RE: [RFC] Allow explicit 16 or 32 char in 'x /s'

Pierre Muller
2010-03-22T22:54:48Z

> -----Message d'origine-----
> De : gdb-patches-owner@sourceware.org [mailto:gdb-patches-
> owner@sourceware.org] De la part de Eli Zaretskii
> Envoyé : Friday, March 19, 2010 8:32 AM
> À : tromey@redhat.com
> Cc : pierre.muller@ics-cnrs.unistra.fr; gdb-patches@sourceware.org
> Objet : Re: [RFC] Allow explicit 16 or 32 char in 'x /s'
>
> > From: Tom Tromey <tromey@redhat.com>
> > Cc: <gdb-patches@sourceware.org>
> > Date: Thu, 18 Mar 2010 16:08:27 -0600
> >
> > I think the documentation should reflect that the user can't choose
> the
> > encoding used here.
>
> I agree. It should also say which encoding is used by GDB in this
> case.

Not that I do not agree with you, but I would like to
stress that how the string is displayed also depend on the current language,
so that, for C or any other language using c_printstr function,
/hs will use UTF-16LE or UTF-16BE according to current gdbarch endianess.
/ws will use UTF-32LE or UTF-32BE.

But I don't know exactly for other languages and I would like to be sure
about
what you want me to add to the docs...
Furthermore if you look into charset_for_string_type
function in c-lang.c source, you will see that there are two FIXME
just right at the position of these charset name settings.

To answer Tom's concern about the change in classify_type function,
I modified my patch to change the elttype in do_examine to match exactly
what is expected by charset_for_string_type function.
Thus this new version has no modification in c-lang.c file.

I also added a very basic check for string display using 'x /hs' and 'x
/ws'.

Pierre Muller

2010-03-22 Pierre Muller <muller@ics.u-strasbg.fr>

* printcmd.c (decode_format): Set char size to byte
for strings unless explicit size is given.
(print_formatted): Correct calculation of NEXT_ADDRESS
for 16 or 32 bit strings.
(do_examine): Do not force byte size for strings.
Use 'char16_t' and 'char32_t' types to allow
for correct recognition in classify_type.

2010-03-22 Pierre Muller <muller@ics.u-strasbg.fr>

* gdb.base/charset.c (Strin16, String32): New variables.
* gdb.base/charset.exp (gdb_test): Test correct display
of 16 or 32 bit strings.

Index: printcmd.c
===================================================================
RCS file: /cvs/src/src/gdb/printcmd.c,v
retrieving revision 1.173
diff -u -p -r1.173 printcmd.c
--- printcmd.c 5 Mar 2010 20:18:14 -0000 1.173
+++ printcmd.c 22 Mar 2010 22:25:34 -0000
@@ -260,6 +260,11 @@ decode_format (char **string_ptr, int of
/* Characters default to one byte. */
val.size = osize ? 'b' : osize;
break;
+ case 's':
+ /* Display strings with byte size chars unless explicitly specified.
*/
+ val.size = 'b';
+ break;
+
default:
/* The default is the size most recently specified. */
val.size = osize;
@@ -295,7 +300,7 @@ print_formatted (struct value *val, int
next_address = (value_address (val)
+ val_print_string (elttype,
value_address (val), -1,
- stream, options));
+ stream, options) * len);
}
return;

@@ -802,9 +807,11 @@ do_examine (struct format_data fmt, stru
next_gdbarch = gdbarch;
next_address = addr;

- /* String or instruction format implies fetch single bytes
- regardless of the specified size. */
- if (format == 's' || format == 'i')
+ /* Instruction format implies fetch single bytes
+ regardless of the specified size.
+ The case of strings is handled n decode_format, only explicit
+ size operator are not changed to 'b'. */
+ if (format == 'i')
size = 'b';

if (size == 'a')
@@ -831,6 +838,36 @@ do_examine (struct format_data fmt, stru
else if (size == 'g')
val_type = builtin_type (next_gdbarch)->builtin_int64;

+ if (format == 's')
+ {
+ struct type *char_type;
+ if (size == 'h')
+ {
+ char_type = lookup_typename (current_language, next_gdbarch,
+ "char16_t", NULL, 1);
+ if (!char_type)
+ char_type = arch_type (next_gdbarch, TYPE_CODE_INT, 2,
"char16_t");
+ check_typedef (char_type);
+ if (TYPE_LENGTH (char_type) == 2)
+ val_type = char_type;
+ }
+ else if (size == 'w')
+ {
+ char_type = lookup_typename (current_language, next_gdbarch,
+ "char32_t", NULL, 1);
+ if (!char_type)
+ char_type = arch_type (next_gdbarch, TYPE_CODE_INT, 4,
"char32_t");
+ check_typedef (char_type);
+ if (char_type && TYPE_LENGTH (char_type) == 4)
+ val_type = char_type;
+ }
+ else
+ {
+ size = 'b';
+ val_type = builtin_type (next_gdbarch)->builtin_int8;
+ }
+ }
+
maxelts = 8;
if (size == 'w')
maxelts = 4;
Index: testsuite/gdb.base/charset.c
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.base/charset.c,v
retrieving revision 1.12
diff -u -p -r1.12 charset.c
--- testsuite/gdb.base/charset.c 1 Jan 2010 07:32:00 -0000 1.12
+++ testsuite/gdb.base/charset.c 22 Mar 2010 22:25:34 -0000
@@ -65,6 +65,9 @@ typedef unsigned int char32_t;
char16_t uvar;
char32_t Uvar;

+char16_t *String16;
+char32_t *String32;
+
/* A typedef to a typedef should also work. */
typedef wchar_t my_wchar_t;
my_wchar_t myvar;
Index: testsuite/gdb.base/charset.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.base/charset.exp,v
retrieving revision 1.21
diff -u -p -r1.21 charset.exp
--- testsuite/gdb.base/charset.exp 17 Feb 2010 22:05:58 -0000 1.21
+++ testsuite/gdb.base/charset.exp 22 Mar 2010 22:25:35 -0000
@@ -616,4 +616,21 @@ gdb_test "print 'a' == 'a' || 'b' == 'b'
".* = 1" \
"EVAL_SKIP cleanup handling regression test"

+
+proc string_display { var_name set_prefix x_size x_type} {
+ gdb_test "set ${var_name} = ${set_prefix}\"Test String\\0with zeroes\""
"" "Assign ${var_name} with prefix ${set_prefix}"
+ gdb_test "x /2${x_size}s ${var_name}" ".* ${x_type}\"Test
String\"\[\r\n\]+.* ${x_type}\"with zeroes\"" "Display String ${var_name}
with x/${x_size}s"
+}
+
+string_display String16 u h u
+if {$wchar_size == 2} {
+ string_display String16 L h u
+}
+
+string_display String32 U w U
+if {$wchar_size == 4} {
+ string_display String32 L w U
+}
+
+
gdb_exit