Re: [PATCHv2] gdb/fortran: Use floatformats_ia64_quad for fortran 16-byte floats

[Andrew Burgess <andrew.burgess@embecosm.com>]

* Andrew Burgess <andrew.burgess@embecosm.com> [2019-05-16 17:00:58 +0100]:

> This new version moves the use of floatformats_ia64_quad out of
> f-lang.c, which I think is an improvement.  With this done I plan to
> push this patch shortly unless anyone complains.

This has now been pushed.

Thanks,
Andrew



> 
> Thanks,
> Andrew
> 
> 
> ---
> 
> PR gdb/18644 is caused by GDB using the wrong floating point format
> for gfortran's 16-byte floating point type, including when the 16-byte
> float is used as the component of a 32-byte complex type.
> 
> This commit addresses the issue in two places, first in i386-tdep.c,
> there is already some code to force the use of floatformats_ia64_quad
> for specific named types, this is extended to include the type names
> that gfortran uses for its 16-byte floats.
> 
> Second, the builtin 16-byte float type (in f-lang.c) is changed so it
> no longer uses gdbarch_long_double_format.  On i386 this type is not
> 16-bytes, but is smaller, this is not what gfortran is expecting.
> Instead we now use gdbarch_floatformat_for_type and ask for a
> 16-byte (128 bit) type using the common gfortran type name.  This is
> then spotted in i386-tdep.c (thanks to the first change above) and we
> again get floatformats_ia64_quad returned.
> 
> This patch was tested on X86-64/GNU-Linux using '--target_board=unix'
> and '--target_board=unix/-m32', and resolves all of the known failures
> associated with PR gdb/18644.  I've also added the test case from the
> original bug report.
> 
> gdb/ChangeLog:
> 
> 	PR gdb/18644:
> 	* f-lang.c (build_fortran_types): Use floatformats_ia64_quad for
> 	16-byte floats.
> 	* i386-tdep.c (i386_floatformat_for_type): Use
> 	floatformats_ia64_quad for the 16-byte floating point component
> 	within a fortran 32-byte complex number.
> 
> gdb/testsuite/ChangeLog:
> 
> 	PR gdb/18644
> 	* gdb.fortran/complex.exp: Remove setup_kfail calls.
> 	* gdb.fortran/printing-types.exp: Add new test.
> 	* gdb.fortran/printing-types.f90: Add 16-byte real variable for
> 	testing.
> 	* gdb.fortran/type-kinds.exp (test_cast_1_to_type_kind): Remove
> 	setup_kfail call.
> ---
>  gdb/ChangeLog                                |  9 +++++++++
>  gdb/f-lang.c                                 |  4 ++--
>  gdb/i386-tdep.c                              |  4 +++-
>  gdb/testsuite/ChangeLog                      | 10 ++++++++++
>  gdb/testsuite/gdb.fortran/complex.exp        |  2 --
>  gdb/testsuite/gdb.fortran/printing-types.exp |  1 +
>  gdb/testsuite/gdb.fortran/printing-types.f90 |  2 ++
>  gdb/testsuite/gdb.fortran/type-kinds.exp     |  6 ------
>  8 files changed, 27 insertions(+), 11 deletions(-)
> 
> diff --git a/gdb/f-lang.c b/gdb/f-lang.c
> index 9da6fdb3e1c..5855c68b38c 100644
> --- a/gdb/f-lang.c
> +++ b/gdb/f-lang.c
> @@ -727,9 +727,9 @@ build_fortran_types (struct gdbarch *gdbarch)
>    builtin_f_type->builtin_real_s8
>      = arch_float_type (gdbarch, gdbarch_double_bit (gdbarch),
>  		       "real*8", gdbarch_double_format (gdbarch));
> +  auto fmt = gdbarch_floatformat_for_type (gdbarch, "real(kind=16)", 128);
>    builtin_f_type->builtin_real_s16
> -    = arch_float_type (gdbarch, gdbarch_long_double_bit (gdbarch),
> -		       "real*16", gdbarch_long_double_format (gdbarch));
> +    = arch_float_type (gdbarch, 128, "real*16", fmt);
>  
>    builtin_f_type->builtin_complex_s8
>      = arch_complex_type (gdbarch, "complex*8",
> diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
> index 54d9dd873b8..66fc6d679e2 100644
> --- a/gdb/i386-tdep.c
> +++ b/gdb/i386-tdep.c
> @@ -8158,7 +8158,9 @@ i386_floatformat_for_type (struct gdbarch *gdbarch,
>    if (len == 128 && name)
>      if (strcmp (name, "__float128") == 0
>  	|| strcmp (name, "_Float128") == 0
> -	|| strcmp (name, "complex _Float128") == 0)
> +	|| strcmp (name, "complex _Float128") == 0
> +	|| strcmp (name, "complex(kind=16)") == 0
> +	|| strcmp (name, "real(kind=16)") == 0)
>        return floatformats_ia64_quad;
>  
>    return default_floatformat_for_type (gdbarch, name, len);
> diff --git a/gdb/testsuite/gdb.fortran/complex.exp b/gdb/testsuite/gdb.fortran/complex.exp
> index 136f1c4df79..94ac53afc70 100644
> --- a/gdb/testsuite/gdb.fortran/complex.exp
> +++ b/gdb/testsuite/gdb.fortran/complex.exp
> @@ -33,7 +33,6 @@ gdb_test "print c4" " = \\(1000,-50\\)"
>  gdb_test "print c8" " = \\(321,-22\\)"
>  gdb_test "print dc" " = \\(321,-22\\)"
>  
> -setup_kfail gdb/18644 "*-*-*"
>  gdb_test "print c16" " = \\(-874,19\\)"
>  
>  gdb_test "whatis c" "type = complex\\(kind=4\\)"
> @@ -53,7 +52,6 @@ gdb_test "print \$_creal (dc)" " = 321"
>  gdb_test "whatis \$" " = real\\*8"
>  
>  gdb_test "whatis c16" "type = complex\\(kind=16\\)"
> -setup_kfail gdb/18644 "*-*-*"
>  gdb_test "print \$_creal (c16)" " = -874"
>  gdb_test "whatis \$" " = real\\*16"
>  
> diff --git a/gdb/testsuite/gdb.fortran/printing-types.exp b/gdb/testsuite/gdb.fortran/printing-types.exp
> index 2f6be4ec249..6394e45f4c3 100644
> --- a/gdb/testsuite/gdb.fortran/printing-types.exp
> +++ b/gdb/testsuite/gdb.fortran/printing-types.exp
> @@ -33,3 +33,4 @@ gdb_test "print oneByte"	" = 1"
>  gdb_test "print twobytes"	" = 2"
>  gdb_test "print chvalue"	" = \'a\'"
>  gdb_test "print logvalue"	" = \.TRUE\."
> +gdb_test "print rVal"		" = 2000"
> diff --git a/gdb/testsuite/gdb.fortran/printing-types.f90 b/gdb/testsuite/gdb.fortran/printing-types.f90
> index b4ff928604f..36b63532c8e 100644
> --- a/gdb/testsuite/gdb.fortran/printing-types.f90
> +++ b/gdb/testsuite/gdb.fortran/printing-types.f90
> @@ -18,10 +18,12 @@ program prog
>    integer(2) :: twoBytes
>    character  :: chValue
>    logical(1) :: logValue
> +  real(kind=16) :: rVal
>  
>    oneByte  = 1
>    twoBytes = 2
>    chValue  = 'a'
>    logValue = .true.
> +  rVal = 2000
>    write(*,*) s
>  end
> diff --git a/gdb/testsuite/gdb.fortran/type-kinds.exp b/gdb/testsuite/gdb.fortran/type-kinds.exp
> index 1ae15b96f1a..9d19a9ceb39 100644
> --- a/gdb/testsuite/gdb.fortran/type-kinds.exp
> +++ b/gdb/testsuite/gdb.fortran/type-kinds.exp
> @@ -27,12 +27,6 @@ if { [skip_fortran_tests] } { continue }
>  proc test_cast_1_to_type_kind {base_type type_kind cast_result size_result} {
>      set type_string "$base_type (kind=$type_kind)"
>      gdb_test "p (($type_string) 1)" " = $cast_result"
> -
> -    if {($base_type == "real" || $base_type == "complex")
> -	&& $type_kind == 16} {
> -	setup_kfail gdb/18644 "*-*-*"
> -    }
> -
>      gdb_test "p sizeof (($type_string) 1)" " = $size_result"
>  }
>  
> -- 
> 2.14.5
>