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//===--- EvalEmitter.h - 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
//
//===----------------------------------------------------------------------===//
//
// Defines the instruction emitters.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_INTERP_EVALEMITTER_H
#define LLVM_CLANG_AST_INTERP_EVALEMITTER_H
#include "ByteCodeGenError.h"
#include "Context.h"
#include "InterpStack.h"
#include "InterpState.h"
#include "PrimType.h"
#include "Program.h"
#include "Source.h"
#include "llvm/Support/Error.h"
namespace clang {
namespace interp {
class Context;
class Function;
class InterpState;
class Program;
class SourceInfo;
enum Opcode : uint32_t;
/// An emitter which evaluates opcodes as they are emitted.
class EvalEmitter : public SourceMapper {
public:
using LabelTy = uint32_t;
using AddrTy = uintptr_t;
using Local = Scope::Local;
llvm::Expected<bool> interpretExpr(const Expr *E);
llvm::Expected<bool> interpretDecl(const VarDecl *VD);
protected:
EvalEmitter(Context &Ctx, Program &P, State &Parent, InterpStack &Stk,
APValue &Result);
virtual ~EvalEmitter() {}
/// Define a label.
void emitLabel(LabelTy Label);
/// Create a label.
LabelTy getLabel();
/// Methods implemented by the compiler.
virtual bool visitExpr(const Expr *E) = 0;
virtual bool visitDecl(const VarDecl *VD) = 0;
bool bail(const Stmt *S) { return bail(S->getBeginLoc()); }
bool bail(const Decl *D) { return bail(D->getBeginLoc()); }
bool bail(const SourceLocation &Loc);
/// Emits jumps.
bool jumpTrue(const LabelTy &Label);
bool jumpFalse(const LabelTy &Label);
bool jump(const LabelTy &Label);
bool fallthrough(const LabelTy &Label);
/// Callback for registering a local.
Local createLocal(Descriptor *D);
/// Returns the source location of the current opcode.
SourceInfo getSource(const Function *F, CodePtr PC) const override {
return (F && F->hasBody()) ? F->getSource(PC) : CurrentSource;
}
/// Parameter indices.
llvm::DenseMap<const ParmVarDecl *, unsigned> Params;
/// Lambda captures.
/// Map from Decl* to [Offset, IsReference] pair.
llvm::DenseMap<const ValueDecl *, std::pair<unsigned, bool>> LambdaCaptures;
unsigned LambdaThisCapture;
/// Local descriptors.
llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
private:
/// Current compilation context.
Context &Ctx;
/// Current program.
Program &P;
/// Callee evaluation state.
InterpState S;
/// Location to write the result to.
APValue &Result;
/// Temporaries which require storage.
llvm::DenseMap<unsigned, std::unique_ptr<char[]>> Locals;
Block *getLocal(unsigned Index) const {
auto It = Locals.find(Index);
assert(It != Locals.end() && "Missing local variable");
return reinterpret_cast<Block *>(It->second.get());
}
// The emitter always tracks the current instruction and sets OpPC to a token
// value which is mapped to the location of the opcode being evaluated.
CodePtr OpPC;
/// Location of a failure.
std::optional<SourceLocation> BailLocation;
/// Location of the current instruction.
SourceInfo CurrentSource;
/// Next label ID to generate - first label is 1.
LabelTy NextLabel = 1;
/// Label being executed - 0 is the entry label.
LabelTy CurrentLabel = 0;
/// Active block which should be executed.
LabelTy ActiveLabel = 0;
/// Since expressions can only jump forward, predicated execution is
/// used to deal with if-else statements.
bool isActive() const { return CurrentLabel == ActiveLabel; }
protected:
#define GET_EVAL_PROTO
#include "Opcodes.inc"
#undef GET_EVAL_PROTO
};
} // namespace interp
} // namespace clang
#endif
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