aboutsummaryrefslogtreecommitdiff
path: root/lib/MC/ELFObjectWriter.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/MC/ELFObjectWriter.cpp')
-rw-r--r--lib/MC/ELFObjectWriter.cpp86
1 files changed, 41 insertions, 45 deletions
diff --git a/lib/MC/ELFObjectWriter.cpp b/lib/MC/ELFObjectWriter.cpp
index 2c68723a12f8..6f160e491cea 100644
--- a/lib/MC/ELFObjectWriter.cpp
+++ b/lib/MC/ELFObjectWriter.cpp
@@ -36,6 +36,7 @@
#include "llvm/MC/MCSymbolELF.h"
#include "llvm/MC/MCValue.h"
#include "llvm/MC/StringTableBuilder.h"
+#include "llvm/Support/Alignment.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compression.h"
@@ -336,7 +337,7 @@ public:
} // end anonymous namespace
void ELFWriter::align(unsigned Alignment) {
- uint64_t Padding = OffsetToAlignment(W.OS.tell(), Alignment);
+ uint64_t Padding = offsetToAlignment(W.OS.tell(), Align(Alignment));
W.OS.write_zeros(Padding);
}
@@ -511,6 +512,19 @@ static uint8_t mergeTypeForSet(uint8_t origType, uint8_t newType) {
return Type;
}
+static bool isIFunc(const MCSymbolELF *Symbol) {
+ while (Symbol->getType() != ELF::STT_GNU_IFUNC) {
+ const MCSymbolRefExpr *Value;
+ if (!Symbol->isVariable() ||
+ !(Value = dyn_cast<MCSymbolRefExpr>(Symbol->getVariableValue())) ||
+ Value->getKind() != MCSymbolRefExpr::VK_None ||
+ mergeTypeForSet(Symbol->getType(), ELF::STT_GNU_IFUNC) != ELF::STT_GNU_IFUNC)
+ return false;
+ Symbol = &cast<MCSymbolELF>(Value->getSymbol());
+ }
+ return true;
+}
+
void ELFWriter::writeSymbol(SymbolTableWriter &Writer, uint32_t StringIndex,
ELFSymbolData &MSD, const MCAsmLayout &Layout) {
const auto &Symbol = cast<MCSymbolELF>(*MSD.Symbol);
@@ -524,6 +538,8 @@ void ELFWriter::writeSymbol(SymbolTableWriter &Writer, uint32_t StringIndex,
// Binding and Type share the same byte as upper and lower nibbles
uint8_t Binding = Symbol.getBinding();
uint8_t Type = Symbol.getType();
+ if (isIFunc(&Symbol))
+ Type = ELF::STT_GNU_IFUNC;
if (Base) {
Type = mergeTypeForSet(Type, Base->getType());
}
@@ -622,7 +638,7 @@ void ELFWriter::computeSymbolTable(
unsigned EntrySize = is64Bit() ? ELF::SYMENTRY_SIZE64 : ELF::SYMENTRY_SIZE32;
MCSectionELF *SymtabSection =
Ctx.getELFSection(".symtab", ELF::SHT_SYMTAB, 0, EntrySize, "");
- SymtabSection->setAlignment(is64Bit() ? 8 : 4);
+ SymtabSection->setAlignment(is64Bit() ? Align(8) : Align(4));
SymbolTableIndex = addToSectionTable(SymtabSection);
align(SymtabSection->getAlignment());
@@ -720,7 +736,7 @@ void ELFWriter::computeSymbolTable(
MCSectionELF *SymtabShndxSection =
Ctx.getELFSection(".symtab_shndx", ELF::SHT_SYMTAB_SHNDX, 0, 4, "");
SymtabShndxSectionIndex = addToSectionTable(SymtabShndxSection);
- SymtabShndxSection->setAlignment(4);
+ SymtabShndxSection->setAlignment(Align(4));
}
ArrayRef<std::string> FileNames = Asm.getFileNames();
@@ -808,7 +824,7 @@ MCSectionELF *ELFWriter::createRelocationSection(MCContext &Ctx,
MCSectionELF *RelaSection = Ctx.createELFRelSection(
RelaSectionName, hasRelocationAddend() ? ELF::SHT_RELA : ELF::SHT_REL,
Flags, EntrySize, Sec.getGroup(), &Sec);
- RelaSection->setAlignment(is64Bit() ? 8 : 4);
+ RelaSection->setAlignment(is64Bit() ? Align(8) : Align(4));
return RelaSection;
}
@@ -895,7 +911,7 @@ void ELFWriter::writeSectionData(const MCAssembler &Asm, MCSection &Sec,
Section.setFlags(Section.getFlags() | ELF::SHF_COMPRESSED);
// Alignment field should reflect the requirements of
// the compressed section header.
- Section.setAlignment(is64Bit() ? 8 : 4);
+ Section.setAlignment(is64Bit() ? Align(8) : Align(4));
} else {
// Add "z" prefix to section name. This is zlib-gnu style.
MC.renameELFSection(&Section, (".z" + SectionName.drop_front(1)).str());
@@ -1119,7 +1135,7 @@ uint64_t ELFWriter::writeObject(MCAssembler &Asm, const MCAsmLayout &Layout) {
if (!GroupIdx) {
MCSectionELF *Group = Ctx.createELFGroupSection(SignatureSymbol);
GroupIdx = addToSectionTable(Group);
- Group->setAlignment(4);
+ Group->setAlignment(Align(4));
Groups.push_back(Group);
}
std::vector<const MCSectionELF *> &Members =
@@ -1437,22 +1453,7 @@ void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
MCContext &Ctx = Asm.getContext();
if (const MCSymbolRefExpr *RefB = Target.getSymB()) {
- // Let A, B and C being the components of Target and R be the location of
- // the fixup. If the fixup is not pcrel, we want to compute (A - B + C).
- // If it is pcrel, we want to compute (A - B + C - R).
-
- // In general, ELF has no relocations for -B. It can only represent (A + C)
- // or (A + C - R). If B = R + K and the relocation is not pcrel, we can
- // replace B to implement it: (A - R - K + C)
- if (IsPCRel) {
- Ctx.reportError(
- Fixup.getLoc(),
- "No relocation available to represent this relative expression");
- return;
- }
-
const auto &SymB = cast<MCSymbolELF>(RefB->getSymbol());
-
if (SymB.isUndefined()) {
Ctx.reportError(Fixup.getLoc(),
Twine("symbol '") + SymB.getName() +
@@ -1468,10 +1469,9 @@ void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
return;
}
- uint64_t SymBOffset = Layout.getSymbolOffset(SymB);
- uint64_t K = SymBOffset - FixupOffset;
+ assert(!IsPCRel && "should have been folded");
IsPCRel = true;
- C -= K;
+ C += FixupOffset - Layout.getSymbolOffset(SymB);
}
// We either rejected the fixup or folded B into C at this point.
@@ -1489,38 +1489,35 @@ void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
}
}
- unsigned Type = TargetObjectWriter->getRelocType(Ctx, Target, Fixup, IsPCRel);
- uint64_t OriginalC = C;
- bool RelocateWithSymbol = shouldRelocateWithSymbol(Asm, RefA, SymA, C, Type);
- if (!RelocateWithSymbol && SymA && !SymA->isUndefined())
- C += Layout.getSymbolOffset(*SymA);
-
- uint64_t Addend = 0;
- if (hasRelocationAddend()) {
- Addend = C;
- C = 0;
- }
-
- FixedValue = C;
-
const MCSectionELF *SecA = (SymA && SymA->isInSection())
? cast<MCSectionELF>(&SymA->getSection())
: nullptr;
if (!checkRelocation(Ctx, Fixup.getLoc(), &FixupSection, SecA))
return;
+ unsigned Type = TargetObjectWriter->getRelocType(Ctx, Target, Fixup, IsPCRel);
+ bool RelocateWithSymbol = shouldRelocateWithSymbol(Asm, RefA, SymA, C, Type);
+ uint64_t Addend = 0;
+
+ FixedValue = !RelocateWithSymbol && SymA && !SymA->isUndefined()
+ ? C + Layout.getSymbolOffset(*SymA)
+ : C;
+ if (hasRelocationAddend()) {
+ Addend = FixedValue;
+ FixedValue = 0;
+ }
+
if (!RelocateWithSymbol) {
const auto *SectionSymbol =
SecA ? cast<MCSymbolELF>(SecA->getBeginSymbol()) : nullptr;
if (SectionSymbol)
SectionSymbol->setUsedInReloc();
- ELFRelocationEntry Rec(FixupOffset, SectionSymbol, Type, Addend, SymA,
- OriginalC);
+ ELFRelocationEntry Rec(FixupOffset, SectionSymbol, Type, Addend, SymA, C);
Relocations[&FixupSection].push_back(Rec);
return;
}
- const auto *RenamedSymA = SymA;
+ const MCSymbolELF *RenamedSymA = SymA;
if (SymA) {
if (const MCSymbolELF *R = Renames.lookup(SymA))
RenamedSymA = R;
@@ -1530,8 +1527,7 @@ void ELFObjectWriter::recordRelocation(MCAssembler &Asm,
else
RenamedSymA->setUsedInReloc();
}
- ELFRelocationEntry Rec(FixupOffset, RenamedSymA, Type, Addend, SymA,
- OriginalC);
+ ELFRelocationEntry Rec(FixupOffset, RenamedSymA, Type, Addend, SymA, C);
Relocations[&FixupSection].push_back(Rec);
}
@@ -1551,7 +1547,7 @@ bool ELFObjectWriter::isSymbolRefDifferenceFullyResolvedImpl(
std::unique_ptr<MCObjectWriter>
llvm::createELFObjectWriter(std::unique_ptr<MCELFObjectTargetWriter> MOTW,
raw_pwrite_stream &OS, bool IsLittleEndian) {
- return llvm::make_unique<ELFSingleObjectWriter>(std::move(MOTW), OS,
+ return std::make_unique<ELFSingleObjectWriter>(std::move(MOTW), OS,
IsLittleEndian);
}
@@ -1559,6 +1555,6 @@ std::unique_ptr<MCObjectWriter>
llvm::createELFDwoObjectWriter(std::unique_ptr<MCELFObjectTargetWriter> MOTW,
raw_pwrite_stream &OS, raw_pwrite_stream &DwoOS,
bool IsLittleEndian) {
- return llvm::make_unique<ELFDwoObjectWriter>(std::move(MOTW), OS, DwoOS,
+ return std::make_unique<ELFDwoObjectWriter>(std::move(MOTW), OS, DwoOS,
IsLittleEndian);
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-27 04:22:40 +0000