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Diffstat (limited to 'contrib/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp | 800 |
1 files changed, 800 insertions, 0 deletions
diff --git a/contrib/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/contrib/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp new file mode 100644 index 0000000..1114635 --- /dev/null +++ b/contrib/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp @@ -0,0 +1,800 @@ +//===-- ARMAsmBackend.cpp - ARM Assembler Backend -------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#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 "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/MCSubtargetInfo.h" +#include "llvm/MC/MCValue.h" +#include "llvm/Support/ELF.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/MachO.h" +#include "llvm/Support/raw_ostream.h" +using namespace llvm; + +namespace { +class ARMELFObjectWriter : public MCELFObjectTargetWriter { +public: + ARMELFObjectWriter(uint8_t OSABI) + : MCELFObjectTargetWriter(/*Is64Bit*/ false, OSABI, ELF::EM_ARM, + /*HasRelocationAddend*/ 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]; +} + +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 ARMAsmBackend::getRelaxedOpcode(unsigned Op) const { + bool HasThumb2 = STI->getFeatureBits()[ARM::FeatureThumb2]; + + 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; + } +} + +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()!"); +} + +void ARMAsmBackend::relaxInstruction(const MCInst &Inst, MCInst &Res) const { + unsigned RelaxedOp = getRelaxedOpcode(Inst.getOpcode()); + + // 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; + } + + // 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 { + const uint16_t Thumb1_16bitNopEncoding = 0x46c0; // using MOV r8,r8 + const uint16_t Thumb2_16bitNopEncoding = 0xbf00; // 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; + uint64_t NumNops = Count / 2; + for (uint64_t i = 0; i != NumNops; ++i) + OW->write16(nopEncoding); + if (Count & 1) + OW->write8(0); + return true; + } + // ARM mode + 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); + // 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; + } + + return true; +} + +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!"); + case FK_Data_1: + 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: + if (!IsPCRel) + Value >>= 16; + // Fallthrough + case ARM::fixup_arm_movw_lo16: { + unsigned Hi4 = (Value & 0xF000) >> 12; + unsigned Lo12 = Value & 0x0FFF; + // inst{19-16} = Hi4; + // inst{11-0} = Lo12; + Value = (Hi4 << 16) | (Lo12); + return Value; + } + case ARM::fixup_t2_movt_hi16: + 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; + unsigned Lo8 = Value & 0x0FF; + // inst{19-16} = Hi4; + // inst{26} = i; + // inst{14-12} = Mid3; + // inst{7-0} = Lo8; + Value = (Hi4 << 16) | (i << 26) | (Mid3 << 12) | (Lo8); + return swapHalfWords(Value, IsLittleEndian); + } + case ARM::fixup_arm_ldst_pcrel_12: + // ARM PC-relative values are offset by 8. + Value -= 4; + // FALLTHROUGH + case ARM::fixup_t2_ldst_pcrel_12: { + // Offset by 4, adjusted by two due to the half-word ordering of thumb. + Value -= 4; + bool isAdd = true; + if ((int64_t)Value < 0) { + Value = -Value; + isAdd = false; + } + 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) + return swapHalfWords(Value, IsLittleEndian); + + return Value; + } + case ARM::fixup_thumb_adr_pcrel_10: + return ((Value - 4) >> 2) & 0xff; + case ARM::fixup_arm_adr_pcrel_12: { + // ARM PC-relative values are offset by 8. + Value -= 8; + unsigned opc = 4; // bits {24-21}. Default to add: 0b0100 + if ((int64_t)Value < 0) { + Value = -Value; + opc = 2; // 0b0010 + } + 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); + } + + case ARM::fixup_t2_adr_pcrel_12: { + Value -= 4; + unsigned opc = 0; + if ((int64_t)Value < 0) { + Value = -Value; + opc = 5; + } + + uint32_t out = (opc << 21); + out |= (Value & 0x800) << 15; + out |= (Value & 0x700) << 4; + out |= (Value & 0x0FF); + + 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<MCSymbolRefExpr>(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 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 + + return swapHalfWords(out, IsLittleEndian); + } + case ARM::fixup_t2_condbranch: { + Value = Value - 4; + Value >>= 1; // Low bit is not encoded. + + uint64_t out = 0; + out |= (Value & 0x80000) << 7; // S bit + out |= (Value & 0x40000) >> 7; // J2 bit + out |= (Value & 0x20000) >> 4; // J1 bit + out |= (Value & 0x1F800) << 5; // imm6 field + out |= (Value & 0x007FF); // imm11 field + + 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 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 xxJxJIIIIIIIIIII + // + // Note that the halfwords are stored high first, low second; so we need + // to transpose the fixup value here to map properly. + 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 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 xxJxJIIIIIIIIII0 + // + // Note that the halfwords are stored high first, low second; so we need + // to transpose the fixup value here to map properly. + uint32_t offset = (Value - 2) >> 2; + if (const MCSymbolRefExpr *SRE = + dyn_cast<MCSymbolRefExpr>(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 + // 'off by 4' is implicitly handled by the half-word ordering of the + // Thumb encoding, so we only need to adjust by 2 here. + return ((Value - 2) >> 2) & 0xff; + case ARM::fixup_arm_thumb_cb: { + // Offset by 4 and don't encode the lower bit, which is always 0. + uint32_t Binary = (Value - 4) >> 1; + return ((Binary & 0x20) << 4) | ((Binary & 0x1f) << 3); + } + case ARM::fixup_arm_thumb_br: + // Offset by 4 and don't encode the lower bit, which is always 0. + return ((Value - 4) >> 1) & 0x7ff; + 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. + case ARM::fixup_t2_pcrel_10: { + // Offset by 4, adjusted by two due to the half-word ordering of thumb. + Value = Value - 4; + bool isAdd = true; + if ((int64_t)Value < 0) { + Value = -Value; + isAdd = false; + } + // These values don't encode the low two bits since they're always zero. + Value >>= 2; + 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) + return swapHalfWords(Value, IsLittleEndian); + + return Value; + } + } +} + +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; + } + } + // 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) { + switch (Kind) { + default: + llvm_unreachable("Unknown fixup kind!"); + + case FK_Data_1: + case ARM::fixup_arm_thumb_bcc: + case ARM::fixup_arm_thumb_cp: + case ARM::fixup_thumb_adr_pcrel_10: + return 1; + + case FK_Data_2: + case ARM::fixup_arm_thumb_br: + 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; + + case FK_Data_4: + 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: + return 4; + + case FK_SecRel_2: + return 2; + case FK_SecRel_4: + return 4; + } +} + +/// 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, Value, IsPCRel, nullptr, IsLittleEndian); + if (!Value) + return; // Doesn't change encoding. + + unsigned Offset = Fixup.getOffset(); + assert(Offset + NumBytes <= DataSize && "Invalid fixup offset!"); + + // 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!"); + } + + // 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, + 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 = + StringSwitch<MachO::CPUSubTypeARM>(TheTriple.getArchName()) + .Cases("armv4t", "thumbv4t", MachO::CPU_SUBTYPE_ARM_V4T) + .Cases("armv5e", "thumbv5e", MachO::CPU_SUBTYPE_ARM_V5TEJ) + .Cases("armv6", "thumbv6", MachO::CPU_SUBTYPE_ARM_V6) + .Cases("armv6m", "thumbv6m", MachO::CPU_SUBTYPE_ARM_V6M) + .Cases("armv7em", "thumbv7em", MachO::CPU_SUBTYPE_ARM_V7EM) + .Cases("armv7k", "thumbv7k", MachO::CPU_SUBTYPE_ARM_V7K) + .Cases("armv7m", "thumbv7m", MachO::CPU_SUBTYPE_ARM_V7M) + .Cases("armv7s", "thumbv7s", MachO::CPU_SUBTYPE_ARM_V7S) + .Default(MachO::CPU_SUBTYPE_ARM_V7); + + 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); +} + +MCAsmBackend *llvm::createThumbLEAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TT, StringRef CPU) { + return createARMAsmBackend(T, MRI, TT, CPU, true); +} + +MCAsmBackend *llvm::createThumbBEAsmBackend(const Target &T, + const MCRegisterInfo &MRI, + const Triple &TT, StringRef CPU) { + return createARMAsmBackend(T, MRI, TT, CPU, false); +} |
