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Re: Re: [PATCH 1/8] PR ld/17878: Add bfd_maybe_object_p

On 09/02/15 04:36, H.J. Lu wrote:
On Sat, Feb 7, 2015 at 4:50 AM, H.J. Lu <> wrote:
On Sat, Feb 7, 2015 at 1:42 AM, Alan Modra <> wrote:
On Thu, Feb 05, 2015 at 05:54:40AM -0800, H.J. Lu wrote:
This patch adds bfd_maybe_object_p which is similar to

bfd_check_format (abfd, bfd_object)

The difference is bfd_maybe_object_p takes an argument to indicate if a
compiler plug-in library is applied.  When a compiler plug-in library is
active, it also returns TRUE if the file is not an archive or a coredump

Hmm, in other words, if it is unknown.  (bfd_format takes the values
bfd_unknown, bfd_object, bfd_archive, bfd_core.)


+bfd_maybe_object_p (bfd *abfd, bfd_boolean plugin_active_p)
+  /* LTO IR object file may look like a bfd_object file or a file which
+     is not bfd_core nor bfd_archive.  */
+  return (bfd_check_format (abfd, bfd_object)
+       || (plugin_active_p
+           && !bfd_check_format (abfd, bfd_core)
+           && !bfd_check_format (abfd, bfd_archive)));

I find this really strange.  If plugins are active then you're
willing to accept anything except cores and archives.  To throw out
cores and archives you'll be iterating over all compiled-in bfd
targets, asking "is this a core file", then asking "is this an
archive".  That's quite a bit of processing, and won't exclude your
average text file!

LTO IR could be stored in the average text file.  The new plug tests
use this feature.   We can add a new type, bfd_maybe_object.

I think you need to find a way of answering the question "is this a
file accepted by a plugin?" in a more robust way.  One possibility is
merging the linker handling of plugins into the bfd plugin support.

I have considered it before.  This approach has many implications.
If we do this, we need to add bfd_plugin_object and bfd_all_object.
bfd_all_object includes bfd_object and bfd_plugin_object.  We need
bfd_plugin_object so that we won't update dummy BFD info from the
LTO IR input.  Let me take another look.

Here is a draft to make linker plugin_object_p available to BFD:;a=patch;h=23903a326cd1cb205902698bb61f9deb1d1bf9a9

I will submit a proper patch tomorrow.

Hi Lu,
After this patch on arm-none-eabi and arm-none-linux-gnueabihf I see following regressions:
FAIL: load plugin 2 with source
FAIL: load plugin 3 with source
FAIL: plugin 2 with source lib
FAIL: plugin 3 with source lib
FAIL: plugin claimfile replace symbol with source
FAIL: plugin claimfile resolve symbol with source

when I run test src/binutils-gdb/ld/testsuite/ld-plugin/func.c
, I see:
/work/fsf-trunk-3/build-arm-none-eabi/install/bin/arm-none-eabi-gcc -B/work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/ld/ -I/work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin -O2 -specs=rdimon.specs -Wa,-mno-warn-deprecated -mthumb -O2 -c /work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/text.c -o /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/text.o /work/fsf-trunk-3/build-arm-none-eabi/install/bin/arm-none-eabi-gcc -B/work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/ld/ -I/work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin -O2 -specs=rdimon.specs -Wa,-mno-warn-deprecated -mthumb -O2 -c /work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/main.c -o /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/main.o /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/ld-new -o /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/main.x -L/work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin -plugin /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/.libs/ -plugin-opt registerclaimfile -plugin-opt registerallsymbolsread -plugin-opt registercleanup -plugin-opt dumpresolutions /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/main.o /work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/func.c /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/text.o --defsym __stack_chk_fail=0 --defsym __gccmain=0 --defsym printf=main --defsym puts=main
hook called: all symbols read.
Input: /work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/func.c (/work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/func.c)
Sym: 'func' Resolution: LDPR_PREVAILING_DEF
Sym: '_func' Resolution: LDPR_PREVAILING_DEF_IRONLY
/work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/ld-new: /work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/func.c (symbol from plugin)(func): warning: interworking not enabled. first occurrence: /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/main.o: Thumb call to ARM /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/ld-new: /work/fsf-trunk-3/src/binutils-gdb/ld/testsuite/ld-plugin/func.c (symbol from plugin)(func): warning: interworking not enabled. first occurrence: /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/main.o: Thumb call to ARM /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/ld-new: warning: cannot find entry symbol _start; defaulting to 0000000000008000 /work/fsf-trunk-3/build-arm-none-eabi/obj/binutils/ld/tmpdir/main.o: In function `main':
main.c:(.text.startup+0xa): undefined reference to `func'
hook called: cleanup.

Kind regards,

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