[RFA/commit] Fix printing of wide characters (Ada and C)

[RFA/commit] Fix printing of wide characters (Ada and C)

[Joel Brobecker]

Wide_Characters and Wide_Wide_Characters are incorrectly printed.
Same for the C wchar_t type.  Consider for instance:

    Medium : Wide_Character := Wide_Character'Val(16#dead#);

Trying to print the value of this variable yields:

    (gdb) p medium
    $1 = 57005 '["ad"]'

The integer value is correct (57005 = 0xdead), but the character
representation is not, it should be:

    $1 = 57005 '["dead"]'

Same for Wide_Wide_Characters.  For the C wchar_t type, we get the
same sort of issue, but with the C syntax...

    wchar_t single = 0xbeef;

    (gdb) p single
    $1 = 48879 L'\357'

There were two issues:
   (a) The first issue was in ada-valprint, where we were assuming
       that character types were 1 byte long;
   (b) The second problem was in c-valprint, where we were down-casting
       the integer value of the character to type `unsigned char',
       causing use to lose all but the lowest byte.

gdb/ChangeLog:

        * ada-valprint. (ada_printchar): Use the correct type length
        in call to ada_emit_char.
        * c-valprint.c (c_val_print): Remove cast in call to LA_PRINT_CHAR.

Tested on x86_64-linux.  Ok to commit?

Thanks,
-- 
Joel

---
 gdb/ada-valprint.c |    2 +-
 gdb/c-valprint.c   |    6 ++----
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/gdb/ada-valprint.c b/gdb/ada-valprint.c
index 630ceb5..ee37617 100644
--- a/gdb/ada-valprint.c
+++ b/gdb/ada-valprint.c
@@ -368,7 +368,7 @@ void
 ada_printchar (int c, struct type *type, struct ui_file *stream)
 {
   fputs_filtered ("'", stream);
-  ada_emit_char (c, type, stream, '\'', 1);
+  ada_emit_char (c, type, stream, '\'', TYPE_LENGTH (type));
   fputs_filtered ("'", stream);
 }
 
diff --git a/gdb/c-valprint.c b/gdb/c-valprint.c
index 0c23c7e..c6d3eae 100644
--- a/gdb/c-valprint.c
+++ b/gdb/c-valprint.c
@@ -536,9 +536,7 @@ c_val_print (struct type *type, const gdb_byte *valaddr,
 	  if (c_textual_element_type (unresolved_type, options->format))
 	    {
 	      fputs_filtered (" ", stream);
-	      LA_PRINT_CHAR ((unsigned char) unpack_long (type,
-							  valaddr
-							  + embedded_offset),
+	      LA_PRINT_CHAR (unpack_long (type, valaddr + embedded_offset),
 			     unresolved_type, stream);
 	    }
 	}
@@ -561,7 +559,7 @@ c_val_print (struct type *type, const gdb_byte *valaddr,
 	  else
 	    fprintf_filtered (stream, "%d", (int) val);
 	  fputs_filtered (" ", stream);
-	  LA_PRINT_CHAR ((unsigned char) val, unresolved_type, stream);
+	  LA_PRINT_CHAR (val, unresolved_type, stream);
 	}
       break;
 
-- 
1.7.1

Re: [RFA/commit] Fix printing of wide characters (Ada and C)

[Tom Tromey]

>>>>> "Joel" == Joel Brobecker <brobecker@adacore.com> writes:

Joel>    (b) The second problem was in c-valprint, where we were down-casting
Joel>        the integer value of the character to type `unsigned char',
Joel>        causing use to lose all but the lowest byte.

Ouch.  I am really surprised we missed this for so long.

Joel>         * ada-valprint. (ada_printchar): Use the correct type length
Joel>         in call to ada_emit_char.
Joel>         * c-valprint.c (c_val_print): Remove cast in call to LA_PRINT_CHAR.

Joel> Tested on x86_64-linux.  Ok to commit?

It looks good to me.  I think it should go on the 7.2 branch as well.

Tom

Re: [RFA/commit] Fix printing of wide characters (Ada and C)

[Joel Brobecker]

> Joel>         * ada-valprint. (ada_printchar): Use the correct type length
> Joel>         in call to ada_emit_char.
> Joel>         * c-valprint.c (c_val_print): Remove cast in call to LA_PRINT_CHAR.
> 
> It looks good to me.  I think it should go on the 7.2 branch as well.

Thanks! Patch checked in HEAD, and I'm retesting on 7.2 before
checking in...  I expect to commit them on the branch in a bit,
if all goes well.

-- 
Joel