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[patch/rfc; rfa:m68hc11] Delete RETURN_VALUE_ON_STACK


Hello,

This converts the m68hc11 to the return_value architecture method allowing us to delete RETURN_VALUE_ON_STACK. In doing this I assumed that m68hc11 ABI didn't guarentee that a struct-return address wasn't preserved across a function call and, hence, deleted the EXTRACT_STRUCT_VALUE_ADDRESS logic.

Stephane, does the m68hc11 change look ok?
Andrew
2004-06-12  Andrew Cagney  <cagney@gnu.org>

	* gdbarch.sh (RETURN_VALUE_ON_STACK): Delete method.
	* gdbarch.h, gdbarch.c: Re-generate.
	* m68hc11-tdep.c (m68hc11_return_value_on_stack): Delete function.
	(m68hc11_use_struct_convention): Delete function.
	(m68hc11_extract_struct_value_address): Delete function.
	(m68hc11_return_value): New function.
	(m68hc11_gdbarch_init): Instead of store_return_value,
	extract_return_value, return_value_on_stack,
	deprecated_extract_struct_value_address and use_struct_convention,
	set return_value.
	* values.c (using_struct_return): Do not call
	RETURN_VALUE_ON_STACK.
	* arch-utils.h (generic_return_value_on_stack_not): Delete
	declaration.
	* arch-utils.c (generic_return_value_on_stack_not): Delete
	function.

Index: doc/ChangeLog
2004-06-12  Andrew Cagney  <cagney@gnu.org>

	* gdbint.texinfo (Target Architecture Definition): Delete
	description of RETURN_VALUE_ON_STACK.

Index: arch-utils.c
===================================================================
RCS file: /cvs/src/src/gdb/arch-utils.c,v
retrieving revision 1.118
diff -p -u -r1.118 arch-utils.c
--- arch-utils.c	9 Jun 2004 21:26:48 -0000	1.118
+++ arch-utils.c	12 Jun 2004 19:21:58 -0000
@@ -84,12 +84,6 @@ legacy_register_sim_regno (int regnum)
     return LEGACY_SIM_REGNO_IGNORE;
 }
 
-int
-generic_return_value_on_stack_not (struct type *type)
-{
-  return 0;
-}
-
 CORE_ADDR
 generic_skip_trampoline_code (CORE_ADDR pc)
 {
Index: arch-utils.h
===================================================================
RCS file: /cvs/src/src/gdb/arch-utils.h,v
retrieving revision 1.71
diff -p -u -r1.71 arch-utils.h
--- arch-utils.h	9 Jun 2004 21:26:48 -0000	1.71
+++ arch-utils.h	12 Jun 2004 19:21:58 -0000
@@ -43,11 +43,6 @@ extern gdbarch_store_return_value_ftype 
    address passed as an invisible first argument to the function.  */
 extern gdbarch_use_struct_convention_ftype always_use_struct_convention;
 
-/* Only structures, unions, and arrays are returned using the struct
-   convention.  Note that arrays are never passed by value in the C
-   language family, so that case is irrelevant for C.  */
-extern gdbarch_return_value_on_stack_ftype generic_return_value_on_stack_not;
-
 /* Typical remote_translate_xfer_address */
 extern gdbarch_remote_translate_xfer_address_ftype generic_remote_translate_xfer_address;
 
Index: gdbarch.c
===================================================================
RCS file: /cvs/src/src/gdb/gdbarch.c,v
retrieving revision 1.294
diff -p -u -r1.294 gdbarch.c
--- gdbarch.c	10 Jun 2004 13:22:05 -0000	1.294
+++ gdbarch.c	12 Jun 2004 19:21:59 -0000
@@ -184,7 +184,6 @@ struct gdbarch
   gdbarch_deprecated_pop_frame_ftype *deprecated_pop_frame;
   gdbarch_deprecated_store_struct_return_ftype *deprecated_store_struct_return;
   gdbarch_return_value_ftype *return_value;
-  gdbarch_return_value_on_stack_ftype *return_value_on_stack;
   gdbarch_extract_return_value_ftype *extract_return_value;
   gdbarch_store_return_value_ftype *store_return_value;
   gdbarch_deprecated_extract_return_value_ftype *deprecated_extract_return_value;
@@ -333,7 +332,6 @@ struct gdbarch startup_gdbarch =
   0,  /* deprecated_pop_frame */
   0,  /* deprecated_store_struct_return */
   0,  /* return_value */
-  0,  /* return_value_on_stack */
   0,  /* extract_return_value */
   0,  /* store_return_value */
   0,  /* deprecated_extract_return_value */
@@ -463,7 +461,6 @@ gdbarch_alloc (const struct gdbarch_info
   current_gdbarch->convert_register_p = generic_convert_register_p;
   current_gdbarch->pointer_to_address = unsigned_pointer_to_address;
   current_gdbarch->address_to_pointer = unsigned_address_to_pointer;
-  current_gdbarch->return_value_on_stack = generic_return_value_on_stack_not;
   current_gdbarch->extract_return_value = legacy_extract_return_value;
   current_gdbarch->store_return_value = legacy_store_return_value;
   current_gdbarch->use_struct_convention = generic_use_struct_convention;
@@ -611,7 +608,6 @@ verify_gdbarch (struct gdbarch *current_
   /* Skip verify of deprecated_pop_frame, has predicate */
   /* Skip verify of deprecated_store_struct_return, has predicate */
   /* Skip verify of return_value, has predicate */
-  /* Skip verify of return_value_on_stack, invalid_p == 0 */
   /* Skip verify of extract_return_value, invalid_p == 0 */
   /* Skip verify of store_return_value, invalid_p == 0 */
   /* Skip verify of use_struct_convention, invalid_p == 0 */
@@ -1809,16 +1805,6 @@ gdbarch_dump (struct gdbarch *current_gd
   fprintf_unfiltered (file,
                       "gdbarch_dump: remote_translate_xfer_address = 0x%08lx\n",
                       (long) current_gdbarch->remote_translate_xfer_address);
-#ifdef RETURN_VALUE_ON_STACK
-  fprintf_unfiltered (file,
-                      "gdbarch_dump: %s # %s\n",
-                      "RETURN_VALUE_ON_STACK(type)",
-                      XSTRING (RETURN_VALUE_ON_STACK (type)));
-  fprintf_unfiltered (file,
-                      "gdbarch_dump: RETURN_VALUE_ON_STACK = <0x%08lx>\n",
-                      (long) current_gdbarch->return_value_on_stack
-                      /*RETURN_VALUE_ON_STACK ()*/);
-#endif
 #ifdef SDB_REG_TO_REGNUM
   fprintf_unfiltered (file,
                       "gdbarch_dump: %s # %s\n",
@@ -3576,23 +3562,6 @@ set_gdbarch_return_value (struct gdbarch
   gdbarch->return_value = return_value;
 }
 
-int
-gdbarch_return_value_on_stack (struct gdbarch *gdbarch, struct type *type)
-{
-  gdb_assert (gdbarch != NULL);
-  gdb_assert (gdbarch->return_value_on_stack != NULL);
-  if (gdbarch_debug >= 2)
-    fprintf_unfiltered (gdb_stdlog, "gdbarch_return_value_on_stack called\n");
-  return gdbarch->return_value_on_stack (type);
-}
-
-void
-set_gdbarch_return_value_on_stack (struct gdbarch *gdbarch,
-                                   gdbarch_return_value_on_stack_ftype return_value_on_stack)
-{
-  gdbarch->return_value_on_stack = return_value_on_stack;
-}
-
 void
 gdbarch_extract_return_value (struct gdbarch *gdbarch, struct type *type, struct regcache *regcache, void *valbuf)
 {
Index: gdbarch.h
===================================================================
RCS file: /cvs/src/src/gdb/gdbarch.h,v
retrieving revision 1.256
diff -p -u -r1.256 gdbarch.h
--- gdbarch.h	10 Jun 2004 13:22:06 -0000	1.256
+++ gdbarch.h	12 Jun 2004 19:22:02 -0000
@@ -1155,19 +1155,8 @@ typedef enum return_value_convention (gd
 extern enum return_value_convention gdbarch_return_value (struct gdbarch *gdbarch, struct type *valtype, struct regcache *regcache, void *readbuf, const void *writebuf);
 extern void set_gdbarch_return_value (struct gdbarch *gdbarch, gdbarch_return_value_ftype *return_value);
 
-/* The deprecated methods RETURN_VALUE_ON_STACK, EXTRACT_RETURN_VALUE,
-   STORE_RETURN_VALUE and USE_STRUCT_CONVENTION have all been folded
-   into RETURN_VALUE. */
-
-typedef int (gdbarch_return_value_on_stack_ftype) (struct type *type);
-extern int gdbarch_return_value_on_stack (struct gdbarch *gdbarch, struct type *type);
-extern void set_gdbarch_return_value_on_stack (struct gdbarch *gdbarch, gdbarch_return_value_on_stack_ftype *return_value_on_stack);
-#if (GDB_MULTI_ARCH > GDB_MULTI_ARCH_PARTIAL) && defined (RETURN_VALUE_ON_STACK)
-#error "Non multi-arch definition of RETURN_VALUE_ON_STACK"
-#endif
-#if !defined (RETURN_VALUE_ON_STACK)
-#define RETURN_VALUE_ON_STACK(type) (gdbarch_return_value_on_stack (current_gdbarch, type))
-#endif
+/* The deprecated methods EXTRACT_RETURN_VALUE, STORE_RETURN_VALUE and
+   USE_STRUCT_CONVENTION have all been folded into RETURN_VALUE. */
 
 typedef void (gdbarch_extract_return_value_ftype) (struct type *type, struct regcache *regcache, void *valbuf);
 extern void gdbarch_extract_return_value (struct gdbarch *gdbarch, struct type *type, struct regcache *regcache, void *valbuf);
Index: gdbarch.sh
===================================================================
RCS file: /cvs/src/src/gdb/gdbarch.sh,v
retrieving revision 1.321
diff -p -u -r1.321 gdbarch.sh
--- gdbarch.sh	10 Jun 2004 13:22:06 -0000	1.321
+++ gdbarch.sh	12 Jun 2004 19:22:02 -0000
@@ -562,11 +562,9 @@ F:2:DEPRECATED_STORE_STRUCT_RETURN:void:
 
 M:::enum return_value_convention:return_value:struct type *valtype, struct regcache *regcache, void *readbuf, const void *writebuf:valtype, regcache, readbuf, writebuf
 
-# The deprecated methods RETURN_VALUE_ON_STACK, EXTRACT_RETURN_VALUE,
-# STORE_RETURN_VALUE and USE_STRUCT_CONVENTION have all been folded
-# into RETURN_VALUE.
+# The deprecated methods EXTRACT_RETURN_VALUE, STORE_RETURN_VALUE and
+# USE_STRUCT_CONVENTION have all been folded into RETURN_VALUE.
 
-f:2:RETURN_VALUE_ON_STACK:int:return_value_on_stack:struct type *type:type:::generic_return_value_on_stack_not::0
 f:2:EXTRACT_RETURN_VALUE:void:extract_return_value:struct type *type, struct regcache *regcache, void *valbuf:type, regcache, valbuf:::legacy_extract_return_value::0
 f:2:STORE_RETURN_VALUE:void:store_return_value:struct type *type, struct regcache *regcache, const void *valbuf:type, regcache, valbuf:::legacy_store_return_value::0
 f:2:DEPRECATED_EXTRACT_RETURN_VALUE:void:deprecated_extract_return_value:struct type *type, char *regbuf, char *valbuf:type, regbuf, valbuf
Index: m68hc11-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/m68hc11-tdep.c,v
retrieving revision 1.102
diff -p -u -r1.102 m68hc11-tdep.c
--- m68hc11-tdep.c	7 Jun 2004 02:02:51 -0000	1.102
+++ m68hc11-tdep.c	12 Jun 2004 19:22:03 -0000
@@ -1332,31 +1332,24 @@ m68hc11_extract_return_value (struct typ
     }
 }
 
-/* Should call_function allocate stack space for a struct return?  */
-static int
-m68hc11_use_struct_convention (int gcc_p, struct type *type)
-{
-  return (TYPE_CODE (type) == TYPE_CODE_STRUCT
-          || TYPE_CODE (type) == TYPE_CODE_UNION
-          || TYPE_LENGTH (type) > 4);
-}
-
-static int
-m68hc11_return_value_on_stack (struct type *type)
-{
-  return TYPE_LENGTH (type) > 4;
-}
-
-/* Extract from an array REGBUF containing the (raw) register state
-   the address in which a function should return its structure value,
-   as a CORE_ADDR (or an expression that can be used as one).  */
-static CORE_ADDR
-m68hc11_extract_struct_value_address (struct regcache *regcache)
-{
-  char buf[M68HC11_REG_SIZE];
-
-  regcache_cooked_read (regcache, HARD_D_REGNUM, buf);
-  return extract_unsigned_integer (buf, M68HC11_REG_SIZE);
+enum return_value_convention
+m68hc11_return_value (struct gdbarch *gdbarch, struct type *valtype,
+		      struct regcache *regcache, void *readbuf,
+		      const void *writebuf)
+{
+  if (TYPE_CODE (valtype) == TYPE_CODE_STRUCT
+      || TYPE_CODE (valtype) == TYPE_CODE_UNION
+      || TYPE_CODE (valtype) == TYPE_CODE_ARRAY 
+      || TYPE_LENGTH (valtype) > 4)
+    return RETURN_VALUE_STRUCT_CONVENTION;
+  else
+    {
+      if (readbuf != NULL)
+	m68hc11_extract_return_value (valtype, regcache, readbuf);
+      if (writebuf != NULL)
+	m68hc11_store_return_value (valtype, regcache, writebuf);
+      return RETURN_VALUE_REGISTER_CONVENTION;
+    }
 }
 
 /* Test whether the ELF symbol corresponds to a function using rtc or
@@ -1539,12 +1532,7 @@ m68hc11_gdbarch_init (struct gdbarch_inf
 
   set_gdbarch_push_dummy_call (gdbarch, m68hc11_push_dummy_call);
 
-  set_gdbarch_extract_return_value (gdbarch, m68hc11_extract_return_value);
-  set_gdbarch_return_value_on_stack (gdbarch, m68hc11_return_value_on_stack);
-
-  set_gdbarch_store_return_value (gdbarch, m68hc11_store_return_value);
-  set_gdbarch_deprecated_extract_struct_value_address (gdbarch, m68hc11_extract_struct_value_address);
-  set_gdbarch_use_struct_convention (gdbarch, m68hc11_use_struct_convention);
+  set_gdbarch_return_value (gdbarch, m68hc11_return_value);
   set_gdbarch_skip_prologue (gdbarch, m68hc11_skip_prologue);
   set_gdbarch_inner_than (gdbarch, core_addr_lessthan);
   set_gdbarch_breakpoint_from_pc (gdbarch, m68hc11_breakpoint_from_pc);
Index: values.c
===================================================================
RCS file: /cvs/src/src/gdb/values.c,v
retrieving revision 1.66
diff -p -u -r1.66 values.c
--- values.c	12 Jun 2004 18:02:30 -0000	1.66
+++ values.c	12 Jun 2004 19:22:05 -0000
@@ -1254,8 +1254,7 @@ using_struct_return (struct type *value_
 	 "struct return" vs "register return" conventions.  */
       if (code == TYPE_CODE_STRUCT
 	  || code == TYPE_CODE_UNION
-	  || code == TYPE_CODE_ARRAY
-	  || RETURN_VALUE_ON_STACK (value_type))
+	  || code == TYPE_CODE_ARRAY)
 	return USE_STRUCT_CONVENTION (gcc_p, value_type);
       else
 	return 0;
Index: doc/gdbint.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdbint.texinfo,v
retrieving revision 1.207
diff -p -u -r1.207 gdbint.texinfo
--- doc/gdbint.texinfo	9 Jun 2004 13:33:54 -0000	1.207
+++ doc/gdbint.texinfo	12 Jun 2004 19:22:20 -0000
@@ -3503,43 +3503,6 @@ form.
 Return the appropriate register set for a core file section with name
 @var{sect_name} and size @var{sect_size}.
 
-
-@item RETURN_VALUE_ON_STACK(@var{type})
-@findex RETURN_VALUE_ON_STACK
-@cindex returning structures by value
-@cindex structures, returning by value
-
-Return non-zero if values of type TYPE are returned on the stack, using
-the ``struct convention'' (i.e., the caller provides a pointer to a
-buffer in which the callee should store the return value).  This
-controls how the @samp{finish} command finds a function's return value,
-and whether an inferior function call reserves space on the stack for
-the return value.
-
-The full logic @value{GDBN} uses here is kind of odd.  
-
-@itemize @bullet
-@item
-If the type being returned by value is not a structure, union, or array,
-and @code{RETURN_VALUE_ON_STACK} returns zero, then @value{GDBN}
-concludes the value is not returned using the struct convention.
-
-@item
-Otherwise, @value{GDBN} calls @code{USE_STRUCT_CONVENTION} (see below).
-If that returns non-zero, @value{GDBN} assumes the struct convention is
-in use.
-@end itemize
-
-In other words, to indicate that a given type is returned by value using
-the struct convention, that type must be either a struct, union, array,
-or something @code{RETURN_VALUE_ON_STACK} likes, @emph{and} something
-that @code{USE_STRUCT_CONVENTION} likes.
-
-Note that, in C and C@t{++}, arrays are never returned by value.  In those
-languages, these predicates will always see a pointer type, never an
-array type.  All the references above to arrays being returned by value
-apply only to other languages.
-
 @item SOFTWARE_SINGLE_STEP_P()
 @findex SOFTWARE_SINGLE_STEP_P
 Define this as 1 if the target does not have a hardware single-step

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