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* [RFC][2/2] Rework value_from_register
@ 2006-12-08 15:52 Ulrich Weigand
  2006-12-16  1:16 ` Jim Blandy
  2007-01-04 21:28 ` Jim Blandy
  0 siblings, 2 replies; 5+ messages in thread
From: Ulrich Weigand @ 2006-12-08 15:52 UTC (permalink / raw)
  To: gdb-patches; +Cc: jimb, drow

Hello,

based on the value_from_register cleanup patch, this patch adds a new
gdbarch method, gdbarch_value_from_register, that back-ends can use
instead of convert_register_p / value_to_register / register_to_value.

The idea is that the gdbarch routine sets up the contents of the
struct value such that subsequently, common code is able to access
the register (including sub-values) without further interaction
with gdbarch methods.

This currently works only on spu and s390, because there we simply
need to set the proper value_offset, and everything else works
automatically.

In the future, assuming Jim's per-value read/write methods are
implemented, the gdbarch_value_from_register routine could set
those to effect any arbitrary change; that solution would then
completly replace the existing value_to_register / register_to_value.

Until that is implemented, I've left in the old way as well.

I've considered one interface alternative; the patch below has
common code generate the struct value and fill in default values;
the gdbarch_value_from_register routine gets the struct value is
may change things as appropriate.  The alternative would be to
have gdbarch_value_from_register fully construct the value
itself (possibly falling back on a common helper routine).
Any preference on that question?

Tested without regressions on spu-elf, s390-ibm-linux, s390x-ibm-linux.
Fixes all the currently existing sub-value problems on spu.

Bye,
Ulrich


ChangeLog:

	* gdbarch.sh (value_from_register): New gdbarch function.
	* gdbarch.c, gdbarch.h: Regenerate.
	* findvar.c (default_value_from_register): New function.
	(value_from_register): Use gdbarch_value_from_register.
	* value.h (default_value_from_register): Declare.
	* spu-tdep.c (spu_convert_register_p, spu_register_to_value,
	spu_value_to_register): Remove.
	(spu_value_from_register): New function.
	(spu_gdbarch_init): Do not call set_gdbarch_convert_register_p,
	set_gdbarch_register_to_value, set_gdbarch_value_to_register.
	Call set_gdbarch_value_from_register.
	* s390-tdep.c (s390_convert_register_p, s390_register_to_value,
	s390_value_to_register): Remove.
	(s390_value_from_register): New function.
	(s390_gdbarch_init): Do not call set_gdbarch_convert_register_p,
	set_gdbarch_register_to_value, set_gdbarch_value_to_register.
	Call set_gdbarch_value_from_register.

diff -urp gdb-orig/gdb/findvar.c gdb-head/gdb/findvar.c

diff -urp gdb-orig/gdb/findvar.c gdb-head/gdb/findvar.c
--- gdb-orig/gdb/findvar.c	2006-12-08 14:54:18.000000000 +0100
+++ gdb-head/gdb/findvar.c	2006-12-08 15:27:51.647466736 +0100
@@ -599,6 +599,26 @@ addresses have not been bound by the dyn
   return v;
 }
 
+/* Install default attributes for register values.  */
+
+void
+default_value_from_register (struct gdbarch *gdbarch, struct value *value)
+{
+  int len = TYPE_LENGTH (value_type (value));
+  int regnum = VALUE_REGNUM (value);
+
+  /* Any structure stored in more than one register will always be
+     an integral number of registers.  Otherwise, you need to do
+     some fiddling with the last register copied here for little
+     endian machines.  */
+  if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
+      && len < register_size (gdbarch, regnum))
+    /* Big-endian, and we want less than full size.  */
+    set_value_offset (value, register_size (gdbarch, regnum) - len);
+  else
+    set_value_offset (value, 0);
+}
+
 /* Return a value of type TYPE, stored in register REGNUM, in frame FRAME.  */
 
 struct value *
@@ -628,16 +648,8 @@ value_from_register (struct type *type, 
       struct gdbarch *gdbarch = get_frame_arch (frame);
       int len = TYPE_LENGTH (type);
 
-      /* Any structure stored in more than one register will always be
-         an integral number of registers.  Otherwise, you need to do
-         some fiddling with the last register copied here for little
-         endian machines.  */
-      if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG
-	  && len < register_size (gdbarch, regnum))
-	/* Big-endian, and we want less than full size.  */
-	set_value_offset (v, register_size (gdbarch, regnum) - len);
-      else
-	set_value_offset (v, 0);
+      /* Install value attributes.  */
+      gdbarch_value_from_register (gdbarch, v);
 
       /* Get the data.  */
       if (!get_frame_register_bytes (frame, regnum, value_offset (v), len,
diff -urp gdb-orig/gdb/gdbarch.c gdb-head/gdb/gdbarch.c
--- gdb-orig/gdb/gdbarch.c	2006-12-08 14:38:45.000000000 +0100
+++ gdb-head/gdb/gdbarch.c	2006-12-08 15:19:20.115487104 +0100
@@ -183,6 +183,7 @@ struct gdbarch
   gdbarch_convert_register_p_ftype *convert_register_p;
   gdbarch_register_to_value_ftype *register_to_value;
   gdbarch_value_to_register_ftype *value_to_register;
+  gdbarch_value_from_register_ftype *value_from_register;
   gdbarch_pointer_to_address_ftype *pointer_to_address;
   gdbarch_address_to_pointer_ftype *address_to_pointer;
   gdbarch_integer_to_address_ftype *integer_to_address;
@@ -309,6 +310,7 @@ struct gdbarch startup_gdbarch =
   0,  /* convert_register_p */
   0,  /* register_to_value */
   0,  /* value_to_register */
+  default_value_from_register,  /* value_from_register */
   0,  /* pointer_to_address */
   0,  /* address_to_pointer */
   0,  /* integer_to_address */
@@ -429,6 +431,7 @@ gdbarch_alloc (const struct gdbarch_info
   current_gdbarch->cannot_fetch_register = cannot_register_not;
   current_gdbarch->cannot_store_register = cannot_register_not;
   current_gdbarch->convert_register_p = generic_convert_register_p;
+  current_gdbarch->value_from_register = default_value_from_register;
   current_gdbarch->pointer_to_address = unsigned_pointer_to_address;
   current_gdbarch->address_to_pointer = unsigned_address_to_pointer;
   current_gdbarch->return_value = legacy_return_value;
@@ -562,6 +565,8 @@ verify_gdbarch (struct gdbarch *current_
   /* Skip verify of cannot_store_register, invalid_p == 0 */
   /* Skip verify of get_longjmp_target, has predicate */
   /* Skip verify of convert_register_p, invalid_p == 0 */
+  if (current_gdbarch->value_from_register == default_value_from_register)
+    fprintf_unfiltered (log, "\n\tvalue_from_register");
   /* Skip verify of pointer_to_address, invalid_p == 0 */
   /* Skip verify of address_to_pointer, invalid_p == 0 */
   /* Skip verify of integer_to_address, has predicate */
@@ -1586,6 +1591,9 @@ gdbarch_dump (struct gdbarch *current_gd
   fprintf_unfiltered (file,
                       "gdbarch_dump: unwind_sp = <0x%lx>\n",
                       (long) current_gdbarch->unwind_sp);
+  fprintf_unfiltered (file,
+                      "gdbarch_dump: value_from_register = <0x%lx>\n",
+                      (long) current_gdbarch->value_from_register);
 #ifdef VALUE_TO_REGISTER
   fprintf_unfiltered (file,
                       "gdbarch_dump: %s # %s\n",
@@ -2636,6 +2644,23 @@ set_gdbarch_value_to_register (struct gd
   gdbarch->value_to_register = value_to_register;
 }
 
+void
+gdbarch_value_from_register (struct gdbarch *gdbarch, struct value *value)
+{
+  gdb_assert (gdbarch != NULL);
+  gdb_assert (gdbarch->value_from_register != NULL);
+  if (gdbarch_debug >= 2)
+    fprintf_unfiltered (gdb_stdlog, "gdbarch_value_from_register called\n");
+  gdbarch->value_from_register (gdbarch, value);
+}
+
+void
+set_gdbarch_value_from_register (struct gdbarch *gdbarch,
+                                 gdbarch_value_from_register_ftype value_from_register)
+{
+  gdbarch->value_from_register = value_from_register;
+}
+
 CORE_ADDR
 gdbarch_pointer_to_address (struct gdbarch *gdbarch, struct type *type, const gdb_byte *buf)
 {
diff -urp gdb-orig/gdb/gdbarch.h gdb-head/gdb/gdbarch.h
--- gdb-orig/gdb/gdbarch.h	2006-12-08 14:38:45.000000000 +0100
+++ gdb-head/gdb/gdbarch.h	2006-12-08 15:19:00.783497440 +0100
@@ -704,6 +704,10 @@ extern void set_gdbarch_value_to_registe
 #define VALUE_TO_REGISTER(frame, regnum, type, buf) (gdbarch_value_to_register (current_gdbarch, frame, regnum, type, buf))
 #endif
 
+typedef void (gdbarch_value_from_register_ftype) (struct gdbarch *gdbarch, struct value *value);
+extern void gdbarch_value_from_register (struct gdbarch *gdbarch, struct value *value);
+extern void set_gdbarch_value_from_register (struct gdbarch *gdbarch, gdbarch_value_from_register_ftype *value_from_register);
+
 typedef CORE_ADDR (gdbarch_pointer_to_address_ftype) (struct type *type, const gdb_byte *buf);
 extern CORE_ADDR gdbarch_pointer_to_address (struct gdbarch *gdbarch, struct type *type, const gdb_byte *buf);
 extern void set_gdbarch_pointer_to_address (struct gdbarch *gdbarch, gdbarch_pointer_to_address_ftype *pointer_to_address);
diff -urp gdb-orig/gdb/gdbarch.sh gdb-head/gdb/gdbarch.sh
--- gdb-orig/gdb/gdbarch.sh	2006-12-08 14:38:45.000000000 +0100
+++ gdb-head/gdb/gdbarch.sh	2006-12-08 15:18:51.648421896 +0100
@@ -496,6 +496,7 @@ v:=:int:believe_pcc_promotion:::::::
 f:=:int:convert_register_p:int regnum, struct type *type:regnum, type:0:generic_convert_register_p::0
 f:=:void:register_to_value:struct frame_info *frame, int regnum, struct type *type, gdb_byte *buf:frame, regnum, type, buf:0
 f:=:void:value_to_register:struct frame_info *frame, int regnum, struct type *type, const gdb_byte *buf:frame, regnum, type, buf:0
+m::void:value_from_register:struct value *value:value::default_value_from_register
 #
 f:=:CORE_ADDR:pointer_to_address:struct type *type, const gdb_byte *buf:type, buf::unsigned_pointer_to_address::0
 f:=:void:address_to_pointer:struct type *type, gdb_byte *buf, CORE_ADDR addr:type, buf, addr::unsigned_address_to_pointer::0
diff -urp gdb-orig/gdb/s390-tdep.c gdb-head/gdb/s390-tdep.c
--- gdb-orig/gdb/s390-tdep.c	2006-11-28 21:46:03.000000000 +0100
+++ gdb-head/gdb/s390-tdep.c	2006-12-08 15:28:09.919485824 +0100
@@ -306,36 +306,16 @@ s390x_pseudo_register_write (struct gdba
 /* 'float' values are stored in the upper half of floating-point
    registers, even though we are otherwise a big-endian platform.  */
 
-static int
-s390_convert_register_p (int regno, struct type *type)
-{
-  return (regno >= S390_F0_REGNUM && regno <= S390_F15_REGNUM)
-	 && TYPE_LENGTH (type) < 8;
-}
-
 static void
-s390_register_to_value (struct frame_info *frame, int regnum,
-                        struct type *valtype, gdb_byte *out)
+s390_value_from_register (struct gdbarch *gdbarch, struct value *value)
 {
-  gdb_byte in[8];
-  int len = TYPE_LENGTH (valtype);
-  gdb_assert (len < 8);
+  int len = TYPE_LENGTH (value_type (value));
+  int regnum = VALUE_REGNUM (value);
 
-  get_frame_register (frame, regnum, in);
-  memcpy (out, in, len);
-}
+  default_value_from_register (gdbarch, value);
 
-static void
-s390_value_to_register (struct frame_info *frame, int regnum,
-                        struct type *valtype, const gdb_byte *in)
-{
-  gdb_byte out[8];
-  int len = TYPE_LENGTH (valtype);
-  gdb_assert (len < 8);
-
-  memset (out, 0, 8);
-  memcpy (out, in, len);
-  put_frame_register (frame, regnum, out);
+  if (regnum >= S390_F0_REGNUM && regnum <= S390_F15_REGNUM && len < 8)
+    set_value_offset (value, 0);
 }
 
 /* Register groups.  */
@@ -2411,9 +2391,7 @@ s390_gdbarch_init (struct gdbarch_info i
   set_gdbarch_stab_reg_to_regnum (gdbarch, s390_dwarf_reg_to_regnum);
   set_gdbarch_dwarf_reg_to_regnum (gdbarch, s390_dwarf_reg_to_regnum);
   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, s390_dwarf_reg_to_regnum);
-  set_gdbarch_convert_register_p (gdbarch, s390_convert_register_p);
-  set_gdbarch_register_to_value (gdbarch, s390_register_to_value);
-  set_gdbarch_value_to_register (gdbarch, s390_value_to_register);
+  set_gdbarch_value_from_register (gdbarch, s390_value_from_register);
   set_gdbarch_register_reggroup_p (gdbarch, s390_register_reggroup_p);
   set_gdbarch_regset_from_core_section (gdbarch,
                                         s390_regset_from_core_section);
diff -urp gdb-orig/gdb/spu-tdep.c gdb-head/gdb/spu-tdep.c
--- gdb-orig/gdb/spu-tdep.c	2006-11-24 15:00:40.000000000 +0100
+++ gdb-head/gdb/spu-tdep.c	2006-12-08 15:28:21.653433624 +0100
@@ -143,37 +143,19 @@ spu_pseudo_register_write (struct gdbarc
 
 /* Value conversion -- access scalar values at the preferred slot.  */
 
-static int
-spu_convert_register_p (int regno, struct type *type)
-{
-  return regno < SPU_NUM_GPRS && TYPE_LENGTH (type) < 16;
-}
-
 static void
-spu_register_to_value (struct frame_info *frame, int regnum,
-                       struct type *valtype, gdb_byte *out)
+spu_value_from_register (struct gdbarch *gdbarch, struct value *value)
 {
-  gdb_byte in[16];
-  int len = TYPE_LENGTH (valtype);
-  int preferred_slot = len < 4 ? 4 - len : 0;
-  gdb_assert (len < 16);
+  int len = TYPE_LENGTH (value_type (value));
+  int regnum = VALUE_REGNUM (value);
 
-  get_frame_register (frame, regnum, in);
-  memcpy (out, in + preferred_slot, len);
-}
+  default_value_from_register (gdbarch, value);
 
-static void
-spu_value_to_register (struct frame_info *frame, int regnum,
-                       struct type *valtype, const gdb_byte *in)
-{
-  gdb_byte out[16];
-  int len = TYPE_LENGTH (valtype);
-  int preferred_slot = len < 4 ? 4 - len : 0;
-  gdb_assert (len < 16);
-
-  memset (out, 0, 16);
-  memcpy (out + preferred_slot, in, len);
-  put_frame_register (frame, regnum, out);
+  if (regnum < SPU_NUM_GPRS && len < 16)
+    {
+      int preferred_slot = len < 4 ? 4 - len : 0;
+      set_value_offset (value, preferred_slot);
+    }
 }
 
 /* Register groups.  */
@@ -1048,9 +1030,7 @@ spu_gdbarch_init (struct gdbarch_info in
   set_gdbarch_register_type (gdbarch, spu_register_type);
   set_gdbarch_pseudo_register_read (gdbarch, spu_pseudo_register_read);
   set_gdbarch_pseudo_register_write (gdbarch, spu_pseudo_register_write);
-  set_gdbarch_convert_register_p (gdbarch, spu_convert_register_p);
-  set_gdbarch_register_to_value (gdbarch, spu_register_to_value);
-  set_gdbarch_value_to_register (gdbarch, spu_value_to_register);
+  set_gdbarch_value_from_register (gdbarch, spu_value_from_register);
   set_gdbarch_register_reggroup_p (gdbarch, spu_register_reggroup_p);
 
   /* Data types.  */
diff -urp gdb-orig/gdb/value.h gdb-head/gdb/value.h
--- gdb-orig/gdb/value.h	2006-11-24 17:56:28.000000000 +0100
+++ gdb-head/gdb/value.h	2006-12-08 15:20:29.836407912 +0100
@@ -279,6 +279,9 @@ extern struct value *value_from_string (
 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 
+extern void default_value_from_register (struct gdbarch *gdbarch,
+					 struct value *value);
+
 extern struct value *value_from_register (struct type *type, int regnum,
 					  struct frame_info *frame);
 
-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com


^ permalink raw reply	[flat|nested] 5+ messages in thread
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Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2006-12-08 15:52 [RFC][2/2] Rework value_from_register Ulrich Weigand
2006-12-16  1:16 ` Jim Blandy
2006-12-22 17:44   ` Ulrich Weigand
2007-01-04 21:28 ` Jim Blandy
2007-01-08 20:07   ` Ulrich Weigand

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