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https://github.com/c64scene-ar/llvm-6502.git
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fd506efec6
is used in cases where global symbols are directly represented in the GOT and we use an offset into the global offset table. This patch adds direct object support for R_MIPS_GOT_DISP. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160183 91177308-0d34-0410-b5e6-96231b3b80d8
271 lines
9.0 KiB
C++
271 lines
9.0 KiB
C++
//===-- MipsELFObjectWriter.cpp - Mips 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/MipsBaseInfo.h"
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#include "MCTargetDesc/MipsFixupKinds.h"
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#include "MCTargetDesc/MipsMCTargetDesc.h"
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#include "llvm/MC/MCAssembler.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/MCSection.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/ErrorHandling.h"
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#include <list>
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using namespace llvm;
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namespace {
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struct RelEntry {
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RelEntry(const ELFRelocationEntry &R, const MCSymbol *S, int64_t O) :
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Reloc(R), Sym(S), Offset(O) {}
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ELFRelocationEntry Reloc;
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const MCSymbol *Sym;
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int64_t Offset;
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};
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typedef std::list<RelEntry> RelLs;
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typedef RelLs::iterator RelLsIter;
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class MipsELFObjectWriter : public MCELFObjectTargetWriter {
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public:
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MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI, bool _isN64);
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virtual ~MipsELFObjectWriter();
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virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
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bool IsPCRel, bool IsRelocWithSymbol,
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int64_t Addend) const;
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virtual unsigned getEFlags() const;
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virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F,
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const MCFixup &Fixup,
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bool IsPCRel) const;
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virtual void sortRelocs(const MCAssembler &Asm,
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std::vector<ELFRelocationEntry> &Relocs);
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};
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}
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MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI,
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bool _isN64)
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: MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS,
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/*HasRelocationAddend*/ false,
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/*IsN64*/ _isN64) {}
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MipsELFObjectWriter::~MipsELFObjectWriter() {}
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// FIXME: get the real EABI Version from the Subtarget class.
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unsigned MipsELFObjectWriter::getEFlags() const {
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// FIXME: We can't tell if we are PIC (dynamic) or CPIC (static)
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unsigned Flag = ELF::EF_MIPS_NOREORDER;
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if (is64Bit())
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Flag |= ELF::EF_MIPS_ARCH_64R2;
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else
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Flag |= ELF::EF_MIPS_ARCH_32R2;
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return Flag;
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}
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const MCSymbol *MipsELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F,
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const MCFixup &Fixup,
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bool IsPCRel) const {
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assert(Target.getSymA() && "SymA cannot be 0.");
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const MCSymbol &Sym = Target.getSymA()->getSymbol().AliasedSymbol();
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if (Sym.getSection().getKind().isMergeableCString() ||
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Sym.getSection().getKind().isMergeableConst())
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return &Sym;
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return NULL;
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}
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unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel,
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bool IsRelocWithSymbol,
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int64_t Addend) const {
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// determine the type of the relocation
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unsigned Type = (unsigned)ELF::R_MIPS_NONE;
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unsigned Kind = (unsigned)Fixup.getKind();
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switch (Kind) {
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default:
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llvm_unreachable("invalid fixup kind!");
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case FK_Data_4:
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Type = ELF::R_MIPS_32;
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break;
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case FK_GPRel_4:
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Type = ELF::R_MIPS_GPREL32;
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break;
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case Mips::fixup_Mips_GPREL16:
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Type = ELF::R_MIPS_GPREL16;
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break;
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case Mips::fixup_Mips_26:
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Type = ELF::R_MIPS_26;
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break;
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case Mips::fixup_Mips_CALL16:
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Type = ELF::R_MIPS_CALL16;
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break;
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case Mips::fixup_Mips_GOT_Global:
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case Mips::fixup_Mips_GOT_Local:
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Type = ELF::R_MIPS_GOT16;
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break;
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case Mips::fixup_Mips_HI16:
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Type = ELF::R_MIPS_HI16;
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break;
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case Mips::fixup_Mips_LO16:
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Type = ELF::R_MIPS_LO16;
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break;
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case Mips::fixup_Mips_TLSGD:
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Type = ELF::R_MIPS_TLS_GD;
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break;
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case Mips::fixup_Mips_GOTTPREL:
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Type = ELF::R_MIPS_TLS_GOTTPREL;
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break;
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case Mips::fixup_Mips_TPREL_HI:
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Type = ELF::R_MIPS_TLS_TPREL_HI16;
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break;
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case Mips::fixup_Mips_TPREL_LO:
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Type = ELF::R_MIPS_TLS_TPREL_LO16;
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break;
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case Mips::fixup_Mips_TLSLDM:
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Type = ELF::R_MIPS_TLS_LDM;
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break;
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case Mips::fixup_Mips_DTPREL_HI:
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Type = ELF::R_MIPS_TLS_DTPREL_HI16;
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break;
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case Mips::fixup_Mips_DTPREL_LO:
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Type = ELF::R_MIPS_TLS_DTPREL_LO16;
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break;
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case Mips::fixup_Mips_Branch_PCRel:
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case Mips::fixup_Mips_PC16:
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Type = ELF::R_MIPS_PC16;
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break;
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case Mips::fixup_Mips_GOT_PAGE:
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Type = ELF::R_MIPS_GOT_PAGE;
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break;
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case Mips::fixup_Mips_GOT_OFST:
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Type = ELF::R_MIPS_GOT_OFST;
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break;
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case Mips::fixup_Mips_GOT_DISP:
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Type = ELF::R_MIPS_GOT_DISP;
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break;
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case Mips::fixup_Mips_GPOFF_HI:
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Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
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Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
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Type = setRType3((unsigned)ELF::R_MIPS_HI16, Type);
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break;
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case Mips::fixup_Mips_GPOFF_LO:
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Type = setRType((unsigned)ELF::R_MIPS_GPREL16, Type);
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Type = setRType2((unsigned)ELF::R_MIPS_SUB, Type);
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Type = setRType3((unsigned)ELF::R_MIPS_LO16, Type);
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break;
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}
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return Type;
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}
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// Return true if R is either a GOT16 against a local symbol or HI16.
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static bool NeedsMatchingLo(const MCAssembler &Asm, const RelEntry &R) {
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if (!R.Sym)
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return false;
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MCSymbolData &SD = Asm.getSymbolData(R.Sym->AliasedSymbol());
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return ((R.Reloc.Type == ELF::R_MIPS_GOT16) && !SD.isExternal()) ||
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(R.Reloc.Type == ELF::R_MIPS_HI16);
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}
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static bool HasMatchingLo(const MCAssembler &Asm, RelLsIter I, RelLsIter Last) {
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if (I == Last)
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return false;
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RelLsIter Hi = I++;
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return (I->Reloc.Type == ELF::R_MIPS_LO16) && (Hi->Sym == I->Sym) &&
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(Hi->Offset == I->Offset);
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}
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static bool HasSameSymbol(const RelEntry &R0, const RelEntry &R1) {
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return R0.Sym == R1.Sym;
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}
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static int CompareOffset(const RelEntry &R0, const RelEntry &R1) {
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return (R0.Offset > R1.Offset) ? 1 : ((R0.Offset == R1.Offset) ? 0 : -1);
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}
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void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
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std::vector<ELFRelocationEntry> &Relocs) {
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// Call the default function first. Relocations are sorted in descending
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// order of r_offset.
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MCELFObjectTargetWriter::sortRelocs(Asm, Relocs);
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RelLs RelocLs;
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std::vector<RelLsIter> Unmatched;
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// Fill RelocLs. Traverse Relocs backwards so that relocations in RelocLs
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// are in ascending order of r_offset.
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for (std::vector<ELFRelocationEntry>::reverse_iterator R = Relocs.rbegin();
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R != Relocs.rend(); ++R) {
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std::pair<const MCSymbolRefExpr*, int64_t> P =
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MipsGetSymAndOffset(*R->Fixup);
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RelocLs.push_back(RelEntry(*R, P.first ? &P.first->getSymbol() : 0,
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P.second));
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}
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// Get list of unmatched HI16 and GOT16.
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for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
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if (NeedsMatchingLo(Asm, *R) && !HasMatchingLo(Asm, R, --RelocLs.end()))
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Unmatched.push_back(R);
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// Insert unmatched HI16 and GOT16 immediately before their matching LO16.
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for (std::vector<RelLsIter>::iterator U = Unmatched.begin();
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U != Unmatched.end(); ++U) {
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RelLsIter LoPos = RelocLs.end(), HiPos = *U;
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bool MatchedLo = false;
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for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) {
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if ((R->Reloc.Type == ELF::R_MIPS_LO16) && HasSameSymbol(*HiPos, *R) &&
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(CompareOffset(*R, *HiPos) >= 0) &&
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((LoPos == RelocLs.end()) || ((CompareOffset(*R, *LoPos) < 0)) ||
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(!MatchedLo && !CompareOffset(*R, *LoPos))))
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LoPos = R;
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MatchedLo = NeedsMatchingLo(Asm, *R) &&
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HasMatchingLo(Asm, R, --RelocLs.end());
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}
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// If a matching LoPos was found, move HiPos and insert it before LoPos.
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// Make the offsets of HiPos and LoPos match.
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if (LoPos != RelocLs.end()) {
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HiPos->Offset = LoPos->Offset;
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RelocLs.insert(LoPos, *HiPos);
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RelocLs.erase(HiPos);
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}
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}
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// Put the sorted list back in reverse order.
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assert(Relocs.size() == RelocLs.size());
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unsigned I = RelocLs.size();
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for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
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Relocs[--I] = R->Reloc;
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}
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MCObjectWriter *llvm::createMipsELFObjectWriter(raw_ostream &OS,
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uint8_t OSABI,
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bool IsLittleEndian,
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bool Is64Bit) {
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MCELFObjectTargetWriter *MOTW = new MipsELFObjectWriter(Is64Bit, OSABI,
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(Is64Bit) ? true : false);
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return createELFObjectWriter(MOTW, OS, IsLittleEndian);
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}
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