Re: Building Native ToolChain (SH3)

[Mike Frysinger <vapier at gentoo dot org>]

On Saturday 13 August 2005 12:16 am, Dan Kegel wrote:
> Mike Frysinger wrote:
> >>Have you read the last paragraph of
> >>http://kegel.com/crosstool/crosstool-0.38/doc/crosstool-howto.html#canadi
> >>an which mentions you need to edit the resulting spec file?
> >
> > heh, that fixed the issue on my end ... `gcc -print-search-dirs` now
> > includes /usr/lib and /lib ...
> >
> > what about gcc-4.x then ?  iirc, they're getting away from external
> > spec's, so this wont be fixable in the same way right ?

dont quote me on that, i just vaguely remember hearing about it and if i check 
my local gcc-4.0.0 / gcc-4.0.1 installs, i dont have a 'specs' file like i do 
with gcc-3.3.[56] and gcc-3.4.[34] ...

> I guess it'll take a little looking at the code to see
> where it gets the value from now, and fix it there instead.
> Anyone feel like looking?  (Or asking the experts?)

anytime i ask experts i just look like a dumbass :D

for those who dont want to read below, the short answer is:
gcc-3.x installs a broken specs file but the binary itself is OK which means 
since gcc-4.x doesnt install a default specs file, it should work even better 
out of the box ...

now on to the brain dump:

gcc/gcc.c has this:
#ifdef CROSS_COMPILE
static const char *cross_compile = "1";
#else
static const char *cross_compile = "0";
#endif

CROSS_COMPILE comes from gcc/configure.ac:
CROSS=                      AC_SUBST(CROSS)
...
if test x$host != x$target
then
    CROSS="-DCROSS_COMPILE"

but as we can see, a canadian cross shouldnt trigger this ... nor does it if 
we run `gcc -dumpspecs` on the target host after deleting the local specs 
file ... however, the generated gcc/specs file after running `make` certainly 
has cross_compile set to 1 ...

gcc/Makefile.in has this target:
# Dump a specs file to make -B./ read these specs over installed ones.
$(SPECS): xgcc$(exeext)
    $(GCC_FOR_TARGET) -dumpspecs > tmp-specs
    mv tmp-specs $(SPECS)

i havent tested this bit, but it sounds like the cross gcc that is being used 
to build the target gcc is having *its* specs dumped which would explain why 
the installed specs file reports itself as a cross-compiler ...

i guess what this all means is that specs building with gcc-3.x is broken 
unless we add a small tweak here which would fix tmp-specs before moving it 
to $(SPECS) ... but since the compiled gcc has the correct value encoded in 
it, gcc-4.x should be fine
-mike

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