Re: contributor guidelines

[Jonathan Wakely <jwakely.gcc@gmail.com>]

On Mon, 4 Dec 2023 at 12:19, Bruno Haible wrote:
>
> Hi,
>
> I was asked to post a patch for a bugzilla PR to gcc-patches@. Two questions
> regarding https://gcc.gnu.org/contribute.html#testing :
>
> 1) This web page says:
>    "For a normal native configuration, running
>
>       make bootstrap
>       make -k check
>
>     from the top level of the GCC tree (not the gcc subdirectory) will
>     accomplish this."
>
> But what I get, from a git checkout of the GCC tree:
>
>   $ make bootstrap
>   make: *** No rule to make target 'bootstrap'.  Stop.
>
> I think the instructions should be amended to read:
>
>       ./configure [options]
>       make bootstrap
>       make -k check
>
> Right?

No, don't configure in the source directory:
https://gcc.gnu.org/wiki/FAQ#configure

But otherwise yes, the fact you need to configure before running make
is so obvious that apparently we took it for granted :-)

And it hasn't been necessary to run 'make bootstrap' for years, just
running 'make' does exactly the same thing now.

>
> 2) That's what I did:
>
> $ ./configure --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu --prefix=/arch/x86_64-linux-gnu/gnu-inst-gcc/testing --enable-shared --enable-nls --enable-threads=posix --enable-__cxa_atexit --disable-multilib --with-as=/arch/x86_64-linux-gnu/gnu-inst-binutils/2.38/bin/as --with-ld=/arch/x86_64-linux-gnu/gnu-inst-binutils/2.38/bin/ld --with-gmp=/arch/x86_64-linux-gnu/gnu-inst-gcc/testing --with-mpfr=/arch/x86_64-linux-gnu/gnu-inst-gcc/testing --with-mpc=/arch/x86_64-linux-gnu/gnu-inst-gcc/testing --with-isl=/arch/x86_64-linux-gnu/gnu-inst-gcc/testing --enable-languages=c,c++,objc,obj-c++,lto,jit,fortran,go,d,m2 --enable-host-shared 2>&1 | tee log0

This seems unnecessarily overcomplicated. Most of those options are
just restating the defaults.


> $ make bootstrap 2>&1 | tee log1
>
> and it fails like this:
>
> /GCC/gcc/host-x86_64-pc-linux-gnu/gcc/xgcc -B/GCC/gcc/host-x86_64-pc-linux-gnu/gcc/ -B/arch/x86_64-linux-gnu/gnu-inst-gcc/testing/x86_64-pc-linux-gnu/bin/ -B/arch/x86_64-linux-gnu/gnu-inst-gcc/testing/x86_64-pc-linux-gnu/lib/ -isystem /arch/x86_64-linux-gnu/gnu-inst-gcc/testing/x86_64-pc-linux-gnu/include -isystem /arch/x86_64-linux-gnu/gnu-inst-gcc/testing/x86_64-pc-linux-gnu/sys-include   -fno-checking -g -O2 -O2  -g -O2 -DIN_GCC   -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wno-format -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition  -isystem ./include  -fpic -mlong-double-80 -DUSE_ELF_SYMVER -fcf-protection -mshstk -g -DIN_LIBGCC2 -fbuilding-libgcc -fno-stack-protector  -fpic -mlong-double-80 -DUSE_ELF_SYMVER -fcf-protection -mshstk -I. -I. -I../../host-x86_64-pc-linux-gnu/gcc -I../.././libgcc -I../.././libgcc/. -I../.././libgcc/../gcc -I../.././libgcc/../include -I../.././libgcc/config/libbid -DENABLE_DECIMAL_BID_FORMAT -DHAVE_CC_TLS  -DUSE_TLS  -o bid128_add.o -MT bid128_add.o -MD -MP -MF bid128_add.dep -c ../.././libgcc/config/libbid/bid128_add.c
> during RTL pass: expand
> ../.././libgcc/config/libbid/bid128_add.c: In function ‘__bid128_add’:
> ../.././libgcc/config/libbid/bid128_add.c:637:42: internal compiler error: Aborted
>   637 |       else if (rnd_mode == ROUNDING_DOWN && x_sign != y_sign)
> 0x178a410 crash_signal
>         ../.././gcc/toplev.cc:316

I don't see this error when building master on x86_64-pc-linux-gnu.
This might be a local problem, caused by your host compiler, or the
versions of GMP, MPFR, or MPC, or something else.


> I am surprised to see such a failure, since x86_64-linux-gnu is the most
> common platform.
>
> What am I supposed to do?
>   - Use the latest release tag (13.2.0) instead of the tip of 'master',
>     and test my contribution there?
>   - Wait a few days, do a 'git pull', and retry?
>   - Something else?