Re: [RFA/m32r] Fix m32r frame analyzer

["Kei Sakamoto" <sakamoto.kei@renesas.com>]

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> The save_read_memory will need to be in decode_prologue and applied to
> every memory read as a fetch of PC+/-4 could equally fail.  That means
> more interface changes to decode_prologue (return success/fail?).
> 
> On fail, it should also return the old PC and not zero - look at
> find_function_start_sal for why.
> 
> If you make those changes, you can commit.
> 
> Andrew

I revised my patch and committed it. Thank you.

Kei Sakamoto

2004-10-07  Kei Sakamoto  <sakamoto.kei@renesas.com>

        * m32r-tdep.c (decode_prologue): Support functions written
        in assembler language. Recognize trap instructions as the
        end of prologue.
        (m32r_frame_unwind_cache): Ditto.
        (m32r_skip_prologue): Extend search limit. Quit analyzing
        prologue if pc's location is not readable.

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Index: m32r-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/m32r-tdep.c,v
retrieving revision 1.32
diff -r1.32 m32r-tdep.c
3c3
<    Copyright 1996, 1998, 1999, 2000, 2001, 2002, 2003 Free Software
---
>    Copyright 1996, 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software
259c259
< static void
---
> static int
261c261
< 		 CORE_ADDR *pl_endptr)
---
> 		 CORE_ADDR *pl_endptr, unsigned long *framelength)
266d265
<   int maybe_one_more = 0;
267a267
>   CORE_ADDR after_push = 0;
269a270
>   LONGEST return_value;
275a277,280
>       /* Check if current pc's location is readable. */
>       if (!safe_read_memory_integer (current_pc, 2, &return_value))
> 	return -1;
> 
277a283,285
>       if (insn == 0x0000)
> 	break;
> 
282,293d289
< 	  /* Clear the parallel execution bit from 16 bit instruction */
< 	  if (maybe_one_more)
< 	    {
< 	      /* The last instruction was a branch, usually terminates
< 	         the series, but if this is a parallel instruction,
< 	         it may be a stack framing instruction */
< 	      if (!(insn & 0x8000))
< 		{
< 		  /* nope, we are really done */
< 		  break;
< 		}
< 	    }
299,300d294
< 	  if (maybe_one_more)
< 	    break;		/* This isnt the one more */
304a299
> 
305a301,305
> 
> 	      /* Check if current pc's location is readable. */
> 	      if (!safe_read_memory_integer (current_pc, 2, &return_value))
> 		return -1;
> 
314a315,316
> 		      && safe_read_memory_integer (current_pc + 2, 2,
> 						   &return_value)
327c329
< 	      after_prologue = current_pc;
---
> 	      after_push = current_pc + 2;
365a368
> 
371a375,380
>       /* End of prolog if any of these are trap instructions */
>       if ((insn & 0xfff0) == 0x10f0)
> 	{
> 	  after_prologue = current_pc;
> 	  break;
> 	}
376d384
< 	  maybe_one_more = 1;
386d393
< 	      maybe_one_more = 1;
391a399,401
>   if (framelength)
>     *framelength = framesize;
> 
402a413,419
> 	  else if (after_push != 0)
> 	    /* We did not find a "mv fp,sp", but we DID find
> 	       a push.  Is it safe to use that as the
> 	       end of the prologue?  I just don't know. */
> 	    {
> 	      *pl_endptr = after_push;
> 	    }
410c427
<       return;
---
>       return 0;
411a429
> 
416a435,436
> 
>   return 0;
422c442
< #define DEFAULT_SEARCH_LIMIT 44
---
> #define DEFAULT_SEARCH_LIMIT 128
428a449
>   LONGEST return_value;
450c471,479
<   decode_prologue (pc, func_end, &sal.end);
---
> 
>   /* If pc's location is not readable, just quit. */
>   if (!safe_read_memory_integer (pc, 4, &return_value))
>     return pc;
> 
>   /* Find the end of prologue.  */
>   if (decode_prologue (pc, func_end, &sal.end, NULL) < 0)
>     return pc;
> 
454d482
< 
483c511
<   CORE_ADDR pc;
---
>   CORE_ADDR pc, scan_limit;
486c514
<   unsigned long op;
---
>   unsigned long op, op2;
489a518
> 
499d527
< 
500a529,530
> 
>   scan_limit = frame_pc_unwind (next_frame);
502c532
<        pc > 0 && pc < frame_pc_unwind (next_frame); pc += 2)
---
>        pc > 0 && pc < scan_limit; pc += 2)
516,517c546,547
< 	      else if (((op >> 8) == 0xe4)	/* ld24 r4, xxxxxx; sub sp, r4 */
< 		       && get_frame_memory_unsigned (next_frame, pc + 4,
---
> 	      else if (((op >> 8) == 0xe4)
> 		       && get_frame_memory_unsigned (next_frame, pc + 2,
519a550
> 		  /* ld24 r4, xxxxxx; sub sp, r4 */
522c553
< 		  pc += 2;
---
> 		  pc += 2;	/* skip sub instruction */
524,525d554
< 	      else
< 		break;
527c556,558
< 	      pc += 2;
---
> 	      if (pc == scan_limit)
> 		scan_limit += 2;	/* extend the search */
> 	      pc += 2;		/* skip the immediate data */
551a583,588
> 	  break;		/* end of stack adjustments */
> 	}
>       else if ((op & 0xfff0) == 0x10f0)
> 	{
> 	  /* end of prologue if this is a trap instruction */
> 	  break;		/* end of stack adjustments */
553,557d589
<       else if (op == 0x7000)
< 	/* nop */
< 	continue;
<       else
< 	break;