Commit 325ba6fb34 excluded degenerate zero length PT_LOAD segments,
but that only fixed part of the problem, which was that the load
segment limits were not calculated properly.
PR 22845
* elf.c (IS_TBSS): Define.
(_bfd_elf_map_sections_to_segments): Use IS_TBSS.
(assign_file_positions_for_non_load_sections): Revert last change.
Properly calculate load segment limits to compare against relro limits.
Fixes a failure triggered by -z separate-code. p_memsz is tested
rather than p_filesz for objcopy --only-keep-debug where p_filesz is
set to zero.
PR 22845
* elf.c (assign_file_positions_for_non_load_sections): Ignore
degenerate zero size PT_LOAD segments when finding one overlapping
the PT_GNU_RELRO segment.
bfd/
* elfnn-riscv.c (riscv_elf_relocate_section): Use bfd_reloc_dangerous
when pcrel_lo reloc has an addend. Use reloc_dangerous callback for
bfd_reloc_dangerous. Use einfo instead of warning callback for errors.
Add %X%P to error messages.
ld/
* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Run pcrel-lo-addend test.
* testsuite/ld-riscv-elf/pcrel-lo-addend.d: New.
* testsuite/ld-riscv-elf/pcrel-lo-addend.s: New.
The fix for PR ld/22727 on SPARC passed TRUE as the 'create' argument
in the call to bfd_link_hash_lookup. It turns out this was a bad idea
because, if the symbol is created at this point, the link will abort
later in elf_link_output_extsym. This changes the TRUE into a FALSE
and puts an assertion on the result of the call, making it easier to
debug the issue; that's exactly in keeping with what Gold does.
bfd/
* elfxx-sparc.c (_bfd_sparc_elf_check_relocs) <R_SPARC_TLS_GD_CALL>:
Pass FALSE instead of TRUE as 'create' argument to bfd_link_hash_lookup
and assert that the result of the call is not NULL.
Since PLT in PDE and PC-relative PLT in PIE can be used as function
address, there is no need for dynamic PC-relative relocation against
a dynamic function definition in PIE. Linker should resolve PC-relative
reference to its PLT address.
NB: i386 has non-PIC PLT and PIC PLT. Only non-PIC PLT in PDE can
be used as function address. PIC PLT in PIE can't be used as
function address.
bfd/
PR ld/22842
* elf32-i386.c (elf_i386_check_relocs): Pass FALSE for non
PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
* elf64-x86-64.c (elf_x86_64_check_relocs): Create PLT for
R_X86_64_PC32 reloc against dynamic function in data section.
Pass TRUE for PC-relative PLT to NEED_DYNAMIC_RELOCATION_P.
(elf_x86_64_relocate_section): Use PLT for R_X86_64_PC32 reloc
against dynamic function in data section.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Use PLT in PIE as
function address only if pcrel_plt is true.
(_bfd_x86_elf_link_hash_table_create): Set pcrel_plt.
* elfxx-x86.h (NEED_DYNAMIC_RELOCATION_P): Add PCREL_PLT for
PC-relative PLT. If PLT is PC-relative, don't generate dynamic
PC-relative relocation against a function definition in data
secton in PIE. Remove the obsolete comments.
(elf_x86_link_hash_table): Add pcrel_plt.
ld/
PR ld/22842
* testsuite/ld-i386/i386.exp: Run PR ld/22842 tests.
* testsuite/ld-x86-64/x86-64.exp: Likewise.
* testsuite/ld-i386/pr22842a.c: New file.
* testsuite/ld-i386/pr22842b.S: Likewise.
* testsuite/ld-x86-64/pr22842a.c: Likewise.
* testsuite/ld-x86-64/pr22842a.rd: Likewise.
* testsuite/ld-x86-64/pr22842b.S: Likewise.
* testsuite/ld-x86-64/pr22842b.rd: Likewise.
If a symbol is not defined in a regular file, and we are not generating
a shared library, then set the symbol to its location in the .plt. This
is required to make function pointers compare as equal between the normal
executable and the shared library.
* elfxx-x86.c (elf_x86_allocate_dynrelocs): Check bfd_link_dll,
instead of bfd_link_pic, for building shared library.
Since there is no need to prepare for PLT branch on x86-64, generate
R_X86_64_PLT32, instead of R_X86_64_PC32, if possible, which can be
used as a marker for 32-bit PC-relative branches.
To compile Linux kernel, this patch:
From: "H.J. Lu" <hjl.tools@gmail.com>
Subject: [PATCH] x86: Treat R_X86_64_PLT32 as R_X86_64_PC32
On i386, there are 2 types of PLTs, PIC and non-PIC. PIE and shared
objects must use PIC PLT. To use PIC PLT, you need to load
_GLOBAL_OFFSET_TABLE_ into EBX first. There is no need for that on
x86-64 since x86-64 uses PC-relative PLT.
On x86-64, for 32-bit PC-relative branches, we can generate PLT32
relocation, instead of PC32 relocation, which can also be used as
a marker for 32-bit PC-relative branches. Linker can always reduce
PLT32 relocation to PC32 if function is defined locally. Local
functions should use PC32 relocation. As far as Linux kernel is
concerned, R_X86_64_PLT32 can be treated the same as R_X86_64_PC32
since Linux kernel doesn't use PLT.
is needed. It is available on hjl/plt32/master branch at
https://github.com/hjl-tools/linux
bfd/
PR gas/22791
* elf64-x86-64.c (is_32bit_relative_branch): Removed.
(elf_x86_64_relocate_section): Check PIC relocations in PIE.
Remove is_32bit_relative_branch usage. Disallow PC32 reloc
against protected function in shared object.
gas/
PR gas/22791
* config/tc-i386.c (need_plt32_p): New function.
(output_jump): Generate BFD_RELOC_X86_64_PLT32 if possible.
(md_estimate_size_before_relax): Likewise.
* testsuite/gas/i386/reloc64.d: Updated.
* testsuite/gas/i386/x86-64-jump.d: Likewise.
* testsuite/gas/i386/x86-64-mpx-branch-1.d: Likewise.
* testsuite/gas/i386/x86-64-mpx-branch-2.d: Likewise.
* testsuite/gas/i386/x86-64-relax-2.d: Likewise.
* testsuite/gas/i386/x86-64-relax-3.d: Likewise.
* testsuite/gas/i386/ilp32/reloc64.d: Likewise.
* testsuite/gas/i386/ilp32/x86-64-branch.d: Likewise.
ld/
PR gas/22791
* testsuite/ld-x86-64/mpx1c.rd: Updated.
* testsuite/ld-x86-64/pr22791-1.err: New file.
* testsuite/ld-x86-64/pr22791-1a.c: Likewise.
* testsuite/ld-x86-64/pr22791-1b.s: Likewise.
* testsuite/ld-x86-64/pr22791-2.rd: Likewise.
* testsuite/ld-x86-64/pr22791-2a.s: Likewise.
* testsuite/ld-x86-64/pr22791-2b.c: Likewise.
* testsuite/ld-x86-64/pr22791-2c.s: Likewise.
* testsuite/ld-x86-64/x86-64.exp: Run PR ld/22791 tests.
Remove `-Wshadow' compilation errors:
cc1: warnings being treated as errors
.../bfd/wasm-module.c: In function 'wasm_scan_name_function_section':
.../bfd/wasm-module.c:312: error: declaration of 'index' shadows a global declaration
/usr/include/string.h:303: error: shadowed declaration is here
.../bfd/wasm-module.c: In function 'wasm_register_section':
.../bfd/wasm-module.c:494: error: declaration of 'index' shadows a global declaration
/usr/include/string.h:303: error: shadowed declaration is here
.../bfd/wasm-module.c: In function 'wasm_compute_custom_section_file_position':
.../bfd/wasm-module.c:523: error: declaration of 'index' shadows a global declaration
/usr/include/string.h:303: error: shadowed declaration is here
and:
cc1: warnings being treated as errors
.../opcodes/wasm32-dis.c: In function 'print_insn_wasm32':
.../opcodes/wasm32-dis.c:272: error: declaration of 'index' shadows a global declaration
/usr/include/string.h:303: error: shadowed declaration is here
make[4]: *** [wasm32-dis.lo] Error 1
which for versions of GCC before 4.8 prevent support for the WebAssembly
target from being built. See also GCC PR c/53066.
bfd/
* wasm-module.c (wasm_scan_name_function_section): Rename
`index' local variable to `idx'.
opcodes/
* wasm32-dis.c (print_insn_wasm32): Rename `index' local
variable to `function_index'.
This fixes the case where all of a group is removed with ld -r, the
situation in the PR, and failures where part of a group is removed
that contain relocs.
bfd/
PR 22836
* elf.c (_bfd_elf_fixup_group_sections): Account for removed
relocation sections. If size reduces to just the flag word,
remove that too and mark with SEC_EXCLUDE.
* elflink.c (bfd_elf_final_link): Strip empty group sections.
binutils/
* testsuite/binutils-all/group-7.s,
* testsuite/binutils-all/group-7a.d,
* testsuite/binutils-all/group-7b.d,
* testsuite/binutils-all/group-7c.d: New tests.
* testsuite/binutils-all/objcopy.exp: Run them.
ld/
* testsuite/ld-elf/pr22836-2.d,
* testsuite/ld-elf/pr22836-2.s: New test.
lld lays out the relro segment differently to GNU ld, not bothering to
include the first few bytes of .got.plt and padding out to a page at
the end of the segment. This patch teaches binutils to recognize the
different (and somewhat inferior) layout as valid.
bfd/
PR 22829
* elf.c (assign_file_positions_for_non_load_sections): Rewrite
PT_GNU_RELRO setup.
ld/
* testsuite/ld-x86-64/pr14207.d: Adjust relro p_filesz.
See email thread starting here: https://www.sourceware.org/ml/binutils/2018-01/msg00001.html
include * coff/msdos.h: New header.
* coff/pe.h: Move common defines to msdos.h.
* coff/powerpc.h: Likewise.
bfd * i386msdos.c (msdos_mkobject); New function.
(msdos_object_p): New function.
(i386_msdos_vec): Use msdos_object_p as the check_format
function.
* peicode.h: Rename external_PEI_DOS_hdr, DOSMAGIC, and
NT_SIGNATURE to external_DOS_hdr, IMAGE_DOS_SIGNATURE, and
IMAGE_NT_SIGNATURE.
* peXXigen.c: Likewise.
* coff-ia64.c: Likewise.
There are 2 failures left in the linker testsuite on SPARC64/Linux and
they are caused by 2 different issues leading to the same end effect:
the overflow of the relocation section for the GOT, i.e. the linker
generates too many dynamic relocations for the GOT wrt the size of the
relocation section, leading to memory corruption and missing relocations
in the final binary.
The first issue was introduced by:
https://sourceware.org/ml/binutils/2017-06/msg00368.html
which makes the linker generate more R_SPARC_RELATIVE relocations for
the GOT without adjusting the size of the relocation section. This is
fixed by (1) preventively adjusting this size in allocate_dynrelocs and
(2) generating R_SPARC_NONE if needed when R_SPARC_GOTDATA_OP is relaxed.
The second issue is that we generate a GOT relocation for an undefined
weak symbol with non-default visibility in a PIC binary without accounting
for that in the size of the relocation section. Since the address of the
symbol should resolve to 0 at run time, it is fixed by not generating the
relocation at all, i.e. leaving the GOT entry zeroed.
bfd/
* elfxx-sparc.c (UNDEFINED_WEAK_RESOLVED_TO_ZERO): Reorder conditions.
(sparc_elf_append_rela): Assert that there is enough room in section.
(_bfd_sparc_elf_copy_indirect_symbol): Fix formatting.
(_bfd_sparc_elf_adjust_dynamic_symbol): Minor tweak.
(allocate_dynrelocs): Remove outdated comments and reorder conditions.
For a symbol subject to a GOT relocation, reserve a slot in the
relocation section if the symbol isn't dynamic and we are in PIC mode.
(_bfd_sparc_elf_relocate_section) <R_SPARC_GOTDATA_OP>: If relocation
is relaxed and a slot was reserved, generate a R_SPARC_NONE relocation.
<R_SPARC_GOTDATA_OP_HIX22>: Adjust comments.
<R_SPARC_PC10>: Reorder conditions. Remove always-false assertion.
(_bfd_sparc_elf_finish_dynamic_symbol): Rename local_undefweak into
resolved_to_zero. Do not generate a dynamic GOT relocation for an
undefined weak symbol with non-default visibility. Remove superfluous
'else' and fix formatting.
Solaris requires to keep _GLOBAL_OFFSET_TABLE_ even if it isn't used.
This patch detects Solaris target and keeps _GLOBAL_OFFSET_TABLE_ for
Solaris.
* elf32-i386.c (elf32_i386_copy_solaris_special_section_fields):
New prototype.
(elf_i386_link_setup_gnu_properties): Set need_global_offset_table
for Solaris.
* elf64-x86-64.c (elf64_x86_64_copy_solaris_special_section_fields):
New prototype.
(elf_x86_64_link_setup_gnu_properties): Set
need_global_offset_table for Solaris.
* elfxx-x86.c (_bfd_x86_elf_size_dynamic_sections): Keep the
unused _GLOBAL_OFFSET_TABLE_ for Solaris.
(_bfd_x86_elf_link_setup_gnu_properties): Copy
need_global_offset_table.
* elfxx-x86.h (elf_x86_link_hash_table): Add
need_global_offset_table.
(elf_x86_init_table): Likewise.
This reverts most of commit 1be5d8d3bb.
Left in place are addition of --no-plt-align to some ppc32 ld tests
and the ld.texinfo --no-plt-thread-safe fix.
This is -fpie -pie generating dynamic relocations in the text section,
simply because no TLS transitions are applied in PIE mode. The meat
of the patch is to turn calls to bfd_link_pic (info) in TLS-related code
into !bfd_link_executable (info) and there are quite a lot of them...
bfd/
* elfxx-sparc.c (sparc_elf_tls_transition): Turn call to bfd_link_pic
into call to !bfd_link_executable and tidy up.
(_bfd_sparc_elf_check_relocs): Fix formatting and tidy up.
<R_SPARC_TLS_LE_HIX22>: Turn call to bfd_link_pic into call to
!bfd_link_executable.
<R_SPARC_TLS_IE_HI22>: Likewise.
<GOT relocations>: Remove useless code, tidy and merge blocks.
<R_SPARC_TLS_GD_CALL>: Turn call to bfd_link_pic into call to
!bfd_link_executable.
<R_SPARC_WPLT30>: Tidy up.
(_bfd_sparc_elf_gc_mark_hook): Turn call to bfd_link_pic into call
to !bfd_link_executable.
(allocate_dynrelocs): Likewise.
(_bfd_sparc_elf_relocate_section): Fix formatting and tidy up.
<R_SPARC_TLS_GD_HI22>: Merge into...
<R_SPARC_TLS_GD_LO10>: ...this. Adjust 4th argument in call to
sparc_elf_tls_transition and remove redundant code.
<R_SPARC_TLS_LDM_HI22>: Turn call to bfd_link_pic into call to
!bfd_link_executable.
<R_SPARC_TLS_LDO_HIX22>: Likewise.
<R_SPARC_TLS_LE_HIX22>: Likewise. Tidy up.
<R_SPARC_TLS_LDM_CALL>: Likewise.
<R_SPARC_TLS_GD_CALL>: Likewise. Tidy up.
<R_SPARC_TLS_GD_ADD>: Likewise.
<R_SPARC_TLS_LDM_ADD>: Likewise.
<R_SPARC_TLS_LDO_ADD>: Likewise.
<R_SPARC_TLS_IE_LD>: Likewise.
ld/
* testsuite/ld-elf/tls.exp (AFLAGS_PIC): Define on SPARC.
(pr22263-1): Pass AFLAGS_PIC to the assembler.
* testsuite/ld-sparc/tlspie32.s: Add test for other 3 transitions.
* testsuite/ld-sparc/tlspie32.dd: Adjust to above.
* testsuite/ld-sparc/tlspie64.s: Add test for other 3 transitions.
* testsuite/ld-sparc/tlspie64.dd: Adjust to above.
PR 22789
* elfxx-mips.c (_bfd_mips_elf_find_nearest_line): If the dwarf
functions failed to find the function name, try the generic elf
find function instead.
GCC 8 will bring a new warning option which will detect possible
overflow and truncation on string manipulation functions. For more
details, see:
https://gcc.gnu.org/ml/gcc-patches/2017-08/msg00471.html
While compiling BFD with it, I can see one place on bfd/coff-rs6000.c
where the warning is triggered. This:
(void) strncpy (fhdr.magic, XCOFFARMAG, SXCOFFARMAG);
will not include the trailing NUL on fhdr.magic, but that's fine
because it's a magic number. The fix is trivial: just use memcpy
instead.
OK to push?
2018-02-06 Sergio Durigan Junior <sergiodj@redhat.com>
* coff-rs6000.c (xcoff_write_archive_contents_old): Use
'memcpy' instead of 'strncpy' when writing the magic number.
PR 22794
* opncls.c (bfd_get_debug_link_info_1): Check the size of the
section before attempting to read it in.
(bfd_get_alt_debug_link_info): Likewise.
The nm utility supports -l for using debug information to obtain file and line information for each symbol, if available.
We have a tool that consumes this information and displays it.
This identified a problem with the 'nm' utility.
When a source is compiled with -O2, functions can be inlined. The compiler also produces an uninlined copy of the function, normally for linking to other object files.
In the case of DWARF2 debug information, the compiler generates debug information to describe a function. If that function is inlined, the compiler then references that debug information from the inlined and uninlined copies of the routine through the use of the DW_AT_abstract_origin reference.
When nm is used on such a file, it is not able to find file and line information because that information is present in the common debug information and not at each actual implementation of the function.
The 'nm' utility only retrieves the name of the function from the abstract origin debug information and no more.
What I am proposing is to modify the find_abstract_instance_name() function (which I renamed to find_abstract_instance() ) to return the name of the function as well as any file and line information. The routine is already parsing all of the debug information in the abstract instance, so it is easy to pick up the file and line information at that time. If, for some reason, the file and line information is not present, the routine behaves as before.
For example, if I have a simple test case:
int foo(int j)
{
if (j < 15)
j += j << 2;
else
j += j << 6;
return j;
}
int main (int argc,char **argv)
{
int i = argc;
i += foo(i);
return i;
}
If that test case is compiled with -O2 and then 'nm -l' reads that executable, it currently produces this symbol output (ignoring a lot of library symbols):
8048400 T foo
080482e0 T main /scratch/pcarroll/its254/test/mytest.c:12
If I modify 'nm' to return file and line information for abstract instances, it produces the following output:
08048400 T foo /scratch/pcarroll/its254/test/mytest.c:1
080482e0 T main /scratch/pcarroll/its254/test/mytest.c:12
--------------------------------------------------------------------------
bfd * bfd/dwarf2.c (find_abstract_name): Modified to return file and
line information in addition to name, if they can be found.
Alan Modra
GDB Administrator
Jim Wilson
Eric Botcazou
Nick Clifton
H.J. Lu
Sergei Trofimovich
Maciej W. Rozycki
Zebediah Figura
Sergio Durigan Junior
Paul Carroll