{
Copyright (c) 1998-2006 by Peter Vreman
Contains the binary elf writer
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
****************************************************************************
}
unit ogelf;
{$i fpcdefs.inc}
interface
uses
{ common }
cclasses,globtype,
{ target }
systems,
{ assembler }
cpuinfo,cpubase,aasmbase,aasmtai,aasmdata,assemble,
{ output }
ogbase,
owbase;
type
TElfObjSection = class(TObjSection)
public
secshidx : longint; { index for the section in symtab }
shstridx,
shtype,
shflags,
shlink,
shinfo,
shentsize : longint;
constructor create(AList:TFPHashObjectList;const Aname:string;Aalign:shortint;Aoptions:TObjSectionOptions);override;
constructor create_ext(AList:TFPHashObjectList;const Aname:string;Ashtype,Ashflags,Ashlink,Ashinfo:longint;Aalign:shortint;Aentsize:longint);
destructor destroy;override;
end;
TElfObjData = class(TObjData)
public
constructor create(const n:string);override;
destructor destroy;override;
function sectionname(atype:TAsmSectiontype;const aname:string;aorder:TAsmSectionOrder):string;override;
procedure CreateDebugSections;override;
procedure writereloc(data,len:aint;p:TObjSymbol;reltype:TObjRelocationType);override;
end;
TElfObjectOutput = class(tObjOutput)
private
symtabsect,
strtabsect,
shstrtabsect,
gotpcsect,
gotoffsect,
goTSect,
plTSect,
symsect : TElfObjSection;
elf32data : TElfObjData;
symidx,
localsyms : longint;
procedure createrelocsection(s:TElfObjSection);
procedure createshstrtab;
procedure createsymtab;
procedure writesectionheader(s:TElfObjSection);
procedure writesectiondata(s:TElfObjSection);
procedure write_internal_symbol(astridx:longint;ainfo:byte;ashndx:word);
procedure section_write_symbol(p:TObject;arg:pointer);
procedure section_write_sh_string(p:TObject;arg:pointer);
procedure section_count_sections(p:TObject;arg:pointer);
procedure section_create_relocsec(p:TObject;arg:pointer);
procedure section_set_datapos(p:TObject;arg:pointer);
procedure section_write_data(p:TObject;arg:pointer);
procedure section_write_sechdr(p:TObject;arg:pointer);
protected
function writedata(data:TObjData):boolean;override;
public
constructor Create(AWriter:TObjectWriter);override;
destructor Destroy;override;
end;
TElfAssembler = class(tinternalassembler)
constructor create(smart:boolean);override;
end;
implementation
uses
SysUtils,
verbose,
cutils,globals,fmodule;
const
symbolresize = 200*18;
const
{ Relocation types }
{$ifdef i386}
R_386_32 = 1; { ordinary absolute relocation }
R_386_PC32 = 2; { PC-relative relocation }
R_386_GOT32 = 3; { an offset into GOT }
R_386_PLT32 = 4; { a PC-relative offset into PLT }
R_386_GOTOFF = 9; { an offset from GOT base }
R_386_GOTPC = 10; { a PC-relative offset _to_ GOT }
R_386_GNU_VTINHERIT = 250;
R_386_GNU_VTENTRY = 251;
{$endif i386}
{$ifdef sparc}
R_SPARC_32 = 3;
R_SPARC_WDISP30 = 7;
R_SPARC_HI22 = 9;
R_SPARC_LO10 = 12;
R_SPARC_GNU_VTINHERIT = 250;
R_SPARC_GNU_VTENTRY = 251;
{$endif sparc}
{$ifdef x86_64}
R_X86_64_NONE = 0;
{ Direct 64 bit }
R_X86_64_64 = 1;
{ PC relative 32 bit signed }
R_X86_64_PC32 = 2;
{ 32 bit GOT entry }
R_X86_64_GOT32 = 3;
{ 32 bit PLT address }
R_X86_64_PLT32 = 4;
{ Copy symbol at runtime }
R_X86_64_COPY = 5;
{ Create GOT entry }
R_X86_64_GLOB_DAT = 6;
{ Create PLT entry }
R_X86_64_JUMP_SLOT = 7;
{ Adjust by program base }
R_X86_64_RELATIVE = 8;
{ 32 bit signed PC relative offset to GOT }
R_X86_64_GOTPCREL = 9;
{ Direct 32 bit zero extended }
R_X86_64_32 = 10;
{ Direct 32 bit sign extended }
R_X86_64_32S = 11;
{ Direct 16 bit zero extended }
R_X86_64_16 = 12;
{ 16 bit sign extended PC relative }
R_X86_64_PC16 = 13;
{ Direct 8 bit sign extended }
R_X86_64_8 = 14;
{ 8 bit sign extended PC relative }
R_X86_64_PC8 = 15;
{ ID of module containing symbol }
R_X86_64_DTPMOD64 = 16;
{ Offset in module's TLS block }
R_X86_64_DTPOFF64 = 17;
{ Offset in initial TLS block }
R_X86_64_TPOFF64 = 18;
{ 32 bit signed PC relative offset to two GOT entries for GD symbol }
R_X86_64_TLSGD = 19;
{ 32 bit signed PC relative offset to two GOT entries for LD symbol }
R_X86_64_TLSLD = 20;
{ Offset in TLS block }
R_X86_64_DTPOFF32 = 21;
{ 32 bit signed PC relative offset to GOT entry for IE symbol }
R_X86_64_GOTTPOFF = 22;
{ Offset in initial TLS block }
R_X86_64_TPOFF32 = 23;
{ GNU extension to record C++ vtable hierarchy }
R_X86_64_GNU_VTINHERIT = 24;
{ GNU extension to record C++ vtable member usage }
R_X86_64_GNU_VTENTRY = 25;
{$endif x86_64}
SHN_UNDEF = 0;
SHN_ABS = $fff1;
SHN_COMMON = $fff2;
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_WRITE = 1;
SHF_ALLOC = 2;
SHF_EXECINSTR = 4;
STB_LOCAL = 0;
STB_GLOBAL = 1;
STB_WEAK = 2;
STT_NOTYPE = 0;
STT_OBJECT = 1;
STT_FUNC = 2;
STT_SECTION = 3;
STT_FILE = 4;
type
{ Structures which are written directly to the output file }
TElf32header=packed record
magic0123 : longint;
file_class : byte;
data_encoding : byte;
file_version : byte;
padding : array[$07..$0f] of byte;
e_type : word;
e_machine : word;
e_version : longint;
e_entry : longint; { entrypoint }
e_phoff : longint; { program header offset }
e_shoff : longint; { sections header offset }
e_flags : longint;
e_ehsize : word; { elf header size in bytes }
e_phentsize : word; { size of an entry in the program header array }
e_phnum : word; { 0..e_phnum-1 of entrys }
e_shentsize : word; { size of an entry in sections header array }
e_shnum : word; { 0..e_shnum-1 of entrys }
e_shstrndx : word; { index of string section header }
end;
TElf32sechdr=packed record
sh_name : longint;
sh_type : longint;
sh_flags : longint;
sh_addr : longint;
sh_offset : longint;
sh_size : longint;
sh_link : longint;
sh_info : longint;
sh_addralign : longint;
sh_entsize : longint;
end;
TElf32reloc=packed record
address : longint;
info : longint; { bit 0-7: type, 8-31: symbol }
end;
TElf32symbol=packed record
st_name : longint;
st_value : longint;
st_size : longint;
st_info : byte; { bit 0-3: type, 4-7: bind }
st_other : byte;
st_shndx : word;
end;
telf64header=packed record
magic0123 : longint;
file_class : byte;
data_encoding : byte;
file_version : byte;
padding : array[$07..$0f] of byte;
e_type : word;
e_machine : word;
e_version : longint;
e_entry : qword; { entrypoint }
e_phoff : qword; { program header offset }
e_shoff : qword; { sections header offset }
e_flags : longint;
e_ehsize : word; { elf header size in bytes }
e_phentsize : word; { size of an entry in the program header array }
e_phnum : word; { 0..e_phnum-1 of entrys }
e_shentsize : word; { size of an entry in sections header array }
e_shnum : word; { 0..e_shnum-1 of entrys }
e_shstrndx : word; { index of string section header }
end;
telf64sechdr=packed record
sh_name : longint;
sh_type : longint;
sh_flags : qword;
sh_addr : qword;
sh_offset : qword;
sh_size : qword;
sh_link : longint;
sh_info : longint;
sh_addralign : qword;
sh_entsize : qword;
end;
telf64reloc=packed record
address : qword;
info : qword; { bit 0-7: type, 8-31: symbol }
addend : qword;
end;
telf64symbol=packed record
st_name : longint;
st_info : byte; { bit 0-3: type, 4-7: bind }
st_other : byte;
st_shndx : word;
st_value : qword;
st_size : qword;
end;
{$ifdef cpu64bit}
telfheader = telf64header;
telfreloc = telf64reloc;
telfsymbol = telf64symbol;
telfsechdr = telf64sechdr;
{$else cpu64bit}
telfheader = telf32header;
telfreloc = telf32reloc;
telfsymbol = telf32symbol;
telfsechdr = telf32sechdr;
{$endif cpu64bit}
function MayBeSwapHeader(h : telf32header) : telf32header;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.e_type:=swapword(e_type);
result.e_machine:=swapword(e_machine);
result.e_version:=swaplong(e_version);
result.e_entry:=swaplong(e_entry);
result.e_phoff:=swaplong(e_phoff);
result.e_shoff:=swaplong(e_shoff);
result.e_flags:=swaplong(e_flags);
result.e_ehsize:=swapword(e_ehsize);
result.e_phentsize:=swapword(e_phentsize);
result.e_phnum:=swapword(e_phnum);
result.e_shentsize:=swapword(e_shentsize);
result.e_shnum:=swapword(e_shnum);
result.e_shstrndx:=swapword(e_shstrndx);
end;
end;
function MayBeSwapHeader(h : telf64header) : telf64header;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.e_type:=swapword(e_type);
result.e_machine:=swapword(e_machine);
result.e_version:=swaplong(e_version);
result.e_entry:=swapqword(e_entry);
result.e_phoff:=swapqword(e_phoff);
result.e_shoff:=swapqword(e_shoff);
result.e_flags:=swaplong(e_flags);
result.e_ehsize:=swapword(e_ehsize);
result.e_phentsize:=swapword(e_phentsize);
result.e_phnum:=swapword(e_phnum);
result.e_shentsize:=swapword(e_shentsize);
result.e_shnum:=swapword(e_shnum);
result.e_shstrndx:=swapword(e_shstrndx);
end;
end;
function MaybeSwapSecHeader(h : telf32sechdr) : telf32sechdr;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.sh_name:=SwapLong(sh_name);
result.sh_type:=SwapLong(sh_type);
result.sh_flags:=SwapLong(sh_flags);
result.sh_addr:=SwapLong(sh_addr);
result.sh_offset:=SwapLong(sh_offset);
result.sh_size:=SwapLong(sh_size);
result.sh_link:=SwapLong(sh_link);
result.sh_info:=SwapLong(sh_info);
result.sh_addralign:=SwapLong(sh_addralign);
result.sh_entsize:=SwapLong(sh_entsize);
end;
end;
function MaybeSwapSecHeader(h : telf64sechdr) : telf64sechdr;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.sh_name:=SwapLong(sh_name);
result.sh_type:=SwapLong(sh_type);
result.sh_flags:=SwapQWord(sh_flags);
result.sh_addr:=SwapQWord(sh_addr);
result.sh_offset:=SwapQWord(sh_offset);
result.sh_size:=SwapQWord(sh_size);
result.sh_link:=SwapLong(sh_link);
result.sh_info:=SwapLong(sh_info);
result.sh_addralign:=SwapQWord(sh_addralign);
result.sh_entsize:=SwapQWord(sh_entsize);
end;
end;
function MaybeSwapElfSymbol(h : telf32symbol) : telf32symbol;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.st_name:=SwapLong(st_name);
result.st_value:=SwapLong(st_value);
result.st_size:=SwapLong(st_size);
result.st_shndx:=SwapWord(st_shndx);
end;
end;
function MaybeSwapElfSymbol(h : telf64symbol) : telf64symbol;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.st_name:=SwapLong(st_name);
result.st_value:=SwapQWord(st_value);
result.st_size:=SwapQWord(st_size);
result.st_shndx:=SwapWord(st_shndx);
end;
end;
function MaybeSwapElfReloc(h : telf32reloc) : telf32reloc;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.address:=SwapLong(address);
result.info:=SwapLong(info);
end;
end;
function MaybeSwapElfReloc(h : telf64reloc) : telf64reloc;
begin
result:=h;
if source_info.endian<>target_info.endian then
with h do
begin
result.address:=SwapQWord(address);
result.info:=SwapQWord(info);
end;
end;
{****************************************************************************
Helpers
****************************************************************************}
procedure encodesechdrflags(aoptions:TObjSectionOptions;out AshType:longint;out Ashflags:longint);
begin
{ Section Type }
AshType:=SHT_PROGBITS;
if oso_strings in aoptions then
AshType:=SHT_STRTAB
else if not(oso_data in aoptions) then
AshType:=SHT_NOBITS;
{ Section Flags }
Ashflags:=0;
if oso_load in aoptions then
Ashflags:=Ashflags or SHF_ALLOC;
if oso_executable in aoptions then
Ashflags:=Ashflags or SHF_EXECINSTR;
if oso_write in aoptions then
Ashflags:=Ashflags or SHF_WRITE;
end;
procedure decodesechdrflags(AshType:longint;Ashflags:longint;out aoptions:TObjSectionOptions);
begin
aoptions:=[];
{ Section Type }
if AshType<>SHT_NOBITS then
include(aoptions,oso_data);
if AshType=SHT_STRTAB then
include(aoptions,oso_strings);
{ Section Flags }
if Ashflags and SHF_ALLOC<>0 then
include(aoptions,oso_load)
else
include(aoptions,oso_noload);
if Ashflags and SHF_WRITE<>0 then
include(aoptions,oso_write)
else
include(aoptions,oso_readonly);
end;
{****************************************************************************
TSection
****************************************************************************}
constructor TElfObjSection.create(AList:TFPHashObjectList;const Aname:string;Aalign:shortint;Aoptions:TObjSectionOptions);
begin
inherited create(AList,Aname,Aalign,aoptions);
secshidx:=0;
shstridx:=0;
encodesechdrflags(aoptions,shtype,shflags);
shlink:=0;
shinfo:=0;
if name='.stab' then
shentsize:=sizeof(TObjStabEntry);
end;
constructor TElfObjSection.create_ext(AList:TFPHashObjectList;const Aname:string;Ashtype,Ashflags,Ashlink,Ashinfo:longint;Aalign:shortint;Aentsize:longint);
var
aoptions : TObjSectionOptions;
begin
decodesechdrflags(Ashtype,Ashflags,aoptions);
inherited create(AList,Aname,Aalign,aoptions);
secshidx:=0;
shstridx:=0;
shtype:=AshType;
shflags:=AshFlags;
shlink:=Ashlink;
shinfo:=Ashinfo;
shentsize:=Aentsize;
end;
destructor TElfObjSection.destroy;
begin
inherited destroy;
end;
{****************************************************************************
TElfObjData
****************************************************************************}
constructor TElfObjData.create(const n:string);
begin
inherited create(n);
CObjSection:=TElfObjSection;
{ we need at least the following sections }
createsection(sec_code);
createsection(sec_data);
createsection(sec_bss);
if tf_section_threadvars in target_info.flags then
createsection(sec_threadvar);
if (tf_needs_dwarf_cfi in target_info.flags) and
(af_supports_dwarf in target_asm.flags) then
createsection(sec_debug_frame);
end;
destructor TElfObjData.destroy;
begin
inherited destroy;
end;
function TElfObjData.sectionname(atype:TAsmSectiontype;const aname:string;aorder:TAsmSectionOrder):string;
const
secnames : array[TAsmSectiontype] of string[13] = ('',
{$ifdef userodata}
'.text','.data','.rodata','.bss','.threadvar',
{$else userodata}
'.text','.data','.data','.bss','.threadvar',
{$endif userodata}
'.pdata',
'.text', { darwin stubs }
'.stab','.stabstr',
'.idata$2','.idata$4','.idata$5','.idata$6','.idata$7','.edata',
'.eh_frame',
'.debug_frame','.debug_info','.debug_line','.debug_abbrev',
'.fpc',
'.toc',
'.init'
);
secnames_pic : array[TAsmSectiontype] of string[17] = ('',
'.text',
'.data.rel',
'.data.rel',
'.bss',
'.threadvar',
'.pdata',
'', { stubs }
'.stab',
'.stabstr',
'.idata$2','.idata$4','.idata$5','.idata$6','.idata$7','.edata',
'.eh_frame',
'.debug_frame','.debug_info','.debug_line','.debug_abbrev',
'.fpc',
'.toc',
'.init'
);
var
sep : string[3];
secname : string;
begin
if (cs_create_pic in current_settings.moduleswitches) and
not(target_info.system in [system_powerpc_darwin,system_i386_darwin]) then
secname:=secnames_pic[atype]
else
secname:=secnames[atype];
if (atype=sec_fpc) and (Copy(aname,1,3)='res') then
begin
result:=secname+'.'+aname;
exit;
end;
if use_smartlink_section and (aname<>'') then
begin
case aorder of
secorder_begin :
sep:='.b_';
secorder_end :
sep:='.z_';
else
sep:='.n_';
end;
result:=secname+sep+aname
end
else
result:=secname;
end;
procedure TElfObjData.CreateDebugSections;
begin
if target_dbg.id=dbg_stabs then
begin
stabssec:=createsection(sec_stab);
stabstrsec:=createsection(sec_stabstr);
end;
end;
procedure TElfObjData.writereloc(data,len:aint;p:TObjSymbol;reltype:TObjRelocationType);
var
symaddr : longint;
begin
if CurrObjSec=nil then
internalerror(200403292);
{$ifdef userodata}
if CurrObjSec.sectype in [sec_rodata,sec_bss,sec_threadvar] then
internalerror(200408252);
{$endif userodata}
if assigned(p) then
begin
{ real address of the symbol }
symaddr:=p.address;
{ Local ObjSymbols can be resolved already or need a section reloc }
if (p.bind=AB_LOCAL) and
(reltype in [RELOC_RELATIVE,RELOC_ABSOLUTE{$ifdef x86_64},RELOC_ABSOLUTE32{$endif x86_64}]) then
begin
{ For a reltype relocation in the same section the
value can be calculated }
if (p.objsection=CurrObjSec) and
(reltype=RELOC_RELATIVE) then
inc(data,symaddr-len-CurrObjSec.Size)
else
begin
CurrObjSec.addsectionreloc(CurrObjSec.Size,p.objsection,reltype);
inc(data,symaddr);
end;
end
else
begin
CurrObjSec.addsymreloc(CurrObjSec.Size,p,reltype);
{$ifndef x86_64}
if reltype=RELOC_RELATIVE then
dec(data,len);
{$endif x86_64}
end;
end;
CurrObjSec.write(data,len);
end;
{****************************************************************************
TElfObjectOutput
****************************************************************************}
constructor TElfObjectOutput.create(AWriter:TObjectWriter);
begin
inherited Create(AWriter);
CObjData:=TElfObjData;
end;
destructor TElfObjectOutput.destroy;
begin
inherited destroy;
end;
procedure TElfObjectOutput.createrelocsection(s:TElfObjSection);
var
i : longint;
rel : telfreloc;
objreloc : TObjRelocation;
relsym,
reltyp : longint;
relocsect : TObjSection;
begin
with elf32data do
begin
{$ifdef userodata}
{ rodata can't have relocations }
if s.sectype=sec_rodata then
begin
if assigned(s.relocations.first) then
internalerror(200408251);
exit;
end;
{$endif userodata}
{ create the reloc section }
{$ifdef i386}
relocsect:=TElfObjSection.create_ext(ObjSectionList,'.rel'+s.name,SHT_REL,0,symtabsect.secshidx,s.secshidx,4,sizeof(TElfReloc));
{$else i386}
relocsect:=TElfObjSection.create_ext(ObjSectionList,'.rela'+s.name,SHT_RELA,0,symtabsect.secshidx,s.secshidx,4,sizeof(TElfReloc));
{$endif i386}
{ add the relocations }
for i:=0 to s.Objrelocations.count-1 do
begin
objreloc:=TObjRelocation(s.Objrelocations[i]);
fillchar(rel,sizeof(rel),0);
rel.address:=objreloc.dataoffset;
{ when things settle down, we can create processor specific
derived classes }
case objreloc.typ of
{$ifdef i386}
RELOC_RELATIVE :
reltyp:=R_386_PC32;
RELOC_ABSOLUTE :
reltyp:=R_386_32;
{$endif i386}
{$ifdef sparc}
RELOC_ABSOLUTE :
reltyp:=R_SPARC_32;
{$endif sparc}
{$ifdef x86_64}
RELOC_RELATIVE :
begin
reltyp:=R_X86_64_PC32;
{ length of the relocated location is handled here }
rel.addend:=qword(-4);
end;
RELOC_ABSOLUTE :
reltyp:=R_X86_64_64;
RELOC_ABSOLUTE32 :
reltyp:=R_X86_64_32S;
RELOC_GOTPCREL :
begin
reltyp:=R_X86_64_GOTPCREL;
{ length of the relocated location is handled here }
rel.addend:=qword(-4);
end;
RELOC_PLT32 :
begin
reltyp:=R_X86_64_PLT32;
{ length of the relocated location is handled here }
rel.addend:=qword(-4);
end;
{$endif x86_64}
else
internalerror(200602261);
end;
{ Symbol }
if assigned(objreloc.symbol) then
begin
if objreloc.symbol.symidx=-1 then
begin
writeln(objreloc.symbol.Name);
internalerror(200603012);
end;
relsym:=objreloc.symbol.symidx;
end
else
begin
if objreloc.objsection<>nil then
relsym:=objreloc.objsection.secsymidx
else
relsym:=SHN_UNDEF;
end;
{$ifdef cpu64bit}
rel.info:=(qword(relsym) shl 32) or reltyp;
{$else cpu64bit}
rel.info:=(relsym shl 8) or reltyp;
{$endif cpu64bit}
{ write reloc }
relocsect.write(MaybeSwapElfReloc(rel),sizeof(rel));
end;
end;
end;
procedure TElfObjectOutput.write_internal_symbol(astridx:longint;ainfo:byte;ashndx:word);
var
elfsym : telfsymbol;
begin
fillchar(elfsym,sizeof(elfsym),0);
elfsym.st_name:=astridx;
elfsym.st_info:=ainfo;
elfsym.st_shndx:=ashndx;
inc(symidx);
inc(localsyms);
symtabsect.write(MaybeSwapElfSymbol(elfsym),sizeof(elfsym));
end;
procedure TElfObjectOutput.section_write_symbol(p:TObject;arg:pointer);
begin
TObjSection(p).secsymidx:=symidx;
write_internal_symbol(TElfObjSection(p).shstridx,STT_SECTION,TElfObjSection(p).secshidx);
end;
procedure TElfObjectOutput.createsymtab;
procedure WriteSym(objsym:TObjSymbol);
var
elfsym : telfsymbol;
begin
with elf32data do
begin
fillchar(elfsym,sizeof(elfsym),0);
{ symbolname, write the #0 separate to overcome 255+1 char not possible }
elfsym.st_name:=strtabsect.Size;
strtabsect.writestr(objsym.name);
strtabsect.writestr(#0);
elfsym.st_size:=objsym.size;
case objsym.bind of
AB_LOCAL :
begin
elfsym.st_value:=objsym.address;
elfsym.st_info:=STB_LOCAL shl 4;
inc(localsyms);
end;
AB_COMMON :
begin
elfsym.st_value:=$10;
elfsym.st_info:=STB_GLOBAL shl 4;
end;
AB_EXTERNAL :
elfsym.st_info:=STB_GLOBAL shl 4;
AB_GLOBAL :
begin
elfsym.st_value:=objsym.address;
elfsym.st_info:=STB_GLOBAL shl 4;
end;
end;
if (objsym.bind<>AB_EXTERNAL) {and
not(assigned(objsym.objsection) and
not(oso_data in objsym.objsection.secoptions))} then
begin
case objsym.typ of
AT_FUNCTION :
elfsym.st_info:=elfsym.st_info or STT_FUNC;
AT_DATA :
elfsym.st_info:=elfsym.st_info or STT_OBJECT;
end;
end;
if objsym.bind=AB_COMMON then
elfsym.st_shndx:=SHN_COMMON
else
begin
if assigned(objsym.objsection) then
elfsym.st_shndx:=TElfObjSection(objsym.objsection).secshidx
else
elfsym.st_shndx:=SHN_UNDEF;
end;
objsym.symidx:=symidx;
inc(symidx);
symtabsect.write(MaybeSwapElfSymbol(elfsym),sizeof(elfsym));
end;
end;
var
i : longint;
objsym : TObjSymbol;
begin
with elf32data do
begin
symidx:=0;
localsyms:=0;
{ empty entry }
write_internal_symbol(0,0,0);
{ filename entry }
write_internal_symbol(1,STT_FILE,SHN_ABS);
{ section }
ObjSectionList.ForEachCall(@section_write_symbol,nil);
{ First the Local Symbols, this is required by ELF. The localsyms
count stored in shinfo is used to skip the local symbols
when traversing the symtab }
for i:=0 to ObjSymbolList.Count-1 do
begin
objsym:=TObjSymbol(ObjSymbolList[i]);
if (objsym.bind=AB_LOCAL) and (objsym.typ<>AT_LABEL) then
WriteSym(objsym);
end;
{ Global Symbols }
for i:=0 to ObjSymbolList.Count-1 do
begin
objsym:=TObjSymbol(ObjSymbolList[i]);
if (objsym.bind<>AB_LOCAL) then
WriteSym(objsym);
end;
{ update the .symtab section header }
symtabsect.shlink:=strtabsect.secshidx;
symtabsect.shinfo:=localsyms;
end;
end;
procedure TElfObjectOutput.section_write_sh_string(p:TObject;arg:pointer);
begin
TElfObjSection(p).shstridx:=shstrtabsect.writestr(TObjSection(p).name+#0);
end;
procedure TElfObjectOutput.createshstrtab;
begin
with elf32data do
begin
shstrtabsect.writestr(#0);
ObjSectionList.ForEachCall(@section_write_sh_string,nil);
end;
end;
procedure TElfObjectOutput.writesectionheader(s:TElfObjSection);
var
sechdr : telfsechdr;
begin
fillchar(sechdr,sizeof(sechdr),0);
sechdr.sh_name:=s.shstridx;
sechdr.sh_type:=s.shtype;
sechdr.sh_flags:=s.shflags;
sechdr.sh_offset:=s.datapos;
sechdr.sh_size:=s.Size;
sechdr.sh_link:=s.shlink;
sechdr.sh_info:=s.shinfo;
sechdr.sh_addralign:=s.secalign;
sechdr.sh_entsize:=s.shentsize;
writer.write(MaybeSwapSecHeader(sechdr),sizeof(sechdr));
end;
procedure TElfObjectOutput.writesectiondata(s:TElfObjSection);
begin
FWriter.writezeros(s.dataalignbytes);
if s.Datapos<>FWriter.ObjSize then
internalerror(200604031);
FWriter.writearray(s.data);
end;
procedure TElfObjectOutput.section_count_sections(p:TObject;arg:pointer);
begin
TElfObjSection(p).secshidx:=pword(arg)^;
inc(pword(arg)^);
end;
procedure TElfObjectOutput.section_create_relocsec(p:TObject;arg:pointer);
begin
if (TElfObjSection(p).ObjRelocations.count>0) then
createrelocsection(TElfObjSection(p));
end;
procedure TElfObjectOutput.section_set_datapos(p:TObject;arg:pointer);
begin
TObjSection(p).setdatapos(paint(arg)^);
end;
procedure TElfObjectOutput.section_write_data(p:TObject;arg:pointer);
begin
if (oso_data in TObjSection(p).secoptions) then
begin
if TObjSection(p).data=nil then
internalerror(200403073);
writesectiondata(TElfObjSection(p));
end;
end;
procedure TElfObjectOutput.section_write_sechdr(p:TObject;arg:pointer);
begin
writesectionheader(TElfObjSection(p));
end;
function TElfObjectOutput.writedata(data:TObjData):boolean;
var
header : telfheader;
shoffset,
datapos : aint;
nsections : word;
begin
result:=false;
elf32data:=TElfObjData(data);
with elf32data do
begin
{ default sections }
symtabsect:=TElfObjSection.create_ext(ObjSectionList,'.symtab',SHT_SYMTAB,0,0,0,4,sizeof(telfsymbol));
strtabsect:=TElfObjSection.create_ext(ObjSectionList,'.strtab',SHT_STRTAB,0,0,0,1,0);
shstrtabsect:=TElfObjSection.create_ext(ObjSectionList,'.shstrtab',SHT_STRTAB,0,0,0,1,0);
{ insert the empty and filename as first in strtab }
strtabsect.writestr(#0);
strtabsect.writestr(ExtractFileName(current_module.mainsource^)+#0);
{ calc amount of sections we have }
nsections:=1;
{ also create the index in the section header table }
ObjSectionList.ForEachCall(@section_count_sections,@nsections);
{ create .symtab and .strtab }
createsymtab;
{ Create the relocation sections, this needs valid secidx and symidx }
ObjSectionList.ForEachCall(@section_create_relocsec,nil);
{ recalc nsections to incude the reloc sections }
nsections:=1;
ObjSectionList.ForEachCall(@section_count_sections,@nsections);
{ create .shstrtab }
createshstrtab;
{ Calculate the filepositions }
datapos:=$40; { elfheader + alignment }
{ section data }
ObjSectionList.ForEachCall(@section_set_datapos,@datapos);
{ section headers }
shoffset:=datapos;
inc(datapos,(nsections+1)*sizeof(telfsechdr));
{ Write ELF Header }
fillchar(header,sizeof(header),0);
header.magic0123:=$464c457f; { = #127'ELF' }
{$ifdef cpu64bit}
header.file_class:=2;
{$else cpu64bit}
header.file_class:=1;
{$endif cpu64bit}
if target_info.endian=endian_big then
header.data_encoding:=2
else
header.data_encoding:=1;
header.file_version:=1;
header.e_type:=1;
{$ifdef sparc}
header.e_machine:=2;
{$endif sparc}
{$ifdef i386}
header.e_machine:=3;
{$endif i386}
{$ifdef m68k}
header.e_machine:=4;
{$endif m68k}
{$ifdef powerpc}
header.e_machine:=20;
{$endif powerpc}
{$ifdef arm}
header.e_machine:=40;
{$endif arm}
{$ifdef x86_64}
header.e_machine:=62;
{$endif x86_64}
header.e_version:=1;
header.e_shoff:=shoffset;
header.e_shstrndx:=shstrtabsect.secshidx;
header.e_shnum:=nsections;
header.e_ehsize:=sizeof(telfheader);
header.e_shentsize:=sizeof(telfsechdr);
writer.write(MaybeSwapHeader(header),sizeof(header));
writer.writezeros($40-sizeof(header)); { align }
{ Sections }
ObjSectionList.ForEachCall(@section_write_data,nil);
{ section headers, start with an empty header for sh_undef }
writer.writezeros(sizeof(telfsechdr));
ObjSectionList.ForEachCall(@section_write_sechdr,nil);
end;
result:=true;
end;
{****************************************************************************
TELFAssembler
****************************************************************************}
constructor TElfAssembler.Create(smart:boolean);
begin
inherited Create(smart);
CObjOutput:=TElfObjectOutput;
end;
{*****************************************************************************
Initialize
*****************************************************************************}
{$ifdef i386}
const
as_i386_elf32_info : tasminfo =
(
id : as_i386_elf32;
idtxt : 'ELF';
asmbin : '';
asmcmd : '';
supported_target : system_any; //target_i386_linux;
flags : [af_outputbinary,af_smartlink_sections,af_supports_dwarf];
labelprefix : '.L';
comment : '';
);
{$endif i386}
{$ifdef x86_64}
const
as_x86_64_elf64_info : tasminfo =
(
id : as_x86_64_elf64;
idtxt : 'ELF';
asmbin : '';
asmcmd : '';
supported_target : system_any; //target_i386_linux;
flags : [af_outputbinary,af_smartlink_sections,af_supports_dwarf];
labelprefix : '.L';
comment : '';
);
{$endif x86_64}
{$ifdef sparc}
const
as_sparc_elf32_info : tasminfo =
(
id : as_sparc_elf32;
idtxt : 'ELF';
asmbin : '';
asmcmd : '';
supported_target : system_any; //target_i386_linux;
// flags : [af_outputbinary,af_smartlink_sections];
flags : [af_outputbinary,af_supports_dwarf];
labelprefix : '.L';
comment : '';
);
{$endif sparc}
initialization
{$ifdef i386}
RegisterAssembler(as_i386_elf32_info,TElfAssembler);
{$endif i386}
{$ifdef sparc}
RegisterAssembler(as_sparc_elf32_info,TElfAssembler);
{$endif sparc}
{$ifdef x86_64}
RegisterAssembler(as_x86_64_elf64_info,TElfAssembler);
{$endif x86_64}
end.
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