[clang][bytecode] Avoid copying APValue into EvaluationResult (#155757)

Move the `APValue` into `EvaluationResult` instead. For a large primitive array (`#embed` of the sqlite3 amalgamation), this improves compile times by around 25%.

Author: tbaederr

clang/lib/AST/ByteCode/EvalEmitter.cpp

@@ -184,7 +184,7 @@ template <PrimType OpType> bool EvalEmitter::emitRet(const SourceInfo &Info) {
  return true;
 
  using T = typename PrimConv<OpType>::T;
- EvalResult.setValue(S.Stk.pop<T>().toAPValue(Ctx.getASTContext()));
+ EvalResult.takeValue(S.Stk.pop<T>().toAPValue(Ctx.getASTContext()));
  return true;
 }
 
@@ -195,7 +195,7 @@ template <> bool EvalEmitter::emitRet<PT_Ptr>(const SourceInfo &Info) {
  const Pointer &Ptr = S.Stk.pop<Pointer>();
 
  if (Ptr.isFunctionPointer()) {
- EvalResult.setValue(Ptr.toAPValue(Ctx.getASTContext()));
+ EvalResult.takeValue(Ptr.toAPValue(Ctx.getASTContext()));
  return true;
  }
 
@@ -224,7 +224,7 @@ template <> bool EvalEmitter::emitRet<PT_Ptr>(const SourceInfo &Info) {
 
  if (std::optional<APValue> V =
  Ptr.toRValue(Ctx, EvalResult.getSourceType())) {
- EvalResult.setValue(*V);
+ EvalResult.takeValue(std::move(*V));
  } else {
  return false;
  }
@@ -233,14 +233,14 @@ template <> bool EvalEmitter::emitRet<PT_Ptr>(const SourceInfo &Info) {
  // the result, even if the pointer is dead.
  // This will later be diagnosed by CheckLValueConstantExpression.
  if (Ptr.isBlockPointer() && !Ptr.block()->isStatic()) {
- EvalResult.setValue(Ptr.toAPValue(Ctx.getASTContext()));
+ EvalResult.takeValue(Ptr.toAPValue(Ctx.getASTContext()));
  return true;
  }
 
  if (!Ptr.isLive() && !Ptr.isTemporary())
  return false;
 
- EvalResult.setValue(Ptr.toAPValue(Ctx.getASTContext()));
+ EvalResult.takeValue(Ptr.toAPValue(Ctx.getASTContext()));
  }
 
  return true;
@@ -261,7 +261,7 @@ bool EvalEmitter::emitRetValue(const SourceInfo &Info) {
 
  if (std::optional<APValue> APV =
  Ptr.toRValue(S.getASTContext(), EvalResult.getSourceType())) {
- EvalResult.setValue(*APV);
+ EvalResult.takeValue(std::move(*APV));
  return true;
  }
 

clang/lib/AST/ByteCode/EvaluationResult.h

@@ -55,7 +55,7 @@ class EvaluationResult final {
 
  void setSource(DeclTy D) { Source = D; }
 
- void setValue(const APValue &V) {
+ void takeValue(APValue &&V) {
  // V could still be an LValue.
  assert(empty());
  Value = std::move(V);