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[RFA-v6] Handle cygwin wchar_t specifics
- From: "Pierre Muller" <pierre dot muller at ics-cnrs dot unistra dot fr>
- To: "'Pedro Alves'" <pedro at codesourcery dot com>, "'Tom Tromey'" <tromey at redhat dot com>
- Cc: <gdb-patches at sourceware dot org>
- Date: Thu, 21 Apr 2011 09:16:55 +0200
- Subject: [RFA-v6] Handle cygwin wchar_t specifics
- References: <5928.31498147479$1302882967@news.gmane.org> <m3wriq3zbu.fsf@fleche.redhat.com> <000201cbff30$e2266030$a6732090$@muller@ics-cnrs.unistra.fr> <201104202208.15956.pedro@codesourcery.com> <002c01cbfff1$53197690$f94c63b0$@muller@ics-cnrs.unistra.fr>
> > Didn't "extern" work?
>
> I didn't test it out before:
> it does work on my system, but is it
> sure it will compile and link correctly on
> all C compilers used for GDB?
>
> There is apparently no trace of your_gdb_wchar_t_is_bogus
> in my charset.o object file once it is made external.
>
> Could someone confirm that this will also compile
> on other C compiler used without creating link failures?
>
> I am perfectly willing to change this but it seemed
> to me to rely on some "obscure C compiler feature"
> (don't forget that I learned C to be able to support pascal
> language in GDB...).
I am stupid..
of course this works, otherwise each object would contain the
thousands of externals defined in all the loaded headers...
Here is a new version,
with both static to external switch for you_gdb_wchar_t_is_bogus
and Tom latest comments.
As it is not exactly what Tom asked me to change,
I resubmit it anyhow.
Pierre
PS: Should that be included in 7.3 branch?
2011-04-21 Pierre Muller <muller@ics.u-strasbg.fr>
* gdb_wchar.h (USE_INTERMEDIATE_ENCODING_FUNCTION): New macro.
(INTERMEDIATE_ENCODING): Change value to intermediate_encoding
function call if __STDC_ISO_10646__ macro is defined.
(intermediate_encoding): New prototype.
* charset.c (your_gdb_wchar_t_is_bogus): New extern test variable
to generate compile time error for unsupported gdb_wchar_t size.
(ENDIAN_SUFFIX): New macro.
(intermediate_encoding): New function.
Index: gdb_wchar.h
===================================================================
RCS file: /cvs/src/src/gdb/gdb_wchar.h,v
retrieving revision 1.6
diff -u -p -r1.6 gdb_wchar.h
--- gdb_wchar.h 1 Jan 2011 15:33:05 -0000 1.6
+++ gdb_wchar.h 21 Apr 2011 07:09:52 -0000
@@ -78,11 +78,10 @@ typedef wint_t gdb_wint_t;
iconv_open. We put the endianness into the encoding name to avoid
hosts that emit a BOM when the unadorned name is used. */
#if defined (__STDC_ISO_10646__)
-#if WORDS_BIGENDIAN
-#define INTERMEDIATE_ENCODING "UCS-4BE"
-#else
-#define INTERMEDIATE_ENCODING "UCS-4LE"
-#endif
+#define USE_INTERMEDIATE_ENCODING_FUNCTION
+#define INTERMEDIATE_ENCODING intermediate_encoding ()
+const char *intermediate_encoding (void);
+
#elif defined (_LIBICONV_VERSION) && _LIBICONV_VERSION >= 0x108
#define INTERMEDIATE_ENCODING "wchar_t"
#else
Index: charset.c
===================================================================
RCS file: /cvs/src/src/gdb/charset.c,v
retrieving revision 1.43
diff -u -p -r1.43 charset.c
--- charset.c 11 Jan 2011 15:10:01 -0000 1.43
+++ charset.c 21 Apr 2011 07:09:52 -0000
@@ -922,6 +922,70 @@ default_auto_wide_charset (void)
return GDB_DEFAULT_TARGET_WIDE_CHARSET;
}
+
+#ifdef USE_INTERMEDIATE_ENCODING_FUNCTION
+/* Macro used for UTF or UCS endianness suffix. */
+#if WORDS_BIGENDIAN
+#define ENDIAN_SUFFIX "BE"
+#else
+#define ENDIAN_SUFFIX "LE"
+#endif
+
+/* The code below serves to generate a compile time error if
+ gdb_wchar_t type is not of size 2 nor 4, despite the fact that
+ macro __STDC_ISO_10646__ is defined.
+ This is better than a gdb_assert call, because GDB cannot handle
+ strings correctly if this size is different. */
+
+extern char your_gdb_wchar_t_is_bogus[(sizeof (gdb_wchar_t) == 2
+ || sizeof (gdb_wchar_t) == 4)
+ ? 1 : -1];
+
+/* intermediate_encoding returns the charset unsed internally by
+ GDB to convert between target and host encodings. As the test above
+ compiled, sizeof (gdb_wchar_t) is either 2 or 4 bytes.
+ UTF-16/32 is tested first, UCS-2/4 is tested as a second option,
+ otherwise an error is generated. */
+
+const char *
+intermediate_encoding (void)
+{
+ iconv_t desc;
+ static const char *stored_result = NULL;
+ char *result;
+ int i;
+
+ if (stored_result)
+ return stored_result;
+ result = xstrprintf ("UTF-%d%s", sizeof (gdb_wchar_t) * 8,
ENDIAN_SUFFIX);
+ /* Check that the name is supported by iconv_open. */
+ desc = iconv_open (result, host_charset ());
+ if (desc != (iconv_t) -1)
+ {
+ iconv_close (desc);
+ stored_result = result;
+ return result;
+ }
+ /* Not valid, free the allocated memory. */
+ xfree (result);
+ /* Second try, with UCS-2 type. */
+ result = xstrprintf ("UCS-%d%s", sizeof (gdb_wchar_t), ENDIAN_SUFFIX);
+ /* Check that the name is supported by iconv_open. */
+ desc = iconv_open (result, host_charset ());
+ if (desc != (iconv_t) -1)
+ {
+ iconv_close (desc);
+ stored_result = result;
+ return result;
+ }
+ /* Not valid, free the allocated memory. */
+ xfree (result);
+ /* No valid charset found, generate error here. */
+ error (_("Unable to find a vaild charset for string conversions"));
+}
+
+#endif /* USE_INTERMEDIATE_ENCODING_FUNCTION */
+
void
_initialize_charset (void)
{