1//===--- ByteCodeEmitter.h - Instruction emitter for the VM ---------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Defines the instruction emitters.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_CLANG_AST_INTERP_LINKEMITTER_H
14#define LLVM_CLANG_AST_INTERP_LINKEMITTER_H
15
16#include "Context.h"
17#include "PrimType.h"
18#include "Program.h"
19#include "Source.h"
20
21namespace clang {
22namespace interp {
23enum Opcode : uint32_t;
24
25/// An emitter which links the program to bytecode for later use.
26class ByteCodeEmitter {
27protected:
28  using LabelTy = uint32_t;
29  using AddrTy = uintptr_t;
30  using Local = Scope::Local;
31
32public:
33  /// Compiles the function into the module.
34  Function *compileFunc(const FunctionDecl *FuncDecl);
35
36protected:
37  ByteCodeEmitter(Context &Ctx, Program &P) : Ctx(Ctx), P(P) {}
38
39  virtual ~ByteCodeEmitter() {}
40
41  /// Define a label.
42  void emitLabel(LabelTy Label);
43  /// Create a label.
44  LabelTy getLabel() { return ++NextLabel; }
45
46  /// Methods implemented by the compiler.
47  virtual bool visitFunc(const FunctionDecl *E) = 0;
48  virtual bool visitExpr(const Expr *E) = 0;
49  virtual bool visitDecl(const VarDecl *E) = 0;
50
51  /// Emits jumps.
52  bool jumpTrue(const LabelTy &Label);
53  bool jumpFalse(const LabelTy &Label);
54  bool jump(const LabelTy &Label);
55  bool fallthrough(const LabelTy &Label);
56
57  /// Callback for local registration.
58  Local createLocal(Descriptor *D);
59
60  /// Parameter indices.
61  llvm::DenseMap<const ParmVarDecl *, ParamOffset> Params;
62  /// Lambda captures.
63  llvm::DenseMap<const ValueDecl *, ParamOffset> LambdaCaptures;
64  /// Offset of the This parameter in a lambda record.
65  unsigned LambdaThisCapture = 0;
66  /// Local descriptors.
67  llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors;
68
69private:
70  /// Current compilation context.
71  Context &Ctx;
72  /// Program to link to.
73  Program &P;
74  /// Index of the next available label.
75  LabelTy NextLabel = 0;
76  /// Offset of the next local variable.
77  unsigned NextLocalOffset = 0;
78  /// Label information for linker.
79  llvm::DenseMap<LabelTy, unsigned> LabelOffsets;
80  /// Location of label relocations.
81  llvm::DenseMap<LabelTy, llvm::SmallVector<unsigned, 5>> LabelRelocs;
82  /// Program code.
83  std::vector<std::byte> Code;
84  /// Opcode to expression mapping.
85  SourceMap SrcMap;
86
87  /// Returns the offset for a jump or records a relocation.
88  int32_t getOffset(LabelTy Label);
89
90  /// Emits an opcode.
91  template <typename... Tys>
92  bool emitOp(Opcode Op, const Tys &... Args, const SourceInfo &L);
93
94protected:
95#define GET_LINK_PROTO
96#include "Opcodes.inc"
97#undef GET_LINK_PROTO
98};
99
100} // namespace interp
101} // namespace clang
102
103#endif
104