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Re: [RFC] fix for avr_skip_prologue()


Hi,

Before I commit this, I wanted to know if this is the correct fix or just
an evil hack side-stepping the some other problem.

The problem shows up when I set a break point on a simple function as
such:

  (gdb) b foo_simple

If foo_simple() has no prologue, the break point is set at the _end_ of
the function (effectively the return insn).

If this fix is acceptable, is it too late to make it into the 5.2 branch?
I don't think your change is any worse than many other *_skip_prologue() tweaks. A typical skip_prologue() function is an accumulation of heuristics and a lot of comments.

2002-07-19  Theodore A. Roth  <troth@verinet.com>

	* gdb/avr-tdep.c(avr_skip_prologue): Fix to return the correct pc.

Index: gdb/avr-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/avr-tdep.c,v
retrieving revision 1.4
diff -u -p -r1.4 avr-tdep.c
--- gdb/avr-tdep.c	17 Jun 2002 23:32:27 -0000	1.4
+++ gdb/avr-tdep.c	19 Jul 2002 18:33:30 -0000
@@ -995,7 +995,12 @@ avr_skip_prologue (CORE_ADDR pc)
     {
       sal = find_pc_line (func_addr, 0);

-      if (sal.line != 0 && sal.end < func_end)
+      /* troth/2002-70-19: For some very simple functions, gcc doesn't
+         generate a prologue and the sal.end ends up being the insn (2 bytes)
+         before func_end (the address of the next func). By adjusting
+         func_end, we can catch these functions and return the correct pc. */
I'd just also mention that the instruction in question is ``return'' and is two bytes long.

+      if (sal.line != 0 && sal.end < (func_end-2))
 	return sal.end;
     }
enjoy,
Andrew





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