Re: Memory corruption for host double format different from target double format

Thomas Schwinge
2012-08-29T15:37:29Z

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Hi!

On Fri, 10 Aug 2012 16:31:47 +0200, Mark Kettenis <mark.kettenis@xs4all.nl> wrote:
> > Date: Fri, 10 Aug 2012 14:56:46 +0200 (CEST)
> > From: "Ulrich Weigand" <uweigand@de.ibm.com>
> >
> > Yao Qi wrote:
> > > On Friday, August 10, 2012 11:32:53 AM Thomas Schwinge wrote:
> > > > That is, if set_gdbarch_double_format has not been called, it will
> > > > default to floatformats_ieee_double -- even though set_gdbarch_double_bit
> > > > may have been called setting it unequal to the 64-bit double format.
> > > > Hmm, and gdbarch.c:verify_gdbarch has the following comment on top of it:
> > > > Ensure that all values in a GDBARCH are reasonable. ;-)
> > >
> > > Looks like some checking like this is missing?
> > >
> > > gdbarch->float_format->totalsize <= gdbarch->float_bit
> > > gdbarch->double_format->totalsize <= gdbarch->double_bit
> >
> > In fact, I'd prefer to make gdbarch_double_format etc. *mandatory*
> > and gdbarch_double_bit etc. optional, defaulting to the format size.
> > (Currently, _bit is mandatory and _format is optional.)
> >
> > This would mean that nearly all calls to set_gdbarch_double_bit
> > could go away, with the exception of special cases like "long double"
> > on i386 ...
>
> Initializing _bit based on _format by default makes sense, but I don't
> think this is easy to implement given the way how the gdbarch.c code
> is generated.
>
> Making _format mandatory doesn't make sense to me though. I'd say
> that ieee_single and ieee_double are perfectly reasonable defaults for
> float_format and double_format.

Is there a reasonable way for at least detecting the mismatch that I
happened to observe for SH?

Other than that, OK to check in the following? I have only tested the SH
bits; no maintainer listed for h8300, Stephane CCed for m68hc11.

gdb/
* h8300-tdep.c (h8300_gdbarch_init): Invoke
set_gdbarch_double_format and set_gdbarch_long_double_format.
* m68hc11-tdep.c (m68hc11_gdbarch_init): Invoke
set_gdbarch_double_format.
* sh-tdep.c (sh_gdbarch_init): Likewise.

diff --git a/gdb/h8300-tdep.c b/gdb/h8300-tdep.c
index 7fc4daa..bcb769e 100644
--- a/gdb/h8300-tdep.c
+++ b/gdb/h8300-tdep.c
@@ -1351,7 +1351,9 @@ h8300_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_gdbarch_long_bit (gdbarch, 4 * TARGET_CHAR_BIT);
set_gdbarch_long_long_bit (gdbarch, 8 * TARGET_CHAR_BIT);
set_gdbarch_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
+ set_gdbarch_double_format (gdbarch, floatformats_ieee_single);
set_gdbarch_long_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
+ set_gdbarch_long_double_format (gdbarch, floatformats_ieee_single);

set_gdbarch_believe_pcc_promotion (gdbarch, 1);

diff --git a/gdb/m68hc11-tdep.c b/gdb/m68hc11-tdep.c
index 79629ef..cd32459 100644
--- a/gdb/m68hc11-tdep.c
+++ b/gdb/m68hc11-tdep.c
@@ -1498,7 +1498,16 @@ m68hc11_gdbarch_init (struct gdbarch_info info,
set_gdbarch_short_bit (gdbarch, 16);
set_gdbarch_int_bit (gdbarch, elf_flags & E_M68HC11_I32 ? 32 : 16);
set_gdbarch_float_bit (gdbarch, 32);
- set_gdbarch_double_bit (gdbarch, elf_flags & E_M68HC11_F64 ? 64 : 32);
+ if (elf_flags & E_M68HC11_F64)
+ {
+ set_gdbarch_double_bit (gdbarch, 64);
+ set_gdbarch_double_format (gdbarch, floatformats_ieee_double);
+ }
+ else
+ {
+ set_gdbarch_double_bit (gdbarch, 32);
+ set_gdbarch_double_format (gdbarch, floatformats_ieee_single);
+ }
set_gdbarch_long_double_bit (gdbarch, 64);
set_gdbarch_long_bit (gdbarch, 32);
set_gdbarch_ptr_bit (gdbarch, 16);
diff --git a/gdb/sh-tdep.c b/gdb/sh-tdep.c
index 1ede13a..caf940d 100644
--- a/gdb/sh-tdep.c
+++ b/gdb/sh-tdep.c
@@ -2299,6 +2299,7 @@ sh_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
case bfd_mach_sh2e:
/* doubles on sh2e and sh3e are actually 4 byte. */
set_gdbarch_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
+ set_gdbarch_double_format (gdbarch, floatformats_ieee_single);

set_gdbarch_register_name (gdbarch, sh_sh2e_register_name);
set_gdbarch_register_type (gdbarch, sh_sh3e_register_type);
@@ -2344,6 +2345,7 @@ sh_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
case bfd_mach_sh2a_or_sh3e:
/* doubles on sh2e and sh3e are actually 4 byte. */
set_gdbarch_double_bit (gdbarch, 4 * TARGET_CHAR_BIT);
+ set_gdbarch_double_format (gdbarch, floatformats_ieee_single);

set_gdbarch_register_name (gdbarch, sh_sh3e_register_name);
set_gdbarch_register_type (gdbarch, sh_sh3e_register_type);