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Date: Mon, 22 Sep 2008 13:13:00 -0000
From: Andrew Stubbs <ams@codesourcery.com>
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To: Mark Kettenis <mark.kettenis@xs4all.nl>, gdb@sourceware.org
Subject: Re: [commited] Detect bad debug info
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Daniel Jacobowitz wrote:
> On Mon, Sep 22, 2008 at 10:41:29AM +0100, Andrew Stubbs wrote:
>> The patch ensures that the debugger never attempts to read beyond the end 
>> of the register file.
> 
> Could you explain this in the code?  I think it's more enlightening
> than "bad debug info".

Very well, how about the attached?

Andrew

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2008-09-22  Andrew Stubbs  <ams@codesourcery.com>

	* frame.c (get_frame_register_bytes): Comment improvments.

Index: frame.c
===================================================================
RCS file: /cvs/src/src/gdb/frame.c,v
retrieving revision 1.252
diff -u -p -r1.252 frame.c
--- frame.c	19 Sep 2008 18:12:17 -0000	1.252
+++ frame.c	22 Sep 2008 13:12:09 -0000
@@ -806,13 +806,14 @@ get_frame_register_bytes (struct frame_i
       regnum++;
     }
 
-  /* Detect bad debug info.  */
+  /* Ensure that we will not read beyond the end of the register file.
+     This can only ever happen if the debug information is bad.  */
   maxsize = -offset;
   for (i = regnum; i < gdbarch_num_regs (gdbarch); i++)
     {
       int thissize = register_size (gdbarch, i);
       if (thissize == 0)
-	break;
+	break;	/* This register is not available on this architecture.  */
       maxsize += thissize;
     }
   if (len > maxsize)

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