#include "llvm/Support/MachO.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Support/Debug.h"
+#include "llvm/Target/TargetRegistry.h"
#include "llvm/Target/TargetAsmBackend.h"
// FIXME: Gross.
static bool isVirtualSection(const MCSection &Section) {
// FIXME: Lame.
const MCSectionMachO &SMO = static_cast<const MCSectionMachO&>(Section);
- unsigned Type = SMO.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- return (Type == MCSectionMachO::S_ZEROFILL);
+ return (SMO.getType() == MCSectionMachO::S_ZEROFILL);
}
static unsigned getFixupKindLog2Size(unsigned Kind) {
Header_Magic64 = 0xFEEDFACF
};
- static const unsigned Header32Size = 28;
- static const unsigned Header64Size = 32;
- static const unsigned SegmentLoadCommand32Size = 56;
- static const unsigned Section32Size = 68;
- static const unsigned SymtabLoadCommandSize = 24;
- static const unsigned DysymtabLoadCommandSize = 80;
- static const unsigned Nlist32Size = 12;
- static const unsigned RelocationInfoSize = 8;
+ enum {
+ Header32Size = 28,
+ Header64Size = 32,
+ SegmentLoadCommand32Size = 56,
+ SegmentLoadCommand64Size = 72,
+ Section32Size = 68,
+ Section64Size = 80,
+ SymtabLoadCommandSize = 24,
+ DysymtabLoadCommandSize = 80,
+ Nlist32Size = 12,
+ Nlist64Size = 16,
+ RelocationInfoSize = 8
+ };
enum HeaderFileType {
HFT_Object = 0x1
enum LoadCommandType {
LCT_Segment = 0x1,
LCT_Symtab = 0x2,
- LCT_Dysymtab = 0xb
+ LCT_Dysymtab = 0xb,
+ LCT_Segment64 = 0x19
};
// See <mach-o/nlist.h>.
};
raw_ostream &OS;
- bool IsLSB;
+ unsigned Is64Bit : 1;
+ unsigned IsLSB : 1;
+
+ /// @name Relocation Data
+ /// @{
+
+ struct MachRelocationEntry {
+ uint32_t Word0;
+ uint32_t Word1;
+ };
+
+ llvm::DenseMap<const MCSectionData*,
+ std::vector<MachRelocationEntry> > Relocations;
+
+ /// @}
+ /// @name Symbol Table Data
+
+ SmallString<256> StringTable;
+ std::vector<MachSymbolData> LocalSymbolData;
+ std::vector<MachSymbolData> ExternalSymbolData;
+ std::vector<MachSymbolData> UndefinedSymbolData;
+
+ /// @}
public:
- MachObjectWriter(raw_ostream &_OS, bool _IsLSB = true)
- : OS(_OS), IsLSB(_IsLSB) {
+ MachObjectWriter(raw_ostream &_OS, bool _Is64Bit, bool _IsLSB = true)
+ : OS(_OS), Is64Bit(_Is64Bit), IsLSB(_IsLSB) {
}
/// @name Helper Methods
/// @}
- void WriteHeader32(unsigned NumLoadCommands, unsigned LoadCommandsSize,
- bool SubsectionsViaSymbols) {
+ void WriteHeader(unsigned NumLoadCommands, unsigned LoadCommandsSize,
+ bool SubsectionsViaSymbols) {
uint32_t Flags = 0;
if (SubsectionsViaSymbols)
Flags |= HF_SubsectionsViaSymbols;
- // struct mach_header (28 bytes)
+ // struct mach_header (28 bytes) or
+ // struct mach_header_64 (32 bytes)
uint64_t Start = OS.tell();
(void) Start;
- Write32(Header_Magic32);
+ Write32(Is64Bit ? Header_Magic64 : Header_Magic32);
// FIXME: Support cputype.
- Write32(MachO::CPUTypeI386);
+ Write32(Is64Bit ? MachO::CPUTypeX86_64 : MachO::CPUTypeI386);
// FIXME: Support cpusubtype.
Write32(MachO::CPUSubType_I386_ALL);
Write32(HFT_Object);
// segment.
Write32(LoadCommandsSize);
Write32(Flags);
+ if (Is64Bit)
+ Write32(0); // reserved
- assert(OS.tell() - Start == Header32Size);
+ assert(OS.tell() - Start == Is64Bit ? Header64Size : Header32Size);
}
- /// WriteSegmentLoadCommand32 - Write a 32-bit segment load command.
+ /// WriteSegmentLoadCommand - Write a segment load command.
///
/// \arg NumSections - The number of sections in this segment.
/// \arg SectionDataSize - The total size of the sections.
- void WriteSegmentLoadCommand32(unsigned NumSections,
- uint64_t VMSize,
- uint64_t SectionDataStartOffset,
- uint64_t SectionDataSize) {
- // struct segment_command (56 bytes)
+ void WriteSegmentLoadCommand(unsigned NumSections,
+ uint64_t VMSize,
+ uint64_t SectionDataStartOffset,
+ uint64_t SectionDataSize) {
+ // struct segment_command (56 bytes) or
+ // struct segment_command_64 (72 bytes)
uint64_t Start = OS.tell();
(void) Start;
- Write32(LCT_Segment);
- Write32(SegmentLoadCommand32Size + NumSections * Section32Size);
+ unsigned SegmentLoadCommandSize = Is64Bit ? SegmentLoadCommand64Size :
+ SegmentLoadCommand32Size;
+ Write32(Is64Bit ? LCT_Segment64 : LCT_Segment);
+ Write32(SegmentLoadCommandSize +
+ NumSections * (Is64Bit ? Section64Size : Section32Size));
WriteString("", 16);
- Write32(0); // vmaddr
- Write32(VMSize); // vmsize
- Write32(SectionDataStartOffset); // file offset
- Write32(SectionDataSize); // file size
+ if (Is64Bit) {
+ Write64(0); // vmaddr
+ Write64(VMSize); // vmsize
+ Write64(SectionDataStartOffset); // file offset
+ Write64(SectionDataSize); // file size
+ } else {
+ Write32(0); // vmaddr
+ Write32(VMSize); // vmsize
+ Write32(SectionDataStartOffset); // file offset
+ Write32(SectionDataSize); // file size
+ }
Write32(0x7); // maxprot
Write32(0x7); // initprot
Write32(NumSections);
Write32(0); // flags
- assert(OS.tell() - Start == SegmentLoadCommand32Size);
+ assert(OS.tell() - Start == SegmentLoadCommandSize);
}
- void WriteSection32(const MCSectionData &SD, uint64_t FileOffset,
- uint64_t RelocationsStart, unsigned NumRelocations) {
+ void WriteSection(const MCSectionData &SD, uint64_t FileOffset,
+ uint64_t RelocationsStart, unsigned NumRelocations) {
// The offset is unused for virtual sections.
if (isVirtualSection(SD.getSection())) {
assert(SD.getFileSize() == 0 && "Invalid file size!");
FileOffset = 0;
}
- // struct section (68 bytes)
+ // struct section (68 bytes) or
+ // struct section_64 (80 bytes)
uint64_t Start = OS.tell();
(void) Start;
static_cast<const MCSectionMachO&>(SD.getSection());
WriteString(Section.getSectionName(), 16);
WriteString(Section.getSegmentName(), 16);
- Write32(SD.getAddress()); // address
- Write32(SD.getSize()); // size
+ if (Is64Bit) {
+ Write64(SD.getAddress()); // address
+ Write64(SD.getSize()); // size
+ } else {
+ Write32(SD.getAddress()); // address
+ Write32(SD.getSize()); // size
+ }
Write32(FileOffset);
unsigned Flags = Section.getTypeAndAttributes();
Write32(Flags);
Write32(0); // reserved1
Write32(Section.getStubSize()); // reserved2
+ if (Is64Bit)
+ Write32(0); // reserved3
- assert(OS.tell() - Start == Section32Size);
+ assert(OS.tell() - Start == Is64Bit ? Section64Size : Section32Size);
}
void WriteSymtabLoadCommand(uint32_t SymbolOffset, uint32_t NumSymbols,
assert(OS.tell() - Start == DysymtabLoadCommandSize);
}
- void WriteNlist32(MachSymbolData &MSD) {
+ void WriteNlist(MachSymbolData &MSD) {
MCSymbolData &Data = *MSD.SymbolData;
const MCSymbol &Symbol = Data.getSymbol();
uint8_t Type = 0;
// The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
// value.
Write16(Flags);
- Write32(Address);
+ if (Is64Bit)
+ Write64(Address);
+ else
+ Write32(Address);
}
- struct MachRelocationEntry {
- uint32_t Word0;
- uint32_t Word1;
- };
- void ComputeScatteredRelocationInfo(MCAssembler &Asm, MCFragment &Fragment,
- MCAsmFixup &Fixup,
- const MCValue &Target,
- std::vector<MachRelocationEntry> &Relocs) {
+ void RecordScatteredRelocation(MCAssembler &Asm, MCFragment &Fragment,
+ const MCAsmFixup &Fixup, MCValue Target,
+ uint64_t &FixedValue) {
uint32_t Address = Fragment.getOffset() + Fixup.Offset;
unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
unsigned Type = RIT_Vanilla;
// See <reloc.h>.
- const MCSymbol *A = Target.getSymA();
+ const MCSymbol *A = &Target.getSymA()->getSymbol();
MCSymbolData *A_SD = &Asm.getSymbolData(*A);
if (!A_SD->getFragment())
uint32_t Value = A_SD->getAddress();
uint32_t Value2 = 0;
- if (const MCSymbol *B = Target.getSymB()) {
- MCSymbolData *B_SD = &Asm.getSymbolData(*B);
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ MCSymbolData *B_SD = &Asm.getSymbolData(B->getSymbol());
if (!B_SD->getFragment())
- llvm_report_error("symbol '" + B->getName() +
+ llvm_report_error("symbol '" + B->getSymbol().getName() +
"' can not be undefined in a subtraction expression");
// Select the appropriate difference relocation type.
Value2 = B_SD->getAddress();
}
- MachRelocationEntry MRE;
- MRE.Word0 = ((Address << 0) |
- (Type << 24) |
- (Log2Size << 28) |
- (IsPCRel << 30) |
- RF_Scattered);
- MRE.Word1 = Value;
- Relocs.push_back(MRE);
-
+ // Relocations are written out in reverse order, so the PAIR comes first.
if (Type == RIT_Difference || Type == RIT_LocalDifference) {
MachRelocationEntry MRE;
MRE.Word0 = ((0 << 0) |
(IsPCRel << 30) |
RF_Scattered);
MRE.Word1 = Value2;
- Relocs.push_back(MRE);
+ Relocations[Fragment.getParent()].push_back(MRE);
}
+
+ MachRelocationEntry MRE;
+ MRE.Word0 = ((Address << 0) |
+ (Type << 24) |
+ (Log2Size << 28) |
+ (IsPCRel << 30) |
+ RF_Scattered);
+ MRE.Word1 = Value;
+ Relocations[Fragment.getParent()].push_back(MRE);
}
- void ComputeRelocationInfo(MCAssembler &Asm, MCDataFragment &Fragment,
- MCAsmFixup &Fixup,
- std::vector<MachRelocationEntry> &Relocs) {
+ void RecordRelocation(MCAssembler &Asm, MCDataFragment &Fragment,
+ const MCAsmFixup &Fixup, MCValue Target,
+ uint64_t &FixedValue) {
unsigned IsPCRel = isFixupKindPCRel(Fixup.Kind);
unsigned Log2Size = getFixupKindLog2Size(Fixup.Kind);
- // FIXME: Share layout object.
- MCAsmLayout Layout(Asm);
-
- // Evaluate the fixup; if the value was resolved, no relocation is needed.
- MCValue Target;
- if (Asm.EvaluateFixup(Layout, Fixup, &Fragment, Target, Fixup.FixedValue))
- return;
-
// If this is a difference or a defined symbol plus an offset, then we need
// a scattered relocation entry.
uint32_t Offset = Target.getConstant();
if (IsPCRel)
Offset += 1 << Log2Size;
if (Target.getSymB() ||
- (Target.getSymA() && !Target.getSymA()->isUndefined() &&
- Offset))
- return ComputeScatteredRelocationInfo(Asm, Fragment, Fixup, Target,
- Relocs);
+ (Target.getSymA() && !Target.getSymA()->getSymbol().isUndefined() &&
+ Offset)) {
+ RecordScatteredRelocation(Asm, Fragment, Fixup, Target, FixedValue);
+ return;
+ }
// See <reloc.h>.
uint32_t Address = Fragment.getOffset() + Fixup.Offset;
Type = RIT_Vanilla;
Value = 0;
} else {
- const MCSymbol *Symbol = Target.getSymA();
+ const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
MCSymbolData *SD = &Asm.getSymbolData(*Symbol);
if (Symbol->isUndefined()) {
(Log2Size << 25) |
(IsExtern << 27) |
(Type << 28));
- Relocs.push_back(MRE);
+ Relocations[Fragment.getParent()].push_back(MRE);
+ }
+
+ void ComputeRelocationInfo(MCAssembler &Asm, MCDataFragment &Fragment,
+ MCAsmFixup &Fixup) {
+ // FIXME: Share layout object.
+ MCAsmLayout Layout(Asm);
+
+ // Evaluate the fixup; if the value was resolved, no relocation is needed.
+ MCValue Target;
+ if (Asm.EvaluateFixup(Layout, Fixup, &Fragment, Target, Fixup.FixedValue))
+ return;
+
+ RecordRelocation(Asm, Fragment, Fixup, Target, Fixup.FixedValue);
}
void BindIndirectSymbols(MCAssembler &Asm) {
const MCSectionMachO &Section =
static_cast<const MCSectionMachO&>(it->SectionData->getSection());
- unsigned Type =
- Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- if (Type != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS)
+ if (Section.getType() != MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS)
continue;
Asm.getOrCreateSymbolData(*it->Symbol);
const MCSectionMachO &Section =
static_cast<const MCSectionMachO&>(it->SectionData->getSection());
- unsigned Type =
- Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- if (Type != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
- Type != MCSectionMachO::S_SYMBOL_STUBS)
+ if (Section.getType() != MCSectionMachO::S_LAZY_SYMBOL_POINTERS &&
+ Section.getType() != MCSectionMachO::S_SYMBOL_STUBS)
continue;
// Set the symbol type to undefined lazy, but only on construction.
ie = Asm.symbol_end(); it != ie; ++it) {
const MCSymbol &Symbol = it->getSymbol();
- // Ignore assembler temporaries.
- if (it->getSymbol().isTemporary())
+ // Ignore non-linker visible symbols.
+ if (!Asm.isSymbolLinkerVisible(it))
continue;
if (!it->isExternal() && !Symbol.isUndefined())
ie = Asm.symbol_end(); it != ie; ++it) {
const MCSymbol &Symbol = it->getSymbol();
- // Ignore assembler temporaries.
- if (it->getSymbol().isTemporary())
+ // Ignore non-linker visible symbols.
+ if (!Asm.isSymbolLinkerVisible(it))
continue;
if (it->isExternal() || Symbol.isUndefined())
// The section data starts after the header, the segment load command (and
// section headers) and the symbol table.
unsigned NumLoadCommands = 1;
- uint64_t LoadCommandsSize =
+ uint64_t LoadCommandsSize = Is64Bit ?
+ SegmentLoadCommand64Size + NumSections * Section64Size :
SegmentLoadCommand32Size + NumSections * Section32Size;
// Add the symbol table load command sizes, if used.
// Compute the total size of the section data, as well as its file size and
// vm size.
- uint64_t SectionDataStart = Header32Size + LoadCommandsSize;
+ uint64_t SectionDataStart = (Is64Bit ? Header64Size : Header32Size)
+ + LoadCommandsSize;
uint64_t SectionDataSize = 0;
uint64_t SectionDataFileSize = 0;
uint64_t VMSize = 0;
SectionDataFileSize += SectionDataPadding;
// Write the prolog, starting with the header and load command...
- WriteHeader32(NumLoadCommands, LoadCommandsSize,
- Asm.getSubsectionsViaSymbols());
- WriteSegmentLoadCommand32(NumSections, VMSize,
- SectionDataStart, SectionDataSize);
+ WriteHeader(NumLoadCommands, LoadCommandsSize,
+ Asm.getSubsectionsViaSymbols());
+ WriteSegmentLoadCommand(NumSections, VMSize,
+ SectionDataStart, SectionDataSize);
- // ... and then the section headers.
- //
- // We also compute the section relocations while we do this. Note that
- // computing relocation info will also update the fixup to have the correct
- // value; this will overwrite the appropriate data in the fragment when it
- // is written.
- std::vector<MachRelocationEntry> RelocInfos;
- uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize;
for (MCAssembler::iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it) {
MCSectionData &SD = *it;
-
- // The assembler writes relocations in the reverse order they were seen.
- //
- // FIXME: It is probably more complicated than this.
- unsigned NumRelocsStart = RelocInfos.size();
- for (MCSectionData::reverse_iterator it2 = SD.rbegin(),
- ie2 = SD.rend(); it2 != ie2; ++it2)
+ for (MCSectionData::iterator it2 = SD.begin(),
+ ie2 = SD.end(); it2 != ie2; ++it2)
if (MCDataFragment *DF = dyn_cast<MCDataFragment>(&*it2))
for (unsigned i = 0, e = DF->fixup_size(); i != e; ++i)
- ComputeRelocationInfo(Asm, *DF, DF->getFixups()[e - i - 1],
- RelocInfos);
+ ComputeRelocationInfo(Asm, *DF, DF->getFixups()[i]);
+ }
- unsigned NumRelocs = RelocInfos.size() - NumRelocsStart;
- uint64_t SectionStart = SectionDataStart + SD.getAddress();
- WriteSection32(SD, SectionStart, RelocTableEnd, NumRelocs);
+ // ... and then the section headers.
+ uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize;
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ std::vector<MachRelocationEntry> &Relocs = Relocations[it];
+ unsigned NumRelocs = Relocs.size();
+ uint64_t SectionStart = SectionDataStart + it->getAddress();
+ WriteSection(*it, SectionStart, RelocTableEnd, NumRelocs);
RelocTableEnd += NumRelocs * RelocationInfoSize;
}
// The string table is written after symbol table.
uint64_t StringTableOffset =
- SymbolTableOffset + NumSymTabSymbols * Nlist32Size;
+ SymbolTableOffset + NumSymTabSymbols * (Is64Bit ? Nlist64Size :
+ Nlist32Size);
WriteSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols,
StringTableOffset, StringTable.size());
WriteZeros(SectionDataPadding);
// Write the relocation entries.
- for (unsigned i = 0, e = RelocInfos.size(); i != e; ++i) {
- Write32(RelocInfos[i].Word0);
- Write32(RelocInfos[i].Word1);
+ for (MCAssembler::iterator it = Asm.begin(),
+ ie = Asm.end(); it != ie; ++it) {
+ // Write the section relocation entries, in reverse order to match 'as'
+ // (approximately, the exact algorithm is more complicated than this).
+ std::vector<MachRelocationEntry> &Relocs = Relocations[it];
+ for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
+ Write32(Relocs[e - i - 1].Word0);
+ Write32(Relocs[e - i - 1].Word1);
+ }
}
// Write the symbol table data, if used.
// special handling.
const MCSectionMachO &Section =
static_cast<const MCSectionMachO&>(it->SectionData->getSection());
- unsigned Type =
- Section.getTypeAndAttributes() & MCSectionMachO::SECTION_TYPE;
- if (Type == MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS) {
+ if (Section.getType() == MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS) {
// If this symbol is defined and internal, mark it as such.
if (it->Symbol->isDefined() &&
!Asm.getSymbolData(*it->Symbol).isExternal()) {
// Write the symbol table entries.
for (unsigned i = 0, e = LocalSymbolData.size(); i != e; ++i)
- WriteNlist32(LocalSymbolData[i]);
+ WriteNlist(LocalSymbolData[i]);
for (unsigned i = 0, e = ExternalSymbolData.size(); i != e; ++i)
- WriteNlist32(ExternalSymbolData[i]);
+ WriteNlist(ExternalSymbolData[i]);
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
- WriteNlist32(UndefinedSymbolData[i]);
+ WriteNlist(UndefinedSymbolData[i]);
// Write the string table.
OS << StringTable.str();
MCAssembler::~MCAssembler() {
}
+static bool isScatteredFixupFullyResolvedSimple(const MCAssembler &Asm,
+ const MCAsmFixup &Fixup,
+ const MCDataFragment *DF,
+ const MCValue Target,
+ const MCSection *BaseSection) {
+ // The effective fixup address is
+ // addr(atom(A)) + offset(A)
+ // - addr(atom(B)) - offset(B)
+ // - addr(<base symbol>) + <fixup offset from base symbol>
+ // and the offsets are not relocatable, so the fixup is fully resolved when
+ // addr(atom(A)) - addr(atom(B)) - addr(<base symbol>)) == 0.
+ //
+ // The simple (Darwin, except on x86_64) way of dealing with this was to
+ // assume that any reference to a temporary symbol *must* be a temporary
+ // symbol in the same atom, unless the sections differ. Therefore, any PCrel
+ // relocation to a temporary symbol (in the same section) is fully
+ // resolved. This also works in conjunction with absolutized .set, which
+ // requires the compiler to use .set to absolutize the differences between
+ // symbols which the compiler knows to be assembly time constants, so we don't
+ // need to worry about consider symbol differences fully resolved.
+
+ // Non-relative fixups are only resolved if constant.
+ if (!BaseSection)
+ return Target.isAbsolute();
+
+ // Otherwise, relative fixups are only resolved if not a difference and the
+ // target is a temporary in the same section.
+ if (Target.isAbsolute() || Target.getSymB())
+ return false;
+
+ const MCSymbol *A = &Target.getSymA()->getSymbol();
+ if (!A->isTemporary() || !A->isInSection() ||
+ &A->getSection() != BaseSection)
+ return false;
+
+ return true;
+}
+
+static bool isScatteredFixupFullyResolved(const MCAssembler &Asm,
+ const MCAsmFixup &Fixup,
+ const MCDataFragment *DF,
+ const MCValue Target,
+ const MCSymbolData *BaseSymbol) {
+ // The effective fixup address is
+ // addr(atom(A)) + offset(A)
+ // - addr(atom(B)) - offset(B)
+ // - addr(BaseSymbol) + <fixup offset from base symbol>
+ // and the offsets are not relocatable, so the fixup is fully resolved when
+ // addr(atom(A)) - addr(atom(B)) - addr(BaseSymbol) == 0.
+ //
+ // Note that "false" is almost always conservatively correct (it means we emit
+ // a relocation which is unnecessary), except when it would force us to emit a
+ // relocation which the target cannot encode.
+
+ const MCSymbolData *A_Base = 0, *B_Base = 0;
+ if (const MCSymbolRefExpr *A = Target.getSymA()) {
+ // Modified symbol references cannot be resolved.
+ if (A->getKind() != MCSymbolRefExpr::VK_None)
+ return false;
+
+ A_Base = Asm.getAtom(&Asm.getSymbolData(A->getSymbol()));
+ if (!A_Base)
+ return false;
+ }
+
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ // Modified symbol references cannot be resolved.
+ if (B->getKind() != MCSymbolRefExpr::VK_None)
+ return false;
+
+ B_Base = Asm.getAtom(&Asm.getSymbolData(B->getSymbol()));
+ if (!B_Base)
+ return false;
+ }
+
+ // If there is no base, A and B have to be the same atom for this fixup to be
+ // fully resolved.
+ if (!BaseSymbol)
+ return A_Base == B_Base;
+
+ // Otherwise, B must be missing and A must be the base.
+ return !B_Base && BaseSymbol == A_Base;
+}
+
+bool MCAssembler::isSymbolLinkerVisible(const MCSymbolData *SD) const {
+ // Non-temporary labels should always be visible to the linker.
+ if (!SD->getSymbol().isTemporary())
+ return true;
+
+ // Absolute temporary labels are never visible.
+ if (!SD->getFragment())
+ return false;
+
+ // Otherwise, check if the section requires symbols even for temporary labels.
+ return getBackend().doesSectionRequireSymbols(
+ SD->getFragment()->getParent()->getSection());
+}
+
+const MCSymbolData *MCAssembler::getAtomForAddress(const MCSectionData *Section,
+ uint64_t Address) const {
+ const MCSymbolData *Best = 0;
+ for (MCAssembler::const_symbol_iterator it = symbol_begin(),
+ ie = symbol_end(); it != ie; ++it) {
+ // Ignore non-linker visible symbols.
+ if (!isSymbolLinkerVisible(it))
+ continue;
+
+ // Ignore symbols not in the same section.
+ if (!it->getFragment() || it->getFragment()->getParent() != Section)
+ continue;
+
+ // Otherwise, find the closest symbol preceding this address (ties are
+ // resolved in favor of the last defined symbol).
+ if (it->getAddress() <= Address &&
+ (!Best || it->getAddress() >= Best->getAddress()))
+ Best = it;
+ }
+
+ return Best;
+}
+
+const MCSymbolData *MCAssembler::getAtom(const MCSymbolData *SD) const {
+ // Linker visible symbols define atoms.
+ if (isSymbolLinkerVisible(SD))
+ return SD;
+
+ // Absolute and undefined symbols have no defining atom.
+ if (!SD->getFragment())
+ return 0;
+
+ // Otherwise, search by address.
+ return getAtomForAddress(SD->getFragment()->getParent(), SD->getAddress());
+}
+
bool MCAssembler::EvaluateFixup(const MCAsmLayout &Layout, MCAsmFixup &Fixup,
MCDataFragment *DF,
MCValue &Target, uint64_t &Value) const {
Value = Target.getConstant();
- // FIXME: This "resolved" check isn't quite right. The assumption is that if
- // we have a PCrel access to a temporary, then that temporary is in the same
- // atom, and so the value is resolved. We need explicit atom's to implement
- // this more precisely.
bool IsResolved = true, IsPCRel = isFixupKindPCRel(Fixup.Kind);
- if (const MCSymbol *Symbol = Target.getSymA()) {
- if (Symbol->isDefined())
- Value += getSymbolData(*Symbol).getAddress();
+ if (const MCSymbolRefExpr *A = Target.getSymA()) {
+ if (A->getSymbol().isDefined())
+ Value += getSymbolData(A->getSymbol()).getAddress();
else
IsResolved = false;
-
- // With scattered symbols, we assume anything that isn't a PCrel temporary
- // access can have an arbitrary value.
- if (getBackend().hasScatteredSymbols() &&
- (!IsPCRel || !Symbol->isTemporary()))
- IsResolved = false;
}
- if (const MCSymbol *Symbol = Target.getSymB()) {
- if (Symbol->isDefined())
- Value -= getSymbolData(*Symbol).getAddress();
+ if (const MCSymbolRefExpr *B = Target.getSymB()) {
+ if (B->getSymbol().isDefined())
+ Value -= getSymbolData(B->getSymbol()).getAddress();
else
IsResolved = false;
+ }
- // With scattered symbols, we assume anything that isn't a PCrel temporary
- // access can have an arbitrary value.
- if (getBackend().hasScatteredSymbols() &&
- (!IsPCRel || !Symbol->isTemporary()))
- IsResolved = false;
+ // If we are using scattered symbols, determine whether this value is actually
+ // resolved; scattering may cause atoms to move.
+ if (IsResolved && getBackend().hasScatteredSymbols()) {
+ if (getBackend().hasReliableSymbolDifference()) {
+ // If this is a PCrel relocation, find the base atom (identified by its
+ // symbol) that the fixup value is relative to.
+ const MCSymbolData *BaseSymbol = 0;
+ if (IsPCRel) {
+ BaseSymbol = getAtomForAddress(
+ DF->getParent(), DF->getAddress() + Fixup.Offset);
+ if (!BaseSymbol)
+ IsResolved = false;
+ }
+
+ if (IsResolved)
+ IsResolved = isScatteredFixupFullyResolved(*this, Fixup, DF, Target,
+ BaseSymbol);
+ } else {
+ const MCSection *BaseSection = 0;
+ if (IsPCRel)
+ BaseSection = &DF->getParent()->getSection();
+
+ IsResolved = isScatteredFixupFullyResolvedSimple(*this, Fixup, DF, Target,
+ BaseSection);
+ }
}
if (IsPCRel)
dump(); });
// Write the object file.
- MachObjectWriter MOW(OS);
+ //
+ // FIXME: Factor out MCObjectWriter.
+ bool Is64Bit = StringRef(getBackend().getTarget().getName()) == "x86-64";
+ MachObjectWriter MOW(OS, Is64Bit);
MOW.WriteObject(*this);
OS.flush();
projects / oota-llvm.git / blobdiff