| //===-- ARMELFObjectWriter.cpp - ARM ELF Writer ---------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "MCTargetDesc/ARMFixupKinds.h" |
| #include "MCTargetDesc/ARMMCTargetDesc.h" |
| #include "llvm/BinaryFormat/ELF.h" |
| #include "llvm/MC/MCContext.h" |
| #include "llvm/MC/MCELFObjectWriter.h" |
| #include "llvm/MC/MCExpr.h" |
| #include "llvm/MC/MCFixup.h" |
| #include "llvm/MC/MCObjectWriter.h" |
| #include "llvm/MC/MCValue.h" |
| #include "llvm/Support/ErrorHandling.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include <cstdint> |
| |
| using namespace llvm; |
| |
| namespace { |
| |
| class ARMELFObjectWriter : public MCELFObjectTargetWriter { |
| enum { DefaultEABIVersion = 0x05000000U }; |
| |
| unsigned GetRelocTypeInner(const MCValue &Target, const MCFixup &Fixup, |
| bool IsPCRel, MCContext &Ctx) const; |
| |
| public: |
| ARMELFObjectWriter(uint8_t OSABI); |
| |
| ~ARMELFObjectWriter() override = default; |
| |
| unsigned getRelocType(MCContext &Ctx, const MCValue &Target, |
| const MCFixup &Fixup, bool IsPCRel) const override; |
| |
| bool needsRelocateWithSymbol(const MCSymbol &Sym, |
| unsigned Type) const override; |
| }; |
| |
| } // end anonymous namespace |
| |
| ARMELFObjectWriter::ARMELFObjectWriter(uint8_t OSABI) |
| : MCELFObjectTargetWriter(/*Is64Bit*/ false, OSABI, |
| ELF::EM_ARM, |
| /*HasRelocationAddend*/ false) {} |
| |
| bool ARMELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym, |
| unsigned Type) const { |
| // FIXME: This is extremely conservative. This really needs to use a |
| // whitelist with a clear explanation for why each realocation needs to |
| // point to the symbol, not to the section. |
| switch (Type) { |
| default: |
| return true; |
| |
| case ELF::R_ARM_PREL31: |
| case ELF::R_ARM_ABS32: |
| return false; |
| } |
| } |
| |
| // Need to examine the Fixup when determining whether to |
| // emit the relocation as an explicit symbol or as a section relative |
| // offset |
| unsigned ARMELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target, |
| const MCFixup &Fixup, |
| bool IsPCRel) const { |
| return GetRelocTypeInner(Target, Fixup, IsPCRel, Ctx); |
| } |
| |
| unsigned ARMELFObjectWriter::GetRelocTypeInner(const MCValue &Target, |
| const MCFixup &Fixup, |
| bool IsPCRel, |
| MCContext &Ctx) const { |
| MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant(); |
| |
| if (IsPCRel) { |
| switch ((unsigned)Fixup.getKind()) { |
| default: |
| Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol"); |
| return ELF::R_ARM_NONE; |
| case FK_Data_4: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("Unsupported Modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_REL32; |
| case MCSymbolRefExpr::VK_GOTTPOFF: |
| return ELF::R_ARM_TLS_IE32; |
| case MCSymbolRefExpr::VK_ARM_GOT_PREL: |
| return ELF::R_ARM_GOT_PREL; |
| case MCSymbolRefExpr::VK_ARM_PREL31: |
| return ELF::R_ARM_PREL31; |
| } |
| case ARM::fixup_arm_blx: |
| case ARM::fixup_arm_uncondbl: |
| switch (Modifier) { |
| case MCSymbolRefExpr::VK_PLT: |
| return ELF::R_ARM_CALL; |
| case MCSymbolRefExpr::VK_TLSCALL: |
| return ELF::R_ARM_TLS_CALL; |
| default: |
| return ELF::R_ARM_CALL; |
| } |
| case ARM::fixup_arm_condbl: |
| case ARM::fixup_arm_condbranch: |
| case ARM::fixup_arm_uncondbranch: |
| return ELF::R_ARM_JUMP24; |
| case ARM::fixup_t2_condbranch: |
| return ELF::R_ARM_THM_JUMP19; |
| case ARM::fixup_t2_uncondbranch: |
| return ELF::R_ARM_THM_JUMP24; |
| case ARM::fixup_arm_movt_hi16: |
| return ELF::R_ARM_MOVT_PREL; |
| case ARM::fixup_arm_movw_lo16: |
| return ELF::R_ARM_MOVW_PREL_NC; |
| case ARM::fixup_t2_movt_hi16: |
| return ELF::R_ARM_THM_MOVT_PREL; |
| case ARM::fixup_t2_movw_lo16: |
| return ELF::R_ARM_THM_MOVW_PREL_NC; |
| case ARM::fixup_arm_thumb_br: |
| return ELF::R_ARM_THM_JUMP11; |
| case ARM::fixup_arm_thumb_bcc: |
| return ELF::R_ARM_THM_JUMP8; |
| case ARM::fixup_arm_thumb_bl: |
| case ARM::fixup_arm_thumb_blx: |
| switch (Modifier) { |
| case MCSymbolRefExpr::VK_TLSCALL: |
| return ELF::R_ARM_THM_TLS_CALL; |
| default: |
| return ELF::R_ARM_THM_CALL; |
| } |
| } |
| } |
| switch ((unsigned)Fixup.getKind()) { |
| default: |
| Ctx.reportFatalError(Fixup.getLoc(), "unsupported relocation on symbol"); |
| return ELF::R_ARM_NONE; |
| case FK_Data_1: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("unsupported Modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_ABS8; |
| } |
| case FK_Data_2: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("unsupported modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_ABS16; |
| } |
| case FK_Data_4: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("Unsupported Modifier"); |
| case MCSymbolRefExpr::VK_ARM_NONE: |
| return ELF::R_ARM_NONE; |
| case MCSymbolRefExpr::VK_GOT: |
| return ELF::R_ARM_GOT_BREL; |
| case MCSymbolRefExpr::VK_TLSGD: |
| return ELF::R_ARM_TLS_GD32; |
| case MCSymbolRefExpr::VK_TPOFF: |
| return ELF::R_ARM_TLS_LE32; |
| case MCSymbolRefExpr::VK_GOTTPOFF: |
| return ELF::R_ARM_TLS_IE32; |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_ABS32; |
| case MCSymbolRefExpr::VK_GOTOFF: |
| return ELF::R_ARM_GOTOFF32; |
| case MCSymbolRefExpr::VK_ARM_GOT_PREL: |
| return ELF::R_ARM_GOT_PREL; |
| case MCSymbolRefExpr::VK_ARM_TARGET1: |
| return ELF::R_ARM_TARGET1; |
| case MCSymbolRefExpr::VK_ARM_TARGET2: |
| return ELF::R_ARM_TARGET2; |
| case MCSymbolRefExpr::VK_ARM_PREL31: |
| return ELF::R_ARM_PREL31; |
| case MCSymbolRefExpr::VK_ARM_SBREL: |
| return ELF::R_ARM_SBREL32; |
| case MCSymbolRefExpr::VK_ARM_TLSLDO: |
| return ELF::R_ARM_TLS_LDO32; |
| case MCSymbolRefExpr::VK_TLSCALL: |
| return ELF::R_ARM_TLS_CALL; |
| case MCSymbolRefExpr::VK_TLSDESC: |
| return ELF::R_ARM_TLS_GOTDESC; |
| case MCSymbolRefExpr::VK_TLSLDM: |
| return ELF::R_ARM_TLS_LDM32; |
| case MCSymbolRefExpr::VK_ARM_TLSDESCSEQ: |
| return ELF::R_ARM_TLS_DESCSEQ; |
| } |
| case ARM::fixup_arm_condbranch: |
| case ARM::fixup_arm_uncondbranch: |
| return ELF::R_ARM_JUMP24; |
| case ARM::fixup_arm_movt_hi16: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("Unsupported Modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_MOVT_ABS; |
| case MCSymbolRefExpr::VK_ARM_SBREL: |
| return ELF::R_ARM_MOVT_BREL; |
| } |
| case ARM::fixup_arm_movw_lo16: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("Unsupported Modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_MOVW_ABS_NC; |
| case MCSymbolRefExpr::VK_ARM_SBREL: |
| return ELF::R_ARM_MOVW_BREL_NC; |
| } |
| case ARM::fixup_t2_movt_hi16: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("Unsupported Modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_THM_MOVT_ABS; |
| case MCSymbolRefExpr::VK_ARM_SBREL: |
| return ELF::R_ARM_THM_MOVT_BREL; |
| } |
| case ARM::fixup_t2_movw_lo16: |
| switch (Modifier) { |
| default: |
| llvm_unreachable("Unsupported Modifier"); |
| case MCSymbolRefExpr::VK_None: |
| return ELF::R_ARM_THM_MOVW_ABS_NC; |
| case MCSymbolRefExpr::VK_ARM_SBREL: |
| return ELF::R_ARM_THM_MOVW_BREL_NC; |
| } |
| } |
| } |
| |
| std::unique_ptr<MCObjectTargetWriter> |
| llvm::createARMELFObjectWriter(uint8_t OSABI) { |
| return llvm::make_unique<ARMELFObjectWriter>(OSABI); |
| } |