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gcc/libgcc/config/nios2/elf-lib.h

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nios2: Support for GOT-relative DW_EH_PE_datarel encoding. 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.
2020-02-01 01:46:50 +01:00
/* Target macros for the Nios II port of GCC.
Update copyright years.
2022-01-03 10:42:10 +01:00
Copyright (C) 2015-2022 Free Software Foundation, Inc.
nios2: Support for GOT-relative DW_EH_PE_datarel encoding. 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.
2020-02-01 01:46:50 +01:00
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#define CRT_GET_RFIB_DATA(dbase) \
({ extern void *_gp_got; (dbase) = &_gp_got; })