Re: [patch/rfc] regcache_raw_read_as_address() -> regcache_cooked_read_as_ulongest()

[Andrew Cagney <ac131313@ges.redhat.com>]

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> On Aug 12,  4:12pm, Daniel Jacobowitz wrote:
> 
> 
>> > I think the change is ok (i386 shows no regressions, the mips doesn't 
>> > use this code :-).  I'm just wondering about the names.  Perhaps: 
>> > regcache_cooked_read_signed() & regcache_cooked_read_unsigned()?
>> > 
>> > thoughts?
> 
>> 
>> Hmm, I like _read_signed and _read_unsigned... the _as_longest bit is
>> implicit.
> 
> 
> I agree with Daniel.

Good enough for me.

I took the liberty of revising the exact interface.  It uses a reference 
parameter, rather than function return, when passing back the result. 
The comment:

+/* NOTE: cagney/2002-08-13: At present GDB has no reliable mechanism
+   for indicating when a ``cooked'' register was constructed from
+   invalid or unavailable ``raw'' registers.  One fairly easy way of
+   adding such a mechanism would be for the cooked functions to return
+   a register valid indication.  Given the possibility of such a
+   change, the extract functions below use a reference parameter,
+   rather than a function result.  */

explains why.  I should note that this is a somewhat pervasive problem 
in GDB, there are few checks to ensure that a register is valid and 
those that do, check the raw register cache :-(

enjoy,
Andrew


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2002-08-12  Andrew Cagney  <cagney@redhat.com>

	* regcache.c (regcache_raw_read_as_address): Delete function.
	(regcache_cooked_read_signed): New function.
	(regcache_cooked_read_unsigned): New function.
	* regcache.h (regcache_cooked_read_signed): Declare.
	(regcache_cooked_read_unsigned): Declare.
	(regcache_raw_read_as_address): Delete declaration.

	* blockframe.c (generic_read_register_dummy): Use
	regcache_cooked_read_unsigned.
	* i386-tdep.c (i386_extract_struct_value_address): Use
	regcache_cooked_read_unsigned.

Index: blockframe.c
===================================================================
RCS file: /cvs/src/src/gdb/blockframe.c,v
retrieving revision 1.35
diff -u -r1.35 blockframe.c
--- blockframe.c	9 Aug 2002 18:26:15 -0000	1.35
+++ blockframe.c	13 Aug 2002 13:39:24 -0000
@@ -1215,7 +1215,20 @@
   struct regcache *dummy_regs = generic_find_dummy_frame (pc, fp);
 
   if (dummy_regs)
-    return regcache_raw_read_as_address (dummy_regs, regno);
+    {
+      /* NOTE: cagney/2002-08-12: Replaced a call to
+	 regcache_raw_read_as_address() with a call to
+	 regcache_cooked_read_unsigned().  The old, ...as_address
+	 function was eventually calling extract_unsigned_integer (via
+	 extract_address) to unpack the registers value.  The below is
+	 doing an unsigned extract so that it is functionally
+	 equivalent.  The read needs to be cooked as, otherwise, it
+	 will never correctly return the value of a register in the
+	 [NUM_REGS .. NUM_REGS+NUM_PSEUDO_REGS) range.  */
+      ULONGEST val;
+      regcache_cooked_read_unsigned (dummy_regs, regno, &val);
+      return val;
+    }
   else
     return 0;
 }
Index: i386-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-tdep.c,v
retrieving revision 1.74
diff -u -r1.74 i386-tdep.c
--- i386-tdep.c	12 Aug 2002 19:05:33 -0000	1.74
+++ i386-tdep.c	13 Aug 2002 13:39:25 -0000
@@ -1028,7 +1028,18 @@
 static CORE_ADDR
 i386_extract_struct_value_address (struct regcache *regcache)
 {
-  return regcache_raw_read_as_address (regcache, LOW_RETURN_REGNUM);
+  /* NOTE: cagney/2002-08-12: Replaced a call to
+     regcache_raw_read_as_address() with a call to
+     regcache_cooked_read_unsigned().  The old, ...as_address function
+     was eventually calling extract_unsigned_integer (via
+     extract_address) to unpack the registers value.  The below is
+     doing an unsigned extract so that it is functionally equivalent.
+     The read needs to be cooked as, otherwise, it will never
+     correctly return the value of a register in the [NUM_REGS
+     .. NUM_REGS+NUM_PSEUDO_REGS) range.  */
+  ULONGEST val;
+  regcache_cooked_read_unsigned (regcache, LOW_RETURN_REGNUM, &val);
+  return val;
 }
 \f
 
Index: regcache.c
===================================================================
RCS file: /cvs/src/src/gdb/regcache.c,v
retrieving revision 1.50
diff -u -r1.50 regcache.c
--- regcache.c	10 Aug 2002 02:00:16 -0000	1.50
+++ regcache.c	13 Aug 2002 13:39:25 -0000
@@ -366,17 +366,6 @@
   return regcache->raw_register_valid_p[regnum];
 }
 
-CORE_ADDR
-regcache_raw_read_as_address (struct regcache *regcache, int regnum)
-{
-  char *buf;
-  gdb_assert (regcache != NULL);
-  gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
-  buf = alloca (regcache->descr->sizeof_register[regnum]);
-  regcache_raw_read (regcache, regnum, buf);
-  return extract_address (buf, regcache->descr->sizeof_register[regnum]);
-}
-
 char *
 deprecated_grub_regcache_for_registers (struct regcache *regcache)
 {
@@ -694,6 +683,32 @@
   else
     gdbarch_pseudo_register_read (regcache->descr->gdbarch, regcache,
 				  regnum, buf);
+}
+
+void
+regcache_cooked_read_signed (struct regcache *regcache, int regnum,
+			     LONGEST *val)
+{
+  char *buf;
+  gdb_assert (regcache != NULL);
+  gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
+  buf = alloca (regcache->descr->sizeof_register[regnum]);
+  regcache_cooked_read (regcache, regnum, buf);
+  (*val) = extract_signed_integer (buf,
+				   regcache->descr->sizeof_register[regnum]);
+}
+
+void
+regcache_cooked_read_unsigned (struct regcache *regcache, int regnum,
+			       ULONGEST *val)
+{
+  char *buf;
+  gdb_assert (regcache != NULL);
+  gdb_assert (regnum >= 0 && regnum < regcache->descr->nr_raw_registers);
+  buf = alloca (regcache->descr->sizeof_register[regnum]);
+  regcache_cooked_read (regcache, regnum, buf);
+  (*val) = extract_unsigned_integer (buf,
+				     regcache->descr->sizeof_register[regnum]);
 }
 
 /* Write register REGNUM at MYADDR to the target.  MYADDR points at
Index: regcache.h
===================================================================
RCS file: /cvs/src/src/gdb/regcache.h,v
retrieving revision 1.12
diff -u -r1.12 regcache.h
--- regcache.h	2 Aug 2002 18:08:31 -0000	1.12
+++ regcache.h	13 Aug 2002 13:39:25 -0000
@@ -39,12 +39,25 @@
 void regcache_raw_write (struct regcache *regcache, int rawnum,
 			 const void *buf);
 int regcache_valid_p (struct regcache *regcache, int regnum);
-CORE_ADDR regcache_raw_read_as_address (struct regcache *regcache, int rawnum);
 
 /* Transfer a cooked register [0..NUM_REGS+NUM_PSEUDO_REGS).  */
 void regcache_cooked_read (struct regcache *regcache, int rawnum, void *buf);
 void regcache_cooked_write (struct regcache *regcache, int rawnum,
 			    const void *buf);
+
+/* NOTE: cagney/2002-08-13: At present GDB has no reliable mechanism
+   for indicating when a ``cooked'' register was constructed from
+   invalid or unavailable ``raw'' registers.  One fairly easy way of
+   adding such a mechanism would be for the cooked functions to return
+   a register valid indication.  Given the possibility of such a
+   change, the extract functions below use a reference parameter,
+   rather than a function result.  */
+
+/* Read a register as a signed/unsigned quantity.  */
+extern void regcache_cooked_read_signed (struct regcache *regcache,
+					 int regnum, LONGEST *val);
+extern void regcache_cooked_read_unsigned (struct regcache *regcache,
+					   int regnum, ULONGEST *val);
 
 /* Transfer a raw register [0..NUM_REGS) between the regcache and the
    target.  These functions are called by the target in response to a