Re: Your INTERMEDIATE_ENCODING patch for Solaris

[Tom Tromey <tromey@redhat.com>]

>>>>> "Pierre" == Pierre Muller <pierre.muller@ics-cnrs.unistra.fr> writes:

Pierre> Upon further investigation, I must confess that the OpenSolaris 
Pierre> situation is a real mess:

Pierre>   I get a working libiconv version for x86_64 solaris
Pierre> using CSW libiconv version 0x10D,

From the version number, I guess this is GNU libiconv.
What happens if you don't build with libiconv, but rely instead on the
iconv in the Solaris libc?

Pierre> libiconv_open with parameter 'wchar_t' and 'UTF-8' works.
Pierre> but on my Sparc64 test machine, libiconv is
Pierre> on /usr/local/lib and its version is 0x10B.
Pierre> This later version fails on calls to libiconv_open
Pierre> with 'wchar_t' and 'ASCII'.

Ouch, but ok.  We can check _LIBICONV_VERSION >= 0x10D.
This actually simplifies the patch a little; I didn't know about
_LIBICONV_VERSION before.

Could you try this?  I also fixed the INTERMEDIATE_ENCODING problem you
pointed out.

Tom

2010-08-17  Tom Tromey  <tromey@redhat.com>

	* gdb_wchar.h: Check _LIBICONV_VERSION, __STDC_ISO_10646__.
	Change how INTERMEDIATE_ENCODING is defined.

diff --git a/gdb/gdb_wchar.h b/gdb/gdb_wchar.h
index fca3fe4..78f59a1 100644
--- a/gdb/gdb_wchar.h
+++ b/gdb/gdb_wchar.h
@@ -23,7 +23,11 @@
    
    Capable systems have the full suite: wchar_t support and iconv
    (perhaps via GNU libiconv).  On these machines, full functionality
-   is available.
+   is available.  Note that full functionality is dependent on us
+   being able to convert from an arbitrary encoding to wchar_t.  In
+   practice this means we look for __STDC_ISO_10646__ (where we know
+   the name of the wchar_t encoding) or GNU libiconv, where we can use
+   "wchar_t".
    
    DJGPP is known to have libiconv but not wchar_t support.  On
    systems like this, we use the narrow character functions.  The full
@@ -35,8 +39,6 @@
    wrappers for the wchar_t functionality we use.  */
 
 
-#define INTERMEDIATE_ENCODING "wchar_t"
-
 #if defined (HAVE_ICONV)
 #include <iconv.h>
 #else
@@ -45,9 +47,15 @@
 #define PHONY_ICONV
 #endif
 
-/* We use "btowc" as a sentinel to detect functioning wchar_t
-   support.  */
-#if defined (HAVE_ICONV) && defined (HAVE_WCHAR_H) && defined (HAVE_BTOWC)
+/* We use "btowc" as a sentinel to detect functioning wchar_t support.
+   We check for either __STDC_ISO_10646__ or a new-enough libiconv in
+   order to ensure we can convert to and from wchar_t.  We choose
+   libiconv version 0x10D because it was reported that earlier
+   versions do not always accept "wchar_t" as an encoding argument on
+   Solaris.  */
+#if defined (HAVE_ICONV) && defined (HAVE_WCHAR_H) && defined (HAVE_BTOWC) \
+  && (defined (__STDC_ISO_10646__) \
+      || defined (_LIBICONV_VERSION) && _LIBICONV_VERSION >= 0x10D)
 
 #include <wchar.h>
 #include <wctype.h>
@@ -63,6 +71,25 @@ typedef wint_t gdb_wint_t;
 
 #define LCST(X) L ## X
 
+/* If __STDC_ISO_10646__ is defined, then the host wchar_t is UCS-4.
+   We exploit this fact in the hope that there are hosts that define
+   this but which do not support "wchar_t" as an encoding argument to
+   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
+#elif defined (_LIBICONV_VERSION) && _LIBICONV_VERSION >= 0x10D
+#define INTERMEDIATE_ENCODING "wchar_t"
+#else
+/* This shouldn't happen, because the earlier #if should have filtered
+   out this case.  */
+#error "Neither __STDC_ISO_10646__ nor _LIBICONV_VERSION defined"
+#endif
+
 #else
 
 typedef char gdb_wchar_t;
@@ -80,8 +107,9 @@ typedef int gdb_wint_t;
    narrow encoding as our intermediate encoding.  However, if we are
    also providing a phony iconv, we might as well just stick with
    "wchar_t".  */
-#ifndef PHONY_ICONV
-#undef INTERMEDIATE_ENCODING
+#ifdef PHONY_ICONV
+#define INTERMEDIATE_ENCODING "wchar_t"
+#else
 #define INTERMEDIATE_ENCODING host_charset ()
 #endif