1 //===-- lib/MC/Disassembler.cpp - Disassembler Public C 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 10 #include "Disassembler.h" 11 #include "llvm-c/Disassembler.h" 12 13 #include "llvm/MC/MCAsmInfo.h" 14 #include "llvm/MC/MCDisassembler.h" 15 #include "llvm/MC/MCInst.h" 16 #include "llvm/MC/MCInstPrinter.h" 17 #include "llvm/MC/MCContext.h" 18 #include "llvm/Target/TargetRegistry.h" 19 #include "llvm/Target/TargetAsmInfo.h" // FIXME. 20 #include "llvm/Target/TargetMachine.h" // FIXME. 21 #include "llvm/Target/TargetSelect.h" 22 #include "llvm/Support/MemoryObject.h" 23 24 namespace llvm { 25 class Target; 26 } // namespace llvm 27 using namespace llvm; 28 29 // LLVMCreateDisasm() creates a disassembler for the TripleName. Symbolic 30 // disassembly is supported by passing a block of information in the DisInfo 31 // parameter and specifying the TagType and callback functions as described in 32 // the header llvm-c/Disassembler.h . The pointer to the block and the 33 // functions can all be passed as NULL. If successful, this returns a 34 // disassembler context. If not, it returns NULL. 35 // 36 LLVMDisasmContextRef LLVMCreateDisasm(const char *TripleName, void *DisInfo, 37 int TagType, LLVMOpInfoCallback GetOpInfo, 38 LLVMSymbolLookupCallback SymbolLookUp) { 39 // Initialize targets and assembly printers/parsers. 40 llvm::InitializeAllTargetInfos(); 41 // FIXME: We shouldn't need to initialize the Target(Machine)s. 42 llvm::InitializeAllTargets(); 43 llvm::InitializeAllMCAsmInfos(); 44 llvm::InitializeAllMCCodeGenInfos(); 45 llvm::InitializeAllMCRegisterInfos(); 46 llvm::InitializeAllAsmPrinters(); 47 llvm::InitializeAllAsmParsers(); 48 llvm::InitializeAllDisassemblers(); 49 50 // Get the target. 51 std::string Error; 52 const Target *TheTarget = TargetRegistry::lookupTarget(TripleName, Error); 53 assert(TheTarget && "Unable to create target!"); 54 55 // Get the assembler info needed to setup the MCContext. 56 const MCAsmInfo *MAI = TheTarget->createMCAsmInfo(TripleName); 57 assert(MAI && "Unable to create target asm info!"); 58 59 const MCRegisterInfo *MRI = TheTarget->createMCRegInfo(TripleName); 60 assert(MRI && "Unable to create target register info!"); 61 62 // Package up features to be passed to target/subtarget 63 std::string FeaturesStr; 64 std::string CPU; 65 66 // FIXME: We shouldn't need to do this (and link in codegen). 67 // When we split this out, we should do it in a way that makes 68 // it straightforward to switch subtargets on the fly. 69 TargetMachine *TM = TheTarget->createTargetMachine(TripleName, CPU, 70 FeaturesStr); 71 assert(TM && "Unable to create target machine!"); 72 73 // Get the target assembler info needed to setup the context. 74 const TargetAsmInfo *tai = new TargetAsmInfo(*TM); 75 assert(tai && "Unable to create target assembler!"); 76 77 // Set up the MCContext for creating symbols and MCExpr's. 78 MCContext *Ctx = new MCContext(*MAI, *MRI, tai); 79 assert(Ctx && "Unable to create MCContext!"); 80 81 // Set up disassembler. 82 MCDisassembler *DisAsm = TheTarget->createMCDisassembler(); 83 assert(DisAsm && "Unable to create disassembler!"); 84 DisAsm->setupForSymbolicDisassembly(GetOpInfo, DisInfo, Ctx); 85 86 // Set up the instruction printer. 87 int AsmPrinterVariant = MAI->getAssemblerDialect(); 88 MCInstPrinter *IP = TheTarget->createMCInstPrinter(AsmPrinterVariant, 89 *MAI); 90 assert(IP && "Unable to create instruction printer!"); 91 92 LLVMDisasmContext *DC = new LLVMDisasmContext(TripleName, DisInfo, TagType, 93 GetOpInfo, SymbolLookUp, 94 TheTarget, MAI, MRI, TM, tai, 95 Ctx, DisAsm, IP); 96 assert(DC && "Allocation failure!"); 97 return DC; 98 } 99 100 // 101 // LLVMDisasmDispose() disposes of the disassembler specified by the context. 102 // 103 void LLVMDisasmDispose(LLVMDisasmContextRef DCR){ 104 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 105 delete DC; 106 } 107 108 namespace { 109 // 110 // The memory object created by LLVMDisasmInstruction(). 111 // 112 class DisasmMemoryObject : public MemoryObject { 113 uint8_t *Bytes; 114 uint64_t Size; 115 uint64_t BasePC; 116 public: 117 DisasmMemoryObject(uint8_t *bytes, uint64_t size, uint64_t basePC) : 118 Bytes(bytes), Size(size), BasePC(basePC) {} 119 120 uint64_t getBase() const { return BasePC; } 121 uint64_t getExtent() const { return Size; } 122 123 int readByte(uint64_t Addr, uint8_t *Byte) const { 124 if (Addr - BasePC >= Size) 125 return -1; 126 *Byte = Bytes[Addr - BasePC]; 127 return 0; 128 } 129 }; 130 } // end anonymous namespace 131 132 // 133 // LLVMDisasmInstruction() disassembles a single instruction using the 134 // disassembler context specified in the parameter DC. The bytes of the 135 // instruction are specified in the parameter Bytes, and contains at least 136 // BytesSize number of bytes. The instruction is at the address specified by 137 // the PC parameter. If a valid instruction can be disassembled its string is 138 // returned indirectly in OutString which whos size is specified in the 139 // parameter OutStringSize. This function returns the number of bytes in the 140 // instruction or zero if there was no valid instruction. If this function 141 // returns zero the caller will have to pick how many bytes they want to step 142 // over by printing a .byte, .long etc. to continue. 143 // 144 size_t LLVMDisasmInstruction(LLVMDisasmContextRef DCR, uint8_t *Bytes, 145 uint64_t BytesSize, uint64_t PC, char *OutString, 146 size_t OutStringSize){ 147 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 148 // Wrap the pointer to the Bytes, BytesSize and PC in a MemoryObject. 149 DisasmMemoryObject MemoryObject(Bytes, BytesSize, PC); 150 151 uint64_t Size; 152 MCInst Inst; 153 const MCDisassembler *DisAsm = DC->getDisAsm(); 154 MCInstPrinter *IP = DC->getIP(); 155 if (!DisAsm->getInstruction(Inst, Size, MemoryObject, PC, /*REMOVE*/ nulls())) 156 return 0; 157 158 SmallVector<char, 64> InsnStr; 159 raw_svector_ostream OS(InsnStr); 160 IP->printInst(&Inst, OS); 161 OS.flush(); 162 163 assert(OutStringSize != 0 && "Output buffer cannot be zero size"); 164 size_t OutputSize = std::min(OutStringSize-1, InsnStr.size()); 165 std::memcpy(OutString, InsnStr.data(), OutputSize); 166 OutString[OutputSize] = '\0'; // Terminate string. 167 168 return Size; 169 } 170