[gdb] Improve printing of float formats

Currently, on x86_64, a little endian target, I get:
...
$ gdb -q -batch -ex "maint print architecture" | grep " = floatformat"
gdbarch_dump: bfloat16_format = floatformat_bfloat16_big
gdbarch_dump: double_format = floatformat_ieee_double_big
gdbarch_dump: float_format = floatformat_ieee_single_big
gdbarch_dump: half_format = floatformat_ieee_half_big
gdbarch_dump: long_double_format = floatformat_i387_ext
...
which suggests big endian.

This is due to this bit of code in pformat:
...
    /* Just print out one of them - this is only for diagnostics.  */
    return format[0]->name;
...

Fix this by using gdbarch_byte_order to pick the appropriate index, such that
we have the more accurate:
...
gdbarch_dump: bfloat16_format = floatformat_bfloat16_little
gdbarch_dump: half_format = floatformat_ieee_half_little
gdbarch_dump: float_format = floatformat_ieee_single_little
gdbarch_dump: double_format = floatformat_ieee_double_little
gdbarch_dump: long_double_format = floatformat_i387_ext
...

Tested on x86_64-linux.

1 files changed, 4 insertions, 4 deletions

diff --git a/gdb/arch-utils.c b/gdb/arch-utils.c
index 7b84daf..60ffdc5 100644
--- a/gdb/arch-utils.c
+++ b/gdb/arch-utils.c
@@ -1104,13 +1104,13 @@ show_gdbarch_debug (struct ui_file *file, int from_tty,
 }
 
 static const char *
-pformat (const struct floatformat **format)
+pformat (struct gdbarch *gdbarch, const struct floatformat **format)
 {
   if (format == NULL)
     return "(null)";
-  else
-    /* Just print out one of them - this is only for diagnostics.  */
-    return format[0]->name;
+
+  int format_index = gdbarch_byte_order (gdbarch) == BFD_ENDIAN_LITTLE ? 1 : 0;
+  return format[format_index]->name;
 }
 
 static const char *