The third parameter of find_fde_tail is an _Unwind_Ptr (which is an
integer type instead of a pointer), but we are passing NULL to it. This
causes a -Wint-conversion warning.
libgcc/
* unwind-dw2-fde-dip.c (_Unwind_Find_FDE): Call find_fde_tail
with 0 instead of NULL.
_dl_find_object returns success even if no unwind information has been
found, and dlfo_eh_frame is NULL.
libgcc/ChangeLog:
PR libgcc/104207
* unwind-dw2-fde-dip.c (_Unwind_Find_FDE): Add NULL check.
This allows switching to a different implementation for
PT_GNU_EH_FRAME lookup in a subsequent commit.
This moves some of the PT_GNU_EH_FRAME parsing out of the glibc loader
lock that is implied by dl_iterate_phdr. However, the FDE is already
parsed outside the lock before this change, so this does not introduce
additional crashes in case of a concurrent dlclose.
libgcc/ChangeLog:
* unwind-dw2-fde-dip.c (struct unw_eh_callback_data): Add hdr.
Remove func, ret.
(find_fde_tail): New function. Split from
_Unwind_IteratePhdrCallback. Move the result initialization
from _Unwind_Find_FDE.
(_Unwind_Find_FDE): Updated to call find_fde_tail.
Only bfin, frv, i386 and nios2 need this member at present.
libgcc/ChangeLog
* unwind-dw2-fde-dip.c (NEED_DBASE_MEMBER): Define.
(struct unw_eh_callback_data): Make dbase member conditional.
(unw_eh_callback_data_dbase): New function.
(base_from_cb_data): Simplify for the non-dbase case.
(_Unwind_IteratePhdrCallback): Adjust.
(_Unwind_Find_FDE): Likewise.
Disable USE_PT_GNU_EH_FRAME frame unwinder support for old OS versions,
fixing compilation errors:
.../libgcc/unwind-dw2-fde-dip.c:75:21: error: unknown type name 'Elf_Phdr'
75 | # define ElfW(type) Elf_##type
| ^~~~
.../libgcc/unwind-dw2-fde-dip.c:132:9: note: in expansion of macro 'ElfW'
132 | const ElfW(Phdr) *p_eh_frame_hdr;
| ^~~~
.../libgcc/unwind-dw2-fde-dip.c:75:21: error: unknown type name 'Elf_Phdr'
75 | # define ElfW(type) Elf_##type
| ^~~~
.../libgcc/unwind-dw2-fde-dip.c:133:9: note: in expansion of macro 'ElfW'
133 | const ElfW(Phdr) *p_dynamic;
| ^~~~
.../libgcc/unwind-dw2-fde-dip.c:165:37: warning: 'struct dl_phdr_info' declared inside parameter list will not be visible outside of this definition or declaration
165 | _Unwind_IteratePhdrCallback (struct dl_phdr_info *info, size_t size, void *ptr)
| ^~~~~~~~~~~~
[...]
and producing a working cross-compiler at least with VAX/NetBSD 1.6.2.
libgcc/
* unwind-dw2-fde-dip.c [__OpenBSD__ || __NetBSD__]
(USE_PT_GNU_EH_FRAME): Do not define if !TARGET_DL_ITERATE_PHDR.
On nios2-linux-gnu, there has been a long-standing bug in C++ exception
handling that sometimes resulted in link errors like
../nios2-linux-gnu/bin/ld: FDE encoding in /tmp/cccfpQ2l.o(.eh_frame) prevents .eh_frame_hdr table being created
when building some shared libraries or PIE executables. The root of
the problem is that GCC was incorrectly emitting an absolute encoding
in EH tables for PIC. This patch changes it to use either
DW_EH_PE_indirect (for global) or DW_EH_PE_datarel (for local), and
fixes libgcc so it can find the address of the GOT as the base address
for DW_EH_PE_datarel.
Complicating matters somewhat, GAS was missing support for
%gotoff(symbol) relocation syntax. I have just pushed a fix for that,
but I've added a configure check to test for presence of the binutils
support and fall back to the current absolute encoding (which works
most of the time) if it is not available. Once the fix makes it into
an official binutils release it might be appropriate to make this
error out instead.
Since this is a wrong-code bug and affects only nios2 target, I think
this is appropriate for Stage 4. I regression-tested on both
nios2-linux-gnu and nios2-elf, with and without the binutils support
present, before committing this.
2020-01-31 Sandra Loosemore <sandra@codesourcery.com>
gcc/
* configure.ac [nios2-*-*]: Check HAVE_AS_NIOS2_GOTOFF_RELOCATION.
* config.in: Regenerated.
* configure: Regenerated.
* config/nios2/nios2.h (ASM_PREFERRED_EH_DATA_FORMAT): Fix handling
for PIC when HAVE_AS_NIOS2_GOTOFF_RELOCATION.
(ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX): New.
gcc/testsuite/
* g++.target/nios2/hello-pie.C: New.
* g++.target/nios2/nios2.exp: New.
libgcc/
* config.host [nios2-*-linux*] (tmake_file, tm_file): Adjust.
* config/nios2-elf-lib.h: New.
* unwind-dw2-fde-dip.c (_Unwind_IteratePhdrCallback): Use existing
code for finding GOT base for nios2.
On behalf of szabolcs.nagy@arm.com
2015-04-22 Gregor Richards <gregor.richards@uwaterloo.ca>
Szabolcs Nagy <szabolcs.nagy@arm.com>
* unwind-dw2-fde-dip.c (USE_PT_GNU_EH_FRAME): Define it on
Linux if target provides dl_iterate_phdr.
Co-Authored-By: Szabolcs Nagy <szabolcs.nagy@arm.com>
From-SVN: r222328
