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34229 |
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08-Mar-1998 |
peter |
First round of changes to support generation of assembler for the old a.out gas and the binutils gas (elf or a.out) with a single compiler.
This uses other infrastructure not yet committed, in order to support both a.out and elf it needs to be able to get to both a.out and elf gas, ld, libs, crt* etc. So for now, the support is pretty much dormant.
The new freebsd.h file is based on the old freebsd-elf.h file (which has a long lineage, right back through linux and svr4 files). The change is pretty dramatic from a gcc internals standpoint as it overrides a lot of definitions in order to generate different output based on target mode. There is potential for screw-ups, so please be on the lookout - gcc's configuration mechanism wasn't really meant for this kind of thing. It's believed to compile world etc just fine under both a.out and elf, can handle global constructors and destructors, handles the differences in a.out and elf stabs, and what sections things like exceptions go in.
The initial idea came from i386/osfrose.h which is a dual rose/elf format target. These two are not as diverse as a.out and elf it would seem.
The cc front-end uses external configuration to determine default object format (still being thrashed out, so read the source if you want to see it so far), and has a '-aout' and '-elf' override command line switch. There are some other internal switches that can be accessed, namely -maout, -mno-aout, -munderscores and -mnounderscores. The underscore and local symbol prefixing rules are controllable seperately to the output format. (ie: it's possible to generate a.out without the _ prefixes on symbols and also to generate elf with the _ prefixes. This isn't quite optimal, but does seem to work pretty well, except the linkers don't always recognise the local symbols without their normal names)
The default format is a.out (still), nobody should see any major changes.
With both elf and a.out tools and libraries installed:
[1:26pm]/tmp-223> cc -elf -o hello hello.c peter@beast[1:27pm]/tmp-224> file hello hello: ELF 32-bit LSB executable, Intel 80386, version 1 (FreeBSD), dynamically linked, not stripped [1:27pm]/tmp-225> ./hello hello world!
[1:27pm]/tmp-226> cc -aout -o hello hello.c [1:27pm]/tmp-227> file hello hello: FreeBSD/i386 compact demand paged dynamically linked executable not stripped 1:27pm]/tmp-228> ./hello hello world!
Since my co-conspirators put a lot of effort into this too, I'll add them so they can share the blame^H^H^H^H^Hglory. :-)
Reviewed by: sos, jdp
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#
18659 |
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03-Oct-1996 |
jdp |
Fix a bug that caused incorrect PIC code to be generated for exceptions. The symptom was an assembler warning
"GOT relocation burb: `___EXCEPTION_TABLE__' should be global"
followed (sometimes) by a core dump. The fix makes the compiler generate the correct GOTOFF addressing for that symbol, rather than the GOT addressing it was emitting before.
Warning: There is still at least one serious bug in the i386 exception code for PIC. The exception code that is generated clobbers the GOT register (%ebx) and then tries to use it later. That leads to core dumps at program execution time. I know where the problem is, but I do not have a fix for it at this time. Until it is fixed, exceptions will not work in PIC code. This is a general problem for all i386 platforms; it is not specific to FreeBSD.
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#
18334 |
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18-Sep-1996 |
peter |
Import of unmodified (but trimmed) gcc-2.7.2. The bigger parts of the non-i386, non-unix, and generatable files have been trimmed, but can easily be added in later if needed.
gcc-2.7.2.1 will follow shortly, it's a very small delta to this and it's handy to have both available for reference for such little cost.
The freebsd-specific changes will then be committed, and once the dust has settled, the bmakefiles will be committed to use this code.
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