llvm-project/clang/lib/AST/Interp/ByteCodeEmitter.h

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//===--- ByteCodeEmitter.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_LINKEMITTER_H
#define LLVM_CLANG_AST_INTERP_LINKEMITTER_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 SourceInfo;
enum Opcode : uint32_t;
/// An emitter which links the program to bytecode for later use.
class ByteCodeEmitter {
protected:
using LabelTy = uint32_t;
using AddrTy = uintptr_t;
using Local = Scope::Local;
public:
/// Compiles the function into the module.
llvm::Expected<Function *> compileFunc(const FunctionDecl *F);
protected:
ByteCodeEmitter(Context &Ctx, Program &P) : Ctx(Ctx), P(P) {}
virtual ~ByteCodeEmitter() {}
/// Define a label.
void emitLabel(LabelTy Label);
/// Create a label.
LabelTy getLabel() { return ++NextLabel; }
/// Methods implemented by the compiler.
virtual bool visitFunc(const FunctionDecl *E) = 0;
virtual bool visitExpr(const Expr *E) = 0;
virtual bool visitDecl(const VarDecl *E) = 0;
/// Bails out if a given node cannot be compiled.
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 local registration.
Local createLocal(Descriptor *D);
/// Parameter indices.
llvm::DenseMap<const ParmVarDecl *, unsigned> Params;
/// Local descriptors.
llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
private:
/// Current compilation context.
Context &Ctx;
/// Program to link to.
Program &P;
/// Index of the next available label.
LabelTy NextLabel = 0;
/// Offset of the next local variable.
unsigned NextLocalOffset = 0;
/// Location of a failure.
llvm::Optional<SourceLocation> BailLocation;
/// Label information for linker.
llvm::DenseMap<LabelTy, unsigned> LabelOffsets;
/// Location of label relocations.
llvm::DenseMap<LabelTy, llvm::SmallVector<unsigned, 5>> LabelRelocs;
/// Program code.
std::vector<char> Code;
/// Opcode to expression mapping.
SourceMap SrcMap;
/// Returns the offset for a jump or records a relocation.
int32_t getOffset(LabelTy Label);
/// Emits an opcode.
template <typename... Tys>
bool emitOp(Opcode Op, const Tys &... Args, const SourceInfo &L);
protected:
#define GET_LINK_PROTO
#include "Opcodes.inc"
#undef GET_LINK_PROTO
};
} // namespace interp
} // namespace clang
#endif