Re: RFA: ia64 tdep patch

["J. Johnston" <jjohnstn@redhat.com>]

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Kevin Buettner wrote:
> On Oct 17,  3:58pm, J. Johnston wrote:
> 
> 
>>The attached ia64 patch fixes a few problems, most notably
>>backtracing through signal handlers.
> 
> 
> I think these changes are mostly okay, but...
> 
> In your ChangeLog entry, you say:
> 
> 
>>	* ia64-tdep.c: Change all references of DEPRECATED_REGISTER_RAW_SIZE
>>	to use register_size() instead.
> 
> 
> Yet, later on, in the patch, I see that you're reintroducing a use of
> DEPRECATED_REGISTER_RAW_SIZE:
> 
>   +  else if (regnum == IA64_BR0_REGNUM)
>   +    {
>   +      CORE_ADDR br0 = 0;
>   +      CORE_ADDR addr = cache->saved_regs[IA64_BR0_REGNUM];
>   +      if (addr != 0)
>   +	{
>   +	  *lvalp = lval_memory;
>   +	  *addrp = addr;
>   +	  read_memory (addr, buf, DEPRECATED_REGISTER_RAW_SIZE (IA64_BR0_REGNUM));
>   +	  br0 = extract_unsigned_integer (buf, 8);
>   +	}
>   +      store_unsigned_integer (valuep, 8, br0);
>   +    }
> 
> Also, regarding:
> 
>        /* We want to calculate the previous bsp as the end of the previous register stack frame.
>  	 This corresponds to what the hardware bsp register will be if we pop the frame
>  	 back which is why we might have been called.  We know the beginning of the current
> -         frame is cache->bsp - cache->sof.  This value in the previous frame points to
> +	 frame is cache->bsp - cache->sof.  This value in the previous frame points to
>  	 the start of the output registers.  We can calculate the end of that frame by adding
>  	 the size of output (sof (size of frame) - sol (size of locals)).  */
>        ia64_frame_prev_register (next_frame, this_cache, IA64_CFM_REGNUM,
>  				&cfm_optim, &cfm_lval, &cfm_addr, &cfm_realnum, cfm_valuep);
>        prev_cfm = extract_unsigned_integer (cfm_valuep, 8);
> -
> +      
>        bsp = rse_address_add (cache->bsp, -(cache->sof));
>        prev_bsp = rse_address_add (bsp, (prev_cfm & 0x7f) - ((prev_cfm >> 7) & 0x7f));
> -
> +      
> 
> The first white space change is okay, but the latter two are not.  I'd
> really prefer to see whitespace changes occur via a separate patch anyway.
> 
> So, if you don't mind, could you please submit separate patches for:
> 
>   1) whitespace changes
>   2) DEPRECATED_... elimination
>   3) the CFM / backtracing changes.
> 
> Patches (1) and (2) are preapproved -- just make sure that you don't
> introduce extra white space on an otherwise blank line.  For (1) and
> (2), please post the patches that you end up committing.
> 
> Once (1) and (2) are split out, I'd like another chance to review what's
> left (patch 3).
> 

Ok, done.  A patch for 1) and 2) has been checked in.  See the new attached patch.

2003-10-20  Jeff Johnston  <jjohnstn@redhat.com>

	* ia64-tdep.c: (ia64_frame_cache): Add new prev_cfm field.
	(ia64_alloc_frame_cache):  Initialize new prev_cfm field to 0.
	(floatformat_valid): New static routine.
	(floatformat_ia64_ext): Add name field and set up is_valid routine
	to floatformat_valid().
	(examine_prologue):  For the previous cfm, use frame_unwind_register()
	if the cfm is not stored in a register-stack register.  Save the
	previous cfm value in the prev_cfm field.  Add debug output.
	(ia64_frame_this_id): Use frame_id_build_special() to also register
	the bsp.  Add debug output.
	(ia64_sigtramp_frame_this_id): Ditto.
	(ia64_frame_prev_register):  Look at cache saved_regs for a few more
	registers and also add some checks for framelessness before accepting
	current register values for fields such as return address.  For cfm,
	use the cached prev_cfm field if available.  Add debug output.
	(ia64_sigtramp_frame_init_saved_regs): Bump up base by 16 to get
	sp needed for calling lower level
	ia64_linux_sigcontext_register_address().  Also save the
	bsp and sp address as part of initialization.
	(ia64_sigtramp_frame_cache): Hard-code stack size as it can't be
	calculated.  Cache the bsp and cfm values.
	(ia64_sigtramp_frame_prev_register): Flesh this routine out instead of
	using ia64_frame_prev_register().  The saved values for bsp and sp can
	be taken from the cache.  Add debug output.
	(ia64_push_dummy_call): Use frame_id_build_special() to also register
	the bsp.


> With regard to (3), one of the questions that I already have concerns
> the following line in ia64_sigtramp_frame_init_saved_regs():
> 
> +      CORE_ADDR sp = cache->base + 16;
> 
> Could you explain what this is about?  (Preferably with a comment in the
> code?)
> 

I've simplified it.  It is the mem stack size that should have been added to the 
base.  I have added a comment that it cannot be calculated via prologue examination.

> Thanks,
> 
> Kevin
> 
> P.S. If you'd prefer to reverse things and submit patch 3 first, that'd
> be okay too.
> 

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Index: ia64-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/ia64-tdep.c,v
retrieving revision 1.99
diff -u -p -r1.99 ia64-tdep.c
--- ia64-tdep.c	20 Oct 2003 20:38:07 -0000	1.99
+++ ia64-tdep.c	20 Oct 2003 21:40:48 -0000
@@ -232,6 +232,7 @@ struct ia64_frame_cache
   CORE_ADDR saved_sp;	/* stack pointer for frame */
   CORE_ADDR bsp;	/* points at r32 for the current frame */
   CORE_ADDR cfm;	/* cfm value for current frame */
+  CORE_ADDR prev_cfm;   /* cfm value for previous frame */
   int   frameless;
   int   sof;		/* Size of frame  (decoded from cfm value) */
   int	sol;		/* Size of locals (decoded from cfm value) */
@@ -316,10 +317,18 @@ ia64_dwarf_reg_to_regnum (int reg)
   return reg;
 }
 
+static int
+floatformat_valid (fmt, from)
+     const struct floatformat *fmt;
+     const char *from;
+{
+  return 1;
+}
+
 const struct floatformat floatformat_ia64_ext =
 {
   floatformat_little, 82, 0, 1, 17, 65535, 0x1ffff, 18, 64,
-  floatformat_intbit_yes
+  floatformat_intbit_yes, "floatformat_ia64_ext", floatformat_valid
 };
 
 
@@ -1030,6 +1039,7 @@ ia64_alloc_frame_cache (void)
   cache->base = 0;
   cache->pc = 0;
   cache->cfm = 0;
+  cache->prev_cfm = 0;
   cache->sof = 0;
   cache->sol = 0;
   cache->sor = 0;
@@ -1450,9 +1460,20 @@ examine_prologue (CORE_ADDR pc, CORE_ADD
 
       /* For the previous argument registers we require the previous bof.  
 	 If we can't find the previous cfm, then we can do nothing.  */
+      cfm = 0;
       if (cache->saved_regs[IA64_CFM_REGNUM] != 0)
 	{
 	  cfm = read_memory_integer (cache->saved_regs[IA64_CFM_REGNUM], 8);
+	}
+      else if (cfm_reg != 0)
+	{
+	  frame_unwind_register (next_frame, cfm_reg, buf);
+	  cfm = extract_unsigned_integer (buf, 8);
+	}
+      cache->prev_cfm = cfm;
+      
+      if (cfm != 0)
+	{
 	  sor = ((cfm >> 14) & 0xf) * 8;
 	  sof = (cfm & 0x7f);
 	  sol = (cfm >> 7) & 0x7f;
@@ -1564,7 +1585,11 @@ ia64_frame_this_id (struct frame_info *n
   if (cache->base == 0)
     return;
 
-  (*this_id) = frame_id_build (cache->base, cache->pc);
+  (*this_id) = frame_id_build_special (cache->base, cache->pc, cache->bsp);
+  if (gdbarch_debug >= 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"regular frame id: code %lx, stack %lx, special %lx, next_frame %p\n",
+			this_id->code_addr, this_id->stack_addr, cache->bsp, next_frame);
 }
 
 static void
@@ -1628,18 +1653,20 @@ ia64_frame_prev_register (struct frame_i
     }
   else if (regnum == IA64_CFM_REGNUM)
     {
-      CORE_ADDR addr = 0;
-
-      if (cache->frameless)
+      CORE_ADDR addr = cache->saved_regs[IA64_CFM_REGNUM];
+      
+      if (addr != 0)
 	{
-	  CORE_ADDR cfm = 0;
-	  frame_unwind_register (next_frame, IA64_PFS_REGNUM, valuep);
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, valuep, register_size (current_gdbarch, regnum));
 	}
-      else
+      else if (cache->prev_cfm)
+	store_unsigned_integer (valuep, register_size (current_gdbarch, regnum), cache->prev_cfm);
+      else if (cache->frameless)
 	{
-	  addr = cache->saved_regs[IA64_CFM_REGNUM];
-	  if (addr != 0)
-	    read_memory (addr, valuep, register_size (current_gdbarch, regnum));
+	  CORE_ADDR cfm = 0;
+	  frame_unwind_register (next_frame, IA64_PFS_REGNUM, valuep);
 	}
     }
   else if (regnum == IA64_VFP_REGNUM)
@@ -1727,20 +1754,19 @@ ia64_frame_prev_register (struct frame_i
   else if (regnum == IA64_IP_REGNUM)
     {
       CORE_ADDR pc = 0;
+      CORE_ADDR addr = cache->saved_regs[IA64_VRAP_REGNUM];
 
-      if (cache->frameless)
+      if (addr != 0)
 	{
-	  frame_unwind_register (next_frame, IA64_BR0_REGNUM, buf);
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, buf, register_size (current_gdbarch, IA64_IP_REGNUM));
 	  pc = extract_unsigned_integer (buf, 8);
 	}
-      else
+      else if (cache->frameless)
 	{
-	  CORE_ADDR addr = cache->saved_regs[IA64_VRAP_REGNUM];
-	  if (addr != 0)
-	    {
-	      read_memory (addr, buf, register_size (current_gdbarch, IA64_IP_REGNUM));
-	      pc = extract_unsigned_integer (buf, 8);
-	    }
+	  frame_unwind_register (next_frame, IA64_BR0_REGNUM, buf);
+	  pc = extract_unsigned_integer (buf, 8);
 	}
       pc &= ~0xf;
       store_unsigned_integer (valuep, 8, pc);
@@ -1750,30 +1776,42 @@ ia64_frame_prev_register (struct frame_i
       ULONGEST slot_num = 0;
       CORE_ADDR pc= 0;
       CORE_ADDR psr = 0;
+      CORE_ADDR addr = cache->saved_regs[IA64_VRAP_REGNUM];
 
       frame_unwind_register (next_frame, IA64_PSR_REGNUM, buf);
       psr = extract_unsigned_integer (buf, 8);
 
-      if (cache->frameless)
+      if (addr != 0)
 	{
-	  CORE_ADDR pc;
-	  frame_unwind_register (next_frame, IA64_BR0_REGNUM, buf);
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, buf, register_size (current_gdbarch, IA64_IP_REGNUM));
 	  pc = extract_unsigned_integer (buf, 8);
 	}
-      else
+      else if (cache->frameless)
 	{
-	  CORE_ADDR addr = cache->saved_regs[IA64_VRAP_REGNUM];
-	  if (addr != 0)
-	    {
-	      read_memory (addr, buf, register_size (current_gdbarch, IA64_IP_REGNUM));
-	      pc = extract_unsigned_integer (buf, 8);
-	    }
+	  CORE_ADDR pc;
+	  frame_unwind_register (next_frame, IA64_BR0_REGNUM, buf);
+	  pc = extract_unsigned_integer (buf, 8);
 	}
       psr &= ~(3LL << 41);
       slot_num = pc & 0x3LL;
       psr |= (CORE_ADDR)slot_num << 41;
       store_unsigned_integer (valuep, 8, psr);
     }
+  else if (regnum == IA64_BR0_REGNUM)
+    {
+      CORE_ADDR br0 = 0;
+      CORE_ADDR addr = cache->saved_regs[IA64_BR0_REGNUM];
+      if (addr != 0)
+	{
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, buf, register_size (current_gdbarch, IA64_BR0_REGNUM));
+	  br0 = extract_unsigned_integer (buf, 8);
+	}
+      store_unsigned_integer (valuep, 8, br0);
+    }
  else if ((regnum >= IA64_GR32_REGNUM && regnum <= IA64_GR127_REGNUM) ||
 	   (regnum >= V32_REGNUM && regnum <= V127_REGNUM))
     {
@@ -1839,6 +1877,12 @@ ia64_frame_prev_register (struct frame_i
       else 
 	frame_unwind_register (next_frame, regnum, valuep);
     }
+
+  if (gdbarch_debug >= 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"regular prev register <%d> <%s> is %lx\n", regnum, 
+			(((unsigned) regnum <= IA64_NAT127_REGNUM)
+			 ? ia64_register_names[regnum] : "r??"), extract_unsigned_integer (valuep, 8));
 }
  
 static const struct frame_unwind ia64_frame_unwind =
@@ -1869,10 +1913,8 @@ ia64_sigtramp_frame_init_saved_regs (str
 	SIGCONTEXT_REGISTER_ADDRESS (cache->base, IA64_CFM_REGNUM);
       cache->saved_regs[IA64_PSR_REGNUM] = 
 	SIGCONTEXT_REGISTER_ADDRESS (cache->base, IA64_PSR_REGNUM);
-#if 0
       cache->saved_regs[IA64_BSP_REGNUM] = 
-	SIGCONTEXT_REGISTER_ADDRESS (frame->frame, IA64_BSP_REGNUM);
-#endif
+	SIGCONTEXT_REGISTER_ADDRESS (cache->base, IA64_BSP_REGNUM);
       cache->saved_regs[IA64_RNAT_REGNUM] = 
 	SIGCONTEXT_REGISTER_ADDRESS (cache->base, IA64_RNAT_REGNUM);
       cache->saved_regs[IA64_CCV_REGNUM] = 
@@ -1886,9 +1928,8 @@ ia64_sigtramp_frame_init_saved_regs (str
       cache->saved_regs[IA64_LC_REGNUM] = 
 	SIGCONTEXT_REGISTER_ADDRESS (cache->base, IA64_LC_REGNUM);
       for (regno = IA64_GR1_REGNUM; regno <= IA64_GR31_REGNUM; regno++)
-	if (regno != sp_regnum)
-	  cache->saved_regs[regno] =
-	    SIGCONTEXT_REGISTER_ADDRESS (cache->base, regno);
+	cache->saved_regs[regno] =
+	  SIGCONTEXT_REGISTER_ADDRESS (cache->base, regno);
       for (regno = IA64_BR0_REGNUM; regno <= IA64_BR7_REGNUM; regno++)
 	cache->saved_regs[regno] =
 	  SIGCONTEXT_REGISTER_ADDRESS (cache->base, regno);
@@ -1912,7 +1953,16 @@ ia64_sigtramp_frame_cache (struct frame_
   cache = ia64_alloc_frame_cache ();
 
   frame_unwind_register (next_frame, sp_regnum, buf);
-  cache->base = extract_unsigned_integer (buf, 8) + cache->mem_stack_frame_size;
+  /* Note that frame size is hard-coded below.  We cannot calculate it
+     via prologue examination.  */
+  cache->base = extract_unsigned_integer (buf, 8) + 16;
+
+  frame_unwind_register (next_frame, IA64_BSP_REGNUM, buf);
+  cache->bsp = extract_unsigned_integer (buf, 8);
+
+  frame_unwind_register (next_frame, IA64_CFM_REGNUM, buf);
+  cache->cfm = extract_unsigned_integer (buf, 8);
+  cache->sof = cache->cfm & 0x7f;
 
   ia64_sigtramp_frame_init_saved_regs (cache);
 
@@ -1927,7 +1977,11 @@ ia64_sigtramp_frame_this_id (struct fram
   struct ia64_frame_cache *cache =
     ia64_sigtramp_frame_cache (next_frame, this_cache);
 
-  (*this_id) = frame_id_build (cache->base, frame_pc_unwind (next_frame));
+  (*this_id) = frame_id_build_special (cache->base, frame_pc_unwind (next_frame), cache->bsp);
+  if (gdbarch_debug >= 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"sigtramp frame id: code %lx, stack %lx, special %lx, next_frame %p\n",
+			this_id->code_addr, this_id->stack_addr, cache->bsp, next_frame);
 }
 
 static void
@@ -1937,11 +1991,107 @@ ia64_sigtramp_frame_prev_register (struc
 				   enum lval_type *lvalp, CORE_ADDR *addrp,
 				   int *realnump, void *valuep)
 {
-  /* Make sure we've initialized the cache.  */
-  ia64_sigtramp_frame_cache (next_frame, this_cache);
+  char dummy_valp[MAX_REGISTER_SIZE];
+  char buf[MAX_REGISTER_SIZE];
+
+  struct ia64_frame_cache *cache =
+    ia64_sigtramp_frame_cache (next_frame, this_cache);
 
-  ia64_frame_prev_register (next_frame, this_cache, regnum,
-			    optimizedp, lvalp, addrp, realnump, valuep);
+  gdb_assert (regnum >= 0);
+
+  if (!target_has_registers)
+    error ("No registers.");
+
+  *optimizedp = 0;
+  *addrp = 0;
+  *lvalp = not_lval;
+  *realnump = -1;
+
+  /* Rather than check each time if valuep is non-null, supply a dummy buffer
+     when valuep is not supplied.  */
+  if (!valuep)
+    valuep = dummy_valp;
+  
+  memset (valuep, 0, register_size (current_gdbarch, regnum));
+ 
+  if (regnum == IA64_IP_REGNUM)
+    {
+      CORE_ADDR pc = 0;
+      CORE_ADDR addr = cache->saved_regs[IA64_VRAP_REGNUM];
+
+      if (addr != 0)
+	{
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, buf, register_size (current_gdbarch, IA64_IP_REGNUM));
+	  pc = extract_unsigned_integer (buf, 8);
+	}
+      pc &= ~0xf;
+      store_unsigned_integer (valuep, 8, pc);
+    }
+  else if (regnum == IA64_PSR_REGNUM)
+    {
+      ULONGEST slot_num = 0;
+      CORE_ADDR pc= 0;
+      CORE_ADDR psr = 0;
+      CORE_ADDR addr = cache->saved_regs[IA64_VRAP_REGNUM];
+
+      if (addr != 0)
+	{
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, buf, register_size (current_gdbarch, IA64_IP_REGNUM));
+	  pc = extract_unsigned_integer (buf, 8);
+	}
+      psr &= ~(3LL << 41);
+      slot_num = pc & 0x3LL;
+      psr |= (CORE_ADDR)slot_num << 41;
+      store_unsigned_integer (valuep, 8, psr);
+    }
+ else if ((regnum >= IA64_GR32_REGNUM && regnum <= IA64_GR127_REGNUM) ||
+	   (regnum >= V32_REGNUM && regnum <= V127_REGNUM))
+    {
+      CORE_ADDR addr = 0;
+      if (regnum >= V32_REGNUM)
+	regnum = IA64_GR32_REGNUM + (regnum - V32_REGNUM);
+      addr = cache->saved_regs[regnum];
+      if (addr != 0)
+	{
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, valuep, register_size (current_gdbarch, regnum));
+	}
+    }
+  else
+    {
+      CORE_ADDR addr = 0;
+      if (IA64_FR32_REGNUM <= regnum && regnum <= IA64_FR127_REGNUM)
+	{
+	  /* Fetch floating point register rename base from current
+	     frame marker for this frame.  */
+	  int rrb_fr = (cache->cfm >> 25) & 0x7f;
+
+	  /* Adjust the floating point register number to account for
+	     register rotation.  */
+	  regnum = IA64_FR32_REGNUM
+	         + ((regnum - IA64_FR32_REGNUM) + rrb_fr) % 96;
+	}
+
+      /* If we have stored a memory address, access the register.  */
+      addr = cache->saved_regs[regnum];
+      if (addr != 0)
+	{
+	  *lvalp = lval_memory;
+	  *addrp = addr;
+	  read_memory (addr, valuep, register_size (current_gdbarch, regnum));
+	}
+    }
+
+  if (gdbarch_debug >= 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"sigtramp prev register <%s> is %lx\n",
+			(((unsigned) regnum <= IA64_NAT127_REGNUM)
+			 ? ia64_register_names[regnum] : "r??"), extract_unsigned_integer (valuep, 8));
 }
 
 static const struct frame_unwind ia64_sigtramp_frame_unwind =
@@ -2473,12 +2623,20 @@ static struct frame_id
 ia64_unwind_dummy_id (struct gdbarch *gdbarch, struct frame_info *next_frame)
 {
   char buf[8];
-  CORE_ADDR sp;
+  CORE_ADDR sp, bsp;
 
   frame_unwind_register (next_frame, sp_regnum, buf);
   sp = extract_unsigned_integer (buf, 8);
 
-  return frame_id_build (sp, frame_pc_unwind (next_frame));
+  frame_unwind_register (next_frame, IA64_BSP_REGNUM, buf);
+  bsp = extract_unsigned_integer (buf, 8);
+
+  if (gdbarch_debug >= 1)
+    fprintf_unfiltered (gdb_stdlog,
+			"dummy frame id: code %lx, stack %lx, special %lx\n",
+			frame_pc_unwind (next_frame), sp, bsp);
+
+  return frame_id_build_special (sp, frame_pc_unwind (next_frame), bsp);
 }
 
 static CORE_ADDR