Fix h8300 relaxation.

3 files changed, 78 insertions, 32 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 8b096bc2947..479674b6c6b 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2002-11-15  Kazu Hirata  <kazu@cs.umass.edu>
+
+	* 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  <kdienes@apple.com>
 
 	* pef.c (bfd_pef_convert_architecture): Move declaration of
diff --git a/bfd/coff-h8300.c b/bfd/coff-h8300.c
index 4aab46bbb22..c83015e4efb 100644
--- a/bfd/coff-h8300.c
+++ b/bfd/coff-h8300.c
@@ -4,21 +4,21 @@
    Free Software Foundation, Inc.
    Written by Steve Chamberlain, <sac@cygnus.com>.
 
-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 1d643cbf0a9..9cb900b8b20 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)