From 31eaabc5a9ae97a4dd57574b9c39d693fd7757cf Mon Sep 17 00:00:00 2001 From: Nick Clifton Date: Fri, 15 Nov 2002 11:18:47 +0000 Subject: [PATCH] Fix h8300 relaxation. --- bfd/ChangeLog | 6 ++++++ bfd/coff-h8300.c | 53 ++++++++++++++++++++++++++++++++++++++--------------- bfd/elf32-h8300.c | 51 ++++++++++++++++++++++++++++++++++----------------- 3 files changed, 78 insertions(+), 32 deletions(-) diff --git a/bfd/ChangeLog b/bfd/ChangeLog index 8b096bc294..479674b6c6 100644 --- a/bfd/ChangeLog +++ b/bfd/ChangeLog @@ -1,3 +1,9 @@ +2002-11-15 Kazu Hirata + + * coff-h8300.c (h8300_reloc16_estimate): Do not optimize away + jsr after a short jump. + * elf32-h8300.c (elf32_h8_relax_section): Likewise. + 2002-11-15 Klee Dienes * pef.c (bfd_pef_convert_architecture): Move declaration of diff --git a/bfd/coff-h8300.c b/bfd/coff-h8300.c index 4aab46bbb2..c83015e4ef 100644 --- a/bfd/coff-h8300.c +++ b/bfd/coff-h8300.c @@ -4,21 +4,21 @@ Free Software Foundation, Inc. Written by Steve Chamberlain, . -This file is part of BFD, the Binary File Descriptor library. + This file is part of BFD, the Binary File Descriptor library. -This program 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 of the License, or -(at your option) any later version. + This program 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 of the License, or + (at your option) any later version. -This program 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. + This program 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 this program; if not, write to the Free Software -Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "bfd.h" #include "sysdep.h" @@ -483,6 +483,13 @@ h8300_reloc16_estimate (abfd, input_section, reloc, shrink, link_info) closer if we do relax this branch. */ if ((int) gap >= -128 && (int) gap <= 128) { + bfd_byte code; + + if (!bfd_get_section_contents (abfd, input_section, & code, + reloc->address, 1)) + break; + code = bfd_get_8 (abfd, & code); + /* It's possible we may be able to eliminate this branch entirely; if the previous instruction is a branch around this instruction, and there's no label at this instruction, then we can reverse @@ -494,9 +501,25 @@ h8300_reloc16_estimate (abfd, input_section, reloc, shrink, link_info) lab1: lab1: This saves 4 bytes instead of two, and should be relatively - common. */ - - if (gap <= 126 + common. + + Only perform this optimisation for jumps (code 0x5a) not + subroutine calls, as otherwise it could transform: + + mov.w r0,r0 + beq .L1 + jsr @_bar + .L1: rts + _bar: rts + into: + mov.w r0,r0 + bne _bar + rts + _bar: rts + + which changes the call (jsr) into a branch (bne). */ + if (code == 0x5a + && gap <= 126 && last_reloc && last_reloc->howto->type == R_PCRBYTE) { diff --git a/bfd/elf32-h8300.c b/bfd/elf32-h8300.c index 1d643cbf0a..9cb900b8b2 100644 --- a/bfd/elf32-h8300.c +++ b/bfd/elf32-h8300.c @@ -2,21 +2,21 @@ Copyright 1993, 1995, 1998, 1999, 2001, 2002 Free Software Foundation, Inc. -This file is part of BFD, the Binary File Descriptor library. + This file is part of BFD, the Binary File Descriptor library. -This program 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 of the License, or -(at your option) any later version. + This program 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 of the License, or + (at your option) any later version. -This program 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. + This program 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 this program; if not, write to the Free Software -Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "bfd.h" #include "sysdep.h" @@ -827,14 +827,34 @@ elf32_h8_relax_section (abfd, sec, link_info, again) elf_section_data (sec)->this_hdr.contents = contents; symtab_hdr->contents = (unsigned char *) isymbuf; + /* Get the instruction code being relaxed. */ + code = bfd_get_8 (abfd, contents + irel->r_offset - 1); + /* If the previous instruction conditionally jumped around this instruction, we may be able to reverse the condition and redirect the previous instruction to the target of this instruction. Such sequences are used by the compiler to deal with - long conditional branches. */ - if ((int) gap <= 130 + long conditional branches. + + Only perform this optimisation for jumps (code 0x5a) not + subroutine calls, as otherwise it could transform: + + mov.w r0,r0 + beq .L1 + jsr @_bar + .L1: rts + _bar: rts + into: + mov.w r0,r0 + bne _bar + rts + _bar: rts + + which changes the call (jsr) into a branch (bne). */ + if (code == 0x5a + && (int) gap <= 130 && (int) gap >= -128 && last_reloc && ELF32_R_TYPE (last_reloc->r_info) == R_H8_PCREL8 @@ -890,9 +910,6 @@ elf32_h8_relax_section (abfd, sec, link_info, again) } } - /* We could not eliminate this jump, so just shorten it. */ - code = bfd_get_8 (abfd, contents + irel->r_offset - 1); - if (code == 0x5e) bfd_put_8 (abfd, 0x55, contents + irel->r_offset - 1); else if (code == 0x5a) -- 2.11.0