Hi! 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 possibly its own build of libiberty, > too, which it may depend on (but doesn't in my case, so I might cut this > short, and just error out).
The latter was a Saturday morning thinko: only because linking a shared
library succeeds, that doesn't mean all the symbols it depends on are
present. ;-) So I do need a special libiberty build (or get rid of the
libiberty dependency in lto-plugin, of course, which I have not
assessed).
> 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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