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Diffstat (limited to 'llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp')
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diff --git a/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp new file mode 100644 index 000000000000..9a635bbe5f85 --- /dev/null +++ b/llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp @@ -0,0 +1,853 @@ +//===-- X86Disassembler.cpp - Disassembler for x86 and x86_64 -------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file is part of the X86 Disassembler. +// It contains code to translate the data produced by the decoder into +// MCInsts. +// +// +// The X86 disassembler is a table-driven disassembler for the 16-, 32-, and +// 64-bit X86 instruction sets. The main decode sequence for an assembly +// instruction in this disassembler is: +// +// 1. Read the prefix bytes and determine the attributes of the instruction. +// These attributes, recorded in enum attributeBits +// (X86DisassemblerDecoderCommon.h), form a bitmask. The table CONTEXTS_SYM +// provides a mapping from bitmasks to contexts, which are represented by +// enum InstructionContext (ibid.). +// +// 2. Read the opcode, and determine what kind of opcode it is. The +// disassembler distinguishes four kinds of opcodes, which are enumerated in +// OpcodeType (X86DisassemblerDecoderCommon.h): one-byte (0xnn), two-byte +// (0x0f 0xnn), three-byte-38 (0x0f 0x38 0xnn), or three-byte-3a +// (0x0f 0x3a 0xnn). Mandatory prefixes are treated as part of the context. +// +// 3. Depending on the opcode type, look in one of four ClassDecision structures +// (X86DisassemblerDecoderCommon.h). Use the opcode class to determine which +// OpcodeDecision (ibid.) to look the opcode in. Look up the opcode, to get +// a ModRMDecision (ibid.). +// +// 4. Some instructions, such as escape opcodes or extended opcodes, or even +// instructions that have ModRM*Reg / ModRM*Mem forms in LLVM, need the +// ModR/M byte to complete decode. The ModRMDecision's type is an entry from +// ModRMDecisionType (X86DisassemblerDecoderCommon.h) that indicates if the +// ModR/M byte is required and how to interpret it. +// +// 5. After resolving the ModRMDecision, the disassembler has a unique ID +// of type InstrUID (X86DisassemblerDecoderCommon.h). Looking this ID up in +// INSTRUCTIONS_SYM yields the name of the instruction and the encodings and +// meanings of its operands. +// +// 6. For each operand, its encoding is an entry from OperandEncoding +// (X86DisassemblerDecoderCommon.h) and its type is an entry from +// OperandType (ibid.). The encoding indicates how to read it from the +// instruction; the type indicates how to interpret the value once it has +// been read. For example, a register operand could be stored in the R/M +// field of the ModR/M byte, the REG field of the ModR/M byte, or added to +// the main opcode. This is orthogonal from its meaning (an GPR or an XMM +// register, for instance). Given this information, the operands can be +// extracted and interpreted. +// +// 7. As the last step, the disassembler translates the instruction information +// and operands into a format understandable by the client - in this case, an +// MCInst for use by the MC infrastructure. +// +// The disassembler is broken broadly into two parts: the table emitter that +// emits the instruction decode tables discussed above during compilation, and +// the disassembler itself. The table emitter is documented in more detail in +// utils/TableGen/X86DisassemblerEmitter.h. +// +// X86Disassembler.cpp contains the code responsible for step 7, and for +// invoking the decoder to execute steps 1-6. +// X86DisassemblerDecoderCommon.h contains the definitions needed by both the +// table emitter and the disassembler. +// X86DisassemblerDecoder.h contains the public interface of the decoder, +// factored out into C for possible use by other projects. +// X86DisassemblerDecoder.c contains the source code of the decoder, which is +// responsible for steps 1-6. +// +//===----------------------------------------------------------------------===// + +#include "MCTargetDesc/X86BaseInfo.h" +#include "MCTargetDesc/X86MCTargetDesc.h" +#include "TargetInfo/X86TargetInfo.h" +#include "X86DisassemblerDecoder.h" +#include "llvm/MC/MCContext.h" +#include "llvm/MC/MCDisassembler/MCDisassembler.h" +#include "llvm/MC/MCExpr.h" +#include "llvm/MC/MCInst.h" +#include "llvm/MC/MCInstrInfo.h" +#include "llvm/MC/MCSubtargetInfo.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/TargetRegistry.h" +#include "llvm/Support/raw_ostream.h" + +using namespace llvm; +using namespace llvm::X86Disassembler; + +#define DEBUG_TYPE "x86-disassembler" + +void llvm::X86Disassembler::Debug(const char *file, unsigned line, + const char *s) { + dbgs() << file << ":" << line << ": " << s; +} + +StringRef llvm::X86Disassembler::GetInstrName(unsigned Opcode, + const void *mii) { + const MCInstrInfo *MII = static_cast<const MCInstrInfo *>(mii); + return MII->getName(Opcode); +} + +#define debug(s) LLVM_DEBUG(Debug(__FILE__, __LINE__, s)); + +namespace llvm { + +// Fill-ins to make the compiler happy. These constants are never actually +// assigned; they are just filler to make an automatically-generated switch +// statement work. +namespace X86 { + enum { + BX_SI = 500, + BX_DI = 501, + BP_SI = 502, + BP_DI = 503, + sib = 504, + sib64 = 505 + }; +} + +} + +static bool translateInstruction(MCInst &target, + InternalInstruction &source, + const MCDisassembler *Dis); + +namespace { + +/// Generic disassembler for all X86 platforms. All each platform class should +/// have to do is subclass the constructor, and provide a different +/// disassemblerMode value. +class X86GenericDisassembler : public MCDisassembler { + std::unique_ptr<const MCInstrInfo> MII; +public: + X86GenericDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx, + std::unique_ptr<const MCInstrInfo> MII); +public: + DecodeStatus getInstruction(MCInst &instr, uint64_t &size, + ArrayRef<uint8_t> Bytes, uint64_t Address, + raw_ostream &vStream, + raw_ostream &cStream) const override; + +private: + DisassemblerMode fMode; +}; + +} + +X86GenericDisassembler::X86GenericDisassembler( + const MCSubtargetInfo &STI, + MCContext &Ctx, + std::unique_ptr<const MCInstrInfo> MII) + : MCDisassembler(STI, Ctx), MII(std::move(MII)) { + const FeatureBitset &FB = STI.getFeatureBits(); + if (FB[X86::Mode16Bit]) { + fMode = MODE_16BIT; + return; + } else if (FB[X86::Mode32Bit]) { + fMode = MODE_32BIT; + return; + } else if (FB[X86::Mode64Bit]) { + fMode = MODE_64BIT; + return; + } + + llvm_unreachable("Invalid CPU mode"); +} + +namespace { +struct Region { + ArrayRef<uint8_t> Bytes; + uint64_t Base; + Region(ArrayRef<uint8_t> Bytes, uint64_t Base) : Bytes(Bytes), Base(Base) {} +}; +} // end anonymous namespace + +/// A callback function that wraps the readByte method from Region. +/// +/// @param Arg - The generic callback parameter. In this case, this should +/// be a pointer to a Region. +/// @param Byte - A pointer to the byte to be read. +/// @param Address - The address to be read. +static int regionReader(const void *Arg, uint8_t *Byte, uint64_t Address) { + auto *R = static_cast<const Region *>(Arg); + ArrayRef<uint8_t> Bytes = R->Bytes; + unsigned Index = Address - R->Base; + if (Bytes.size() <= Index) + return -1; + *Byte = Bytes[Index]; + return 0; +} + +/// logger - a callback function that wraps the operator<< method from +/// raw_ostream. +/// +/// @param arg - The generic callback parameter. This should be a pointe +/// to a raw_ostream. +/// @param log - A string to be logged. logger() adds a newline. +static void logger(void* arg, const char* log) { + if (!arg) + return; + + raw_ostream &vStream = *(static_cast<raw_ostream*>(arg)); + vStream << log << "\n"; +} + +// +// Public interface for the disassembler +// + +MCDisassembler::DecodeStatus X86GenericDisassembler::getInstruction( + MCInst &Instr, uint64_t &Size, ArrayRef<uint8_t> Bytes, uint64_t Address, + raw_ostream &VStream, raw_ostream &CStream) const { + CommentStream = &CStream; + + InternalInstruction InternalInstr; + + dlog_t LoggerFn = logger; + if (&VStream == &nulls()) + LoggerFn = nullptr; // Disable logging completely if it's going to nulls(). + + Region R(Bytes, Address); + + int Ret = decodeInstruction(&InternalInstr, regionReader, (const void *)&R, + LoggerFn, (void *)&VStream, + (const void *)MII.get(), Address, fMode); + + if (Ret) { + Size = InternalInstr.readerCursor - Address; + return Fail; + } else { + Size = InternalInstr.length; + bool Ret = translateInstruction(Instr, InternalInstr, this); + if (!Ret) { + unsigned Flags = X86::IP_NO_PREFIX; + if (InternalInstr.hasAdSize) + Flags |= X86::IP_HAS_AD_SIZE; + if (!InternalInstr.mandatoryPrefix) { + if (InternalInstr.hasOpSize) + Flags |= X86::IP_HAS_OP_SIZE; + if (InternalInstr.repeatPrefix == 0xf2) + Flags |= X86::IP_HAS_REPEAT_NE; + else if (InternalInstr.repeatPrefix == 0xf3 && + // It should not be 'pause' f3 90 + InternalInstr.opcode != 0x90) + Flags |= X86::IP_HAS_REPEAT; + if (InternalInstr.hasLockPrefix) + Flags |= X86::IP_HAS_LOCK; + } + Instr.setFlags(Flags); + } + return (!Ret) ? Success : Fail; + } +} + +// +// Private code that translates from struct InternalInstructions to MCInsts. +// + +/// translateRegister - Translates an internal register to the appropriate LLVM +/// register, and appends it as an operand to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param reg - The Reg to append. +static void translateRegister(MCInst &mcInst, Reg reg) { +#define ENTRY(x) X86::x, + static constexpr MCPhysReg llvmRegnums[] = {ALL_REGS}; +#undef ENTRY + + MCPhysReg llvmRegnum = llvmRegnums[reg]; + mcInst.addOperand(MCOperand::createReg(llvmRegnum)); +} + +/// tryAddingSymbolicOperand - trys to add a symbolic operand in place of the +/// immediate Value in the MCInst. +/// +/// @param Value - The immediate Value, has had any PC adjustment made by +/// the caller. +/// @param isBranch - If the instruction is a branch instruction +/// @param Address - The starting address of the instruction +/// @param Offset - The byte offset to this immediate in the instruction +/// @param Width - The byte width of this immediate in the instruction +/// +/// If the getOpInfo() function was set when setupForSymbolicDisassembly() was +/// called then that function is called to get any symbolic information for the +/// immediate in the instruction using the Address, Offset and Width. If that +/// returns non-zero then the symbolic information it returns is used to create +/// an MCExpr and that is added as an operand to the MCInst. If getOpInfo() +/// returns zero and isBranch is true then a symbol look up for immediate Value +/// is done and if a symbol is found an MCExpr is created with that, else +/// an MCExpr with the immediate Value is created. This function returns true +/// if it adds an operand to the MCInst and false otherwise. +static bool tryAddingSymbolicOperand(int64_t Value, bool isBranch, + uint64_t Address, uint64_t Offset, + uint64_t Width, MCInst &MI, + const MCDisassembler *Dis) { + return Dis->tryAddingSymbolicOperand(MI, Value, Address, isBranch, + Offset, Width); +} + +/// tryAddingPcLoadReferenceComment - trys to add a comment as to what is being +/// referenced by a load instruction with the base register that is the rip. +/// These can often be addresses in a literal pool. The Address of the +/// instruction and its immediate Value are used to determine the address +/// being referenced in the literal pool entry. The SymbolLookUp call back will +/// return a pointer to a literal 'C' string if the referenced address is an +/// address into a section with 'C' string literals. +static void tryAddingPcLoadReferenceComment(uint64_t Address, uint64_t Value, + const void *Decoder) { + const MCDisassembler *Dis = static_cast<const MCDisassembler*>(Decoder); + Dis->tryAddingPcLoadReferenceComment(Value, Address); +} + +static const uint8_t segmentRegnums[SEG_OVERRIDE_max] = { + 0, // SEG_OVERRIDE_NONE + X86::CS, + X86::SS, + X86::DS, + X86::ES, + X86::FS, + X86::GS +}; + +/// translateSrcIndex - Appends a source index operand to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param insn - The internal instruction. +static bool translateSrcIndex(MCInst &mcInst, InternalInstruction &insn) { + unsigned baseRegNo; + + if (insn.mode == MODE_64BIT) + baseRegNo = insn.hasAdSize ? X86::ESI : X86::RSI; + else if (insn.mode == MODE_32BIT) + baseRegNo = insn.hasAdSize ? X86::SI : X86::ESI; + else { + assert(insn.mode == MODE_16BIT); + baseRegNo = insn.hasAdSize ? X86::ESI : X86::SI; + } + MCOperand baseReg = MCOperand::createReg(baseRegNo); + mcInst.addOperand(baseReg); + + MCOperand segmentReg; + segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]); + mcInst.addOperand(segmentReg); + return false; +} + +/// translateDstIndex - Appends a destination index operand to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param insn - The internal instruction. + +static bool translateDstIndex(MCInst &mcInst, InternalInstruction &insn) { + unsigned baseRegNo; + + if (insn.mode == MODE_64BIT) + baseRegNo = insn.hasAdSize ? X86::EDI : X86::RDI; + else if (insn.mode == MODE_32BIT) + baseRegNo = insn.hasAdSize ? X86::DI : X86::EDI; + else { + assert(insn.mode == MODE_16BIT); + baseRegNo = insn.hasAdSize ? X86::EDI : X86::DI; + } + MCOperand baseReg = MCOperand::createReg(baseRegNo); + mcInst.addOperand(baseReg); + return false; +} + +/// translateImmediate - Appends an immediate operand to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param immediate - The immediate value to append. +/// @param operand - The operand, as stored in the descriptor table. +/// @param insn - The internal instruction. +static void translateImmediate(MCInst &mcInst, uint64_t immediate, + const OperandSpecifier &operand, + InternalInstruction &insn, + const MCDisassembler *Dis) { + // Sign-extend the immediate if necessary. + + OperandType type = (OperandType)operand.type; + + bool isBranch = false; + uint64_t pcrel = 0; + if (type == TYPE_REL) { + isBranch = true; + pcrel = insn.startLocation + + insn.immediateOffset + insn.immediateSize; + switch (operand.encoding) { + default: + break; + case ENCODING_Iv: + switch (insn.displacementSize) { + default: + break; + case 1: + if(immediate & 0x80) + immediate |= ~(0xffull); + break; + case 2: + if(immediate & 0x8000) + immediate |= ~(0xffffull); + break; + case 4: + if(immediate & 0x80000000) + immediate |= ~(0xffffffffull); + break; + case 8: + break; + } + break; + case ENCODING_IB: + if(immediate & 0x80) + immediate |= ~(0xffull); + break; + case ENCODING_IW: + if(immediate & 0x8000) + immediate |= ~(0xffffull); + break; + case ENCODING_ID: + if(immediate & 0x80000000) + immediate |= ~(0xffffffffull); + break; + } + } + // By default sign-extend all X86 immediates based on their encoding. + else if (type == TYPE_IMM) { + switch (operand.encoding) { + default: + break; + case ENCODING_IB: + if(immediate & 0x80) + immediate |= ~(0xffull); + break; + case ENCODING_IW: + if(immediate & 0x8000) + immediate |= ~(0xffffull); + break; + case ENCODING_ID: + if(immediate & 0x80000000) + immediate |= ~(0xffffffffull); + break; + case ENCODING_IO: + break; + } + } + + switch (type) { + case TYPE_XMM: + mcInst.addOperand(MCOperand::createReg(X86::XMM0 + (immediate >> 4))); + return; + case TYPE_YMM: + mcInst.addOperand(MCOperand::createReg(X86::YMM0 + (immediate >> 4))); + return; + case TYPE_ZMM: + mcInst.addOperand(MCOperand::createReg(X86::ZMM0 + (immediate >> 4))); + return; + default: + // operand is 64 bits wide. Do nothing. + break; + } + + if(!tryAddingSymbolicOperand(immediate + pcrel, isBranch, insn.startLocation, + insn.immediateOffset, insn.immediateSize, + mcInst, Dis)) + mcInst.addOperand(MCOperand::createImm(immediate)); + + if (type == TYPE_MOFFS) { + MCOperand segmentReg; + segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]); + mcInst.addOperand(segmentReg); + } +} + +/// translateRMRegister - Translates a register stored in the R/M field of the +/// ModR/M byte to its LLVM equivalent and appends it to an MCInst. +/// @param mcInst - The MCInst to append to. +/// @param insn - The internal instruction to extract the R/M field +/// from. +/// @return - 0 on success; -1 otherwise +static bool translateRMRegister(MCInst &mcInst, + InternalInstruction &insn) { + if (insn.eaBase == EA_BASE_sib || insn.eaBase == EA_BASE_sib64) { + debug("A R/M register operand may not have a SIB byte"); + return true; + } + + switch (insn.eaBase) { + default: + debug("Unexpected EA base register"); + return true; + case EA_BASE_NONE: + debug("EA_BASE_NONE for ModR/M base"); + return true; +#define ENTRY(x) case EA_BASE_##x: + ALL_EA_BASES +#undef ENTRY + debug("A R/M register operand may not have a base; " + "the operand must be a register."); + return true; +#define ENTRY(x) \ + case EA_REG_##x: \ + mcInst.addOperand(MCOperand::createReg(X86::x)); break; + ALL_REGS +#undef ENTRY + } + + return false; +} + +/// translateRMMemory - Translates a memory operand stored in the Mod and R/M +/// fields of an internal instruction (and possibly its SIB byte) to a memory +/// operand in LLVM's format, and appends it to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param insn - The instruction to extract Mod, R/M, and SIB fields +/// from. +/// @return - 0 on success; nonzero otherwise +static bool translateRMMemory(MCInst &mcInst, InternalInstruction &insn, + const MCDisassembler *Dis) { + // Addresses in an MCInst are represented as five operands: + // 1. basereg (register) The R/M base, or (if there is a SIB) the + // SIB base + // 2. scaleamount (immediate) 1, or (if there is a SIB) the specified + // scale amount + // 3. indexreg (register) x86_registerNONE, or (if there is a SIB) + // the index (which is multiplied by the + // scale amount) + // 4. displacement (immediate) 0, or the displacement if there is one + // 5. segmentreg (register) x86_registerNONE for now, but could be set + // if we have segment overrides + + MCOperand baseReg; + MCOperand scaleAmount; + MCOperand indexReg; + MCOperand displacement; + MCOperand segmentReg; + uint64_t pcrel = 0; + + if (insn.eaBase == EA_BASE_sib || insn.eaBase == EA_BASE_sib64) { + if (insn.sibBase != SIB_BASE_NONE) { + switch (insn.sibBase) { + default: + debug("Unexpected sibBase"); + return true; +#define ENTRY(x) \ + case SIB_BASE_##x: \ + baseReg = MCOperand::createReg(X86::x); break; + ALL_SIB_BASES +#undef ENTRY + } + } else { + baseReg = MCOperand::createReg(X86::NoRegister); + } + + if (insn.sibIndex != SIB_INDEX_NONE) { + switch (insn.sibIndex) { + default: + debug("Unexpected sibIndex"); + return true; +#define ENTRY(x) \ + case SIB_INDEX_##x: \ + indexReg = MCOperand::createReg(X86::x); break; + EA_BASES_32BIT + EA_BASES_64BIT + REGS_XMM + REGS_YMM + REGS_ZMM +#undef ENTRY + } + } else { + // Use EIZ/RIZ for a few ambiguous cases where the SIB byte is present, + // but no index is used and modrm alone should have been enough. + // -No base register in 32-bit mode. In 64-bit mode this is used to + // avoid rip-relative addressing. + // -Any base register used other than ESP/RSP/R12D/R12. Using these as a + // base always requires a SIB byte. + // -A scale other than 1 is used. + if (insn.sibScale != 1 || + (insn.sibBase == SIB_BASE_NONE && insn.mode != MODE_64BIT) || + (insn.sibBase != SIB_BASE_NONE && + insn.sibBase != SIB_BASE_ESP && insn.sibBase != SIB_BASE_RSP && + insn.sibBase != SIB_BASE_R12D && insn.sibBase != SIB_BASE_R12)) { + indexReg = MCOperand::createReg(insn.addressSize == 4 ? X86::EIZ : + X86::RIZ); + } else + indexReg = MCOperand::createReg(X86::NoRegister); + } + + scaleAmount = MCOperand::createImm(insn.sibScale); + } else { + switch (insn.eaBase) { + case EA_BASE_NONE: + if (insn.eaDisplacement == EA_DISP_NONE) { + debug("EA_BASE_NONE and EA_DISP_NONE for ModR/M base"); + return true; + } + if (insn.mode == MODE_64BIT){ + pcrel = insn.startLocation + + insn.displacementOffset + insn.displacementSize; + tryAddingPcLoadReferenceComment(insn.startLocation + + insn.displacementOffset, + insn.displacement + pcrel, Dis); + // Section 2.2.1.6 + baseReg = MCOperand::createReg(insn.addressSize == 4 ? X86::EIP : + X86::RIP); + } + else + baseReg = MCOperand::createReg(X86::NoRegister); + + indexReg = MCOperand::createReg(X86::NoRegister); + break; + case EA_BASE_BX_SI: + baseReg = MCOperand::createReg(X86::BX); + indexReg = MCOperand::createReg(X86::SI); + break; + case EA_BASE_BX_DI: + baseReg = MCOperand::createReg(X86::BX); + indexReg = MCOperand::createReg(X86::DI); + break; + case EA_BASE_BP_SI: + baseReg = MCOperand::createReg(X86::BP); + indexReg = MCOperand::createReg(X86::SI); + break; + case EA_BASE_BP_DI: + baseReg = MCOperand::createReg(X86::BP); + indexReg = MCOperand::createReg(X86::DI); + break; + default: + indexReg = MCOperand::createReg(X86::NoRegister); + switch (insn.eaBase) { + default: + debug("Unexpected eaBase"); + return true; + // Here, we will use the fill-ins defined above. However, + // BX_SI, BX_DI, BP_SI, and BP_DI are all handled above and + // sib and sib64 were handled in the top-level if, so they're only + // placeholders to keep the compiler happy. +#define ENTRY(x) \ + case EA_BASE_##x: \ + baseReg = MCOperand::createReg(X86::x); break; + ALL_EA_BASES +#undef ENTRY +#define ENTRY(x) case EA_REG_##x: + ALL_REGS +#undef ENTRY + debug("A R/M memory operand may not be a register; " + "the base field must be a base."); + return true; + } + } + + scaleAmount = MCOperand::createImm(1); + } + + displacement = MCOperand::createImm(insn.displacement); + + segmentReg = MCOperand::createReg(segmentRegnums[insn.segmentOverride]); + + mcInst.addOperand(baseReg); + mcInst.addOperand(scaleAmount); + mcInst.addOperand(indexReg); + if(!tryAddingSymbolicOperand(insn.displacement + pcrel, false, + insn.startLocation, insn.displacementOffset, + insn.displacementSize, mcInst, Dis)) + mcInst.addOperand(displacement); + mcInst.addOperand(segmentReg); + return false; +} + +/// translateRM - Translates an operand stored in the R/M (and possibly SIB) +/// byte of an instruction to LLVM form, and appends it to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param operand - The operand, as stored in the descriptor table. +/// @param insn - The instruction to extract Mod, R/M, and SIB fields +/// from. +/// @return - 0 on success; nonzero otherwise +static bool translateRM(MCInst &mcInst, const OperandSpecifier &operand, + InternalInstruction &insn, const MCDisassembler *Dis) { + switch (operand.type) { + default: + debug("Unexpected type for a R/M operand"); + return true; + case TYPE_R8: + case TYPE_R16: + case TYPE_R32: + case TYPE_R64: + case TYPE_Rv: + case TYPE_MM64: + case TYPE_XMM: + case TYPE_YMM: + case TYPE_ZMM: + case TYPE_VK_PAIR: + case TYPE_VK: + case TYPE_DEBUGREG: + case TYPE_CONTROLREG: + case TYPE_BNDR: + return translateRMRegister(mcInst, insn); + case TYPE_M: + case TYPE_MVSIBX: + case TYPE_MVSIBY: + case TYPE_MVSIBZ: + return translateRMMemory(mcInst, insn, Dis); + } +} + +/// translateFPRegister - Translates a stack position on the FPU stack to its +/// LLVM form, and appends it to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param stackPos - The stack position to translate. +static void translateFPRegister(MCInst &mcInst, + uint8_t stackPos) { + mcInst.addOperand(MCOperand::createReg(X86::ST0 + stackPos)); +} + +/// translateMaskRegister - Translates a 3-bit mask register number to +/// LLVM form, and appends it to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param maskRegNum - Number of mask register from 0 to 7. +/// @return - false on success; true otherwise. +static bool translateMaskRegister(MCInst &mcInst, + uint8_t maskRegNum) { + if (maskRegNum >= 8) { + debug("Invalid mask register number"); + return true; + } + + mcInst.addOperand(MCOperand::createReg(X86::K0 + maskRegNum)); + return false; +} + +/// translateOperand - Translates an operand stored in an internal instruction +/// to LLVM's format and appends it to an MCInst. +/// +/// @param mcInst - The MCInst to append to. +/// @param operand - The operand, as stored in the descriptor table. +/// @param insn - The internal instruction. +/// @return - false on success; true otherwise. +static bool translateOperand(MCInst &mcInst, const OperandSpecifier &operand, + InternalInstruction &insn, + const MCDisassembler *Dis) { + switch (operand.encoding) { + default: + debug("Unhandled operand encoding during translation"); + return true; + case ENCODING_REG: + translateRegister(mcInst, insn.reg); + return false; + case ENCODING_WRITEMASK: + return translateMaskRegister(mcInst, insn.writemask); + CASE_ENCODING_RM: + CASE_ENCODING_VSIB: + return translateRM(mcInst, operand, insn, Dis); + case ENCODING_IB: + case ENCODING_IW: + case ENCODING_ID: + case ENCODING_IO: + case ENCODING_Iv: + case ENCODING_Ia: + translateImmediate(mcInst, + insn.immediates[insn.numImmediatesTranslated++], + operand, + insn, + Dis); + return false; + case ENCODING_IRC: + mcInst.addOperand(MCOperand::createImm(insn.RC)); + return false; + case ENCODING_SI: + return translateSrcIndex(mcInst, insn); + case ENCODING_DI: + return translateDstIndex(mcInst, insn); + case ENCODING_RB: + case ENCODING_RW: + case ENCODING_RD: + case ENCODING_RO: + case ENCODING_Rv: + translateRegister(mcInst, insn.opcodeRegister); + return false; + case ENCODING_CC: + mcInst.addOperand(MCOperand::createImm(insn.immediates[1])); + return false; + case ENCODING_FP: + translateFPRegister(mcInst, insn.modRM & 7); + return false; + case ENCODING_VVVV: + translateRegister(mcInst, insn.vvvv); + return false; + case ENCODING_DUP: + return translateOperand(mcInst, insn.operands[operand.type - TYPE_DUP0], + insn, Dis); + } +} + +/// translateInstruction - Translates an internal instruction and all its +/// operands to an MCInst. +/// +/// @param mcInst - The MCInst to populate with the instruction's data. +/// @param insn - The internal instruction. +/// @return - false on success; true otherwise. +static bool translateInstruction(MCInst &mcInst, + InternalInstruction &insn, + const MCDisassembler *Dis) { + if (!insn.spec) { + debug("Instruction has no specification"); + return true; + } + + mcInst.clear(); + mcInst.setOpcode(insn.instructionID); + // If when reading the prefix bytes we determined the overlapping 0xf2 or 0xf3 + // prefix bytes should be disassembled as xrelease and xacquire then set the + // opcode to those instead of the rep and repne opcodes. + if (insn.xAcquireRelease) { + if(mcInst.getOpcode() == X86::REP_PREFIX) + mcInst.setOpcode(X86::XRELEASE_PREFIX); + else if(mcInst.getOpcode() == X86::REPNE_PREFIX) + mcInst.setOpcode(X86::XACQUIRE_PREFIX); + } + + insn.numImmediatesTranslated = 0; + + for (const auto &Op : insn.operands) { + if (Op.encoding != ENCODING_NONE) { + if (translateOperand(mcInst, Op, insn, Dis)) { + return true; + } + } + } + + return false; +} + +static MCDisassembler *createX86Disassembler(const Target &T, + const MCSubtargetInfo &STI, + MCContext &Ctx) { + std::unique_ptr<const MCInstrInfo> MII(T.createMCInstrInfo()); + return new X86GenericDisassembler(STI, Ctx, std::move(MII)); +} + +extern "C" void LLVMInitializeX86Disassembler() { + // Register the disassembler. + TargetRegistry::RegisterMCDisassembler(getTheX86_32Target(), + createX86Disassembler); + TargetRegistry::RegisterMCDisassembler(getTheX86_64Target(), + createX86Disassembler); +} |