#define LLVM_CODEGEN_ELFWRITER_H
#include "llvm/CodeGen/MachineFunctionPass.h"
+#include <list>
namespace llvm {
class GlobalVariable;
~ELFWriter();
+ typedef std::vector<unsigned char> DataBuffer;
+
protected:
ELFWriter(std::ostream &O, TargetMachine &TM);
bool doFinalization(Module &M);
private:
- // The buffer we are accumulating the file into. Note that this should be
+ // The buffer we accumulate the file header into. Note that this should be
// changed into something much more efficient later (and the bytecode writer
// as well!).
- std::vector<unsigned char> OutputBuffer;
+ DataBuffer FileHeader;
/// ELFSection - This struct contains information about each section that is
- /// emitted to the OutputBuffer. This is eventually turned into the section
- /// header table at the end of the file.
+ /// emitted to the file. This is eventually turned into the section header
+ /// table at the end of the file.
struct ELFSection {
std::string Name; // Name of the section.
unsigned NameIdx; // Index in .shstrtab of name, once emitted.
unsigned Align;
unsigned EntSize;
+ /// SectionIdx - The number of the section in the Section Table.
+ ///
+ unsigned short SectionIdx;
+
+ /// SectionData - The actual data for this section which we are building
+ /// up for emission to the file.
+ DataBuffer SectionData;
+
enum { SHT_NULL = 0, SHT_PROGBITS = 1, SHT_SYMTAB = 2, SHT_STRTAB = 3,
SHT_RELA = 4, SHT_HASH = 5, SHT_DYNAMIC = 6, SHT_NOTE = 7,
SHT_NOBITS = 8, SHT_REL = 9, SHT_SHLIB = 10, SHT_DYNSYM = 11 };
SHF_TLS = 1 << 10,// Section holds thread-local data
};
- ELFSection(const char *name = "", unsigned offset = 0)
- : Name(name), Type(0), Flags(0), Addr(0), Offset(offset), Size(0),
+ ELFSection(const std::string &name)
+ : Name(name), Type(0), Flags(0), Addr(0), Offset(0), Size(0),
Link(0), Info(0), Align(0), EntSize(0) {
}
};
/// SectionList - This is the list of sections that we have emitted to the
/// file. Once the file has been completely built, the section header table
/// is constructed from this info.
- std::vector<ELFSection> SectionList;
+ std::list<ELFSection> SectionList;
+ unsigned NumSections; // Always = SectionList.size()
+
+ /// SectionLookup - This is a mapping from section name to section number in
+ /// the SectionList.
+ std::map<std::string, ELFSection*> SectionLookup;
+
+ /// getSection - Return the section with the specified name, creating a new
+ /// section if one does not already exist.
+ ELFSection &getSection(const std::string &Name) {
+ ELFSection *&SN = SectionLookup[Name];
+ if (SN) return *SN;
+
+ SectionList.push_back(Name);
+ SN = &SectionList.back();
+ SN->SectionIdx = NumSections++;
+ return *SN;
+ }
/// ELFSym - This struct contains information about each symbol that is
/// added to logical symbol table for the module. This is eventually
};
/// SymbolTable - This is the list of symbols we have emitted to the file.
- /// This actually gets rearranged before emission to OutputBuffer (to put
- /// the local symbols first in the list).
+ /// This actually gets rearranged before emission to the file (to put the
+ /// local symbols first in the list).
std::vector<ELFSym> SymbolTable;
- // As we accumulate the ELF file into OutputBuffer, we occasionally need to
- // keep track of locations to update later (e.g. the location of the section
- // table in the ELF header. These members keep track of the offset in
- // OffsetBuffer of these various pieces to update and other locations in the
- // file.
+ // As we complete the ELF file, we need to update fields in the ELF header
+ // (e.g. the location of the section table). These members keep track of
+ // the offset in ELFHeader of these various pieces to update and other
+ // locations in the file.
unsigned ELFHeader_e_shoff_Offset; // e_shoff in ELF header.
unsigned ELFHeader_e_shstrndx_Offset; // e_shstrndx in ELF header.
unsigned ELFHeader_e_shnum_Offset; // e_shnum in ELF header.
+
// align - Emit padding into the file until the current output position is
// aligned to the specified power of two boundary.
- void align(unsigned Boundary) {
+ static void align(DataBuffer &Output, unsigned Boundary) {
assert(Boundary && (Boundary & (Boundary-1)) == 0 &&
"Must align to 2^k boundary");
- while (OutputBuffer.size() & (Boundary-1))
- outbyte(0xAB);
+ size_t Size = Output.size();
+ if (Size & (Boundary-1)) {
+ // Add padding to get alignment to the correct place.
+ size_t Pad = Boundary-(Size & (Boundary-1));
+ Output.resize(Size+Pad);
+ }
}
- void outbyte(unsigned char X) { OutputBuffer.push_back(X); }
- void outhalf(unsigned short X) {
+ static void outbyte(DataBuffer &Output, unsigned char X) {
+ Output.push_back(X);
+ }
+ void outhalf(DataBuffer &Output, unsigned short X) {
if (isLittleEndian) {
- OutputBuffer.push_back(X&255);
- OutputBuffer.push_back(X >> 8);
+ Output.push_back(X&255);
+ Output.push_back(X >> 8);
} else {
- OutputBuffer.push_back(X >> 8);
- OutputBuffer.push_back(X&255);
+ Output.push_back(X >> 8);
+ Output.push_back(X&255);
}
}
- void outword(unsigned X) {
+ void outword(DataBuffer &Output, unsigned X) {
if (isLittleEndian) {
- OutputBuffer.push_back((X >> 0) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 24) & 255);
+ Output.push_back((X >> 0) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 24) & 255);
} else {
- OutputBuffer.push_back((X >> 24) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 0) & 255);
+ Output.push_back((X >> 24) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 0) & 255);
}
}
- void outxword(uint64_t X) {
+ void outxword(DataBuffer &Output, uint64_t X) {
if (isLittleEndian) {
- OutputBuffer.push_back((X >> 0) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 24) & 255);
- OutputBuffer.push_back((X >> 32) & 255);
- OutputBuffer.push_back((X >> 40) & 255);
- OutputBuffer.push_back((X >> 48) & 255);
- OutputBuffer.push_back((X >> 56) & 255);
+ Output.push_back((X >> 0) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 24) & 255);
+ Output.push_back((X >> 32) & 255);
+ Output.push_back((X >> 40) & 255);
+ Output.push_back((X >> 48) & 255);
+ Output.push_back((X >> 56) & 255);
} else {
- OutputBuffer.push_back((X >> 56) & 255);
- OutputBuffer.push_back((X >> 48) & 255);
- OutputBuffer.push_back((X >> 40) & 255);
- OutputBuffer.push_back((X >> 32) & 255);
- OutputBuffer.push_back((X >> 24) & 255);
- OutputBuffer.push_back((X >> 16) & 255);
- OutputBuffer.push_back((X >> 8) & 255);
- OutputBuffer.push_back((X >> 0) & 255);
+ Output.push_back((X >> 56) & 255);
+ Output.push_back((X >> 48) & 255);
+ Output.push_back((X >> 40) & 255);
+ Output.push_back((X >> 32) & 255);
+ Output.push_back((X >> 24) & 255);
+ Output.push_back((X >> 16) & 255);
+ Output.push_back((X >> 8) & 255);
+ Output.push_back((X >> 0) & 255);
}
}
- void outaddr32(unsigned X) {
- outword(X);
+ void outaddr32(DataBuffer &Output, unsigned X) {
+ outword(Output, X);
}
- void outaddr64(uint64_t X) {
- outxword(X);
+ void outaddr64(DataBuffer &Output, uint64_t X) {
+ outxword(Output, X);
}
- void outaddr(uint64_t X) {
+ void outaddr(DataBuffer &Output, uint64_t X) {
if (!is64Bit)
- outword((unsigned)X);
+ outword(Output, (unsigned)X);
else
- outxword(X);
+ outxword(Output, X);
}
// fix functions - Replace an existing entry at an offset.
- void fixhalf(unsigned short X, unsigned Offset) {
- unsigned char *P = &OutputBuffer[Offset];
+ void fixhalf(DataBuffer &Output, unsigned short X, unsigned Offset) {
+ unsigned char *P = &Output[Offset];
P[0] = (X >> (isLittleEndian ? 0 : 8)) & 255;
P[1] = (X >> (isLittleEndian ? 8 : 0)) & 255;
}
- void fixword(unsigned X, unsigned Offset) {
- unsigned char *P = &OutputBuffer[Offset];
+ void fixword(DataBuffer &Output, unsigned X, unsigned Offset) {
+ unsigned char *P = &Output[Offset];
P[0] = (X >> (isLittleEndian ? 0 : 24)) & 255;
P[1] = (X >> (isLittleEndian ? 8 : 16)) & 255;
P[2] = (X >> (isLittleEndian ? 16 : 8)) & 255;
P[3] = (X >> (isLittleEndian ? 24 : 0)) & 255;
}
- void fixaddr(uint64_t X, unsigned Offset) {
+ void fixaddr(DataBuffer &Output, uint64_t X, unsigned Offset) {
if (!is64Bit)
- fixword((unsigned)X, Offset);
+ fixword(Output, (unsigned)X, Offset);
else
assert(0 && "Emission of 64-bit data not implemented yet!");
}
void EmitSymbolTable();
void EmitSectionTableStringTable();
- void EmitSectionTable();
+ void OutputSectionsAndSectionTable();
};
}
/// functions to the ELF file.
class ELFCodeEmitter : public MachineCodeEmitter {
ELFWriter &EW;
- std::vector<unsigned char> &OutputBuffer;
+ ELFWriter::ELFSection *ES; // Section to write to.
+ std::vector<unsigned char> *OutBuffer;
size_t FnStart;
public:
- ELFCodeEmitter(ELFWriter &ew) : EW(ew), OutputBuffer(EW.OutputBuffer) {}
+ ELFCodeEmitter(ELFWriter &ew) : EW(ew), OutBuffer(0) {}
void startFunction(MachineFunction &F);
void finishFunction(MachineFunction &F);
assert(0 && "unimp");
}
virtual void emitByte(unsigned char B) {
- OutputBuffer.push_back(B);
+ OutBuffer->push_back(B);
}
virtual void emitWordAt(unsigned W, unsigned *Ptr) {
assert(0 && "ni");
assert(0 && "ni");
}
virtual uint64_t getCurrentPCValue() {
- return OutputBuffer.size();
+ return OutBuffer->size();
}
virtual uint64_t getCurrentPCOffset() {
- return OutputBuffer.size()-FnStart;
+ return OutBuffer->size()-FnStart;
}
void addRelocation(const MachineRelocation &MR) {
assert(0 && "relo not handled yet!");
void ELFCodeEmitter::startFunction(MachineFunction &F) {
// Align the output buffer to the appropriate alignment.
unsigned Align = 16; // FIXME: GENERICIZE!!
- ELFWriter::ELFSection &TextSection = EW.SectionList.back();
+ // Get the ELF Section that this function belongs in.
+ ES = &EW.getSection(".text");
+ ES->Type = ELFWriter::ELFSection::SHT_PROGBITS;
+ ES->Flags = ELFWriter::ELFSection::SHF_EXECINSTR |
+ ELFWriter::ELFSection::SHF_ALLOC;
+ OutBuffer = &ES->SectionData;
// Upgrade the section alignment if required.
- if (TextSection.Align < Align) TextSection.Align = Align;
+ if (ES->Align < Align) ES->Align = Align;
// Add padding zeros to the end of the buffer to make sure that the
// function will start on the correct byte alignment within the section.
- size_t SectionOff = OutputBuffer.size()-TextSection.Offset;
- if (SectionOff & (Align-1)) {
- // Add padding to get alignment to the correct place.
- size_t Pad = Align-(SectionOff & (Align-1));
- OutputBuffer.resize(OutputBuffer.size()+Pad);
- }
+ size_t SectionOff = OutBuffer->size();
+ ELFWriter::align(*OutBuffer, Align);
- FnStart = OutputBuffer.size();
+ FnStart = OutBuffer->size();
}
/// finishFunction - This callback is invoked after the function is completely
FnSym.SetBind(ELFWriter::ELFSym::STB_LOCAL);
break;
}
-
+
+ ES->Size = OutBuffer->size();
+
FnSym.SetType(ELFWriter::ELFSym::STT_FUNC);
- FnSym.SectionIdx = EW.SectionList.size()-1; // .text section.
- // Value = Offset from start of .text
- FnSym.Value = FnStart - EW.SectionList.back().Offset;
- FnSym.Size = OutputBuffer.size()-FnStart;
+ FnSym.SectionIdx = ES->SectionIdx;
+ FnSym.Value = FnStart; // Value = Offset from start of Section.
+ FnSym.Size = OutBuffer->size()-FnStart;
// Finally, add it to the symtab.
EW.SymbolTable.push_back(FnSym);
// Create the machine code emitter object for this target.
MCE = new ELFCodeEmitter(*this);
+ NumSections = 0;
}
ELFWriter::~ELFWriter() {
bool ELFWriter::doInitialization(Module &M) {
Mang = new Mangler(M);
- outbyte(0x7F); // EI_MAG0
- outbyte('E'); // EI_MAG1
- outbyte('L'); // EI_MAG2
- outbyte('F'); // EI_MAG3
- outbyte(is64Bit ? 2 : 1); // EI_CLASS
- outbyte(isLittleEndian ? 1 : 2); // EI_DATA
- outbyte(1); // EI_VERSION
- for (unsigned i = OutputBuffer.size(); i != 16; ++i)
- outbyte(0); // EI_PAD up to 16 bytes.
+ // Local alias to shortenify coming code.
+ std::vector<unsigned char> &FH = FileHeader;
+
+ outbyte(FH, 0x7F); // EI_MAG0
+ outbyte(FH, 'E'); // EI_MAG1
+ outbyte(FH, 'L'); // EI_MAG2
+ outbyte(FH, 'F'); // EI_MAG3
+ outbyte(FH, is64Bit ? 2 : 1); // EI_CLASS
+ outbyte(FH, isLittleEndian ? 1 : 2); // EI_DATA
+ outbyte(FH, 1); // EI_VERSION
+ FH.resize(16); // EI_PAD up to 16 bytes.
// This should change for shared objects.
- outhalf(1); // e_type = ET_REL
- outhalf(e_machine); // e_machine = whatever the target wants
- outword(1); // e_version = 1
- outaddr(0); // e_entry = 0 -> no entry point in .o file
- outaddr(0); // e_phoff = 0 -> no program header for .o
+ outhalf(FH, 1); // e_type = ET_REL
+ outhalf(FH, e_machine); // e_machine = whatever the target wants
+ outword(FH, 1); // e_version = 1
+ outaddr(FH, 0); // e_entry = 0 -> no entry point in .o file
+ outaddr(FH, 0); // e_phoff = 0 -> no program header for .o
- ELFHeader_e_shoff_Offset = OutputBuffer.size();
- outaddr(0); // e_shoff
- outword(e_flags); // e_flags = whatever the target wants
+ ELFHeader_e_shoff_Offset = FH.size();
+ outaddr(FH, 0); // e_shoff
+ outword(FH, e_flags); // e_flags = whatever the target wants
- outhalf(is64Bit ? 64 : 52); // e_ehsize = ELF header size
- outhalf(0); // e_phentsize = prog header entry size
- outhalf(0); // e_phnum = # prog header entries = 0
- outhalf(is64Bit ? 64 : 40); // e_shentsize = sect header entry size
+ outhalf(FH, is64Bit ? 64 : 52); // e_ehsize = ELF header size
+ outhalf(FH, 0); // e_phentsize = prog header entry size
+ outhalf(FH, 0); // e_phnum = # prog header entries = 0
+ outhalf(FH, is64Bit ? 64 : 40); // e_shentsize = sect hdr entry size
- ELFHeader_e_shnum_Offset = OutputBuffer.size();
- outhalf(0); // e_shnum = # of section header ents
- ELFHeader_e_shstrndx_Offset = OutputBuffer.size();
- outhalf(0); // e_shstrndx = Section # of '.shstrtab'
+ ELFHeader_e_shnum_Offset = FH.size();
+ outhalf(FH, 0); // e_shnum = # of section header ents
+ ELFHeader_e_shstrndx_Offset = FH.size();
+ outhalf(FH, 0); // e_shstrndx = Section # of '.shstrtab'
- // Add the null section.
- SectionList.push_back(ELFSection());
+ // Add the null section, which is required to be first in the file.
+ getSection("");
// Start up the symbol table. The first entry in the symtab is the null
// entry.
SymbolTable.push_back(ELFSym(0));
- SectionList.push_back(ELFSection(".text", OutputBuffer.size()));
-
return false;
}
}
// Set the idx of the .bss section
- BSSSym.SectionIdx = &BSSSection-&SectionList[0];
+ BSSSym.SectionIdx = BSSSection.SectionIdx;
SymbolTable.push_back(BSSSym);
// Reserve space in the .bss section for this symbol.
/// doFinalization - Now that the module has been completely processed, emit
/// the ELF file to 'O'.
bool ELFWriter::doFinalization(Module &M) {
- // Okay, the .text section has now been finalized. If it contains nothing, do
- // not emit it.
- uint64_t TextSize = OutputBuffer.size() - SectionList.back().Offset;
- if (TextSize == 0) {
- SectionList.pop_back();
- } else {
- ELFSection &Text = SectionList.back();
- Text.Size = TextSize;
- Text.Type = ELFSection::SHT_PROGBITS;
- Text.Flags = ELFSection::SHF_EXECINSTR | ELFSection::SHF_ALLOC;
- }
-
// Okay, the ELF header and .text sections have been completed, build the
// .data, .bss, and "common" sections next.
- SectionList.push_back(ELFSection(".data", OutputBuffer.size()));
- SectionList.push_back(ELFSection(".bss"));
- ELFSection &DataSection = *(SectionList.end()-2);
- ELFSection &BSSSection = SectionList.back();
- for (Module::global_iterator I = M.global_begin(), E = M.global_end();
- I != E; ++I)
- EmitGlobal(I, DataSection, BSSSection);
-
- // Finish up the data section.
+ ELFSection &DataSection = getSection(".data");
DataSection.Type = ELFSection::SHT_PROGBITS;
DataSection.Flags = ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC;
- // The BSS Section logically starts at the end of the Data Section (adjusted
- // to the required alignment of the BSSSection).
- BSSSection.Offset = DataSection.Offset+DataSection.Size;
+ ELFSection &BSSSection = getSection(".bss");
BSSSection.Type = ELFSection::SHT_NOBITS;
BSSSection.Flags = ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC;
- if (BSSSection.Align)
- BSSSection.Offset = (BSSSection.Offset+BSSSection.Align-1) &
- ~(BSSSection.Align-1);
+
+ for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+ I != E; ++I)
+ EmitGlobal(I, DataSection, BSSSection);
// Emit the symbol table now, if non-empty.
EmitSymbolTable();
// Emit the string table for the sections in the ELF file we have.
EmitSectionTableStringTable();
- // Emit the .o file section table.
- EmitSectionTable();
+ // Emit the sections to the .o file, and emit the section table for the file.
+ OutputSectionsAndSectionTable();
- // Emit the .o file to the specified stream.
- O.write((char*)&OutputBuffer[0], OutputBuffer.size());
-
- // Free the output buffer.
- std::vector<unsigned char>().swap(OutputBuffer);
+ // We are done with the abstract symbols.
+ SectionList.clear();
+ NumSections = 0;
// Release the name mangler object.
delete Mang; Mang = 0;
// FIXME: compact all local symbols to the start of the symtab.
unsigned FirstNonLocalSymbol = 1;
- SectionList.push_back(ELFSection(".strtab", OutputBuffer.size()));
- ELFSection &StrTab = SectionList.back();
+ ELFSection &StrTab = getSection(".strtab");
StrTab.Type = ELFSection::SHT_STRTAB;
StrTab.Align = 1;
+ DataBuffer &StrTabBuf = StrTab.SectionData;
+
// Set the zero'th symbol to a null byte, as required.
- outbyte(0);
+ outbyte(StrTabBuf, 0);
SymbolTable[0].NameIdx = 0;
unsigned Index = 1;
for (unsigned i = 1, e = SymbolTable.size(); i != e; ++i) {
SymbolTable[i].NameIdx = Index;
// Add the name to the output buffer, including the null terminator.
- OutputBuffer.insert(OutputBuffer.end(), Name.begin(), Name.end());
+ StrTabBuf.insert(StrTabBuf.end(), Name.begin(), Name.end());
// Add a null terminator.
- OutputBuffer.push_back(0);
+ StrTabBuf.push_back(0);
// Keep track of the number of bytes emitted to this section.
Index += Name.size()+1;
}
}
-
- StrTab.Size = OutputBuffer.size()-StrTab.Offset;
+ assert(Index == StrTabBuf.size());
+ StrTab.Size = Index;
// Now that we have emitted the string table and know the offset into the
// string table of each symbol, emit the symbol table itself.
- align(is64Bit ? 8 : 4);
-
- SectionList.push_back(ELFSection(".symtab", OutputBuffer.size()));
- ELFSection &SymTab = SectionList.back();
+ ELFSection &SymTab = getSection(".symtab");
SymTab.Type = ELFSection::SHT_SYMTAB;
SymTab.Align = is64Bit ? 8 : 4;
- SymTab.Link = SectionList.size()-2; // Section Index of .strtab.
+ SymTab.Link = SymTab.SectionIdx; // Section Index of .strtab.
SymTab.Info = FirstNonLocalSymbol; // First non-STB_LOCAL symbol.
SymTab.EntSize = 16; // Size of each symtab entry. FIXME: wrong for ELF64
+ DataBuffer &SymTabBuf = SymTab.SectionData;
if (!is64Bit) { // 32-bit and 64-bit formats are shuffled a bit.
for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) {
ELFSym &Sym = SymbolTable[i];
- outword(Sym.NameIdx);
- outaddr32(Sym.Value);
- outword(Sym.Size);
- outbyte(Sym.Info);
- outbyte(Sym.Other);
- outhalf(Sym.SectionIdx);
+ outword(SymTabBuf, Sym.NameIdx);
+ outaddr32(SymTabBuf, Sym.Value);
+ outword(SymTabBuf, Sym.Size);
+ outbyte(SymTabBuf, Sym.Info);
+ outbyte(SymTabBuf, Sym.Other);
+ outhalf(SymTabBuf, Sym.SectionIdx);
}
} else {
for (unsigned i = 0, e = SymbolTable.size(); i != e; ++i) {
ELFSym &Sym = SymbolTable[i];
- outword(Sym.NameIdx);
- outbyte(Sym.Info);
- outbyte(Sym.Other);
- outhalf(Sym.SectionIdx);
- outaddr64(Sym.Value);
- outxword(Sym.Size);
+ outword(SymTabBuf, Sym.NameIdx);
+ outbyte(SymTabBuf, Sym.Info);
+ outbyte(SymTabBuf, Sym.Other);
+ outhalf(SymTabBuf, Sym.SectionIdx);
+ outaddr64(SymTabBuf, Sym.Value);
+ outxword(SymTabBuf, Sym.Size);
}
}
- SymTab.Size = OutputBuffer.size()-SymTab.Offset;
+ SymTab.Size = SymTabBuf.size();
}
/// EmitSectionTableStringTable - This method adds and emits a section for the
/// section names.
void ELFWriter::EmitSectionTableStringTable() {
// First step: add the section for the string table to the list of sections:
- SectionList.push_back(ELFSection(".shstrtab", OutputBuffer.size()));
- SectionList.back().Type = ELFSection::SHT_STRTAB;
+ ELFSection &SHStrTab = getSection(".shstrtab");
+ SHStrTab.Type = ELFSection::SHT_STRTAB;
// Now that we know which section number is the .shstrtab section, update the
// e_shstrndx entry in the ELF header.
- fixhalf(SectionList.size()-1, ELFHeader_e_shstrndx_Offset);
+ fixhalf(FileHeader, SHStrTab.SectionIdx, ELFHeader_e_shstrndx_Offset);
// Set the NameIdx of each section in the string table and emit the bytes for
// the string table.
unsigned Index = 0;
+ DataBuffer &Buf = SHStrTab.SectionData;
- for (unsigned i = 0, e = SectionList.size(); i != e; ++i) {
+ for (std::list<ELFSection>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I) {
// Set the index into the table. Note if we have lots of entries with
// common suffixes, we could memoize them here if we cared.
- SectionList[i].NameIdx = Index;
+ I->NameIdx = Index;
// Add the name to the output buffer, including the null terminator.
- OutputBuffer.insert(OutputBuffer.end(), SectionList[i].Name.begin(),
- SectionList[i].Name.end());
+ Buf.insert(Buf.end(), I->Name.begin(), I->Name.end());
+
// Add a null terminator.
- OutputBuffer.push_back(0);
+ Buf.push_back(0);
// Keep track of the number of bytes emitted to this section.
- Index += SectionList[i].Name.size()+1;
+ Index += I->Name.size()+1;
}
// Set the size of .shstrtab now that we know what it is.
- SectionList.back().Size = Index;
+ assert(Index == Buf.size());
+ SHStrTab.Size = Index;
}
-/// EmitSectionTable - Now that we have emitted the entire contents of the file
-/// (all of the sections), emit the section table which informs the reader where
-/// the boundaries are.
-void ELFWriter::EmitSectionTable() {
- // Now that all of the sections have been emitted, set the e_shnum entry in
- // the ELF header.
- fixhalf(SectionList.size(), ELFHeader_e_shnum_Offset);
+/// OutputSectionsAndSectionTable - Now that we have constructed the file header
+/// and all of the sections, emit these to the ostream destination and emit the
+/// SectionTable.
+void ELFWriter::OutputSectionsAndSectionTable() {
+ // Pass #1: Compute the file offset for each section.
+ size_t FileOff = FileHeader.size(); // File header first.
+
+ // Emit all of the section data in order.
+ for (std::list<ELFSection>::iterator I = SectionList.begin(),
+ E = SectionList.end(); I != E; ++I) {
+ // Align FileOff to whatever the alignment restrictions of the section are.
+ if (I->Align)
+ FileOff = (FileOff+I->Align-1) & ~(I->Align-1);
+ I->Offset = FileOff;
+ FileOff += I->SectionData.size();
+ }
+
+ // Align Section Header.
+ unsigned TableAlign = is64Bit ? 8 : 4;
+ FileOff = (FileOff+TableAlign-1) & ~(TableAlign-1);
+
+ // Now that we know where all of the sections will be emitted, set the e_shnum
+ // entry in the ELF header.
+ fixhalf(FileHeader, NumSections, ELFHeader_e_shnum_Offset);
- // Now that we know the offset in the file of the section table (which we emit
- // next), update the e_shoff address in the ELF header.
- fixaddr(OutputBuffer.size(), ELFHeader_e_shoff_Offset);
+ // Now that we know the offset in the file of the section table, update the
+ // e_shoff address in the ELF header.
+ fixaddr(FileHeader, FileOff, ELFHeader_e_shoff_Offset);
- // Emit all of the section table entries.
- for (unsigned i = 0, e = SectionList.size(); i != e; ++i) {
- const ELFSection &S = SectionList[i];
- outword(S.NameIdx); // sh_name - Symbol table name idx
- outword(S.Type); // sh_type - Section contents & semantics
- outword(S.Flags); // sh_flags - Section flags.
- outaddr(S.Addr); // sh_addr - The mem address this section appears in.
- outaddr(S.Offset); // sh_offset - The offset from the start of the file.
- outword(S.Size); // sh_size - The section size.
- outword(S.Link); // sh_link - Section header table index link.
- outword(S.Info); // sh_info - Auxillary information.
- outword(S.Align); // sh_addralign - Alignment of section.
- outword(S.EntSize); // sh_entsize - Size of each entry in the section.
+ // Now that we know all of the data in the file header, emit it and all of the
+ // sections!
+ O.write((char*)&FileHeader[0], FileHeader.size());
+ FileOff = FileHeader.size();
+ DataBuffer().swap(FileHeader);
+
+ DataBuffer Table;
+
+ // Emit all of the section data and build the section table itself.
+ while (!SectionList.empty()) {
+ const ELFSection &S = *SectionList.begin();
+
+ // Align FileOff to whatever the alignment restrictions of the section are.
+ if (S.Align)
+ for (size_t NewFileOff = (FileOff+S.Align-1) & ~(S.Align-1);
+ FileOff != NewFileOff; ++FileOff)
+ O.put(0xAB);
+ O.write((char*)&S.SectionData[0], S.SectionData.size());
+ FileOff += S.SectionData.size();
+
+ outword(Table, S.NameIdx); // sh_name - Symbol table name idx
+ outword(Table, S.Type); // sh_type - Section contents & semantics
+ outword(Table, S.Flags); // sh_flags - Section flags.
+ outaddr(Table, S.Addr); // sh_addr - The mem addr this section is in.
+ outaddr(Table, S.Offset); // sh_offset - Offset from the file start.
+ outword(Table, S.Size); // sh_size - The section size.
+ outword(Table, S.Link); // sh_link - Section header table index link.
+ outword(Table, S.Info); // sh_info - Auxillary information.
+ outword(Table, S.Align); // sh_addralign - Alignment of section.
+ outword(Table, S.EntSize); // sh_entsize - Size of entries in the section.
+
+ SectionList.pop_front();
}
- // Release the memory allocated for the section list.
- std::vector<ELFSection>().swap(SectionList);
+ // Align output for the section table.
+ for (size_t NewFileOff = (FileOff+TableAlign-1) & ~(TableAlign-1);
+ FileOff != NewFileOff; ++FileOff)
+ O.put(0xAB);
+
+ // Emit the section table itself.
+ O.write((char*)&Table[0], Table.size());
}
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