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-rw-r--r--lib/CodeGen/ELFWriter.cpp310
1 files changed, 167 insertions, 143 deletions
diff --git a/lib/CodeGen/ELFWriter.cpp b/lib/CodeGen/ELFWriter.cpp
index cc8895df09..c9d1ae4041 100644
--- a/lib/CodeGen/ELFWriter.cpp
+++ b/lib/CodeGen/ELFWriter.cpp
@@ -49,10 +49,11 @@ namespace llvm {
/// 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);
@@ -62,7 +63,7 @@ namespace llvm {
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");
@@ -71,10 +72,10 @@ namespace llvm {
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!");
@@ -102,21 +103,22 @@ namespace llvm {
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
@@ -141,12 +143,13 @@ void ELFCodeEmitter::finishFunction(MachineFunction &F) {
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);
@@ -165,6 +168,7 @@ ELFWriter::ELFWriter(std::ostream &o, TargetMachine &tm) : O(o), TM(tm) {
// Create the machine code emitter object for this target.
MCE = new ELFCodeEmitter(*this);
+ NumSections = 0;
}
ELFWriter::~ELFWriter() {
@@ -176,47 +180,47 @@ 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;
}
@@ -286,7 +290,7 @@ void ELFWriter::EmitGlobal(GlobalVariable *GV, ELFSection &DataSection,
}
// 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.
@@ -310,40 +314,19 @@ bool ELFWriter::runOnMachineFunction(MachineFunction &MF) {
/// 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();
@@ -353,14 +336,12 @@ bool ELFWriter::doFinalization(Module &M) {
// 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;
@@ -375,13 +356,14 @@ void ELFWriter::EmitSymbolTable() {
// 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) {
@@ -394,53 +376,51 @@ void ELFWriter::EmitSymbolTable() {
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
@@ -448,63 +428,107 @@ void ELFWriter::EmitSymbolTable() {
/// 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());
}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-05-01 05:18:50 +0000