| //===- ARM.cpp ------------------------------------------------------------===// |
| // |
| // 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 "InputFiles.h" |
| #include "Symbols.h" |
| #include "SyntheticSections.h" |
| #include "Target.h" |
| #include "Thunks.h" |
| #include "lld/Common/ErrorHandler.h" |
| #include "llvm/Object/ELF.h" |
| #include "llvm/Support/Endian.h" |
| |
| using namespace llvm; |
| using namespace llvm::support::endian; |
| using namespace llvm::ELF; |
| using namespace lld; |
| using namespace lld::elf; |
| |
| namespace { |
| class ARM final : public TargetInfo { |
| public: |
| ARM(); |
| uint32_t calcEFlags() const override; |
| RelExpr getRelExpr(RelType Type, const Symbol &S, |
| const uint8_t *Loc) const override; |
| RelType getDynRel(RelType Type) const override; |
| int64_t getImplicitAddend(const uint8_t *Buf, RelType Type) const override; |
| void writeGotPlt(uint8_t *Buf, const Symbol &S) const override; |
| void writeIgotPlt(uint8_t *Buf, const Symbol &S) const override; |
| void writePltHeader(uint8_t *Buf) const override; |
| void writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, uint64_t PltEntryAddr, |
| int32_t Index, unsigned RelOff) const override; |
| void addPltSymbols(InputSection &IS, uint64_t Off) const override; |
| void addPltHeaderSymbols(InputSection &ISD) const override; |
| bool needsThunk(RelExpr Expr, RelType Type, const InputFile *File, |
| uint64_t BranchAddr, const Symbol &S) const override; |
| uint32_t getThunkSectionSpacing() const override; |
| bool inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const override; |
| void relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const override; |
| }; |
| } // namespace |
| |
| ARM::ARM() { |
| CopyRel = R_ARM_COPY; |
| RelativeRel = R_ARM_RELATIVE; |
| IRelativeRel = R_ARM_IRELATIVE; |
| GotRel = R_ARM_GLOB_DAT; |
| NoneRel = R_ARM_NONE; |
| PltRel = R_ARM_JUMP_SLOT; |
| TlsGotRel = R_ARM_TLS_TPOFF32; |
| TlsModuleIndexRel = R_ARM_TLS_DTPMOD32; |
| TlsOffsetRel = R_ARM_TLS_DTPOFF32; |
| GotBaseSymInGotPlt = false; |
| PltEntrySize = 16; |
| PltHeaderSize = 32; |
| TrapInstr = {0xd4, 0xd4, 0xd4, 0xd4}; |
| NeedsThunks = true; |
| } |
| |
| uint32_t ARM::calcEFlags() const { |
| // The ABIFloatType is used by loaders to detect the floating point calling |
| // convention. |
| uint32_t ABIFloatType = 0; |
| if (Config->ARMVFPArgs == ARMVFPArgKind::Base || |
| Config->ARMVFPArgs == ARMVFPArgKind::Default) |
| ABIFloatType = EF_ARM_ABI_FLOAT_SOFT; |
| else if (Config->ARMVFPArgs == ARMVFPArgKind::VFP) |
| ABIFloatType = EF_ARM_ABI_FLOAT_HARD; |
| |
| // We don't currently use any features incompatible with EF_ARM_EABI_VER5, |
| // but we don't have any firm guarantees of conformance. Linux AArch64 |
| // kernels (as of 2016) require an EABI version to be set. |
| return EF_ARM_EABI_VER5 | ABIFloatType; |
| } |
| |
| RelExpr ARM::getRelExpr(RelType Type, const Symbol &S, |
| const uint8_t *Loc) const { |
| switch (Type) { |
| case R_ARM_THM_JUMP11: |
| return R_PC; |
| case R_ARM_CALL: |
| case R_ARM_JUMP24: |
| case R_ARM_PC24: |
| case R_ARM_PLT32: |
| case R_ARM_PREL31: |
| case R_ARM_THM_JUMP19: |
| case R_ARM_THM_JUMP24: |
| case R_ARM_THM_CALL: |
| return R_PLT_PC; |
| case R_ARM_GOTOFF32: |
| // (S + A) - GOT_ORG |
| return R_GOTREL; |
| case R_ARM_GOT_BREL: |
| // GOT(S) + A - GOT_ORG |
| return R_GOT_OFF; |
| case R_ARM_GOT_PREL: |
| case R_ARM_TLS_IE32: |
| // GOT(S) + A - P |
| return R_GOT_PC; |
| case R_ARM_SBREL32: |
| return R_ARM_SBREL; |
| case R_ARM_TARGET1: |
| return Config->Target1Rel ? R_PC : R_ABS; |
| case R_ARM_TARGET2: |
| if (Config->Target2 == Target2Policy::Rel) |
| return R_PC; |
| if (Config->Target2 == Target2Policy::Abs) |
| return R_ABS; |
| return R_GOT_PC; |
| case R_ARM_TLS_GD32: |
| return R_TLSGD_PC; |
| case R_ARM_TLS_LDM32: |
| return R_TLSLD_PC; |
| case R_ARM_BASE_PREL: |
| // B(S) + A - P |
| // FIXME: currently B(S) assumed to be .got, this may not hold for all |
| // platforms. |
| return R_GOTONLY_PC; |
| case R_ARM_MOVW_PREL_NC: |
| case R_ARM_MOVT_PREL: |
| case R_ARM_REL32: |
| case R_ARM_THM_MOVW_PREL_NC: |
| case R_ARM_THM_MOVT_PREL: |
| return R_PC; |
| case R_ARM_NONE: |
| return R_NONE; |
| case R_ARM_TLS_LE32: |
| return R_TLS; |
| case R_ARM_V4BX: |
| // V4BX is just a marker to indicate there's a "bx rN" instruction at the |
| // given address. It can be used to implement a special linker mode which |
| // rewrites ARMv4T inputs to ARMv4. Since we support only ARMv4 input and |
| // not ARMv4 output, we can just ignore it. |
| return R_HINT; |
| default: |
| return R_ABS; |
| } |
| } |
| |
| RelType ARM::getDynRel(RelType Type) const { |
| if ((Type == R_ARM_ABS32) || (Type == R_ARM_TARGET1 && !Config->Target1Rel)) |
| return R_ARM_ABS32; |
| return R_ARM_NONE; |
| } |
| |
| void ARM::writeGotPlt(uint8_t *Buf, const Symbol &) const { |
| write32le(Buf, In.Plt->getVA()); |
| } |
| |
| void ARM::writeIgotPlt(uint8_t *Buf, const Symbol &S) const { |
| // An ARM entry is the address of the ifunc resolver function. |
| write32le(Buf, S.getVA()); |
| } |
| |
| // Long form PLT Header that does not have any restrictions on the displacement |
| // of the .plt from the .plt.got. |
| static void writePltHeaderLong(uint8_t *Buf) { |
| const uint8_t PltData[] = { |
| 0x04, 0xe0, 0x2d, 0xe5, // str lr, [sp,#-4]! |
| 0x04, 0xe0, 0x9f, 0xe5, // ldr lr, L2 |
| 0x0e, 0xe0, 0x8f, 0xe0, // L1: add lr, pc, lr |
| 0x08, 0xf0, 0xbe, 0xe5, // ldr pc, [lr, #8] |
| 0x00, 0x00, 0x00, 0x00, // L2: .word &(.got.plt) - L1 - 8 |
| 0xd4, 0xd4, 0xd4, 0xd4, // Pad to 32-byte boundary |
| 0xd4, 0xd4, 0xd4, 0xd4, // Pad to 32-byte boundary |
| 0xd4, 0xd4, 0xd4, 0xd4}; |
| memcpy(Buf, PltData, sizeof(PltData)); |
| uint64_t GotPlt = In.GotPlt->getVA(); |
| uint64_t L1 = In.Plt->getVA() + 8; |
| write32le(Buf + 16, GotPlt - L1 - 8); |
| } |
| |
| // The default PLT header requires the .plt.got to be within 128 Mb of the |
| // .plt in the positive direction. |
| void ARM::writePltHeader(uint8_t *Buf) const { |
| // Use a similar sequence to that in writePlt(), the difference is the calling |
| // conventions mean we use lr instead of ip. The PLT entry is responsible for |
| // saving lr on the stack, the dynamic loader is responsible for reloading |
| // it. |
| const uint32_t PltData[] = { |
| 0xe52de004, // L1: str lr, [sp,#-4]! |
| 0xe28fe600, // add lr, pc, #0x0NN00000 &(.got.plt - L1 - 4) |
| 0xe28eea00, // add lr, lr, #0x000NN000 &(.got.plt - L1 - 4) |
| 0xe5bef000, // ldr pc, [lr, #0x00000NNN] &(.got.plt -L1 - 4) |
| }; |
| |
| uint64_t Offset = In.GotPlt->getVA() - In.Plt->getVA() - 4; |
| if (!llvm::isUInt<27>(Offset)) { |
| // We cannot encode the Offset, use the long form. |
| writePltHeaderLong(Buf); |
| return; |
| } |
| write32le(Buf + 0, PltData[0]); |
| write32le(Buf + 4, PltData[1] | ((Offset >> 20) & 0xff)); |
| write32le(Buf + 8, PltData[2] | ((Offset >> 12) & 0xff)); |
| write32le(Buf + 12, PltData[3] | (Offset & 0xfff)); |
| memcpy(Buf + 16, TrapInstr.data(), 4); // Pad to 32-byte boundary |
| memcpy(Buf + 20, TrapInstr.data(), 4); |
| memcpy(Buf + 24, TrapInstr.data(), 4); |
| memcpy(Buf + 28, TrapInstr.data(), 4); |
| } |
| |
| void ARM::addPltHeaderSymbols(InputSection &IS) const { |
| addSyntheticLocal("$a", STT_NOTYPE, 0, 0, IS); |
| addSyntheticLocal("$d", STT_NOTYPE, 16, 0, IS); |
| } |
| |
| // Long form PLT entries that do not have any restrictions on the displacement |
| // of the .plt from the .plt.got. |
| static void writePltLong(uint8_t *Buf, uint64_t GotPltEntryAddr, |
| uint64_t PltEntryAddr, int32_t Index, |
| unsigned RelOff) { |
| const uint8_t PltData[] = { |
| 0x04, 0xc0, 0x9f, 0xe5, // ldr ip, L2 |
| 0x0f, 0xc0, 0x8c, 0xe0, // L1: add ip, ip, pc |
| 0x00, 0xf0, 0x9c, 0xe5, // ldr pc, [ip] |
| 0x00, 0x00, 0x00, 0x00, // L2: .word Offset(&(.plt.got) - L1 - 8 |
| }; |
| memcpy(Buf, PltData, sizeof(PltData)); |
| uint64_t L1 = PltEntryAddr + 4; |
| write32le(Buf + 12, GotPltEntryAddr - L1 - 8); |
| } |
| |
| // The default PLT entries require the .plt.got to be within 128 Mb of the |
| // .plt in the positive direction. |
| void ARM::writePlt(uint8_t *Buf, uint64_t GotPltEntryAddr, |
| uint64_t PltEntryAddr, int32_t Index, |
| unsigned RelOff) const { |
| // The PLT entry is similar to the example given in Appendix A of ELF for |
| // the Arm Architecture. Instead of using the Group Relocations to find the |
| // optimal rotation for the 8-bit immediate used in the add instructions we |
| // hard code the most compact rotations for simplicity. This saves a load |
| // instruction over the long plt sequences. |
| const uint32_t PltData[] = { |
| 0xe28fc600, // L1: add ip, pc, #0x0NN00000 Offset(&(.plt.got) - L1 - 8 |
| 0xe28cca00, // add ip, ip, #0x000NN000 Offset(&(.plt.got) - L1 - 8 |
| 0xe5bcf000, // ldr pc, [ip, #0x00000NNN] Offset(&(.plt.got) - L1 - 8 |
| }; |
| |
| uint64_t Offset = GotPltEntryAddr - PltEntryAddr - 8; |
| if (!llvm::isUInt<27>(Offset)) { |
| // We cannot encode the Offset, use the long form. |
| writePltLong(Buf, GotPltEntryAddr, PltEntryAddr, Index, RelOff); |
| return; |
| } |
| write32le(Buf + 0, PltData[0] | ((Offset >> 20) & 0xff)); |
| write32le(Buf + 4, PltData[1] | ((Offset >> 12) & 0xff)); |
| write32le(Buf + 8, PltData[2] | (Offset & 0xfff)); |
| memcpy(Buf + 12, TrapInstr.data(), 4); // Pad to 16-byte boundary |
| } |
| |
| void ARM::addPltSymbols(InputSection &IS, uint64_t Off) const { |
| addSyntheticLocal("$a", STT_NOTYPE, Off, 0, IS); |
| addSyntheticLocal("$d", STT_NOTYPE, Off + 12, 0, IS); |
| } |
| |
| bool ARM::needsThunk(RelExpr Expr, RelType Type, const InputFile *File, |
| uint64_t BranchAddr, const Symbol &S) const { |
| // If S is an undefined weak symbol and does not have a PLT entry then it |
| // will be resolved as a branch to the next instruction. |
| if (S.isUndefWeak() && !S.isInPlt()) |
| return false; |
| // A state change from ARM to Thumb and vice versa must go through an |
| // interworking thunk if the relocation type is not R_ARM_CALL or |
| // R_ARM_THM_CALL. |
| switch (Type) { |
| case R_ARM_PC24: |
| case R_ARM_PLT32: |
| case R_ARM_JUMP24: |
| // Source is ARM, all PLT entries are ARM so no interworking required. |
| // Otherwise we need to interwork if Symbol has bit 0 set (Thumb). |
| if (Expr == R_PC && ((S.getVA() & 1) == 1)) |
| return true; |
| LLVM_FALLTHROUGH; |
| case R_ARM_CALL: { |
| uint64_t Dst = (Expr == R_PLT_PC) ? S.getPltVA() : S.getVA(); |
| return !inBranchRange(Type, BranchAddr, Dst); |
| } |
| case R_ARM_THM_JUMP19: |
| case R_ARM_THM_JUMP24: |
| // Source is Thumb, all PLT entries are ARM so interworking is required. |
| // Otherwise we need to interwork if Symbol has bit 0 clear (ARM). |
| if (Expr == R_PLT_PC || ((S.getVA() & 1) == 0)) |
| return true; |
| LLVM_FALLTHROUGH; |
| case R_ARM_THM_CALL: { |
| uint64_t Dst = (Expr == R_PLT_PC) ? S.getPltVA() : S.getVA(); |
| return !inBranchRange(Type, BranchAddr, Dst); |
| } |
| } |
| return false; |
| } |
| |
| uint32_t ARM::getThunkSectionSpacing() const { |
| // The placing of pre-created ThunkSections is controlled by the value |
| // ThunkSectionSpacing returned by getThunkSectionSpacing(). The aim is to |
| // place the ThunkSection such that all branches from the InputSections |
| // prior to the ThunkSection can reach a Thunk placed at the end of the |
| // ThunkSection. Graphically: |
| // | up to ThunkSectionSpacing .text input sections | |
| // | ThunkSection | |
| // | up to ThunkSectionSpacing .text input sections | |
| // | ThunkSection | |
| |
| // Pre-created ThunkSections are spaced roughly 16MiB apart on ARMv7. This |
| // is to match the most common expected case of a Thumb 2 encoded BL, BLX or |
| // B.W: |
| // ARM B, BL, BLX range +/- 32MiB |
| // Thumb B.W, BL, BLX range +/- 16MiB |
| // Thumb B<cc>.W range +/- 1MiB |
| // If a branch cannot reach a pre-created ThunkSection a new one will be |
| // created so we can handle the rare cases of a Thumb 2 conditional branch. |
| // We intentionally use a lower size for ThunkSectionSpacing than the maximum |
| // branch range so the end of the ThunkSection is more likely to be within |
| // range of the branch instruction that is furthest away. The value we shorten |
| // ThunkSectionSpacing by is set conservatively to allow us to create 16,384 |
| // 12 byte Thunks at any offset in a ThunkSection without risk of a branch to |
| // one of the Thunks going out of range. |
| |
| // On Arm the ThunkSectionSpacing depends on the range of the Thumb Branch |
| // range. On earlier Architectures such as ARMv4, ARMv5 and ARMv6 (except |
| // ARMv6T2) the range is +/- 4MiB. |
| |
| return (Config->ARMJ1J2BranchEncoding) ? 0x1000000 - 0x30000 |
| : 0x400000 - 0x7500; |
| } |
| |
| bool ARM::inBranchRange(RelType Type, uint64_t Src, uint64_t Dst) const { |
| uint64_t Range; |
| uint64_t InstrSize; |
| |
| switch (Type) { |
| case R_ARM_PC24: |
| case R_ARM_PLT32: |
| case R_ARM_JUMP24: |
| case R_ARM_CALL: |
| Range = 0x2000000; |
| InstrSize = 4; |
| break; |
| case R_ARM_THM_JUMP19: |
| Range = 0x100000; |
| InstrSize = 2; |
| break; |
| case R_ARM_THM_JUMP24: |
| case R_ARM_THM_CALL: |
| Range = Config->ARMJ1J2BranchEncoding ? 0x1000000 : 0x400000; |
| InstrSize = 2; |
| break; |
| default: |
| return true; |
| } |
| // PC at Src is 2 instructions ahead, immediate of branch is signed |
| if (Src > Dst) |
| Range -= 2 * InstrSize; |
| else |
| Range += InstrSize; |
| |
| if ((Dst & 0x1) == 0) |
| // Destination is ARM, if ARM caller then Src is already 4-byte aligned. |
| // If Thumb Caller (BLX) the Src address has bottom 2 bits cleared to ensure |
| // destination will be 4 byte aligned. |
| Src &= ~0x3; |
| else |
| // Bit 0 == 1 denotes Thumb state, it is not part of the range |
| Dst &= ~0x1; |
| |
| uint64_t Distance = (Src > Dst) ? Src - Dst : Dst - Src; |
| return Distance <= Range; |
| } |
| |
| void ARM::relocateOne(uint8_t *Loc, RelType Type, uint64_t Val) const { |
| switch (Type) { |
| case R_ARM_ABS32: |
| case R_ARM_BASE_PREL: |
| case R_ARM_GLOB_DAT: |
| case R_ARM_GOTOFF32: |
| case R_ARM_GOT_BREL: |
| case R_ARM_GOT_PREL: |
| case R_ARM_REL32: |
| case R_ARM_RELATIVE: |
| case R_ARM_SBREL32: |
| case R_ARM_TARGET1: |
| case R_ARM_TARGET2: |
| case R_ARM_TLS_GD32: |
| case R_ARM_TLS_IE32: |
| case R_ARM_TLS_LDM32: |
| case R_ARM_TLS_LDO32: |
| case R_ARM_TLS_LE32: |
| case R_ARM_TLS_TPOFF32: |
| case R_ARM_TLS_DTPOFF32: |
| write32le(Loc, Val); |
| break; |
| case R_ARM_TLS_DTPMOD32: |
| write32le(Loc, 1); |
| break; |
| case R_ARM_PREL31: |
| checkInt(Loc, Val, 31, Type); |
| write32le(Loc, (read32le(Loc) & 0x80000000) | (Val & ~0x80000000)); |
| break; |
| case R_ARM_CALL: |
| // R_ARM_CALL is used for BL and BLX instructions, depending on the |
| // value of bit 0 of Val, we must select a BL or BLX instruction |
| if (Val & 1) { |
| // If bit 0 of Val is 1 the target is Thumb, we must select a BLX. |
| // The BLX encoding is 0xfa:H:imm24 where Val = imm24:H:'1' |
| checkInt(Loc, Val, 26, Type); |
| write32le(Loc, 0xfa000000 | // opcode |
| ((Val & 2) << 23) | // H |
| ((Val >> 2) & 0x00ffffff)); // imm24 |
| break; |
| } |
| if ((read32le(Loc) & 0xfe000000) == 0xfa000000) |
| // BLX (always unconditional) instruction to an ARM Target, select an |
| // unconditional BL. |
| write32le(Loc, 0xeb000000 | (read32le(Loc) & 0x00ffffff)); |
| // fall through as BL encoding is shared with B |
| LLVM_FALLTHROUGH; |
| case R_ARM_JUMP24: |
| case R_ARM_PC24: |
| case R_ARM_PLT32: |
| checkInt(Loc, Val, 26, Type); |
| write32le(Loc, (read32le(Loc) & ~0x00ffffff) | ((Val >> 2) & 0x00ffffff)); |
| break; |
| case R_ARM_THM_JUMP11: |
| checkInt(Loc, Val, 12, Type); |
| write16le(Loc, (read32le(Loc) & 0xf800) | ((Val >> 1) & 0x07ff)); |
| break; |
| case R_ARM_THM_JUMP19: |
| // Encoding T3: Val = S:J2:J1:imm6:imm11:0 |
| checkInt(Loc, Val, 21, Type); |
| write16le(Loc, |
| (read16le(Loc) & 0xfbc0) | // opcode cond |
| ((Val >> 10) & 0x0400) | // S |
| ((Val >> 12) & 0x003f)); // imm6 |
| write16le(Loc + 2, |
| 0x8000 | // opcode |
| ((Val >> 8) & 0x0800) | // J2 |
| ((Val >> 5) & 0x2000) | // J1 |
| ((Val >> 1) & 0x07ff)); // imm11 |
| break; |
| case R_ARM_THM_CALL: |
| // R_ARM_THM_CALL is used for BL and BLX instructions, depending on the |
| // value of bit 0 of Val, we must select a BL or BLX instruction |
| if ((Val & 1) == 0) { |
| // Ensure BLX destination is 4-byte aligned. As BLX instruction may |
| // only be two byte aligned. This must be done before overflow check |
| Val = alignTo(Val, 4); |
| } |
| // Bit 12 is 0 for BLX, 1 for BL |
| write16le(Loc + 2, (read16le(Loc + 2) & ~0x1000) | (Val & 1) << 12); |
| if (!Config->ARMJ1J2BranchEncoding) { |
| // Older Arm architectures do not support R_ARM_THM_JUMP24 and have |
| // different encoding rules and range due to J1 and J2 always being 1. |
| checkInt(Loc, Val, 23, Type); |
| write16le(Loc, |
| 0xf000 | // opcode |
| ((Val >> 12) & 0x07ff)); // imm11 |
| write16le(Loc + 2, |
| (read16le(Loc + 2) & 0xd000) | // opcode |
| 0x2800 | // J1 == J2 == 1 |
| ((Val >> 1) & 0x07ff)); // imm11 |
| break; |
| } |
| // Fall through as rest of encoding is the same as B.W |
| LLVM_FALLTHROUGH; |
| case R_ARM_THM_JUMP24: |
| // Encoding B T4, BL T1, BLX T2: Val = S:I1:I2:imm10:imm11:0 |
| checkInt(Loc, Val, 25, Type); |
| write16le(Loc, |
| 0xf000 | // opcode |
| ((Val >> 14) & 0x0400) | // S |
| ((Val >> 12) & 0x03ff)); // imm10 |
| write16le(Loc + 2, |
| (read16le(Loc + 2) & 0xd000) | // opcode |
| (((~(Val >> 10)) ^ (Val >> 11)) & 0x2000) | // J1 |
| (((~(Val >> 11)) ^ (Val >> 13)) & 0x0800) | // J2 |
| ((Val >> 1) & 0x07ff)); // imm11 |
| break; |
| case R_ARM_MOVW_ABS_NC: |
| case R_ARM_MOVW_PREL_NC: |
| write32le(Loc, (read32le(Loc) & ~0x000f0fff) | ((Val & 0xf000) << 4) | |
| (Val & 0x0fff)); |
| break; |
| case R_ARM_MOVT_ABS: |
| case R_ARM_MOVT_PREL: |
| write32le(Loc, (read32le(Loc) & ~0x000f0fff) | |
| (((Val >> 16) & 0xf000) << 4) | ((Val >> 16) & 0xfff)); |
| break; |
| case R_ARM_THM_MOVT_ABS: |
| case R_ARM_THM_MOVT_PREL: |
| // Encoding T1: A = imm4:i:imm3:imm8 |
| write16le(Loc, |
| 0xf2c0 | // opcode |
| ((Val >> 17) & 0x0400) | // i |
| ((Val >> 28) & 0x000f)); // imm4 |
| write16le(Loc + 2, |
| (read16le(Loc + 2) & 0x8f00) | // opcode |
| ((Val >> 12) & 0x7000) | // imm3 |
| ((Val >> 16) & 0x00ff)); // imm8 |
| break; |
| case R_ARM_THM_MOVW_ABS_NC: |
| case R_ARM_THM_MOVW_PREL_NC: |
| // Encoding T3: A = imm4:i:imm3:imm8 |
| write16le(Loc, |
| 0xf240 | // opcode |
| ((Val >> 1) & 0x0400) | // i |
| ((Val >> 12) & 0x000f)); // imm4 |
| write16le(Loc + 2, |
| (read16le(Loc + 2) & 0x8f00) | // opcode |
| ((Val << 4) & 0x7000) | // imm3 |
| (Val & 0x00ff)); // imm8 |
| break; |
| default: |
| error(getErrorLocation(Loc) + "unrecognized relocation " + toString(Type)); |
| } |
| } |
| |
| int64_t ARM::getImplicitAddend(const uint8_t *Buf, RelType Type) const { |
| switch (Type) { |
| default: |
| return 0; |
| case R_ARM_ABS32: |
| case R_ARM_BASE_PREL: |
| case R_ARM_GOTOFF32: |
| case R_ARM_GOT_BREL: |
| case R_ARM_GOT_PREL: |
| case R_ARM_REL32: |
| case R_ARM_TARGET1: |
| case R_ARM_TARGET2: |
| case R_ARM_TLS_GD32: |
| case R_ARM_TLS_LDM32: |
| case R_ARM_TLS_LDO32: |
| case R_ARM_TLS_IE32: |
| case R_ARM_TLS_LE32: |
| return SignExtend64<32>(read32le(Buf)); |
| case R_ARM_PREL31: |
| return SignExtend64<31>(read32le(Buf)); |
| case R_ARM_CALL: |
| case R_ARM_JUMP24: |
| case R_ARM_PC24: |
| case R_ARM_PLT32: |
| return SignExtend64<26>(read32le(Buf) << 2); |
| case R_ARM_THM_JUMP11: |
| return SignExtend64<12>(read16le(Buf) << 1); |
| case R_ARM_THM_JUMP19: { |
| // Encoding T3: A = S:J2:J1:imm10:imm6:0 |
| uint16_t Hi = read16le(Buf); |
| uint16_t Lo = read16le(Buf + 2); |
| return SignExtend64<20>(((Hi & 0x0400) << 10) | // S |
| ((Lo & 0x0800) << 8) | // J2 |
| ((Lo & 0x2000) << 5) | // J1 |
| ((Hi & 0x003f) << 12) | // imm6 |
| ((Lo & 0x07ff) << 1)); // imm11:0 |
| } |
| case R_ARM_THM_CALL: |
| if (!Config->ARMJ1J2BranchEncoding) { |
| // Older Arm architectures do not support R_ARM_THM_JUMP24 and have |
| // different encoding rules and range due to J1 and J2 always being 1. |
| uint16_t Hi = read16le(Buf); |
| uint16_t Lo = read16le(Buf + 2); |
| return SignExtend64<22>(((Hi & 0x7ff) << 12) | // imm11 |
| ((Lo & 0x7ff) << 1)); // imm11:0 |
| break; |
| } |
| LLVM_FALLTHROUGH; |
| case R_ARM_THM_JUMP24: { |
| // Encoding B T4, BL T1, BLX T2: A = S:I1:I2:imm10:imm11:0 |
| // I1 = NOT(J1 EOR S), I2 = NOT(J2 EOR S) |
| uint16_t Hi = read16le(Buf); |
| uint16_t Lo = read16le(Buf + 2); |
| return SignExtend64<24>(((Hi & 0x0400) << 14) | // S |
| (~((Lo ^ (Hi << 3)) << 10) & 0x00800000) | // I1 |
| (~((Lo ^ (Hi << 1)) << 11) & 0x00400000) | // I2 |
| ((Hi & 0x003ff) << 12) | // imm0 |
| ((Lo & 0x007ff) << 1)); // imm11:0 |
| } |
| // ELF for the ARM Architecture 4.6.1.1 the implicit addend for MOVW and |
| // MOVT is in the range -32768 <= A < 32768 |
| case R_ARM_MOVW_ABS_NC: |
| case R_ARM_MOVT_ABS: |
| case R_ARM_MOVW_PREL_NC: |
| case R_ARM_MOVT_PREL: { |
| uint64_t Val = read32le(Buf) & 0x000f0fff; |
| return SignExtend64<16>(((Val & 0x000f0000) >> 4) | (Val & 0x00fff)); |
| } |
| case R_ARM_THM_MOVW_ABS_NC: |
| case R_ARM_THM_MOVT_ABS: |
| case R_ARM_THM_MOVW_PREL_NC: |
| case R_ARM_THM_MOVT_PREL: { |
| // Encoding T3: A = imm4:i:imm3:imm8 |
| uint16_t Hi = read16le(Buf); |
| uint16_t Lo = read16le(Buf + 2); |
| return SignExtend64<16>(((Hi & 0x000f) << 12) | // imm4 |
| ((Hi & 0x0400) << 1) | // i |
| ((Lo & 0x7000) >> 4) | // imm3 |
| (Lo & 0x00ff)); // imm8 |
| } |
| } |
| } |
| |
| TargetInfo *elf::getARMTargetInfo() { |
| static ARM Target; |
| return &Target; |
| } |
