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 #include "llvm/MC/MCAsmInfo.h" 13 #include "llvm/MC/MCContext.h" 14 #include "llvm/MC/MCDisassembler.h" 15 #include "llvm/MC/MCInst.h" 16 #include "llvm/MC/MCInstPrinter.h" 17 #include "llvm/MC/MCInstrInfo.h" 18 #include "llvm/MC/MCRegisterInfo.h" 19 #include "llvm/MC/MCRelocationInfo.h" 20 #include "llvm/MC/MCSubtargetInfo.h" 21 #include "llvm/MC/MCSymbolizer.h" 22 #include "llvm/Support/ErrorHandling.h" 23 #include "llvm/Support/MemoryObject.h" 24 #include "llvm/Support/TargetRegistry.h" 25 26 namespace llvm { 27 class Target; 28 } // namespace llvm 29 using namespace llvm; 30 31 // LLVMCreateDisasm() creates a disassembler for the TripleName. Symbolic 32 // disassembly is supported by passing a block of information in the DisInfo 33 // parameter and specifying the TagType and callback functions as described in 34 // the header llvm-c/Disassembler.h . The pointer to the block and the 35 // functions can all be passed as NULL. If successful, this returns a 36 // disassembler context. If not, it returns NULL. 37 // 38 LLVMDisasmContextRef LLVMCreateDisasmCPU(const char *Triple, const char *CPU, 39 void *DisInfo, int TagType, 40 LLVMOpInfoCallback GetOpInfo, 41 LLVMSymbolLookupCallback SymbolLookUp){ 42 // Get the target. 43 std::string Error; 44 const Target *TheTarget = TargetRegistry::lookupTarget(Triple, Error); 45 if (!TheTarget) 46 return 0; 47 48 const MCRegisterInfo *MRI = TheTarget->createMCRegInfo(Triple); 49 if (!MRI) 50 return 0; 51 52 // Get the assembler info needed to setup the MCContext. 53 const MCAsmInfo *MAI = TheTarget->createMCAsmInfo(*MRI, Triple); 54 if (!MAI) 55 return 0; 56 57 const MCInstrInfo *MII = TheTarget->createMCInstrInfo(); 58 if (!MII) 59 return 0; 60 61 // Package up features to be passed to target/subtarget 62 std::string FeaturesStr; 63 64 const MCSubtargetInfo *STI = TheTarget->createMCSubtargetInfo(Triple, CPU, 65 FeaturesStr); 66 if (!STI) 67 return 0; 68 69 // Set up the MCContext for creating symbols and MCExpr's. 70 MCContext *Ctx = new MCContext(MAI, MRI, 0); 71 if (!Ctx) 72 return 0; 73 74 // Set up disassembler. 75 MCDisassembler *DisAsm = TheTarget->createMCDisassembler(*STI); 76 if (!DisAsm) 77 return 0; 78 79 OwningPtr<MCRelocationInfo> RelInfo( 80 TheTarget->createMCRelocationInfo(Triple, *Ctx)); 81 if (!RelInfo) 82 return 0; 83 84 OwningPtr<MCSymbolizer> Symbolizer( 85 TheTarget->createMCSymbolizer(Triple, GetOpInfo, SymbolLookUp, DisInfo, 86 Ctx, RelInfo.take())); 87 DisAsm->setSymbolizer(Symbolizer); 88 DisAsm->setupForSymbolicDisassembly(GetOpInfo, SymbolLookUp, DisInfo, 89 Ctx, RelInfo); 90 // Set up the instruction printer. 91 int AsmPrinterVariant = MAI->getAssemblerDialect(); 92 MCInstPrinter *IP = TheTarget->createMCInstPrinter(AsmPrinterVariant, 93 *MAI, *MII, *MRI, *STI); 94 if (!IP) 95 return 0; 96 97 LLVMDisasmContext *DC = new LLVMDisasmContext(Triple, DisInfo, TagType, 98 GetOpInfo, SymbolLookUp, 99 TheTarget, MAI, MRI, 100 STI, MII, Ctx, DisAsm, IP); 101 if (!DC) 102 return 0; 103 104 return DC; 105 } 106 107 LLVMDisasmContextRef LLVMCreateDisasm(const char *Triple, void *DisInfo, 108 int TagType, LLVMOpInfoCallback GetOpInfo, 109 LLVMSymbolLookupCallback SymbolLookUp) { 110 return LLVMCreateDisasmCPU(Triple, "", DisInfo, TagType, GetOpInfo, 111 SymbolLookUp); 112 } 113 114 // 115 // LLVMDisasmDispose() disposes of the disassembler specified by the context. 116 // 117 void LLVMDisasmDispose(LLVMDisasmContextRef DCR){ 118 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 119 delete DC; 120 } 121 122 namespace { 123 // 124 // The memory object created by LLVMDisasmInstruction(). 125 // 126 class DisasmMemoryObject : public MemoryObject { 127 uint8_t *Bytes; 128 uint64_t Size; 129 uint64_t BasePC; 130 public: 131 DisasmMemoryObject(uint8_t *bytes, uint64_t size, uint64_t basePC) : 132 Bytes(bytes), Size(size), BasePC(basePC) {} 133 134 uint64_t getBase() const { return BasePC; } 135 uint64_t getExtent() const { return Size; } 136 137 int readByte(uint64_t Addr, uint8_t *Byte) const { 138 if (Addr - BasePC >= Size) 139 return -1; 140 *Byte = Bytes[Addr - BasePC]; 141 return 0; 142 } 143 }; 144 } // end anonymous namespace 145 146 // 147 // LLVMDisasmInstruction() disassembles a single instruction using the 148 // disassembler context specified in the parameter DC. The bytes of the 149 // instruction are specified in the parameter Bytes, and contains at least 150 // BytesSize number of bytes. The instruction is at the address specified by 151 // the PC parameter. If a valid instruction can be disassembled its string is 152 // returned indirectly in OutString which whos size is specified in the 153 // parameter OutStringSize. This function returns the number of bytes in the 154 // instruction or zero if there was no valid instruction. If this function 155 // returns zero the caller will have to pick how many bytes they want to step 156 // over by printing a .byte, .long etc. to continue. 157 // 158 size_t LLVMDisasmInstruction(LLVMDisasmContextRef DCR, uint8_t *Bytes, 159 uint64_t BytesSize, uint64_t PC, char *OutString, 160 size_t OutStringSize){ 161 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 162 // Wrap the pointer to the Bytes, BytesSize and PC in a MemoryObject. 163 DisasmMemoryObject MemoryObject(Bytes, BytesSize, PC); 164 165 uint64_t Size; 166 MCInst Inst; 167 const MCDisassembler *DisAsm = DC->getDisAsm(); 168 MCInstPrinter *IP = DC->getIP(); 169 MCDisassembler::DecodeStatus S; 170 S = DisAsm->getInstruction(Inst, Size, MemoryObject, PC, 171 /*REMOVE*/ nulls(), DC->CommentStream); 172 switch (S) { 173 case MCDisassembler::Fail: 174 case MCDisassembler::SoftFail: 175 // FIXME: Do something different for soft failure modes? 176 return 0; 177 178 case MCDisassembler::Success: { 179 DC->CommentStream.flush(); 180 StringRef Comments = DC->CommentsToEmit.str(); 181 182 SmallVector<char, 64> InsnStr; 183 raw_svector_ostream OS(InsnStr); 184 IP->printInst(&Inst, OS, Comments); 185 OS.flush(); 186 187 // Tell the comment stream that the vector changed underneath it. 188 DC->CommentsToEmit.clear(); 189 DC->CommentStream.resync(); 190 191 assert(OutStringSize != 0 && "Output buffer cannot be zero size"); 192 size_t OutputSize = std::min(OutStringSize-1, InsnStr.size()); 193 std::memcpy(OutString, InsnStr.data(), OutputSize); 194 OutString[OutputSize] = '\0'; // Terminate string. 195 196 return Size; 197 } 198 } 199 llvm_unreachable("Invalid DecodeStatus!"); 200 } 201 202 // 203 // LLVMSetDisasmOptions() sets the disassembler's options. It returns 1 if it 204 // can set all the Options and 0 otherwise. 205 // 206 int LLVMSetDisasmOptions(LLVMDisasmContextRef DCR, uint64_t Options){ 207 if (Options & LLVMDisassembler_Option_UseMarkup){ 208 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 209 MCInstPrinter *IP = DC->getIP(); 210 IP->setUseMarkup(1); 211 Options &= ~LLVMDisassembler_Option_UseMarkup; 212 } 213 if (Options & LLVMDisassembler_Option_PrintImmHex){ 214 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 215 MCInstPrinter *IP = DC->getIP(); 216 IP->setPrintImmHex(1); 217 Options &= ~LLVMDisassembler_Option_PrintImmHex; 218 } 219 if (Options & LLVMDisassembler_Option_AsmPrinterVariant){ 220 LLVMDisasmContext *DC = (LLVMDisasmContext *)DCR; 221 // Try to set up the new instruction printer. 222 const MCAsmInfo *MAI = DC->getAsmInfo(); 223 const MCInstrInfo *MII = DC->getInstrInfo(); 224 const MCRegisterInfo *MRI = DC->getRegisterInfo(); 225 const MCSubtargetInfo *STI = DC->getSubtargetInfo(); 226 int AsmPrinterVariant = MAI->getAssemblerDialect(); 227 AsmPrinterVariant = AsmPrinterVariant == 0 ? 1 : 0; 228 MCInstPrinter *IP = DC->getTarget()->createMCInstPrinter( 229 AsmPrinterVariant, *MAI, *MII, *MRI, *STI); 230 if (IP) { 231 DC->setIP(IP); 232 Options &= ~LLVMDisassembler_Option_AsmPrinterVariant; 233 } 234 } 235 return (Options == 0); 236 } 237