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Move the logic to decide with which symbol we produce a relocation (if any) to

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a central location. This also makes us a bit more compatible with gas.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119094 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Rafael Espindola 2010-11-14 23:53:26 +00:00
parent b908258d59
commit 1f52dfe69e
2 changed files with 62 additions and 35 deletions
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71
lib/MC/ELFObjectWriter.cpp
View File

@ -180,6 +180,11 @@ namespace {
unsigned ShstrtabIndex;
const MCSymbol *SymbolToReloc(const MCAssembler &Asm,
const MCValue &Target,
const MCFragment &F) const;
public:
ELFObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool IsLittleEndian,
uint16_t _EMachine, bool _HasRelAddend,
@ -624,36 +629,53 @@ void ELFObjectWriter::WriteSymbolTable(MCDataFragment *SymtabF,
}
}
static bool ShouldRelocOnSymbol(const MCSymbolData &SD,
const MCValue &Target,
const MCFragment &F) {
const MCSymbol &Symbol = SD.getSymbol();
const MCSymbol *ELFObjectWriter::SymbolToReloc(const MCAssembler &Asm,
const MCValue &Target,
const MCFragment &F) const {
const MCSymbol &Symbol = Target.getSymA()->getSymbol();
const MCSymbol &ASymbol = AliasedSymbol(Symbol);
const MCSymbol *RenamedP = Renames.lookup(&Symbol);
if (!RenamedP) {
if (Target.getSymA()->getKind() == MCSymbolRefExpr::VK_None ||
Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
RenamedP = &ASymbol;
else
RenamedP = &Symbol;
}
const MCSymbol &Renamed = *RenamedP;
MCSymbolData &SD = Asm.getSymbolData(Symbol);
if (Symbol.isUndefined())
return true;
return &Renamed;
if (SD.isExternal())
return &Renamed;
const MCSectionELF &Section =
static_cast<const MCSectionELF&>(Symbol.getSection());
if (SD.isExternal())
return true;
if (Section.getKind().isBSS())
return NULL;
MCSymbolRefExpr::VariantKind Kind = Target.getSymA()->getKind();
const MCSectionELF &Sec2 =
static_cast<const MCSectionELF&>(F.getParent()->getSection());
if (Section.getKind().isBSS())
return false;
if (&Sec2 != &Section &&
(Kind == MCSymbolRefExpr::VK_PLT ||
Kind == MCSymbolRefExpr::VK_GOTPCREL ||
Kind == MCSymbolRefExpr::VK_GOTOFF))
return true;
return &Renamed;
if (Section.getFlags() & MCSectionELF::SHF_MERGE)
return Target.getConstant() != 0;
if (Section.getFlags() & MCSectionELF::SHF_MERGE) {
if (Target.getConstant() != 0)
return &Renamed;
return NULL;
}
return false;
return NULL;
}
// FIXME: this is currently X86/X86_64 only
@ -667,17 +689,10 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
int Index = 0;
int64_t Value = Target.getConstant();
const MCSymbol &Symbol = Target.getSymA()->getSymbol();
const MCSymbol &ASymbol = AliasedSymbol(Symbol);
const MCSymbol *RenamedP = Renames.lookup(&Symbol);
if (!RenamedP)
RenamedP = &ASymbol;
const MCSymbol &Renamed = *RenamedP;
const MCSymbol *RelocSymbol = SymbolToReloc(Asm, Target, *Fragment);
bool IsPCRel = isFixupKindX86PCRel(Fixup.getKind());
if (!Target.isAbsolute()) {
MCSymbolData &SD = Asm.getSymbolData(Symbol);
MCFragment *F = SD.getFragment();
if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
const MCSymbol &SymbolB = RefB->getSymbol();
MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
@ -692,8 +707,10 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
Value += b - a;
}
bool RelocOnSymbol = ShouldRelocOnSymbol(SD, Target, *Fragment);
if (!RelocOnSymbol) {
if (!RelocSymbol) {
MCSymbolData &SD = Asm.getSymbolData(Symbol);
MCFragment *F = SD.getFragment();
Index = F->getParent()->getOrdinal();
MCSectionData *FSD = F->getParent();
@ -701,9 +718,9 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
Value += Layout.getSymbolAddress(&SD) - Layout.getSectionAddress(FSD);
} else {
if (Asm.getSymbolData(Symbol).getFlags() & ELF_Other_Weakref)
WeakrefUsedInReloc.insert(&Renamed);
WeakrefUsedInReloc.insert(RelocSymbol);
else
UsedInReloc.insert(&Renamed);
UsedInReloc.insert(RelocSymbol);
Index = -1;
}
Addend = Value;
@ -851,7 +868,7 @@ void ELFObjectWriter::RecordRelocation(const MCAssembler &Asm,
ERE.Index = Index;
ERE.Type = Type;
ERE.Symbol = &Renamed;
ERE.Symbol = RelocSymbol;
ERE.r_offset = Layout.getFragmentOffset(Fragment) + Fixup.getOffset();

26
test/MC/ELF/alias-reloc.s
View File

@ -1,16 +1,26 @@
// RUN: llvm-mc -filetype=obj -triple x86_64-pc-linux-gnu %s -o - | elf-dump | FileCheck %s
// Test that this produces a R_X86_64_PLT32. We produce a relocation with foo
// and gas with bar, but both should be OK as long as the type is correct.
// Test that this produces a R_X86_64_PLT32 with bar.
.globl foo
foo:
bar = foo
.section zed, "", @progbits
call bar@PLT
// CHECK: # Relocation 0
// CHECK-NEXT: (('r_offset',
// CHECK-NEXT: ('r_sym',
// CHECK-NEXT: ('r_type', 0x00000004)
// CHECK-NEXT: ('r_addend',
// CHECK: # Symbol 0x00000001
// CHECK-NEXT: (('st_name', 0x00000005) # 'bar'
// CHECK-NEXT: ('st_bind', 0x00000000)
// CHECK-NEXT: ('st_type', 0x00000000)
// CHECK-NEXT: ('st_other', 0x00000000)
// CHECK-NEXT: ('st_shndx', 0x00000001)
// CHECK-NEXT: ('st_value', 0x00000000)
// CHECK-NEXT: ('st_size', 0x00000000)
// CHECK-NEXT: ),
// CHECK: # Relocation 0x00000000
// CHECK-NEXT: (('r_offset', 0x00000001)
// CHECK-NEXT: ('r_sym', 0x00000001)
// CHECK-NEXT: ('r_type', 0x00000004)
// CHECK-NEXT: ('r_addend', 0xfffffffc)
// CHECK-NEXT: ),
// CHECK-NEXT: ])