The change in PR19011 changed the image load address from being in the lower
32-bit address space to the higher 64-bit address space.
However when you have a weak undef symbol which stays undef at the end of
linking the linker has to resolve this (Windows loader does not support undef
symbols). As such typically these would resolve to 0.
The relocation used for these weak symbols are the normal 32-bit PC_REL call
relocs. So when doing the overflow check LD checks if the distance between the
symbol and the call is within range. However now that the load address is
> 32-bits and the symbol val is 0 this overflow check will always fail.
As such the linker gives a bogus error. This patch makes the linker not emit
the overflow failure but chooses to still let the check be performed (as it's
mid-end code).
One down side of this is that it does break the common convention that the call
be to sym at 0x0. i.e. before you'd get
401015: 74 05 je 40101c
401017: e8 e4 ef bf ff callq 0
and now you get
140001015: 74 05 je 14000101c
140001017: e8 e4 ef ff bf call 100000000
since the call is PC_REL there's no way to get the range large enough to
resolve to 0. As such I have chosen to leave it as the furthest simple range
that we can still represent.
By only ignoring the error we leave the symbol value itself to still be 0
such that the if(<symbol>) checks still work correctly.
bfd/ChangeLog:
2021-04-01 Tamar Christina <tamar.christina@arm.com>
PR ld/26659
* cofflink.c (_bfd_coff_generic_relocate_section): Ignore overflow.
ld/ChangeLog:
2021-04-01 Tamar Christina <tamar.christina@arm.com>
PR ld/26659
* testsuite/ld-pe/pe.exp: Add test.
* testsuite/ld-pe/pr26659-weak-undef-sym.d: New test.
* testsuite/ld-pe/pr26659-weak-undef-sym.s: New test.
With this in place we can retire bfd_boolean one project at a time.
bfd/
* bfd-in.h: Include stdbool.h.
(bfd_boolean): Define as bool
* bfd-in2.h: Regenerate.
This fixes the issue that startswith depends on strncpy being
declared, and not all projects using bfd.h include string.h before
bfd.h. I've also deleted some macros that don't find much use
anywhere.
bfd/
* bfd-in.h: Include string.h.
(LITMEMCPY, LITSTRCPY): Delete.
* bfd-in2.h: Regenerate.
binutils/
* prdbg.c (pr_function_type): Replace LITSTTCPY with strcpy.
Seen after converting bfd_boolean to bool.
mmix +FAIL: ld-mmix/zeroehmmo
./ld-new -L/home/alan/src/binutils-gdb/ld/testsuite/ld-mmix -m mmo -Ttext 0xa00 -T /home/alan/src/binutils-gdb/ld/testsuite/ld-mmix/zeroeh.ld -o tmpdir/dump tmpdir/x.o tmpdir/y.o
/home/alan/src/binutils-gdb/bfd/linker.c:2294:8: runtime error: load of value 253, which is not a valid value for type '_Bool'
* elflink.c (elf_link_add_object_symbols): Don't set h->indx
unless is_elf_hash_table.
elf_backend_link_output_symbol_hook and elf_link_output_symstrtab may
return 2 when a symbol is to be discarded. Update places that use
bfd_boolean rather than int for these functions.
* elflink.c (elf_link_output_symstrtab): Make flinfo parameter
a void pointer.
(bfd_elf_final_link): Delete out_sym_func typedef and don't cast
elf_link_output_symstrtab when calling output_arch_syms and
output_arch_local_syms.
* elf-bfd.h (struct elf_backend_data <elf_backend_output_arch_syms,
elf_backend_output_arch_local_syms>): Change return type of func
arg to match elf_link_output_symstrtab.
* elf-vxworks.h (elf_vxworks_link_output_symbol_hook): Correct
return type.
* elf32-nds32.c (nds32_elf_output_symbol_hook): Correct return type.
(nds32_elf_output_arch_syms): Correct func return type.
A recent bug (RH BZ 1931344) has exposed a bug in the core file
build-ID support that I introduced a while ago. It is pretty
easy to demonstate the problem following a simplified procedure
outlined in that bug:
[shell1]
shell1$ /usr/libexec/qemu-kvm
[shell2]
shell2$ pkill -SEGV -x qemu-kvm
[shell1]
Segmentation fault (core dumped)
Load this core file into GDB without specifying an executable
(an unfortunate Fedora/RHEL-ism), and GDB will inform the user
to install debuginfo for the "missing" executable:
$ gdb -nx -q core.12345
...
Missing separate debuginfo for the main executable file
Try: dnf --enablerepo='*debug*' install /usr/lib/debug/.build-id/e2/e9c66d3117fb2bbb5b2be122f04f2664e5df54
Core was generated by `/usr/libexec/qemu-kvm'.
Program terminated with signal SIGSEGV, Segmentation fault.
...
The suggested build-ID is actaully for gmp not qemu-kvm. The problem
lies in _bfd_elf_core_find_build_id, where we loop over program headers
looking for note segments:
/* Read in program headers and parse notes. */
for (i = 0; i < i_ehdr.e_phnum; ++i, ++i_phdr)
{
Elf_External_Phdr x_phdr;
if (bfd_bread (&x_phdr, sizeof (x_phdr), abfd) != sizeof (x_phdr))
goto fail;
elf_swap_phdr_in (abfd, &x_phdr, i_phdr);
if (i_phdr->p_type == PT_NOTE && i_phdr->p_filesz > 0)
{
elf_read_notes (abfd, offset + i_phdr->p_offset,
i_phdr->p_filesz, i_phdr->p_align);
if (abfd->build_id != NULL)
return TRUE;
}
elf_read_notes uses bfd_seek to forward the stream to the location of
the note segment. When control returns to _bfd_elf_core_fild_build_id,
the stream is no longer in the location looking at program headers, and
all subsequent reads will read from the wrong file offset.
To fix this, this patch marks the stream location and ensures
that it is restored after elf_read_notes is called.
bfd/ChangeLog
2021-03-26 Keith Seitz <keiths@redhat.com>
* elfcore.h (_bfd_elf_core_find_build_id): Seek file
offset of program headers after calling elf_read_notes.
bfd/
* bfd-in.h (startswith): New inline.
(CONST_STRNEQ): Use startswith.
* bfd-in2.h: Regenerate.
gdbsupport/
* common-utils.h (startswith): Delete version now supplied by bfd.h.
libctf/
* ctf-impl.h: Include string.h.
The exception for debug sections in clearing SEC_EXCLUDE when
relocatable was really for one specific debug section, so let's make
it do just that.
bfd/
PR 27590
* elf.c (_bfd_elf_make_section_from_shdr): Remove SHF_EXCLUDE
test for .gnu.debuglto*.
ld/
PR 27590
* ldlang.c (lang_gc_sections): Clear SEC_EXCLUDE when relocatable
for all sections except .stabstr.
commit 994b251328
Author: H.J. Lu <hjl.tools@gmail.com>
Date: Sun Jan 17 20:01:16 2021 -0800
ld/elf: Ignore section symbols when matching linkonce with comdat
ignored section symbols when comparing symbols in 2 sections. Since all
references to debugging sections are done with section symbols, symbols
in debugging sections are ignored and we fail to match symbols in comdat
debugging sections. Also .gnu.debuglto_.debug_* sections aren't treated
as debugging sections.
1. Treate .gnu.debuglto_.debug_ section as debugging section unless it
is marked with SHF_EXCLUDE.
2. Revert commit 994b251328 in elf_create_symbuf.
3. Ignore section symbols only when matching non-debugging sections or
linkonce section with comdat section.
bfd/
PR ld/27590
* elf.c (_bfd_elf_make_section_from_shdr): Treate
.gnu.debuglto_.debug_ section as debugging section unless it is
marked with SHF_EXCLUDE.
* elflink.c (elf_create_symbuf): Revert commit 994b251328.
(bfd_elf_match_symbols_in_sections): Ignore section symbols when
matching non-debugging sections or linkonce section with comdat
section.
ld/
PR ld/27590
* testsuite/ld-elf/pr27590.s: New file.
* testsuite/ld-elf/pr27590a.d: Likewise.
* testsuite/ld-elf/pr27590b.d: Likewise.
* testsuite/ld-i386/i386.exp: Also run ld/27193 test with
--reduce-memory-overheads.
* peXXigen.c (_bfd_XXi_swap_aux_out): Avoid potential buffer
overrun by using sizeof of the destination x_fname field as the
limit for a memcpy.
* coff/internal.h (struct internal_auxent): Fix a couple of typos
in comment describing the x_fname field.
Add support for TLS in XCOFF. Amongst the things done by this commit:
- Update XCOFF auxialiary header to match new version and allow TLS
sections.
- Add TLS sections (.tdata and .tbss) support in gas and ld.
- Add support for the TLS relocations in gas and ld.
Two different types BFD_RELOC are created for PPC and PPC64 as
the size is a pointer, thus distinct in 32 or 64bit.
The addresses given by ld to .tdata and .tbss is a bit special. In
XCOFF, these addresses are actually offsets from the TLS pointer
computed at runtime. AIX assembly and linker does the same. In
top of that, the .tdata must be before .data (this is mandatory for AIX
loader). Thus, the aix ld script is recomputing "." before .data to restore
its original value. There might be a simpler way, but this one is working.
Optimisation linked to TLS relocations aren't yet implemented.
bfd/
* reloc.c (BFD_RELOC_PPC_TLS_LE, BFD_RELOC_PPC_TLS_IE,
BFD_RELOC_PPC_TLS_M, BFD_RELOC_PPC_TLS_ML, BFD_RELOC_PPC64_TLS_GD,
BFD_RELOC_PPC64_TLS_LD, BFD_RELOC_PPC64_TLS_LE,
BFD_RELOC_PPC64_TLS_IE, BFD_RELOC_PPC64_TLS_M,
BFD_RELOC_PPC64_TLS_ML): New relocations.
* bfd-in2.h: Regenerate.
* libbfd.h: Regenerate.
* coff-rs6000.c (xcoff_calculate_relocation): Call
xcoff_reloc_type_tls for TLS relocations.
(xcoff_howto_table): Implement TLS relocations.
(_bfd_xcoff_reloc_type_lookup): Add cases TLS relocations.
(xcoff_reloc_type_tls): New function.
* coff64-rs6000.c (xcoff_calculate_relocation): Likewise.
(xcoff_howto_table): Likewise.
(_bfd_xcoff_reloc_type_lookup): Likewise.
* coffcode.h (sec_to_styp_flags): Handle TLS sections.
(styp_to_sec_flags): Likewise.
(coff_compute_section_file_positions): Avoid file offset
optimisation for .data when the previous section is .tdata.
(coff_write_object_contents): Handle TLS sections.
* coffswap.h (coff_swap_aouthdr_out): Add support for
new fields in aouthdr.
* libxcoff.h (xcoff_reloc_type_tls): Add prototype.
* xcofflink.c (xcoff_link_add_symbols): Handle XMC_UL.
(xcoff_need_ldrel_p): Add cases for TLS relocations.
(xcoff_create_ldrel): Add l_symndx for TLS sections.
gas/
* config/tc-ppc.c (ppc_xcoff_text_section, ppc_xcoff_data_section,
(ppc_xcoff_bss_section, ppc_xcoff_tdata_section,
(ppc_xcoff_tbss_section): New variables.
(ppc_text_subsegment, ppc_text_csects, ppc_data_subgments,
(ppc_data_csects): Removed.
(ppc_xcoff_section_is_initialized, ppc_init_xcoff_section,
ppc_xcoff_parse_cons): New functions.
(md_being): Initialize XCOFF sections.
(ppc_xcoff_suffix): Add support for TLS relocations
(fixup_size, md_apply_fix): Add support for new BFD_RELOC.
(ppc_change_csect): Handle XMC_TL, XMC_UL. Correctly, add XMC_BS
to .bss section. Handle new XCOFF section variables.
(ppc_comm): Likewise.
(ppc_toc): Likewise.
(ppc_symbol_new_hook): Likewise.
(ppc_frob_symbol): Likewise.
(ppc_fix_adjustable): Add tbss support.
* config/tc-ppc.h (TC_PARSE_CONS_EXPRESSION): New define.
(ppc_xcoff_parse_cons): Add prototype.
(struct ppc_xcoff_section): New structure.
ld/
* emultempl/aix.em: Ensure .tdata section is removed
if empty, even with -r flag.
* scripttempl/aix.sc: Handle TLS sections.
* testsuite/ld-powerpc/aix52.exp: Add new tests.
* testsuite/ld-powerpc/aix-tls-reloc-32.d: New test.
* testsuite/ld-powerpc/aix-tls-reloc-64.d: New test.
* testsuite/ld-powerpc/aix-tls-reloc.ex: New test.
* testsuite/ld-powerpc/aix-tls-reloc.s: New test.
* testsuite/ld-powerpc/aix-tls-section-32.d: New test.
* testsuite/ld-powerpc/aix-tls-section-64.d: New test.
* testsuite/ld-powerpc/aix-tls-section.ex: New test.
* testsuite/ld-powerpc/aix-tls-section.s: New test.
include/
* coff/internal.h (struct internal_aouthdr): Add new fields.
* coff/rs6000.h (AOUTHDRÃ): Add new fields.
* coff/rs6k64.h (struct external_filehdr): Likewise.
* coff/xcoff.h (_TDATA), _TBSS): New defines
(RS6K_AOUTHDR_TLS_LE, RS6K_AOUTHDR_RAS, RS6K_AOUTHDR_ALGNTDATA,
RS6K_AOUTHDR_SHR_SYMTAB, RS6K_AOUTHDR_FORK_POLICY,
RS6K_AOUTHDR_FORK_COR): New defines.
(XMC_TU): Removed.
(XMC_UL): New define.
Implement support for largetoc on XCOFF.
R_TOCU and R_TOCL are referenced by the new BFD defines:
BFD_RELOC_PPC_TOC16_HI and BFD_RELOC_PPC_TOC16_LO.
A new toc storage class is added XMC_TE.
In order to correctly handle R_TOCU, the logic behind
xcoff_reloc_type_toc is changed to compute the whole TOC offset
instead of just the difference between the "link" offset and the
"assembly" offset.
In gas, add a function to transform addis format used by AIX
"addis RT, D(RA)" into the ELF format "addis RT, RA, SI".
bfd/
* reloc.c (BFD_RELOC_PPC_TOC16_HI, BFD_RELOC_PPC_TOC16_LO):
New relocations.
* bfd-in2.h: Regenerate.
* libbfd.h: Regenerate.
* coff-rs6000.c (xcoff_calculate_relocation): Call
xcoff_reloc_type_toc for R_TOCU and R_TOCL.
(xcoff_howto_table): Remove src_mask for TOC relocations.
Add R_TOCU and R_TOCL howtos.
(_bfd_xcoff_reloc_type_lookup): Add cases for
BFD_RELOC_PPC_TOC16_HI and BFD_RELOC_PPC_TOC16_LO.
(xcoff_reloc_type_toc): Compute the whole offset.
Implement R_TOCU and R_TOCL.
* coff64-rs6000.c (xcoff64_calculate_relocation):
Likewise.
(xcoff64_howto_table): Likewise.
(xcoff64_reloc_type_lookup): Likewise.
gas/
* config/tc-ppc.c (ppc_xcoff_suffix): New function.
(MAP, MAP32, MAP64): New macros for XCOFF.
(ppc_xcoff_fixup_addis): New function.
(ppc_is_toc_sym): Handle XMC_TE.
(fixup_size): Add cases for BFD_RELOC_PPC_TOC16_HI and
BFD_RELOC_PPC_TOC16_LO.
(md_assemble): Call ppc_xcoff_fixup_addis for XCOFF.
(ppc_change_csect): Handle XMC_TE.
(ppc_tc): Enable .tc symbols to have only a XMC_TC or XMC_TE
storage class.
(ppc_symbol_new_hook): Handle XMC_TE.
(ppc_frob_symbol): Likewise.
(ppc_fix_adjustable): Likewise.
(md_apply_fix): Handle BFD_RELOC_PPC_TOC16_HI and
BFD_RELOC_PPC_TOC16_LO.
ld/
* scripttempl/aix.sc: Add .te to .data section.
* testsuite/ld-powerpc/aix52.exp: Add test structure for AIX7+.
Add aix-largetoc-1 test.
* testsuite/ld-powerpc/aix-largetoc-1-32.d: New test.
* testsuite/ld-powerpc/aix-largetoc-1-64.d: New test.
* testsuite/ld-powerpc/aix-largetoc-1.ex: New test.
* testsuite/ld-powerpc/aix-largetoc-1.s: New test.
