37 lines
1.5 KiB
Nix
37 lines
1.5 KiB
Nix
{ lib
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, stdenv
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}:
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# Trick to build a gcc that is capable of emitting shared libraries *without* having the
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# targetPlatform libc available beforehand. Taken from:
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# https://web.archive.org/web/20170222224855/http://frank.harvard.edu/~coldwell/toolchain/
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# https://web.archive.org/web/20170224235700/http://frank.harvard.edu/~coldwell/toolchain/t-linux.diff
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let
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# crt{i,n}.o are the first and last (respectively) object file
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# linked when producing an executable. Traditionally these
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# files are delivered as part of the C library, but on GNU
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# systems they are in fact built by GCC. Since libgcc needs to
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# build before glibc, we can't wait for them to be copied by
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# glibc. At this early pre-glibc stage these files sometimes
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# have different names.
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crtstuff-ofiles =
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if stdenv.targetPlatform.isPower
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then "ecrti.o ecrtn.o ncrti.o ncrtn.o"
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else "crti.o crtn.o";
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# Normally, `SHLIB_LC` is set to `-lc`, which means that
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# `libgcc_s.so` cannot be built until `libc.so` is available.
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# The assignment below clobbers this variable, removing the
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# `-lc`.
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#
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# On PowerPC we add `-mnewlib`, which means "libc has not been
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# built yet". This causes libgcc's Makefile to use the
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# gcc-built `{e,n}crt{n,i}.o` instead of failing to find the
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# versions which have been repackaged in libc as `crt{n,i}.o`
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#
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SHLIB_LC = lib.optionalString stdenv.targetPlatform.isPower "-mnewlib";
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in ''
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echo 'libgcc.a: ${crtstuff-ofiles}' >> libgcc/Makefile.in
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echo 'SHLIB_LC=${SHLIB_LC}' >> libgcc/Makefile.in
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''
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