* [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
@ 2023-02-14 11:00 Felix Willgerodt
2023-02-14 15:14 ` Tom Tromey
0 siblings, 1 reply; 7+ messages in thread
From: Felix Willgerodt @ 2023-02-14 11:00 UTC (permalink / raw)
To: gdb-patches; +Cc: Felix Willgerodt
I fixed this a while ago for ifx, one of the two Intel compilers, in
8d624a9d8050ca96e154215c7858ac5c2d8b0b19.
Apparently I missed that the older ifort Intel compiler actually emits
slightly different debug info again:
0x0000007a: DW_TAG_base_type
DW_AT_byte_size (0x20)
DW_AT_encoding (DW_ATE_complex_float)
DW_AT_name ("COMPLEX(16)")
0x00000081: DW_TAG_base_type
DW_AT_byte_size (0x10)
DW_AT_encoding (DW_ATE_float)
DW_AT_name ("REAL(16)")
This fixes two failures in gdb.fortran/complex.exp with ifort.
---
gdb/i386-tdep.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index da4950ac259..acf22dba98d 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -8238,12 +8238,14 @@ i386_floatformat_for_type (struct gdbarch *gdbarch,
|| strcmp (name, "_Float128") == 0
|| strcmp (name, "complex _Float128") == 0
|| strcmp (name, "complex(kind=16)") == 0
+ || strcmp (name, "COMPLEX(16)") == 0
|| strcmp (name, "complex*32") == 0
|| strcmp (name, "COMPLEX*32") == 0
|| strcmp (name, "quad complex") == 0
|| strcmp (name, "real(kind=16)") == 0
|| strcmp (name, "real*16") == 0
- || strcmp (name, "REAL*16") == 0)
+ || strcmp (name, "REAL*16") == 0
+ || strcmp (name, "REAL(16)") == 0)
return floatformats_ieee_quad;
return default_floatformat_for_type (gdbarch, name, len);
--
2.39.1
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
2023-02-14 11:00 [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler Felix Willgerodt
@ 2023-02-14 15:14 ` Tom Tromey
2023-02-15 9:05 ` Willgerodt, Felix
0 siblings, 1 reply; 7+ messages in thread
From: Tom Tromey @ 2023-02-14 15:14 UTC (permalink / raw)
To: Felix Willgerodt via Gdb-patches; +Cc: Felix Willgerodt
>>>>> "Felix" == Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org> writes:
Felix> I fixed this a while ago for ifx, one of the two Intel compilers, in
Felix> 8d624a9d8050ca96e154215c7858ac5c2d8b0b19.
Felix> Apparently I missed that the older ifort Intel compiler actually emits
Felix> slightly different debug info again:
Thank you, this is ok.
Approved-By: Tom Tromey <tom@tromey.com>
Felix> @@ -8238,12 +8238,14 @@ i386_floatformat_for_type (struct gdbarch *gdbarch,
Felix> || strcmp (name, "_Float128") == 0
Felix> || strcmp (name, "complex _Float128") == 0
Felix> || strcmp (name, "complex(kind=16)") == 0
Felix> + || strcmp (name, "COMPLEX(16)") == 0
Felix> || strcmp (name, "complex*32") == 0
Felix> || strcmp (name, "COMPLEX*32") == 0
Felix> || strcmp (name, "quad complex") == 0
Felix> || strcmp (name, "real(kind=16)") == 0
Felix> || strcmp (name, "real*16") == 0
Felix> - || strcmp (name, "REAL*16") == 0)
Felix> + || strcmp (name, "REAL*16") == 0
Felix> + || strcmp (name, "REAL(16)") == 0)
Felix> return floatformats_ieee_quad;
Not your fault but this whole approach seems bad.
Tom
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
2023-02-14 15:14 ` Tom Tromey
@ 2023-02-15 9:05 ` Willgerodt, Felix
2023-02-15 16:52 ` Tom Tromey
0 siblings, 1 reply; 7+ messages in thread
From: Willgerodt, Felix @ 2023-02-15 9:05 UTC (permalink / raw)
To: Tom Tromey, Felix Willgerodt via Gdb-patches
> -----Original Message-----
> From: Tom Tromey <tom@tromey.com>
> Sent: Dienstag, 14. Februar 2023 16:14
> To: Felix Willgerodt via Gdb-patches <gdb-patches@sourceware.org>
> Cc: Willgerodt, Felix <felix.willgerodt@intel.com>
> Subject: Re: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort
> compiler.
>
> >>>>> "Felix" == Felix Willgerodt via Gdb-patches <gdb-
> patches@sourceware.org> writes:
>
> Felix> I fixed this a while ago for ifx, one of the two Intel compilers, in
> Felix> 8d624a9d8050ca96e154215c7858ac5c2d8b0b19.
>
> Felix> Apparently I missed that the older ifort Intel compiler actually emits
> Felix> slightly different debug info again:
>
> Thank you, this is ok.
>
> Approved-By: Tom Tromey <tom@tromey.com>
Thanks, I pushed this now.
> Felix> @@ -8238,12 +8238,14 @@ i386_floatformat_for_type (struct gdbarch
> *gdbarch,
> Felix> || strcmp (name, "_Float128") == 0
> Felix> || strcmp (name, "complex _Float128") == 0
> Felix> || strcmp (name, "complex(kind=16)") == 0
> Felix> + || strcmp (name, "COMPLEX(16)") == 0
> Felix> || strcmp (name, "complex*32") == 0
> Felix> || strcmp (name, "COMPLEX*32") == 0
> Felix> || strcmp (name, "quad complex") == 0
> Felix> || strcmp (name, "real(kind=16)") == 0
> Felix> || strcmp (name, "real*16") == 0
> Felix> - || strcmp (name, "REAL*16") == 0)
> Felix> + || strcmp (name, "REAL*16") == 0
> Felix> + || strcmp (name, "REAL(16)") == 0)
> Felix> return floatformats_ieee_quad;
>
> Not your fault but this whole approach seems bad.
Agreed. But can we change anything really?
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
2023-02-15 9:05 ` Willgerodt, Felix
@ 2023-02-15 16:52 ` Tom Tromey
2023-02-20 9:17 ` Willgerodt, Felix
0 siblings, 1 reply; 7+ messages in thread
From: Tom Tromey @ 2023-02-15 16:52 UTC (permalink / raw)
To: Willgerodt, Felix via Gdb-patches; +Cc: Tom Tromey, Willgerodt, Felix
>>>>> "Felix" == Willgerodt, Felix via Gdb-patches <gdb-patches@sourceware.org> writes:
Felix> || strcmp (name, "_Float128") == 0
Felix> || strcmp (name, "complex _Float128") == 0
Felix> || strcmp (name, "complex(kind=16)") == 0
Felix> + || strcmp (name, "COMPLEX(16)") == 0
Felix> || strcmp (name, "complex*32") == 0
Felix> || strcmp (name, "COMPLEX*32") == 0
Felix> || strcmp (name, "quad complex") == 0
Felix> || strcmp (name, "real(kind=16)") == 0
Felix> || strcmp (name, "real*16") == 0
Felix> - || strcmp (name, "REAL*16") == 0)
Felix> + || strcmp (name, "REAL*16") == 0
Felix> + || strcmp (name, "REAL(16)") == 0)
Felix> return floatformats_ieee_quad;
>> Not your fault but this whole approach seems bad.
Felix> Agreed. But can we change anything really?
I suppose ideally what we would need is extra information in the DWARF.
Although... i386_floatformat_for_type is explicitly checking for
len==128. Is there some other float format matching this on i386?
Perhaps checking the name is unnecessary.
Also perhaps this could be fixed by adding some new gdbarch hook so that
default_floatformat_for_type could handle this case.
thanks,
Tom
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
2023-02-15 16:52 ` Tom Tromey
@ 2023-02-20 9:17 ` Willgerodt, Felix
2023-02-24 14:11 ` Tom Tromey
0 siblings, 1 reply; 7+ messages in thread
From: Willgerodt, Felix @ 2023-02-20 9:17 UTC (permalink / raw)
To: Tom Tromey, Willgerodt, Felix via Gdb-patches
> >>>>> "Felix" == Willgerodt, Felix via Gdb-patches <gdb-
> patches@sourceware.org> writes:
>
> Felix> || strcmp (name, "_Float128") == 0
> Felix> || strcmp (name, "complex _Float128") == 0
> Felix> || strcmp (name, "complex(kind=16)") == 0
> Felix> + || strcmp (name, "COMPLEX(16)") == 0
> Felix> || strcmp (name, "complex*32") == 0
> Felix> || strcmp (name, "COMPLEX*32") == 0
> Felix> || strcmp (name, "quad complex") == 0
> Felix> || strcmp (name, "real(kind=16)") == 0
> Felix> || strcmp (name, "real*16") == 0
> Felix> - || strcmp (name, "REAL*16") == 0)
> Felix> + || strcmp (name, "REAL*16") == 0
> Felix> + || strcmp (name, "REAL(16)") == 0)
> Felix> return floatformats_ieee_quad;
>
> >> Not your fault but this whole approach seems bad.
>
> Felix> Agreed. But can we change anything really?
>
> I suppose ideally what we would need is extra information in the DWARF.
>
> Although... i386_floatformat_for_type is explicitly checking for
> len==128. Is there some other float format matching this on i386?
As far as I know, the actual x87 FPU supports only an extended-double
format with 80 bits and the SSE/AVX units only support double-precision.
default_floatformat_for_type() has an explicit comment about it as well.
When examining memory for this Fortran test, I see 128-bit values in
binary128 format, so I assume that this is just a software/compiler feature.
There is also decimal128 support in e.g. gcc. I tried it only briefly,
we don't end up in i386_floatformat_for_type for those types, but
GDB prints them just fine. I assume as they are marked as
DW_ATE_decimal_float instead of DW_ATE_float, but I didn't look into
it in detail.
I am not aware of any other float types that exist with this length.
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
2023-02-20 9:17 ` Willgerodt, Felix
@ 2023-02-24 14:11 ` Tom Tromey
2023-02-28 10:21 ` Willgerodt, Felix
0 siblings, 1 reply; 7+ messages in thread
From: Tom Tromey @ 2023-02-24 14:11 UTC (permalink / raw)
To: Willgerodt, Felix via Gdb-patches; +Cc: Tom Tromey, Willgerodt, Felix
> When examining memory for this Fortran test, I see 128-bit values in
> binary128 format, so I assume that this is just a software/compiler feature.
> There is also decimal128 support in e.g. gcc. I tried it only briefly,
> we don't end up in i386_floatformat_for_type for those types, but
> GDB prints them just fine. I assume as they are marked as
> DW_ATE_decimal_float instead of DW_ATE_float, but I didn't look into
> it in detail.
> I am not aware of any other float types that exist with this length.
I wonder, then, if this patch would work?
This way we would not have to curate a list of names.
Tom
diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 476d17f1efd..57e50ffdd73 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -8277,20 +8277,8 @@ static const struct floatformat **
i386_floatformat_for_type (struct gdbarch *gdbarch,
const char *name, int len)
{
- if (len == 128 && name)
- if (strcmp (name, "__float128") == 0
- || strcmp (name, "_Float128") == 0
- || strcmp (name, "complex _Float128") == 0
- || strcmp (name, "complex(kind=16)") == 0
- || strcmp (name, "COMPLEX(16)") == 0
- || strcmp (name, "complex*32") == 0
- || strcmp (name, "COMPLEX*32") == 0
- || strcmp (name, "quad complex") == 0
- || strcmp (name, "real(kind=16)") == 0
- || strcmp (name, "real*16") == 0
- || strcmp (name, "REAL*16") == 0
- || strcmp (name, "REAL(16)") == 0)
- return floatformats_ieee_quad;
+ if (len == 128)
+ return floatformats_ieee_quad;
return default_floatformat_for_type (gdbarch, name, len);
}
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.
2023-02-24 14:11 ` Tom Tromey
@ 2023-02-28 10:21 ` Willgerodt, Felix
0 siblings, 0 replies; 7+ messages in thread
From: Willgerodt, Felix @ 2023-02-28 10:21 UTC (permalink / raw)
To: Tom Tromey, Willgerodt, Felix via Gdb-patches
> -----Original Message-----
> From: Tom Tromey <tom@tromey.com>
> Sent: Freitag, 24. Februar 2023 15:11
> To: Willgerodt, Felix via Gdb-patches <gdb-patches@sourceware.org>
> Cc: Tom Tromey <tom@tromey.com>; Willgerodt, Felix
> <felix.willgerodt@intel.com>
> Subject: Re: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort
> compiler.
>
> > When examining memory for this Fortran test, I see 128-bit values in
> > binary128 format, so I assume that this is just a software/compiler feature.
> > There is also decimal128 support in e.g. gcc. I tried it only briefly,
> > we don't end up in i386_floatformat_for_type for those types, but
> > GDB prints them just fine. I assume as they are marked as
> > DW_ATE_decimal_float instead of DW_ATE_float, but I didn't look into
> > it in detail.
>
> > I am not aware of any other float types that exist with this length.
>
> I wonder, then, if this patch would work?
> This way we would not have to curate a list of names.
>
> Tom
>
> diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
> index 476d17f1efd..57e50ffdd73 100644
> --- a/gdb/i386-tdep.c
> +++ b/gdb/i386-tdep.c
> @@ -8277,20 +8277,8 @@ static const struct floatformat **
> i386_floatformat_for_type (struct gdbarch *gdbarch,
> const char *name, int len)
> {
> - if (len == 128 && name)
> - if (strcmp (name, "__float128") == 0
> - || strcmp (name, "_Float128") == 0
> - || strcmp (name, "complex _Float128") == 0
> - || strcmp (name, "complex(kind=16)") == 0
> - || strcmp (name, "COMPLEX(16)") == 0
> - || strcmp (name, "complex*32") == 0
> - || strcmp (name, "COMPLEX*32") == 0
> - || strcmp (name, "quad complex") == 0
> - || strcmp (name, "real(kind=16)") == 0
> - || strcmp (name, "real*16") == 0
> - || strcmp (name, "REAL*16") == 0
> - || strcmp (name, "REAL(16)") == 0)
> - return floatformats_ieee_quad;
> + if (len == 128)
> + return floatformats_ieee_quad;
>
> return default_floatformat_for_type (gdbarch, name, len);
> }
I tested this quickly and see some regressions in gdb.base/complex-.parts.exp,
gdb.base/bfp-test.exp and gdb.base/structs.exp (and a handful of others) on x86,
with multiple compilers. Also gcc on Fedora 37 and Ubuntu 22.04.
I didn't have the time to dig too deep. It seems like we return ieee_quad for
some cases where we shouldn’t.
(gdb) bt 5
#0 i386_floatformat_for_type (gdbarch=0x55555848f520, name=0x555558b5c760 "long double",
len=128) at sources/gdb/gdb/i386-tdep.c:8281
#1 0x0000555555cd9e7e in gdbarch_floatformat_for_type (gdbarch=0x55555848f520,
name=0x555558b5c760 "long double", length=128)
at sources/gdb/gdb/gdbarch.c:1679
#2 0x0000555555f6fc9f in dwarf2_init_float_type (objfile=0x7fffe8021d00, bits=128,
name=0x555558b5c760 "long double", name_hint=0x555558b5c760 "long double",
byte_order=BFD_ENDIAN_LITTLE) at sources/gdb/gdb/dwarf2/read.c:15031
#3 0x0000555555f70543 in read_base_type (die=0x555558908f10, cu=0x7fffd8006970)
at sources/gdb/gdb/dwarf2/read.c:15270
#4 0x0000555555f7b2be in read_type_die_1 (die=0x555558908f10, cu=0x7fffd8006970)
at sources/gdb/gdb/dwarf2/read.c:19631
This seems to pass 128 bits for long double, where your patch did expect 80 bits.
The 80 bit length for x86 is only handled in arch-utils.c:default_floatformat_for_type.
I wonder if that could be streamlined a bit, not having to call gdbarch functions twice
to figure out the format.
I don't know why GDB passes 128 bit from the dwarf reader. I was debugging
complex-parts only. In dwarf, we see the type having 256 bits. So maybe GDB splits
it to 128 bit, as it is a complex?
Felix
Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2023-02-28 10:21 UTC | newest]
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2023-02-14 11:00 [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler Felix Willgerodt
2023-02-14 15:14 ` Tom Tromey
2023-02-15 9:05 ` Willgerodt, Felix
2023-02-15 16:52 ` Tom Tromey
2023-02-20 9:17 ` Willgerodt, Felix
2023-02-24 14:11 ` Tom Tromey
2023-02-28 10:21 ` Willgerodt, Felix
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