//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file was developed by Chris Lattner and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
#define LLVM_CODEGEN_ELFWRITER_H
#include "llvm/CodeGen/MachineFunctionPass.h"
+#include <list>
namespace llvm {
class GlobalVariable;
+ class Mangler;
+ class MachineCodeEmitter;
+ class ELFCodeEmitter;
/// ELFWriter - This class implements the common target-independent code for
/// writing ELF files. Targets should derive a class from this to
/// parameterize the output format.
///
class ELFWriter : public MachineFunctionPass {
+ friend class ELFCodeEmitter;
+ public:
+ MachineCodeEmitter &getMachineCodeEmitter() const {
+ return *(MachineCodeEmitter*)MCE;
+ }
+
+ ~ELFWriter();
+
+ typedef std::vector<unsigned char> DataBuffer;
+
protected:
ELFWriter(std::ostream &O, TargetMachine &TM);
///
TargetMachine &TM;
+ /// Mang - The object used to perform name mangling for this module.
+ ///
+ Mangler *Mang;
+
+ /// MCE - The MachineCodeEmitter object that we are exposing to emit machine
+ /// code for functions to the .o file.
+ ELFCodeEmitter *MCE;
+
//===------------------------------------------------------------------===//
// Properties to be set by the derived class ctor, used to configure the
// ELFWriter.
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 Info;
unsigned Align;
unsigned EntSize;
- ELFSection() : Type(0), Flags(0), Addr(0), Offset(0), Size(0), Link(0),
- Info(0), Align(0), EntSize(0) {
- }
- ELFSection(const char *name, unsigned offset)
- : Name(name), Type(0), Flags(0), Addr(0), Offset(offset), Size(0),
+
+ /// 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 };
+ enum { SHN_UNDEF = 0, SHN_ABS = 0xFFF1, SHN_COMMON = 0xFFF2 };
+ enum { // SHF - ELF Section Header Flags
+ SHF_WRITE = 1 << 0, // Writable
+ SHF_ALLOC = 1 << 1, // Mapped into the process addr space
+ SHF_EXECINSTR = 1 << 2, // Executable
+ SHF_MERGE = 1 << 4, // Might be merged if equal
+ SHF_STRINGS = 1 << 5, // Contains null-terminated strings
+ SHF_INFO_LINK = 1 << 6, // 'sh_info' contains SHT index
+ SHF_LINK_ORDER = 1 << 7, // Preserve order after combining
+ SHF_OS_NONCONFORMING = 1 << 8, // nonstandard OS support required
+ SHF_GROUP = 1 << 9, // Section is a member of a group
+ SHF_TLS = 1 << 10 // Section holds thread-local data
+ };
+
+ 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;
-
- // 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.
- 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.
-
- void outbyte(unsigned char X) { OutputBuffer.push_back(X); }
- void outhalf(unsigned short X) {
- if (isLittleEndian) {
- OutputBuffer.push_back(X&255);
- OutputBuffer.push_back(X >> 8);
- } else {
- OutputBuffer.push_back(X >> 8);
- OutputBuffer.push_back(X&255);
- }
- }
- void outword(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);
- } 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);
- }
- }
- void outaddr(uint64_t X) {
- if (!is64Bit)
- outword((unsigned)X);
- else
- assert(0 && "Emission of 64-bit data not implemented yet!");
+ 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,
+ unsigned Type, unsigned Flags = 0) {
+ ELFSection *&SN = SectionLookup[Name];
+ if (SN) return *SN;
+
+ SectionList.push_back(Name);
+ SN = &SectionList.back();
+ SN->SectionIdx = NumSections++;
+ SN->Type = Type;
+ SN->Flags = Flags;
+ return *SN;
}
- // fix functions - Replace an existing entry at an offset.
- void fixhalf(unsigned short X, unsigned Offset) {
- unsigned char *P = &OutputBuffer[Offset];
- P[0] = (X >> (isLittleEndian ? 0 : 8)) & 255;
- P[1] = (X >> (isLittleEndian ? 8 : 0)) & 255;
+ ELFSection &getDataSection() {
+ return getSection(".data", ELFSection::SHT_PROGBITS,
+ ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC);
}
-
- void fixword(unsigned X, unsigned Offset) {
- unsigned char *P = &OutputBuffer[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;
+ ELFSection &getBSSSection() {
+ return getSection(".bss", ELFSection::SHT_NOBITS,
+ ELFSection::SHF_WRITE | ELFSection::SHF_ALLOC);
}
- void fixaddr(uint64_t X, unsigned Offset) {
- if (!is64Bit)
- fixword((unsigned)X, Offset);
- else
- assert(0 && "Emission of 64-bit data not implemented yet!");
- }
+ /// ELFSym - This struct contains information about each symbol that is
+ /// added to logical symbol table for the module. This is eventually
+ /// turned into a real symbol table in the file.
+ struct ELFSym {
+ const GlobalValue *GV; // The global value this corresponds to.
+ unsigned NameIdx; // Index in .strtab of name, once emitted.
+ uint64_t Value;
+ unsigned Size;
+ unsigned char Info;
+ unsigned char Other;
+ unsigned short SectionIdx;
+
+ enum { STB_LOCAL = 0, STB_GLOBAL = 1, STB_WEAK = 2 };
+ enum { STT_NOTYPE = 0, STT_OBJECT = 1, STT_FUNC = 2, STT_SECTION = 3,
+ STT_FILE = 4 };
+ ELFSym(const GlobalValue *gv) : GV(gv), Value(0), Size(0), Info(0),
+ Other(0), SectionIdx(0) {}
+
+ void SetBind(unsigned X) {
+ assert(X == (X & 0xF) && "Bind value out of range!");
+ Info = (Info & 0x0F) | (X << 4);
+ }
+ void SetType(unsigned X) {
+ assert(X == (X & 0xF) && "Type value out of range!");
+ Info = (Info & 0xF0) | X;
+ }
+ };
+ /// SymbolTable - This is the list of symbols we have emitted to the file.
+ /// This actually gets rearranged before emission to the file (to put the
+ /// local symbols first in the list).
+ std::vector<ELFSym> SymbolTable;
+
+ // 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.
private:
- void EmitDATASectionGlobal(GlobalVariable *GV);
- void EmitBSSSectionGlobal(GlobalVariable *GV);
void EmitGlobal(GlobalVariable *GV);
+ void EmitSymbolTable();
+
void EmitSectionTableStringTable();
- void EmitSectionTable();
+ void OutputSectionsAndSectionTable();
};
}
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