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 21 namespace clang { 22 namespace interp { 23 enum Opcode : uint32_t; 24 25 /// An emitter which links the program to bytecode for later use. 26 class ByteCodeEmitter { 27 protected: 28 using LabelTy = uint32_t; 29 using AddrTy = uintptr_t; 30 using Local = Scope::Local; 31 32 public: 33 /// Compiles the function into the module. 34 Function *compileFunc(const FunctionDecl *FuncDecl); 35 Function *compileObjCBlock(const BlockExpr *BE); 36 37 protected: 38 ByteCodeEmitter(Context &Ctx, Program &P) : Ctx(Ctx), P(P) {} 39 40 virtual ~ByteCodeEmitter() {} 41 42 /// Define a label. 43 void emitLabel(LabelTy Label); 44 /// Create a label. 45 LabelTy getLabel() { return ++NextLabel; } 46 47 /// Methods implemented by the compiler. 48 virtual bool visitFunc(const FunctionDecl *E) = 0; 49 virtual bool visitExpr(const Expr *E, bool DestroyToplevelScope) = 0; 50 virtual bool visitDeclAndReturn(const VarDecl *E, bool ConstantContext) = 0; 51 52 /// Emits jumps. 53 bool jumpTrue(const LabelTy &Label); 54 bool jumpFalse(const LabelTy &Label); 55 bool jump(const LabelTy &Label); 56 bool fallthrough(const LabelTy &Label); 57 58 /// We're always emitting bytecode. 59 bool isActive() const { return true; } 60 61 /// Callback for local registration. 62 Local createLocal(Descriptor *D); 63 64 /// Parameter indices. 65 llvm::DenseMap<const ParmVarDecl *, ParamOffset> Params; 66 /// Lambda captures. 67 llvm::DenseMap<const ValueDecl *, ParamOffset> LambdaCaptures; 68 /// Offset of the This parameter in a lambda record. 69 ParamOffset LambdaThisCapture{0, false}; 70 /// Local descriptors. 71 llvm::SmallVector<SmallVector<Local, 8>, 2> Descriptors; 72 73 private: 74 /// Current compilation context. 75 Context &Ctx; 76 /// Program to link to. 77 Program &P; 78 /// Index of the next available label. 79 LabelTy NextLabel = 0; 80 /// Offset of the next local variable. 81 unsigned NextLocalOffset = 0; 82 /// Label information for linker. 83 llvm::DenseMap<LabelTy, unsigned> LabelOffsets; 84 /// Location of label relocations. 85 llvm::DenseMap<LabelTy, llvm::SmallVector<unsigned, 5>> LabelRelocs; 86 /// Program code. 87 std::vector<std::byte> Code; 88 /// Opcode to expression mapping. 89 SourceMap SrcMap; 90 91 /// Returns the offset for a jump or records a relocation. 92 int32_t getOffset(LabelTy Label); 93 94 /// Emits an opcode. 95 template <typename... Tys> 96 bool emitOp(Opcode Op, const Tys &...Args, const SourceInfo &L); 97 98 protected: 99 #define GET_LINK_PROTO 100 #include "Opcodes.inc" 101 #undef GET_LINK_PROTO 102 }; 103 104 } // namespace interp 105 } // namespace clang 106 107 #endif 108