$(top_builddir)/src/c++98/libc++98convenience.la \
$(top_builddir)/src/c++11/libc++11convenience.la
-if GLIBCXX_USE_LIBM
libstdc___la_LDFLAGS = \
- -version-info $(libtool_VERSION) ${version_arg} -lm
-else
-libstdc___la_LDFLAGS = \
- -version-info $(libtool_VERSION) ${version_arg}
-endif
+ -version-info $(libtool_VERSION) ${version_arg} -lm
libstdc___la_LINK = $(CXXLINK) $(libstdc___la_LDFLAGS)
compatibility-thread-c++0x.o: compatibility-thread-c++0x.cc
$(CXXCOMPILE) -std=gnu++11 -c $<
-# AM_CXXFLAGS needs to be in each subdirectory so that it can be
+# A note on compatibility and static libraries.
+#
+# static lib == linked against only this version, should not need compat
+# shared lib == linked against potentially all compat versions
+#
+# Thus, the shared libs have more compat symbols, which can be found
+# segregated in the sources with -D_GLIBCXX_SHARED.
+#
+# In the sub-directories of libsupc++, src/c++98, src/c++11, only
+# -prefer-pic objects are generated for the convenience libraries.
+#
+# In the main src directory, make shared and static objects just for
+# the compat libraries. Shared objects are compiled with -prefer-pic
+# -D_GLIBCXX_SHARED and in the .libs sub-directory, static objects are
+# compiled with -prefer-pic (ie, -fPIC but not -D_GLIBCXX_SHARED) and
+# the main src directory.
+#
+# Why are objects destined for libstdc++.a compiled with -fPIC? First,
+# because -fPIC is not harmful to use for objects destined for static
+# libraries. In addition, using -fPIC will allow the use of static
+# libstdc++.a in the creation of other C++ shared libraries.
+
+# AM_CXXFLAGS needs to be in each sub-directory so that it can be
# modified in a per-library or per-sub-library way. Need to manually
# set this option because CONFIG_CXXFLAGS has to be after
# OPTIMIZE_CXXFLAGS on the compile line so that -O2 can be overridden
# as the occasion calls for it.
AM_CXXFLAGS = \
+ $(glibcxx_compiler_pic_flag) \
$(XTEMPLATE_FLAGS) \
$(WARN_CXXFLAGS) $(OPTIMIZE_CXXFLAGS) $(CONFIG_CXXFLAGS)
# Libtool notes
-# 1) Need to explicitly set LTCXXCOMPILE so that AM_CXXFLAGS is
-# last. (That way, things like -O2 passed down from the toplevel can
-# be overridden by --enable-debug.)
-
-# 2) In general, libtool expects an argument such as `--tag=CXX' when
+# 1) In general, libtool expects an argument such as `--tag=CXX' when
# using the C++ compiler, because that will enable the settings
# detected when C++ support was being configured. However, when no
# such flag is given in the command line, libtool attempts to figure
# can't decide which configuration to use, and it gives up. The
# correct solution is to add `--tag CXX' to LTCXXCOMPILE and maybe
# CXXLINK, just after $(LIBTOOL), so that libtool doesn't have to
-# attempt to infer which configuration to use
+# attempt to infer which configuration to use.
+#
+# The second tag argument, `--tag disable-shared` means that libtool
+# only compiles each source once, for static objects. In actuality,
+# glibcxx_lt_pic_flag and glibcxx_compiler_shared_flag are added to
+# the libtool command that is used create the object, which is
+# suitable for shared libraries. The `--tag disable-shared` must be
+# placed after --tag CXX lest things CXX undo the affect of
+# disable-shared.
+
+# 2) Need to explicitly set LTCXXCOMPILE so that AM_CXXFLAGS is
+# last. (That way, things like -O2 passed down from the toplevel can
+# be overridden by --enable-debug.)
LTCXXCOMPILE = \
$(LIBTOOL) --tag CXX \
$(AM_LIBTOOLFLAGS) $(LIBTOOLFLAGS) \
fi; \
fi
$(EGREP) -v '^[ ]*#(#| |$$)' $@.tmp | \
- $(CC) -E -P -include ../config.h - > $@ || (rm -f $@ ; exit 1)
+ $(CC) -E -P -include $(CONFIG_HEADER) - > $@ || (rm -f $@ ; exit 1)
rm -f $@.tmp
CLEANFILES = libstdc++-symbols.ver
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