It's not enough to test that the output is ELF before casting
bfd_link_hash_entry to elf_link_hash_entry. Some ELF targets (d30v,
dlx, pj, s12z, xgate) use the generic linker support in bfd/linker.c
and thus their symbols are of type generic_link_hash_entry.
Not all of the places this patch touches can result in wrong accesses,
but I thought it worth ensuring that all occurrences of
elf_link_hash_entry in ld/ were obviously correct.
PR 27719
* ldlang.c (lang_mark_undefineds, undef_start_stop): Test that
the symbol hash table is the correct type before accessing
elf_link_hash_entry symbols.
* plugin.c (is_visible_from_outside): Likewise.
* emultempl/armelf.em (ld${EMULATION_NAME}_finish): Likewise.
* emultempl/solaris2.em (elf_solaris2_before_allocation): Likewise.
This adds some annotation to Power10 pcrel instructions, displaying
the target address (ie. pc + D34 field) plus a symbol if there is one
at exactly that target address. pld from the .got or .plt will also
look up the entry and display it, symbolically if there is a dynamic
relocation on the entry.
include/
* dis-asm.h (struct disassemble_info): Add dynrelbuf and dynrelcount.
binutils/
* objdump.c (struct objdump_disasm_info): Delete dynrelbuf and
dynrelcount.
(find_symbol_for_address): Adjust for dynrelbuf and dynrelcount move.
(disassemble_section, disassemble_data): Likewise.
opcodes/
* ppc-dis.c (struct dis_private): Add "special".
(POWERPC_DIALECT): Delete. Replace uses with..
(private_data): ..this. New inline function.
(disassemble_init_powerpc): Init "special" names.
(skip_optional_operands): Add is_pcrel arg, set when detecting R
field of prefix instructions.
(bsearch_reloc, print_got_plt): New functions.
(print_insn_powerpc): For pcrel instructions, print target address
and symbol if known, and decode plt and got loads too.
gas/
* testsuite/gas/ppc/prefix-pcrel.d: Update expected output.
* testsuite/gas/ppc/prefix-reloc.d: Likewise.
* gas/testsuite/gas/ppc/vsx_32byte.d: Likewise.
ld/
* testsuite/ld-powerpc/inlinepcrel-1.d: Update expected output.
* testsuite/ld-powerpc/inlinepcrel-2.d: Likewise.
* testsuite/ld-powerpc/notoc2.d: Likewise.
* testsuite/ld-powerpc/notoc3.d: Likewise.
* testsuite/ld-powerpc/pcrelopt.d: Likewise.
* testsuite/ld-powerpc/startstop.d: Likewise.
* testsuite/ld-powerpc/tlsget.d: Likewise.
* testsuite/ld-powerpc/tlsget2.d: Likewise.
* testsuite/ld-powerpc/tlsld.d: Likewise.
* testsuite/ld-powerpc/weak1.d: Likewise.
* testsuite/ld-powerpc/weak1so.d: Likewise.
Due to a bogus linker script, or perhaps because a section doesn't get
placed by a linker script while default placement puts it too high up,
sections can end up above .reloc. Since the process of determining its
contents (and hence its size) happens before final section placement,
relocations needed for such sections would no longer point at the
correct address in the final binary. Warn about this (down the road this
may want to become an error, unless size determination and content
creation for .reloc would get decoupled).
To avoid triggering the warning when .reloc gets discarded, suppress
populating the section in the first place in this case.
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.
The data object and function info sections (collectively "symtypetabs")
usually (i.e. if non-indexed) have sizes defined by the size of the ELF
dynamic symbol table in the object they are linked to. This means test
results should not depend on the exact sizes of these sections, because
adding entirely irrelevant symbols to the dynsym can cause spurious test
failures. (This also means we should not match the offset of sections
that follow them, since those too depend on the exact size of the
symtypetab sections.)
Spotted by turning the sanitizer on, which introduced new dynsym entries
and expanded the symtypetab sizes to match.
ld/ChangeLog
2021-03-25 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/array.d: Only check that the data object
section is nonempty: do not check its exact size.
* testsuite/ld-ctf/diag-parlabel.d: Likewise.
* testsuite/ld-ctf/slice.d: Likewise.
* testsuite/ld-ctf/data-func-conflicted.d: Likewise, and for the
func info section too.
* testsuite/ld-ctf/function.d: Likewise, for the func info section.
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.
The previous commit started to error-check the lookup of
ctf_type_encoding for the underlying type that is internally done when
carrying out a ctf_type_encoding on a slice.
Unfortunately, enums have no encoding, so this has historically been
returning an error (which is ignored) and then populating the cte_format
with uninitialized data. Now the error is not ignored, this is
returning an error, which breaks linking of CTF containing bitfields of
enumerated type.
CTF format v3 does not record the actual underlying type of a enum, but
we can mock up something that is not *too* wrong, and that is at any
rate better than uninitialized data.
ld/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* testsuite/ld-ctf/slice.c: Check slices of enums too.
* testsuite/ld-ctf/slice.d: Results adjusted.
libctf/ChangeLog
2021-03-18 Nick Alcock <nick.alcock@oracle.com>
* ctf-types.c (ctf_type_encoding): Support, after a fashion, for enums.
* ctf-dump.c (ctf_dump_format_type): Do not report enums' degenerate
encoding.
The allocation of reloc_d doesn't take reloc_s->size into account. There
is already padding being emitted up to the allocated size. While
reloc_s->size ought to still be zero at this point anyway (and hence the
code being deleted would have been just dead), don't risk writing past
the actual allocation.
Attempting to build --enable-targets=all on a 32-bit host results in a
number of errors like the following.
eelf32lriscv.o: in function `gldelf32lriscv_after_allocation':
eelf32lriscv.c:98: undefined reference to `bfd_elf32_riscv_restart_relax_sections'
That's due to needing --enable-64-bit-bfd to get the riscv BFD support
built.
* Makefile.am (ALL_EMULATION_SOURCES): Move riscv files to..
(ALL_64_EMULATION_SOURCES): ..here.
* Makefile.in: Regenerate.
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.
Fixes x86_64-w64-mingw32 tests that failed with the recent diagnosis
for out of range RVA, and a couple of other gc-sections tests that failed
for other reasons.
* testsuite/ld-gc/gc.exp: Pass "-image-base 0" to ld for PE, and
arrange to define __main for some run_dump_test tests.
* testsuite/ld-gc/pr13683.d: Accept more symbols.
* testsuite/ld-gc/pr14265.d: Likewise, and ordering.
* testsuite/ld-scripts/crossref.exp: Pass "-image-base 0" to ld for PE.
* testsuite/ld-srec/srec.exp: Likewise.
* testsuite/lib/ld-lib.exp (ld_link_defsyms): Use is_pecoff_format.
According to the commit abd20cb637, an
intersting thing is that - the more relax passes, the more chances of
relaxations are reduced [1]. Originally, we set the boolean `again`
to TRUE once the code is actually deleted, and then we run the relaxations
repeatedly if `again` is still TRUE. But `again` only works for the
relax pass itself, and won't affect others. That is - we can not use
`again` to re-run the relax pass when we already enter into the following
passes (can not run the relax passes backwards). Besides, we must seperate
the PCREL relaxations into two relax passes for some reasons [2], it make
us lose some relax opportunities.
This patch try to fix the problem, and the basic idea was come from Jim
Wilson - we use a new boolean, restart_relax, to determine if we need to
run the whole relax passes again from 0 to 2. Once we have deleted the
code between relax pass 0 to 2, the restart_relax will be set to TRUE,
we should run the whole relaxations again to give them more chances to
shorten the code. We will only enter into the relax pass 3 when the
restart_relax is FALSE, since we can't relax anything else once we start
to handle the alignments.
I have passed the gcc/binutils regressions by riscv-gnu-toolchain, and
looks fine for now.
[1] https://sourceware.org/pipermail/binutils/2020-November/114223.html
[2] https://sourceware.org/pipermail/binutils/2020-November/114235.html
bfd/
* elfnn-riscv.c (riscv_elf_link_hash_table): New boolean restart_relax,
used to check if we need to run the whole relaxations from relax pass 0
to 2 again.
(riscv_elf_link_hash_table_create): Init restart_relax to FALSE.
(_bfd_riscv_relax_align): Remove obsolete sec_flg0 set.
(_bfd_riscv_relax_delete): Set again to TRUE if we do delete the code.
(bfd_elfNN_riscv_restart_relax_sections): New function. Called by
after_allocation to check if we need to run the whole relaxations again.
(_bfd_riscv_relax_section): We will only enter into the relax pass 3 when
the restart_relax is FALSE; At last set restart_relax to TRUE if again is
TRUE, too.
* elfxx-riscv.h (bfd_elf32_riscv_restart_relax_sections): Declaration.
(bfd_elf64_riscv_restart_relax_sections): Likewise.
ld/
* emultempl/riscvelf.em (after_allocation): Run ldelf_map_segments many
times if riscv_restart_relax_sections returns TRUE.
* testsuite/ld-riscv-elf/restart-relax.d: New testcase. Before applying
this patch, the call won't be relaxed to jal; But now we have more chances
to do relaxations.
* testsuite/ld-riscv-elf/restart-relax.s: Likewise.
* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
The offset-within-section field in the symbol table entry is only 32
bits wide, so rather than emitting bogus entries omit them, and issue
a diagnostic identifying the issue.
This requires adjusting the PR/22267 test to no longer produce symbols
with out of range values on 64-bit BFD. This also depends on
adjustments to testsuite/ld-scripts/map-address.* made by an earlier
patch. The purpose of the test can very well be achieved nevertheless.
mcore-pe and sh-pe pointed out that the testcase added by 6fa7408d72
("ld: don't generate base relocations in PE output for absolute
symbols") wasn't quite generic enough yet. Copy entry point stuff from
another test and increase alignment to also cover targets with a page
size lower than 4k.
Despite all of this the test needs to be xfail-ed for mcore, as this
target isn't included in the set getting DLL_SUPPORT enabled in
emultempl/pe.em, and hence no base relocations get generated there
(yet).
In PE images section addresses get expressed as addresses relative to
the image base. Therefore the VA of a section must be no less than the
image base, and after subtraction of the image base the resulting value
should fit in 32 bits. (The issue is particularly obvious to notice when
sections, perhaps because of ELF assumptions, get placed at VA 0 by
default. Debugging info sections as well as .comment, when input files
are ELF, are a good example. All such sections need proper mentioning in
the linker script to avoid this warning.)
There are a number of test cases which previously produced bogus images,
yet still declared the test a success. Like done for other tests
already, force a zero image base for these. This then also allows (and
requires) dropping again xfail-s which 39a7b38fac ("Fix linker tests
to work with 16-bit targets") had added to ld-scripts/default-script*.d
(originally as skip-s). This also depends on similar adjustments to
testsuite/ld-scripts/map-address.* made by an earlier patch.
For ld-scripts/print-memory-usage.* I suppose xcoff could be dropped
from the exclusion list by suppressing garbage collection, just like
already done in e.g. (as seen in the diff here) ld-scripts/data.*, but I
didn't want to make unrelated adjustments.
When linking Windows x86-64 relocatable object files to generate x86-64
ELF executable, we need to subtract __ImageBase, aka __executable_start,
for R_AMD64_IMAGEBASE relocation:
1. Add link_info to struct output_elf_obj_tdata to store linker info and
_bfd_get_link_info() to retrieve it.
2. Add ldelf_set_output_arch to set up link_info.
3. Add pex64_link_add_symbols to create an indirect reference to
__executable_start for __ImageBase to support R_AMD64_IMAGEBASE relocation
when adding symbols from Windows x86-64 relocatable object files to
generate x86-64 ELF executable.
4. Also subtract __ImageBase for R_AMD64_IMAGEBASE when generating x86-64
ELF executable.
bfd/
PR ld/27425
PR ld/27432
* bfd.c (_bfd_get_link_info): New function.
* elf-bfd.h (output_elf_obj_tdata): Add link_info.
(elf_link_info): New.
* libbfd-in.h (_bfd_get_link_info): New prototype.
* coff-x86_64.c (coff_amd64_reloc): Also subtract __ImageBase for
R_AMD64_IMAGEBASE when generating x86-64 ELF executable.
* pe-x86_64.c: Include "coff/internal.h" and "libcoff.h".
(pex64_link_add_symbols): New function.
(coff_bfd_link_add_symbols): New macro.
* libbfd.h: Regenerated.
ld/
PR ld/27425
PR ld/27432
* ldelf.c (ldelf_set_output_arch): New function.
* ldelf.h (ldelf_set_output_arch): New prototype.
* emultempl/elf.em (LDEMUL_SET_OUTPUT_ARCH): Default to
ldelf_set_output_arch.
* ld-x86-64/pe-x86-64-1.od: Expect __executable_start.
* testsuite/ld-x86-64/pe-x86-64-2.od: Likewise.
* testsuite/ld-x86-64/pe-x86-64-3.od: Likewise.
* testsuite/ld-x86-64/pe-x86-64-4.od: Likewise.
* testsuite/ld-x86-64/pe-x86-64-5.od: Likewise.
* testsuite/ld-x86-64/pe-x86-64-5.rd: Likewise.
* testsuite/ld-x86-64/pe-x86-64-6.obj.bz2: New file.
* testsuite/ld-x86-64/pe-x86-64-6.od: Likewise.
* testsuite/ld-x86-64/pe-x86-64.exp: Run ld/27425 test.
Without setting an image base address and without naming at least .text,
this test produces entirely bogus PE output. To be honest, even the ELF
output looks odd: .text gets placed at 0x10204, and both foo and bar get
associated with .text despite living below its start address.
Since neither image base nor .text placement are the subject of this
test, specify .text placement explicitly and in the PE case force the
image base to zero.
It is the very nature of absolute symbols that they don't change even
if the loader decides to put the image at other than its link-time base
address. Of the linker-defined (and PE-specific) symbols __image_base__
(and its alias) needs special casing, as it'll still appear to be
absolute at this point.
A new inquiry function in ldexp.c is needed because PE base relocations
get generated before ldexp_finalize_syms() runs, yet whether a
relocation is needed depends on the ultimate property of a symbol.
The testcases added here show situations where synthesized start/stop
symbols don't cause their associated input sections to be marked.
Fixed with the elflink.c and ldlang.c changes.
bfd/
PR 27500
* elflink.c (_bfd_elf_gc_mark_rsec): Do special start/stop
processing not when start/stop symbol section is unmarked but
on first time a start/stop symbol is processed.
ld/
* ldlang.c (insert_undefined): Don't mark symbols here.
(lang_mark_undefineds): Do so here instead, new function.
(lang_process): Call lang_mark_undefineds.
* testsuite/ld-gc/start3.d,
* testsuite/ld-gc/start3.s: New test.
* testsuite/ld-gc/start4.d,
* testsuite/ld-gc/start4.s: New test.
* testsuite/ld-gc/gc.exp: Run them.
Adjust tests to reference __start and __stop syms with an extra
leading underscore when appropriate, and run tests on more targets.
* testsuite/ld-gc/gc.exp: Define UNDERSCORE in ASFLAGS.
Move tests with ELF section directives to is_elf_format block.
* testsuite/ld-gc/abi-note.d: Run on more targets.
* testsuite/ld-gc/pr19167.d: Likewise and adjust xfails.
* testsuite/ld-gc/start.d: Likewise.
* testsuite/ld-gc/start2.d: Likewise.
* testsuite/ld-gc/stop.d: Likewise.
* testsuite/ld-gc/pr19167a.s: Add support for underscore targets.
* testsuite/ld-gc/start.s: Likewise.
* testsuite/ld-gc/start2.s: Likewise.
This is a tricky one. BFD, on the linker's behalf, reports symbols to
libctf via the ctf_new_symbol and ctf_new_dynsym callbacks, which
ultimately call ctf_link_add_linker_symbol. But while this happens
after strtab offsets are finalized, it happens before the .dynstr is
actually laid out, so we can't iterate over it at this stage and
it is not clear what the reported symbols are actually called. So
a second callback, examine_strtab, is called after the .dynstr is
finalized, which calls ctf_link_add_strtab and ultimately leads
to ldelf_ctf_strtab_iter_cb being called back repeatedly until the
offsets of every string in the .dynstr is passed to libctf.
libctf can then use this to get symbol names out of the input (which
usually stores symbol types in the form of a name -> type mapping at
this stage) and extract the types of those symbols, feeding them back
into their final form as a 1:1 association with the real symtab's
STT_OBJ and STT_FUNC symbols (with a few skipped, see
ctf_symtab_skippable).
This representation is compact, but has one problem: if libctf somehow
gets confused about the st_type of a symbol, it'll stick an entry into
the function symtypetab when it should put it into the object
symtypetab, or vice versa, and *every symbol from that one on* will have
the wrong CTF type because it's actually looking up the type for a
different symbol.
And we have just such a bug. ctf_link_add_strtab was not taking the
refcounts of strings into consideration, so even strings that had been
eliminated from the strtab by virtue of being in objects eliminated via
--as-needed etc were being reported. This is harmful because it can
lead to multiple strings with the same apparent offset, and if the last
duplicate to be reported relates to an eliminated symbol, we look up the
wrong symbol from the input and gets its type wrong: if it's unlucky and
the eliminated symbol is also of the wrong st_type, we will end up with
a corrupted symtypetab.
Thankfully the wrong-st_type case is already diagnosed by a
this-can-never-happen paranoid warning:
CTF warning: Symbol 61a added to CTF as a function but is of type 1
or the converse
* CTF warning: Symbol a3 added to CTF as a data object but is of type 2
so at least we can tell when the corruption has spread to more than one
symbol's type.
Skipping zero-refcounted strings is easy: teach _bfd_elf_strtab_str to
skip them, and ldelf_ctf_strtab_iter_cb to loop over skipped strings
until it falls off the end or finds one that isn't skipped.
bfd/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* elf-strtab.c (_bfd_elf_strtab_str): Skip strings with zero refcount.
ld/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ldelfgen.c (ldelf_ctf_strtab_iter_cb): Skip zero-refcount strings.
libctf/ChangeLog
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* ctf-create.c (symtypetab_density): Report the symbol name as
well as index in the name != object error; note the likely
consequences.
* ctf-link.c (ctf_link_shuffle_syms): Report the symbol index
as well as name.
PowerPC64 has its own gc_mark_dynamic_ref.
bfd/
PR 27451
* elf64-ppc.c (ppc64_elf_gc_mark_dynamic_ref): Ignore synthesized
linker defined start/stop symbols when start_stop_gc.
ld/
* testsuite/ld-powerpc/startstop.d,
* testsuite/ld-powerpc/startstop.r,
* testsuite/ld-powerpc/startstop.s: New test.
* testsuite/ld-powerpc/powerpc.exp: Run it.
Undefined weak symbols with non-default visibility are seen as local
by SYMBOL_REFERENCES_LOCAL. This stops a got indirect to relative
optimisation for them, so that pies and dlls don't get non-zero values
when loading somewhere other than the address they are linked at
(which always happens). The optimisation could be allowed for pdes,
but I thought it best not to allow it there too.
bfd/
* elf64-ppc.c (ppc64_elf_relocate_section): Don't optimise got
indirect to pc-relative or toc-relative for undefined symbols.
ld/
* testsuite/ld-powerpc/weak1.d,
* testsuite/ld-powerpc/weak1.r,
* testsuite/ld-powerpc/weak1.s,
* testsuite/ld-powerpc/weak1so.d,
* testsuite/ld-powerpc/weak1so.r: New tests.
* testsuite/ld-powerpc/powerpc.exp: Run them.
When --gc-sections is in effect, a reference from a retained section
to __start_SECNAME or __stop_SECNAME causes all input sections named
SECNAME to also be retained, if SECNAME is representable as a C
identifier and either __start_SECNAME or __stop_SECNAME is synthesized
by the linker. Add an option to disable that feature, effectively
ignoring any relocation that references a synthesized linker defined
__start_ or __stop_ symbol.
PR 27451
include/
* bfdlink.h (struct bfd_link_info): Add start_stop_gc.
bfd/
* elflink.c (_bfd_elf_gc_mark_rsec): Ignore synthesized linker
defined start/stop symbols when start_stop_gc.
(bfd_elf_gc_mark_dynamic_ref_symbol): Likewise.
(bfd_elf_define_start_stop): Don't modify ldscript_def syms.
* linker.c (bfd_generic_define_start_stop): Likewise.
ld/
* emultempl/elf.em: Handle -z start-stop-gc and -z nostart-stop-gc.
* lexsup.c (elf_static_list_options): Display help for them. Move
help for -z stack-size to here from elf_shlib_list_options. Add
help for -z start-stop-visibility and -z undefs.
* ld.texi: Document -z start-stop-gc and -z nostart-stop-gc.
* NEWS: Mention -z start-stop-gc.
* testsuite/ld-gc/start2.s,
* testsuite/ld-gc/start2.d: New test.
* testsuite/ld-gc/gc.exp: Run it.
If a weak reference to a __start_foo or __stop_foo symbol ends up
having no definition due to all the foo sections being removed for
some reason, undef_start_stop currently makes the symbol strong
undefined. That risks a linker undefined symbol error. Fix that by
making the symbol undefweak and also undo some dynamic symbol state.
Note that saving the state of the symbol type at the time
lang_init_start_stop runs is not sufficient. The linker may have
merged in a shared library reference by that point and made what was
an undefweak in regular objects, a strong undefined. So it is
necessary to look at the ELF symbol flags to decide whether an
undefweak is the proper resolution.
Something probably should be done for COFF/PE too, but I'm unsure how
to do go about that.
* ldlang.c (undef_start_stop): For ELF make undefined start/stop
symbols undefweak if that was how they were referenced. Undo
dynamic state too.
Note that we don't even warn if scripts adjust a symbol as in
ld-elf/var1 and ld-scripts/pr14962.
include/
* bfdlink.h (struct bfd_link_info): Add warn_multiple_definition.
ld/
* ldexp.c (exp_fold_tree_1): Warn on script defining a symbol
defined in an object file.
* ldmain.c (multiple_definition): Heed info->warn_multiple_definition.
* testsuite/ld-scripts/defined5.d: Expect a warning.
When building 32-bit binutils with CC="gcc -m32" CXX="g++ -m32" we can
fail the gcc ld version test due to an error attempting to load a
64-bit plugin into 32-bit ld-new. This results in bogus errors about
"Your compiler driver ignores -B when choosing ld."
* testsuite/lib/ld-lib.exp: Whitespace.
(load_common_lib): Expand single use and delete this proc.
(run_host_cmd): Use -fno-lto when getting gcc's ld version.
Use -B for clang too.
