Hi! Ping. To sum it up, with these patches applied, there are no changes for a "regular" build (not using the new configure options). On the other hand, configuring GCC as described, it is possible use the 32-bit x86 linker for/with a x86_64 build, and get the very same GCC test results as when using a x86_64 linker.
On Mon, 14 Oct 2013 12:28:11 +0200, I wrote: > On Sat, 12 Oct 2013 12:20:19 +0200, I wrote: > > This is a bit of a weird scenario -- but it is supposed to work fine in > > my opinion (but doesn't). > > > > I have a GNU toolchain as 32-bit x86 GNU/Linux executables, configured to > > to generate code for 32-bit x86 by default, and using -m64 for x86_64. > > > > This toolchain I'm using on a x86_64 system (which can execute 32-bit > > executables) to build a *native* GCC, that is I'm using the 32-bit > > toolchain to build a x86_64 GCC (configuring with CC='gcc -m64' CXX='g++ > > -m64'). I intend to continue using the 32-bit toolchain's linker, which > > also is a 32-bit executable (GNU ld). That one also defaults to x86 > > code, but can handle the x86_64 case fine if passed -m elf_x86_64, which > > GCC does. > > > > That the linker is a 32-bit executable is an implementation detail that > > is not important generally: it's a separate process living in its own > > address space. However it becomes relevant in the case of linker > > plugins: the native x86_64 GCC that I'm building also builds a x86_64 > > lto-plugin, which the 32-bit ld cannot load: > > > > $ gcc/xgcc -B[...] [...]/gcc.c-torture/execute/ieee/20000320-1.c [...] > > -flto [...] > > [...]/ld: [...]/gcc/liblto_plugin.so: error loading plugin: > > [...]/gcc/liblto_plugin.so: wrong ELF class: ELFCLASS64 > > collect2: error: ld returned 1 exit status > > > > So, aside from building a 64-bit ld (which is the "lame" alternative), I > > now need to teach GCC's build system that the lto-plugin may need special > > configuration: CC='gcc -m32' -- and [...] its own build of libiberty, > > too [...] > > > Instead of auto-detecting the linker's > > architecture (and then, what to do with that information?), I intend to > > make this a manual process (so, some new top-level configure > > argument(s)). Adding yet another set of {...,CC,...}_FOR_[something] is > > probably overkill -- I'll try to find something simpler. > > > > Any comments on this scenario? > > Here are the patches. Unless the new option is exercised, there are no > effects on a native x86_64 GNU/Linux bootstrap build (the build trees' > *.o files are identical, as are the test results). OK to commit? > Allow overriding the libiberty used for building the LTO plugin. > > lto-plugin/ > * configure.ac (--with-libiberty): New configure option. > * configure: Regenerate. > * Makefile.am (libiberty, libiberty_pic): New variables. > (liblto_plugin_la_LIBADD, liblto_plugin_la_LDFLAGS) > (liblto_plugin_la_DEPENDENCIES): Use them. > * Makefile.in: Regenerate. > --- > lto-plugin/Makefile.am | 20 +++++++++++--------- > lto-plugin/Makefile.in | 22 ++++++++++++---------- > lto-plugin/configure | 17 +++++++++++++++-- > lto-plugin/configure.ac | 5 +++++ > 4 files changed, 43 insertions(+), 21 deletions(-) > > diff --git lto-plugin/Makefile.am lto-plugin/Makefile.am > index b24015e..8b7bb54 100644 > --- lto-plugin/Makefile.am > +++ lto-plugin/Makefile.am > @@ -15,17 +15,19 @@ libexecsub_LTLIBRARIES = liblto_plugin.la > gcc_build_dir = ../$(host_subdir)/gcc > in_gcc_libs = $(foreach lib, $(libexecsub_LTLIBRARIES), > $(gcc_build_dir)/$(lib)) > > -# Can be removed when libiberty becomes a normal convenience library > -Wc=-Wc, > - > liblto_plugin_la_SOURCES = lto-plugin.c > +# Note that we intentionally override the bindir supplied by > ACX_LT_HOST_FLAGS. > +liblto_plugin_la_LDFLAGS = $(lt_host_flags) -module -bindir $(libexecsubdir) > +# Can be simplified when libiberty becomes a normal convenience library. > +libiberty=$(with_libiberty)/libiberty.a > +libiberty_pic=$(with_libiberty)/pic/libiberty.a > +Wc=-Wc, > liblto_plugin_la_LIBADD = \ > - $(if $(wildcard > ../libiberty/pic/libiberty.a),$(Wc)../libiberty/pic/libiberty.a,) > -# Note that we intentionally override the bindir supplied by > ACX_LT_HOST_FLAGS > -liblto_plugin_la_LDFLAGS = $(lt_host_flags) -module -bindir $(libexecsubdir) > \ > - $(if $(wildcard > ../libiberty/pic/libiberty.a),,-Wc,../libiberty/libiberty.a) > -liblto_plugin_la_DEPENDENCIES = $(if $(wildcard \ > - ../libiberty/pic/libiberty.a),../libiberty/pic/libiberty.a,) > + $(if $(wildcard $(libiberty_pic)),$(Wc)$(libiberty_pic),) > +liblto_plugin_la_LDFLAGS += \ > + $(if $(wildcard $(libiberty_pic)),,-Wc,$(libiberty)) > +liblto_plugin_la_DEPENDENCIES = \ > + $(if $(wildcard $(libiberty_pic)),$(libiberty_pic),) > > all-local: $(in_gcc_libs) > > diff --git lto-plugin/configure.ac lto-plugin/configure.ac > index 9a418d2..b73fabb 100644 > --- lto-plugin/configure.ac > +++ lto-plugin/configure.ac > @@ -4,6 +4,11 @@ AC_CANONICAL_SYSTEM > GCC_TOPLEV_SUBDIRS > AM_INIT_AUTOMAKE([foreign no-dist]) > AM_MAINTAINER_MODE > +AC_ARG_WITH(libiberty, > + [AS_HELP_STRING([--with-libiberty=PATH], > + [specify the directory where to find libiberty [../libiberty]])], > + [], with_libiberty=../libiberty) > +AC_SUBST(with_libiberty) > AC_PROG_CC > AC_SYS_LARGEFILE > ACX_PROG_CC_WARNING_OPTS([-Wall], [ac_lto_plugin_warn_cflags]) > Allow for overriding a module's srcdir. > > * Makefile.tpl (configure-[+prefix+][+module+]) > (configure-stage[+id+]-[+prefix+][+module+]): Allow for > overriding a module's srcdir. > * Makefile.in: Regenerate. > > --- > Makefile.in | 2141 > ++++++++++++++++++++++++++++++---------------------------- > Makefile.tpl | 21 +- > 2 files changed, 1132 insertions(+), 1030 deletions(-) > > diff --git Makefile.tpl Makefile.tpl > index 2695a2b..36d480e 100644 > --- Makefile.tpl > +++ Makefile.tpl > @@ -1000,12 +1000,14 @@ configure-[+prefix+][+module+]: [+ IF bootstrap +][+ > ELSE +] > *) topdir=`echo [+subdir+]/[+module+]/ | \ > sed -e 's,\./,,g' -e 's,[^/]*/,../,g' `$(srcdir) ;; \ > esac; \ > - srcdiroption="--srcdir=$${topdir}/[+module+]"; \ > - libsrcdir="$$s/[+module+]"; \ > + module_srcdir=[+ IF module_srcdir +][+module_srcdir+][+ > + ELSE module_srcdir +][+module+][+ ENDIF module_srcdir +]; \ > [+ IF no-config-site +]rm -f no-such-file || : ; \ > - CONFIG_SITE=no-such-file [+ ENDIF +]$(SHELL) $${libsrcdir}/configure \ > + CONFIG_SITE=no-such-file [+ ENDIF +]$(SHELL) \ > + $$s/$$module_srcdir/configure \ > + --srcdir=$${topdir}/$$module_srcdir \ > [+args+] --build=${build_alias} --host=[+host_alias+] \ > - --target=[+target_alias+] $${srcdiroption} [+extra_configure_flags+] \ > + --target=[+target_alias+] [+extra_configure_flags+] \ > || exit 1 > @endif [+prefix+][+module+] > > @@ -1053,12 +1055,13 @@ configure-stage[+id+]-[+prefix+][+module+]: > *) topdir=`echo [+subdir+]/[+module+]/ | \ > sed -e 's,\./,,g' -e 's,[^/]*/,../,g' `$(srcdir) ;; \ > esac; \ > - srcdiroption="--srcdir=$${topdir}/[+module+]"; \ > - libsrcdir="$$s/[+module+]"; \ > - $(SHELL) $${libsrcdir}/configure \ > + module_srcdir=[+ IF module_srcdir +][+module_srcdir+][+ > + ELSE module_srcdir +][+module+][+ ENDIF module_srcdir +]; \ > + $(SHELL) $$s/$$module_srcdir/configure \ > + --srcdir=$${topdir}/$$module_srcdir \ > [+args+] --build=${build_alias} --host=[+host_alias+] \ > - --target=[+target_alias+] $${srcdiroption} [+ IF prev +]\ > - --with-build-libsubdir=$(HOST_SUBDIR) [+ ENDIF prev +]\ > + --target=[+target_alias+] \ > + [+ IF prev +] --with-build-libsubdir=$(HOST_SUBDIR) [+ ENDIF prev +] \ > $(STAGE[+id+]_CONFIGURE_FLAGS)[+ IF extra_configure_flags +] \ > [+extra_configure_flags+][+ ENDIF extra_configure_flags +] > @endif [+prefix+][+module+]-bootstrap > Non-host system configuration for linker plugins. > > * configure.ac (--enable-linker-plugin-flags) > (--enable-linker-plugin-configure-flags): New flags. > (configdirs): Conditionally add libiberty-linker-plugin. > * configure: Regenerate. > * Makefile.def (host_modules): Add libiberty-linker-plugin. > (host_modules) <lto-plugin>: Pay attention to > @extra_linker_plugin_flags@ and > @extra_linker_plugin_configure_flags@. > (all-lto-plugin): Also depend on all-libiberty-linker-plugin. > * Makefile.in: Regenerate. > gcc/ > * doc/install.texi (--enable-linker-plugin-flags) > (--enable-linker-plugin-configure-flags): Document new flags. > --- > Makefile.def | 14 +- > Makefile.in | 1051 > ++++++++++++++++++++++++++++++++++++++++++++++++-- > configure | 42 ++ > configure.ac | 28 ++ > gcc/doc/install.texi | 19 + > 5 files changed, 1117 insertions(+), 37 deletions(-) > > diff --git Makefile.def Makefile.def > index 3ba1a5b..ea48792 100644 > --- Makefile.def > +++ Makefile.def > @@ -85,6 +85,14 @@ host_modules= { module= libdecnumber; bootstrap=true; }; > host_modules= { module= libgui; }; > host_modules= { module= libiberty; bootstrap=true; > > extra_configure_flags='@extra_host_libiberty_configure_flags@';}; > +// Linker plugins may need their own build of libiberty; see > +// gcc/doc/install.texi. We take care that this build of libiberty doesn't > get > +// installed. It's a helper library for linker plugins, so we pay attention > to > +// @extra_linker_plugin_flags@ and @extra_linker_plugin_configure_flags@. > +host_modules= { module= libiberty-linker-plugin; bootstrap=true; > + module_srcdir=libiberty; > + extra_configure_flags='@extra_host_libiberty_configure_flags@ > --disable-install-libiberty @extra_linker_plugin_flags@ > @extra_linker_plugin_configure_flags@'; > + extra_make_flags='@extra_linker_plugin_flags@'; }; > // We abuse missing to avoid installing anything for libiconv. > host_modules= { module= libiconv; > extra_configure_flags='--disable-shared'; > @@ -111,7 +119,8 @@ host_modules= { module= libtermcap; no_check=true; > host_modules= { module= utils; no_check=true; }; > host_modules= { module= gnattools; }; > host_modules= { module= lto-plugin; bootstrap=true; > - extra_configure_flags=--enable-shared; }; > + extra_configure_flags='--enable-shared > @extra_linker_plugin_flags@ @extra_linker_plugin_configure_flags@'; > + extra_make_flags='@extra_linker_plugin_flags@'; }; > > target_modules = { module= libstdc++-v3; > bootstrap=true; > @@ -336,7 +345,10 @@ dependencies = { module=all-fixincludes; > on=all-libiberty; }; > > dependencies = { module=all-gnattools; on=all-target-libada; }; > > +// Depending on the specific configuration, the LTO plugin will either use > the > +// generic libiberty build or the specific build for linker plugins. > dependencies = { module=all-lto-plugin; on=all-libiberty; }; > +dependencies = { module=all-lto-plugin; on=all-libiberty-linker-plugin; }; > > dependencies = { module=all-utils; on=all-libiberty; }; > > diff --git configure.ac configure.ac > index b5caebb..128c60b 100644 > --- configure.ac > +++ configure.ac > @@ -1731,6 +1731,19 @@ ACX_ELF_TARGET_IFELSE([# ELF platforms build the > lto-plugin always. > esac > ]) > > +AC_ARG_ENABLE(linker-plugin-flags, > + [AS_HELP_STRING([[--enable-linker-plugin-flags=FLAGS]], > + [additional flags for configuring and building linker plugins > @<:@none@:>@])], > + extra_linker_plugin_flags=$enableval, > + extra_linker_plugin_flags=) > +AC_SUBST(extra_linker_plugin_flags) > +AC_ARG_ENABLE(linker-plugin-configure-flags, > + [AS_HELP_STRING([[--enable-linker-plugin-configure-flags=FLAGS]], > + [additional flags for configuring linker plugins @<:@none@:>@])], > + extra_linker_plugin_configure_flags=$enableval, > + extra_linker_plugin_configure_flags=) > +AC_SUBST(extra_linker_plugin_configure_flags) > + > > # By default, C and C++ are the only stage 1 languages. > stage1_languages=,c, > @@ -2133,6 +2146,21 @@ for i in ${target_configdirs_all} ; do > fi > done > > +# libiberty-linker-plugin is special: it doesn't have its own source > directory, > +# so we have to add it after the preceding checks. > +if test x"$extra_linker_plugin_flags$extra_linker_plugin_configure_flags" != > x > +then > + case " $configdirs " in > + *" libiberty "*) > + # If we can build libiberty, we can also build libiberty-linker-plugin. > + configdirs="$configdirs libiberty-linker-plugin" > + > extra_linker_plugin_configure_flags="$extra_linker_plugin_configure_flags \ > + --with-libiberty=../libiberty-linker-plugin";; > + *) > + AC_MSG_ERROR([libiberty missing]);; > + esac > +fi > + > # Produce a warning message for the subdirs we can't configure. > # This isn't especially interesting in the Cygnus tree, but in the individual > # FSF releases, it's important to let people know when their machine isn't > diff --git gcc/doc/install.texi gcc/doc/install.texi > index 7be8e5a..74cf660 100644 > --- gcc/doc/install.texi > +++ gcc/doc/install.texi > @@ -1746,6 +1746,25 @@ GLIBC 2.11 or above, otherwise disabled. > Enable support for link-time optimization (LTO). This is enabled by > default, and may be disabled using @option{--disable-lto}. > > +@item --enable-linker-plugin-flags=FLAGS > +@itemx --enable-linker-plugin-configure-flags=FLAGS > +By default, linker plugins (such as the LTO plugin) are built for the > +host system architecture. For the case that the linker has a > +different (but run-time compatible) architecture, these flags can be > +specified to build plugins that are compatible to the linker. For > +example, if you are building GCC for a 64-bit x86_64 > +(@samp{x86_64-unknown-linux-gnu}) host system, but have a 32-bit x86 > +GNU/Linux (@samp{i686-pc-linux-gnu}) linker executable (which is > +executable on the former system), you can configure GCC as follows for > +getting compatible linker plugins: > + > +@smallexample > +% @var{srcdir}/configure \ > + --host=x86_64-unknown-linux-gnu \ > + --enable-linker-plugin-flags='CC=gcc\ -m32' \ > + --enable-linker-plugin-configure-flags=--host=i686-pc-linux-gnu > +@end smallexample > + > @item --with-plugin-ld=@var{pathname} > Enable an alternate linker to be used at link-time optimization (LTO) > link time when @option{-fuse-linker-plugin} is enabled. > GNU ld can use linker plugins, too. > > gcc/ > * doc/sourcebuild.texi (Top Level) <lto-plugin>: GNU ld can use > linker plugins, too. > > --- > gcc/doc/sourcebuild.texi | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git gcc/doc/sourcebuild.texi gcc/doc/sourcebuild.texi > index 90bd0bd..23ff04a 100644 > --- gcc/doc/sourcebuild.texi > +++ gcc/doc/sourcebuild.texi > @@ -120,7 +120,7 @@ The Stack protector runtime library. > The C++ runtime library. > > @item lto-plugin > -Plugin used by @command{gold} if link-time optimizations are enabled. > +Plugin used by the linker if link-time optimizations are enabled. > > @item maintainer-scripts > Scripts used by the @code{gccadmin} account on @code{gcc.gnu.org}. > Fix typo. > > * Makefile.tpl: Fix typo. > * Makefile.in: Regenerate. > > --- > Makefile.in | 2 +- > Makefile.tpl | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git Makefile.in Makefile.in > index a13771d..67d8cfb 100644 > --- Makefile.in > +++ Makefile.in > @@ -166,7 +166,7 @@ BUILD_EXPORTS = \ > WINDMC="$(WINDMC_FOR_BUILD)"; export WINDMC; > > # These variables must be set on the make command line for directories > -# built for the build system to override those in BASE_FLAGS_TO_PASSS. > +# built for the build system to override those in BASE_FLAGS_TO_PASS. > EXTRA_BUILD_FLAGS = \ > CFLAGS="$(CFLAGS_FOR_BUILD)" \ > LDFLAGS="$(LDFLAGS_FOR_BUILD)" > diff --git Makefile.tpl Makefile.tpl > index 3233a78..2695a2b 100644 > --- Makefile.tpl > +++ Makefile.tpl > @@ -169,7 +169,7 @@ BUILD_EXPORTS = \ > WINDMC="$(WINDMC_FOR_BUILD)"; export WINDMC; > > # These variables must be set on the make command line for directories > -# built for the build system to override those in BASE_FLAGS_TO_PASSS. > +# built for the build system to override those in BASE_FLAGS_TO_PASS. > EXTRA_BUILD_FLAGS = \ > CFLAGS="$(CFLAGS_FOR_BUILD)" \ > LDFLAGS="$(LDFLAGS_FOR_BUILD)" Grüße, Thomas
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