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x86_64 internal ELF linker:

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* Split generation of regular and TLSIE GOT entries. Although code for both is similar to some extent, mixing them in a single method turns it into spaghetti.
* Several fixes to content and dynamic relocations of TLSIE entries.

git-svn-id: trunk@25180 -
This commit is contained in:
sergei 2013-07-29 08:34:00 +00:00
parent db0585f388
commit 11b72b5515
1 changed files with 55 additions and 19 deletions
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74
compiler/x86_64/cpuelf.pas
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@ -35,7 +35,8 @@ implementation
type
TElfExeOutputx86_64=class(TElfExeOutput)
private
procedure MaybeWriteGOTEntry(reltyp:byte;relocval:aint;objsym:TObjSymbol);
procedure MaybeWriteGOTEntry(relocval:aint;objsym:TObjSymbol);
procedure MaybeWriteTLSIEGotEntry(relocval:aint;objsym:TObjSymbol);
protected
procedure WriteFirstPLTEntry;override;
procedure WritePLTEntry(exesym:TExeSymbol);override;
@ -260,7 +261,7 @@ implementation
ReportNonDSOReloc(reltyp,objsec,objreloc);
{ R_X86_64_32 is processed by rtld, but binutils accept it in data sections only.
Relocating the against local symbols is tricky: changing into RELATIVE is not possible,
Relocating against local symbols is tricky: changing into RELATIVE is not possible,
so it is changed into relocation against section symbol. This requires adding
the appropriate section symbol to dynamic symtable. BFD also has some obscure logic
behind, e.g. it uses .text section for symbols from .data section.
@ -320,7 +321,7 @@ implementation
end;
procedure TElfExeOutputx86_64.MaybeWriteGOTEntry(reltyp:byte;relocval:aint;objsym:TObjSymbol);
procedure TElfExeOutputx86_64.MaybeWriteGOTEntry(relocval:aint;objsym:TObjSymbol);
var
gotoff,tmp:aword;
begin
@ -334,18 +335,43 @@ implementation
begin
gotobjsec.write(relocval,sizeof(pint));
tmp:=gotobjsec.mempos+gotoff-sizeof(pint);
if (objsym.exesymbol.dynindex>0) then
dynreloclist.Add(TObjRelocation.CreateRaw(tmp,objsym,R_X86_64_GLOB_DAT))
else
if IsSharedLibrary then
WriteDynRelocEntry(tmp,R_X86_64_RELATIVE,0,relocval);
end;
end;
procedure TElfExeOutputx86_64.MaybeWriteTLSIEGotEntry(relocval:aint;objsym:TObjSymbol);
var
gotoff,tmp: aword;
objrel: TObjRelocation;
begin
gotoff:=objsym.exesymbol.gotoffset;
if gotoff=0 then
InternalError(2012060903);
if gotoff=gotobjsec.Data.size+sizeof(pint) then
begin
tmp:=gotobjsec.mempos+gotoff-sizeof(pint);
if (objsym.exesymbol.dynindex>0) then
begin
if (reltyp=R_X86_64_GOTTPOFF) then
if IsSharedLibrary then
dynreloclist.Add(TObjRelocation.CreateRaw(tmp,objsym,R_X86_64_TPOFF64)) // probably incorrect
else
else
dynreloclist.Add(TObjRelocation.CreateRaw(tmp,objsym,R_X86_64_GLOB_DAT));
gotobjsec.writezeros(sizeof(pint));
dynreloclist.Add(TObjRelocation.CreateRaw(tmp,objsym,R_X86_64_TPOFF64));
end
else if IsSharedLibrary then
WriteDynRelocEntry(tmp,R_X86_64_RELATIVE,0,relocval);
else
begin
gotobjsec.write(relocval,sizeof(pint));
if IsSharedLibrary then
begin
objrel:=TObjRelocation.CreateRaw(tmp,nil,R_X86_64_TPOFF64);
objrel.orgsize:=relocval;
dynreloclist.Add(objrel);
end;
end;
end;
end;
@ -434,8 +460,8 @@ implementation
//R_X86_64_DTPOFF64 is possible in data??
R_X86_64_DTPOFF32:
begin
{ In executable it behaves as TPOFF32, but data expressions
like ".long foo@dtpoff" resolve to positive offset }
{ In executable it behaves as TPOFF32 (i.e. generates negative offset),
but data expressions like ".long foo@dtpoff" resolve to positive offset }
if IsSharedLibrary or not (oso_executable in objsec.SecOptions) then
address:=address+relocval-tlsseg.MemPos
else
@ -446,14 +472,24 @@ implementation
R_X86_64_TPOFF64:
address:=address+relocval-(tlsseg.MemPos+tlsseg.MemSize);
R_X86_64_GOTTPOFF,
R_X86_64_GOTTPOFF:
begin
if IsSharedLibrary then
relocval:=relocval-tlsseg.MemPos
else
relocval:=relocval-(tlsseg.MemPos+tlsseg.MemSize);
MaybeWriteTLSIEGotEntry(relocval,objreloc.symbol);
{ resolves to PC-relative offset to GOT slot }
relocval:=gotobjsec.mempos+objreloc.symbol.exesymbol.gotoffset-sizeof(pint);
address:=address+relocval-PC;
end;
R_X86_64_GOTPCREL,
R_X86_64_GOTPCREL64:
begin
if (reltyp=R_X86_64_GOTTPOFF) then
relocval:=relocval-(tlsseg.MemPos+tlsseg.MemSize);
MaybeWriteGOTEntry(reltyp,relocval,objreloc.symbol);
MaybeWriteGOTEntry(relocval,objreloc.symbol);
{ resolves to PC-relative offset to GOT slot }
relocval:=gotobjsec.mempos+objreloc.symbol.exesymbol.gotoffset-sizeof(pint);
@ -488,7 +524,7 @@ implementation
R_X86_64_GOT32,
R_X86_64_GOT64:
begin
MaybeWriteGOTEntry(reltyp,relocval,objreloc.symbol);
MaybeWriteGOTEntry(relocval,objreloc.symbol);
relocval:=gotobjsec.mempos+objreloc.symbol.exesymbol.gotoffset-sizeof(pint)-gotsymbol.address;
address:=address+relocval;