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5e5f37ed00
On x86, MAX_MEM_FOR_RS_ALIGN_CODE is 35, when the most common
alignment is 2**3 or 2**4, where the max memory required for the
alignment nops is 7 and 15 bytes respectively. So there is some
memory wasted since commit 83d94ae428. It's not a large amount,
especially considering that frag overhead on x86_46 is 144 bytes,
but even so I'd rather not be blamed for increasing gas memory usage.
So to reduce the memory we'd like to take the alignment into
consideration when initialising an rs_align_code frag. The only
difficulty here is start_bundle making an rs_align_code frag with an
alignment of zero initially, then later increasing the alignment. We
change that to use the bundle alignment when setting up the frag. I
think that is sufficient as bundle_align_p2 can't change in the middle
of a start_bundle/finish_bundle sequence.
I haven't modified any targets other than x86 in this patch. Most
won't benefit much due to using fairly small MAX_MEM_FOR_RS_ALIGN_CODE.
* read.c (start_bundle): Create rs_align_code frag with
bundle_align_p2 alignment, then set to zero alignment.
(finish_bundle): Adjust comment.
* frags.c (MAX_MEM_FOR_RS_ALIGN_CODE): Pass p2align and max
to macro.
* config/tc-i386.h (HANDLE_ALIGN): Assert that max_bytes is
sufficient for nop padding.
(max_mem_for_rs_align_code): New inline function.
(MAX_MEM_FOR_RS_ALIGN_CODE): Use it.
* config/tc-aarch64.h: Adjust MAX_MEM_FOR_RS_ALIGN_CODE.
* config/tc-alpha.h: Likewise.
* config/tc-arc.h: Likewise.
* config/tc-arm.h: Likewise.
* config/tc-epiphany.h: Likewise.
* config/tc-frv.h: Likewise.
* config/tc-ia64.h: Likewise.
* config/tc-kvx.h: Likewise.
* config/tc-loongarch.h: Likewise.
* config/tc-m32r.h: Likewise.
* config/tc-metag.h: Likewise.
* config/tc-mips.h: Likewise.
* config/tc-nds32.h: Likewise.
* config/tc-ppc.h: Likewise.
* config/tc-riscv.h: Likewise.
* config/tc-rl78.h: Likewise.
* config/tc-rx.h: Likewise.
* config/tc-score.h: Likewise.
* config/tc-sh.h: Likewise.
* config/tc-sparc.h: Likewise.
* config/tc-spu.h: Likewise.
* config/tc-tilegx.h: Likewise.
* config/tc-tilepro.h: Likewise.
* config/tc-visium.h: Likewise.
* config/tc-xtensa.h: Likewise.
125 lines
4.5 KiB
C
125 lines
4.5 KiB
C
/* tc-frv.h -- Header file for tc-frv.c.
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Copyright (C) 2002-2025 Free Software Foundation, Inc.
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This file is part of GAS, the GNU Assembler.
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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 GAS; see the file COPYING. If not, write to
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the Free Software Foundation, 51 Franklin Street - Fifth Floor,
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Boston, MA 02110-1301, USA. */
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#define TC_FRV
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#define LISTING_HEADER "FRV GAS "
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/* The target BFD architecture. */
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#define TARGET_ARCH bfd_arch_frv
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#define TARGET_FORMAT (frv_md_fdpic_enabled () \
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? "elf32-frvfdpic" : "elf32-frv")
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extern bool frv_md_fdpic_enabled (void);
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#define TARGET_BYTES_BIG_ENDIAN 1
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/* Permit temporary numeric labels. */
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#define LOCAL_LABELS_FB 1
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#define DIFF_EXPR_OK /* .-foo gets turned into PC relative relocs */
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/* We don't need to handle .word strangely. */
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#define WORKING_DOT_WORD
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/* Values passed to md_apply_fix don't include the symbol value. */
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#define MD_APPLY_SYM_VALUE(FIX) 0
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extern void frv_tomcat_workaround (void);
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#define md_cleanup frv_tomcat_workaround
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#define md_number_to_chars frv_md_number_to_chars
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extern void frv_md_number_to_chars (char *, valueT, int);
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extern long frv_relax_frag (fragS *, long);
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#define md_relax_frag(segment, fragP, stretch) frv_relax_frag(fragP, stretch)
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#define tc_fix_adjustable(FIX) frv_fix_adjustable (FIX)
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struct fix;
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extern bool frv_fix_adjustable (struct fix *);
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/* When relaxing, we need to emit various relocs we otherwise wouldn't. */
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#define TC_FORCE_RELOCATION(fix) frv_force_relocation (fix)
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extern int frv_force_relocation (struct fix *);
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/* If we simplify subtractions that aren't SUB_SAME or SUB_ABS, we end
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up with PCrel fixups, but since we don't have any PCrel relocs, we
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crash. Preventing simplification gets us a good, early error. */
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#define TC_FORCE_RELOCATION_SUB_LOCAL(FIX, SEG) 1
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#undef GAS_CGEN_MAX_FIXUPS
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#define GAS_CGEN_MAX_FIXUPS 1
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void frv_frob_label (symbolS *);
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#define tc_frob_label(sym) frv_frob_label(sym)
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#define tc_gen_reloc gas_cgen_tc_gen_reloc
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#define md_cgen_record_fixup_exp frv_cgen_record_fixup_exp
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/* Call md_pcrel_from_section(), not md_pcrel_from(). */
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#define MD_PCREL_FROM_SECTION(FIX, SEC) md_pcrel_from_section (FIX, SEC)
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/* After all of the symbols have been adjusted, go over the file looking
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for any relocations that pic won't support. */
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#define tc_frob_file() frv_frob_file ()
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extern void frv_frob_file (void);
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/* We don't want 0x00 for code alignment because this generates `add.p
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gr0, gr0, gr0' patterns. Although it's fine as a nop instruction,
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it has the VLIW packing bit set, which means if you have a bunch of
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them in a row and attempt to execute them, you'll exceed the VLIW
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capacity and fail. This also gets GDB confused sometimes, because
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it won't set breakpoints in instructions other than the first of a
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VLIW pack, so you used to be unable to set a breakpoint in the
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initial instruction of a function that followed such
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alignment-introduced instructions.
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We could have arranged to emit `nop' instructions (0x80880000),
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maybe even VLIW-pack sequences of nop instructions as much as
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possible for the selected machine type, just in case the alignment
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code actually happens to run, but this is probably too much effort
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for little gain. This code is not meant to be run anyway, so just
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emit nops. */
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#define MAX_MEM_FOR_RS_ALIGN_CODE(p2align, max) (3 + 4)
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#define HANDLE_ALIGN(SEC, FRAGP) do \
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if ((FRAGP)->fr_type == rs_align_code) \
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{ \
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valueT count = ((FRAGP)->fr_next->fr_address \
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- ((FRAGP)->fr_address + (FRAGP)->fr_fix)); \
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char *dest = (FRAGP)->fr_literal + (FRAGP)->fr_fix; \
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if ((count & 3) != 0) \
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{ \
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memset (dest, 0, (count & 3)); \
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(FRAGP)->fr_fix += (count & 3); \
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dest += (count & 3); \
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count -= (count & 3); \
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} \
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if (count) \
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{ \
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(FRAGP)->fr_var = 4; \
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*dest++ = 0x80; \
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*dest++ = 0x88; \
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*dest++ = 0x00; \
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*dest++ = 0x00; \
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} \
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} \
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while (0)
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