1 //===-- lib/MC/Disassembler.cpp - Disassembler Public C Interface ---------===// 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 #include "Disassembler.h" 11 #include "llvm-c/Disassembler.h" 12 13 #include "llvm/MC/MCAsmInfo.h" 14 #include "llvm/MC/MCContext.h" 15 #include "llvm/MC/MCDisassembler.h" 16 #include "llvm/MC/MCInst.h" 17 #include "llvm/MC/MCInstPrinter.h" 18 #include "llvm/MC/MCRegisterInfo.h" 19 #include "llvm/Support/MemoryObject.h" 20 #include "llvm/Support/TargetRegistry.h" 21 #include "llvm/Support/TargetSelect.h" 22 23 namespace llvm { 24 class Target; 25 } // namespace llvm 26 using namespace llvm; 27 28 // LLVMCreateDisasm() creates a disassembler for the TripleName. Symbolic 29 // disassembly is supported by passing a block of information in the DisInfo 30 // parameter and specifying the TagType and callback functions as described in 31 // the header llvm-c/Disassembler.h . The pointer to the block and the 32 // functions can all be passed as NULL. If successful, this returns a 33 // disassembler context. If not, it returns NULL. 34 // 35 LLVMDisasmContextRef LLVMCreateDisasm(const char *TripleName, void *DisInfo, 36 int TagType, LLVMOpInfoCallback GetOpInfo, 37 LLVMSymbolLookupCallback SymbolLookUp) { 38 // Initialize targets and assembly printers/parsers. 39 llvm::InitializeAllTargetInfos(); 40 llvm::InitializeAllTargetMCs(); 41 llvm::InitializeAllAsmParsers(); 42 llvm::InitializeAllDisassemblers(); 43 44 // Get the target. 45 std::string Error; 46 const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error); 47 assert(TheTarget && "Unable to create target!"); 48 49 // Get the assembler info needed to setup the MCContext. 50 const MCAsmInfo *MAI = TheTarget->createMCAsmInfo(TripleName); 51 assert(MAI && "Unable to create target asm info!"); 52 53 const MCRegisterInfo *MRI = TheTarget->createMCRegInfo(TripleName); 54 assert(MRI && "Unable to create target register info!"); 55 56 // Package up features to be passed to target/subtarget 57 std::string FeaturesStr; 58 std::string CPU; 59 60 // Set up the MCContext for creating symbols and MCExpr's. 61 MCContext *Ctx = new MCContext(*MAI, *MRI, 0); 62 assert(Ctx && "Unable to create MCContext!"); 63 64 // Set up disassembler. 65 MCDisassembler *DisAsm = TheTarget->createMCDisassembler(); 66 assert(DisAsm && "Unable to create disassembler!"); 67 DisAsm->setupForSymbolicDisassembly(GetOpInfo, DisInfo, Ctx); 68 69 // Set up the instruction printer. 70 int AsmPrinterVariant = MAI->getAssemblerDialect(); 71 MCInstPrinter *IP = TheTarget->createMCInstPrinter(AsmPrinterVariant, 72 *MAI); 73 assert(IP && "Unable to create instruction printer!"); 74 75 LLVMDisasmContext *DC = new LLVMDisasmContext(TripleName, DisInfo, TagType, 76 GetOpInfo, SymbolLookUp, 77 TheTarget, MAI, MRI, 78 Ctx, DisAsm, IP); 79 assert(DC && "Allocation failure!"); 80 return DC; 81 } 82 83 // 84 // LLVMDisasmDispose() disposes of the disassembler specified by the context. 85 // 86 void LLVMDisasmDispose(LLVMDisasmContextRef DCR){ 87 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 88 delete DC; 89 } 90 91 namespace { 92 // 93 // The memory object created by LLVMDisasmInstruction(). 94 // 95 class DisasmMemoryObject : public MemoryObject { 96 uint8_t *Bytes; 97 uint64_t Size; 98 uint64_t BasePC; 99 public: 100 DisasmMemoryObject(uint8_t *bytes, uint64_t size, uint64_t basePC) : 101 Bytes(bytes), Size(size), BasePC(basePC) {} 102 103 uint64_t getBase() const { return BasePC; } 104 uint64_t getExtent() const { return Size; } 105 106 int readByte(uint64_t Addr, uint8_t *Byte) const { 107 if (Addr - BasePC >= Size) 108 return -1; 109 *Byte = Bytes[Addr - BasePC]; 110 return 0; 111 } 112 }; 113 } // end anonymous namespace 114 115 // 116 // LLVMDisasmInstruction() disassembles a single instruction using the 117 // disassembler context specified in the parameter DC. The bytes of the 118 // instruction are specified in the parameter Bytes, and contains at least 119 // BytesSize number of bytes. The instruction is at the address specified by 120 // the PC parameter. If a valid instruction can be disassembled its string is 121 // returned indirectly in OutString which whos size is specified in the 122 // parameter OutStringSize. This function returns the number of bytes in the 123 // instruction or zero if there was no valid instruction. If this function 124 // returns zero the caller will have to pick how many bytes they want to step 125 // over by printing a .byte, .long etc. to continue. 126 // 127 size_t LLVMDisasmInstruction(LLVMDisasmContextRef DCR, uint8_t *Bytes, 128 uint64_t BytesSize, uint64_t PC, char *OutString, 129 size_t OutStringSize){ 130 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 131 // Wrap the pointer to the Bytes, BytesSize and PC in a MemoryObject. 132 DisasmMemoryObject MemoryObject(Bytes, BytesSize, PC); 133 134 uint64_t Size; 135 MCInst Inst; 136 const MCDisassembler *DisAsm = DC->getDisAsm(); 137 MCInstPrinter *IP = DC->getIP(); 138 MCDisassembler::DecodeStatus S; 139 S = DisAsm->getInstruction(Inst, Size, MemoryObject, PC, 140 /*REMOVE*/ nulls()); 141 switch (S) { 142 case MCDisassembler::Fail: 143 case MCDisassembler::SoftFail: 144 // FIXME: Do something different for soft failure modes? 145 return 0; 146 147 case MCDisassembler::Success: { 148 SmallVector<char, 64> InsnStr; 149 raw_svector_ostream OS(InsnStr); 150 IP->printInst(&Inst, OS); 151 OS.flush(); 152 153 assert(OutStringSize != 0 && "Output buffer cannot be zero size"); 154 size_t OutputSize = std::min(OutStringSize-1, InsnStr.size()); 155 std::memcpy(OutString, InsnStr.data(), OutputSize); 156 OutString[OutputSize] = '\0'; // Terminate string. 157 158 return Size; 159 } 160 } 161 return 0; 162 } 163