45f764234a
Before this commit we didn't cleanly support CFI directives because the internal offsets used to get relaxed which broke them. This patch significantly reworks how we handle linker relaxations: * DWARF is now properly supported * There is a ".option norelax" to disable relaxations, for when users write assembly that can't be relaxed (if it's to be later patched up, for example). * There is an additional _RELAX relocation that specifies when previous relocations can be relaxed. We're in the process of documenting the RISC-V ELF ABI, which will include documentation of our relocations https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md but we expect that this relocation set will remain ABI compatible in the future (ie, it's safe to release). Thanks to Kuan-Lin Chen for figuring out how to correctly relax the debug info! include/ * elf/riscv.h: Add R_RISCV_TPREL_I through R_RISCV_SET32. bfd/ * reloc.c (BFD_RELOC_RISCV_TPREL_I): New relocation. (BFD_RELOC_RISCV_TPREL_S): Likewise. (BFD_RELOC_RISCV_RELAX): Likewise. (BFD_RELOC_RISCV_CFA): Likewise. (BFD_RELOC_RISCV_SUB6): Likewise. (BFD_RELOC_RISCV_SET8): Likewise. (BFD_RELOC_RISCV_SET8): Likewise. (BFD_RELOC_RISCV_SET16): Likewise. (BFD_RELOC_RISCV_SET32): Likewise. * elfnn-riscv.c (perform_relocation): Handle the new relocations. (_bfd_riscv_relax_tls_le): Likewise. (_bfd_riscv_relax_align): Likewise. (_bfd_riscv_relax_section): Likewise. (howto_table): Likewise. (riscv_reloc_map): Likewise. (relax_func_t): New type. (_bfd_riscv_relax_call): Add reserve_size argument, which controls the maximal offset pessimism. Correct type of max_alignment. (_bfd_riscv_relax_lui): Likewise. (_bfd_riscv_relax_tls_le): Likewise. (_bfd_riscv_relax_align): Likewise. (_bfd_riscv_relax_section): Compute the required reserve size when relocating and use it to when calling relax_func. * bfd-in2.h: Regenerate. * libbfd.h: Likewise. gas/ * config/tc-riscv.c (riscv_set_options): Add relax. (riscv_opts): Likewise. (s_riscv_option): Add relax and norelax. (riscv_apply_const_reloc): New function. (append_insn): Move constant relocation handling to riscv_apply_const_reloc. (md_pcrel_from): Likewise. (parse_relocation): Skip BFD_RELOC_UNUSED. (md_pcrel_from): Handle BFD_RELOC_RISCV_SUB6, BFD_RELOC_RISCV_RELAX, BFD_RELOC_RISCV_CFA. (md_apply_fix): Likewise. (riscv_pre_output_hook): New function. * config/tc-riscv.h (md_pre_output_hook): Define. (riscv_pre_output_hook): Declare. (DWARF_CIE_DATA_ALIGNMENT): Always -4.
106 lines
3.5 KiB
C
106 lines
3.5 KiB
C
/* tc-riscv.h -- header file for tc-riscv.c.
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Copyright 2011-2016 Free Software Foundation, Inc.
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Contributed by Andrew Waterman (andrew@sifive.com).
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Based on MIPS target.
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This file is part of GAS.
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GAS 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, or (at your option)
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any later version.
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GAS 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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You should have received a copy of the GNU General Public License
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along with this program; see the file COPYING3. If not,
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see <http://www.gnu.org/licenses/>. */
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#ifndef TC_RISCV
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#define TC_RISCV
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#include "opcode/riscv.h"
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struct frag;
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struct expressionS;
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#define TARGET_BYTES_BIG_ENDIAN 0
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#define TARGET_ARCH bfd_arch_riscv
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#define WORKING_DOT_WORD 1
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#define LOCAL_LABELS_FB 1
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/* Symbols named FAKE_LABEL_NAME are emitted when generating DWARF, so make
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sure FAKE_LABEL_NAME is printable. It still must be distinct from any
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real label name. So, append a space, which other labels can't contain. */
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#define FAKE_LABEL_NAME ".L0 "
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#define md_relax_frag(segment, fragp, stretch) \
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riscv_relax_frag (segment, fragp, stretch)
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extern int riscv_relax_frag (asection *, struct frag *, long);
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#define md_section_align(seg,size) (size)
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#define md_undefined_symbol(name) (0)
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#define md_operand(x)
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/* FIXME: it is unclear if this is used, or if it is even correct. */
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#define MAX_MEM_FOR_RS_ALIGN_CODE (1 + 2)
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/* The ISA of the target may change based on command-line arguments. */
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#define TARGET_FORMAT riscv_target_format()
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extern const char * riscv_target_format (void);
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#define md_after_parse_args() riscv_after_parse_args()
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extern void riscv_after_parse_args (void);
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#define md_parse_long_option(arg) riscv_parse_long_option (arg)
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extern int riscv_parse_long_option (const char *);
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#define md_pre_output_hook riscv_pre_output_hook()
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extern void riscv_pre_output_hook (void);
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/* Let the linker resolve all the relocs due to relaxation. */
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#define tc_fix_adjustable(fixp) 0
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#define md_allow_local_subtract(l,r,s) 0
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/* Values passed to md_apply_fix don't include symbol values. */
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#define MD_APPLY_SYM_VALUE(FIX) 0
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/* Global syms must not be resolved, to support ELF shared libraries. */
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#define EXTERN_FORCE_RELOC \
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(OUTPUT_FLAVOR == bfd_target_elf_flavour)
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/* Postpone text-section label subtraction calculation until linking, since
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linker relaxations might change the deltas. */
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#define TC_FORCE_RELOCATION_SUB_SAME(FIX, SEG) ((SEG)->flags & SEC_CODE)
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#define TC_FORCE_RELOCATION_SUB_LOCAL(FIX, SEG) 1
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#define TC_VALIDATE_FIX_SUB(FIX, SEG) 1
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#define TC_FORCE_RELOCATION_LOCAL(FIX) 1
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#define DIFF_EXPR_OK 1
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extern void riscv_pop_insert (void);
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#define md_pop_insert() riscv_pop_insert ()
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#define TARGET_USE_CFIPOP 1
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#define tc_cfi_frame_initial_instructions riscv_cfi_frame_initial_instructions
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extern void riscv_cfi_frame_initial_instructions (void);
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#define tc_regname_to_dw2regnum tc_riscv_regname_to_dw2regnum
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extern int tc_riscv_regname_to_dw2regnum (char *);
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extern unsigned xlen;
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#define DWARF2_DEFAULT_RETURN_COLUMN X_RA
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/* Even on RV64, use 4-byte alignment, as F registers may be only 32 bits. */
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#define DWARF2_CIE_DATA_ALIGNMENT -4
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#define elf_tc_final_processing riscv_elf_final_processing
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extern void riscv_elf_final_processing (void);
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#endif /* TC_RISCV */
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