1 //===-- llvm/MC/MCSymbolizer.h - MCSymbolizer class -------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains the declaration of the MCSymbolizer class, which is used 11 // to symbolize instructions decoded from an object, that is, transform their 12 // immediate operands to MCExprs. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_MC_MCDISASSEMBLER_MCSYMBOLIZER_H 17 #define LLVM_MC_MCDISASSEMBLER_MCSYMBOLIZER_H 18 19 #include "llvm/MC/MCDisassembler/MCRelocationInfo.h" 20 #include "llvm/Support/Compiler.h" 21 #include "llvm/Support/DataTypes.h" 22 #include <cassert> 23 #include <memory> 24 25 namespace llvm { 26 27 class MCContext; 28 class MCInst; 29 class raw_ostream; 30 31 /// \brief Symbolize and annotate disassembled instructions. 32 /// 33 /// For now this mimics the old symbolization logic (from both ARM and x86), that 34 /// relied on user-provided (C API) callbacks to do the actual symbol lookup in 35 /// the object file. This was moved to MCExternalSymbolizer. 36 /// A better API would not rely on actually calling the two methods here from 37 /// inside each disassembler, but would use the instr info to determine what 38 /// operands are actually symbolizable, and in what way. I don't think this 39 /// information exists right now. 40 class MCSymbolizer { 41 MCSymbolizer(const MCSymbolizer &) = delete; 42 void operator=(const MCSymbolizer &) = delete; 43 44 protected: 45 MCContext &Ctx; 46 std::unique_ptr<MCRelocationInfo> RelInfo; 47 48 public: 49 /// \brief Construct an MCSymbolizer, taking ownership of \p RelInfo. MCSymbolizer(MCContext & Ctx,std::unique_ptr<MCRelocationInfo> RelInfo)50 MCSymbolizer(MCContext &Ctx, std::unique_ptr<MCRelocationInfo> RelInfo) 51 : Ctx(Ctx), RelInfo(std::move(RelInfo)) { 52 } 53 54 virtual ~MCSymbolizer(); 55 56 /// \brief Try to add a symbolic operand instead of \p Value to the MCInst. 57 /// 58 /// Instead of having a difficult to read immediate, a symbolic operand would 59 /// represent this immediate in a more understandable way, for instance as a 60 /// symbol or an offset from a symbol. Relocations can also be used to enrich 61 /// the symbolic expression. 62 /// \param Inst - The MCInst where to insert the symbolic operand. 63 /// \param cStream - Stream to print comments and annotations on. 64 /// \param Value - Operand value, pc-adjusted by the caller if necessary. 65 /// \param Address - Load address of the instruction. 66 /// \param IsBranch - Is the instruction a branch? 67 /// \param Offset - Byte offset of the operand inside the inst. 68 /// \param InstSize - Size of the instruction in bytes. 69 /// \return Whether a symbolic operand was added. 70 virtual bool tryAddingSymbolicOperand(MCInst &Inst, raw_ostream &cStream, 71 int64_t Value, uint64_t Address, 72 bool IsBranch, uint64_t Offset, 73 uint64_t InstSize) = 0; 74 75 /// \brief Try to add a comment on the PC-relative load. 76 /// For instance, in Mach-O, this is used to add annotations to instructions 77 /// that use C string literals, as found in __cstring. 78 virtual void tryAddingPcLoadReferenceComment(raw_ostream &cStream, 79 int64_t Value, 80 uint64_t Address) = 0; 81 }; 82 83 } 84 85 #endif 86