X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTarget%2FARM%2FMCTargetDesc%2FARMAsmBackend.cpp;h=1fe2dbe78665e65891975eaeb9ff58959c5e5041;hb=869394014ed102973f22648019d3c4c0979ca137;hp=9b4d2518b878ca2e401ae2a67820023c6a89c07d;hpb=d0d3f7e01ff7f83575816f6e1d75aa2224ebc2cb;p=oota-llvm.git diff --git a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp index 9b4d2518b87..1fe2dbe7866 100644 --- a/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp +++ b/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp @@ -8,166 +8,320 @@ //===----------------------------------------------------------------------===// #include "MCTargetDesc/ARMMCTargetDesc.h" +#include "MCTargetDesc/ARMAddressingModes.h" +#include "MCTargetDesc/ARMAsmBackend.h" +#include "MCTargetDesc/ARMAsmBackendDarwin.h" +#include "MCTargetDesc/ARMAsmBackendELF.h" +#include "MCTargetDesc/ARMAsmBackendWinCOFF.h" #include "MCTargetDesc/ARMBaseInfo.h" #include "MCTargetDesc/ARMFixupKinds.h" -#include "MCTargetDesc/ARMAddressingModes.h" -#include "llvm/ADT/Twine.h" +#include "llvm/ADT/StringSwitch.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/MCExpr.h" +#include "llvm/MC/MCFixupKindInfo.h" #include "llvm/MC/MCMachObjectWriter.h" #include "llvm/MC/MCObjectWriter.h" #include "llvm/MC/MCSectionELF.h" #include "llvm/MC/MCSectionMachO.h" -#include "llvm/MC/MCAsmBackend.h" #include "llvm/MC/MCSubtargetInfo.h" -#include "llvm/Object/MachOFormat.h" +#include "llvm/MC/MCValue.h" #include "llvm/Support/ELF.h" #include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/MachO.h" +#include "llvm/Support/TargetParser.h" #include "llvm/Support/raw_ostream.h" using namespace llvm; namespace { class ARMELFObjectWriter : public MCELFObjectTargetWriter { public: - ARMELFObjectWriter(Triple::OSType OSType) - : MCELFObjectTargetWriter(/*Is64Bit*/ false, OSType, ELF::EM_ARM, - /*HasRelocationAddend*/ false) {} + ARMELFObjectWriter(uint8_t OSABI) + : MCELFObjectTargetWriter(/*Is64Bit*/ false, OSABI, ELF::EM_ARM, + /*HasRelocationAddend*/ false) {} }; -class ARMAsmBackend : public MCAsmBackend { - const MCSubtargetInfo* STI; - bool isThumbMode; // Currently emitting Thumb code. -public: - ARMAsmBackend(const Target &T, const StringRef TT) - : MCAsmBackend(), STI(ARM_MC::createARMMCSubtargetInfo(TT, "", "")), - isThumbMode(false) {} +const MCFixupKindInfo &ARMAsmBackend::getFixupKindInfo(MCFixupKind Kind) const { + const static MCFixupKindInfo InfosLE[ARM::NumTargetFixupKinds] = { + // This table *must* be in the order that the fixup_* kinds are defined in + // ARMFixupKinds.h. + // + // Name Offset (bits) Size (bits) Flags + {"fixup_arm_ldst_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_ldst_pcrel_12", 0, 32, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_pcrel_10_unscaled", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_pcrel_10", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_pcrel_10", 0, 32, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_thumb_adr_pcrel_10", 0, 8, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_adr_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_adr_pcrel_12", 0, 32, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_condbranch", 0, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_uncondbranch", 0, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_condbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_uncondbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_br", 0, 16, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_uncondbl", 0, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_condbl", 0, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_blx", 0, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_bl", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_blx", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_cb", 0, 16, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_cp", 0, 8, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_thumb_bcc", 0, 8, MCFixupKindInfo::FKF_IsPCRel}, + // movw / movt: 16-bits immediate but scattered into two chunks 0 - 12, 16 + // - 19. + {"fixup_arm_movt_hi16", 0, 20, 0}, + {"fixup_arm_movw_lo16", 0, 20, 0}, + {"fixup_t2_movt_hi16", 0, 20, 0}, + {"fixup_t2_movw_lo16", 0, 20, 0}, + }; + const static MCFixupKindInfo InfosBE[ARM::NumTargetFixupKinds] = { + // This table *must* be in the order that the fixup_* kinds are defined in + // ARMFixupKinds.h. + // + // Name Offset (bits) Size (bits) Flags + {"fixup_arm_ldst_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_ldst_pcrel_12", 0, 32, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_pcrel_10_unscaled", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_pcrel_10", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_pcrel_10", 0, 32, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_thumb_adr_pcrel_10", 8, 8, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_adr_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_adr_pcrel_12", 0, 32, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_condbranch", 8, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_uncondbranch", 8, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_condbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_t2_uncondbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_br", 0, 16, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_uncondbl", 8, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_condbl", 8, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_blx", 8, 24, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_bl", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_blx", 0, 32, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_cb", 0, 16, MCFixupKindInfo::FKF_IsPCRel}, + {"fixup_arm_thumb_cp", 8, 8, + MCFixupKindInfo::FKF_IsPCRel | + MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, + {"fixup_arm_thumb_bcc", 8, 8, MCFixupKindInfo::FKF_IsPCRel}, + // movw / movt: 16-bits immediate but scattered into two chunks 0 - 12, 16 + // - 19. + {"fixup_arm_movt_hi16", 12, 20, 0}, + {"fixup_arm_movw_lo16", 12, 20, 0}, + {"fixup_t2_movt_hi16", 12, 20, 0}, + {"fixup_t2_movw_lo16", 12, 20, 0}, + }; + + if (Kind < FirstTargetFixupKind) + return MCAsmBackend::getFixupKindInfo(Kind); + + assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && + "Invalid kind!"); + return (IsLittleEndian ? InfosLE : InfosBE)[Kind - FirstTargetFixupKind]; +} - ~ARMAsmBackend() { - delete STI; +void ARMAsmBackend::handleAssemblerFlag(MCAssemblerFlag Flag) { + switch (Flag) { + default: + break; + case MCAF_Code16: + setIsThumb(true); + break; + case MCAF_Code32: + setIsThumb(false); + break; } +} +} // end anonymous namespace - unsigned getNumFixupKinds() const { return ARM::NumTargetFixupKinds; } +unsigned ARMAsmBackend::getRelaxedOpcode(unsigned Op) const { + bool HasThumb2 = STI->getFeatureBits()[ARM::FeatureThumb2]; - bool hasNOP() const { - return (STI->getFeatureBits() & ARM::HasV6T2Ops) != 0; + switch (Op) { + default: + return Op; + case ARM::tBcc: + return HasThumb2 ? (unsigned)ARM::t2Bcc : Op; + case ARM::tLDRpci: + return HasThumb2 ? (unsigned)ARM::t2LDRpci : Op; + case ARM::tADR: + return HasThumb2 ? (unsigned)ARM::t2ADR : Op; + case ARM::tB: + return HasThumb2 ? (unsigned)ARM::t2B : Op; + case ARM::tCBZ: + return ARM::tHINT; + case ARM::tCBNZ: + return ARM::tHINT; } +} - const MCFixupKindInfo &getFixupKindInfo(MCFixupKind Kind) const { - const static MCFixupKindInfo Infos[ARM::NumTargetFixupKinds] = { -// This table *must* be in the order that the fixup_* kinds are defined in -// ARMFixupKinds.h. -// -// Name Offset (bits) Size (bits) Flags -{ "fixup_arm_ldst_pcrel_12", 1, 24, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_ldst_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel | - MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, -{ "fixup_arm_pcrel_10", 1, 24, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_pcrel_10", 0, 32, MCFixupKindInfo::FKF_IsPCRel | - MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, -{ "fixup_thumb_adr_pcrel_10",0, 8, MCFixupKindInfo::FKF_IsPCRel | - MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, -{ "fixup_arm_adr_pcrel_12", 1, 24, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_adr_pcrel_12", 0, 32, MCFixupKindInfo::FKF_IsPCRel | - MCFixupKindInfo::FKF_IsAlignedDownTo32Bits}, -{ "fixup_arm_condbranch", 0, 24, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_uncondbranch", 0, 24, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_condbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_uncondbranch", 0, 32, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_thumb_br", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_thumb_bl", 0, 32, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_thumb_blx", 7, 21, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_thumb_cb", 0, 16, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_thumb_cp", 1, 8, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_thumb_bcc", 0, 8, MCFixupKindInfo::FKF_IsPCRel }, -// movw / movt: 16-bits immediate but scattered into two chunks 0 - 12, 16 - 19. -{ "fixup_arm_movt_hi16", 0, 20, 0 }, -{ "fixup_arm_movw_lo16", 0, 20, 0 }, -{ "fixup_t2_movt_hi16", 0, 20, 0 }, -{ "fixup_t2_movw_lo16", 0, 20, 0 }, -{ "fixup_arm_movt_hi16_pcrel", 0, 20, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_arm_movw_lo16_pcrel", 0, 20, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_movt_hi16_pcrel", 0, 20, MCFixupKindInfo::FKF_IsPCRel }, -{ "fixup_t2_movw_lo16_pcrel", 0, 20, MCFixupKindInfo::FKF_IsPCRel }, - }; - - if (Kind < FirstTargetFixupKind) - return MCAsmBackend::getFixupKindInfo(Kind); - - assert(unsigned(Kind - FirstTargetFixupKind) < getNumFixupKinds() && - "Invalid kind!"); - return Infos[Kind - FirstTargetFixupKind]; - } - - bool MayNeedRelaxation(const MCInst &Inst) const; - - void RelaxInstruction(const MCInst &Inst, MCInst &Res) const; - - bool WriteNopData(uint64_t Count, MCObjectWriter *OW) const; - - void HandleAssemblerFlag(MCAssemblerFlag Flag) { - switch (Flag) { - default: break; - case MCAF_Code16: - setIsThumb(true); - break; - case MCAF_Code32: - setIsThumb(false); - break; - } +bool ARMAsmBackend::mayNeedRelaxation(const MCInst &Inst) const { + if (getRelaxedOpcode(Inst.getOpcode()) != Inst.getOpcode()) + return true; + return false; +} + +bool ARMAsmBackend::fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value, + const MCRelaxableFragment *DF, + const MCAsmLayout &Layout) const { + switch ((unsigned)Fixup.getKind()) { + case ARM::fixup_arm_thumb_br: { + // Relaxing tB to t2B. tB has a signed 12-bit displacement with the + // low bit being an implied zero. There's an implied +4 offset for the + // branch, so we adjust the other way here to determine what's + // encodable. + // + // Relax if the value is too big for a (signed) i8. + int64_t Offset = int64_t(Value) - 4; + return Offset > 2046 || Offset < -2048; } + case ARM::fixup_arm_thumb_bcc: { + // Relaxing tBcc to t2Bcc. tBcc has a signed 9-bit displacement with the + // low bit being an implied zero. There's an implied +4 offset for the + // branch, so we adjust the other way here to determine what's + // encodable. + // + // Relax if the value is too big for a (signed) i8. + int64_t Offset = int64_t(Value) - 4; + return Offset > 254 || Offset < -256; + } + case ARM::fixup_thumb_adr_pcrel_10: + case ARM::fixup_arm_thumb_cp: { + // If the immediate is negative, greater than 1020, or not a multiple + // of four, the wide version of the instruction must be used. + int64_t Offset = int64_t(Value) - 4; + return Offset > 1020 || Offset < 0 || Offset & 3; + } + case ARM::fixup_arm_thumb_cb: + // If we have a Thumb CBZ or CBNZ instruction and its target is the next + // instruction it is is actually out of range for the instruction. + // It will be changed to a NOP. + int64_t Offset = (Value & ~1); + return Offset == 2; + } + llvm_unreachable("Unexpected fixup kind in fixupNeedsRelaxation()!"); +} - unsigned getPointerSize() const { return 4; } - bool isThumb() const { return isThumbMode; } - void setIsThumb(bool it) { isThumbMode = it; } -}; -} // end anonymous namespace +void ARMAsmBackend::relaxInstruction(const MCInst &Inst, MCInst &Res) const { + unsigned RelaxedOp = getRelaxedOpcode(Inst.getOpcode()); -bool ARMAsmBackend::MayNeedRelaxation(const MCInst &Inst) const { - // FIXME: Thumb targets, different move constant targets.. - return false; -} + // Sanity check w/ diagnostic if we get here w/ a bogus instruction. + if (RelaxedOp == Inst.getOpcode()) { + SmallString<256> Tmp; + raw_svector_ostream OS(Tmp); + Inst.dump_pretty(OS); + OS << "\n"; + report_fatal_error("unexpected instruction to relax: " + OS.str()); + } + + // If we are changing Thumb CBZ or CBNZ instruction to a NOP, aka tHINT, we + // have to change the operands too. + if ((Inst.getOpcode() == ARM::tCBZ || Inst.getOpcode() == ARM::tCBNZ) && + RelaxedOp == ARM::tHINT) { + Res.setOpcode(RelaxedOp); + Res.addOperand(MCOperand::createImm(0)); + Res.addOperand(MCOperand::createImm(14)); + Res.addOperand(MCOperand::createReg(0)); + return; + } -void ARMAsmBackend::RelaxInstruction(const MCInst &Inst, MCInst &Res) const { - assert(0 && "ARMAsmBackend::RelaxInstruction() unimplemented"); - return; + // The rest of instructions we're relaxing have the same operands. + // We just need to update to the proper opcode. + Res = Inst; + Res.setOpcode(RelaxedOp); } -bool ARMAsmBackend::WriteNopData(uint64_t Count, MCObjectWriter *OW) const { +bool ARMAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const { const uint16_t Thumb1_16bitNopEncoding = 0x46c0; // using MOV r8,r8 const uint16_t Thumb2_16bitNopEncoding = 0xbf00; // NOP - const uint32_t ARMv4_NopEncoding = 0xe1a0000; // using MOV r0,r0 - const uint32_t ARMv6T2_NopEncoding = 0xe3207800; // NOP + const uint32_t ARMv4_NopEncoding = 0xe1a00000; // using MOV r0,r0 + const uint32_t ARMv6T2_NopEncoding = 0xe320f000; // NOP if (isThumb()) { - const uint16_t nopEncoding = hasNOP() ? Thumb2_16bitNopEncoding - : Thumb1_16bitNopEncoding; + const uint16_t nopEncoding = + hasNOP() ? Thumb2_16bitNopEncoding : Thumb1_16bitNopEncoding; uint64_t NumNops = Count / 2; for (uint64_t i = 0; i != NumNops; ++i) - OW->Write16(nopEncoding); + OW->write16(nopEncoding); if (Count & 1) - OW->Write8(0); + OW->write8(0); return true; } // ARM mode - const uint32_t nopEncoding = hasNOP() ? ARMv6T2_NopEncoding - : ARMv4_NopEncoding; + const uint32_t nopEncoding = + hasNOP() ? ARMv6T2_NopEncoding : ARMv4_NopEncoding; uint64_t NumNops = Count / 4; for (uint64_t i = 0; i != NumNops; ++i) - OW->Write32(nopEncoding); + OW->write32(nopEncoding); // FIXME: should this function return false when unable to write exactly // 'Count' bytes with NOP encodings? switch (Count % 4) { - default: break; // No leftover bytes to write - case 1: OW->Write8(0); break; - case 2: OW->Write16(0); break; - case 3: OW->Write16(0); OW->Write8(0xa0); break; + default: + break; // No leftover bytes to write + case 1: + OW->write8(0); + break; + case 2: + OW->write16(0); + break; + case 3: + OW->write16(0); + OW->write8(0xa0); + break; } return true; } -static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { +static uint32_t swapHalfWords(uint32_t Value, bool IsLittleEndian) { + if (IsLittleEndian) { + // Note that the halfwords are stored high first and low second in thumb; + // so we need to swap the fixup value here to map properly. + uint32_t Swapped = (Value & 0xFFFF0000) >> 16; + Swapped |= (Value & 0x0000FFFF) << 16; + return Swapped; + } else + return Value; +} + +static uint32_t joinHalfWords(uint32_t FirstHalf, uint32_t SecondHalf, + bool IsLittleEndian) { + uint32_t Value; + + if (IsLittleEndian) { + Value = (SecondHalf & 0xFFFF) << 16; + Value |= (FirstHalf & 0xFFFF); + } else { + Value = (SecondHalf & 0xFFFF); + Value |= (FirstHalf & 0xFFFF) << 16; + } + + return Value; +} + +static unsigned adjustFixupValue(const MCFixup &Fixup, uint64_t Value, + bool IsPCRel, MCContext *Ctx, + bool IsLittleEndian) { + unsigned Kind = Fixup.getKind(); switch (Kind) { default: llvm_unreachable("Unknown fixup kind!"); @@ -175,28 +329,27 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { case FK_Data_2: case FK_Data_4: return Value; + case FK_SecRel_2: + return Value; + case FK_SecRel_4: + return Value; case ARM::fixup_arm_movt_hi16: - Value >>= 16; - // Fallthrough - case ARM::fixup_arm_movw_lo16: - case ARM::fixup_arm_movt_hi16_pcrel: - case ARM::fixup_arm_movw_lo16_pcrel: { + if (!IsPCRel) + Value >>= 16; + // Fallthrough + case ARM::fixup_arm_movw_lo16: { unsigned Hi4 = (Value & 0xF000) >> 12; unsigned Lo12 = Value & 0x0FFF; - assert ((((int64_t)Value) >= -0x8000) && (((int64_t)Value) <= 0x7fff) && - "Out of range pc-relative fixup value!"); // inst{19-16} = Hi4; // inst{11-0} = Lo12; Value = (Hi4 << 16) | (Lo12); return Value; } case ARM::fixup_t2_movt_hi16: - Value >>= 16; - // Fallthrough - case ARM::fixup_t2_movw_lo16: - case ARM::fixup_t2_movt_hi16_pcrel: //FIXME: Shouldn't this be shifted like - // the other hi16 fixup? - case ARM::fixup_t2_movw_lo16_pcrel: { + if (!IsPCRel) + Value >>= 16; + // Fallthrough + case ARM::fixup_t2_movw_lo16: { unsigned Hi4 = (Value & 0xF000) >> 12; unsigned i = (Value & 0x800) >> 11; unsigned Mid3 = (Value & 0x700) >> 8; @@ -205,19 +358,13 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { // inst{26} = i; // inst{14-12} = Mid3; // inst{7-0} = Lo8; - // The value comes in as the whole thing, not just the portion required - // for this fixup, so we need to mask off the bits not handled by this - // portion (lo vs. hi). - Value &= 0xffff; Value = (Hi4 << 16) | (i << 26) | (Mid3 << 12) | (Lo8); - uint64_t swapped = (Value & 0xFFFF0000) >> 16; - swapped |= (Value & 0x0000FFFF) << 16; - return swapped; + return swapHalfWords(Value, IsLittleEndian); } case ARM::fixup_arm_ldst_pcrel_12: // ARM PC-relative values are offset by 8. Value -= 4; - // FALLTHROUGH + // FALLTHROUGH case ARM::fixup_t2_ldst_pcrel_12: { // Offset by 4, adjusted by two due to the half-word ordering of thumb. Value -= 4; @@ -226,16 +373,14 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { Value = -Value; isAdd = false; } - assert ((Value < 4096) && "Out of range pc-relative fixup value!"); + if (Ctx && Value >= 4096) + Ctx->reportFatalError(Fixup.getLoc(), "out of range pc-relative fixup value"); Value |= isAdd << 23; // Same addressing mode as fixup_arm_pcrel_10, // but with 16-bit halfwords swapped. - if (Kind == ARM::fixup_t2_ldst_pcrel_12) { - uint64_t swapped = (Value & 0xFFFF0000) >> 16; - swapped |= (Value & 0x0000FFFF) << 16; - return swapped; - } + if (Kind == ARM::fixup_t2_ldst_pcrel_12) + return swapHalfWords(Value, IsLittleEndian); return Value; } @@ -249,8 +394,8 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { Value = -Value; opc = 2; // 0b0010 } - assert(ARM_AM::getSOImmVal(Value) != -1 && - "Out of range pc-relative fixup value!"); + if (Ctx && ARM_AM::getSOImmVal(Value) == -1) + Ctx->reportFatalError(Fixup.getLoc(), "out of range pc-relative fixup value"); // Encode the immediate and shift the opcode into place. return ARM_AM::getSOImmVal(Value) | (opc << 21); } @@ -268,36 +413,39 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { out |= (Value & 0x700) << 4; out |= (Value & 0x0FF); - uint64_t swapped = (out & 0xFFFF0000) >> 16; - swapped |= (out & 0x0000FFFF) << 16; - return swapped; + return swapHalfWords(out, IsLittleEndian); } case ARM::fixup_arm_condbranch: case ARM::fixup_arm_uncondbranch: + case ARM::fixup_arm_uncondbl: + case ARM::fixup_arm_condbl: + case ARM::fixup_arm_blx: // These values don't encode the low two bits since they're always zero. // Offset by 8 just as above. + if (const MCSymbolRefExpr *SRE = + dyn_cast(Fixup.getValue())) + if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_TLSCALL) + return 0; return 0xffffff & ((Value - 8) >> 2); case ARM::fixup_t2_uncondbranch: { Value = Value - 4; Value >>= 1; // Low bit is not encoded. uint32_t out = 0; - bool I = Value & 0x800000; + bool I = Value & 0x800000; bool J1 = Value & 0x400000; bool J2 = Value & 0x200000; J1 ^= I; J2 ^= I; - out |= I << 26; // S bit - out |= !J1 << 13; // J1 bit - out |= !J2 << 11; // J2 bit - out |= (Value & 0x1FF800) << 5; // imm6 field - out |= (Value & 0x0007FF); // imm11 field + out |= I << 26; // S bit + out |= !J1 << 13; // J1 bit + out |= !J2 << 11; // J2 bit + out |= (Value & 0x1FF800) << 5; // imm6 field + out |= (Value & 0x0007FF); // imm11 field - uint64_t swapped = (out & 0xFFFF0000) >> 16; - swapped |= (out & 0x0000FFFF) << 16; - return swapped; + return swapHalfWords(out, IsLittleEndian); } case ARM::fixup_t2_condbranch: { Value = Value - 4; @@ -310,44 +458,65 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { out |= (Value & 0x1F800) << 5; // imm6 field out |= (Value & 0x007FF); // imm11 field - uint32_t swapped = (out & 0xFFFF0000) >> 16; - swapped |= (out & 0x0000FFFF) << 16; - return swapped; + return swapHalfWords(out, IsLittleEndian); } case ARM::fixup_arm_thumb_bl: { // The value doesn't encode the low bit (always zero) and is offset by - // four. The value is encoded into disjoint bit positions in the destination - // opcode. x = unchanged, I = immediate value bit, S = sign extension bit + // four. The 32-bit immediate value is encoded as + // imm32 = SignExtend(S:I1:I2:imm10:imm11:0) + // where I1 = NOT(J1 ^ S) and I2 = NOT(J2 ^ S). + // The value is encoded into disjoint bit positions in the destination + // opcode. x = unchanged, I = immediate value bit, S = sign extension bit, + // J = either J1 or J2 bit // - // BL: xxxxxSIIIIIIIIII xxxxxIIIIIIIIIII + // BL: xxxxxSIIIIIIIIII xxJxJIIIIIIIIIII // // Note that the halfwords are stored high first, low second; so we need // to transpose the fixup value here to map properly. - unsigned isNeg = (int64_t(Value - 4) < 0) ? 1 : 0; - uint32_t Binary = 0; - Value = 0x3fffff & ((Value - 4) >> 1); - Binary = (Value & 0x7ff) << 16; // Low imm11 value. - Binary |= (Value & 0x1ffc00) >> 11; // High imm10 value. - Binary |= isNeg << 10; // Sign bit. - return Binary; + uint32_t offset = (Value - 4) >> 1; + uint32_t signBit = (offset & 0x800000) >> 23; + uint32_t I1Bit = (offset & 0x400000) >> 22; + uint32_t J1Bit = (I1Bit ^ 0x1) ^ signBit; + uint32_t I2Bit = (offset & 0x200000) >> 21; + uint32_t J2Bit = (I2Bit ^ 0x1) ^ signBit; + uint32_t imm10Bits = (offset & 0x1FF800) >> 11; + uint32_t imm11Bits = (offset & 0x000007FF); + + uint32_t FirstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10Bits); + uint32_t SecondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) | + (uint16_t)imm11Bits); + return joinHalfWords(FirstHalf, SecondHalf, IsLittleEndian); } case ARM::fixup_arm_thumb_blx: { // The value doesn't encode the low two bits (always zero) and is offset by - // four (see fixup_arm_thumb_cp). The value is encoded into disjoint bit - // positions in the destination opcode. x = unchanged, I = immediate value - // bit, S = sign extension bit, 0 = zero. + // four (see fixup_arm_thumb_cp). The 32-bit immediate value is encoded as + // imm32 = SignExtend(S:I1:I2:imm10H:imm10L:00) + // where I1 = NOT(J1 ^ S) and I2 = NOT(J2 ^ S). + // The value is encoded into disjoint bit positions in the destination + // opcode. x = unchanged, I = immediate value bit, S = sign extension bit, + // J = either J1 or J2 bit, 0 = zero. // - // BLX: xxxxxSIIIIIIIIII xxxxxIIIIIIIIII0 + // BLX: xxxxxSIIIIIIIIII xxJxJIIIIIIIIII0 // // Note that the halfwords are stored high first, low second; so we need // to transpose the fixup value here to map properly. - unsigned isNeg = (int64_t(Value-4) < 0) ? 1 : 0; - uint32_t Binary = 0; - Value = 0xfffff & ((Value - 2) >> 2); - Binary = (Value & 0x3ff) << 17; // Low imm10L value. - Binary |= (Value & 0xffc00) >> 10; // High imm10H value. - Binary |= isNeg << 10; // Sign bit. - return Binary; + uint32_t offset = (Value - 2) >> 2; + if (const MCSymbolRefExpr *SRE = + dyn_cast(Fixup.getValue())) + if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_TLSCALL) + offset = 0; + uint32_t signBit = (offset & 0x400000) >> 22; + uint32_t I1Bit = (offset & 0x200000) >> 21; + uint32_t J1Bit = (I1Bit ^ 0x1) ^ signBit; + uint32_t I2Bit = (offset & 0x100000) >> 20; + uint32_t J2Bit = (I2Bit ^ 0x1) ^ signBit; + uint32_t imm10HBits = (offset & 0xFFC00) >> 10; + uint32_t imm10LBits = (offset & 0x3FF); + + uint32_t FirstHalf = (((uint16_t)signBit << 10) | (uint16_t)imm10HBits); + uint32_t SecondHalf = (((uint16_t)J1Bit << 13) | ((uint16_t)J2Bit << 11) | + ((uint16_t)imm10LBits) << 1); + return joinHalfWords(FirstHalf, SecondHalf, IsLittleEndian); } case ARM::fixup_arm_thumb_cp: // Offset by 4, and don't encode the low two bits. Two bytes of that @@ -365,10 +534,24 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { case ARM::fixup_arm_thumb_bcc: // Offset by 4 and don't encode the lower bit, which is always 0. return ((Value - 4) >> 1) & 0xff; + case ARM::fixup_arm_pcrel_10_unscaled: { + Value = Value - 8; // ARM fixups offset by an additional word and don't + // need to adjust for the half-word ordering. + bool isAdd = true; + if ((int64_t)Value < 0) { + Value = -Value; + isAdd = false; + } + // The value has the low 4 bits encoded in [3:0] and the high 4 in [11:8]. + if (Ctx && Value >= 256) + Ctx->reportFatalError(Fixup.getLoc(), "out of range pc-relative fixup value"); + Value = (Value & 0xf) | ((Value & 0xf0) << 4); + return Value | (isAdd << 23); + } case ARM::fixup_arm_pcrel_10: Value = Value - 4; // ARM fixups offset by an additional word and don't // need to adjust for the half-word ordering. - // Fall through. + // Fall through. case ARM::fixup_t2_pcrel_10: { // Offset by 4, adjusted by two due to the half-word ordering of thumb. Value = Value - 4; @@ -379,79 +562,63 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) { } // These values don't encode the low two bits since they're always zero. Value >>= 2; - assert ((Value < 256) && "Out of range pc-relative fixup value!"); + if (Ctx && Value >= 256) + Ctx->reportFatalError(Fixup.getLoc(), "out of range pc-relative fixup value"); Value |= isAdd << 23; - // Same addressing mode as fixup_arm_pcrel_10, - // but with 16-bit halfwords swapped. - if (Kind == ARM::fixup_t2_pcrel_10) { - uint32_t swapped = (Value & 0xFFFF0000) >> 16; - swapped |= (Value & 0x0000FFFF) << 16; - return swapped; - } + // Same addressing mode as fixup_arm_pcrel_10, but with 16-bit halfwords + // swapped. + if (Kind == ARM::fixup_t2_pcrel_10) + return swapHalfWords(Value, IsLittleEndian); return Value; } } } -namespace { - -// FIXME: This should be in a separate file. -// ELF is an ELF of course... -class ELFARMAsmBackend : public ARMAsmBackend { -public: - Triple::OSType OSType; - ELFARMAsmBackend(const Target &T, const StringRef TT, - Triple::OSType _OSType) - : ARMAsmBackend(T, TT), OSType(_OSType) { } - - void ApplyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, - uint64_t Value) const; - - MCObjectWriter *createObjectWriter(raw_ostream &OS) const { - return createELFObjectWriter(new ARMELFObjectWriter(OSType), OS, - /*IsLittleEndian*/ true); - } -}; - -// FIXME: Raise this to share code between Darwin and ELF. -void ELFARMAsmBackend::ApplyFixup(const MCFixup &Fixup, char *Data, - unsigned DataSize, uint64_t Value) const { - unsigned NumBytes = 4; // FIXME: 2 for Thumb - Value = adjustFixupValue(Fixup.getKind(), Value); - if (!Value) return; // Doesn't change encoding. - - unsigned Offset = Fixup.getOffset(); - - // For each byte of the fragment that the fixup touches, mask in the bits from - // the fixup value. The Value has been "split up" into the appropriate - // bitfields above. - for (unsigned i = 0; i != NumBytes; ++i) - Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff); -} - -// FIXME: This should be in a separate file. -class DarwinARMAsmBackend : public ARMAsmBackend { -public: - const object::mach::CPUSubtypeARM Subtype; - DarwinARMAsmBackend(const Target &T, const StringRef TT, - object::mach::CPUSubtypeARM st) - : ARMAsmBackend(T, TT), Subtype(st) { } - - MCObjectWriter *createObjectWriter(raw_ostream &OS) const { - return createARMMachObjectWriter(OS, /*Is64Bit=*/false, - object::mach::CTM_ARM, - Subtype); +void ARMAsmBackend::processFixupValue(const MCAssembler &Asm, + const MCAsmLayout &Layout, + const MCFixup &Fixup, + const MCFragment *DF, + const MCValue &Target, uint64_t &Value, + bool &IsResolved) { + const MCSymbolRefExpr *A = Target.getSymA(); + // Some fixups to thumb function symbols need the low bit (thumb bit) + // twiddled. + if ((unsigned)Fixup.getKind() != ARM::fixup_arm_ldst_pcrel_12 && + (unsigned)Fixup.getKind() != ARM::fixup_t2_ldst_pcrel_12 && + (unsigned)Fixup.getKind() != ARM::fixup_arm_adr_pcrel_12 && + (unsigned)Fixup.getKind() != ARM::fixup_thumb_adr_pcrel_10 && + (unsigned)Fixup.getKind() != ARM::fixup_t2_adr_pcrel_12 && + (unsigned)Fixup.getKind() != ARM::fixup_arm_thumb_cp) { + if (A) { + const MCSymbol &Sym = A->getSymbol(); + if (Asm.isThumbFunc(&Sym)) + Value |= 1; + } } - - void ApplyFixup(const MCFixup &Fixup, char *Data, unsigned DataSize, - uint64_t Value) const; - - virtual bool doesSectionRequireSymbols(const MCSection &Section) const { - return false; + // For Thumb1 BL instruction, it is possible to be a long jump between + // the basic blocks of the same function. Thus, we would like to resolve + // the offset when the destination has the same MCFragment. + if (A && (unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_bl) { + const MCSymbol &Sym = A->getSymbol(); + IsResolved = (Sym.getFragment() == DF); } -}; + // We must always generate a relocation for BL/BLX instructions if we have + // a symbol to reference, as the linker relies on knowing the destination + // symbol's thumb-ness to get interworking right. + if (A && ((unsigned)Fixup.getKind() == ARM::fixup_arm_thumb_blx || + (unsigned)Fixup.getKind() == ARM::fixup_arm_blx || + (unsigned)Fixup.getKind() == ARM::fixup_arm_uncondbl || + (unsigned)Fixup.getKind() == ARM::fixup_arm_condbl)) + IsResolved = false; + + // Try to get the encoded value for the fixup as-if we're mapping it into + // the instruction. This allows adjustFixupValue() to issue a diagnostic + // if the value aren't invalid. + (void)adjustFixupValue(Fixup, Value, false, &Asm.getContext(), + IsLittleEndian); +} /// getFixupKindNumBytes - The number of bytes the fixup may change. static unsigned getFixupKindNumBytes(unsigned Kind) { @@ -470,9 +637,13 @@ static unsigned getFixupKindNumBytes(unsigned Kind) { case ARM::fixup_arm_thumb_cb: return 2; + case ARM::fixup_arm_pcrel_10_unscaled: case ARM::fixup_arm_ldst_pcrel_12: case ARM::fixup_arm_pcrel_10: case ARM::fixup_arm_adr_pcrel_12: + case ARM::fixup_arm_uncondbl: + case ARM::fixup_arm_condbl: + case ARM::fixup_arm_blx: case ARM::fixup_arm_condbranch: case ARM::fixup_arm_uncondbranch: return 3; @@ -487,51 +658,166 @@ static unsigned getFixupKindNumBytes(unsigned Kind) { case ARM::fixup_arm_thumb_blx: case ARM::fixup_arm_movt_hi16: case ARM::fixup_arm_movw_lo16: - case ARM::fixup_arm_movt_hi16_pcrel: - case ARM::fixup_arm_movw_lo16_pcrel: case ARM::fixup_t2_movt_hi16: case ARM::fixup_t2_movw_lo16: - case ARM::fixup_t2_movt_hi16_pcrel: - case ARM::fixup_t2_movw_lo16_pcrel: + return 4; + + case FK_SecRel_2: + return 2; + case FK_SecRel_4: return 4; } } -void DarwinARMAsmBackend::ApplyFixup(const MCFixup &Fixup, char *Data, - unsigned DataSize, uint64_t Value) const { +/// getFixupKindContainerSizeBytes - The number of bytes of the +/// container involved in big endian. +static unsigned getFixupKindContainerSizeBytes(unsigned Kind) { + switch (Kind) { + default: + llvm_unreachable("Unknown fixup kind!"); + + case FK_Data_1: + return 1; + case FK_Data_2: + return 2; + case FK_Data_4: + return 4; + + case ARM::fixup_arm_thumb_bcc: + case ARM::fixup_arm_thumb_cp: + case ARM::fixup_thumb_adr_pcrel_10: + case ARM::fixup_arm_thumb_br: + case ARM::fixup_arm_thumb_cb: + // Instruction size is 2 bytes. + return 2; + + case ARM::fixup_arm_pcrel_10_unscaled: + case ARM::fixup_arm_ldst_pcrel_12: + case ARM::fixup_arm_pcrel_10: + case ARM::fixup_arm_adr_pcrel_12: + case ARM::fixup_arm_uncondbl: + case ARM::fixup_arm_condbl: + case ARM::fixup_arm_blx: + case ARM::fixup_arm_condbranch: + case ARM::fixup_arm_uncondbranch: + case ARM::fixup_t2_ldst_pcrel_12: + case ARM::fixup_t2_condbranch: + case ARM::fixup_t2_uncondbranch: + case ARM::fixup_t2_pcrel_10: + case ARM::fixup_t2_adr_pcrel_12: + case ARM::fixup_arm_thumb_bl: + case ARM::fixup_arm_thumb_blx: + case ARM::fixup_arm_movt_hi16: + case ARM::fixup_arm_movw_lo16: + case ARM::fixup_t2_movt_hi16: + case ARM::fixup_t2_movw_lo16: + // Instruction size is 4 bytes. + return 4; + } +} + +void ARMAsmBackend::applyFixup(const MCFixup &Fixup, char *Data, + unsigned DataSize, uint64_t Value, + bool IsPCRel) const { unsigned NumBytes = getFixupKindNumBytes(Fixup.getKind()); - Value = adjustFixupValue(Fixup.getKind(), Value); - if (!Value) return; // Doesn't change encoding. + Value = adjustFixupValue(Fixup, Value, IsPCRel, nullptr, IsLittleEndian); + if (!Value) + return; // Doesn't change encoding. unsigned Offset = Fixup.getOffset(); assert(Offset + NumBytes <= DataSize && "Invalid fixup offset!"); - // For each byte of the fragment that the fixup touches, mask in the - // bits from the fixup value. - for (unsigned i = 0; i != NumBytes; ++i) - Data[Offset + i] |= uint8_t((Value >> (i * 8)) & 0xff); -} + // Used to point to big endian bytes. + unsigned FullSizeBytes; + if (!IsLittleEndian) { + FullSizeBytes = getFixupKindContainerSizeBytes(Fixup.getKind()); + assert((Offset + FullSizeBytes) <= DataSize && "Invalid fixup size!"); + assert(NumBytes <= FullSizeBytes && "Invalid fixup size!"); + } -} // end anonymous namespace + // For each byte of the fragment that the fixup touches, mask in the bits from + // the fixup value. The Value has been "split up" into the appropriate + // bitfields above. + for (unsigned i = 0; i != NumBytes; ++i) { + unsigned Idx = IsLittleEndian ? i : (FullSizeBytes - 1 - i); + Data[Offset + Idx] |= uint8_t((Value >> (i * 8)) & 0xff); + } +} -MCAsmBackend *llvm::createARMAsmBackend(const Target &T, StringRef TT) { - Triple TheTriple(TT); +static MachO::CPUSubTypeARM getMachOSubTypeFromArch(StringRef Arch) { + unsigned AK = ARM::parseArch(Arch); + switch (AK) { + default: + return MachO::CPU_SUBTYPE_ARM_V7; + case ARM::AK_ARMV4T: + return MachO::CPU_SUBTYPE_ARM_V4T; + case ARM::AK_ARMV6: + case ARM::AK_ARMV6K: + return MachO::CPU_SUBTYPE_ARM_V6; + case ARM::AK_ARMV5: + return MachO::CPU_SUBTYPE_ARM_V5; + case ARM::AK_ARMV5T: + case ARM::AK_ARMV5E: + case ARM::AK_ARMV5TE: + case ARM::AK_ARMV5TEJ: + return MachO::CPU_SUBTYPE_ARM_V5TEJ; + case ARM::AK_ARMV7: + return MachO::CPU_SUBTYPE_ARM_V7; + case ARM::AK_ARMV7S: + return MachO::CPU_SUBTYPE_ARM_V7S; + case ARM::AK_ARMV7K: + return MachO::CPU_SUBTYPE_ARM_V7K; + case ARM::AK_ARMV6M: + case ARM::AK_ARMV6SM: + return MachO::CPU_SUBTYPE_ARM_V6M; + case ARM::AK_ARMV7M: + return MachO::CPU_SUBTYPE_ARM_V7M; + case ARM::AK_ARMV7EM: + return MachO::CPU_SUBTYPE_ARM_V7EM; + } +} - if (TheTriple.isOSDarwin()) { - if (TheTriple.getArchName() == "armv4t" || - TheTriple.getArchName() == "thumbv4t") - return new DarwinARMAsmBackend(T, TT, object::mach::CSARM_V4T); - else if (TheTriple.getArchName() == "armv5e" || - TheTriple.getArchName() == "thumbv5e") - return new DarwinARMAsmBackend(T, TT, object::mach::CSARM_V5TEJ); - else if (TheTriple.getArchName() == "armv6" || - TheTriple.getArchName() == "thumbv6") - return new DarwinARMAsmBackend(T, TT, object::mach::CSARM_V6); - return new DarwinARMAsmBackend(T, TT, object::mach::CSARM_V7); +MCAsmBackend *llvm::createARMAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TheTriple, StringRef CPU, + bool isLittle) { + switch (TheTriple.getObjectFormat()) { + default: + llvm_unreachable("unsupported object format"); + case Triple::MachO: { + MachO::CPUSubTypeARM CS = getMachOSubTypeFromArch(TheTriple.getArchName()); + return new ARMAsmBackendDarwin(T, TheTriple, CS); + } + case Triple::COFF: + assert(TheTriple.isOSWindows() && "non-Windows ARM COFF is not supported"); + return new ARMAsmBackendWinCOFF(T, TheTriple); + case Triple::ELF: + assert(TheTriple.isOSBinFormatELF() && "using ELF for non-ELF target"); + uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TheTriple.getOS()); + return new ARMAsmBackendELF(T, TheTriple, OSABI, isLittle); } +} + +MCAsmBackend *llvm::createARMLEAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TT, StringRef CPU) { + return createARMAsmBackend(T, MRI, TT, CPU, true); +} + +MCAsmBackend *llvm::createARMBEAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TT, StringRef CPU) { + return createARMAsmBackend(T, MRI, TT, CPU, false); +} - if (TheTriple.isOSWindows()) - assert(0 && "Windows not supported on ARM"); +MCAsmBackend *llvm::createThumbLEAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TT, StringRef CPU) { + return createARMAsmBackend(T, MRI, TT, CPU, true); +} - return new ELFARMAsmBackend(T, TT, Triple(TT).getOS()); +MCAsmBackend *llvm::createThumbBEAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TT, StringRef CPU) { + return createARMAsmBackend(T, MRI, TT, CPU, false); }