Re: [RFA] print arrays with indexes

[Joel Brobecker <brobecker@adacore.com>]

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> This looks OK to me, with documentation and tests.  Minor comments:

Thanks for the review. The documentation has been submitted under:
        http://sources.redhat.com/ml/gdb-patches/2005-09/msg00240.html
And the testcase has been submitted under:
        http://sources.redhat.com/ml/gdb-patches/2005-09/msg00238.html

> - Reading the diff it's apparent that there is some space vs tabs
> confusion in the Ada changes.  I prefer tabs, but not violently so;
> however, I mostly prefer that code match its surroundings.  Otherwise
> indentation in diffs looks very odd.

Ok. There is some confusion, probably because I very much prefer spaces
(I am always jerked off by the cursor suddenly jumping because of
invisible tabs, it makes editing a bit more difficult, etc), but the
fact is that this is currently the policy. So I have forced tabs where
appropriate.

BTW: I think you are using vim, IIRC. Do you have some magic settings
that handles that handles the tabs for you. If I were able to have tabs
automatically created after I create spaces, and also transformed into
spaces when I backspace into them, as well as allowing me to go through
them as if they were spaces, I wouldn't mind the tabs so much.

> >  /*  Called by various <lang>_val_print routines to print elements of an
> >     array in the form "<elem1>, <elem2>, <elem3>, ...".
> >  
> > +   Some languages such as Ada allow the user to specify arrays where
> > +   the index of the first element is not zero. REAL_INDEX_OFFSET is
> > +   the user-level index of the first element of the array. For many
> > +   languages such as C or C++, it is always zero.
> > +
> 
> Ada is by no means the only language with this feature - namely,
> Fortran.  Can't you compute this value from the array type, instead
> of passing it in from Ada-specific code?  I couldn't see any obvious
> reasons why not.

I cannot either. So what I did was move that function to valprint.
I also removed the part computing the index type, it should be as
simple as using the TYPE_INDEX_TYPE macro, so no need to complexify
this function for that.

Note that this had the effect of losing the following code:

+  if (TYPE_CODE (index) == TYPE_CODE_RANGE)
+    index = TYPE_TARGET_TYPE (index);

which the function used to have. I couldn't understand why this
was necessary, and a look at where the type was used showed that
this was not necessary, as ada_print_scalar, the only eventual consumer
of that type, knew how to handle range types. I would think the same is
true of all other languages, right?

> > +/* Assuming TYPE is a simple, non-empty array type, compute the lower
> > +   bound and the array index type.  Save the low bound into LOW_BOUND
> > +   if not NULL.  Save the index type in INDEX_TYPE if not NULL.
> > +
> > +   Return 1 if the operation was successful. Return zero otherwise,
> > +   in which case the value of LOW_BOUND and INDEX_TYPE is undefined.  */
> 
> s/undefined/unmodified/, since you rely on it below.

Thanks for the recommendation. I really like this term better.

Here is a new patch, hopefully implementing the suggestions you made.

2005-09-22  Joel Brobecker  <brobecker@adacore.com>

        * language.h (language_defn): New field la_print_array_index.
        (LA_PRINT_ARRAY_INDEX): New macro.
        (default_print_array_index): Add declaration.
        * language.c (default_print_array_index): new function.
        (unknown_language): Add value for new field.
        (auto_language): Likewise.
        (local_language): Likewise.
        * ada-lang.c (ada_print_array_index): New function.
        (ada_language_defn): Add value for new field.
        * c-lang.c (c_language_defn): Likewise.
        (cpluc_language_defn): Likewise.
        (asm_language_defn): Likewise.
        (minimal_language_defn): Likewise.
        * f-lang.c (f_language_defn): Likewise.
        * jv-lang.c (java_language_defn): Likewise.
        * m2-lang.c (m2_language_defn): Likewise.
        * objc-lang.c (objc_language_defn): Likewise.
        * p-lang.c (pascal_language_defn): Likewise.
        * valprint.h (print_array_indexes_p): Add declaration.
        (get_array_low_bound): Add declaration.
        (maybe_print_array_index): Add declaration.
        * valprint.c (print_array_indexes): New static variable.
        (show_print_array_indexes): New function.
        (print_array_indexes_p): New function.
        (get_array_low_bound): New function.
        (maybe_print_array_index): New function.
        (val_print_array_elements): Print the index of each element if
        requested by the user.
        (_initialize_valprint): Add new array-indexes "set/show print" command.
        * ada-valprint.c (print_optional_low_bound): Replace extracted code
        by call to ada_get_array_low_bound_and_type(). Stop printing the low
        bound if indexes will be printed for all elements of the array.
        (val_print_packed_array_elements): Print the index of each element
        of the array if necessary.

Tested on x86-linux, no regression.

Thanks,
-- 
Joel

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Index: language.h
===================================================================
RCS file: /cvs/src/src/gdb/language.h,v
retrieving revision 1.35
diff -u -p -r1.35 language.h
--- language.h	9 May 2005 21:20:34 -0000	1.35
+++ language.h	27 Sep 2005 00:48:01 -0000
@@ -275,6 +275,12 @@ struct language_defn
     void (*la_language_arch_info) (struct gdbarch *,
 				   struct language_arch_info *);
 
+    /* Print the index of an element of an array.  */
+    void (*la_print_array_index) (struct value *index_value,
+                                  struct ui_file *stream,
+                                  int format,
+                                  enum val_prettyprint pretty);
+
     /* Add fields above this point, so the magic number is always last. */
     /* Magic number for compat checking */
 
@@ -362,6 +368,9 @@ extern enum language set_language (enum 
 #define LA_EMIT_CHAR(ch, stream, quoter) \
   (current_language->la_emitchar(ch, stream, quoter))
 
+#define LA_PRINT_ARRAY_INDEX(index_value, stream, format, pretty) \
+  (current_language->la_print_array_index(index_value, stream, format, pretty))
+
 /* Test a character to decide whether it can be printed in literal form
    or needs to be printed in another representation.  For example,
    in C the literal form of the character with octal value 141 is 'a'
@@ -457,4 +466,10 @@ extern char *language_class_name_from_ph
 /* Splitting strings into words.  */
 extern char *default_word_break_characters (void);
 
+/* Print the index of an array element using the C99 syntax.  */
+extern void default_print_array_index (struct value *index_value,
+                                       struct ui_file *stream,
+                                       int format,
+                                       enum val_prettyprint pretty);
+
 #endif /* defined (LANGUAGE_H) */
Index: language.c
===================================================================
RCS file: /cvs/src/src/gdb/language.c,v
retrieving revision 1.62
diff -u -p -r1.62 language.c
--- language.c	29 Aug 2005 12:57:49 -0000	1.62
+++ language.c	27 Sep 2005 00:48:02 -0000
@@ -1057,6 +1057,17 @@ default_word_break_characters (void)
   return " \t\n!@#$%^&*()+=|~`}{[]\"';:?/>.<,-";
 }
 
+/* Print the index of array elements using the C99 syntax.  */
+
+void
+default_print_array_index (struct value *index_value, struct ui_file *stream,
+                           int format, enum val_prettyprint pretty)
+{
+  fprintf_filtered (stream, "[");
+  LA_VALUE_PRINT (index_value, stream, format, pretty);
+  fprintf_filtered (stream, "] = ");
+}
+
 /* Define the language that is no language.  */
 
 static int
@@ -1181,6 +1192,7 @@ const struct language_defn unknown_langu
   NULL,
   default_word_break_characters,
   unknown_language_arch_info,	/* la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
@@ -1217,6 +1229,7 @@ const struct language_defn auto_language
   NULL,
   default_word_break_characters,
   unknown_language_arch_info,	/* la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
@@ -1252,6 +1265,7 @@ const struct language_defn local_languag
   NULL,
   default_word_break_characters,
   unknown_language_arch_info,	/* la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 \f
Index: ada-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-lang.c,v
retrieving revision 1.78
diff -u -p -r1.78 ada-lang.c
--- ada-lang.c	9 May 2005 21:20:29 -0000	1.78
+++ ada-lang.c	27 Sep 2005 00:48:07 -0000
@@ -303,6 +303,16 @@ ada_get_gdb_completer_word_break_charact
   return ada_completer_word_break_characters;
 }
 
+/* Print an array element index using the Ada syntax.  */
+
+static void
+ada_print_array_index (struct value *index_value, struct ui_file *stream,
+                       int format, enum val_prettyprint pretty)
+{
+  LA_VALUE_PRINT (index_value, stream, format, pretty);
+  fprintf_filtered (stream, " => ");
+}
+
 /* Read the string located at ADDR from the inferior and store the
    result into BUF.  */
 
@@ -8766,6 +8776,7 @@ const struct language_defn ada_language_
   NULL,
   ada_get_gdb_completer_word_break_characters,
   ada_language_arch_info,
+  ada_print_array_index,
   LANG_MAGIC
 };
 
Index: c-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/c-lang.c,v
retrieving revision 1.37
diff -u -p -r1.37 c-lang.c
--- c-lang.c	9 May 2005 21:20:30 -0000	1.37
+++ c-lang.c	27 Sep 2005 00:48:07 -0000
@@ -595,6 +595,7 @@ const struct language_defn c_language_de
   NULL,
   default_word_break_characters,
   c_language_arch_info,
+  default_print_array_index,
   LANG_MAGIC
 };
 
@@ -653,6 +654,7 @@ const struct language_defn cplus_languag
   &builtin_type_char,		/* Type of string elements */
   default_word_break_characters,
   NULL, /* FIXME: la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
@@ -688,6 +690,7 @@ const struct language_defn asm_language_
   NULL,
   default_word_break_characters,
   c_language_arch_info, /* FIXME: la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
@@ -728,6 +731,7 @@ const struct language_defn minimal_langu
   NULL,
   default_word_break_characters,
   c_language_arch_info,
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: f-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/f-lang.c,v
retrieving revision 1.31
diff -u -p -r1.31 f-lang.c
--- f-lang.c	9 May 2005 21:20:30 -0000	1.31
+++ f-lang.c	27 Sep 2005 00:48:08 -0000
@@ -485,6 +485,7 @@ const struct language_defn f_language_de
   &builtin_type_f_character,	/* Type of string elements */
   default_word_break_characters,
   NULL, /* FIXME: la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: jv-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/jv-lang.c,v
retrieving revision 1.42
diff -u -p -r1.42 jv-lang.c
--- jv-lang.c	27 May 2005 04:39:32 -0000	1.42
+++ jv-lang.c	27 Sep 2005 00:48:08 -0000
@@ -1114,6 +1114,7 @@ const struct language_defn java_language
   NULL,
   default_word_break_characters,
   c_language_arch_info,
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: m2-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/m2-lang.c,v
retrieving revision 1.23
diff -u -p -r1.23 m2-lang.c
--- m2-lang.c	9 May 2005 21:20:34 -0000	1.23
+++ m2-lang.c	27 Sep 2005 00:48:08 -0000
@@ -437,6 +437,7 @@ const struct language_defn m2_language_d
   &builtin_type_m2_char,	/* Type of string elements */
   default_word_break_characters,
   NULL, /* FIXME: la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: objc-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/objc-lang.c,v
retrieving revision 1.49
diff -u -p -r1.49 objc-lang.c
--- objc-lang.c	12 Jul 2005 12:11:44 -0000	1.49
+++ objc-lang.c	27 Sep 2005 00:48:10 -0000
@@ -684,6 +684,7 @@ const struct language_defn objc_language
   &builtin_type_char,		/* Type of string elements */
   default_word_break_characters,
   NULL, /* FIXME: la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: p-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/p-lang.c,v
retrieving revision 1.25
diff -u -p -r1.25 p-lang.c
--- p-lang.c	9 May 2005 21:20:34 -0000	1.25
+++ p-lang.c	27 Sep 2005 00:48:10 -0000
@@ -477,6 +477,7 @@ const struct language_defn pascal_langua
   &builtin_type_char,		/* Type of string elements */
   default_word_break_characters,
   NULL, /* FIXME: la_language_arch_info.  */
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: scm-lang.c
===================================================================
RCS file: /cvs/src/src/gdb/scm-lang.c,v
retrieving revision 1.32
diff -u -p -r1.32 scm-lang.c
--- scm-lang.c	27 May 2005 04:39:32 -0000	1.32
+++ scm-lang.c	27 Sep 2005 00:48:10 -0000
@@ -269,6 +269,7 @@ const struct language_defn scm_language_
   NULL,
   default_word_break_characters,
   c_language_arch_info,
+  default_print_array_index,
   LANG_MAGIC
 };
 
Index: valprint.h
===================================================================
RCS file: /cvs/src/src/gdb/valprint.h,v
retrieving revision 1.10
diff -u -p -r1.10 valprint.h
--- valprint.h	9 May 2005 21:20:35 -0000	1.10
+++ valprint.h	27 Sep 2005 00:48:10 -0000
@@ -50,6 +50,14 @@ extern int output_format;
 
 extern int stop_print_at_null;	/* Stop printing at null char? */
 
+extern int print_array_indexes_p (void);
+ 
+extern int get_array_low_bound (struct type *type, long *low_bound);
+
+extern void maybe_print_array_index (struct type *index_type, LONGEST index,
+                                     struct ui_file *stream, int format,
+                                     enum val_prettyprint pretty);
+
 extern void val_print_array_elements (struct type *, const gdb_byte *,
 				      CORE_ADDR, struct ui_file *, int,
 				      int, int, enum val_prettyprint,
Index: valprint.c
===================================================================
RCS file: /cvs/src/src/gdb/valprint.c,v
retrieving revision 1.54
diff -u -p -r1.54 valprint.c
--- valprint.c	10 Jun 2005 06:07:32 -0000	1.54
+++ valprint.c	27 Sep 2005 00:48:11 -0000
@@ -100,6 +100,17 @@ Default output radix for printing of val
 }
 int output_format = 0;
 
+/* By default we print arrays without printing the index of each element in
+   the array.  This behavior can be changed by setting PRINT_ARRAY_INDEXES.  */
+
+static int print_array_indexes = 0;
+static void
+show_print_array_indexes (struct ui_file *file, int from_tty,
+		          struct cmd_list_element *c, const char *value)
+{
+  fprintf_filtered (file, _("Printing of array indexes is %s.\n"), value);
+}
+
 /* Print repeat counts if there are more than this many repetitions of an
    element in an array.  Referenced by the low level language dependent
    print routines. */
@@ -859,6 +870,65 @@ print_char_chars (struct ui_file *stream
     }
 }
 
+/* Return non-zero if the debugger should print the index of each element
+   when printing array values.  */
+
+int
+print_array_indexes_p (void)
+{              
+  return print_array_indexes;
+} 
+
+/* Assuming TYPE is a simple, non-empty array type, compute its lower bound.
+   Save it into LOW_BOUND if not NULL.
+
+   Return 1 if the operation was successful. Return zero otherwise,
+   in which case the value of LOW_BOUND is unmodified.  */
+
+int
+get_array_low_bound (struct type *type, long *low_bound)
+{
+  struct type *index = TYPE_INDEX_TYPE (type);
+  long low = 0;
+                                  
+  if (index == NULL)
+    return 0;
+
+  if (TYPE_CODE (index) != TYPE_CODE_RANGE
+      && TYPE_CODE (index) != TYPE_CODE_ENUM)
+    return 0;
+
+  low = TYPE_LOW_BOUND (index);
+  if (low > TYPE_HIGH_BOUND (index))
+    return 0;
+
+  if (TYPE_CODE (index) == TYPE_CODE_RANGE)
+    index = TYPE_TARGET_TYPE (index);
+
+  if (low_bound)
+    *low_bound = low;
+
+  return 1;
+}
+                                       
+/* Print on STREAM using the given FORMAT the index for the element
+   at INDEX of an array whose index type is INDEX_TYPE.  */
+    
+void  
+maybe_print_array_index (struct type *index_type, LONGEST index,
+                         struct ui_file *stream, int format,
+                         enum val_prettyprint pretty)
+{
+  struct value *index_value;
+
+  if (!print_array_indexes)
+    return; 
+    
+  index_value = value_from_longest (index_type, index);
+
+  LA_PRINT_ARRAY_INDEX (index_value, stream, format, pretty);
+}   
+
 /*  Called by various <lang>_val_print routines to print elements of an
    array in the form "<elem1>, <elem2>, <elem3>, ...".
 
@@ -877,17 +947,25 @@ val_print_array_elements (struct type *t
 {
   unsigned int things_printed = 0;
   unsigned len;
-  struct type *elttype;
+  struct type *elttype, *index_type;
   unsigned eltlen;
   /* Position of the array element we are examining to see
      whether it is repeated.  */
   unsigned int rep1;
   /* Number of repetitions we have detected so far.  */
   unsigned int reps;
+  long low_bound_index;
+
+  if (!get_array_low_bound (type, &low_bound_index))
+    {
+      warning ("unable to get low bound of array, using zero as default");
+      low_bound_index = 0;
+    }
 
   elttype = TYPE_TARGET_TYPE (type);
   eltlen = TYPE_LENGTH (check_typedef (elttype));
   len = TYPE_LENGTH (type) / eltlen;
+  index_type = TYPE_INDEX_TYPE (type);
 
   annotate_array_section_begin (i, elttype);
 
@@ -906,6 +984,8 @@ val_print_array_elements (struct type *t
 	    }
 	}
       wrap_here (n_spaces (2 + 2 * recurse));
+      maybe_print_array_index (index_type, i + low_bound_index,
+                               stream, format, pretty);
 
       rep1 = i + 1;
       reps = 1;
@@ -1396,6 +1476,12 @@ Show the default input and output number
 Use 'show input-radix' or 'show output-radix' to independently show each."),
 	   &showlist);
 
+  add_setshow_boolean_cmd ("array-indexes", class_support,
+                           &print_array_indexes, _("\
+Set printing of array indexes."), _("\
+Show printing of array indexes"), NULL, NULL, show_print_array_indexes,
+                           &setprintlist, &showprintlist);
+
   /* Give people the defaults which they are used to.  */
   prettyprint_structs = 0;
   prettyprint_arrays = 0;
Index: ada-valprint.c
===================================================================
RCS file: /cvs/src/src/gdb/ada-valprint.c,v
retrieving revision 1.23
diff -u -p -r1.23 ada-valprint.c
--- ada-valprint.c	9 May 2005 21:20:30 -0000	1.23
+++ ada-valprint.c	27 Sep 2005 00:48:11 -0000
@@ -86,21 +86,14 @@ print_optional_low_bound (struct ui_file
   struct type *index_type;
   long low_bound;
 
-  index_type = TYPE_INDEX_TYPE (type);
-  low_bound = 0;
-
-  if (index_type == NULL)
+  if (print_array_indexes_p ())
     return 0;
-  if (TYPE_CODE (index_type) == TYPE_CODE_RANGE)
-    {
-      low_bound = TYPE_LOW_BOUND (index_type);
-      if (low_bound > TYPE_HIGH_BOUND (index_type))
-	return 0;
-      index_type = TYPE_TARGET_TYPE (index_type);
-    }
-  else
+
+  if (!get_array_low_bound (type, &low_bound))
     return 0;
 
+  index_type = TYPE_INDEX_TYPE (type);
+
   switch (TYPE_CODE (index_type))
     {
     case TYPE_CODE_ENUM:
@@ -137,16 +130,18 @@ val_print_packed_array_elements (struct 
   unsigned int i;
   unsigned int things_printed = 0;
   unsigned len;
-  struct type *elttype;
+  struct type *elttype, *index_type;
   unsigned eltlen;
   unsigned long bitsize = TYPE_FIELD_BITSIZE (type, 0);
   struct value *mark = value_mark ();
+  LONGEST low = 0;
 
   elttype = TYPE_TARGET_TYPE (type);
   eltlen = TYPE_LENGTH (check_typedef (elttype));
+  index_type = TYPE_INDEX_TYPE (type);
 
   {
-    LONGEST low, high;
+    LONGEST high;
     if (get_discrete_bounds (TYPE_FIELD_TYPE (type, 0), &low, &high) < 0)
       len = 1;
     else
@@ -174,6 +169,7 @@ val_print_packed_array_elements (struct 
 	    }
 	}
       wrap_here (n_spaces (2 + 2 * recurse));
+      maybe_print_array_index (index_type, i + low, stream, format, pretty);
 
       i0 = i;
       v0 = ada_value_primitive_packed_val (NULL, valaddr,
@@ -219,6 +215,8 @@ val_print_packed_array_elements (struct 
 		      fprintf_filtered (stream, ", ");
 		    }
 		  wrap_here (n_spaces (2 + 2 * recurse));
+		  maybe_print_array_index (index_type, j + low,
+					   stream, format, pretty);
 		}
 	      val_print (elttype, value_contents (v0), 0, 0, stream, format,
 			 0, recurse + 1, pretty);