[1/2] RISC-V: Print FP regs as union of float types.
Commit Message
A 64-bit FP register can hold either a single or double float value, so
print it as both types by using a union type for FP registers. Likewise
for 128-bit regs which can also hold long double.
gdb/
* riscv-tdep.c (riscv_fpreg_d_type, riscv_fpreg_q_type): New.
(riscv_register_type): Use them.
(riscv_print_one_register_info): Handle union of floats same as float.
* riscv-tdep.h (struct gdbarch_tdep): Add riscv_fpreg_d_type and
riscv_fpreg_q_type fields.
---
gdb/riscv-tdep.c | 85 ++++++++++++++++++++++++++++++++++++++++++++++--
gdb/riscv-tdep.h | 4 +++
2 files changed, 86 insertions(+), 3 deletions(-)
Comments
On Fri, 19 Oct 2018 14:49:07 -0700
Jim Wilson <jimw@sifive.com> wrote:
> A 64-bit FP register can hold either a single or double float value, so
> print it as both types by using a union type for FP registers. Likewise
> for 128-bit regs which can also hold long double.
>
> gdb/
> * riscv-tdep.c (riscv_fpreg_d_type, riscv_fpreg_q_type): New.
> (riscv_register_type): Use them.
> (riscv_print_one_register_info): Handle union of floats same as float.
> * riscv-tdep.h (struct gdbarch_tdep): Add riscv_fpreg_d_type and
> riscv_fpreg_q_type fields.
This is okay, except for the following nits...
> +static struct type *
> +riscv_fpreg_d_type (struct gdbarch *gdbarch)
> +{
> + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> + if (!tdep->riscv_fpreg_d_type)
The GDB coding standard say that this must be coded as:
if (tdep->riscv_fpreg_d_type == NULL)
Though I think we prefer nullptr over NULL these days.
(I realize that there's code in GDB which does not conform to this
standard.)
Likewise, here:
> +static struct type *
> +riscv_fpreg_q_type (struct gdbarch *gdbarch)
> +{
> + struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
> +
> + if (!tdep->riscv_fpreg_q_type)
Kevin
On Sat, Oct 20, 2018 at 2:38 PM Kevin Buettner <kevinb@redhat.com> wrote:
>
> On Fri, 19 Oct 2018 14:49:07 -0700
> Jim Wilson <jimw@sifive.com> wrote:
>
> > A 64-bit FP register can hold either a single or double float value, so
> > print it as both types by using a union type for FP registers. Likewise
> > for 128-bit regs which can also hold long double.
> >
> > gdb/
> > * riscv-tdep.c (riscv_fpreg_d_type, riscv_fpreg_q_type): New.
> > (riscv_register_type): Use them.
> > (riscv_print_one_register_info): Handle union of floats same as float.
> > * riscv-tdep.h (struct gdbarch_tdep): Add riscv_fpreg_d_type and
> > riscv_fpreg_q_type fields.
>
> The GDB coding standard say that this must be coded as:
>
> if (tdep->riscv_fpreg_d_type == NULL)
>
> Though I think we prefer nullptr over NULL these days.
I updated the patch to use nullptr, retested it, and committed it.
Jim
@@ -495,6 +495,76 @@ riscv_register_name (struct gdbarch *gdbarch, int regnum)
return NULL;
}
+/* Construct a type for 64-bit FP registers. */
+
+static struct type *
+riscv_fpreg_d_type (struct gdbarch *gdbarch)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ if (!tdep->riscv_fpreg_d_type)
+ {
+ const struct builtin_type *bt = builtin_type (gdbarch);
+
+ /* The type we're building is this: */
+#if 0
+ union __gdb_builtin_type_fpreg_d
+ {
+ float f;
+ double d;
+ };
+#endif
+
+ struct type *t;
+
+ t = arch_composite_type (gdbarch,
+ "__gdb_builtin_type_fpreg_d", TYPE_CODE_UNION);
+ append_composite_type_field (t, "float", bt->builtin_float);
+ append_composite_type_field (t, "double", bt->builtin_double);
+ TYPE_VECTOR (t) = 1;
+ TYPE_NAME (t) = "builtin_type_fpreg_d";
+ tdep->riscv_fpreg_d_type = t;
+ }
+
+ return tdep->riscv_fpreg_d_type;
+}
+
+/* Construct a type for 128-bit FP registers. */
+
+static struct type *
+riscv_fpreg_q_type (struct gdbarch *gdbarch)
+{
+ struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+ if (!tdep->riscv_fpreg_q_type)
+ {
+ const struct builtin_type *bt = builtin_type (gdbarch);
+
+ /* The type we're building is this: */
+#if 0
+ union __gdb_builtin_type_fpreg_d
+ {
+ float f;
+ double d;
+ long double ld;
+ };
+#endif
+
+ struct type *t;
+
+ t = arch_composite_type (gdbarch,
+ "__gdb_builtin_type_fpreg_q", TYPE_CODE_UNION);
+ append_composite_type_field (t, "float", bt->builtin_float);
+ append_composite_type_field (t, "double", bt->builtin_double);
+ append_composite_type_field (t, "long double", bt->builtin_long_double);
+ TYPE_VECTOR (t) = 1;
+ TYPE_NAME (t) = "builtin_type_fpreg_q";
+ tdep->riscv_fpreg_q_type = t;
+ }
+
+ return tdep->riscv_fpreg_q_type;
+}
+
/* Implement the register_type gdbarch method. */
static struct type *
@@ -537,9 +607,9 @@ riscv_register_type (struct gdbarch *gdbarch, int regnum)
case 4:
return builtin_type (gdbarch)->builtin_float;
case 8:
- return builtin_type (gdbarch)->builtin_double;
+ return riscv_fpreg_d_type (gdbarch);
case 16:
- return builtin_type (gdbarch)->builtin_long_double;
+ return riscv_fpreg_q_type (gdbarch);
default:
internal_error (__FILE__, __LINE__,
_("unknown isa regsize %i"), regsize);
@@ -591,7 +661,16 @@ riscv_print_one_register_info (struct gdbarch *gdbarch,
print_raw_format = (value_entirely_available (val)
&& !value_optimized_out (val));
- if (TYPE_CODE (regtype) == TYPE_CODE_FLT)
+ if (TYPE_CODE (regtype) == TYPE_CODE_FLT
+ || (TYPE_CODE (regtype) == TYPE_CODE_UNION
+ && TYPE_NFIELDS (regtype) == 2
+ && TYPE_CODE (TYPE_FIELD_TYPE (regtype, 0)) == TYPE_CODE_FLT
+ && TYPE_CODE (TYPE_FIELD_TYPE (regtype, 1)) == TYPE_CODE_FLT)
+ || (TYPE_CODE (regtype) == TYPE_CODE_UNION
+ && TYPE_NFIELDS (regtype) == 3
+ && TYPE_CODE (TYPE_FIELD_TYPE (regtype, 0)) == TYPE_CODE_FLT
+ && TYPE_CODE (TYPE_FIELD_TYPE (regtype, 1)) == TYPE_CODE_FLT
+ && TYPE_CODE (TYPE_FIELD_TYPE (regtype, 2)) == TYPE_CODE_FLT))
{
struct value_print_options opts;
const gdb_byte *valaddr = value_contents_for_printing (val);
@@ -78,6 +78,10 @@ struct gdbarch_tdep
features that are supported on the target. These could be cached from
the target, or read from the executable when available. */
unsigned core_features;
+
+ /* ISA-specific data types. */
+ struct type *riscv_fpreg_d_type;
+ struct type *riscv_fpreg_q_type;
};
/* Return the width in bytes of the general purpose registers for GDBARCH. */