Re: [Qemu-devel] [PULL v2 1/4] build: Use $(CCAS) for compiling .S files

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <rth@twiddle.net> writes:

> We fail to pass to $(AS) all of the different flags that may be required
> for a given set of CFLAGS.  Rather than figuring out the host-specific
> mapping, it's better to allow the compiler driver to do that.
>
> However, simply using $(CC) runs afoul of clang trying to build the
> option roms.  C.f. 3dd46c78525a30e98c68, wherein we changed from
> using $(CC) to using $(AS) in the first place.
>
> Work around this by passing -fno-integrated-as to clang, so that we use
> the external assembler, and the clang driver still passes along all of
> the options that the assembler might require.
>
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> Message-Id: <1466703558-7723-1-git-send-email-rth@twiddle.net>
> ---
>  configure | 13 ++++++++++---
>  rules.mak |  7 ++-----
>  2 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/configure b/configure
> index 67beb47..e9090a0 100755
> --- a/configure
> +++ b/configure
> @@ -368,7 +368,7 @@ else
>  fi
>
>  ar="${AR-${cross_prefix}ar}"
> -as="${AS-${cross_prefix}as}"
> +ccas="${CCAS-$cc}"
>  cpp="${CPP-$cc -E}"
>  objcopy="${OBJCOPY-${cross_prefix}objcopy}"
>  ld="${LD-${cross_prefix}ld}"
> @@ -4490,6 +4490,13 @@ if test "$fortify_source" != "no"; then
>    fi
>  fi
>
> +#################################################
> +# clang does not support the 16-bit assembly for roms
> +
> +if echo | $ccas -dM -E - | grep __clang__ > /dev/null 2>&1 ; then
> +  ccas="$ccas -fno-integrated-as"
> +fi

Hi Richard,

This looks like it breaks the Travis clang:

    https://travis-ci.org/qemu/qemu/builds/142825178

We get the error:

    AS    optionrom/multiboot.o
    clang: error: unknown argument: '-fno-integrated-as'
    make[1]: *** [multiboot.o] Error 1
    make: *** [romsubdir-optionrom] Error 2
    make: *** Waiting for unfinished jobs....

Clang in Travis is:

    clang version 3.4 (tags/RELEASE_34/final)

> +
>  ##########################################
>  # check if struct fsxattr is available via linux/fs.h
>
> @@ -5508,7 +5515,7 @@ echo "CXX=$cxx" >> $config_host_mak
>  echo "OBJCC=$objcc" >> $config_host_mak
>  echo "AR=$ar" >> $config_host_mak
>  echo "ARFLAGS=$ARFLAGS" >> $config_host_mak
> -echo "AS=$as" >> $config_host_mak
> +echo "CCAS=$ccas" >> $config_host_mak
>  echo "CPP=$cpp" >> $config_host_mak
>  echo "OBJCOPY=$objcopy" >> $config_host_mak
>  echo "LD=$ld" >> $config_host_mak
> @@ -5981,7 +5988,7 @@ for rom in seabios vgabios ; do
>      config_mak=roms/$rom/config.mak
>      echo "# Automatically generated by configure - do not modify" > $config_mak
>      echo "SRC_PATH=$source_path/roms/$rom" >> $config_mak
> -    echo "AS=$as" >> $config_mak
> +    echo "CCAS=$ccas" >> $config_mak
>      echo "CC=$cc" >> $config_mak
>      echo "BCC=bcc" >> $config_mak
>      echo "CPP=$cpp" >> $config_mak
> diff --git a/rules.mak b/rules.mak
> index 72c5955..7d7d83b 100644
> --- a/rules.mak
> +++ b/rules.mak
> @@ -68,11 +68,8 @@ LINK = $(call quiet-command, $(LINKPROG) $(QEMU_CFLAGS) $(CFLAGS) $(LDFLAGS) -o
>         $(call process-archive-undefs, $1) \
>         $(version-obj-y) $(call extract-libs,$1) $(LIBS),"  LINK  $(TARGET_DIR)$@")
>
> -%.asm: %.S
> -	$(call quiet-command,$(CPP) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -o $@ $<,"  CPP   $(TARGET_DIR)$@")
> -
> -%.o: %.asm
> -	$(call quiet-command,$(AS) $(ASFLAGS) -o $@ $<,"  AS    $(TARGET_DIR)$@")
> +%.o: %.S
> +	$(call quiet-command,$(CCAS) $(QEMU_INCLUDES) $(QEMU_CFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) -c -o $@ $<,"  AS    $(TARGET_DIR)$@")
>
>  %.o: %.cc
>  	$(call quiet-command,$(CXX) $(QEMU_INCLUDES) $(QEMU_CXXFLAGS) $(QEMU_DGFLAGS) $(CFLAGS) $($@-cflags) -c -o $@ $<,"  CXX   $(TARGET_DIR)$@")


--
Alex Bennée