On 05/01/2013 07:40 PM, Mike Stump wrote:
$ bash -c "trap 'echo remove lock' 0; true"; echo $?
Thanks for the suggestion. Here's a revised patch:
commit 79b52becc6a8649933f7442d46e8054f8b6abd4b
Author: Jason Merrill <ja...@redhat.com>
Date: Thu Apr 25 17:54:17 2013 -0400
* Makefile.in (link-mutex, remove-link-mutex): New targets.
(native, mostlyclean): Remove link mutex.
* configure.ac: Handle --enable-link-mutex.
* */Make-lang.in: Use link mutex.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 903125e..f8968c5 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1737,8 +1737,8 @@ start.encap: native xgcc$(exeext) cpp$(exeext) specs \
rest.encap: lang.rest.encap
# This is what is made with the host's compiler
# whether making a cross compiler or not.
-native: config.status auto-host.h build-@POSUB@ $(LANGUAGES) \
- $(EXTRA_PROGRAMS) $(COLLECT2) lto-wrapper$(exeext) \
+native: remove-link-mutex config.status auto-host.h build-@POSUB@ \
+ $(LANGUAGES) $(EXTRA_PROGRAMS) $(COLLECT2) lto-wrapper$(exeext) \
gcc-ar$(exeext) gcc-nm$(exeext) gcc-ranlib$(exeext)
ifeq ($(enable_plugin),yes)
@@ -4529,6 +4529,8 @@ mostlyclean: lang.mostlyclean
-rm -f gtype.state
# Delete genchecksum outputs
-rm -f *-checksum.c
+# Delete front-end linking mutex directory
+ -rm -rf link-mutex
# Delete all files made by compilation
# that don't exist in the distribution.
@@ -5335,3 +5337,20 @@ po/gcc.pot: force
$(MAKE) srcextra
AWK=$(AWK) $(SHELL) $(srcdir)/po/exgettext \
$(XGETTEXT) gcc $(srcdir)
+
+# Like LINKER, but remove the link mutex. Used for linking front ends.
+ifeq (@DO_LINK_MUTEX@,true)
+LLINKER = trap '$(MAKE) remove-link-mutex' 0; $(LINKER)
+else
+LLINKER = $(LINKER)
+endif
+
+.PHONY: link-mutex
+link-mutex:
+ifeq (@DO_LINK_MUTEX@,true)
+ while ! mkdir link-mutex 2>/dev/null; do sleep 1; done
+endif
+
+.PHONY: remove-link-mutex
+remove-link-mutex:
+ -rm -rf link-mutex
diff --git a/gcc/ada/gcc-interface/Make-lang.in b/gcc/ada/gcc-interface/Make-lang.in
index ef12b4b..c7eda7e 100644
--- a/gcc/ada/gcc-interface/Make-lang.in
+++ b/gcc/ada/gcc-interface/Make-lang.in
@@ -185,6 +185,7 @@ endif
GCC_LINKERFLAGS = $(filter-out -Werror, $(ALL_LINKERFLAGS))
GCC_LINK=$(LINKER) $(GCC_LINKERFLAGS) $(LDFLAGS)
+GCC_LLINK=$(LLINKER) $(GCC_LINKERFLAGS) $(LDFLAGS)
# Lists of files for various purposes.
@@ -562,7 +563,9 @@ TARGET_ADA_SRCS =
# Since the RTL should be built with the latest compiler, remove the
# stamp target in the parent directory whenever gnat1 is rebuilt
gnat1$(exeext): $(TARGET_ADA_SRCS) $(GNAT1_OBJS) $(ADA_BACKEND) libcommon-target.a $(LIBDEPS)
- +$(GCC_LINK) -o $@ $(GNAT1_OBJS) $(ADA_BACKEND) libcommon-target.a $(LIBS) $(SYSLIBS) $(BACKENDLIBS) $(CFLAGS)
+ $(MAKE) link-mutex
+ +$(GCC_LLINK) -o $@ $(GNAT1_OBJS) $(ADA_BACKEND) \
+ libcommon-target.a $(LIBS) $(SYSLIBS) $(BACKENDLIBS) $(CFLAGS)
$(RM) stamp-gnatlib2-rts stamp-tools
gnatbind$(exeext): ada/b_gnatb.o $(CONFIG_H) $(GNATBIND_OBJS) ggc-none.o libcommon-target.a $(LIBDEPS)
diff --git a/gcc/c/Make-lang.in b/gcc/c/Make-lang.in
index 8310e0a..1b6189a 100644
--- a/gcc/c/Make-lang.in
+++ b/gcc/c/Make-lang.in
@@ -75,7 +75,8 @@ cc1-checksum.c : build/genchecksum$(build_exeext) checksum-options \
cc1-checksum.o : cc1-checksum.c $(CONFIG_H) $(SYSTEM_H)
cc1$(exeext): $(C_OBJS) cc1-checksum.o $(BACKEND) $(LIBDEPS)
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ $(C_OBJS) \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ $(C_OBJS) \
cc1-checksum.o $(BACKEND) $(LIBS) $(BACKENDLIBS)
#
# Build hooks:
diff --git a/gcc/configure b/gcc/configure
index 5161ae4..bd81007 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -670,6 +670,7 @@ subdirs
dollar
gcc_tooldir
enable_lto
+DO_LINK_MUTEX
MAINT
zlibinc
zlibdir
@@ -916,6 +917,7 @@ with_long_double_128
with_gc
with_system_zlib
enable_maintainer_mode
+enable_link_mutex
enable_version_specific_runtime_libs
enable_plugin
enable_libquadmath_support
@@ -1627,6 +1629,8 @@ Optional Features:
--enable-maintainer-mode
enable make rules and dependencies not useful (and
sometimes confusing) to the casual installer
+ --enable-link-mutex avoid linking multiple front-ends at once to avoid
+ thrashing on the build machine
--enable-version-specific-runtime-libs
specify that runtime libraries should be installed
in a compiler-specific directory
@@ -17830,7 +17834,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 17833 "configure"
+#line 17837 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -17936,7 +17940,7 @@ else
lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
lt_status=$lt_dlunknown
cat > conftest.$ac_ext <<_LT_EOF
-#line 17939 "configure"
+#line 17943 "configure"
#include "confdefs.h"
#if HAVE_DLFCN_H
@@ -27044,6 +27048,26 @@ else
MAINT='#'
fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether to avoid linking multiple front-ends at once" >&5
+$as_echo_n "checking whether to avoid linking multiple front-ends at once... " >&6; }
+ # Check whether --enable-link-mutex was given.
+if test "${enable_link_mutex+set}" = set; then :
+ enableval=$enable_link_mutex; do_link_mutex=$enableval
+else
+ do_link_mutex=no
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $do_link_mutex" >&5
+$as_echo "$do_link_mutex" >&6; }
+
+if test "$do_link_mutex" = "yes"; then
+ DO_LINK_MUTEX=true
+else
+ DO_LINK_MUTEX=false
+fi
+
+
# --------------
# Language hooks
# --------------
diff --git a/gcc/configure.ac b/gcc/configure.ac
index b042f00..9ab03ec 100644
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -4941,6 +4941,24 @@ else
fi
AC_SUBST(MAINT)dnl
+dnl Whether to prevent multiple front-ends from linking at the same time
+
+AC_MSG_CHECKING([whether to avoid linking multiple front-ends at once])
+ AC_ARG_ENABLE(link-mutex,
+[AS_HELP_STRING([--enable-link-mutex],
+ [avoid linking multiple front-ends at once to avoid thrashing
+ on the build machine])],
+ do_link_mutex=$enableval,
+ do_link_mutex=no)
+AC_MSG_RESULT($do_link_mutex)
+
+if test "$do_link_mutex" = "yes"; then
+ DO_LINK_MUTEX=true
+else
+ DO_LINK_MUTEX=false
+fi
+AC_SUBST(DO_LINK_MUTEX)
+
# --------------
# Language hooks
# --------------
diff --git a/gcc/cp/Make-lang.in b/gcc/cp/Make-lang.in
index cda4897..f8b3583 100644
--- a/gcc/cp/Make-lang.in
+++ b/gcc/cp/Make-lang.in
@@ -100,7 +100,8 @@ cc1plus-checksum.c : build/genchecksum$(build_exeext) checksum-options \
cc1plus-checksum.o : cc1plus-checksum.c $(CONFIG_H) $(SYSTEM_H)
cc1plus$(exeext): $(CXX_OBJS) cc1plus-checksum.o $(BACKEND) $(LIBDEPS)
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(CXX_OBJS) cc1plus-checksum.o $(BACKEND) $(LIBS) $(BACKENDLIBS)
ifeq ($(ENABLE_MAINTAINER_RULES), true)
diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi
index 1265129..7d7a5c7 100644
--- a/gcc/doc/install.texi
+++ b/gcc/doc/install.texi
@@ -1293,6 +1293,13 @@ opposite effect. If neither option is specified, the configure script
will try to guess whether the @code{.init_array} and
@code{.fini_array} sections are supported and, if they are, use them.
+@item --enable-link-mutex
+When building GCC, use a mutex to avoid linking the compilers for
+multiple languages at the same time, to avoid thrashing on build
+systems with limited free memory. This functionality requires that
+the default shell be bash, as it uses the 'trap' built-in command.
+The default is not to use such a mutex.
+
@item --enable-maintainer-mode
The build rules that regenerate the Autoconf and Automake output files as
well as the GCC master message catalog @file{gcc.pot} are normally
diff --git a/gcc/fortran/Make-lang.in b/gcc/fortran/Make-lang.in
index c3f826c..4e414e2 100644
--- a/gcc/fortran/Make-lang.in
+++ b/gcc/fortran/Make-lang.in
@@ -98,7 +98,8 @@ gfortran-cross$(exeext): gfortran$(exeext)
# The compiler itself is called f951.
f951$(exeext): $(F95_OBJS) \
$(BACKEND) $(LIBDEPS) attribs.o
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(F95_OBJS) $(BACKEND) $(ZLIB) $(LIBS) attribs.o \
$(BACKENDLIBS)
diff --git a/gcc/go/Make-lang.in b/gcc/go/Make-lang.in
index dd98080..93ed920 100644
--- a/gcc/go/Make-lang.in
+++ b/gcc/go/Make-lang.in
@@ -76,7 +76,8 @@ GO_OBJS = \
go/unsafe.o
go1$(exeext): $(GO_OBJS) attribs.o $(BACKEND) $(LIBDEPS)
- +$(CXX) $(ALL_CXXFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(GO_OBJS) attribs.o $(BACKEND) $(LIBS) $(BACKENDLIBS)
# Documentation.
diff --git a/gcc/java/Make-lang.in b/gcc/java/Make-lang.in
index 7ed3220..4d2ef8a 100644
--- a/gcc/java/Make-lang.in
+++ b/gcc/java/Make-lang.in
@@ -99,7 +99,8 @@ jvspec.o-warn = -Wno-error
jc1$(exeext): $(JAVA_OBJS) $(BACKEND) $(LIBDEPS) attribs.o
rm -f $@
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(JAVA_OBJS) $(BACKEND) $(ZLIB) $(LIBICONV) $(LIBS) attribs.o $(BACKENDLIBS)
jcf-dump$(exeext): $(JCFDUMP_OBJS) $(LIBDEPS)
diff --git a/gcc/lto/Make-lang.in b/gcc/lto/Make-lang.in
index a0bdc26..e0db780 100644
--- a/gcc/lto/Make-lang.in
+++ b/gcc/lto/Make-lang.in
@@ -71,7 +71,8 @@ lto.stagefeedback:
lto-warn = $(STRICT_WARN)
$(LTO_EXE): $(LTO_OBJS) $(BACKEND) $(LIBDEPS)
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(LTO_OBJS) $(BACKEND) $(BACKENDLIBS) $(LIBS)
# Dependencies
diff --git a/gcc/objc/Make-lang.in b/gcc/objc/Make-lang.in
index 9e005c1..5faf54c 100644
--- a/gcc/objc/Make-lang.in
+++ b/gcc/objc/Make-lang.in
@@ -68,7 +68,8 @@ cc1obj-checksum.c : build/genchecksum$(build_exeext) checksum-options \
cc1obj-checksum.o : cc1obj-checksum.c $(CONFIG_H) $(SYSTEM_H)
cc1obj$(exeext): $(OBJC_OBJS) $(C_AND_OBJC_OBJS) cc1obj-checksum.o $(BACKEND) $(LIBDEPS)
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(OBJC_OBJS) $(C_AND_OBJC_OBJS) cc1obj-checksum.o \
$(BACKEND) $(LIBS) $(BACKENDLIBS)
diff --git a/gcc/objcp/Make-lang.in b/gcc/objcp/Make-lang.in
index 731ca9e..665e91e 100644
--- a/gcc/objcp/Make-lang.in
+++ b/gcc/objcp/Make-lang.in
@@ -72,7 +72,8 @@ cc1objplus-checksum.c : build/genchecksum$(build_exeext) checksum-options \
cc1objplus-checksum.o : cc1objplus-checksum.c $(CONFIG_H) $(SYSTEM_H)
cc1objplus$(exeext): $(OBJCXX_OBJS) cc1objplus-checksum.o $(BACKEND) $(LIBDEPS)
- +$(LINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
+ $(MAKE) link-mutex
+ +$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ \
$(OBJCXX_OBJS) cc1objplus-checksum.o $(BACKEND) $(LIBS) $(BACKENDLIBS)
# Objective C++ language specific files.
