//===-- MipsAsmBackend.cpp - Mips Asm Backend ----------------------------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the MipsAsmBackend class. // //===----------------------------------------------------------------------===// // #include "MCTargetDesc/MipsFixupKinds.h" #include "MCTargetDesc/MipsAsmBackend.h" #include "MCTargetDesc/MipsMCTargetDesc.h" #include "llvm/MC/MCAsmBackend.h" #include "llvm/MC/MCAssembler.h" #include "llvm/MC/MCContext.h" #include "llvm/MC/MCDirectives.h" #include "llvm/MC/MCELFObjectWriter.h" #include "llvm/MC/MCFixupKindInfo.h" #include "llvm/MC/MCObjectWriter.h" #include "llvm/MC/MCSubtargetInfo.h" #include "llvm/Support/ErrorHandling.h" #include "llvm/Support/MathExtras.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; // Prepare value for the target space for it static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value, MCContext *Ctx = nullptr) { unsigned Kind = Fixup.getKind(); // Add/subtract and shift switch (Kind) { default: return 0; case FK_Data_2: case FK_GPRel_4: case FK_Data_4: case FK_Data_8: case Mips::fixup_Mips_LO16: case Mips::fixup_Mips_GPREL16: case Mips::fixup_Mips_GPOFF_HI: case Mips::fixup_Mips_GPOFF_LO: case Mips::fixup_Mips_GOT_PAGE: case Mips::fixup_Mips_GOT_OFST: case Mips::fixup_Mips_GOT_DISP: case Mips::fixup_Mips_GOT_LO16: case Mips::fixup_Mips_CALL_LO16: case Mips::fixup_MICROMIPS_LO16: case Mips::fixup_MICROMIPS_GOT_PAGE: case Mips::fixup_MICROMIPS_GOT_OFST: case Mips::fixup_MICROMIPS_GOT_DISP: case Mips::fixup_MIPS_PCLO16: break; case Mips::fixup_Mips_PC16: // So far we are only using this type for branches. // For branches we start 1 instruction after the branch // so the displacement will be one instruction size less. Value -= 4; // The displacement is then divided by 4 to give us an 18 bit // address range. Forcing a signed division because Value can be negative. Value = (int64_t)Value / 4; // We now check if Value can be encoded as a 16-bit signed immediate. if (!isIntN(16, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC16 fixup"); break; case Mips::fixup_MIPS_PC19_S2: // Forcing a signed division because Value can be negative. Value = (int64_t)Value / 4; // We now check if Value can be encoded as a 19-bit signed immediate. if (!isIntN(19, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC19 fixup"); break; case Mips::fixup_Mips_26: // So far we are only using this type for jumps. // The displacement is then divided by 4 to give us an 28 bit // address range. Value >>= 2; break; case Mips::fixup_Mips_HI16: case Mips::fixup_Mips_GOT_Local: case Mips::fixup_Mips_GOT_HI16: case Mips::fixup_Mips_CALL_HI16: case Mips::fixup_MICROMIPS_HI16: case Mips::fixup_MIPS_PCHI16: // Get the 2nd 16-bits. Also add 1 if bit 15 is 1. Value = ((Value + 0x8000) >> 16) & 0xffff; break; case Mips::fixup_Mips_HIGHER: // Get the 3rd 16-bits. Value = ((Value + 0x80008000LL) >> 32) & 0xffff; break; case Mips::fixup_Mips_HIGHEST: // Get the 4th 16-bits. Value = ((Value + 0x800080008000LL) >> 48) & 0xffff; break; case Mips::fixup_MICROMIPS_26_S1: Value >>= 1; break; case Mips::fixup_MICROMIPS_PC7_S1: Value -= 4; // Forcing a signed division because Value can be negative. Value = (int64_t) Value / 2; // We now check if Value can be encoded as a 7-bit signed immediate. if (!isIntN(7, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC7 fixup"); break; case Mips::fixup_MICROMIPS_PC10_S1: Value -= 2; // Forcing a signed division because Value can be negative. Value = (int64_t) Value / 2; // We now check if Value can be encoded as a 10-bit signed immediate. if (!isIntN(10, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC10 fixup"); break; case Mips::fixup_MICROMIPS_PC16_S1: Value -= 4; // Forcing a signed division because Value can be negative. Value = (int64_t)Value / 2; // We now check if Value can be encoded as a 16-bit signed immediate. if (!isIntN(16, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC16 fixup"); break; case Mips::fixup_MIPS_PC18_S3: // Forcing a signed division because Value can be negative. Value = (int64_t)Value / 8; // We now check if Value can be encoded as a 18-bit signed immediate. if (!isIntN(18, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC18 fixup"); break; case Mips::fixup_MIPS_PC21_S2: Value -= 4; // Forcing a signed division because Value can be negative. Value = (int64_t) Value / 4; // We now check if Value can be encoded as a 21-bit signed immediate. if (!isIntN(21, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC21 fixup"); break; case Mips::fixup_MIPS_PC26_S2: Value -= 4; // Forcing a signed division because Value can be negative. Value = (int64_t) Value / 4; // We now check if Value can be encoded as a 26-bit signed immediate. if (!isIntN(26, Value) && Ctx) Ctx->FatalError(Fixup.getLoc(), "out of range PC26 fixup"); break; } return Value; } MCObjectWriter * MipsAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const { return createMipsELFObjectWriter(OS, MCELFObjectTargetWriter::getOSABI(OSType), IsLittle, Is64Bit); } // Little-endian fixup data byte ordering: // mips32r2: a | b | x | x // microMIPS: x | x | a | b static bool needsMMLEByteOrder(unsigned Kind) { return Kind != Mips::fixup_MICROMIPS_PC10_S1 && Kind >= Mips::fixup_MICROMIPS_26_S1 && Kind < Mips::LastTargetFixupKind; } // Calculate index for microMIPS specific little endian byte order static unsigned calculateMMLEIndex(unsigned i) { assert(i <= 3 && "Index out of range!"); return (1 - i / 2) * 2 + i % 2; } /// ApplyFixup - Apply the \p Value for given \p Fixup into the provided /// data fragment, at the offset specified by the fixup and following the /// fixup kind as appropriate. void MipsAsmBackend::applyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, uint64_t Value, bool IsPCRel) const { MCFixupKind Kind = Fixup.getKind(); Value = adjustFixupValue(Fixup, Value); if (!Value) return; // Doesn't change encoding. // Where do we start in the object unsigned Offset = Fixup.getOffset(); // Number of bytes we need to fixup unsigned NumBytes = (getFixupKindInfo(Kind).TargetSize + 7) / 8; // Used to point to big endian bytes unsigned FullSize; switch ((unsigned)Kind) { case FK_Data_2: case Mips::fixup_Mips_16: case Mips::fixup_MICROMIPS_PC10_S1: FullSize = 2; break; case FK_Data_8: case Mips::fixup_Mips_64: FullSize = 8; break; case FK_Data_4: default: FullSize = 4; break; } // Grab current value, if any, from bits. uint64_t CurVal = 0; bool microMipsLEByteOrder = needsMMLEByteOrder((unsigned) Kind); for (unsigned i = 0; i != NumBytes; ++i) { unsigned Idx = IsLittle ? (microMipsLEByteOrder ? calculateMMLEIndex(i) : i) : (FullSize - 1 - i); CurVal |= (uint64_t)((uint8_t)Data[Offset + Idx]) << (i*8); } uint64_t Mask = ((uint64_t)(-1) >> (64 - getFixupKindInfo(Kind).TargetSize)); CurVal |= Value & Mask; // Write out the fixed up bytes back to the code/data bits. for (unsigned i = 0; i != NumBytes; ++i) { unsigned Idx = IsLittle ? (microMipsLEByteOrder ? calculateMMLEIndex(i) : i) : (FullSize - 1 - i); Data[Offset + Idx] = (uint8_t)((CurVal >> (i*8)) & 0xff); } } const MCFixupKindInfo &MipsAsmBackend:: getFixupKindInfo(MCFixupKind Kind) const { const static MCFixupKindInfo LittleEndianInfos[Mips::NumTargetFixupKinds] = { // This table *must* be in same the order of fixup_* kinds in // MipsFixupKinds.h. // // name offset bits flags { "fixup_Mips_16", 0, 16, 0 }, { "fixup_Mips_32", 0, 32, 0 }, { "fixup_Mips_REL32", 0, 32, 0 }, { "fixup_Mips_26", 0, 26, 0 }, { "fixup_Mips_HI16", 0, 16, 0 }, { "fixup_Mips_LO16", 0, 16, 0 }, { "fixup_Mips_GPREL16", 0, 16, 0 }, { "fixup_Mips_LITERAL", 0, 16, 0 }, { "fixup_Mips_GOT_Global", 0, 16, 0 }, { "fixup_Mips_GOT_Local", 0, 16, 0 }, { "fixup_Mips_PC16", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_Mips_CALL16", 0, 16, 0 }, { "fixup_Mips_GPREL32", 0, 32, 0 }, { "fixup_Mips_SHIFT5", 6, 5, 0 }, { "fixup_Mips_SHIFT6", 6, 5, 0 }, { "fixup_Mips_64", 0, 64, 0 }, { "fixup_Mips_TLSGD", 0, 16, 0 }, { "fixup_Mips_GOTTPREL", 0, 16, 0 }, { "fixup_Mips_TPREL_HI", 0, 16, 0 }, { "fixup_Mips_TPREL_LO", 0, 16, 0 }, { "fixup_Mips_TLSLDM", 0, 16, 0 }, { "fixup_Mips_DTPREL_HI", 0, 16, 0 }, { "fixup_Mips_DTPREL_LO", 0, 16, 0 }, { "fixup_Mips_Branch_PCRel", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_Mips_GPOFF_HI", 0, 16, 0 }, { "fixup_Mips_GPOFF_LO", 0, 16, 0 }, { "fixup_Mips_GOT_PAGE", 0, 16, 0 }, { "fixup_Mips_GOT_OFST", 0, 16, 0 }, { "fixup_Mips_GOT_DISP", 0, 16, 0 }, { "fixup_Mips_HIGHER", 0, 16, 0 }, { "fixup_Mips_HIGHEST", 0, 16, 0 }, { "fixup_Mips_GOT_HI16", 0, 16, 0 }, { "fixup_Mips_GOT_LO16", 0, 16, 0 }, { "fixup_Mips_CALL_HI16", 0, 16, 0 }, { "fixup_Mips_CALL_LO16", 0, 16, 0 }, { "fixup_Mips_PC18_S3", 0, 18, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PC19_S2", 0, 19, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PC21_S2", 0, 21, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PC26_S2", 0, 26, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PCHI16", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PCLO16", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_26_S1", 0, 26, 0 }, { "fixup_MICROMIPS_HI16", 0, 16, 0 }, { "fixup_MICROMIPS_LO16", 0, 16, 0 }, { "fixup_MICROMIPS_GOT16", 0, 16, 0 }, { "fixup_MICROMIPS_PC7_S1", 0, 7, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_PC10_S1", 0, 10, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_PC16_S1", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_CALL16", 0, 16, 0 }, { "fixup_MICROMIPS_GOT_DISP", 0, 16, 0 }, { "fixup_MICROMIPS_GOT_PAGE", 0, 16, 0 }, { "fixup_MICROMIPS_GOT_OFST", 0, 16, 0 }, { "fixup_MICROMIPS_TLS_GD", 0, 16, 0 }, { "fixup_MICROMIPS_TLS_LDM", 0, 16, 0 }, { "fixup_MICROMIPS_TLS_DTPREL_HI16", 0, 16, 0 }, { "fixup_MICROMIPS_TLS_DTPREL_LO16", 0, 16, 0 }, { "fixup_MICROMIPS_TLS_TPREL_HI16", 0, 16, 0 }, { "fixup_MICROMIPS_TLS_TPREL_LO16", 0, 16, 0 } }; const static MCFixupKindInfo BigEndianInfos[Mips::NumTargetFixupKinds] = { // This table *must* be in same the order of fixup_* kinds in // MipsFixupKinds.h. // // name offset bits flags { "fixup_Mips_16", 16, 16, 0 }, { "fixup_Mips_32", 0, 32, 0 }, { "fixup_Mips_REL32", 0, 32, 0 }, { "fixup_Mips_26", 6, 26, 0 }, { "fixup_Mips_HI16", 16, 16, 0 }, { "fixup_Mips_LO16", 16, 16, 0 }, { "fixup_Mips_GPREL16", 16, 16, 0 }, { "fixup_Mips_LITERAL", 16, 16, 0 }, { "fixup_Mips_GOT_Global", 16, 16, 0 }, { "fixup_Mips_GOT_Local", 16, 16, 0 }, { "fixup_Mips_PC16", 16, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_Mips_CALL16", 16, 16, 0 }, { "fixup_Mips_GPREL32", 0, 32, 0 }, { "fixup_Mips_SHIFT5", 21, 5, 0 }, { "fixup_Mips_SHIFT6", 21, 5, 0 }, { "fixup_Mips_64", 0, 64, 0 }, { "fixup_Mips_TLSGD", 16, 16, 0 }, { "fixup_Mips_GOTTPREL", 16, 16, 0 }, { "fixup_Mips_TPREL_HI", 16, 16, 0 }, { "fixup_Mips_TPREL_LO", 16, 16, 0 }, { "fixup_Mips_TLSLDM", 16, 16, 0 }, { "fixup_Mips_DTPREL_HI", 16, 16, 0 }, { "fixup_Mips_DTPREL_LO", 16, 16, 0 }, { "fixup_Mips_Branch_PCRel",16, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_Mips_GPOFF_HI", 16, 16, 0 }, { "fixup_Mips_GPOFF_LO", 16, 16, 0 }, { "fixup_Mips_GOT_PAGE", 16, 16, 0 }, { "fixup_Mips_GOT_OFST", 16, 16, 0 }, { "fixup_Mips_GOT_DISP", 16, 16, 0 }, { "fixup_Mips_HIGHER", 16, 16, 0 }, { "fixup_Mips_HIGHEST", 16, 16, 0 }, { "fixup_Mips_GOT_HI16", 16, 16, 0 }, { "fixup_Mips_GOT_LO16", 16, 16, 0 }, { "fixup_Mips_CALL_HI16", 16, 16, 0 }, { "fixup_Mips_CALL_LO16", 16, 16, 0 }, { "fixup_Mips_PC18_S3", 14, 18, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PC19_S2", 13, 19, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PC21_S2", 11, 21, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PC26_S2", 6, 26, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PCHI16", 16, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MIPS_PCLO16", 16, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_26_S1", 6, 26, 0 }, { "fixup_MICROMIPS_HI16", 16, 16, 0 }, { "fixup_MICROMIPS_LO16", 16, 16, 0 }, { "fixup_MICROMIPS_GOT16", 16, 16, 0 }, { "fixup_MICROMIPS_PC7_S1", 9, 7, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_PC10_S1", 6, 10, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_PC16_S1",16, 16, MCFixupKindInfo::FKF_IsPCRel }, { "fixup_MICROMIPS_CALL16", 16, 16, 0 }, { "fixup_MICROMIPS_GOT_DISP", 16, 16, 0 }, { "fixup_MICROMIPS_GOT_PAGE", 16, 16, 0 }, { "fixup_MICROMIPS_GOT_OFST", 16, 16, 0 }, { "fixup_MICROMIPS_TLS_GD", 16, 16, 0 }, { "fixup_MICROMIPS_TLS_LDM", 16, 16, 0 }, { "fixup_MICROMIPS_TLS_DTPREL_HI16", 16, 16, 0 }, { "fixup_MICROMIPS_TLS_DTPREL_LO16", 16, 16, 0 }, { "fixup_MICROMIPS_TLS_TPREL_HI16", 16, 16, 0 }, { "fixup_MICROMIPS_TLS_TPREL_LO16", 16, 16, 0 } }; if (Kind < FirstTargetFixupKind) return MCAsmBackend::getFixupKindInfo(Kind); assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && "Invalid kind!"); if (IsLittle) return LittleEndianInfos[Kind - FirstTargetFixupKind]; return BigEndianInfos[Kind - FirstTargetFixupKind]; } /// WriteNopData - Write an (optimal) nop sequence of Count bytes /// to the given output. If the target cannot generate such a sequence, /// it should return an error. /// /// \return - True on success. bool MipsAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const { // Check for a less than instruction size number of bytes // FIXME: 16 bit instructions are not handled yet here. // We shouldn't be using a hard coded number for instruction size. // If the count is not 4-byte aligned, we must be writing data into the text // section (otherwise we have unaligned instructions, and thus have far // bigger problems), so just write zeros instead. for (uint64_t i = 0, e = Count % 4; i != e; ++i) OW->Write8(0); uint64_t NumNops = Count / 4; for (uint64_t i = 0; i != NumNops; ++i) OW->Write32(0); return true; } /// processFixupValue - Target hook to process the literal value of a fixup /// if necessary. void MipsAsmBackend::processFixupValue(const MCAssembler &Asm, const MCAsmLayout &Layout, const MCFixup &Fixup, const MCFragment *DF, const MCValue &Target, uint64_t &Value, bool &IsResolved) { // At this point we'll ignore the value returned by adjustFixupValue as // we are only checking if the fixup can be applied correctly. We have // access to MCContext from here which allows us to report a fatal error // with *possibly* a source code location. (void)adjustFixupValue(Fixup, Value, &Asm.getContext()); } // MCAsmBackend MCAsmBackend *llvm::createMipsAsmBackendEL32(const Target &T, const MCRegisterInfo &MRI, StringRef TT, StringRef CPU) { return new MipsAsmBackend(T, Triple(TT).getOS(), /*IsLittle*/true, /*Is64Bit*/false); } MCAsmBackend *llvm::createMipsAsmBackendEB32(const Target &T, const MCRegisterInfo &MRI, StringRef TT, StringRef CPU) { return new MipsAsmBackend(T, Triple(TT).getOS(), /*IsLittle*/false, /*Is64Bit*/false); } MCAsmBackend *llvm::createMipsAsmBackendEL64(const Target &T, const MCRegisterInfo &MRI, StringRef TT, StringRef CPU) { return new MipsAsmBackend(T, Triple(TT).getOS(), /*IsLittle*/true, /*Is64Bit*/true); } MCAsmBackend *llvm::createMipsAsmBackendEB64(const Target &T, const MCRegisterInfo &MRI, StringRef TT, StringRef CPU) { return new MipsAsmBackend(T, Triple(TT).getOS(), /*IsLittle*/false, /*Is64Bit*/true); }