X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gas%2Fehopt.c;h=1e2e5f880d87b039e8b19e3c385e91222fe041a6;hb=d835a58baae720abe909795cb68763040d1750a8;hp=6e19ae69bf1647eb55efbf8a6cbb7724a488d445;hpb=e5f08f7e33b2a398b2bdc07c970478693c265753;p=deliverable%2Fbinutils-gdb.git diff --git a/gas/ehopt.c b/gas/ehopt.c index 6e19ae69bf..1e2e5f880d 100644 --- a/gas/ehopt.c +++ b/gas/ehopt.c @@ -1,23 +1,23 @@ /* ehopt.c--optimize gcc exception frame information. - Copyright 1998, 2000, 2001, 2003 Free Software Foundation, Inc. + Copyright (C) 1998-2020 Free Software Foundation, Inc. Written by Ian Lance Taylor . -This file is part of GAS, the GNU Assembler. + This file is part of GAS, the GNU Assembler. -GAS 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 2, or (at your option) -any later version. + GAS 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. -GAS 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. + GAS 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. -You should have received a copy of the GNU General Public License -along with GAS; see the file COPYING. If not, write to the Free -Software Foundation, 59 Temple Place - Suite 330, Boston, MA -02111-1307, USA. */ + You should have received a copy of the GNU General Public License + along with GAS; see the file COPYING. If not, write to the Free + Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA + 02110-1301, USA. */ #include "as.h" #include "subsegs.h" @@ -26,7 +26,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA ELF, since the exception frame information is always in a format derived from DWARF. */ -#include "elf/dwarf2.h" +#include "dwarf2.h" /* Try to optimize gcc 2.8 exception frame information. @@ -94,17 +94,16 @@ struct cie_info int z_augmentation; }; -static int get_cie_info PARAMS ((struct cie_info *)); +static int get_cie_info (struct cie_info *); /* Extract information from the CIE. */ static int -get_cie_info (info) - struct cie_info *info; +get_cie_info (struct cie_info *info) { fragS *f; fixS *fix; - int offset; + unsigned int offset; char CIE_id; char augmentation[10]; int iaug; @@ -112,22 +111,14 @@ get_cie_info (info) /* We should find the CIE at the start of the section. */ -#if defined (BFD_ASSEMBLER) || defined (MANY_SEGMENTS) f = seg_info (now_seg)->frchainP->frch_root; -#else - f = frchain_now->frch_root; -#endif -#ifdef BFD_ASSEMBLER fix = seg_info (now_seg)->frchainP->fix_root; -#else - fix = *seg_fix_rootP; -#endif /* Look through the frags of the section to find the code alignment. */ /* First make sure that the CIE Identifier Tag is 0/-1. */ - if (strcmp (segment_name (now_seg), ".debug_frame") == 0) + if (strncmp (segment_name (now_seg), ".debug_frame", 12) == 0) CIE_id = (char)0xff; else CIE_id = 0; @@ -234,6 +225,19 @@ get_cie_info (info) return 1; } +enum frame_state +{ + state_idle, + state_saw_size, + state_saw_cie_offset, + state_saw_pc_begin, + state_seeing_aug_size, + state_skipping_aug, + state_wait_loc4, + state_saw_loc4, + state_error, +}; + /* This function is called from emit_expr. It looks for cases which we can optimize. @@ -248,24 +252,11 @@ get_cie_info (info) change *EXP and *PNBYTES. */ int -check_eh_frame (exp, pnbytes) - expressionS *exp; - unsigned int *pnbytes; +check_eh_frame (expressionS *exp, unsigned int *pnbytes) { struct frame_data { - enum frame_state - { - state_idle, - state_saw_size, - state_saw_cie_offset, - state_saw_pc_begin, - state_seeing_aug_size, - state_skipping_aug, - state_wait_loc4, - state_saw_loc4, - state_error, - } state; + enum frame_state state; int cie_info_ok; struct cie_info cie_info; @@ -286,10 +277,16 @@ check_eh_frame (exp, pnbytes) if (flag_traditional_format) return 0; +#ifdef md_allow_eh_opt + if (! md_allow_eh_opt) + return 0; +#endif + /* Select the proper section data. */ - if (strcmp (segment_name (now_seg), ".eh_frame") == 0) + if (strncmp (segment_name (now_seg), ".eh_frame", 9) == 0 + && segment_name (now_seg)[9] != '_') d = &eh_frame_data; - else if (strcmp (segment_name (now_seg), ".debug_frame") == 0) + else if (strncmp (segment_name (now_seg), ".debug_frame", 12) == 0) d = &debug_frame_data; else return 0; @@ -328,7 +325,7 @@ check_eh_frame (exp, pnbytes) case state_saw_size: case state_saw_cie_offset: /* Assume whatever form it appears in, it appears atomically. */ - d->state += 1; + d->state = (enum frame_state) (d->state + 1); break; case state_saw_pc_begin: @@ -404,13 +401,10 @@ check_eh_frame (exp, pnbytes) subtracted were in the same frag and the expression was reduced to a constant. We can do the optimization entirely in this function. */ - if (d->cie_info.code_alignment > 0 - && exp->X_add_number % d->cie_info.code_alignment == 0 - && exp->X_add_number / d->cie_info.code_alignment < 0x40) + if (exp->X_add_number < 0x40) { d->loc4_frag->fr_literal[d->loc4_fix] - = DW_CFA_advance_loc - | (exp->X_add_number / d->cie_info.code_alignment); + = DW_CFA_advance_loc | exp->X_add_number; /* No more bytes needed. */ return 1; } @@ -425,23 +419,44 @@ check_eh_frame (exp, pnbytes) *pnbytes = 2; } } - else if (exp->X_op == O_subtract) + else if (exp->X_op == O_subtract && d->cie_info.code_alignment == 1) { /* This is a case we can optimize. The expression was not reduced, so we can not finish the optimization until the end of the assembly. We set up a variant frag which we handle later. */ - int fr_subtype; - - if (d->cie_info.code_alignment > 0) - fr_subtype = d->cie_info.code_alignment << 3; - else - fr_subtype = 0; - - frag_var (rs_cfa, 4, 0, fr_subtype, make_expr_symbol (exp), + frag_var (rs_cfa, 4, 0, 1 << 3, make_expr_symbol (exp), d->loc4_fix, (char *) d->loc4_frag); return 1; } + else if ((exp->X_op == O_divide + || exp->X_op == O_right_shift) + && d->cie_info.code_alignment > 1) + { + if (symbol_symbolS (exp->X_add_symbol) + && symbol_constant_p (exp->X_op_symbol) + && S_GET_SEGMENT (exp->X_op_symbol) == absolute_section + && ((exp->X_op == O_divide + ? *symbol_X_add_number (exp->X_op_symbol) + : (offsetT) 1 << *symbol_X_add_number (exp->X_op_symbol)) + == (offsetT) d->cie_info.code_alignment)) + { + expressionS *symval; + + symval = symbol_get_value_expression (exp->X_add_symbol); + if (symval->X_op == O_subtract) + { + /* This is a case we can optimize as well. The + expression was not reduced, so we can not finish + the optimization until the end of the assembly. + We set up a variant frag which we handle later. */ + frag_var (rs_cfa, 4, 0, d->cie_info.code_alignment << 3, + make_expr_symbol (symval), + d->loc4_fix, (char *) d->loc4_frag); + return 1; + } + } + } break; case state_error: @@ -457,8 +472,7 @@ check_eh_frame (exp, pnbytes) relaxation loop. We set fr_subtype{0:2} to the expected length. */ int -eh_frame_estimate_size_before_relax (frag) - fragS *frag; +eh_frame_estimate_size_before_relax (fragS *frag) { offsetT diff; int ca = frag->fr_subtype >> 3; @@ -466,7 +480,11 @@ eh_frame_estimate_size_before_relax (frag) diff = resolve_symbol_value (frag->fr_symbol); - if (ca > 0 && diff % ca == 0 && diff / ca < 0x40) + gas_assert (ca > 0); + diff /= ca; + if (diff == 0) + ret = -1; + else if (diff < 0x40) ret = 0; else if (diff < 0x100) ret = 1; @@ -475,7 +493,7 @@ eh_frame_estimate_size_before_relax (frag) else ret = 4; - frag->fr_subtype = (frag->fr_subtype & ~7) | ret; + frag->fr_subtype = (frag->fr_subtype & ~7) | (ret & 7); return ret; } @@ -485,12 +503,13 @@ eh_frame_estimate_size_before_relax (frag) the frag. This returns the change in frag length. */ int -eh_frame_relax_frag (frag) - fragS *frag; +eh_frame_relax_frag (fragS *frag) { int oldsize, newsize; oldsize = frag->fr_subtype & 7; + if (oldsize == 7) + oldsize = -1; newsize = eh_frame_estimate_size_before_relax (frag); return newsize - oldsize; } @@ -500,43 +519,50 @@ eh_frame_relax_frag (frag) fr_subtype{0:2} will be the desired length of the frag. */ void -eh_frame_convert_frag (frag) - fragS *frag; +eh_frame_convert_frag (fragS *frag) { offsetT diff; fragS *loc4_frag; - int loc4_fix; + int loc4_fix, ca; loc4_frag = (fragS *) frag->fr_opcode; loc4_fix = (int) frag->fr_offset; diff = resolve_symbol_value (frag->fr_symbol); + ca = frag->fr_subtype >> 3; + gas_assert (ca > 0); + diff /= ca; switch (frag->fr_subtype & 7) { case 0: - { - int ca = frag->fr_subtype >> 3; - assert (ca > 0 && diff % ca == 0 && diff / ca < 0x40); - loc4_frag->fr_literal[loc4_fix] = DW_CFA_advance_loc | (diff / ca); - } + gas_assert (diff < 0x40); + loc4_frag->fr_literal[loc4_fix] = DW_CFA_advance_loc | diff; break; case 1: - assert (diff < 0x100); + gas_assert (diff < 0x100); loc4_frag->fr_literal[loc4_fix] = DW_CFA_advance_loc1; frag->fr_literal[frag->fr_fix] = diff; break; case 2: - assert (diff < 0x10000); + gas_assert (diff < 0x10000); loc4_frag->fr_literal[loc4_fix] = DW_CFA_advance_loc2; md_number_to_chars (frag->fr_literal + frag->fr_fix, diff, 2); break; - default: + case 4: md_number_to_chars (frag->fr_literal + frag->fr_fix, diff, 4); break; + + case 7: + gas_assert (diff == 0); + frag->fr_fix -= 8; + break; + + default: + abort (); } frag->fr_fix += frag->fr_subtype & 7;