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elfobj.c
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elfobj.c
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// Copyright (C) ?-1998 by Symantec
// Copyright (C) 2000-2010 by Digital Mars
// All Rights Reserved
// http://www.digitalmars.com
/*
* This source file is made available for personal use
* only. The license is in backendlicense.txt
* For any other uses, please contact Digital Mars.
*/
// Output to ELF object files
#if SCPP || MARS
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#if __sun
#include <alloca.h>
#endif
#include "cc.h"
#include "global.h"
#include "code.h"
#include "type.h"
#include "melf.h"
#include "outbuf.h"
#include "filespec.h"
#include "cv4.h"
#include "cgcv.h"
#include "dt.h"
#include "aa.h"
#include "tinfo.h"
#if ELFOBJ
#include "dwarf.h"
#include "aa.h"
#include "tinfo.h"
//#define DEBSYM 0x7E
static Outbuffer *fobjbuf;
static char __file__[] = __FILE__; // for tassert.h
#include "tassert.h"
#define MATCH_SECTION 1
#define DEST_LEN (IDMAX + IDOHD + 1)
char *obj_mangle2(Symbol *s,char *dest);
#if MARS
// C++ name mangling is handled by front end
#define cpp_mangle(s) ((s)->Sident)
#endif
/**
* If set the compiler requires full druntime support of the new
* section registration and will no longer create global bracket
* symbols (_deh_beg,_deh_end,_tlsstart,_tlsend).
*/
#define REQUIRE_DSO_REGISTRY (DMDV2 && TARGET_LINUX)
/***************************************************
* Correspondence of relocation types
* 386 32 bit in 64 64 in 64
* RI_TYPE_SYM32 R_X86_64_32 R_X86_64_64
* RI_TYPE_GOTOFF R_X86_64_PC32 R_X86_64_
* RI_TYPE_GOTPC R_X86_64_ R_X86_64_
* RI_TYPE_GOT32 R_X86_64_ R_X86_64_
* RI_TYPE_TLS_GD R_X86_64_TLSGD R_X86_64_
* RI_TYPE_TLS_IE R_X86_64_GOTTPOFF R_X86_64_
* RI_TYPE_TLS_LE R_X86_64_TPOFF32 R_X86_64_
* RI_TYPE_PLT32 R_X86_64_PLT32 R_X86_64_
* RI_TYPE_PC32 R_X86_64_PC32 R_X86_64_
*/
/******************************************
*/
symbol *GOTsym; // global offset table reference
symbol *Obj::getGOTsym()
{
if (!GOTsym)
{
GOTsym = symbol_name("_GLOBAL_OFFSET_TABLE_",SCglobal,tspvoid);
}
return GOTsym;
}
void Obj::refGOTsym()
{
if (!GOTsym)
{
symbol *s = Obj::getGOTsym();
Obj::external(s);
}
}
static void objfile_write(FILE *fd, void *buffer, unsigned len);
STATIC char * objmodtoseg (const char *modname);
STATIC void objfixupp (struct FIXUP *);
STATIC void ledata_new (int seg,targ_size_t offset);
void obj_tlssections();
#if MARS
static void obj_rtinit();
#endif
static IDXSYM elf_addsym(IDXSTR sym, targ_size_t val, unsigned sz,
unsigned typ,unsigned bind,IDXSEC sec);
static long elf_align(targ_size_t size, long offset);
// The object file is built is several separate pieces
// Non-repeatable section types have single output buffers
// Pre-allocated buffers are defined for:
// Section Names string table
// Section Headers table
// Symbol table
// String table
// Notes section
// Comment data
// Section Names - String table for section names only
static Outbuffer *section_names;
#define SEC_NAMES_INIT 800
#define SEC_NAMES_INC 400
// Hash table for section_names
AArray *section_names_hashtable;
/* ====================== Cached Strings in section_names ================= */
struct TypeInfo_Idxstr : TypeInfo
{
const char* toString();
hash_t getHash(void *p);
int equals(void *p1, void *p2);
int compare(void *p1, void *p2);
size_t tsize();
void swap(void *p1, void *p2);
};
TypeInfo_Idxstr ti_idxstr;
const char* TypeInfo_Idxstr::toString()
{
return "IDXSTR";
}
hash_t TypeInfo_Idxstr::getHash(void *p)
{
IDXSTR a = *(IDXSTR *)p;
hash_t hash = 0;
for (const char *s = (char *)(section_names->buf + a);
*s;
s++)
{
hash = hash * 11 + *s;
}
return hash;
}
int TypeInfo_Idxstr::equals(void *p1, void *p2)
{
IDXSTR a1 = *(IDXSTR*)p1;
IDXSTR a2 = *(IDXSTR*)p2;
const char *s1 = (char *)(section_names->buf + a1);
const char *s2 = (char *)(section_names->buf + a2);
return strcmp(s1, s2) == 0;
}
int TypeInfo_Idxstr::compare(void *p1, void *p2)
{
IDXSTR a1 = *(IDXSTR*)p1;
IDXSTR a2 = *(IDXSTR*)p2;
const char *s1 = (char *)(section_names->buf + a1);
const char *s2 = (char *)(section_names->buf + a2);
return strcmp(s1, s2);
}
size_t TypeInfo_Idxstr::tsize()
{
return sizeof(IDXSTR);
}
void TypeInfo_Idxstr::swap(void *p1, void *p2)
{
assert(0);
}
/* ======================================================================== */
// String Table - String table for all other names
static Outbuffer *symtab_strings;
// Section Headers
Outbuffer *SECbuf; // Buffer to build section table in
#define SecHdrTab ((Elf32_Shdr *)SECbuf->buf)
#define GET_SECTION(secidx) (SecHdrTab + secidx)
#define GET_SECTION_NAME(secidx) (section_names->buf + SecHdrTab[secidx].sh_name)
// The relocation for text and data seems to get lost.
// Try matching the order gcc output them
// This means defining the sections and then removing them if they are
// not used.
static int section_cnt; // Number of sections in table
#define SHN_TEXT 1
#define SHN_RELTEXT 2
#define SHN_DATA 3
#define SHN_RELDATA 4
#define SHN_BSS 5
#define SHN_RODAT 6
#define SHN_STRINGS 7
#define SHN_SYMTAB 8
#define SHN_SECNAMES 9
#define SHN_COM 10
#define SHN_NOTE 11
#define SHN_GNUSTACK 12
#define SHN_CDATAREL 13
IDXSYM *mapsec2sym;
#define S2S_INC 20
#define SymbolTable ((Elf32_Sym *)SYMbuf->buf)
#define SymbolTable64 ((Elf64_Sym *)SYMbuf->buf)
static int symbol_idx; // Number of symbols in symbol table
static int local_cnt; // Number of symbols with STB_LOCAL
#define STI_FILE 1 // Where file symbol table entry is
#define STI_TEXT 2
#define STI_DATA 3
#define STI_BSS 4
#define STI_GCC 5 // Where "gcc2_compiled" symbol is */
#define STI_RODAT 6 // Symbol for readonly data
#define STI_NOTE 7 // Where note symbol table entry is
#define STI_COM 8
#define STI_CDATAREL 9 // Symbol for readonly data with relocations
// NOTE: There seems to be a requirement that the read-only data have the
// same symbol table index and section index. Use section NOTE as a place
// holder. When a read-only string section is required, swap to NOTE.
// Symbol Table
Outbuffer *SYMbuf; // Buffer to build symbol table in
// Extended section header indices
static Outbuffer *shndx_data;
static const IDXSEC secidx_shndx = SHN_HIRESERVE + 1;
// Notes data (note currently used)
static Outbuffer *note_data;
static IDXSEC secidx_note; // Final table index for note data
// Comment data for compiler version
static Outbuffer *comment_data;
static const char compiler[] = "\0Digital Mars C/C++"
VERSION
; // compiled by ...
// Each compiler segment is an elf section
// Predefined compiler segments CODE,DATA,CDATA,UDATA map to indexes
// into SegData[]
// An additionl index is reserved for comment data
// New compiler segments are added to end.
//
// There doesn't seem to be any way to get reserved data space in the
// same section as initialized data or code, so section offsets should
// be continuous when adding data. Fix-ups anywhere withing existing data.
#define COMD CDATAREL+1
#define OB_SEG_SIZ 10 // initial number of segments supported
#define OB_SEG_INC 10 // increment for additional segments
#define OB_CODE_STR 100000 // initial size for code
#define OB_CODE_INC 100000 // increment for additional code
#define OB_DATA_STR 100000 // initial size for data
#define OB_DATA_INC 100000 // increment for additional data
#define OB_CDATA_STR 1024 // initial size for data
#define OB_CDATA_INC 1024 // increment for additional data
#define OB_COMD_STR 256 // initial size for comments
// increment as needed
#define OB_XTRA_STR 250 // initial size for extra segments
#define OB_XTRA_INC 10000 // increment size
#define MAP_SEG2SECIDX(seg) (SegData[seg]->SDshtidx)
#define MAP_SEG2SYMIDX(seg) (SegData[seg]->SDsymidx)
#define MAP_SEG2SEC(seg) (&SecHdrTab[MAP_SEG2SECIDX(seg)])
#define MAP_SEG2TYP(seg) (MAP_SEG2SEC(seg)->sh_flags & SHF_EXECINSTR ? CODE : DATA)
seg_data **SegData;
int seg_count;
int seg_max;
int seg_tlsseg = UNKNOWN;
int seg_tlsseg_bss = UNKNOWN;
int elf_getsegment2(IDXSEC shtidx, IDXSYM symidx, IDXSEC relidx);
/*******************************
* Output a string into a string table
* Input:
* strtab = string table for entry
* str = string to add
*
* Returns index into the specified string table.
*/
IDXSTR Obj::addstr(Outbuffer *strtab, const char *str)
{
//dbg_printf("Obj::addstr(strtab = x%x str = '%s')\n",strtab,str);
IDXSTR idx = strtab->size(); // remember starting offset
strtab->writeString(str);
//dbg_printf("\tidx %d, new size %d\n",idx,strtab->size());
return idx;
}
/*******************************
* Find a string in a string table
* Input:
* strtab = string table for entry
* str = string to find
*
* Returns index into the specified string table or 0.
*/
static IDXSTR elf_findstr(Outbuffer *strtab, const char *str, const char *suffix)
{
//printf("elf_findstr(strtab = %p, str = %s, suffix = %s\n", strtab, str ? str : "", suffix ? suffix : "");
size_t len = strlen(str);
// Combine str~suffix and have buf point to the combination
#ifdef DEBUG
char tmpbuf[25]; // to exercise the alloca() code path
#else
char tmpbuf[1024]; // the alloca() code path is slow
#endif
const char *buf;
if (suffix)
{
size_t suffixlen = strlen(suffix);
if (len + suffixlen >= sizeof(tmpbuf))
{
buf = (char *)alloca(len + suffixlen + 1);
assert(buf);
}
else
{
buf = tmpbuf;
}
memcpy((char *)buf, str, len);
memcpy((char *)buf + len, suffix, suffixlen + 1);
len += suffixlen;
}
else
buf = str;
// Linear search, slow
const char *ent = (char *)strtab->buf+1;
const char *pend = ent+strtab->size() - 1;
while (ent + len < pend)
{
if (memcmp(buf, ent, len + 1) == 0)
return ent - (const char *)strtab->buf;
ent = (const char *)memchr(ent, 0, pend - ent);
ent += 1;
}
return 0; // never found match
}
/*******************************
* Output a mangled string into the symbol string table
* Input:
* str = string to add
*
* Returns index into the table.
*/
static IDXSTR elf_addmangled(Symbol *s)
{
//printf("elf_addmangled(%s)\n", s->Sident);
char dest[DEST_LEN];
char *destr;
const char *name;
int len;
IDXSTR namidx;
namidx = symtab_strings->size();
destr = obj_mangle2(s, dest);
name = destr;
if (CPP && name[0] == '_' && name[1] == '_')
{
if (strncmp(name,"__ct__",6) == 0)
name += 4;
#if 0
switch(name[2])
{
case 'c':
if (strncmp(name,"__ct__",6) == 0)
name += 4;
break;
case 'd':
if (strcmp(name,"__dl__FvP") == 0)
name = "__builtin_delete";
break;
case 'v':
//if (strcmp(name,"__vec_delete__FvPiUIPi") == 0)
//name = "__builtin_vec_del";
//else
//if (strcmp(name,"__vn__FPUI") == 0)
//name = "__builtin_vec_new";
break;
case 'n':
if (strcmp(name,"__nw__FPUI") == 0)
name = "__builtin_new";
break;
}
#endif
}
else if (tyfunc(s->ty()) && s->Sfunc && s->Sfunc->Fredirect)
name = s->Sfunc->Fredirect;
len = strlen(name);
symtab_strings->reserve(len+1);
strcpy((char *)symtab_strings->p,name);
symtab_strings->setsize(namidx+len+1);
if (destr != dest) // if we resized result
mem_free(destr);
//dbg_printf("\telf_addmagled symtab_strings %s namidx %d len %d size %d\n",name, namidx,len,symtab_strings->size());
return namidx;
}
/*******************************
* Output a symbol into the symbol table
* Input:
* stridx = string table index for name
* val = value associated with symbol
* sz = symbol size
* typ = symbol type
* bind = symbol binding
* segidx = segment index for segment where symbol is defined
*
* Returns the symbol table index for the symbol
*/
static IDXSYM elf_addsym(IDXSTR nam, targ_size_t val, unsigned sz,
unsigned typ, unsigned bind, IDXSEC sec)
{
//dbg_printf("elf_addsym(nam %d, val %d, sz %x, typ %x, bind %x, sec %d\n",
//nam,val,sz,typ,bind,sec);
/* We want globally defined data symbols to have a size because
* zero sized symbols break copy relocations for shared libraries.
*/
if(sz == 0 && (bind == STB_GLOBAL || bind == STB_WEAK) &&
(typ == STT_OBJECT || typ == STT_TLS) &&
sec != SHN_UNDEF)
sz = 1; // so fake it if it doesn't
if (sec > SHN_HIRESERVE)
{ // If the section index is too big we need to store it as
// extended section header index.
if (!shndx_data)
shndx_data = new Outbuffer(50 * sizeof(Elf64_Word));
// fill with zeros up to symbol_idx
const size_t shndx_idx = shndx_data->size() / sizeof(Elf64_Word);
shndx_data->writezeros((symbol_idx - shndx_idx) * sizeof(Elf64_Word));
shndx_data->write32(sec);
sec = SHN_XINDEX;
}
if (I64)
{
if (!SYMbuf)
{ SYMbuf = new Outbuffer(50 * sizeof(Elf64_Sym));
SYMbuf->reserve(100 * sizeof(Elf64_Sym));
}
Elf64_Sym sym;
sym.st_name = nam;
sym.st_value = val;
sym.st_size = sz;
sym.st_info = ELF_ST_INFO(bind,typ);
sym.st_other = 0;
sym.st_shndx = sec;
SYMbuf->write(&sym,sizeof(sym));
}
else
{
if (!SYMbuf)
{ SYMbuf = new Outbuffer(50 * sizeof(Elf32_Sym));
SYMbuf->reserve(100 * sizeof(Elf32_Sym));
}
Elf32_Sym sym;
sym.st_name = nam;
sym.st_value = val;
sym.st_size = sz;
sym.st_info = ELF_ST_INFO(bind,typ);
sym.st_other = 0;
sym.st_shndx = sec;
SYMbuf->write(&sym,sizeof(sym));
}
if (bind == STB_LOCAL)
local_cnt++;
//dbg_printf("\treturning symbol table index %d\n",symbol_idx);
return symbol_idx++;
}
/*******************************
* Create a new section header table entry.
*
* Input:
* name = section name
* suffix = suffix for name or NULL
* type = type of data in section sh_type
* flags = attribute flags sh_flags
* Output:
* section_cnt = assigned number for this section
* Note: Sections will be reordered on output
*/
static IDXSEC elf_newsection2(
elf_u32_f32 name,
elf_u32_f32 type,
elf_u32_f32 flags,
elf_add_f32 addr,
elf_off_f32 offset,
elf_u32_f32 size,
elf_u32_f32 link,
elf_u32_f32 info,
elf_u32_f32 addralign,
elf_u32_f32 entsize)
{
Elf32_Shdr sec;
sec.sh_name = name;
sec.sh_type = type;
sec.sh_flags = flags;
sec.sh_addr = addr;
sec.sh_offset = offset;
sec.sh_size = size;
sec.sh_link = link;
sec.sh_info = info;
sec.sh_addralign = addralign;
sec.sh_entsize = entsize;
if (!SECbuf)
{ SECbuf = new Outbuffer(4 * sizeof(Elf32_Shdr));
SECbuf->reserve(16 * sizeof(Elf32_Shdr));
}
if (section_cnt == SHN_LORESERVE)
{ // insert dummy null sections to skip reserved section indices
section_cnt = SHN_HIRESERVE + 1;
SECbuf->writezeros((SHN_HIRESERVE + 1 - SHN_LORESERVE) * sizeof(sec));
// shndx itself becomes the first section with an extended index
IDXSTR namidx = Obj::addstr(section_names, ".symtab_shndx");
elf_newsection2(namidx,SHT_SYMTAB_SHNDX,0,0,0,0,SHN_SYMTAB,0,4,4);
}
SECbuf->write((void *)&sec, sizeof(sec));
return section_cnt++;
}
static IDXSEC elf_newsection(const char *name, const char *suffix,
elf_u32_f32 type, elf_u32_f32 flags)
{
// dbg_printf("elf_newsection(%s,%s,type %d, flags x%x)\n",
// name?name:"",suffix?suffix:"",type,flags);
IDXSTR namidx = section_names->size();
section_names->writeString(name);
if (suffix)
{ // Append suffix string
section_names->setsize(section_names->size() - 1); // back up over terminating 0
section_names->writeString(suffix);
}
IDXSTR *pidx = (IDXSTR *)section_names_hashtable->get(&namidx);
assert(!*pidx); // must not already exist
*pidx = namidx;
return elf_newsection2(namidx,type,flags,0,0,0,0,0,0,0);
}
/**************************
* Ouput read only data and generate a symbol for it.
*
*/
symbol *Obj::sym_cdata(tym_t ty,char *p,int len)
{
symbol *s;
#if 0
if (OPT_IS_SET(OPTfwritable_strings))
{
alignOffset(DATA, tysize(ty));
s = symboldata(Doffset, ty);
SegData[DATA]->SDbuf->write(p,len);
s->Sseg = DATA;
s->Soffset = Doffset; // Remember its offset into DATA section
Doffset += len;
}
else
#endif
{
//printf("Obj::sym_cdata(ty = %x, p = %x, len = %d, CDoffset = %x)\n", ty, p, len, CDoffset);
alignOffset(CDATA, tysize(ty));
s = symboldata(CDoffset, ty);
Obj::bytes(CDATA, CDoffset, len, p);
s->Sseg = CDATA;
}
s->Sfl = /*(config.flags3 & CFG3pic) ? FLgotoff :*/ FLextern;
return s;
}
/**************************
* Ouput read only data for data.
* Output:
* *pseg segment of that data
* Returns:
* offset of that data
*/
int Obj::data_readonly(char *p, int len, int *pseg)
{
int oldoff;
/*if (OPT_IS_SET(OPTfwritable_strings))
{
oldoff = Doffset;
SegData[DATA]->SDbuf->reserve(len);
SegData[DATA]->SDbuf->writen(p,len);
Doffset += len;
*pseg = DATA;
}
else*/
{
oldoff = CDoffset;
SegData[CDATA]->SDbuf->reserve(len);
SegData[CDATA]->SDbuf->writen(p,len);
CDoffset += len;
*pseg = CDATA;
}
return oldoff;
}
int Obj::data_readonly(char *p, int len)
{
int pseg;
return Obj::data_readonly(p, len, &pseg);
}
/******************************
* Perform initialization that applies to all .o output files.
* Called before any other obj_xxx routines
*/
Obj *Obj::init(Outbuffer *objbuf, const char *filename, const char *csegname)
{
//printf("Obj::init()\n");
ElfObj *obj = new ElfObj();
cseg = CODE;
fobjbuf = objbuf;
mapsec2sym = NULL;
note_data = NULL;
secidx_note = 0;
comment_data = NULL;
seg_tlsseg = UNKNOWN;
seg_tlsseg_bss = UNKNOWN;
GOTsym = NULL;
// Initialize buffers
if (symtab_strings)
symtab_strings->setsize(1);
else
{ symtab_strings = new Outbuffer(1024);
symtab_strings->reserve(2048);
symtab_strings->writeByte(0);
}
if (SECbuf)
SECbuf->setsize(0);
section_cnt = 0;
if (I64)
{
static char section_names_init64[] =
"\0.symtab\0.strtab\0.shstrtab\0.text\0.data\0.bss\0.note\0.comment\0.rodata\0.note.GNU-stack\0.data.rel.ro\0.rela.text\0.rela.data";
#define NAMIDX_NONE 0
#define NAMIDX_SYMTAB 1 // .symtab
#define NAMIDX_STRTAB 9 // .strtab
#define NAMIDX_SHSTRTAB 17 // .shstrtab
#define NAMIDX_TEXT 27 // .text
#define NAMIDX_DATA 33 // .data
#define NAMIDX_BSS 39 // .bss
#define NAMIDX_NOTE 44 // .note
#define NAMIDX_COMMENT 50 // .comment
#define NAMIDX_RODATA 59 // .rodata
#define NAMIDX_GNUSTACK 67 // .note.GNU-stack
#define NAMIDX_CDATAREL 83 // .data.rel.ro
#define NAMIDX_RELTEXT 96 // .rel.text and .rela.text
#define NAMIDX_RELDATA 106 // .rel.data
#define NAMIDX_RELDATA64 107 // .rela.data
if (section_names)
section_names->setsize(sizeof(section_names_init64));
else
{ section_names = new Outbuffer(512);
section_names->reserve(1024);
section_names->writen(section_names_init64, sizeof(section_names_init64));
}
if (section_names_hashtable)
delete section_names_hashtable;
section_names_hashtable = new AArray(&ti_idxstr, sizeof(IDXSTR));
// name,type,flags,addr,offset,size,link,info,addralign,entsize
elf_newsection2(0, SHT_NULL, 0, 0,0,0,0,0, 0,0);
elf_newsection2(NAMIDX_TEXT,SHT_PROGDEF,SHF_ALLOC|SHF_EXECINSTR,0,0,0,0,0, 4,0);
elf_newsection2(NAMIDX_RELTEXT,SHT_RELA, 0,0,0,0,SHN_SYMTAB, SHN_TEXT, 8,0x18);
elf_newsection2(NAMIDX_DATA,SHT_PROGDEF,SHF_ALLOC|SHF_WRITE, 0,0,0,0,0, 8,0);
elf_newsection2(NAMIDX_RELDATA64,SHT_RELA, 0,0,0,0,SHN_SYMTAB, SHN_DATA, 8,0x18);
elf_newsection2(NAMIDX_BSS, SHT_NOBITS,SHF_ALLOC|SHF_WRITE, 0,0,0,0,0, 16,0);
elf_newsection2(NAMIDX_RODATA,SHT_PROGDEF,SHF_ALLOC, 0,0,0,0,0, 16,0);
elf_newsection2(NAMIDX_STRTAB,SHT_STRTAB, 0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_SYMTAB,SHT_SYMTAB, 0, 0,0,0,0,0, 8,0);
elf_newsection2(NAMIDX_SHSTRTAB,SHT_STRTAB, 0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_COMMENT, SHT_PROGDEF,0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_NOTE,SHT_NOTE, 0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_GNUSTACK,SHT_PROGDEF,0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_CDATAREL,SHT_PROGDEF,SHF_ALLOC|SHF_WRITE,0,0,0,0,0, 16,0);
IDXSTR namidx;
namidx = NAMIDX_TEXT; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_RELTEXT; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_DATA; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_RELDATA64; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_BSS; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_RODATA; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_STRTAB; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_SYMTAB; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_SHSTRTAB; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_COMMENT; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_NOTE; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_GNUSTACK; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_CDATAREL; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
}
else
{
static char section_names_init[] =
"\0.symtab\0.strtab\0.shstrtab\0.text\0.data\0.bss\0.note\0.comment\0.rodata\0.note.GNU-stack\0.data.rel.ro\0.rel.text\0.rel.data";
if (section_names)
section_names->setsize(sizeof(section_names_init));
else
{ section_names = new Outbuffer(512);
section_names->reserve(100*1024);
section_names->writen(section_names_init, sizeof(section_names_init));
}
if (section_names_hashtable)
delete section_names_hashtable;
section_names_hashtable = new AArray(&ti_idxstr, sizeof(IDXSTR));
// name,type,flags,addr,offset,size,link,info,addralign,entsize
elf_newsection2(0, SHT_NULL, 0, 0,0,0,0,0, 0,0);
elf_newsection2(NAMIDX_TEXT,SHT_PROGDEF,SHF_ALLOC|SHF_EXECINSTR,0,0,0,0,0, 16,0);
elf_newsection2(NAMIDX_RELTEXT,SHT_REL, 0,0,0,0,SHN_SYMTAB, SHN_TEXT, 4,8);
elf_newsection2(NAMIDX_DATA,SHT_PROGDEF,SHF_ALLOC|SHF_WRITE, 0,0,0,0,0, 4,0);
elf_newsection2(NAMIDX_RELDATA,SHT_REL, 0,0,0,0,SHN_SYMTAB, SHN_DATA, 4,8);
elf_newsection2(NAMIDX_BSS, SHT_NOBITS,SHF_ALLOC|SHF_WRITE, 0,0,0,0,0, 32,0);
elf_newsection2(NAMIDX_RODATA,SHT_PROGDEF,SHF_ALLOC, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_STRTAB,SHT_STRTAB, 0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_SYMTAB,SHT_SYMTAB, 0, 0,0,0,0,0, 4,0);
elf_newsection2(NAMIDX_SHSTRTAB,SHT_STRTAB, 0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_COMMENT, SHT_PROGDEF,0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_NOTE,SHT_NOTE, 0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_GNUSTACK,SHT_PROGDEF,0, 0,0,0,0,0, 1,0);
elf_newsection2(NAMIDX_CDATAREL,SHT_PROGDEF,SHF_ALLOC|SHF_WRITE,0,0,0,0,0, 1,0);
IDXSTR namidx;
namidx = NAMIDX_TEXT; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_RELTEXT; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_DATA; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_RELDATA; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_BSS; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_RODATA; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_STRTAB; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_SYMTAB; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_SHSTRTAB; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_COMMENT; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_NOTE; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_GNUSTACK; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
namidx = NAMIDX_CDATAREL; *(IDXSTR *)section_names_hashtable->get(&namidx) = namidx;
}
if (SYMbuf)
SYMbuf->setsize(0);
if (shndx_data)
shndx_data->setsize(0);
symbol_idx = 0;
local_cnt = 0;
// The symbols that every object file has
elf_addsym(0, 0, 0, STT_NOTYPE, STB_LOCAL, 0);
elf_addsym(0, 0, 0, STT_FILE, STB_LOCAL, SHN_ABS); // STI_FILE
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_TEXT); // STI_TEXT
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_DATA); // STI_DATA
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_BSS); // STI_BSS
elf_addsym(0, 0, 0, STT_NOTYPE, STB_LOCAL, SHN_TEXT); // STI_GCC
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_RODAT); // STI_RODAT
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_NOTE); // STI_NOTE
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_COM); // STI_COM
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, SHN_CDATAREL); // STI_CDATAREL
// Initialize output buffers for CODE, DATA and COMMENTS
// (NOTE not supported, BSS not required)
seg_count = 0;
elf_getsegment2(SHN_TEXT, STI_TEXT, SHN_RELTEXT);
assert(SegData[CODE]->SDseg == CODE);
elf_getsegment2(SHN_DATA, STI_DATA, SHN_RELDATA);
assert(SegData[DATA]->SDseg == DATA);
elf_getsegment2(SHN_RODAT, STI_RODAT, 0);
assert(SegData[CDATA]->SDseg == CDATA);
elf_getsegment2(SHN_BSS, STI_BSS, 0);
assert(SegData[UDATA]->SDseg == UDATA);
elf_getsegment2(SHN_CDATAREL, STI_CDATAREL, 0);
assert(SegData[CDATAREL]->SDseg == CDATAREL);
elf_getsegment2(SHN_COM, STI_COM, 0);
assert(SegData[COMD]->SDseg == COMD);
if (config.fulltypes)
dwarf_initfile(filename);
return obj;
}
/**************************
* Initialize the start of object output for this particular .o file.
*
* Input:
* filename: Name of source file
* csegname: User specified default code segment name
*/
void Obj::initfile(const char *filename, const char *csegname, const char *modname)
{
//dbg_printf("Obj::initfile(filename = %s, modname = %s)\n",filename,modname);
IDXSTR name = Obj::addstr(symtab_strings, filename);
if (I64)
SymbolTable64[STI_FILE].st_name = name;
else
SymbolTable[STI_FILE].st_name = name;
#if 0
// compiler flag for linker
if (I64)
SymbolTable64[STI_GCC].st_name = Obj::addstr(symtab_strings,"gcc2_compiled.");
else
SymbolTable[STI_GCC].st_name = Obj::addstr(symtab_strings,"gcc2_compiled.");
#endif
if (csegname && *csegname && strcmp(csegname,".text"))
{ // Define new section and make it the default for cseg segment
// NOTE: cseg is initialized to CODE
IDXSEC newsecidx;
Elf32_Shdr *newtextsec;
IDXSYM newsymidx;
SegData[cseg]->SDshtidx = newsecidx =
elf_newsection(csegname,0,SHT_PROGDEF,SHF_ALLOC|SHF_EXECINSTR);
newtextsec = &SecHdrTab[newsecidx];
newtextsec->sh_addralign = 4;
SegData[cseg]->SDsymidx =
elf_addsym(0, 0, 0, STT_SECTION, STB_LOCAL, newsecidx);
}
if (config.fulltypes)
dwarf_initmodule(filename, modname);
}
/***************************
* Renumber symbols so they are
* ordered as locals, weak and then global
* Returns:
* sorted symbol table, caller must free with util_free()
*/
void *elf_renumbersyms()
{ void *symtab;
int nextlocal = 0;
int nextglobal = local_cnt;
SYMIDX *sym_map = (SYMIDX *)util_malloc(sizeof(SYMIDX),symbol_idx);
if (I64)
{
Elf64_Sym *oldsymtab = (Elf64_Sym *)SYMbuf->buf;
Elf64_Sym *symtabend = oldsymtab+symbol_idx;
symtab = util_malloc(sizeof(Elf64_Sym),symbol_idx);
Elf64_Sym *sl = (Elf64_Sym *)symtab;
Elf64_Sym *sg = sl + local_cnt;
int old_idx = 0;
for(Elf64_Sym *s = oldsymtab; s != symtabend; s++)
{ // reorder symbol and map new #s to old
int bind = ELF_ST_BIND(s->st_info);
if (bind == STB_LOCAL)
{
*sl++ = *s;
sym_map[old_idx] = nextlocal++;
}
else
{
*sg++ = *s;
sym_map[old_idx] = nextglobal++;
}
old_idx++;
}
}
else
{
Elf32_Sym *oldsymtab = (Elf32_Sym *)SYMbuf->buf;
Elf32_Sym *symtabend = oldsymtab+symbol_idx;
symtab = util_malloc(sizeof(Elf32_Sym),symbol_idx);
Elf32_Sym *sl = (Elf32_Sym *)symtab;
Elf32_Sym *sg = sl + local_cnt;
int old_idx = 0;
for(Elf32_Sym *s = oldsymtab; s != symtabend; s++)
{ // reorder symbol and map new #s to old
int bind = ELF_ST_BIND(s->st_info);
if (bind == STB_LOCAL)
{
*sl++ = *s;
sym_map[old_idx] = nextlocal++;
}
else
{
*sg++ = *s;
sym_map[old_idx] = nextglobal++;
}
old_idx++;
}
}
// Reorder extended section header indices
if (shndx_data && shndx_data->size())
{
// fill with zeros up to symbol_idx
const size_t shndx_idx = shndx_data->size() / sizeof(Elf64_Word);
shndx_data->writezeros((symbol_idx - shndx_idx) * sizeof(Elf64_Word));
Elf64_Word *old_buf = (Elf64_Word *)shndx_data->buf;
Elf64_Word *tmp_buf = (Elf64_Word *)util_malloc(sizeof(Elf64_Word), symbol_idx);
for (SYMIDX old_idx = 0; old_idx < symbol_idx; ++old_idx)
{
const SYMIDX new_idx = sym_map[old_idx];
tmp_buf[new_idx] = old_buf[old_idx];
}
memcpy(old_buf, tmp_buf, sizeof(Elf64_Word) * symbol_idx);
util_free(tmp_buf);
}
// Renumber the relocations
for (int i = 1; i <= seg_count; i++)
{ // Map indicies in the segment table
seg_data *pseg = SegData[i];
pseg->SDsymidx = sym_map[pseg->SDsymidx];
if (SecHdrTab[pseg->SDshtidx].sh_type == SHT_GROUP)
{ // map symbol index of group section header
unsigned oidx = SecHdrTab[pseg->SDshtidx].sh_info;
assert(oidx < symbol_idx);
// we only have one symbol table
assert(SecHdrTab[pseg->SDshtidx].sh_link == SHN_SYMTAB);
SecHdrTab[pseg->SDshtidx].sh_info = sym_map[oidx];
}