| Message ID | 20140821124832.22445.27923.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index bf3e6778cd71..5bd80ef22866 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -330,7 +330,7 @@ quiet_cmd_link_o_target = LD $@ cmd_link_o_target = $(if $(strip $(obj-y)),\ $(LD) $(ld_flags) -r -o $@ $(filter $(obj-y), $^) \ $(cmd_secanalysis),\ - rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@) + $(CC) $(c_flags) -x c -c - -o $@ </dev/null) $(builtin-target): $(obj-y) FORCE $(call if_changed,link_o_target)
The built-in.o files are constructed in one of two ways: (1) If there are contributory .o files, an incremental link (ld -r) is performed to generate built-in.o. (2) If there are _no_ contributory .o files, an empty archive file (ar) is generated as built-in.o. Unfortunately, with (2), if this is then incrementally linked into another built-in.o file, the e_flags field in the ELF header may not have been set. For instance, compare: >sh64-linux-gnu-ar rcsD a.o >sh64-linux-gnu-ld -r -EL -mshlelf64 -belf64-sh64l -o b.o a.o >sh64-linux-gnu-readelf -h b.o | grep Flags Flags: 0x0 to: >sh64-linux-gnu-gcc -x c -c - -o zero.o </dev/null >sh64-linux-gnu-readelf -h zero.o | grep Flags Flags: 0xa, sh5 Attempting to further incrementally link b.o generated above gets an error because e_flags is not set. >sh64-linux-gnu-ld -r -EL -mshlelf64 -belf64-sh64l -o c.o b.o sh64-linux-gnu-ld: unknown architecture of input file `b.o' is incompatible with sh5 output Further, but probably not relevant to the kernel, if an archive file is constructed that has some constituent object files in it, passing that to an incremental link, eg: #!/bin/sh -x CROSS=sh64-linux-gnu- LDFLAGS="-EL -mshlelf64 -belf64-sh64l" #LDARFLAGS=--whole-archive CFLAGS="-m5-64media-nofpu -ml" rm -f hello.o wibble.o foo.o bar.o echo 'int hello(int i) {return i + 42;}' | ${CROSS}gcc $CFLAGS -x c -c - -o hello.o || exit $? ${CROSS}readelf -h hello.o | grep Flags ${CROSS}ar rcsD wibble.o hello.o || exit $? ${CROSS}ld $LDFLAGS $LDARFLAGS -r -o foo.o wibble.o || exit $? ${CROSS}readelf -h foo.o | grep Flags ${CROSS}ld $LDFLAGS -r -o bar.o foo.o || exit $? ${CROSS}readelf -h bar.o | grep Flags won't propagate e_flags _unless_ --whole-archive is also passed to the linker. + CROSS=sh64-linux-gnu- + LDFLAGS='-EL -mshlelf64' + CFLAGS='-m5-64media-nofpu -ml' + rm -f hello.o wibble.o foo.o bar.o + echo 'int hello(int i) {return i + 42;}' + sh64-linux-gnu-gcc -m5-64media-nofpu -ml -x c -c - -o hello.o + sh64-linux-gnu-readelf -h hello.o + grep Flags Flags: 0xa, sh5 + sh64-linux-gnu-ar rcsD wibble.o hello.o + sh64-linux-gnu-ld -EL -mshlelf64 -r -o foo.o wibble.o + sh64-linux-gnu-readelf -h foo.o + grep Flags Flags: 0x0 + sh64-linux-gnu-ld -EL -mshlelf64 -r -o bar.o foo.o sh64-linux-gnu-ld: unknown architecture of input file `foo.o' is incompatible with sh5 output To this end, change the construction of empty built-in.o files (case (2) above) to use gcc on an empty file. There is a binutils bug logged for this: https://sourceware.org/bugzilla/show_bug.cgi?id=17288 Signed-off-by: David Howells <dhowells@redhat.com> --- 0 files changed -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html