#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MachO.h"
+#include "llvm/Support/raw_ostream.h"
#include <vector>
using namespace llvm;
bool MachObjectWriter::
doesSymbolRequireExternRelocation(const MCSymbolData *SD) {
// Undefined symbols are always extern.
- if (SD->Symbol->isUndefined())
+ if (SD->getSymbol().isUndefined())
return true;
// References to weak definitions require external relocation entries; the
MCValue Target;
- if (!S.getVariableValue()->EvaluateAsRelocatable(Target, &Layout))
+ if (!S.getVariableValue()->EvaluateAsRelocatable(Target, &Layout, nullptr))
report_fatal_error("unable to evaluate offset for variable '" +
S.getName() + "'");
assert(OS.tell() - Start == sizeof(MachO::dysymtab_command));
}
+MachObjectWriter::MachSymbolData *
+MachObjectWriter::findSymbolData(const MCSymbol &Sym) {
+ for (auto &Entry : LocalSymbolData)
+ if (&Entry.SymbolData->getSymbol() == &Sym)
+ return &Entry;
+
+ for (auto &Entry : ExternalSymbolData)
+ if (&Entry.SymbolData->getSymbol() == &Sym)
+ return &Entry;
+
+ for (auto &Entry : UndefinedSymbolData)
+ if (&Entry.SymbolData->getSymbol() == &Sym)
+ return &Entry;
+
+ return nullptr;
+}
+
void MachObjectWriter::WriteNlist(MachSymbolData &MSD,
const MCAsmLayout &Layout) {
MCSymbolData &Data = *MSD.SymbolData;
- const MCSymbol &Symbol = Data.getSymbol();
+ const MCSymbol *Symbol = &Data.getSymbol();
+ const MCSymbol *AliasedSymbol = &Symbol->AliasedSymbol();
+ uint8_t SectionIndex = MSD.SectionIndex;
uint8_t Type = 0;
uint16_t Flags = Data.getFlags();
uint64_t Address = 0;
+ bool IsAlias = Symbol != AliasedSymbol;
+
+ MachSymbolData *AliaseeInfo;
+ if (IsAlias) {
+ AliaseeInfo = findSymbolData(*AliasedSymbol);
+ if (AliaseeInfo)
+ SectionIndex = AliaseeInfo->SectionIndex;
+ Symbol = AliasedSymbol;
+ }
// Set the N_TYPE bits. See <mach-o/nlist.h>.
//
// FIXME: Are the prebound or indirect fields possible here?
- if (Symbol.isUndefined())
+ if (IsAlias && Symbol->isUndefined())
+ Type = MachO::N_INDR;
+ else if (Symbol->isUndefined())
Type = MachO::N_UNDF;
- else if (Symbol.isAbsolute())
+ else if (Symbol->isAbsolute())
Type = MachO::N_ABS;
else
Type = MachO::N_SECT;
Type |= MachO::N_PEXT;
// Set external bit.
- if (Data.isExternal() || Symbol.isUndefined())
+ if (Data.isExternal() || (!IsAlias && Symbol->isUndefined()))
Type |= MachO::N_EXT;
// Compute the symbol address.
- if (Symbol.isDefined()) {
+ if (IsAlias && Symbol->isUndefined())
+ Address = AliaseeInfo->StringIndex;
+ else if (Symbol->isDefined())
Address = getSymbolAddress(&Data, Layout);
- } else if (Data.isCommon()) {
+ else if (Data.isCommon()) {
// Common symbols are encoded with the size in the address
// field, and their alignment in the flags.
Address = Data.getCommonSize();
assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
if (Log2Size > 15)
report_fatal_error("invalid 'common' alignment '" +
- Twine(Align) + "' for '" + Symbol.getName() + "'",
+ Twine(Align) + "' for '" + Symbol->getName() + "'",
false);
// FIXME: Keep this mask with the SymbolFlags enumeration.
Flags = (Flags & 0xF0FF) | (Log2Size << 8);
}
}
+ if (Layout.getAssembler().isThumbFunc(Symbol))
+ Flags |= SF_ThumbFunc;
+
// struct nlist (12 bytes)
Write32(MSD.StringIndex);
Write8(Type);
- Write8(MSD.SectionIndex);
+ Write8(SectionIndex);
// The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
// value.
static unsigned ComputeLinkerOptionsLoadCommandSize(
const std::vector<std::string> &Options, bool is64Bit)
{
- unsigned Size = sizeof(MachO::linker_options_command);
+ unsigned Size = sizeof(MachO::linker_option_command);
for (unsigned i = 0, e = Options.size(); i != e; ++i)
Size += Options[i].size() + 1;
return RoundUpToAlignment(Size, is64Bit ? 8 : 4);
uint64_t Start = OS.tell();
(void) Start;
- Write32(MachO::LC_LINKER_OPTIONS);
+ Write32(MachO::LC_LINKER_OPTION);
Write32(Size);
Write32(Options.size());
- uint64_t BytesWritten = sizeof(MachO::linker_options_command);
+ uint64_t BytesWritten = sizeof(MachO::linker_option_command);
for (unsigned i = 0, e = Options.size(); i != e; ++i) {
// Write each string, including the null byte.
const std::string &Option = Options[i];
assert(OS.tell() - Start == Size);
}
-
-void MachObjectWriter::RecordRelocation(const MCAssembler &Asm,
+void MachObjectWriter::RecordRelocation(MCAssembler &Asm,
const MCAsmLayout &Layout,
const MCFragment *Fragment,
- const MCFixup &Fixup,
- MCValue Target,
- bool &IsPCRel,
- uint64_t &FixedValue) {
+ const MCFixup &Fixup, MCValue Target,
+ bool &IsPCRel, uint64_t &FixedValue) {
TargetObjectWriter->RecordRelocation(this, Asm, Layout, Fragment, Fixup,
Target, FixedValue);
}
}
/// ComputeSymbolTable - Compute the symbol table data
-///
-/// \param StringTable [out] - The string table data.
-/// \param StringIndexMap [out] - Map from symbol names to offsets in the
-/// string table.
-void MachObjectWriter::
-ComputeSymbolTable(MCAssembler &Asm, SmallString<256> &StringTable,
- std::vector<MachSymbolData> &LocalSymbolData,
- std::vector<MachSymbolData> &ExternalSymbolData,
- std::vector<MachSymbolData> &UndefinedSymbolData) {
+void MachObjectWriter::ComputeSymbolTable(
+ MCAssembler &Asm, std::vector<MachSymbolData> &LocalSymbolData,
+ std::vector<MachSymbolData> &ExternalSymbolData,
+ std::vector<MachSymbolData> &UndefinedSymbolData) {
// Build section lookup table.
DenseMap<const MCSection*, uint8_t> SectionIndexMap;
unsigned Index = 1;
SectionIndexMap[&it->getSection()] = Index;
assert(Index <= 256 && "Too many sections!");
- // Index 0 is always the empty string.
- StringMap<uint64_t> StringIndexMap;
- StringTable += '\x00';
+ // Build the string table.
+ for (MCSymbolData &SD : Asm.symbols()) {
+ const MCSymbol &Symbol = SD.getSymbol();
+ if (!Asm.isSymbolLinkerVisible(Symbol))
+ continue;
+
+ StringTable.add(Symbol.getName());
+ }
+ StringTable.finalize(StringTableBuilder::MachO);
- // Build the symbol arrays and the string table, but only for non-local
- // symbols.
+ // Build the symbol arrays but only for non-local symbols.
//
- // The particular order that we collect the symbols and create the string
- // table, then sort the symbols is chosen to match 'as'. Even though it
- // doesn't matter for correctness, this is important for letting us diff .o
- // files.
+ // The particular order that we collect and then sort the symbols is chosen to
+ // match 'as'. Even though it doesn't matter for correctness, this is
+ // important for letting us diff .o files.
for (MCSymbolData &SD : Asm.symbols()) {
const MCSymbol &Symbol = SD.getSymbol();
// Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(SD.getSymbol()))
+ if (!Asm.isSymbolLinkerVisible(Symbol))
continue;
if (!SD.isExternal() && !Symbol.isUndefined())
continue;
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
- if (!Entry) {
- Entry = StringTable.size();
- StringTable += Symbol.getName();
- StringTable += '\x00';
- }
-
MachSymbolData MSD;
MSD.SymbolData = &SD;
- MSD.StringIndex = Entry;
+ MSD.StringIndex = StringTable.getOffset(Symbol.getName());
if (Symbol.isUndefined()) {
MSD.SectionIndex = 0;
const MCSymbol &Symbol = SD.getSymbol();
// Ignore non-linker visible symbols.
- if (!Asm.isSymbolLinkerVisible(SD.getSymbol()))
+ if (!Asm.isSymbolLinkerVisible(Symbol))
continue;
if (SD.isExternal() || Symbol.isUndefined())
continue;
- uint64_t &Entry = StringIndexMap[Symbol.getName()];
- if (!Entry) {
- Entry = StringTable.size();
- StringTable += Symbol.getName();
- StringTable += '\x00';
- }
-
MachSymbolData MSD;
MSD.SymbolData = &SD;
- MSD.StringIndex = Entry;
+ MSD.StringIndex = StringTable.getOffset(Symbol.getName());
if (Symbol.isAbsolute()) {
MSD.SectionIndex = 0;
for (unsigned i = 0, e = UndefinedSymbolData.size(); i != e; ++i)
UndefinedSymbolData[i].SymbolData->setIndex(Index++);
- // The string table is padded to a multiple of 4.
- while (StringTable.size() % 4)
- StringTable += '\x00';
+ for (const MCSectionData &SD : Asm) {
+ std::vector<RelAndSymbol> &Relocs = Relocations[&SD];
+ for (RelAndSymbol &Rel : Relocs) {
+ if (!Rel.Sym)
+ continue;
+
+ // Set the Index and the IsExtern bit.
+ unsigned Index = Rel.Sym->getIndex();
+ assert(isInt<24>(Index));
+ if (IsLittleEndian)
+ Rel.MRE.r_word1 = (Rel.MRE.r_word1 & (-1 << 24)) | Index | (1 << 27);
+ else
+ Rel.MRE.r_word1 = (Rel.MRE.r_word1 & 0xff) | Index << 8 | (1 << 4);
+ }
+ }
}
void MachObjectWriter::computeSectionAddresses(const MCAssembler &Asm,
// and neither symbol is external, mark the variable as absolute.
const MCExpr *Expr = SD.getSymbol().getVariableValue();
MCValue Value;
- if (Expr->EvaluateAsRelocatable(Value, &Layout)) {
+ if (Expr->EvaluateAsRelocatable(Value, &Layout, nullptr)) {
if (Value.getSymA() && Value.getSymB())
const_cast<MCSymbol*>(&SD.getSymbol())->setAbsolute();
}
// Mark symbol difference expressions in variables (from .set or = directives)
// as absolute.
markAbsoluteVariableSymbols(Asm, Layout);
-
- // Compute symbol table information and bind symbol indices.
- ComputeSymbolTable(Asm, StringTable, LocalSymbolData, ExternalSymbolData,
- UndefinedSymbolData);
}
bool MachObjectWriter::
return false;
}
+ // If they are not in the same section, we can't compute the diff.
+ if (&SecA != &SecB)
+ return false;
+
const MCFragment *FA = Asm.getSymbolData(SA).getFragment();
// Bail if the symbol has no fragment.
return false;
A_Base = FA->getAtom();
- if (!A_Base)
- return false;
-
B_Base = FB.getAtom();
- if (!B_Base)
- return false;
// If the atoms are the same, they are guaranteed to have the same address.
if (A_Base == B_Base)
void MachObjectWriter::WriteObject(MCAssembler &Asm,
const MCAsmLayout &Layout) {
+ // Compute symbol table information and bind symbol indices.
+ ComputeSymbolTable(Asm, LocalSymbolData, ExternalSymbolData,
+ UndefinedSymbolData);
+
unsigned NumSections = Asm.size();
const MCAssembler::VersionMinInfoType &VersionInfo =
Layout.getAssembler().getVersionMinInfo();
uint64_t RelocTableEnd = SectionDataStart + SectionDataFileSize;
for (MCAssembler::const_iterator it = Asm.begin(),
ie = Asm.end(); it != ie; ++it) {
- std::vector<MachO::any_relocation_info> &Relocs = Relocations[it];
+ std::vector<RelAndSymbol> &Relocs = Relocations[it];
unsigned NumRelocs = Relocs.size();
uint64_t SectionStart = SectionDataStart + getSectionAddress(it);
WriteSection(Asm, Layout, *it, SectionStart, RelocTableEnd, NumRelocs);
sizeof(MachO::nlist_64) :
sizeof(MachO::nlist));
WriteSymtabLoadCommand(SymbolTableOffset, NumSymTabSymbols,
- StringTableOffset, StringTable.size());
+ StringTableOffset, StringTable.data().size());
WriteDysymtabLoadCommand(FirstLocalSymbol, NumLocalSymbols,
FirstExternalSymbol, NumExternalSymbols,
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<MachO::any_relocation_info> &Relocs = Relocations[it];
+ std::vector<RelAndSymbol> &Relocs = Relocations[it];
for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
- Write32(Relocs[e - i - 1].r_word0);
- Write32(Relocs[e - i - 1].r_word1);
+ Write32(Relocs[e - i - 1].MRE.r_word0);
+ Write32(Relocs[e - i - 1].MRE.r_word1);
}
}
WriteNlist(UndefinedSymbolData[i], Layout);
// Write the string table.
- OS << StringTable.str();
+ OS << StringTable.data();
}
}
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