{ $Id$ Copyright (c) 1998-2002 by Peter Vreman Contains the binary elf writer * This code was inspired by the NASM sources The Netwide Assembler is Copyright (c) 1996 Simon Tatham and Julian Hall. All rights reserved. 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; {$i fpcdefs.inc} interface uses { common } cclasses, { target } systems, { assembler } cpubase,aasmbase,assemble, { output } ogbase; type telf32section = class(TAsmSection) public secshidx : longint; { index for the section in symtab } shstridx, shtype, shflags, shlink, shinfo, entsize : longint; { relocation } relocsect : telf32Section; constructor createsec(sec:TSection); constructor createname(const Aname:string;Atype,Aflags,Alink,Ainfo,Aalign,Aentsize:longint); destructor destroy;override; end; telf32objectdata = class(TAsmObjectData) public symtabsect, strtabsect, shstrtabsect, gotpcsect, gotoffsect, goTSect, plTSect, symsect : telf32Section; syms : Tdynamicarray; constructor create(const n:string); destructor destroy;override; procedure createsection(sec:TSection);override; procedure seTSectionsizes(var s:TAsmSectionSizes);override; procedure writereloc(data,len:longint;p:tasmsymbol;relative:TAsmRelocationType);override; procedure writesymbol(p:tasmsymbol);override; procedure writestabs(section:TSection;offset:longint;p:pchar;nidx,nother,line:longint;reloc:boolean);override; procedure writesymstabs(section:TSection;offset:longint;p:pchar;ps:tasmsymbol; nidx,nother,line:longint;reloc:boolean);override; end; telf32objectoutput = class(tobjectoutput) private elf32data : telf32objectdata; initsym : longint; procedure createrelocsection(s:telf32section); procedure createshstrtab; procedure createsymtab; procedure writesectionheader(s:telf32section); protected function writedata(data:TAsmObjectData):boolean;override; public function newobjectdata(const n:string):TAsmObjectData;override; end; telf32assembler = class(tinternalassembler) constructor create(smart:boolean);override; end; implementation uses {$ifdef delphi} sysutils, {$else} strings, {$endif} verbose, globtype,cutils,globals,fmodule; const symbolresize = 200*18; const 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 } 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; telf32stab=packed record strpos : longint; ntype : byte; nother : byte; ndesc : word; nvalue : longint; end; {**************************************************************************** TSection ****************************************************************************} constructor telf32section.createsec(sec:TSection); var Aflags,Atype,Aalign,Aentsize : longint; begin Aflags:=0; Atype:=0; Aalign:=0; Aentsize:=0; case sec of sec_code : begin Aflags:=SHF_ALLOC or SHF_EXECINSTR; AType:=SHT_PROGBITS; AAlign:=16; end; sec_data : begin Aflags:=SHF_ALLOC or SHF_WRITE; AType:=SHT_PROGBITS; AAlign:=4; end; sec_bss : begin Aflags:=SHF_ALLOC or SHF_WRITE; AType:=SHT_NOBITS; AAlign:=4; end; sec_stab : begin AType:=SHT_PROGBITS; AAlign:=4; Aentsize:=sizeof(telf32stab); end; sec_stabstr : begin AType:=SHT_STRTAB; AAlign:=1; end; end; createname(target_asm.secnames[sec],Atype,Aflags,0,0,Aalign,Aentsize); end; constructor telf32section.createname(const Aname:string;Atype,Aflags,Alink,Ainfo,Aalign,Aentsize:longint); begin inherited create(Aname,Aalign,(AType=SHT_NOBITS)); secshidx:=0; shstridx:=0; shtype:=AType; shflags:=AFlags; shlink:=Alink; shinfo:=Ainfo; entsize:=Aentsize; relocsect:=nil; end; destructor telf32section.destroy; begin if assigned(relocsect) then relocsect.free; inherited destroy; end; {**************************************************************************** telf32objectdata ****************************************************************************} constructor telf32objectdata.create(const n:string); var s : string; begin inherited create(n); { reset } Syms:=TDynamicArray.Create(symbolresize); { default sections } symtabsect:=telf32section.createname('.symtab',2,0,0,0,4,16); strtabsect:=telf32section.createname('.strtab',3,0,0,0,1,0); shstrtabsect:=telf32section.createname('.shstrtab',3,0,0,0,1,0); { insert the empty and filename as first in strtab } strtabsect.writestr(#0); strtabsect.writestr(SplitFileName(current_module.mainsource^)+#0); { we need at least the following sections } createsection(sec_code); createsection(sec_data); createsection(sec_bss); { create stabs sections if debugging } if (cs_debuginfo in aktmoduleswitches) then begin createsection(sec_stab); createsection(sec_stabstr); writestabs(sec_none,0,nil,0,0,0,false); { write zero pchar and name together (PM) } s:=#0+SplitFileName(current_module.mainsource^)+#0; sects[sec_stabstr].write(s[1],length(s)); end; end; destructor telf32objectdata.destroy; begin Syms.Free; symtabsect.free; strtabsect.free; shstrtabsect.free; inherited destroy; end; procedure telf32objectdata.createsection(sec:TSection); begin sects[sec]:=telf32Section.createsec(Sec); end; procedure telf32objectdata.writesymbol(p:tasmsymbol); begin { already written ? } if p.indexnr<>-1 then exit; { be sure that the section will exists } if (p.section<>sec_none) and not(assigned(sects[p.section])) then createsection(p.section); { calculate symbol index } if (p.currbind<>AB_LOCAL) then begin { insert the symbol in the local index, the indexarray will take care of the numbering } symbols.insert(p); end else p.indexnr:=-2; { local } end; procedure telf32objectdata.writereloc(data,len:longint;p:tasmsymbol;relative:TAsmRelocationType); var symaddr : longint; begin if not assigned(sects[currsec]) then createsection(currsec); if assigned(p) then begin { real address of the symbol } symaddr:=p.address; { no symbol relocation need inside a section } if p.section=currsec then begin case relative of RELOC_ABSOLUTE : begin sects[currsec].addsectionreloc(sects[currsec].datasize,currsec,RELOC_ABSOLUTE); inc(data,symaddr); end; RELOC_RELATIVE : begin inc(data,symaddr-len-sects[currsec].datasize); end; RELOC_RVA : internalerror(3219583); end; end else begin writesymbol(p); if (p.section<>sec_none) and (relative<>RELOC_RELATIVE) then begin sects[currsec].addsectionreloc(sects[currsec].datasize,p.section,relative); inc(data,symaddr); end else sects[currsec].addsymreloc(sects[currsec].datasize,p,relative); if relative=RELOC_RELATIVE then begin if p.currbind=AB_EXTERNAL then dec(data,len) else dec(data,len+sects[currsec].datasize); end; end; end; sects[currsec].write(data,len); end; procedure telf32objectdata.writestabs(section:TSection;offset:longint;p:pchar;nidx,nother,line:longint;reloc : boolean); var stab : telf32stab; begin if reloc then begin if (offset=-1) then begin if section=sec_none then offset:=0 else offset:=sects[section].datasize; end; end; fillchar(stab,sizeof(telf32stab),0); if assigned(p) and (p[0]<>#0) then begin stab.strpos:=sects[sec_stabstr].datasize; sects[sec_stabstr].write(p^,strlen(p)+1); end; stab.ntype:=nidx; stab.ndesc:=line; stab.nother:=nother; stab.nvalue:=offset; sects[sec_stab].write(stab,sizeof(stab)); { when the offset is not 0 then write a relocation, take also the hdrstab into account with the offset } if reloc then sects[sec_stab].addsectionreloc(sects[sec_stab].datasize-4,section,RELOC_ABSOLUTE); end; procedure telf32objectdata.writesymstabs(section:TSection;offset:longint;p:pchar;ps:tasmsymbol; nidx,nother,line:longint;reloc:boolean); var stab : telf32stab; begin fillchar(stab,sizeof(telf32stab),0); if assigned(p) and (p[0]<>#0) then begin stab.strpos:=sects[sec_stabstr].datasize; sects[sec_stabstr].write(p^,strlen(p)+1); end; stab.ntype:=nidx; stab.ndesc:=line; stab.nother:=nother; stab.nvalue:=0; sects[sec_stab].write(stab,sizeof(stab)); { when the offset is not 0 then write a relocation, take also the hdrstab into account with the offset } if reloc then sects[sec_stab].addsymreloc(sects[sec_stab].datasize-4,ps,RELOC_ABSOLUTE); end; procedure telf32objectdata.seTSectionsizes(var s:TAsmSectionSizes); begin end; {**************************************************************************** telf32objectoutput ****************************************************************************} function telf32objectoutput.newobjectdata(const n:string):TAsmObjectData; begin result:=telf32objectdata.create(n); end; procedure telf32objectoutput.createrelocsection(s:telf32section); var rel : telf32reloc; r : tasmrelocation; relsym,reltyp : longint; begin with elf32data do begin { create the reloc section } s.relocsect:=telf32section.createname('.rel'+s.name,9,0,symtabsect.secshidx,s.secshidx,4,8); { add the relocations } r:=TasmRelocation(s.relocations.first); while assigned(r) do begin rel.address:=r.address; if assigned(r.symbol) then begin if (r.symbol.currbind=AB_LOCAL) then relsym:=sects[r.symbol.section].secsymidx else begin if r.symbol.indexnr=-1 then internalerror(4321); { indexnr starts with 1, ELF starts with 0 } relsym:=r.symbol.indexnr+initsym-1; end; end else if r.section<>sec_none then relsym:=sects[r.section].secsymidx else relsym:=SHN_UNDEF; case r.typ of RELOC_RELATIVE : reltyp:=R_386_PC32; RELOC_ABSOLUTE : reltyp:=R_386_32; end; rel.info:=(relsym shl 8) or reltyp; { write reloc } s.relocsect.write(rel,sizeof(rel)); r:=TAsmRelocation(r.next); end; end; end; procedure telf32objectoutput.createsymtab; var elfsym : telf32symbol; sec : TSection; locals : longint; sym : tasmsymbol; begin with elf32data do begin locals:=2; { empty entry } fillchar(elfsym,sizeof(elfsym),0); symtabsect.write(elfsym,sizeof(elfsym)); { filename entry } elfsym.st_name:=1; elfsym.st_info:=STT_FILE; elfsym.st_shndx:=SHN_ABS; symtabsect.write(elfsym,sizeof(elfsym)); { section } for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) then begin fillchar(elfsym,sizeof(elfsym),0); elfsym.st_name:=telf32section(sects[sec]).shstridx; elfsym.st_info:=STT_SECTION; elfsym.st_shndx:=telf32section(sects[sec]).secshidx; symtabsect.write(elfsym,sizeof(elfsym)); inc(locals); end; { symbols } sym:=Tasmsymbol(symbols.First); while assigned(sym) do begin fillchar(elfsym,sizeof(elfsym),0); { symbolname, write the #0 separate to overcome 255+1 char not possible } elfsym.st_name:=strtabsect.datasize; strtabsect.writestr(sym.name); strtabsect.writestr(#0); case sym.currbind of AB_LOCAL, AB_GLOBAL : elfsym.st_value:=sym.address; AB_COMMON : elfsym.st_value:=$10; end; elfsym.st_size:=sym.size; case sym.currbind of AB_LOCAL : begin elfsym.st_info:=STB_LOCAL shl 4; inc(locals); end; AB_COMMON, AB_EXTERNAL, AB_GLOBAL : elfsym.st_info:=STB_GLOBAL shl 4; end; if sym.currbind<>AB_EXTERNAL then begin case sym.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 sym.currbind=AB_COMMON then elfsym.st_shndx:=SHN_COMMON else if assigned(sects[sym.section]) then elfsym.st_shndx:=telf32section(sects[sym.section]).secshidx else elfsym.st_shndx:=SHN_UNDEF; symtabsect.write(elfsym,sizeof(elfsym)); sym:=tasmsymbol(sym.indexnext); end; { update the .symtab section header } symtabsect.shlink:=strtabsect.secshidx; symtabsect.shinfo:=locals; end; end; procedure telf32objectoutput.createshstrtab; var sec : TSection; begin with elf32data do begin with shstrtabsect do begin writestr(#0); symtabsect.shstridx:=writestr('.symtab'#0); strtabsect.shstridx:=writestr('.strtab'#0); shstrtabsect.shstridx:=writestr('.shstrtab'#0); for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) then begin telf32section(sects[sec]).shstridx:=writestr(sects[sec].name+#0); if assigned(telf32section(sects[sec]).relocsect) then telf32section(sects[sec]).relocsect.shstridx:=writestr(telf32section(sects[sec]).relocsect.name+#0); end; end; end; end; procedure telf32objectoutput.writesectionheader(s:telf32section); var sechdr : telf32sechdr; 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.datasize; sechdr.sh_link:=s.shlink; sechdr.sh_info:=s.shinfo; sechdr.sh_addralign:=s.addralign; sechdr.sh_entsize:=s.entsize; writer.write(sechdr,sizeof(sechdr)); end; function telf32objectoutput.writedata(data:TAsmObjectData):boolean; var header : telf32header; datapos, shoffset, nsects : longint; hstab : telf32stab; sec : TSection; empty : array[0..63] of byte; hp : pdynamicblock; begin result:=false; elf32data:=telf32objectdata(data); with elf32data do begin { calc amount of sections we have } fillchar(empty,sizeof(empty),0); nsects:=1; initsym:=2; for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) then begin { each section requires a symbol for relocation } sects[sec].secsymidx:=initsym; inc(initsym); { also create the index in the section header table } telf32section(sects[sec]).secshidx:=nsects; inc(nsects); if sects[sec].relocations.count>0 then inc(nsects); end; { add default sections follows } shstrtabsect.secshidx:=nsects; inc(nsects); symtabsect.secshidx:=nsects; inc(nsects); strtabsect.secshidx:=nsects; inc(nsects); { For the stab section we need an HdrSym which can now be calculated more easily } if assigned(sects[sec_stab]) then begin hstab.strpos:=1; hstab.ntype:=0; hstab.nother:=0; hstab.ndesc:=(sects[sec_stab].datasize div sizeof(telf32stab))-1{+1 according to gas output PM}; hstab.nvalue:=sects[sec_stabstr].datasize; sects[sec_stab].Data.seek(0); sects[sec_stab].Data.write(hstab,sizeof(hstab)); end; { Create the relocation sections } for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) and (sects[sec].relocations.count>0) then createrelocsection(telf32section(sects[sec])); { create .symtab and .strtab } createsymtab; { create .shstrtab } createshstrtab; { Calculate the filepositions } datapos:=$40; { elfheader + alignment } { sections first } for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) then begin sects[sec].datapos:=datapos; if assigned(sects[sec].data) then inc(datapos,sects[sec].aligneddatasize); end; { shstrtab } shstrtabsect.datapos:=datapos; inc(datapos,shstrtabsect.aligneddatasize); { section headers } shoffset:=datapos; inc(datapos,nsects*sizeof(telf32sechdr)); { symtab } symtabsect.datapos:=datapos; inc(datapos,symtabsect.aligneddatasize); { strtab } strtabsect.datapos:=datapos; inc(datapos,align(strtabsect.datasize,4)); { .rel sections } for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) and assigned(telf32section(sects[sec]).relocsect) then begin telf32section(sects[sec]).relocsect.datapos:=datapos; inc(datapos,telf32section(sects[sec]).relocsect.aligneddatasize); end; { Write ELF Header } fillchar(header,sizeof(header),0); header.magic0123:=$464c457f; { = #127'ELF' } header.file_class:=1; header.data_encoding:=1; header.file_version:=1; header.e_type:=1; header.e_machine:=3; header.e_version:=1; header.e_shoff:=shoffset; header.e_shstrndx:=shstrtabsect.secshidx; header.e_shnum:=nsects; header.e_ehsize:=sizeof(telf32header); header.e_shentsize:=sizeof(telf32sechdr); writer.write(header,sizeof(header)); writer.write(empty,$40-sizeof(header)); { align } { Sections } for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) and assigned(sects[sec].data) then begin sects[sec].alignsection; hp:=sects[sec].Data.firstblock; while assigned(hp) do begin writer.write(hp^.data,hp^.used); hp:=hp^.next; end; end; { .shstrtab } shstrtabsect.alignsection; hp:=shstrtabsect.Data.firstblock; while assigned(hp) do begin writer.write(hp^.data,hp^.used); hp:=hp^.next; end; { section headers, start with an empty header for sh_undef } writer.write(empty,sizeof(telf32sechdr)); for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) then begin writesectionheader(telf32section(sects[sec])); if assigned(telf32section(sects[sec]).relocsect) then writesectionheader(telf32section(sects[sec]).relocsect); end; writesectionheader(shstrtabsect); writesectionheader(symtabsect); writesectionheader(strtabsect); { .symtab } symtabsect.alignsection; hp:=symtabsect.Data.firstblock; while assigned(hp) do begin writer.write(hp^.data,hp^.used); hp:=hp^.next; end; { .strtab } strtabsect.writealign(4); hp:=strtabsect.Data.firstblock; while assigned(hp) do begin writer.write(hp^.data,hp^.used); hp:=hp^.next; end; { .rel sections } for sec:=low(TSection) to high(TSection) do if assigned(sects[sec]) and assigned(telf32section(sects[sec]).relocsect) then begin telf32section(sects[sec]).relocsect.alignsection; hp:=telf32section(sects[sec]).relocsect.Data.firstblock; while assigned(hp) do begin writer.write(hp^.data,hp^.used); hp:=hp^.next; end; end; end; result:=true; end; {**************************************************************************** TELFAssembler ****************************************************************************} constructor TELF32Assembler.Create(smart:boolean); begin inherited Create(smart); objectoutput:=telf32objectoutput.create(smart); end; {***************************************************************************** Initialize *****************************************************************************} const as_i386_elf32_info : tasminfo = ( id : as_i386_elf32; idtxt : 'ELF'; asmbin : ''; asmcmd : ''; supported_target : system_any; //target_i386_linux; outputbinary : true; allowdirect : false; needar : false; labelprefix_only_inside_procedure: false; labelprefix : '.L'; comment : ''; secnames : ('', '.text','.data','.bss', '.idata$2','.idata$4','.idata$5','.idata$6','.idata$7','.edata', '.stab','.stabstr','') ); initialization RegisterAssembler(as_i386_elf32_info,TElf32Assembler); end. { $Log$ Revision 1.19 2003-04-22 14:33:38 peter * removed some notes/hints Revision 1.18 2002/08/12 15:08:39 carl + stab register indexes for powerpc (moved from gdb to cpubase) + tprocessor enumeration moved to cpuinfo + linker in target_info is now a class * many many updates for m68k (will soon start to compile) - removed some ifdef or correct them for correct cpu Revision 1.17 2002/07/26 21:15:39 florian * rewrote the system handling Revision 1.16 2002/07/01 18:46:24 peter * internal linker * reorganized aasm layer Revision 1.15 2002/05/18 13:34:10 peter * readded missing revisions Revision 1.14 2002/05/16 19:46:39 carl + defines.inc -> fpcdefs.inc to avoid conflicts if compiling by hand + try to fix temp allocation (still in ifdef) + generic constructor calls + start of tassembler / tmodulebase class cleanup Revision 1.12 2002/05/12 16:53:08 peter * moved entry and exitcode to ncgutil and cgobj * foreach gets extra argument for passing local data to the iterator function * -CR checks also class typecasts at runtime by changing them into as * fixed compiler to cycle with the -CR option * fixed stabs with elf writer, finally the global variables can be watched * removed a lot of routines from cga unit and replaced them by calls to cgobj * u32bit-s32bit updates for and,or,xor nodes. When one element is u32bit then the other is typecasted also to u32bit without giving a rangecheck warning/error. * fixed pascal calling method with reversing also the high tree in the parast, detected by tcalcst3 test Revision 1.11 2002/04/04 19:05:58 peter * removed unused units * use tlocation.size in cg.a_*loc*() routines }