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[clang][bytecode] Use SmallVector for Function::Code #151821

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Merged
tbaederr merged 2 commits into from
Aug 4, 2025
Merged

[clang][bytecode] Use SmallVector for Function::Code #151821

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f021cf0
[clang][bytecode] Use SmallVector for Function::Code
tbaederr Aug 2, 2025
1306a74
Use SmallVectorImpl parameters
tbaederr Aug 2, 2025
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24 changes: 12 additions & 12 deletions clang/lib/AST/ByteCode/ByteCodeEmitter.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -135,8 +135,8 @@ int32_t ByteCodeEmitter::getOffset(LabelTy Label) {
/// Helper to write bytecode and bail out if 32-bit offsets become invalid.
/// Pointers will be automatically marshalled as 32-bit IDs.
template <typename T>
static void emit(Program &P, std::vector<std::byte> &Code, const T &Val,
bool &Success) {
static void emit(Program &P, llvm::SmallVectorImpl<std::byte> &Code,
const T &Val, bool &Success) {
size_t ValPos = Code.size();
size_t Size;

Expand All @@ -153,7 +153,7 @@ static void emit(Program &P, std::vector<std::byte> &Code, const T &Val,
// Access must be aligned!
assert(aligned(ValPos));
assert(aligned(ValPos + Size));
Code.resize(ValPos + Size);
Code.resize_for_overwrite(ValPos + Size);

if constexpr (!std::is_pointer_v<T>) {
new (Code.data() + ValPos) T(Val);
Expand All @@ -166,7 +166,7 @@ static void emit(Program &P, std::vector<std::byte> &Code, const T &Val,
/// Emits a serializable value. These usually (potentially) contain
/// heap-allocated memory and aren't trivially copyable.
template <typename T>
static void emitSerialized(std::vector<std::byte> &Code, const T &Val,
static void emitSerialized(llvm::SmallVectorImpl<std::byte> &Code, const T &Val,
bool &Success) {
size_t ValPos = Code.size();
size_t Size = align(Val.bytesToSerialize());
Expand All @@ -179,32 +179,32 @@ static void emitSerialized(std::vector<std::byte> &Code, const T &Val,
// Access must be aligned!
assert(aligned(ValPos));
assert(aligned(ValPos + Size));
Code.resize(ValPos + Size);
Code.resize_for_overwrite(ValPos + Size);

Val.serialize(Code.data() + ValPos);
}

template <>
void emit(Program &P, std::vector<std::byte> &Code, const Floating &Val,
bool &Success) {
void emit(Program &P, llvm::SmallVectorImpl<std::byte> &Code,
const Floating &Val, bool &Success) {
emitSerialized(Code, Val, Success);
}

template <>
void emit(Program &P, std::vector<std::byte> &Code,
void emit(Program &P, llvm::SmallVectorImpl<std::byte> &Code,
const IntegralAP<false> &Val, bool &Success) {
emitSerialized(Code, Val, Success);
}

template <>
void emit(Program &P, std::vector<std::byte> &Code, const IntegralAP<true> &Val,
bool &Success) {
void emit(Program &P, llvm::SmallVectorImpl<std::byte> &Code,
const IntegralAP<true> &Val, bool &Success) {
emitSerialized(Code, Val, Success);
}

template <>
void emit(Program &P, std::vector<std::byte> &Code, const FixedPoint &Val,
bool &Success) {
void emit(Program &P, llvm::SmallVectorImpl<std::byte> &Code,
const FixedPoint &Val, bool &Success) {
emitSerialized(Code, Val, Success);
}

Expand Down
2 changes: 1 addition & 1 deletion clang/lib/AST/ByteCode/ByteCodeEmitter.h
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Original file line number Diff line number Diff line change
Expand Up @@ -88,7 +88,7 @@ class ByteCodeEmitter {
/// Location of label relocations.
llvm::DenseMap<LabelTy, llvm::SmallVector<unsigned, 5>> LabelRelocs;
/// Program code.
std::vector<std::byte> Code;
llvm::SmallVector<std::byte> Code;
/// Opcode to expression mapping.
SourceMap SrcMap;

Expand Down
8 changes: 4 additions & 4 deletions clang/lib/AST/ByteCode/Context.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -44,12 +44,12 @@ bool Context::isPotentialConstantExpr(State &Parent, const FunctionDecl *FD) {
Compiler<ByteCodeEmitter>(*this, *P).compileFunc(
FD, const_cast<Function *>(Func));

++EvalID;
// And run it.
if (!Run(Parent, Func))
if (!Func->isValid())
return false;

return Func->isValid();
++EvalID;
// And run it.
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@shafik shafik Aug 2, 2025 •
edited
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I wonder how useful this inline comments are, I feel like that might be better and added to the comment on the declaration of isPotentialConstantExpr something like

"Check if the function is a potential constant expression by compiling the function and running it."

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@tbaederr tbaederr Aug 4, 2025

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I don't really care either way but this comment isn't new from this patch, just moved down a bit.

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@shafik shafik Aug 4, 2025

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This is a drive by nit but since you in this area already it feels like a worthwhile fix.

return Run(Parent, Func);
}

void Context::isPotentialConstantExprUnevaluated(State &Parent, const Expr *E,
Expand Down
4 changes: 2 additions & 2 deletions clang/lib/AST/ByteCode/Function.h
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Expand Up @@ -236,7 +236,7 @@ class Function final {
bool HasRVO, bool IsLambdaStaticInvoker);

/// Sets the code of a function.
void setCode(unsigned NewFrameSize, std::vector<std::byte> &&NewCode,
void setCode(unsigned NewFrameSize, llvm::SmallVector<std::byte> &&NewCode,
SourceMap &&NewSrcMap, llvm::SmallVector<Scope, 2> &&NewScopes,
bool NewHasBody) {
FrameSize = NewFrameSize;
Expand Down Expand Up @@ -266,7 +266,7 @@ class Function final {
/// Size of the argument stack.
unsigned ArgSize;
/// Program code.
std::vector<std::byte> Code;
llvm::SmallVector<std::byte> Code;
/// Opcode-to-expression mapping.
SourceMap SrcMap;
/// List of block descriptors.
Expand Down