Hi,
because all the Makefiles and such historically mess with CFLAGS and such, T2
is using those gcc wrapper to automatically filter the options.
The wrappers therefore by default remove other -m* opts and inject what is
configured in T2 (as you ask for pentium4).
If you want chromium to mess with the compiler options you could set
GCC_WRAPPER_BYPASS=1 or remove the -m* options from the GCC_WRAPPER_REMOVE list.
Btw. do you plan to chafe the chromium package you are working on? ;-)
René
On 08 Jan 2018, at 21:55, Toan Pham <[email protected]> wrote:
>
>
>
> Rene,
>
> I am working on building chromium webengine w/ a t2 compiler that was
> configured and optimized for pentium4. The detail of the compile is shown at
> the end of this email, version 4.8.5 w/o support for SSE3>= and AVX and AVX2.
> The problem I am having is that Chromium (libvpx) requires that the compiler
> to support AVX+AVX2, so that those features can detected at build-time and
> runtime. I've tried to reconfigured gcc wrapper (see below) to support a
> newer architecture in hope that the compiler would be able to build AVX+AVX2
> instructions; however, compile still failed to recognize/compile AVX assembly
> code.
>
>
> GCC_WRAPPER_DEBUG=1 GCC_WRAPPER_INSERT="-march=corei7 -mtune=corei7 -Os
> -mssse3 -mavx -mavx2 -mpreferred-stack-boundary=7"
> GCC_WRAPPER_REMOVE="-I/usr/local/include -I/usr/include -O -O[0-9s] -mtune*
> -march* -mcpu* -Werror -g*" GCC_WRAPPER_APPEND="-s
> */X11R6/include?-I/usr/X11R7/include */X11R6/lib?-L/usr/X11R7/lib
> */X11R6/lib64?-L/usr/X11R7/lib -mavx -mavx2" make
>
>
> My question to you is that: is it true that once GCC is built w/ option
> "-with-arch=pentium4", it is not possible to tell gcc to build machine code
> for higher architectures with updated cflags like "-march=corei7
> -mtune=corei7 -mavx -mavx2"? If the answer is yes, then pretty much a new
> 'generic i686' compiler is needed to build chromium.
>
> Thanks,
>
> TP
>
>
>
> debug-linux26:[webengine]# gcc -v
> Using built-in specs.
> COLLECT_GCC=gcc
> COLLECT_LTO_WRAPPER=/usr/libexec/gcc/i686-t2-linux-gnu/4.8.5/lto-wrapper
> Target: i686-t2-linux-gnu
> Configured with: ../configure --prefix=/usr --bindir=/usr/bin
> --sbindir=/usr/sbin --libdir=/usr/lib --datadir=/usr/share
> --includedir=/usr/include --infodir=/usr/info --mandir=/usr/man
> --sysconfdir=/etc --localstatedir=/var --disable-debug --with-libpam
> --with-pam --enable-libpam --enable-pam --with-mysql-lib=/usr/lib/mysql
> --with-mysql-include=/usr/include/mysql --with-mysql-lib=/usr/lib/mysql
> --with-mysql-include=/usr/include/mysql --build=i686-t2-linux-gnu
> --host=i686-t2-linux-gnu --target=i686-t2-linux-gnu
> --enable-install-libiberty=no --disable-install-libiberty
> --with-arch=pentium4 --with-arch=pentium4 --enable-__cxa_atexit
> --disable-checking --disable-bootstrap --disable-libstdcxx-pch
> --disable-multilib --disable-target-libiberty --with-gnu-as --with-gnu-ld
> --enable-threads=posix --enable-languages=c,c++,objc,go --enable-shared
> Thread model: posix
>
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