Thank you VERY much for the reply. See below for comments please. On 17 Jan 2003, Nick Clifton wrote:
> > I think the "correct" way to handle this is to implement the secrel psuedo > > op like IA64 does. I only have a very vauge idea what this means. > > > > Can a binutils guru enlighten me on what's involved here? Thanks. > > I'll try. Basically you change gcc so that instead of generating: > > .word <value> > > it generates something like this: > > .word <value> @secrel (<label>) > > for a DWARF2 section-relative relocation. Done and easy. > The exact syntax you choose is up to you, and presumably you would > choose something that fits in with current x86 assembler syntax. > I am searching the net trying to figure that out. I am not very experienced in x86 or Windows, so if anyone knows, please speak up. > Then you extend the x86 backend in GAS (file: gas/config/tc-i386.c) so > that it can parse the new syntax and generate a relocation for the > value. In fact you will probably need a set of relocations to handle > different sized values (ie 8-bit, 16-bit, 32-bit and 64-bit). > This is where it starts getting really messy, for me at least. No. I only need 32-bit, as that is all the i386 PE format specifies, and it is all dwarf2 needs. > GAS actually creates relocations by a two stage process. First it > creates a 'fixup' which is a structure describing an area of the > to-be-output binary that will need extra processing once it has > finished its pass of the input source file(s). Then it processes > these fixups, creating relocations if necessary. > > To add new x86 relocation numbers you will need to modify > include/elf/i386.h and bfd/reloc.c. (After which you will need to run > "make headers" in the bfd build directory to recreate the other header > files). You will then need to extend the bfd/elf32-i386.c source file > to handle your new relocations. > Just to clarify, this PE/coff, not elf. So, include/coff/internal.h and bfd/coff-i386.c are the relevant files. Is BFD_RELOC_32_BASEREL appropriate here? If so, I do not need to modify bfd/reloc.c. > Of course there is no real documentation on how to do any of this, so > the source code is still the best guide. As you have found the IA64 > port has done this already, so you can use that as your guide. > Since they did it for elf, not coff, it seems to be a very loose guide. Also, it seams every port has their own way of doing things. There is a lot of port specific code that looks like it should have been shared. Just more confusion for me :). > Finally you should create an assembler test case to make sure that the > assembler and disassembler can handle these new pseudo ops and > relocations. > I look into that. Thanks. -- Brian Ford Senior Realtime Software Engineer VITAL - Visual Simulation Systems FlightSafety International Phone: 314-551-8460 Fax: 314-551-8444 -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Bug reporting: http://cygwin.com/bugs.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
