1 //===-- llvm/MC/MCDisassembler.h - Disassembler interface -------*- 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 #ifndef MCDISASSEMBLER_H 10 #define MCDISASSEMBLER_H 11 12 #include "llvm/Support/DataTypes.h" 13 #include "llvm-c/Disassembler.h" 14 15 namespace llvm { 16 17 class MCInst; 18 class MCSubtargetInfo; 19 class MemoryObject; 20 class raw_ostream; 21 class MCContext; 22 23 struct EDInstInfo; 24 25 /// MCDisassembler - Superclass for all disassemblers. Consumes a memory region 26 /// and provides an array of assembly instructions. 27 class MCDisassembler { 28 public: 29 /// Ternary decode status. Most backends will just use Fail and 30 /// Success, however some have a concept of an instruction with 31 /// understandable semantics but which is architecturally 32 /// incorrect. An example of this is ARM UNPREDICTABLE instructions 33 /// which are disassemblable but cause undefined behaviour. 34 /// 35 /// Because it makes sense to disassemble these instructions, there 36 /// is a "soft fail" failure mode that indicates the MCInst& is 37 /// valid but architecturally incorrect. 38 /// 39 /// The enum numbers are deliberately chosen such that reduction 40 /// from Success->SoftFail ->Fail can be done with a simple 41 /// bitwise-AND: 42 /// 43 /// LEFT & TOP = | Success Unpredictable Fail 44 /// --------------+----------------------------------- 45 /// Success | Success Unpredictable Fail 46 /// Unpredictable | Unpredictable Unpredictable Fail 47 /// Fail | Fail Fail Fail 48 /// 49 /// An easy way of encoding this is as 0b11, 0b01, 0b00 for 50 /// Success, SoftFail, Fail respectively. 51 enum DecodeStatus { 52 Fail = 0, 53 SoftFail = 1, 54 Success = 3 55 }; 56 57 /// Constructor - Performs initial setup for the disassembler. 58 MCDisassembler(const MCSubtargetInfo &STI) : GetOpInfo(0), SymbolLookUp(0), 59 DisInfo(0), Ctx(0), 60 STI(STI), CommentStream(0) {} 61 62 virtual ~MCDisassembler(); 63 64 /// getInstruction - Returns the disassembly of a single instruction. 65 /// 66 /// @param instr - An MCInst to populate with the contents of the 67 /// instruction. 68 /// @param size - A value to populate with the size of the instruction, or 69 /// the number of bytes consumed while attempting to decode 70 /// an invalid instruction. 71 /// @param region - The memory object to use as a source for machine code. 72 /// @param address - The address, in the memory space of region, of the first 73 /// byte of the instruction. 74 /// @param vStream - The stream to print warnings and diagnostic messages on. 75 /// @param cStream - The stream to print comments and annotations on. 76 /// @return - MCDisassembler::Success if the instruction is valid, 77 /// MCDisassembler::SoftFail if the instruction was 78 /// disassemblable but invalid, 79 /// MCDisassembler::Fail if the instruction was invalid. 80 virtual DecodeStatus getInstruction(MCInst& instr, 81 uint64_t& size, 82 const MemoryObject ®ion, 83 uint64_t address, 84 raw_ostream &vStream, 85 raw_ostream &cStream) const = 0; 86 87 /// getEDInfo - Returns the enhanced instruction information corresponding to 88 /// the disassembler. 89 /// 90 /// @return - An array of instruction information, with one entry for 91 /// each MCInst opcode this disassembler returns. 92 /// NULL if there is no info for this target. 93 virtual EDInstInfo *getEDInfo() const { return (EDInstInfo*)0; } 94 95 private: 96 // 97 // Hooks for symbolic disassembly via the public 'C' interface. 98 // 99 // The function to get the symbolic information for operands. 100 LLVMOpInfoCallback GetOpInfo; 101 // The function to lookup a symbol name. 102 LLVMSymbolLookupCallback SymbolLookUp; 103 // The pointer to the block of symbolic information for above call back. 104 void *DisInfo; 105 // The assembly context for creating symbols and MCExprs in place of 106 // immediate operands when there is symbolic information. 107 MCContext *Ctx; 108 protected: 109 // Subtarget information, for instruction decoding predicates if required. 110 const MCSubtargetInfo &STI; 111 112 public: 113 void setupForSymbolicDisassembly(LLVMOpInfoCallback getOpInfo, 114 LLVMSymbolLookupCallback symbolLookUp, 115 void *disInfo, 116 MCContext *ctx) { 117 GetOpInfo = getOpInfo; 118 SymbolLookUp = symbolLookUp; 119 DisInfo = disInfo; 120 Ctx = ctx; 121 } 122 LLVMOpInfoCallback getLLVMOpInfoCallback() const { return GetOpInfo; } 123 LLVMSymbolLookupCallback getLLVMSymbolLookupCallback() const { 124 return SymbolLookUp; 125 } 126 void *getDisInfoBlock() const { return DisInfo; } 127 MCContext *getMCContext() const { return Ctx; } 128 129 // Marked mutable because we cache it inside the disassembler, rather than 130 // having to pass it around as an argument through all the autogenerated code. 131 mutable raw_ostream *CommentStream; 132 }; 133 134 } // namespace llvm 135 136 #endif 137
