llvm-project/clang/lib/AST/ByteCode/EvalEmitter.cpp
Timm Baeder 2d63faead4
[clang][bytecode][NFC] Remove PT_FnPtr (#135947)
We don't need this anymore since we don't return it from classify()
anymore.
2025-04-16 13:21:25 +02:00

312 lines
8.8 KiB
C++

//===--- EvalEmitter.cpp - Instruction emitter for the VM -------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "EvalEmitter.h"
#include "Context.h"
#include "IntegralAP.h"
#include "Interp.h"
#include "clang/AST/DeclCXX.h"
using namespace clang;
using namespace clang::interp;
EvalEmitter::EvalEmitter(Context &Ctx, Program &P, State &Parent,
InterpStack &Stk)
: Ctx(Ctx), P(P), S(Parent, P, Stk, Ctx, this), EvalResult(&Ctx) {}
EvalEmitter::~EvalEmitter() {
for (auto &[K, V] : Locals) {
Block *B = reinterpret_cast<Block *>(V.get());
if (B->isInitialized())
B->invokeDtor();
}
}
/// Clean up all our resources. This needs to done in failed evaluations before
/// we call InterpStack::clear(), because there might be a Pointer on the stack
/// pointing into a Block in the EvalEmitter.
void EvalEmitter::cleanup() { S.cleanup(); }
EvaluationResult EvalEmitter::interpretExpr(const Expr *E,
bool ConvertResultToRValue,
bool DestroyToplevelScope) {
S.setEvalLocation(E->getExprLoc());
this->ConvertResultToRValue = ConvertResultToRValue && !isa<ConstantExpr>(E);
this->CheckFullyInitialized = isa<ConstantExpr>(E);
EvalResult.setSource(E);
if (!this->visitExpr(E, DestroyToplevelScope)) {
// EvalResult may already have a result set, but something failed
// after that (e.g. evaluating destructors).
EvalResult.setInvalid();
}
return std::move(this->EvalResult);
}
EvaluationResult EvalEmitter::interpretDecl(const VarDecl *VD,
bool CheckFullyInitialized) {
this->CheckFullyInitialized = CheckFullyInitialized;
S.EvaluatingDecl = VD;
EvalResult.setSource(VD);
if (const Expr *Init = VD->getAnyInitializer()) {
QualType T = VD->getType();
this->ConvertResultToRValue = !Init->isGLValue() && !T->isPointerType() &&
!T->isObjCObjectPointerType();
} else
this->ConvertResultToRValue = false;
EvalResult.setSource(VD);
if (!this->visitDeclAndReturn(VD, S.inConstantContext()))
EvalResult.setInvalid();
S.EvaluatingDecl = nullptr;
updateGlobalTemporaries();
return std::move(this->EvalResult);
}
void EvalEmitter::emitLabel(LabelTy Label) { CurrentLabel = Label; }
EvalEmitter::LabelTy EvalEmitter::getLabel() { return NextLabel++; }
Scope::Local EvalEmitter::createLocal(Descriptor *D) {
// Allocate memory for a local.
auto Memory = std::make_unique<char[]>(sizeof(Block) + D->getAllocSize());
auto *B = new (Memory.get()) Block(Ctx.getEvalID(), D, /*isStatic=*/false);
B->invokeCtor();
// Initialize local variable inline descriptor.
InlineDescriptor &Desc = *reinterpret_cast<InlineDescriptor *>(B->rawData());
Desc.Desc = D;
Desc.Offset = sizeof(InlineDescriptor);
Desc.IsActive = true;
Desc.IsBase = false;
Desc.IsFieldMutable = false;
Desc.IsConst = false;
Desc.IsInitialized = false;
// Register the local.
unsigned Off = Locals.size();
Locals.insert({Off, std::move(Memory)});
return {Off, D};
}
bool EvalEmitter::jumpTrue(const LabelTy &Label) {
if (isActive()) {
if (S.Stk.pop<bool>())
ActiveLabel = Label;
}
return true;
}
bool EvalEmitter::jumpFalse(const LabelTy &Label) {
if (isActive()) {
if (!S.Stk.pop<bool>())
ActiveLabel = Label;
}
return true;
}
bool EvalEmitter::jump(const LabelTy &Label) {
if (isActive())
CurrentLabel = ActiveLabel = Label;
return true;
}
bool EvalEmitter::fallthrough(const LabelTy &Label) {
if (isActive())
ActiveLabel = Label;
CurrentLabel = Label;
return true;
}
bool EvalEmitter::speculate(const CallExpr *E, const LabelTy &EndLabel) {
size_t StackSizeBefore = S.Stk.size();
const Expr *Arg = E->getArg(0);
if (!this->visit(Arg)) {
S.Stk.clearTo(StackSizeBefore);
if (S.inConstantContext() || Arg->HasSideEffects(S.getASTContext()))
return this->emitBool(false, E);
return Invalid(S, OpPC);
}
PrimType T = Ctx.classify(Arg->getType()).value_or(PT_Ptr);
if (T == PT_Ptr) {
const auto &Ptr = S.Stk.pop<Pointer>();
return this->emitBool(CheckBCPResult(S, Ptr), E);
}
// Otherwise, this is fine!
if (!this->emitPop(T, E))
return false;
return this->emitBool(true, E);
}
template <PrimType OpType> bool EvalEmitter::emitRet(const SourceInfo &Info) {
if (!isActive())
return true;
using T = typename PrimConv<OpType>::T;
EvalResult.setValue(S.Stk.pop<T>().toAPValue(Ctx.getASTContext()));
return true;
}
template <> bool EvalEmitter::emitRet<PT_Ptr>(const SourceInfo &Info) {
if (!isActive())
return true;
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (Ptr.isFunctionPointer()) {
EvalResult.setValue(Ptr.toAPValue(Ctx.getASTContext()));
return true;
}
if (!EvalResult.checkReturnValue(S, Ctx, Ptr, Info))
return false;
if (CheckFullyInitialized && !EvalResult.checkFullyInitialized(S, Ptr))
return false;
// Implicitly convert lvalue to rvalue, if requested.
if (ConvertResultToRValue) {
if (!Ptr.isZero() && !Ptr.isDereferencable())
return false;
if (S.getLangOpts().CPlusPlus11 && Ptr.isBlockPointer() &&
!CheckFinalLoad(S, OpPC, Ptr)) {
return false;
}
// Never allow reading from a non-const pointer, unless the memory
// has been created in this evaluation.
if (!Ptr.isZero() && !Ptr.isConst() && Ptr.isBlockPointer() &&
Ptr.block()->getEvalID() != Ctx.getEvalID())
return false;
if (std::optional<APValue> V =
Ptr.toRValue(Ctx, EvalResult.getSourceType())) {
EvalResult.setValue(*V);
} else {
return false;
}
} else {
if (!Ptr.isLive() && !Ptr.isTemporary())
return false;
EvalResult.setValue(Ptr.toAPValue(Ctx.getASTContext()));
}
return true;
}
bool EvalEmitter::emitRetVoid(const SourceInfo &Info) {
EvalResult.setValid();
return true;
}
bool EvalEmitter::emitRetValue(const SourceInfo &Info) {
const auto &Ptr = S.Stk.pop<Pointer>();
if (!EvalResult.checkReturnValue(S, Ctx, Ptr, Info))
return false;
if (CheckFullyInitialized && !EvalResult.checkFullyInitialized(S, Ptr))
return false;
if (std::optional<APValue> APV =
Ptr.toRValue(S.getASTContext(), EvalResult.getSourceType())) {
EvalResult.setValue(*APV);
return true;
}
EvalResult.setInvalid();
return false;
}
bool EvalEmitter::emitGetPtrLocal(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
Block *B = getLocal(I);
S.Stk.push<Pointer>(B, sizeof(InlineDescriptor));
return true;
}
template <PrimType OpType>
bool EvalEmitter::emitGetLocal(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
using T = typename PrimConv<OpType>::T;
Block *B = getLocal(I);
S.Stk.push<T>(*reinterpret_cast<T *>(B->data()));
return true;
}
template <PrimType OpType>
bool EvalEmitter::emitSetLocal(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
using T = typename PrimConv<OpType>::T;
Block *B = getLocal(I);
*reinterpret_cast<T *>(B->data()) = S.Stk.pop<T>();
InlineDescriptor &Desc = *reinterpret_cast<InlineDescriptor *>(B->rawData());
Desc.IsInitialized = true;
return true;
}
bool EvalEmitter::emitDestroy(uint32_t I, const SourceInfo &Info) {
if (!isActive())
return true;
for (auto &Local : Descriptors[I]) {
Block *B = getLocal(Local.Offset);
S.deallocate(B);
}
return true;
}
/// Global temporaries (LifetimeExtendedTemporary) carry their value
/// around as an APValue, which codegen accesses.
/// We set their value once when creating them, but we don't update it
/// afterwards when code changes it later.
/// This is what we do here.
void EvalEmitter::updateGlobalTemporaries() {
for (const auto &[E, Temp] : S.SeenGlobalTemporaries) {
if (std::optional<unsigned> GlobalIndex = P.getGlobal(E)) {
const Pointer &Ptr = P.getPtrGlobal(*GlobalIndex);
APValue *Cached = Temp->getOrCreateValue(true);
if (std::optional<PrimType> T = Ctx.classify(E->getType())) {
TYPE_SWITCH(
*T, { *Cached = Ptr.deref<T>().toAPValue(Ctx.getASTContext()); });
} else {
if (std::optional<APValue> APV =
Ptr.toRValue(Ctx, Temp->getTemporaryExpr()->getType()))
*Cached = *APV;
}
}
}
S.SeenGlobalTemporaries.clear();
}
//===----------------------------------------------------------------------===//
// Opcode evaluators
//===----------------------------------------------------------------------===//
#define GET_EVAL_IMPL
#include "Opcodes.inc"
#undef GET_EVAL_IMPL