From: Alan Modra <amodra@gmail.com>
Date: Wed, 17 Apr 2024 08:46:55 +0000 (+0930)
Subject: Tidy objdump opb expressions
X-Git-Tag: gdb-15-branchpoint~358
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=170957ff9b847cf44f6121fd846f5483f2090afd;p=thirdparty%2Fbinutils-gdb.git

Tidy objdump opb expressions

I don't think any of these can overflow, but since all of the
expressions I'm editing here are inside a while loop with condition
addr_offset < stop_offset, this change makes it more obvious that they
can't overflow.

	* objdump.c (disassemble_bytes): Calculate octet expressions
	involving both addr_offset and stop_offset by first
	subtracting addr_offset from stop_offset.
---

diff --git a/binutils/objdump.c b/binutils/objdump.c
index 6396174d50f..f92e14b33e4 100644
--- a/binutils/objdump.c
+++ b/binutils/objdump.c
@@ -3356,28 +3356,28 @@ disassemble_bytes (struct disassemble_info *inf,
       /* If we see more than SKIP_ZEROES octets of zeroes, we just
 	 print `...'.  */
       if (! disassemble_zeroes)
-	for (; addr_offset * opb + octets < stop_offset * opb; octets++)
+	for (; octets < (stop_offset - addr_offset) * opb; octets++)
 	  if (data[addr_offset * opb + octets] != 0)
 	    break;
       if (! disassemble_zeroes
 	  && (inf->insn_info_valid == 0
 	      || inf->branch_delay_insns == 0)
 	  && (octets >= skip_zeroes
-	      || (addr_offset * opb + octets == stop_offset * opb
+	      || (octets == (stop_offset - addr_offset) * opb
 		  && octets < skip_zeroes_at_end)))
 	{
 	  /* If there are more nonzero octets to follow, we only skip
 	     zeroes in multiples of 4, to try to avoid running over
 	     the start of an instruction which happens to start with
 	     zero.  */
-	  if (addr_offset * opb + octets != stop_offset * opb)
+	  if (octets != (stop_offset - addr_offset) * opb)
 	    octets &= ~3;
 
 	  /* If we are going to display more data, and we are displaying
 	     file offsets, then tell the user how many zeroes we skip
 	     and the file offset from where we resume dumping.  */
 	  if (display_file_offsets
-	      && addr_offset + octets / opb < stop_offset)
+	      && octets / opb < stop_offset - addr_offset)
 	    printf (_("\t... (skipping %lu zeroes, "
 		      "resuming at file offset: 0x%lx)\n"),
 		    (unsigned long) (octets / opb),
@@ -3529,7 +3529,7 @@ disassemble_bytes (struct disassemble_info *inf,
 	      bfd_vma j;
 
 	      octets = octets_per_line;
-	      if (addr_offset + octets / opb > stop_offset)
+	      if (octets / opb > stop_offset - addr_offset)
 		octets = (stop_offset - addr_offset) * opb;
 
 	      for (j = addr_offset * opb; j < addr_offset * opb + octets; ++j)