Re: -var-info-path-expression

[Vladimir Prus <vladimir at codesourcery dot com>]

On Tuesday 03 July 2007 21:13, Daniel Jacobowitz wrote:
> On Mon, Jun 18, 2007 at 02:42:59PM +0400, Vladimir Prus wrote:
> > 
> > The attached patch is a revised, and updated for mainline,
> > version of my earlier patch to add -var-info-path-expression.
> > The review of the previous version is at:
> > 
> > 	http://article.gmane.org/gmane.comp.gdb.patches/32582
> > 
> > and asks for: 
> > 
> > 	1. _() in some places.
> > 	2. Not using of name of gdb function in mi error messages
> > 	3. Points that path_expr != NULL implies it's not a root
> > 	varobj.
> > 
> > Those changes were made.
> 
> Is this the right version of the patch?  I was going to say it was OK,
> with documentation, and a few small changes - but that's the list of
> small changes above.  

Oops. I've forgotten to commit said changes to my local repo, from
where patches are generated. Here's updated patch.

> Anyway, other than that and some comment formatting, it looks fine to me.

What kind of formatting? Do you think you can indicate what to fix so that
I can fix it on my own without you pinpointing every problem. Two spaces again,
or something else?

- Volodya

--- gdb/mi/mi-cmds.h	(/mirrors/gdb_mainline)	(revision 4330)
+++ gdb/mi/mi-cmds.h	(/patches/gdb/path_expression/gdb_mainline)	(revision 4330)
@@ -109,6 +109,7 @@ extern mi_cmd_argv_ftype mi_cmd_var_crea
 extern mi_cmd_argv_ftype mi_cmd_var_delete;
 extern mi_cmd_argv_ftype mi_cmd_var_evaluate_expression;
 extern mi_cmd_argv_ftype mi_cmd_var_info_expression;
+extern mi_cmd_argv_ftype mi_cmd_var_info_path_expression;
 extern mi_cmd_argv_ftype mi_cmd_var_info_num_children;
 extern mi_cmd_argv_ftype mi_cmd_var_info_type;
 extern mi_cmd_argv_ftype mi_cmd_var_list_children;
--- gdb/mi/mi-cmds.c	(/mirrors/gdb_mainline)	(revision 4330)
+++ gdb/mi/mi-cmds.c	(/patches/gdb/path_expression/gdb_mainline)	(revision 4330)
@@ -151,6 +151,8 @@ struct mi_cmd mi_cmds[] =
   { "var-create", { NULL, 0 }, 0, mi_cmd_var_create},
   { "var-delete", { NULL, 0 }, 0, mi_cmd_var_delete},
   { "var-evaluate-expression", { NULL, 0 }, 0, mi_cmd_var_evaluate_expression},
+  { "var-info-path-expression", { NULL, 0 }, 0, 
+    mi_cmd_var_info_path_expression},
   { "var-info-expression", { NULL, 0 }, 0, mi_cmd_var_info_expression},
   { "var-info-num-children", { NULL, 0 }, 0, mi_cmd_var_info_num_children},
   { "var-info-type", { NULL, 0 }, 0, mi_cmd_var_info_type},
--- gdb/mi/mi-cmd-var.c	(/mirrors/gdb_mainline)	(revision 4330)
+++ gdb/mi/mi-cmd-var.c	(/patches/gdb/path_expression/gdb_mainline)	(revision 4330)
@@ -413,6 +413,27 @@ mi_cmd_var_info_type (char *command, cha
 }
 
 enum mi_cmd_result
+mi_cmd_var_info_path_expression (char *command, char **argv, int argc)
+{
+  struct varobj *var;
+  char *path_expr;
+
+  if (argc != 1)
+    error (_("Usage: NAME."));
+
+  /* Get varobj handle, if a valid var obj name was specified */
+  var = varobj_get_handle (argv[0]);
+  if (var == NULL)
+    error (_("Variable object not found"));
+  
+  path_expr = varobj_get_path_expr (var);
+
+  ui_out_field_string (uiout, "path_expr", path_expr);
+
+  return MI_CMD_DONE;
+}
+
+enum mi_cmd_result
 mi_cmd_var_info_expression (char *command, char **argv, int argc)
 {
   enum varobj_languages lang;
--- gdb/varobj.c	(/mirrors/gdb_mainline)	(revision 4330)
+++ gdb/varobj.c	(/patches/gdb/path_expression/gdb_mainline)	(revision 4330)
@@ -101,6 +101,10 @@ struct varobj
   /* NOTE: This is the "expression" */
   char *name;
 
+  /* Alloc'd expression for this child.  Can be used to create a
+     root variable corresponding to this child. */
+  char *path_expr;
+
   /* The alloc'd name for this variable's object. This is here for
      convenience when constructing this object's children. */
   char *obj_name;
@@ -236,6 +240,8 @@ static char *c_name_of_variable (struct 
 
 static char *c_name_of_child (struct varobj *parent, int index);
 
+static char *c_path_expr_of_child (struct varobj *child);
+
 static struct value *c_value_of_root (struct varobj **var_handle);
 
 static struct value *c_value_of_child (struct varobj *parent, int index);
@@ -256,6 +262,8 @@ static char *cplus_name_of_variable (str
 
 static char *cplus_name_of_child (struct varobj *parent, int index);
 
+static char *cplus_path_expr_of_child (struct varobj *child);
+
 static struct value *cplus_value_of_root (struct varobj **var_handle);
 
 static struct value *cplus_value_of_child (struct varobj *parent, int index);
@@ -274,6 +282,8 @@ static char *java_name_of_variable (stru
 
 static char *java_name_of_child (struct varobj *parent, int index);
 
+static char *java_path_expr_of_child (struct varobj *child);
+
 static struct value *java_value_of_root (struct varobj **var_handle);
 
 static struct value *java_value_of_child (struct varobj *parent, int index);
@@ -301,6 +311,10 @@ struct language_specific
   /* The name of the INDEX'th child of PARENT. */
   char *(*name_of_child) (struct varobj * parent, int index);
 
+  /* Returns the rooted expression of CHILD, which is a variable
+     obtain that has some parent.  */
+  char *(*path_expr_of_child) (struct varobj * child);
+
   /* The ``struct value *'' of the root variable ROOT. */
   struct value *(*value_of_root) (struct varobj ** root_handle);
 
@@ -325,6 +339,7 @@ static struct language_specific language
    c_number_of_children,
    c_name_of_variable,
    c_name_of_child,
+   c_path_expr_of_child,
    c_value_of_root,
    c_value_of_child,
    c_type_of_child,
@@ -337,6 +352,7 @@ static struct language_specific language
    c_number_of_children,
    c_name_of_variable,
    c_name_of_child,
+   c_path_expr_of_child,
    c_value_of_root,
    c_value_of_child,
    c_type_of_child,
@@ -349,6 +365,7 @@ static struct language_specific language
    cplus_number_of_children,
    cplus_name_of_variable,
    cplus_name_of_child,
+   cplus_path_expr_of_child,
    cplus_value_of_root,
    cplus_value_of_child,
    cplus_type_of_child,
@@ -361,6 +378,7 @@ static struct language_specific language
    java_number_of_children,
    java_name_of_variable,
    java_name_of_child,
+   java_path_expr_of_child,
    java_value_of_root,
    java_value_of_child,
    java_type_of_child,
@@ -444,6 +462,7 @@ varobj_create (char *objname,
       char *p;
       enum varobj_languages lang;
       struct value *value = NULL;
+      int expr_len;
 
       /* Parse and evaluate the expression, filling in as much
          of the variable's data as possible */
@@ -488,7 +507,10 @@ varobj_create (char *objname,
 
       var->format = variable_default_display (var);
       var->root->valid_block = innermost_block;
-      var->name = savestring (expression, strlen (expression));
+      expr_len = strlen (expression);
+      var->name = savestring (expression, expr_len);
+      /* For a root var, the name and the expr are the same.  */
+      var->path_expr = savestring (expression, expr_len);
 
       /* When the frame is different from the current frame, 
          we must select the appropriate frame before parsing
@@ -806,6 +828,23 @@ varobj_get_gdb_type (struct varobj *var)
   return var->type;
 }
 
+/* Return a pointer to the full rooted expression of varobj VAR.
+   If it has not been computed yet, compute it */
+char *
+varobj_get_path_expr (struct varobj *var)
+{
+  if (var->path_expr != NULL)
+    return var->path_expr;
+  else 
+    {
+      /* For root varobjs, we initialize path_expr
+	 when creating varobj, so here it should be
+	 child varobj.  */
+      gdb_assert (!is_root_p (var));
+      return (*var->root->lang->path_expr_of_child) (var);
+    }
+}
+
 enum varobj_languages
 varobj_get_language (struct varobj *var)
 {
@@ -1459,6 +1498,7 @@ new_variable (void)
 
   var = (struct varobj *) xmalloc (sizeof (struct varobj));
   var->name = NULL;
+  var->path_expr = NULL;
   var->obj_name = NULL;
   var->index = -1;
   var->type = NULL;
@@ -1507,6 +1547,7 @@ free_variable (struct varobj *var)
   xfree (var->name);
   xfree (var->obj_name);
   xfree (var->print_value);
+  xfree (var->path_expr);
   xfree (var);
 }
 
@@ -1844,13 +1885,21 @@ varobj_value_is_changeable_p (struct var
    Both TYPE and *TYPE should be non-null. VALUE
    can be null if we want to only translate type.
    *VALUE can be null as well -- if the parent
-   value is not known.  */
+   value is not known.  
+
+   If WAS_PTR is not NULL, set *WAS_PTR to 0 or 1
+   depending on whether pointer was deferenced
+   in this function.  */
 static void
 adjust_value_for_child_access (struct value **value,
-				  struct type **type)
+				  struct type **type,
+				  int *was_ptr)
 {
   gdb_assert (type && *type);
 
+  if (was_ptr)
+    *was_ptr = 0;
+
   *type = check_typedef (*type);
   
   /* The type of value stored in varobj, that is passed
@@ -1871,6 +1920,8 @@ adjust_value_for_child_access (struct va
 	  if (value && *value)
 	    gdb_value_ind (*value, value);	  
 	  *type = target_type;
+	  if (was_ptr)
+	    *was_ptr = 1;
 	}
     }
 
@@ -1887,7 +1938,7 @@ c_number_of_children (struct varobj *var
   int children = 0;
   struct type *target;
 
-  adjust_value_for_child_access (NULL, &type);
+  adjust_value_for_child_access (NULL, &type, NULL);
   target = get_target_type (type);
 
   switch (TYPE_CODE (type))
@@ -1983,10 +2034,13 @@ value_struct_element_index (struct value
    to NULL.  */
 static void 
 c_describe_child (struct varobj *parent, int index,
-		  char **cname, struct value **cvalue, struct type **ctype)
+		  char **cname, struct value **cvalue, struct type **ctype,
+		  char **cfull_expression)
 {
   struct value *value = parent->value;
   struct type *type = get_value_type (parent);
+  char *parent_expression = NULL;
+  int was_ptr;
 
   if (cname)
     *cname = NULL;
@@ -1994,8 +2048,12 @@ c_describe_child (struct varobj *parent,
     *cvalue = NULL;
   if (ctype)
     *ctype = NULL;
-
-  adjust_value_for_child_access (&value, &type);
+  if (cfull_expression)
+    {
+      *cfull_expression = NULL;
+      parent_expression = varobj_get_path_expr (parent);
+    }
+  adjust_value_for_child_access (&value, &type, &was_ptr);
       
   switch (TYPE_CODE (type))
     {
@@ -2015,6 +2073,12 @@ c_describe_child (struct varobj *parent,
       if (ctype)
 	*ctype = get_target_type (type);
 
+      if (cfull_expression)
+	*cfull_expression = xstrprintf ("(%s)[%d]", parent_expression, 
+					index
+					+ TYPE_LOW_BOUND (TYPE_INDEX_TYPE (type)));
+
+
       break;
 
     case TYPE_CODE_STRUCT:
@@ -2034,6 +2098,13 @@ c_describe_child (struct varobj *parent,
       if (ctype)
 	*ctype = TYPE_FIELD_TYPE (type, index);
 
+      if (cfull_expression)
+	{
+	  char *join = was_ptr ? "->" : ".";
+	  *cfull_expression = xstrprintf ("(%s)%s%s", parent_expression, join,
+					  TYPE_FIELD_NAME (type, index));
+	}
+
       break;
 
     case TYPE_CODE_PTR:
@@ -2048,6 +2119,9 @@ c_describe_child (struct varobj *parent,
 	 declared type of the variable.  */
       if (ctype)
 	*ctype = TYPE_TARGET_TYPE (type);
+
+      if (cfull_expression)
+	*cfull_expression = xstrprintf ("*(%s)", parent_expression);
       
       break;
 
@@ -2055,6 +2129,8 @@ c_describe_child (struct varobj *parent,
       /* This should not happen */
       if (cname)
 	*cname = xstrdup ("???");
+      if (cfull_expression)
+	*cfull_expression = xstrdup ("???");
       /* Don't set value and type, we don't know then. */
     }
 }
@@ -2063,10 +2139,18 @@ static char *
 c_name_of_child (struct varobj *parent, int index)
 {
   char *name;
-  c_describe_child (parent, index, &name, NULL, NULL);
+  c_describe_child (parent, index, &name, NULL, NULL, NULL);
   return name;
 }
 
+static char *
+c_path_expr_of_child (struct varobj *child)
+{
+  c_describe_child (child->parent, child->index, NULL, NULL, NULL, 
+		    &child->path_expr);
+  return child->path_expr;
+}
+
 static struct value *
 c_value_of_root (struct varobj **var_handle)
 {
@@ -2115,7 +2199,7 @@ static struct value *
 c_value_of_child (struct varobj *parent, int index)
 {
   struct value *value = NULL;
-  c_describe_child (parent, index, NULL, &value, NULL);
+  c_describe_child (parent, index, NULL, &value, NULL, NULL);
 
   return value;
 }
@@ -2124,7 +2208,7 @@ static struct type *
 c_type_of_child (struct varobj *parent, int index)
 {
   struct type *type = NULL;
-  c_describe_child (parent, index, NULL, NULL, &type);
+  c_describe_child (parent, index, NULL, NULL, &type, NULL);
   return type;
 }
 
@@ -2214,7 +2298,7 @@ cplus_number_of_children (struct varobj 
   if (!CPLUS_FAKE_CHILD (var))
     {
       type = get_value_type (var);
-      adjust_value_for_child_access (NULL, &type);
+      adjust_value_for_child_access (NULL, &type, NULL);
 
       if (((TYPE_CODE (type)) == TYPE_CODE_STRUCT) ||
 	  ((TYPE_CODE (type)) == TYPE_CODE_UNION))
@@ -2241,7 +2325,7 @@ cplus_number_of_children (struct varobj 
       int kids[3];
 
       type = get_value_type (var->parent);
-      adjust_value_for_child_access (NULL, &type);
+      adjust_value_for_child_access (NULL, &type, NULL);
 
       cplus_class_num_children (type, kids);
       if (strcmp (var->name, "public") == 0)
@@ -2312,11 +2396,14 @@ match_accessibility (struct type *type, 
 
 static void
 cplus_describe_child (struct varobj *parent, int index,
-		      char **cname, struct value **cvalue, struct type **ctype)
+		      char **cname, struct value **cvalue, struct type **ctype,
+		      char **cfull_expression)
 {
   char *name = 0;
   struct value *value;
   struct type *type;
+  int was_ptr;
+  char *parent_expression = NULL;
 
   if (cname)
     *cname = NULL;
@@ -2324,24 +2411,30 @@ cplus_describe_child (struct varobj *par
     *cvalue = NULL;
   if (ctype)
     *ctype = NULL;
-
+  if (cfull_expression)
+    *cfull_expression = NULL;
 
   if (CPLUS_FAKE_CHILD (parent))
     {
       value = parent->parent->value;
       type = get_value_type (parent->parent);
+      if (cfull_expression)
+	parent_expression = varobj_get_path_expr (parent->parent);
     }
   else
     {
       value = parent->value;
       type = get_value_type (parent);
+      if (cfull_expression)
+	parent_expression = varobj_get_path_expr (parent);
     }
 
-  adjust_value_for_child_access (&value, &type);
+  adjust_value_for_child_access (&value, &type, &was_ptr);
 
   if (TYPE_CODE (type) == TYPE_CODE_STRUCT
       || TYPE_CODE (type) == TYPE_CODE_STRUCT)
     {
+      char *join = was_ptr ? "->" : ".";
       if (CPLUS_FAKE_CHILD (parent))
 	{
 	  /* The fields of the class type are ordered as they
@@ -2376,6 +2469,11 @@ cplus_describe_child (struct varobj *par
 
 	  if (ctype)
 	    *ctype = TYPE_FIELD_TYPE (type, type_index);
+
+	  if (cfull_expression)
+	    *cfull_expression = xstrprintf ("((%s)%s%s)", parent_expression,
+					    join, 
+					    TYPE_FIELD_NAME (type, type_index));
 	}
       else if (index < TYPE_N_BASECLASSES (type))
 	{
@@ -2386,12 +2484,22 @@ cplus_describe_child (struct varobj *par
 	  if (cvalue && value)
 	    {
 	      *cvalue = value_cast (TYPE_FIELD_TYPE (type, index), value);
+	      release_value (*cvalue);
 	    }
 
 	  if (ctype)
 	    {
 	      *ctype = TYPE_FIELD_TYPE (type, index);
 	    }
+
+	  if (cfull_expression)
+	    {
+	      char *ptr = was_ptr ? " *" : "";
+	      *cfull_expression = xstrprintf ("((%s%s) %s)", 
+					      TYPE_FIELD_NAME (type, index),
+					      ptr,
+					      parent_expression);
+	    }
 	}
       else
 	{
@@ -2438,12 +2546,12 @@ cplus_describe_child (struct varobj *par
 	  if (cname)
 	    *cname = xstrdup (access);
 
-	  /* Value and type are null here.  */
+	  /* Value and type and full expression are null here.  */
 	}
     }
   else
     {
-      c_describe_child (parent, index, cname, cvalue, ctype);
+      c_describe_child (parent, index, cname, cvalue, ctype, cfull_expression);
     }  
 }
 
@@ -2451,10 +2559,18 @@ static char *
 cplus_name_of_child (struct varobj *parent, int index)
 {
   char *name = NULL;
-  cplus_describe_child (parent, index, &name, NULL, NULL);
+  cplus_describe_child (parent, index, &name, NULL, NULL, NULL);
   return name;
 }
 
+static char *
+cplus_path_expr_of_child (struct varobj *child)
+{
+  cplus_describe_child (child->parent, child->index, NULL, NULL, NULL, 
+			&child->path_expr);
+  return child->path_expr;
+}
+
 static struct value *
 cplus_value_of_root (struct varobj **var_handle)
 {
@@ -2465,7 +2581,7 @@ static struct value *
 cplus_value_of_child (struct varobj *parent, int index)
 {
   struct value *value = NULL;
-  cplus_describe_child (parent, index, NULL, &value, NULL);
+  cplus_describe_child (parent, index, NULL, &value, NULL, NULL);
   return value;
 }
 
@@ -2473,7 +2589,7 @@ static struct type *
 cplus_type_of_child (struct varobj *parent, int index)
 {
   struct type *type = NULL;
-  cplus_describe_child (parent, index, NULL, NULL, &type);
+  cplus_describe_child (parent, index, NULL, NULL, &type, NULL);
   return type;
 }
 
@@ -2545,6 +2661,12 @@ java_name_of_child (struct varobj *paren
   return name;
 }
 
+static char *
+java_path_expr_of_child (struct varobj *child)
+{
+  return NULL;
+}
+
 static struct value *
 java_value_of_root (struct varobj **var_handle)
 {
--- gdb/varobj.h	(/mirrors/gdb_mainline)	(revision 4330)
+++ gdb/varobj.h	(/patches/gdb/path_expression/gdb_mainline)	(revision 4330)
@@ -99,6 +99,8 @@ extern char *varobj_get_type (struct var
 
 extern struct type *varobj_get_gdb_type (struct varobj *var);
 
+extern char *varobj_get_path_expr (struct varobj *var);
+
 extern enum varobj_languages varobj_get_language (struct varobj *var);
 
 extern int varobj_get_attributes (struct varobj *var);

Property changes on: 
___________________________________________________________________
Name: csl:base
 +/all/patches/gdb/path_4_unify_cpp/gdb_mainline
Name: svk:merge
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/path_1/gdb_mainline:3166
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/path_2_children/gdb_mainline:3167
 +
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/path_3_5_references/gdb_mainline:3213
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/path_3_unify/gdb_mainline:3168
 +
 +d48a11ec-ee1c-0410-b3f5-c20844f99675:/patches/gdb/path_4_unify_cpp/gdb_mainline:3214
 +e7755896-6108-0410-9592-8049d3e74e28:/mirrors/gdb/trunk:174259