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 36 protected: 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 69 private: 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 94 protected: 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