271 lines
8.1 KiB
C++
271 lines
8.1 KiB
C++
//===-- X86ELFObjectWriter.cpp - X86 ELF Writer ---------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/X86FixupKinds.h"
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#include "MCTargetDesc/X86MCTargetDesc.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/ELF.h"
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#include "llvm/Support/ErrorHandling.h"
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using namespace llvm;
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namespace {
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class X86ELFObjectWriter : public MCELFObjectTargetWriter {
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public:
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X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, uint16_t EMachine);
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~X86ELFObjectWriter() override;
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protected:
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unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
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const MCFixup &Fixup, bool IsPCRel) const override;
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};
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}
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X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
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uint16_t EMachine)
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: MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
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// Only i386 and IAMCU use Rel instead of RelA.
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/*HasRelocationAddend*/
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(EMachine != ELF::EM_386) &&
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(EMachine != ELF::EM_IAMCU)) {}
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X86ELFObjectWriter::~X86ELFObjectWriter()
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{}
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enum X86_64RelType { RT64_64, RT64_32, RT64_32S, RT64_16, RT64_8 };
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static X86_64RelType getType64(unsigned Kind,
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MCSymbolRefExpr::VariantKind &Modifier,
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bool &IsPCRel) {
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switch (Kind) {
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default:
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llvm_unreachable("Unimplemented");
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case X86::reloc_global_offset_table8:
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Modifier = MCSymbolRefExpr::VK_GOT;
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IsPCRel = true;
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return RT64_64;
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case FK_Data_8:
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return RT64_64;
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case X86::reloc_signed_4byte:
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if (Modifier == MCSymbolRefExpr::VK_None && !IsPCRel)
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return RT64_32S;
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return RT64_32;
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case X86::reloc_global_offset_table:
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Modifier = MCSymbolRefExpr::VK_GOT;
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IsPCRel = true;
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return RT64_32;
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case FK_Data_4:
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case FK_PCRel_4:
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case X86::reloc_riprel_4byte:
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case X86::reloc_riprel_4byte_movq_load:
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return RT64_32;
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case FK_PCRel_2:
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case FK_Data_2:
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return RT64_16;
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case FK_PCRel_1:
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case FK_Data_1:
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return RT64_8;
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}
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}
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static void checkIs32(MCContext &Ctx, SMLoc Loc, X86_64RelType Type) {
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if (Type != RT64_32)
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Ctx.reportError(Loc,
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"32 bit reloc applied to a field with a different size");
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}
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static unsigned getRelocType64(MCContext &Ctx, SMLoc Loc,
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MCSymbolRefExpr::VariantKind Modifier,
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X86_64RelType Type, bool IsPCRel) {
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switch (Modifier) {
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default:
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llvm_unreachable("Unimplemented");
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case MCSymbolRefExpr::VK_None:
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switch (Type) {
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case RT64_64:
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return IsPCRel ? ELF::R_X86_64_PC64 : ELF::R_X86_64_64;
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case RT64_32:
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return IsPCRel ? ELF::R_X86_64_PC32 : ELF::R_X86_64_32;
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case RT64_32S:
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return ELF::R_X86_64_32S;
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case RT64_16:
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return IsPCRel ? ELF::R_X86_64_PC16 : ELF::R_X86_64_16;
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case RT64_8:
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return IsPCRel ? ELF::R_X86_64_PC8 : ELF::R_X86_64_8;
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}
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case MCSymbolRefExpr::VK_GOT:
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switch (Type) {
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case RT64_64:
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return IsPCRel ? ELF::R_X86_64_GOTPC64 : ELF::R_X86_64_GOT64;
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case RT64_32:
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return IsPCRel ? ELF::R_X86_64_GOTPC32 : ELF::R_X86_64_GOT32;
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case RT64_32S:
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case RT64_16:
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case RT64_8:
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llvm_unreachable("Unimplemented");
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}
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case MCSymbolRefExpr::VK_GOTOFF:
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assert(Type == RT64_64);
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assert(!IsPCRel);
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return ELF::R_X86_64_GOTOFF64;
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case MCSymbolRefExpr::VK_TPOFF:
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assert(!IsPCRel);
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switch (Type) {
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case RT64_64:
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return ELF::R_X86_64_TPOFF64;
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case RT64_32:
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return ELF::R_X86_64_TPOFF32;
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case RT64_32S:
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case RT64_16:
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case RT64_8:
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llvm_unreachable("Unimplemented");
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}
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case MCSymbolRefExpr::VK_DTPOFF:
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assert(!IsPCRel);
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switch (Type) {
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case RT64_64:
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return ELF::R_X86_64_DTPOFF64;
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case RT64_32:
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return ELF::R_X86_64_DTPOFF32;
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case RT64_32S:
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case RT64_16:
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case RT64_8:
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llvm_unreachable("Unimplemented");
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}
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case MCSymbolRefExpr::VK_SIZE:
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assert(!IsPCRel);
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switch (Type) {
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case RT64_64:
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return ELF::R_X86_64_SIZE64;
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case RT64_32:
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return ELF::R_X86_64_SIZE32;
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case RT64_32S:
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case RT64_16:
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case RT64_8:
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llvm_unreachable("Unimplemented");
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}
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case MCSymbolRefExpr::VK_TLSGD:
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checkIs32(Ctx, Loc, Type);
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return ELF::R_X86_64_TLSGD;
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case MCSymbolRefExpr::VK_GOTTPOFF:
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checkIs32(Ctx, Loc, Type);
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return ELF::R_X86_64_GOTTPOFF;
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case MCSymbolRefExpr::VK_TLSLD:
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checkIs32(Ctx, Loc, Type);
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return ELF::R_X86_64_TLSLD;
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case MCSymbolRefExpr::VK_PLT:
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checkIs32(Ctx, Loc, Type);
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return ELF::R_X86_64_PLT32;
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case MCSymbolRefExpr::VK_GOTPCREL:
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checkIs32(Ctx, Loc, Type);
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return ELF::R_X86_64_GOTPCREL;
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}
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}
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enum X86_32RelType { RT32_32, RT32_16, RT32_8 };
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static X86_32RelType getType32(X86_64RelType T) {
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switch (T) {
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case RT64_64:
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llvm_unreachable("Unimplemented");
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case RT64_32:
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case RT64_32S:
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return RT32_32;
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case RT64_16:
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return RT32_16;
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case RT64_8:
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return RT32_8;
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}
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llvm_unreachable("unexpected relocation type!");
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}
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static unsigned getRelocType32(MCSymbolRefExpr::VariantKind Modifier,
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X86_32RelType Type, bool IsPCRel) {
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switch (Modifier) {
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default:
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llvm_unreachable("Unimplemented");
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case MCSymbolRefExpr::VK_None:
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switch (Type) {
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case RT32_32:
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return IsPCRel ? ELF::R_386_PC32 : ELF::R_386_32;
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case RT32_16:
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return IsPCRel ? ELF::R_386_PC16 : ELF::R_386_16;
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case RT32_8:
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return IsPCRel ? ELF::R_386_PC8 : ELF::R_386_8;
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}
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case MCSymbolRefExpr::VK_GOT:
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assert(Type == RT32_32);
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return IsPCRel ? ELF::R_386_GOTPC : ELF::R_386_GOT32;
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case MCSymbolRefExpr::VK_GOTOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_GOTOFF;
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case MCSymbolRefExpr::VK_TPOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_LE_32;
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case MCSymbolRefExpr::VK_DTPOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_LDO_32;
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case MCSymbolRefExpr::VK_TLSGD:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_GD;
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case MCSymbolRefExpr::VK_GOTTPOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_IE_32;
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case MCSymbolRefExpr::VK_PLT:
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assert(Type == RT32_32);
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return ELF::R_386_PLT32;
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case MCSymbolRefExpr::VK_INDNTPOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_IE;
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case MCSymbolRefExpr::VK_NTPOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_LE;
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case MCSymbolRefExpr::VK_GOTNTPOFF:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_GOTIE;
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case MCSymbolRefExpr::VK_TLSLDM:
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assert(Type == RT32_32);
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assert(!IsPCRel);
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return ELF::R_386_TLS_LDM;
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}
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}
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unsigned X86ELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel) const {
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MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
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X86_64RelType Type = getType64(Fixup.getKind(), Modifier, IsPCRel);
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if (getEMachine() == ELF::EM_X86_64)
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return getRelocType64(Ctx, Fixup.getLoc(), Modifier, Type, IsPCRel);
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assert((getEMachine() == ELF::EM_386 || getEMachine() == ELF::EM_IAMCU) &&
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"Unsupported ELF machine type.");
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return getRelocType32(Modifier, getType32(Type), IsPCRel);
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}
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MCObjectWriter *llvm::createX86ELFObjectWriter(raw_pwrite_stream &OS,
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bool IsELF64, uint8_t OSABI,
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uint16_t EMachine) {
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MCELFObjectTargetWriter *MOTW =
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new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
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return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/true);
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}
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