RTTI type improvement for (was: "Re: set print object on should affect MI varobjs (PR mi/13393)")

[xgsa <xgsa@yandex.ru>]

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> That change to value_rtti_indirect_type would be easier to read if it was
> a separate patch.

This is the first part of my previous patch that contains the change
to value_rtti_indirect_type. The second part requires this one to be
applied, so I'll provide it after commit.

Here is an example of what this patch fixes:
struct Base {
	virtual ~Base() {}
};

struct Derived: public Base {};

int main()
{
	Derived i;
	const Base& ri = i;
	const Base* pi = &i;
	return 0;   // <= run until this line
}

The "whatis ri" command fails with message:
  "Attempt to take contents of a non-pointer value.".
The "whatis pi" command does not respect cv-qualifiers:
  type = /* real type = Derived * */
  const Base *

This patch fixes these problems and takes into account the last Jan's review.


gdb/ChangeLog:

2012-01-06  Anton Gorenkov <xgsa@yandex.ru>

        * c-valprint.c (c_value_print): Use value_rtti_indirect_type
        instead of value_rtti_target_type.
        * eval.c (evaluate_subexp_standard): Use value_rtti_indirect_type
        instead of value_rtti_target_type.
        * typeprint.c (whatis_exp): Use value_rtti_indirect_type instead of
        value_rtti_target_type.
        * valops.c (value_ind): Extract function readjust_indirect_value_type.
        (value_rtti_indirect_type): The replacement for value_rtti_target_type.
        * value.c (readjust_indirect_value_type): New function.
        (coerce_ref): Support for enclosing type setting for references
        with readjust_indirect_value_type.
        * value.h (readjust_value_type): The replacement for
        value_rtti_target_type.



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diff --git a/gdb/c-valprint.c b/gdb/c-valprint.c
index 3461b08..e2e2792 100644
--- a/gdb/c-valprint.c
+++ b/gdb/c-valprint.c
@@ -698,22 +698,13 @@ c_value_print (struct value *val, struct ui_file *stream,
 
 	  if (value_entirely_available (val))
  	    {
-	      real_type = value_rtti_target_type (val, &full, &top, &using_enc);
+	      real_type = value_rtti_indirect_type (val, &full, &top,
+						    &using_enc);
 	      if (real_type)
 		{
 		  /* RTTI entry found.  */
-		  if (TYPE_CODE (type) == TYPE_CODE_PTR)
-		    {
-		      /* Create a pointer type pointing to the real
-			 type.  */
-		      type = lookup_pointer_type (real_type);
-		    }
-		  else
-		    {
-		      /* Create a reference type referencing the real
-			 type.  */
-		      type = lookup_reference_type (real_type);
-		    }
+		  type = real_type;
+
 		  /* Need to adjust pointer value.  */
 		  val = value_from_pointer (type, value_as_address (val) - top);
 
diff --git a/gdb/eval.c b/gdb/eval.c
index 5d758d1..10606a8 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1990,16 +1990,10 @@ evaluate_subexp_standard (struct type *expect_type,
         if (opts.objectprint && TYPE_TARGET_TYPE(type)
             && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
           {
-            real_type = value_rtti_target_type (arg1, &full, &top, &using_enc);
+            real_type = value_rtti_indirect_type (arg1, &full, &top,
+						  &using_enc);
             if (real_type)
-              {
-                if (TYPE_CODE (type) == TYPE_CODE_PTR)
-                  real_type = lookup_pointer_type (real_type);
-                else
-                  real_type = lookup_reference_type (real_type);
-
                 arg1 = value_cast (real_type, arg1);
-              }
           }
       }
 
diff --git a/gdb/typeprint.c b/gdb/typeprint.c
index cf4158d..6546c98 100644
--- a/gdb/typeprint.c
+++ b/gdb/typeprint.c
@@ -140,16 +140,7 @@ whatis_exp (char *exp, int show)
       if (((TYPE_CODE (type) == TYPE_CODE_PTR)
 	   || (TYPE_CODE (type) == TYPE_CODE_REF))
 	  && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
-        {
-          real_type = value_rtti_target_type (val, &full, &top, &using_enc);
-          if (real_type)
-            {
-              if (TYPE_CODE (type) == TYPE_CODE_PTR)
-                real_type = lookup_pointer_type (real_type);
-              else
-                real_type = lookup_reference_type (real_type);
-            }
-        }
+        real_type = value_rtti_indirect_type (val, &full, &top, &using_enc);
       else if (TYPE_CODE (type) == TYPE_CODE_CLASS)
 	real_type = value_rtti_type (val, &full, &top, &using_enc);
     }
diff --git a/gdb/valops.c b/gdb/valops.c
index cb39677..2bc02f3 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -1774,15 +1774,7 @@ value_ind (struct value *arg1)
 			      (value_as_address (arg1)
 			       - value_pointed_to_offset (arg1)));
 
-      /* Re-adjust type.  */
-      deprecated_set_value_type (arg2, TYPE_TARGET_TYPE (base_type));
-      /* Add embedding info.  */
-      set_value_enclosing_type (arg2, enc_type);
-      set_value_embedded_offset (arg2, value_pointed_to_offset (arg1));
-
-      /* We may be pointing to an object of some derived type.  */
-      arg2 = value_full_object (arg2, NULL, 0, 0, 0);
-      return arg2;
+      return readjust_indirect_value_type (arg2, enc_type, base_type, arg1);
     }
 
   error (_("Attempt to take contents of a non-pointer value."));
@@ -3528,21 +3520,48 @@ value_maybe_namespace_elt (const struct type *curtype,
   return result;
 }
 
-/* Given a pointer value V, find the real (RTTI) type of the object it
-   points to.
+/* Given a pointer or a reference value V, find its real (RTTI) type.
 
    Other parameters FULL, TOP, USING_ENC as with value_rtti_type()
    and refer to the values computed for the object pointed to.  */
 
 struct type *
-value_rtti_target_type (struct value *v, int *full, 
-			int *top, int *using_enc)
+value_rtti_indirect_type (struct value *v, int *full, 
+			  int *top, int *using_enc)
 {
   struct value *target;
+  struct type *type, *real_type, *target_type;
+
+  type = value_type (v);
+  type = check_typedef (type);
+  if (TYPE_CODE (type) == TYPE_CODE_REF)
+    target = coerce_ref (v);
+  else if (TYPE_CODE (type) == TYPE_CODE_PTR)
+    target = value_ind (v);
+  else
+    return NULL;
 
-  target = value_ind (v);
+  real_type = value_rtti_type (target, full, top, using_enc);
+
+  if (real_type)
+    {
+      /* Copy qualifiers to the referenced object.  */
+      target_type = value_type (target);
+      real_type = make_cv_type (TYPE_CONST (target_type),
+				TYPE_VOLATILE (target_type), real_type, NULL);
+      if (TYPE_CODE (type) == TYPE_CODE_REF)
+        real_type = lookup_reference_type (real_type);
+      else if (TYPE_CODE (type) == TYPE_CODE_PTR)
+        real_type = lookup_pointer_type (real_type);
+      else
+        internal_error (__FILE__, __LINE__, _("Unexpected value type."));
+
+      /* Copy qualifiers to the pointer/reference.  */
+      real_type = make_cv_type (TYPE_CONST (type), TYPE_VOLATILE (type),
+				real_type, NULL);
+    }
 
-  return value_rtti_type (target, full, top, using_enc);
+  return real_type;
 }
 
 /* Given a value pointed to by ARGP, check its real run-time type, and
diff --git a/gdb/value.c b/gdb/value.c
index d263d0c..c78e489 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -3109,11 +3109,30 @@ coerce_ref_if_computed (const struct value *arg)
   return funcs->coerce_ref (arg);
 }
 
+/* Look at value.h for description.  */
+
+struct value *
+readjust_indirect_value_type (struct value *value, struct type *enc_type,
+			      struct type *original_type,
+			      struct value *original_value)
+{
+  /* Re-adjust type.  */
+  deprecated_set_value_type (value, TYPE_TARGET_TYPE (original_type));
+
+  /* Add embedding info.  */
+  set_value_enclosing_type (value, enc_type);
+  set_value_embedded_offset (value, value_pointed_to_offset (original_value));
+
+  /* We may be pointing to an object of some derived type.  */
+  return value_full_object (value, NULL, 0, 0, 0);
+}
+
 struct value *
 coerce_ref (struct value *arg)
 {
   struct type *value_type_arg_tmp = check_typedef (value_type (arg));
   struct value *retval;
+  struct type *enc_type;
 
   retval = coerce_ref_if_computed (arg);
   if (retval)
@@ -3122,9 +3141,13 @@ coerce_ref (struct value *arg)
   if (TYPE_CODE (value_type_arg_tmp) != TYPE_CODE_REF)
     return arg;
 
-  return value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),
-			unpack_pointer (value_type (arg),
-					value_contents (arg)));
+  enc_type = check_typedef (value_enclosing_type (arg));
+  enc_type = TYPE_TARGET_TYPE (enc_type);
+
+  retval = value_at_lazy (enc_type,
+                          unpack_pointer (value_type (arg),
+                                          value_contents (arg)));
+  return readjust_indirect_value_type (retval, enc_type, value_type_arg_tmp, arg);
 }
 
 struct value *
diff --git a/gdb/value.h b/gdb/value.h
index d2c58ec..679192f 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -353,6 +353,19 @@ extern short *deprecated_value_regnum_hack (struct value *);
 
 extern struct value *coerce_ref_if_computed (const struct value *arg);
 
+/* Setup a new value type and enclosing value type for dereferenced value VALUE.
+   ENC_TYPE is the new enclosing type that should be set.  ORIGINAL_TYPE and
+   ORIGINAL_VALUE are the type and value of the original reference or pointer.
+
+   Note, that VALUE is modified by this function.
+
+   It is a common implementation for coerce_ref and value_ind.  */
+
+extern struct value *
+readjust_indirect_value_type (struct value *value, struct type *enc_type,
+			      struct type *original_type,
+			      struct value *original_value);
+
 /* Convert a REF to the object referenced.  */
 
 extern struct value *coerce_ref (struct value *value);
@@ -617,8 +630,8 @@ extern struct value *value_primitive_field (struct value *arg1, int offset,
 					    struct type *arg_type);
 
 
-extern struct type *value_rtti_target_type (struct value *, int *, int *,
-					    int *);
+extern struct type *value_rtti_indirect_type (struct value *, int *, int *,
+					      int *);
 
 extern struct value *value_full_object (struct value *, struct type *, int,
 					int, int);