Initial commit

poky/meta/recipes-devtools/gcc/libgcc-initial.inc

@@ -0,0 +1,58 @@
+#
+# Notes on the way the OE cross toolchain now works
+#
+# We need a libgcc to build glibc. Tranditionally we therefore built
+# a non-threaded and non-shared compiler (gcc-cross-initial), then use
+# that to build libgcc-initial which is used to build glibc which we can
+# then build gcc-cross and libgcc against.
+#
+# We were able to drop the glibc dependency from gcc-cross, with two tweaks:
+
+# a) specify the minimum glibc version to support in a configure option
+# b) create a dummy limits.h file so that later when glibc creates one,
+#    the headers structure has support for it. We can do this with a simple
+#    empty file
+#
+# Once gcc-cross is libc independent, we can use it to build both
+# libgcc-initial and then later libgcc.
+#
+# libgcc-initial is tricky as we need to imitate the non-threaded and
+# non-shared case. We can do that by hacking the threading mode back to
+# "single" even if gcc reports "posix" and disable libc presence for the
+# libgcc-intial build. We have to create the dummy limits.h to avoid
+# compiler errors from a missing header.
+#
+# glibc will fail to link with libgcc-initial due to a missing "exception
+# handler" capable libgcc (libgcc_eh.a). Since we know glibc doesn't need
+# any exception handler, we can safely symlink to libgcc.a.
+#
+
+require libgcc-common.inc
+
+DEPENDS = "virtual/${TARGET_PREFIX}gcc"
+
+LICENSE = "GPL-3.0-with-GCC-exception"
+
+PACKAGES = ""
+
+EXTRA_OECONF += "--disable-shared"
+
+inherit nopackages
+
+# We really only want this built by things that need it, not any recrdeptask
+deltask do_build
+
+do_configure:prepend () {
+	install -d ${STAGING_INCDIR}
+	touch ${STAGING_INCDIR}/limits.h
+	sed -i -e 's#INHIBIT_LIBC_CFLAGS =.*#INHIBIT_LIBC_CFLAGS = -Dinhibit_libc#' ${B}/gcc/libgcc.mvars
+	sed -i -e 's#inhibit_libc = false#inhibit_libc = true#' ${B}/gcc/Makefile
+}
+
+do_configure:append () {
+	sed -i -e 's#thread_header = .*#thread_header = gthr-single.h#' ${B}/${BPN}/Makefile
+}
+
+do_install:append () {
+	ln -s libgcc.a ${D}${libdir}/${TARGET_SYS}/${BINV}/libgcc_eh.a
+}