//===------ PPCDisassembler.cpp - Disassembler for PowerPC ------*- C++ -*-===// // // 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 // //===----------------------------------------------------------------------===// #include "MCTargetDesc/PPCMCTargetDesc.h" #include "TargetInfo/PowerPCTargetInfo.h" #include "llvm/MC/MCDecoderOps.h" #include "llvm/MC/MCDisassembler/MCDisassembler.h" #include "llvm/MC/MCInst.h" #include "llvm/MC/MCSubtargetInfo.h" #include "llvm/MC/TargetRegistry.h" #include "llvm/Support/Endian.h" using namespace llvm; DEFINE_PPC_REGCLASSES #define DEBUG_TYPE "ppc-disassembler" typedef MCDisassembler::DecodeStatus DecodeStatus; namespace { class PPCDisassembler : public MCDisassembler { bool IsLittleEndian; public: PPCDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx, bool IsLittleEndian) : MCDisassembler(STI, Ctx), IsLittleEndian(IsLittleEndian) {} DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size, ArrayRef Bytes, uint64_t Address, raw_ostream &CStream) const override; }; } // end anonymous namespace static MCDisassembler *createPPCDisassembler(const Target &T, const MCSubtargetInfo &STI, MCContext &Ctx) { return new PPCDisassembler(STI, Ctx, /*IsLittleEndian=*/false); } static MCDisassembler *createPPCLEDisassembler(const Target &T, const MCSubtargetInfo &STI, MCContext &Ctx) { return new PPCDisassembler(STI, Ctx, /*IsLittleEndian=*/true); } extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializePowerPCDisassembler() { // Register the disassembler for each target. TargetRegistry::RegisterMCDisassembler(getThePPC32Target(), createPPCDisassembler); TargetRegistry::RegisterMCDisassembler(getThePPC32LETarget(), createPPCLEDisassembler); TargetRegistry::RegisterMCDisassembler(getThePPC64Target(), createPPCDisassembler); TargetRegistry::RegisterMCDisassembler(getThePPC64LETarget(), createPPCLEDisassembler); } static DecodeStatus decodeCondBrTarget(MCInst &Inst, unsigned Imm, uint64_t /*Address*/, const MCDisassembler * /*Decoder*/) { Inst.addOperand(MCOperand::createImm(SignExtend32<14>(Imm))); return MCDisassembler::Success; } static DecodeStatus decodeDirectBrTarget(MCInst &Inst, unsigned Imm, uint64_t /*Address*/, const MCDisassembler * /*Decoder*/) { int32_t Offset = SignExtend32<24>(Imm); Inst.addOperand(MCOperand::createImm(Offset)); return MCDisassembler::Success; } // FIXME: These can be generated by TableGen from the existing register // encoding values! template static DecodeStatus decodeRegisterClass(MCInst &Inst, uint64_t RegNo, const MCPhysReg (&Regs)[N]) { if (RegNo >= N) return MCDisassembler::Fail; Inst.addOperand(MCOperand::createReg(Regs[RegNo])); return MCDisassembler::Success; } static DecodeStatus DecodeCRRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, CRRegs); } static DecodeStatus DecodeCRBITRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, CRBITRegs); } static DecodeStatus DecodeF4RCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, FRegs); } static DecodeStatus DecodeF8RCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, FRegs); } static DecodeStatus DecodeFpRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { if (RegNo > 30 || (RegNo & 1)) return MCDisassembler::Fail; return decodeRegisterClass(Inst, RegNo >> 1, FpRegs); } static DecodeStatus DecodeVFRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, VFRegs); } static DecodeStatus DecodeVRRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, VRegs); } static DecodeStatus DecodeVSRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, VSRegs); } static DecodeStatus DecodeVSFRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, VSFRegs); } static DecodeStatus DecodeVSSRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, VSSRegs); } static DecodeStatus DecodeGPRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, RRegs); } static DecodeStatus DecodeGPRC_NOR0RegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, RRegsNoR0); } static DecodeStatus DecodeG8RCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, XRegs); } static DecodeStatus DecodeG8pRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, XRegs); } static DecodeStatus DecodeG8RC_NOX0RegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, XRegsNoX0); } #define DecodePointerLikeRegClass0 DecodeGPRCRegisterClass #define DecodePointerLikeRegClass1 DecodeGPRC_NOR0RegisterClass static DecodeStatus DecodeSPERCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, SPERegs); } static DecodeStatus DecodeACCRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, ACCRegs); } static DecodeStatus DecodeWACCRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const void *Decoder) { return decodeRegisterClass(Inst, RegNo, WACCRegs); } static DecodeStatus DecodeWACC_HIRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const void *Decoder) { return decodeRegisterClass(Inst, RegNo, WACC_HIRegs); } // TODO: Make this function static when the register class is used by a new // instruction. DecodeStatus DecodeDMRROWRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const void *Decoder) { return decodeRegisterClass(Inst, RegNo, DMRROWRegs); } static DecodeStatus DecodeDMRROWpRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const void *Decoder) { return decodeRegisterClass(Inst, RegNo, DMRROWpRegs); } static DecodeStatus DecodeDMRRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const void *Decoder) { return decodeRegisterClass(Inst, RegNo, DMRRegs); } // TODO: Make this function static when the register class is used by a new // instruction. DecodeStatus DecodeDMRpRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const void *Decoder) { return decodeRegisterClass(Inst, RegNo, DMRpRegs); } static DecodeStatus DecodeVSRpRCRegisterClass(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { return decodeRegisterClass(Inst, RegNo, VSRpRegs); } #define DecodeQSRCRegisterClass DecodeQFRCRegisterClass #define DecodeQBRCRegisterClass DecodeQFRCRegisterClass template static DecodeStatus decodeUImmOperand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { if (!isUInt(Imm)) return MCDisassembler::Fail; Inst.addOperand(MCOperand::createImm(Imm)); return MCDisassembler::Success; } template static DecodeStatus decodeSImmOperand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { if (!isUInt(Imm)) return MCDisassembler::Fail; Inst.addOperand(MCOperand::createImm(SignExtend64(Imm))); return MCDisassembler::Success; } static DecodeStatus decodeImmZeroOperand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { if (Imm != 0) return MCDisassembler::Fail; Inst.addOperand(MCOperand::createImm(Imm)); return MCDisassembler::Success; } static DecodeStatus decodeVSRpEvenOperands(MCInst &Inst, uint64_t RegNo, uint64_t Address, const MCDisassembler *Decoder) { if (RegNo & 1) return MCDisassembler::Fail; Inst.addOperand(MCOperand::createReg(VSRpRegs[RegNo >> 1])); return MCDisassembler::Success; } static DecodeStatus decodeDispRIXOperand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // The rix displacement is an immediate shifted by 2 Inst.addOperand(MCOperand::createImm(SignExtend64<16>(Imm << 2))); return MCDisassembler::Success; } static DecodeStatus decodeDispRIHashOperand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // Decode the disp field for a hash store or hash check operation. // The field is composed of an immediate value that is 6 bits // and covers the range -8 to -512. The immediate is always negative and 2s // complement which is why we sign extend a 7 bit value. const int64_t Disp = SignExtend64<7>((Imm & 0x3F) + 64) * 8; Inst.addOperand(MCOperand::createImm(Disp)); return MCDisassembler::Success; } static DecodeStatus decodeDispRIX16Operand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // The rix16 displacement has 12-bits which are shifted by 4. Inst.addOperand(MCOperand::createImm(SignExtend64<16>(Imm << 4))); return MCDisassembler::Success; } static DecodeStatus decodeDispSPE8Operand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // Decode the dispSPE8 field, which has 5-bits, 8-byte aligned. uint64_t Disp = Imm & 0x1F; Inst.addOperand(MCOperand::createImm(Disp << 3)); return MCDisassembler::Success; } static DecodeStatus decodeDispSPE4Operand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // Decode the dispSPE8 field, which has 5-bits, 4-byte aligned. uint64_t Disp = Imm & 0x1F; Inst.addOperand(MCOperand::createImm(Disp << 2)); return MCDisassembler::Success; } static DecodeStatus decodeDispSPE2Operand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // Decode the dispSPE8 field, which has 5-bits, 2-byte aligned. uint64_t Disp = Imm & 0x1F; Inst.addOperand(MCOperand::createImm(Disp << 1)); return MCDisassembler::Success; } static DecodeStatus decodeCRBitMOperand(MCInst &Inst, uint64_t Imm, int64_t Address, const MCDisassembler *Decoder) { // The cr bit encoding is 0x80 >> cr_reg_num. unsigned Zeros = llvm::countr_zero(Imm); if (Zeros >= 8) return MCDisassembler::Fail; Inst.addOperand(MCOperand::createReg(CRRegs[7 - Zeros])); return MCDisassembler::Success; } #include "PPCGenDisassemblerTables.inc" DecodeStatus PPCDisassembler::getInstruction(MCInst &MI, uint64_t &Size, ArrayRef Bytes, uint64_t Address, raw_ostream &CS) const { auto *ReadFunc = IsLittleEndian ? support::endian::read32le : support::endian::read32be; // If this is an 8-byte prefixed instruction, handle it here. // Note: prefixed instructions aren't technically 8-byte entities - the prefix // appears in memory at an address 4 bytes prior to that of the base // instruction regardless of endianness. So we read the two pieces and // rebuild the 8-byte instruction. // TODO: In this function we call decodeInstruction several times with // different decoder tables. It may be possible to only call once by // looking at the top 6 bits of the instruction. if (STI.hasFeature(PPC::FeaturePrefixInstrs) && Bytes.size() >= 8) { uint32_t Prefix = ReadFunc(Bytes.data()); uint32_t BaseInst = ReadFunc(Bytes.data() + 4); uint64_t Inst = BaseInst | (uint64_t)Prefix << 32; DecodeStatus result = decodeInstruction(DecoderTable64, MI, Inst, Address, this, STI); if (result != MCDisassembler::Fail) { Size = 8; return result; } } // Get the four bytes of the instruction. Size = 4; if (Bytes.size() < 4) { Size = 0; return MCDisassembler::Fail; } // Read the instruction in the proper endianness. uint64_t Inst = ReadFunc(Bytes.data()); if (STI.hasFeature(PPC::FeatureSPE)) { DecodeStatus result = decodeInstruction(DecoderTableSPE32, MI, Inst, Address, this, STI); if (result != MCDisassembler::Fail) return result; } return decodeInstruction(DecoderTable32, MI, Inst, Address, this, STI); }