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[clang][bytecode] Propagate IsVolatile bit to subobjects #137293

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Apr 25, 2025
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[clang][bytecode] Propagate IsVolatile bit to subobjects #137293

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17 changes: 7 additions & 10 deletions clang/lib/AST/ByteCode/Compiler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -364,8 +364,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
Desc = P.createDescriptor(SubExpr, *T);
else
Desc = P.createDescriptor(SubExpr, PointeeType.getTypePtr(),
std::nullopt, true, false,
/*IsMutable=*/false, nullptr);
std::nullopt, /*IsConst=*/true);
}

uint64_t Val = Ctx.getASTContext().getTargetNullPointerValue(CE->getType());
Expand Down Expand Up @@ -417,8 +416,7 @@ bool Compiler<Emitter>::VisitCastExpr(const CastExpr *CE) {
Desc = nullptr;
else
Desc = P.createDescriptor(CE, PtrType->getPointeeType().getTypePtr(),
Descriptor::InlineDescMD, true, false,
/*IsMutable=*/false, nullptr);
Descriptor::InlineDescMD, /*IsConst=*/true);

if (!this->emitGetIntPtr(T, Desc, CE))
return false;
Expand Down Expand Up @@ -3400,14 +3398,13 @@ bool Compiler<Emitter>::VisitCXXNewExpr(const CXXNewExpr *E) {
Desc = nullptr; // We're not going to use it in this case.
else
Desc = P.createDescriptor(E, *ElemT, /*SourceTy=*/nullptr,
Descriptor::InlineDescMD,
/*IsConst=*/false, /*IsTemporary=*/false,
/*IsMutable=*/false);
Descriptor::InlineDescMD);
} else {
Desc = P.createDescriptor(
E, ElementType.getTypePtr(),
E->isArray() ? std::nullopt : Descriptor::InlineDescMD,
/*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false, Init);
/*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false,
/*IsVolatile=*/false, Init);
}
}

Expand Down Expand Up @@ -4355,7 +4352,7 @@ Compiler<Emitter>::allocateLocal(DeclTy &&Src, QualType Ty,

Descriptor *D = P.createDescriptor(
Src, Ty.getTypePtr(), Descriptor::InlineDescMD, Ty.isConstQualified(),
IsTemporary, /*IsMutable=*/false, Init);
IsTemporary, /*IsMutable=*/false, /*IsVolatile=*/false, Init);
if (!D)
return std::nullopt;
D->IsConstexprUnknown = IsConstexprUnknown;
Expand All @@ -4377,7 +4374,7 @@ std::optional<unsigned> Compiler<Emitter>::allocateTemporary(const Expr *E) {

Descriptor *D = P.createDescriptor(
E, Ty.getTypePtr(), Descriptor::InlineDescMD, Ty.isConstQualified(),
/*IsTemporary=*/true, /*IsMutable=*/false, /*Init=*/nullptr);
/*IsTemporary=*/true);

if (!D)
return std::nullopt;
Expand Down
60 changes: 34 additions & 26 deletions clang/lib/AST/ByteCode/Descriptor.cpp
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Expand Up @@ -22,7 +22,7 @@ using namespace clang;
using namespace clang::interp;

template <typename T>
static void ctorTy(Block *, std::byte *Ptr, bool, bool, bool, bool,
static void ctorTy(Block *, std::byte *Ptr, bool, bool, bool, bool, bool,
const Descriptor *) {
new (Ptr) T();
}
Expand All @@ -41,7 +41,7 @@ static void moveTy(Block *, std::byte *Src, std::byte *Dst,
}

template <typename T>
static void ctorArrayTy(Block *, std::byte *Ptr, bool, bool, bool, bool,
static void ctorArrayTy(Block *, std::byte *Ptr, bool, bool, bool, bool, bool,
const Descriptor *D) {
new (Ptr) InitMapPtr(std::nullopt);

Expand Down Expand Up @@ -82,8 +82,8 @@ static void moveArrayTy(Block *, std::byte *Src, std::byte *Dst,
}

static void ctorArrayDesc(Block *B, std::byte *Ptr, bool IsConst,
bool IsMutable, bool IsActive, bool InUnion,
const Descriptor *D) {
bool IsMutable, bool IsVolatile, bool IsActive,
bool InUnion, const Descriptor *D) {
const unsigned NumElems = D->getNumElems();
const unsigned ElemSize =
D->ElemDesc->getAllocSize() + sizeof(InlineDescriptor);
Expand All @@ -104,9 +104,10 @@ static void ctorArrayDesc(Block *B, std::byte *Ptr, bool IsConst,
Desc->IsFieldMutable = IsMutable || D->IsMutable;
Desc->InUnion = InUnion;
Desc->IsArrayElement = true;
Desc->IsVolatile = IsVolatile;

if (auto Fn = D->ElemDesc->CtorFn)
Fn(B, ElemLoc, Desc->IsConst, Desc->IsFieldMutable, IsActive,
Fn(B, ElemLoc, Desc->IsConst, Desc->IsFieldMutable, IsVolatile, IsActive,
Desc->InUnion || SD->isUnion(), D->ElemDesc);
}
}
Expand Down Expand Up @@ -149,8 +150,8 @@ static void moveArrayDesc(Block *B, std::byte *Src, std::byte *Dst,
}

static void initField(Block *B, std::byte *Ptr, bool IsConst, bool IsMutable,
bool IsActive, bool IsUnionField, bool InUnion,
const Descriptor *D, unsigned FieldOffset) {
bool IsVolatile, bool IsActive, bool IsUnionField,
bool InUnion, const Descriptor *D, unsigned FieldOffset) {
auto *Desc = reinterpret_cast<InlineDescriptor *>(Ptr + FieldOffset) - 1;
Desc->Offset = FieldOffset;
Desc->Desc = D;
Expand All @@ -160,15 +161,17 @@ static void initField(Block *B, std::byte *Ptr, bool IsConst, bool IsMutable,
Desc->InUnion = InUnion;
Desc->IsConst = IsConst || D->IsConst;
Desc->IsFieldMutable = IsMutable || D->IsMutable;
Desc->IsVolatile = IsVolatile || D->IsVolatile;

if (auto Fn = D->CtorFn)
Fn(B, Ptr + FieldOffset, Desc->IsConst, Desc->IsFieldMutable,
Desc->IsActive, InUnion || D->isUnion(), D);
Desc->IsVolatile, Desc->IsActive, InUnion || D->isUnion(), D);
}

static void initBase(Block *B, std::byte *Ptr, bool IsConst, bool IsMutable,
bool IsActive, bool InUnion, const Descriptor *D,
unsigned FieldOffset, bool IsVirtualBase) {
bool IsVolatile, bool IsActive, bool InUnion,
const Descriptor *D, unsigned FieldOffset,
bool IsVirtualBase) {
assert(D);
assert(D->ElemRecord);
assert(!D->ElemRecord->isUnion()); // Unions cannot be base classes.
Expand All @@ -183,28 +186,32 @@ static void initBase(Block *B, std::byte *Ptr, bool IsConst, bool IsMutable,
Desc->IsConst = IsConst || D->IsConst;
Desc->IsFieldMutable = IsMutable || D->IsMutable;
Desc->InUnion = InUnion;
Desc->IsVolatile = false;

for (const auto &V : D->ElemRecord->bases())
initBase(B, Ptr + FieldOffset, IsConst, IsMutable, IsActive, InUnion,
V.Desc, V.Offset, false);
initBase(B, Ptr + FieldOffset, IsConst, IsMutable, IsVolatile, IsActive,
InUnion, V.Desc, V.Offset, false);
for (const auto &F : D->ElemRecord->fields())
initField(B, Ptr + FieldOffset, IsConst, IsMutable, IsActive, InUnion,
InUnion, F.Desc, F.Offset);
initField(B, Ptr + FieldOffset, IsConst, IsMutable, IsVolatile, IsActive,
InUnion, InUnion, F.Desc, F.Offset);
}

static void ctorRecord(Block *B, std::byte *Ptr, bool IsConst, bool IsMutable,
bool IsActive, bool InUnion, const Descriptor *D) {
bool IsVolatile, bool IsActive, bool InUnion,
const Descriptor *D) {
for (const auto &V : D->ElemRecord->bases())
initBase(B, Ptr, IsConst, IsMutable, IsActive, InUnion, V.Desc, V.Offset,
false);
initBase(B, Ptr, IsConst, IsMutable, IsVolatile, IsActive, InUnion, V.Desc,
V.Offset,
/*IsVirtualBase=*/false);
for (const auto &F : D->ElemRecord->fields()) {
bool IsUnionField = D->isUnion();
initField(B, Ptr, IsConst, IsMutable, IsActive, IsUnionField,
initField(B, Ptr, IsConst, IsMutable, IsVolatile, IsActive, IsUnionField,
InUnion || IsUnionField, F.Desc, F.Offset);
}
for (const auto &V : D->ElemRecord->virtual_bases())
initBase(B, Ptr, IsConst, IsMutable, IsActive, InUnion, V.Desc, V.Offset,
true);
initBase(B, Ptr, IsConst, IsMutable, IsVolatile, IsActive, InUnion, V.Desc,
V.Offset,
/*IsVirtualBase=*/true);
}

static void destroyField(Block *B, std::byte *Ptr, const Descriptor *D,
Expand Down Expand Up @@ -332,12 +339,12 @@ static BlockMoveFn getMoveArrayPrim(PrimType Type) {
/// Primitives.
Descriptor::Descriptor(const DeclTy &D, const Type *SourceTy, PrimType Type,
MetadataSize MD, bool IsConst, bool IsTemporary,
bool IsMutable)
bool IsMutable, bool IsVolatile)
: Source(D), SourceType(SourceTy), ElemSize(primSize(Type)), Size(ElemSize),
MDSize(MD.value_or(0)), AllocSize(align(Size + MDSize)), PrimT(Type),
IsConst(IsConst), IsMutable(IsMutable), IsTemporary(IsTemporary),
CtorFn(getCtorPrim(Type)), DtorFn(getDtorPrim(Type)),
MoveFn(getMovePrim(Type)) {
IsVolatile(IsVolatile), CtorFn(getCtorPrim(Type)),
DtorFn(getDtorPrim(Type)), MoveFn(getMovePrim(Type)) {
assert(AllocSize >= Size);
assert(Source && "Missing source");
}
Expand Down Expand Up @@ -396,12 +403,13 @@ Descriptor::Descriptor(const DeclTy &D, const Descriptor *Elem, MetadataSize MD,

/// Composite records.
Descriptor::Descriptor(const DeclTy &D, const Record *R, MetadataSize MD,
bool IsConst, bool IsTemporary, bool IsMutable)
bool IsConst, bool IsTemporary, bool IsMutable,
bool IsVolatile)
: Source(D), ElemSize(std::max<size_t>(alignof(void *), R->getFullSize())),
Size(ElemSize), MDSize(MD.value_or(0)), AllocSize(Size + MDSize),
ElemRecord(R), IsConst(IsConst), IsMutable(IsMutable),
IsTemporary(IsTemporary), CtorFn(ctorRecord), DtorFn(dtorRecord),
MoveFn(moveRecord) {
IsTemporary(IsTemporary), IsVolatile(IsVolatile), CtorFn(ctorRecord),
DtorFn(dtorRecord), MoveFn(moveRecord) {
assert(Source && "Missing source");
}

Expand Down
15 changes: 10 additions & 5 deletions clang/lib/AST/ByteCode/Descriptor.h
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Expand Up @@ -33,8 +33,8 @@ using InitMapPtr = std::optional<std::pair<bool, std::shared_ptr<InitMap>>>;
/// inline descriptors of all fields and array elements. It also initializes
/// all the fields which contain non-trivial types.
using BlockCtorFn = void (*)(Block *Storage, std::byte *FieldPtr, bool IsConst,
bool IsMutable, bool IsActive, bool InUnion,
const Descriptor *FieldDesc);
bool IsMutable, bool IsVolatile, bool IsActive,
bool InUnion, const Descriptor *FieldDesc);

/// Invoked when a block is destroyed. Invokes the destructors of all
/// non-trivial nested fields of arrays and records.
Expand Down Expand Up @@ -104,6 +104,8 @@ struct InlineDescriptor {
/// Flag indicating if the field is an element of a composite array.
LLVM_PREFERRED_TYPE(bool)
unsigned IsArrayElement : 1;
LLVM_PREFERRED_TYPE(bool)
unsigned IsVolatile : 1;

Lifetime LifeState;

Expand All @@ -112,7 +114,8 @@ struct InlineDescriptor {
InlineDescriptor(const Descriptor *D)
: Offset(sizeof(InlineDescriptor)), IsConst(false), IsInitialized(false),
IsBase(false), IsActive(false), IsFieldMutable(false),
IsArrayElement(false), LifeState(Lifetime::Started), Desc(D) {}
IsArrayElement(false), IsVolatile(false), LifeState(Lifetime::Started),
Desc(D) {}

void dump() const { dump(llvm::errs()); }
void dump(llvm::raw_ostream &OS) const;
Expand Down Expand Up @@ -164,6 +167,7 @@ struct Descriptor final {
const bool IsMutable = false;
/// Flag indicating if the block is a temporary.
const bool IsTemporary = false;
const bool IsVolatile = false;
/// Flag indicating if the block is an array.
const bool IsArray = false;
/// Flag indicating if this is a dummy descriptor.
Expand All @@ -177,7 +181,8 @@ struct Descriptor final {

/// Allocates a descriptor for a primitive.
Descriptor(const DeclTy &D, const Type *SourceTy, PrimType Type,
MetadataSize MD, bool IsConst, bool IsTemporary, bool IsMutable);
MetadataSize MD, bool IsConst, bool IsTemporary, bool IsMutable,
bool IsVolatile);

/// Allocates a descriptor for an array of primitives.
Descriptor(const DeclTy &D, PrimType Type, MetadataSize MD, size_t NumElems,
Expand All @@ -198,7 +203,7 @@ struct Descriptor final {

/// Allocates a descriptor for a record.
Descriptor(const DeclTy &D, const Record *R, MetadataSize MD, bool IsConst,
bool IsTemporary, bool IsMutable);
bool IsTemporary, bool IsMutable, bool IsVolatile);

/// Allocates a dummy descriptor.
Descriptor(const DeclTy &D, MetadataSize MD = std::nullopt);
Expand Down
1 change: 1 addition & 0 deletions clang/lib/AST/ByteCode/DynamicAllocator.cpp
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Expand Up @@ -84,6 +84,7 @@ Block *DynamicAllocator::allocate(const Descriptor *D, unsigned EvalID,
ID->IsFieldMutable = false;
ID->IsConst = false;
ID->IsInitialized = false;
ID->IsVolatile = false;

B->IsDynamic = true;

Expand Down
23 changes: 13 additions & 10 deletions clang/lib/AST/ByteCode/Interp.cpp
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Expand Up @@ -634,32 +634,35 @@ static bool CheckVolatile(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
AccessKinds AK) {
assert(Ptr.isLive());

// FIXME: This check here might be kinda expensive. Maybe it would be better
// to have another field in InlineDescriptor for this?
if (!Ptr.isBlockPointer())
return true;

QualType PtrType = Ptr.getType();
if (!PtrType.isVolatileQualified())
if (!Ptr.isVolatile())
return true;

if (!S.getLangOpts().CPlusPlus)
return Invalid(S, OpPC);

// The reason why Ptr is volatile might be further up the hierarchy.
// Find that pointer.
Pointer P = Ptr;
while (!P.isRoot()) {
if (P.getType().isVolatileQualified())
break;
P = P.getBase();
}

const NamedDecl *ND = nullptr;
int DiagKind;
SourceLocation Loc;
if (const auto *F = Ptr.getField()) {
if (const auto *F = P.getField()) {
DiagKind = 2;
Loc = F->getLocation();
ND = F;
} else if (auto *VD = Ptr.getFieldDesc()->asValueDecl()) {
} else if (auto *VD = P.getFieldDesc()->asValueDecl()) {
DiagKind = 1;
Loc = VD->getLocation();
ND = VD;
} else {
DiagKind = 0;
if (const auto *E = Ptr.getFieldDesc()->asExpr())
if (const auto *E = P.getFieldDesc()->asExpr())
Loc = E->getExprLoc();
}

Expand Down
1 change: 1 addition & 0 deletions clang/lib/AST/ByteCode/InterpBlock.h
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Expand Up @@ -114,6 +114,7 @@ class Block final {
std::memset(rawData(), 0, Desc->getAllocSize());
if (Desc->CtorFn) {
Desc->CtorFn(this, data(), Desc->IsConst, Desc->IsMutable,
Desc->IsVolatile,
/*isActive=*/true, /*InUnion=*/false, Desc);
}
IsInitialized = true;
Expand Down
8 changes: 3 additions & 5 deletions clang/lib/AST/ByteCode/InterpBuiltin.cpp
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Expand Up @@ -1595,11 +1595,9 @@ static bool interp__builtin_operator_new(InterpState &S, CodePtr OpPC,

assert(!ElemT);
// Structs etc.
const Descriptor *Desc = S.P.createDescriptor(
NewCall, ElemType.getTypePtr(),
IsArray ? std::nullopt : Descriptor::InlineDescMD,
/*IsConst=*/false, /*IsTemporary=*/false, /*IsMutable=*/false,
/*Init=*/nullptr);
const Descriptor *Desc =
S.P.createDescriptor(NewCall, ElemType.getTypePtr(),
IsArray ? std::nullopt : Descriptor::InlineDescMD);

if (IsArray) {
Block *B =
Expand Down
7 changes: 7 additions & 0 deletions clang/lib/AST/ByteCode/Pointer.h
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Expand Up @@ -577,6 +577,13 @@ class Pointer {
return isRoot() ? getDeclDesc()->IsConst : getInlineDesc()->IsConst;
}

/// Checks if an object or a subfield is volatile.
bool isVolatile() const {
if (!isBlockPointer())
return false;
return isRoot() ? getDeclDesc()->IsVolatile : getInlineDesc()->IsVolatile;
}

/// Returns the declaration ID.
std::optional<unsigned> getDeclID() const {
if (isBlockPointer()) {
Expand Down
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