RE: Two build != host fixes

[Bernd Edlinger <bernd dot edlinger at hotmail dot de>]

On Wed, 11 Dec 2013 23:11:46, Alan Modra wrote:
>
> On Wed, Dec 11, 2013 at 12:10:04PM +0100, Bernd Edlinger wrote:
>> Hi,
>>
>> I'm having problems with that patch.
>
> Sorry to hear that.
>

Never mind.

I have similar patches, but I did not 
>> I try to start at X86_64-linux-gnu, and I want to get the GCC running on arm-linux-gnueabihf.
>> I grabbed system headers and libraries from the target and put it in the prefix path.
>>
>> In the first step I do
>>
>> ../gcc-4.9-20131208/configure --prefix=/home/ed/gnu/arm-linux-gnueabihf-linux64 --target=arm-linux-gnueabihf --enable-languages=c,c++,fortran --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=vfpv3-d16 --with-float=hard
>>
>> This GCC runs on PC and generates arm-linux-gnueabihf executables.
>>
>> Then I try this
>>
>> ../gcc-4.9-20131208/configure --prefix=/home/ed/gnu/arm-linux-gnueabihf-cross --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf --enable-languages=c,c++,fortran --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=vfpv3-d16 --with-float=hard
>>
>> But It fails because auto-build.h contains nonsense. That is probably because almost every check
>> has a fatal error #include <gmp.h> not found.
>>
>> I personally prefer to have gmp, mpfr, mpc in-tree (using contrib/download_prerequisites).
>>
>> I experimented a bit and at least this attached patch improves the situation for me.
>>
>> Maybe I never had any problems with GMP before, because the in-tree configuration of GMP does -DNO_ASM ?
>
> GMPINC really shouldn't be used to find build headers, since it is used
> to find host headers. See the top level Makefile.in. When gmp has
> been installed, using GMPINC means you pull in a whole lot of host
> headers for the build compiler. Which might work in rare cases, but
> it's a lot more likely to fail. Even with in-tree gmp, how do you get
> things like GMP_LIMB_BITS correct if your build machine is 64-bit and
> your host is 32-bit? (Perhaps there is some build magic that allows
> this to work, I'll investigate when I get back from vacation.)
>

I do not know, but until last week the only problem was a missing SSIZE_MAX
in gcc/config/host-linux.c (glimits.h does not define this, and fix-include replaced mine!)

We need the auto-build only to build something that translates .md files to .c,
so I would'nt care about GMP, but some other things, like the right prototype for
printf make a difference.

now the auto-build.h has 
#define HAVE_DECL_SBRK 0

last week that was
#define HAVE_DECL_SBRK 1

I can give you my sys-root files, and you can play with it if you like.


> Incidentally, we've been using a couple of other patches for
> build != host that I haven't posted because I wasn't sure who authored
> them. It's possible the first one might help you.
>
> diff --git a/gcc/Makefile.in b/gcc/Makefile.in
> index aad927c..7995e64 100644
> --- a/gcc/Makefile.in
> +++ b/gcc/Makefile.in
> @@ -747,7 +747,8 @@ BUILD_LINKERFLAGS = $(BUILD_CXXFLAGS)
>
> # Native linker and preprocessor flags. For x-fragment overrides.
> BUILD_LDFLAGS=@BUILD_LDFLAGS@
> -BUILD_CPPFLAGS=$(ALL_CPPFLAGS)
> +BUILD_CPPFLAGS= -I. -I$(@D) -I$(srcdir) -I$(srcdir)/$(@D) \
> + -I$(srcdir)/../include $(CPPINC)
>

I did not have this one.
What is it good for?

> # Actual name to use when installing a native compiler.
> GCC_INSTALL_NAME := $(shell echo gcc|sed '$(program_transform_name)')
> diff --git a/gcc/ada/gcc-interface/Make-lang.in b/gcc/ada/gcc-interface/Make-lang.in
> index 57f9009..e1d3ed6 100644
> --- a/gcc/ada/gcc-interface/Make-lang.in
> +++ b/gcc/ada/gcc-interface/Make-lang.in
> @@ -625,7 +625,7 @@ ada.tags: force
> ada/doctools/xgnatugn$(build_exeext): ada/xgnatugn.adb
> -$(MKDIR) ada/doctools
> $(CP) $^ ada/doctools
> - cd ada/doctools && $(GNATMAKE) -q xgnatugn
> + cd ada/doctools && gnatmake -q xgnatugn
>

Yes, I also have that. It's a show-stopper for Ada.

> # Note that doc/gnat_ugn.texi and doc/projects.texi do not depend on
> # xgnatugn being built so we can distribute a pregenerated doc/gnat_ugn.info
> diff --git a/gnattools/Makefile.in b/gnattools/Makefile.in
> index 794d374..6b0d5e8 100644
> --- a/gnattools/Makefile.in
> +++ b/gnattools/Makefile.in
> @@ -23,6 +23,7 @@ SHELL = @SHELL@
> srcdir = @srcdir@
> libdir = @libdir@
> build = @build@
> +host = @host@
> target = @target@
> prefix = @prefix@
> INSTALL = @INSTALL@
> @@ -31,6 +32,7 @@ INSTALL_PROGRAM = @INSTALL_PROGRAM@
>
> # Nonstandard autoconf-set variables.
> LN_S=@LN_S@
> +host_alias=@host_alias@
> target_noncanonical=@target_noncanonical@
>
> # Variables for the user (or the top level) to override.
> @@ -183,7 +185,11 @@ regnattools: $(GCC_DIR)/stamp-gnatlib-rts
> # put the host RTS dir first in the PATH to hide the default runtime
> # files that are among the sources
> # FIXME: This should be done in configure.
> +ifeq ($(host), $(build))
> RTS_DIR:=$(strip $(subst \,/,$(shell gnatls -v | grep adalib )))
> +else
> +RTS_DIR:=$(strip $(subst \,/,$(shell $(host_alias)-gnatls -v | grep adalib )))
> +endif
> gnattools-cross: $(GCC_DIR)/stamp-tools
> # gnattools1-re
> $(MAKE) -C $(GCC_DIR)/ada/tools -f ../Makefile \
>
> --
> Alan Modra
> Australia Development Lab, IBM