Vendor import of llvm trunk r154661:

http://llvm.org/svn/llvm-project/llvm/trunk@r154661

1 files changed, 249 insertions, 0 deletions

diff --git a/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp b/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
new file mode 100644
index 0000000..2091bec
--- /dev/null
+++ b/lib/Target/Mips/MCTargetDesc/MipsELFObjectWriter.cpp
@@ -0,0 +1,249 @@
+//===-- MipsELFObjectWriter.cpp - Mips 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/MipsBaseInfo.h"
+#include "MCTargetDesc/MipsFixupKinds.h"
+#include "MCTargetDesc/MipsMCTargetDesc.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCSection.h"
+#include "llvm/MC/MCValue.h"
+#include "llvm/Support/ErrorHandling.h"
+#include <list>
+
+using namespace llvm;
+
+namespace {
+  struct RelEntry {
+    RelEntry(const ELFRelocationEntry &R, const MCSymbol *S, int64_t O) :
+      Reloc(R), Sym(S), Offset(O) {}
+    ELFRelocationEntry Reloc;
+    const MCSymbol *Sym;
+    int64_t Offset;
+  };
+
+  typedef std::list<RelEntry> RelLs;
+  typedef RelLs::iterator RelLsIter;
+
+  class MipsELFObjectWriter : public MCELFObjectTargetWriter {
+  public:
+    MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI);
+
+    virtual ~MipsELFObjectWriter();
+
+    virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
+                                  bool IsPCRel, bool IsRelocWithSymbol,
+                                  int64_t Addend) const;
+    virtual unsigned getEFlags() const;
+    virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
+                                           const MCValue &Target,
+                                           const MCFragment &F,
+                                           const MCFixup &Fixup,
+                                           bool IsPCRel) const;
+    virtual void sortRelocs(const MCAssembler &Asm,
+                            std::vector<ELFRelocationEntry> &Relocs);
+  };
+}
+
+MipsELFObjectWriter::MipsELFObjectWriter(bool _is64Bit, uint8_t OSABI)
+  : MCELFObjectTargetWriter(_is64Bit, OSABI, ELF::EM_MIPS,
+                            /*HasRelocationAddend*/ false) {}
+
+MipsELFObjectWriter::~MipsELFObjectWriter() {}
+
+// FIXME: get the real EABI Version from the Subtarget class.
+unsigned MipsELFObjectWriter::getEFlags() const {
+
+  // FIXME: We can't tell if we are PIC (dynamic) or CPIC (static)
+  unsigned Flag = ELF::EF_MIPS_NOREORDER;
+
+  if (is64Bit())
+    Flag |= ELF::EF_MIPS_ARCH_64R2;
+  else
+    Flag |= ELF::EF_MIPS_ARCH_32R2;
+  return Flag;
+}
+
+const MCSymbol *MipsELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
+                                                    const MCValue &Target,
+                                                    const MCFragment &F,
+                                                    const MCFixup &Fixup,
+                                                    bool IsPCRel) const {
+  assert(Target.getSymA() && "SymA cannot be 0.");
+  const MCSymbol &Sym = Target.getSymA()->getSymbol().AliasedSymbol();
+
+  if (Sym.getSection().getKind().isMergeableCString() ||
+      Sym.getSection().getKind().isMergeableConst())
+    return &Sym;
+
+  return NULL;
+}
+
+unsigned MipsELFObjectWriter::GetRelocType(const MCValue &Target,
+                                           const MCFixup &Fixup,
+                                           bool IsPCRel,
+                                           bool IsRelocWithSymbol,
+                                           int64_t Addend) const {
+  // determine the type of the relocation
+  unsigned Type = (unsigned)ELF::R_MIPS_NONE;
+  unsigned Kind = (unsigned)Fixup.getKind();
+
+  switch (Kind) {
+  default:
+    llvm_unreachable("invalid fixup kind!");
+  case FK_Data_4:
+    Type = ELF::R_MIPS_32;
+    break;
+  case FK_GPRel_4:
+    Type = ELF::R_MIPS_GPREL32;
+    break;
+  case Mips::fixup_Mips_GPREL16:
+    Type = ELF::R_MIPS_GPREL16;
+    break;
+  case Mips::fixup_Mips_26:
+    Type = ELF::R_MIPS_26;
+    break;
+  case Mips::fixup_Mips_CALL16:
+    Type = ELF::R_MIPS_CALL16;
+    break;
+  case Mips::fixup_Mips_GOT_Global:
+  case Mips::fixup_Mips_GOT_Local:
+    Type = ELF::R_MIPS_GOT16;
+    break;
+  case Mips::fixup_Mips_HI16:
+    Type = ELF::R_MIPS_HI16;
+    break;
+  case Mips::fixup_Mips_LO16:
+    Type = ELF::R_MIPS_LO16;
+    break;
+  case Mips::fixup_Mips_TLSGD:
+    Type = ELF::R_MIPS_TLS_GD;
+    break;
+  case Mips::fixup_Mips_GOTTPREL:
+    Type = ELF::R_MIPS_TLS_GOTTPREL;
+    break;
+  case Mips::fixup_Mips_TPREL_HI:
+    Type = ELF::R_MIPS_TLS_TPREL_HI16;
+    break;
+  case Mips::fixup_Mips_TPREL_LO:
+    Type = ELF::R_MIPS_TLS_TPREL_LO16;
+    break;
+  case Mips::fixup_Mips_TLSLDM:
+    Type = ELF::R_MIPS_TLS_LDM;
+    break;
+  case Mips::fixup_Mips_DTPREL_HI:
+    Type = ELF::R_MIPS_TLS_DTPREL_HI16;
+    break;
+  case Mips::fixup_Mips_DTPREL_LO:
+    Type = ELF::R_MIPS_TLS_DTPREL_LO16;
+    break;
+  case Mips::fixup_Mips_Branch_PCRel:
+  case Mips::fixup_Mips_PC16:
+    Type = ELF::R_MIPS_PC16;
+    break;
+  }
+
+  return Type;
+}
+
+// Return true if R is either a GOT16 against a local symbol or HI16.
+static bool NeedsMatchingLo(const MCAssembler &Asm, const RelEntry &R) {
+  if (!R.Sym)
+    return false;
+
+  MCSymbolData &SD = Asm.getSymbolData(R.Sym->AliasedSymbol());
+
+  return ((R.Reloc.Type == ELF::R_MIPS_GOT16) && !SD.isExternal()) ||
+    (R.Reloc.Type == ELF::R_MIPS_HI16);
+}
+
+static bool HasMatchingLo(const MCAssembler &Asm, RelLsIter I, RelLsIter Last) {
+  if (I == Last)
+    return false;
+
+  RelLsIter Hi = I++;
+
+  return (I->Reloc.Type == ELF::R_MIPS_LO16) && (Hi->Sym == I->Sym) &&
+    (Hi->Offset == I->Offset);
+}
+
+static bool HasSameSymbol(const RelEntry &R0, const RelEntry &R1) {
+  return R0.Sym == R1.Sym;
+}
+
+static int CompareOffset(const RelEntry &R0, const RelEntry &R1) {
+  return (R0.Offset > R1.Offset) ? 1 : ((R0.Offset == R1.Offset) ? 0 : -1);
+}
+
+void MipsELFObjectWriter::sortRelocs(const MCAssembler &Asm,
+                                     std::vector<ELFRelocationEntry> &Relocs) {
+  // Call the defualt function first. Relocations are sorted in descending
+  // order of r_offset.
+  MCELFObjectTargetWriter::sortRelocs(Asm, Relocs);
+  
+  RelLs RelocLs;
+  std::vector<RelLsIter> Unmatched;
+
+  // Fill RelocLs. Traverse Relocs backwards so that relocations in RelocLs
+  // are in ascending order of r_offset.
+  for (std::vector<ELFRelocationEntry>::reverse_iterator R = Relocs.rbegin();
+       R != Relocs.rend(); ++R) {
+     std::pair<const MCSymbolRefExpr*, int64_t> P =
+       MipsGetSymAndOffset(*R->Fixup);
+     RelocLs.push_back(RelEntry(*R, P.first ? &P.first->getSymbol() : 0,
+                                P.second));
+  }
+
+  // Get list of unmatched HI16 and GOT16.
+  for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
+    if (NeedsMatchingLo(Asm, *R) && !HasMatchingLo(Asm, R, --RelocLs.end()))
+      Unmatched.push_back(R);
+
+  // Insert unmatched HI16 and GOT16 immediately before their matching LO16.
+  for (std::vector<RelLsIter>::iterator U = Unmatched.begin();
+       U != Unmatched.end(); ++U) {
+    RelLsIter LoPos = RelocLs.end(), HiPos = *U;
+    bool MatchedLo = false;
+
+    for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R) {
+      if ((R->Reloc.Type == ELF::R_MIPS_LO16) && HasSameSymbol(*HiPos, *R) &&
+          (CompareOffset(*R, *HiPos) >= 0) &&
+          ((LoPos == RelocLs.end()) || ((CompareOffset(*R, *LoPos) < 0)) ||
+           (!MatchedLo && !CompareOffset(*R, *LoPos))))
+        LoPos = R;
+
+      MatchedLo = NeedsMatchingLo(Asm, *R) &&
+        HasMatchingLo(Asm, R, --RelocLs.end());
+    }
+
+    // If a matching LoPos was found, move HiPos and insert it before LoPos.
+    // Make the offsets of HiPos and LoPos match.
+    if (LoPos != RelocLs.end()) {
+      HiPos->Offset = LoPos->Offset;
+      RelocLs.insert(LoPos, *HiPos);
+      RelocLs.erase(HiPos);
+    }
+  }
+
+  // Put the sorted list back in reverse order.
+  assert(Relocs.size() == RelocLs.size());
+  unsigned I = RelocLs.size();
+
+  for (RelLsIter R = RelocLs.begin(); R != RelocLs.end(); ++R)
+    Relocs[--I] = R->Reloc;
+}
+
+MCObjectWriter *llvm::createMipsELFObjectWriter(raw_ostream &OS,
+                                                uint8_t OSABI,
+                                                bool IsLittleEndian,
+                                                bool Is64Bit) {
+  MCELFObjectTargetWriter *MOTW = new MipsELFObjectWriter(Is64Bit, OSABI);
+  return createELFObjectWriter(MOTW, OS, IsLittleEndian);
+}