiler<Emitter>::maybeEmitDeferredVarInit(const VarDecl *VD) {
if (auto *DD = dyn_cast_if_present<DecompositionDecl>(VD)) {
for (auto *BD : DD->flat_bindings())
if (auto *KD = BD->getHoldingVar(); KD && !this->visitVarDecl(KD))
if (auto *KD = BD->getHoldingVar();
KD && !this->visitVarDecl(KD, KD->getInit()))
return false;
}
return true;
Expand Down Expand Up @@ -5552,7 +5551,7 @@ bool Compiler<Emitter>::visitDeclStmt(const DeclStmt *DS,
const auto *VD = dyn_cast<VarDecl>(D);
if (!VD)
return false;
if (!this->visitVarDecl(VD))
if (!this->visitVarDecl(VD, VD->getInit()))
return false;

// Register decomposition decl holding vars.
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6 changes: 4 additions & 2 deletions clang/lib/AST/ByteCode/Compiler.h
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Expand Up @@ -251,7 +251,8 @@ class Compiler : public ConstStmtVisitor<Compiler<Emitter>, bool>,
bool visitExpr(const Expr *E, bool DestroyToplevelScope) override;
bool visitFunc(const FunctionDecl *F) override;

bool visitDeclAndReturn(const VarDecl *VD, bool ConstantContext) override;
bool visitDeclAndReturn(const VarDecl *VD, const Expr *Init,
bool ConstantContext) override;

protected:
/// Emits scope cleanup instructions.
Expand Down Expand Up @@ -303,7 +304,8 @@ class Compiler : public ConstStmtVisitor<Compiler<Emitter>, bool>,
/// intact.
bool delegate(const Expr *E);
/// Creates and initializes a variable from the given decl.
VarCreationState visitVarDecl(const VarDecl *VD, bool Toplevel = false,
VarCreationState visitVarDecl(const VarDecl *VD, const Expr *Init,
bool Toplevel = false,
bool IsConstexprUnknown = false);
VarCreationState visitDecl(const VarDecl *VD,
bool IsConstexprUnknown = false);
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4 changes: 2 additions & 2 deletions clang/lib/AST/ByteCode/Context.cpp
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Expand Up @@ -126,7 +126,7 @@ bool Context::evaluate(State &Parent, const Expr *E, APValue &Result,
}

bool Context::evaluateAsInitializer(State &Parent, const VarDecl *VD,
APValue &Result) {
const Expr *Init, APValue &Result) {
++EvalID;
bool Recursing = !Stk.empty();
size_t StackSizeBefore = Stk.size();
Expand All @@ -135,7 +135,7 @@ bool Context::evaluateAsInitializer(State &Parent, const VarDecl *VD,
bool CheckGlobalInitialized =
shouldBeGloballyIndexed(VD) &&
(VD->getType()->isRecordType() || VD->getType()->isArrayType());
auto Res = C.interpretDecl(VD, CheckGlobalInitialized);
auto Res = C.interpretDecl(VD, Init, CheckGlobalInitialized);
if (Res.isInvalid()) {
C.cleanup();
Stk.clearTo(StackSizeBefore);
Expand Down
3 changes: 2 additions & 1 deletion clang/lib/AST/ByteCode/Context.h
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Expand Up @@ -59,7 +59,8 @@ class Context final {
ConstantExprKind Kind);

/// Evaluates a toplevel initializer.
bool evaluateAsInitializer(State &Parent, const VarDecl *VD, APValue &Result);
bool evaluateAsInitializer(State &Parent, const VarDecl *VD, const Expr *Init,
APValue &Result);

bool evaluateCharRange(State &Parent, const Expr *SizeExpr,
const Expr *PtrExpr, APValue &Result);
Expand Down
7 changes: 4 additions & 3 deletions clang/lib/AST/ByteCode/EvalEmitter.cpp
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Expand Up @@ -49,14 +49,15 @@ EvaluationResult EvalEmitter::interpretExpr(const Expr *E,
return std::move(this->EvalResult);
}

EvaluationResult EvalEmitter::interpretDecl(const VarDecl *VD,
EvaluationResult EvalEmitter::interpretDecl(const VarDecl *VD, const Expr *Init,
bool CheckFullyInitialized) {
this->CheckFullyInitialized = CheckFullyInitialized;
S.EvaluatingDecl = VD;
S.setEvalLocation(VD->getLocation());
EvalResult.setSource(VD);

if (const Expr *Init = VD->getAnyInitializer()) {
// FIXME: I think Init is never null.
if (Init) {
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You could add an assert and if it crashes, then this is incorrect, it does not prove it but it could show the negative and then you have a test case.

QualType T = VD->getType();
this->ConvertResultToRValue = !Init->isGLValue() && !T->isPointerType() &&
!T->isObjCObjectPointerType();
Expand All @@ -65,7 +66,7 @@ EvaluationResult EvalEmitter::interpretDecl(const VarDecl *VD,

EvalResult.setSource(VD);

if (!this->visitDeclAndReturn(VD, S.inConstantContext()))
if (!this->visitDeclAndReturn(VD, Init, S.inConstantContext()))
EvalResult.setInvalid();

S.EvaluatingDecl = nullptr;
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6 changes: 4 additions & 2 deletions clang/lib/AST/ByteCode/EvalEmitter.h
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Expand Up @@ -37,7 +37,8 @@ class EvalEmitter : public SourceMapper {
EvaluationResult interpretExpr(const Expr *E,
bool ConvertResultToRValue = false,
bool DestroyToplevelScope = false);
EvaluationResult interpretDecl(const VarDecl *VD, bool CheckFullyInitialized);
EvaluationResult interpretDecl(const VarDecl *VD, const Expr *Init,
bool CheckFullyInitialized);
/// Interpret the given Expr to a Pointer.
EvaluationResult interpretAsPointer(const Expr *E, PtrCallback PtrCB);
/// Interpret the given expression as if it was in the body of the given
Expand All @@ -59,7 +60,8 @@ class EvalEmitter : public SourceMapper {

/// Methods implemented by the compiler.
virtual bool visitExpr(const Expr *E, bool DestroyToplevelScope) = 0;
virtual bool visitDeclAndReturn(const VarDecl *VD, bool ConstantContext) = 0;
virtual bool visitDeclAndReturn(const VarDecl *VD, const Expr *Init,
bool ConstantContext) = 0;
virtual bool visitFunc(const FunctionDecl *F) = 0;
virtual bool visit(const Expr *E) = 0;
virtual bool emitBool(bool V, const Expr *E) = 0;
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2 changes: 1 addition & 1 deletion clang/lib/AST/ExprConstant.cpp
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Expand Up @@ -17755,7 +17755,7 @@ bool Expr::EvaluateAsInitializer(APValue &Value, const ASTContext &Ctx,

if (Info.EnableNewConstInterp) {
auto &InterpCtx = const_cast<ASTContext &>(Ctx).getInterpContext();
if (!InterpCtx.evaluateAsInitializer(Info, VD, Value))
if (!InterpCtx.evaluateAsInitializer(Info, VD, this, Value))
return false;

return CheckConstantExpression(Info, DeclLoc, DeclTy, Value,
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1 change: 1 addition & 0 deletions clang/test/Modules/added-visible-decls.cppm
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Expand Up @@ -5,6 +5,7 @@
// RUN: %clang_cc1 -std=c++20 %t/b.cppm -emit-reduced-module-interface -o %t/b.pcm -fprebuilt-module-path=%t
// RUN: %clang_cc1 -std=c++20 %t/c.cppm -emit-reduced-module-interface -o %t/c.pcm -fprebuilt-module-path=%t
// RUN: %clang_cc1 -std=c++20 %t/d.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
// RUN: %clang_cc1 -std=c++20 %t/d.cpp -fprebuilt-module-path=%t -fsyntax-only -verify -fexperimental-new-constant-interpreter
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@ChuanqiXu9 Is it okay to add this line?


//--- a.h
template <typename T>
Expand Down