2016-11-02 00:45:57 +08:00
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# This shell script emits a C file. -*- C -*-
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2021-01-01 06:58:58 +08:00
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# Copyright (C) 2004-2021 Free Software Foundation, Inc.
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2016-11-02 00:45:57 +08:00
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#
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# This file is part of the GNU Binutils.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
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# MA 02110-1301, USA.
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fragment <<EOF
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#include "ldmain.h"
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#include "ldctor.h"
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#include "elf/riscv.h"
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#include "elfxx-riscv.h"
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static void
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riscv_elf_before_allocation (void)
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{
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gld${EMULATION_NAME}_before_allocation ();
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if (link_info.discard == discard_sec_merge)
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link_info.discard = discard_l;
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2018-03-11 21:25:30 +08:00
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if (!bfd_link_relocatable (&link_info))
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{
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/* We always need at least some relaxation to handle code alignment. */
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if (RELAXATION_DISABLED_BY_USER)
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TARGET_ENABLE_RELAXATION;
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else
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ENABLE_RELAXATION;
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}
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2016-11-02 00:45:57 +08:00
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RISC-V: Relax PCREL to GPREL while doing other relaxations is dangerous.
I get the feedback recently that enable linker relaxations may fail to
build some program. Consider the following case,
.text
foo:
addi a0, a0, %pcrel_lo(.L2)
call foo
.L1: auipc a1, %pcrel_hi(data_g)
addi a1, a1, %pcrel_lo(.L1)
lui a2, %hi(data_g)
addi a2, a2, %lo(data_g)
lui a3, %tprel_hi(data_t)
add a3, a3, tp, %tprel_add(data_t)
addi a3, a3, %tprel_lo(data_t)
.L2: auipc a0, %pcrel_hi(data_g)
.data
.word 0x0
.global data_g
data_g: .word 0x1
.section .tbss
data_t: .word 0x0
The current ld reports `dangerous relocation error` when doing the
pcgp relaxation,
test.o: in function `foo':
(.text+0x0): dangerous relocation: %pcrel_lo missing matching %pcrel_hi
The .L2 auipc should not be removed since it is behind the corresponding
addi, so we record the information in the pcgp_relocs table to avoid
removing the auipc later. But current ld still remove it since we do not
update the pcgp_relocs table while doing other relaxations. I have two
solutions to fix the problem,
1. Update the pcgp_relocs table once we actually delete the code.
2. Add new relax pass to do the pcgp relaxations
At first I tried to do the first solution, and we need to update at
least three information - hi_sec_off of riscv_pcgp_lo_reloc, hi_sec_off
and hi_addr (symbol value) of riscv_pcgp_hi_reloc. Update the hi_sec_off
is simple, but it is more complicate to update the symbol value, since we
almost have to do parts the same works of _bfd_riscv_relax_call again in
the riscv_relax_delete_bytes to get the correct symbol value.
Compared with the first solution, the second one is more intuitive and
simple. We add a new relax pass to do the pcgp relaxations later, so
we will get all the information correctly in the _bfd_riscv_relax_call,
including the symbol value, without changing so much code. I do not see
any penalty by adding a new relax pass for now, so it should be fine
to delay the pcgp relaxations.
Besides, I have pass all riscv-gnu-toolchain regressions for this patch.
bfd/
* elfnn-riscv.c (_bfd_riscv_relax_section): Add a new relax pass
to do the pcgp relaxation later, after the lui and call relaxations,
but before the delete and alignment relaxations.
ld/
* emultempl/riscvelf.em (riscv_elf_before_allocation): Change
link_info.relax_pass from 3 to 4.
* testsuite/ld-riscv-elf/pcgp-relax.d: New testcase.
* testsuite/ld-riscv-elf/pcgp-relax.s: Likewise.
* testsuite/ld-riscv-elf/ld-riscv-elf.exp: Updated.
2020-11-18 11:39:52 +08:00
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link_info.relax_pass = 4;
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2016-11-02 00:45:57 +08:00
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}
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static void
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gld${EMULATION_NAME}_after_allocation (void)
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{
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int need_layout = 0;
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/* Don't attempt to discard unused .eh_frame sections until the final link,
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as we can't reliably tell if they're used until after relaxation. */
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if (!bfd_link_relocatable (&link_info))
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{
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need_layout = bfd_elf_discard_info (link_info.output_bfd, &link_info);
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if (need_layout < 0)
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{
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2017-10-11 12:18:45 +08:00
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einfo (_("%X%P: .eh_frame/.stab edit: %E\n"));
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2016-11-02 00:45:57 +08:00
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return;
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}
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}
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Move elf32.em and elf-generic.em functions
Many ELF linker targets support multiple "emulations" and thus have
multiple copies of elf32.em being compiled and linked into ld. This
patch moves much of elf32.em and elf-generic.em into files which will
be compiled just once, resulting in a 20% decrease in ld size for
--enable-targets=all.
* Makefile.am (ALL_EMUL_EXTRA_OFILES): Add ldelf and ldelfgen.
(CFILES, HFILES, EXTRA_ld_new_SOURCES): Likewise.
* configure.tgt: Formatting.
(targ_extra_ofiles): Init to ldelf.o ldelfgen.o, reset to just
ldelfgen.o for generic ELF targets, and empty for non-ELF.
* emultempl/aarch64elf.em (gldaarch64_layout_sections_again): Use
ldelf_map_segments.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, aarch64_for_each_input_file_wrapper),
(aarch64_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/alphaelf.em (alpha_after_parse): Use ldelf_map_segments.
* emultempl/armelf.em (gldarm_layout_sections_again): Likewise.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, arm_for_each_input_file_wrapper),
(arm_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/cr16elf.em (cr16elf_after_parse): Use ldelf_map_segments.
* emultempl/crxelf.em (crxelf_after_parse): Likewise. Delete
declaration.
* emultempl/cskyelf.em (gldcsky_layout_sections_again): Use
ldelf_map_segments.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, csky_for_each_input_file_wrapper),
(csky_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/genelf.em: Include ldelfgen.h.
(gld${EMULATION_NAME}_before_allocation): Use ldelf_map_segments.
* emultempl/hppaelf.em (hppaelf_after_parse): Likewise.
(hppaelf_layout_sections_again): Likewise.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, hppa_for_each_input_file_wrapper),
(hppa_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/ia64elf.em (ia64elf_after_parse): Use ldelf_map_segments.
* emultempl/m68hc1xelf.em (real_func),
(m68hc11_for_each_input_file_wrapper),
(m68hc11_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/metagelf.em (metagelf_layout_sections_again): Use
ldelf_map_segments.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, metag_for_each_input_file_wrapper),
(metag_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/mipself.em (real_func),
(mips_for_each_input_file_wrapper),
(mips_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/mmo.em: Don't include elf-bfd.h, do include ldelfgen.h.
(gld${EMULATION_NAME}_after_allocation): Use ldelf_map_segments.
* emultempl/nds32elf.em (nds32_elf_after_parse): Use ldelf_after_parse.
(nds32_elf_after_allocation): Comment fix.
* emultempl/nios2elf.em (nios2elf_layout_sections_again): Use
ldelf_map_segments.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, nios2_for_each_input_file_wrapper),
(nios2_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
* emultempl/ppc32elf.em (gld${EMULATION_NAME}_load_symbols): Delete
declaration.
(ppc_recognized_file): Call ldelf_load_symbols.
* emultempl/ppc64elf.em (ppc_layout_sections_again): Likewise.
(gld${EMULATION_NAME}_after_allocation): Likewise.
(real_func, ppc_for_each_input_file_wrapper),
(ppc_lang_for_each_input_file): Delete.
(lang_for_each_input_file): Don't define.
(gld${EMULATION_NAME}_load_symbols): Don't declare.
(ppc64_recognized_file): Call ldelf_load_symbols.
* emultempl/riscvelf.em (gld${EMULATION_NAME}_after_allocation):
Use ldelf_map_segments.
* emultempl/spuelf.em (spu_place_special_section): Use
ldelf_place_orphan.
* emultempl/tic6xdsbt.em (gld${EMULATION_NAME}_after_allocation):
Use ldelf_map_segments.
* emultempl/vms.em: Include ldelfgen.h.
(gld${EMULATION_NAME}_after_allocation): Use ldelf_map_segments.
* emultempl/elf32.em: Remove unnecessary headers, include ldelf.h
and ldelfgen.h. Move much of file content to..
* ldelf.c: ..here. New file.
* ldelf.h: New file.
* emultempl/elf-generic.em: Move gld${EMULATION_NAME}_map_segments..
* ldelfgen.c: ..to here.
* ldelfgen.h: New file.
* ldlang.c (lang_for_each_input_file): Adjust to only call func
on real files.
(lang_for_each_file): Likewise.
* po/SRC-POTFILES.in: Regenerate.
* Makefile.in: Regenerate.
2019-09-09 21:37:35 +08:00
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ldelf_map_segments (need_layout);
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2016-11-02 00:45:57 +08:00
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}
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2018-03-07 04:01:04 +08:00
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/* This is a convenient point to tell BFD about target specific flags.
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After the output has been created, but before inputs are read. */
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static void
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riscv_create_output_section_statements (void)
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{
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/* See PR 22920 for an example of why this is necessary. */
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if (strstr (bfd_get_target (link_info.output_bfd), "riscv") == NULL)
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{
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/* The RISC-V backend needs special fields in the output hash structure.
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These will only be created if the output format is a RISC-V format,
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hence we do not support linking and changing output formats at the
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same time. Use a link followed by objcopy to change output formats. */
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einfo (_("%F%P: error: cannot change output format"
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" whilst linking %s binaries\n"), "RISC-V");
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return;
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}
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}
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2016-11-02 00:45:57 +08:00
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EOF
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LDEMUL_BEFORE_ALLOCATION=riscv_elf_before_allocation
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LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
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2018-03-07 04:01:04 +08:00
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LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=riscv_create_output_section_statements
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