Ping [PATCHv3, gfortran] Escalate failure when Hollerith constant to real conversion fails [PR103628]

[HAO CHEN GUI <guihaoc@linux.ibm.com>]

Hi,
  Gently ping this:
  https://gcc.gnu.org/pipermail/gcc-patches/2023-March/613497.html

Thanks
Gui Haochen

在 2023/3/7 16:55, HAO CHEN GUI 写道:
> Hi,
>   The patch escalates the failure when Hollerith constant to real conversion
> fails in native_interpret_expr. It finally reports an "Cannot simplify
> expression" error in do_simplify method.
> 
>   The patch of pr95450 added a verification for decoding/encoding checking
> in native_interpret_expr. native_interpret_expr may fail on real type
> conversion and returns a NULL tree then. But upper layer calls don't handle
> the failure so that an ICE is reported when the verification fails.
> 
>   IBM long double is an example. It doesn't have a unique memory presentation
> for some real values. So it may not pass the verification. The new test
> case shows the problem.
> 
>   errorcount is used to check if an error is already reported or not when
> getting a bad expr. Buffered errors need to be excluded as they don't
> increase error count either.
> 
>   The patch passed regression test on Power and x86 linux platforms.
> 
> Gui Haochen
> Thanks
> 
> ChangeLog
> 2023-03-07  Haochen Gui <guihaoc@linux.ibm.com>
> 
> gcc/
> 	PR target/103628
> 	* fortran/target-memory.cc (gfc_interpret_float): Return FAIL when
> 	native_interpret_expr gets a NULL tree.
> 	* fortran/arith.cc (gfc_hollerith2real): Return NULL when
> 	gfc_interpret_float fails.
> 	* fortran/error.cc (gfc_buffered_p): Define.
> 	* fortran/gfortran.h (gfc_buffered_p): Declare.
> 	* fortran/intrinsic.cc: Add diagnostic.h to include list.
> 	(do_simplify): Save errorcount and check it at finish.  Report a
> 	"Cannot simplify expression" error on a bad result if error count
> 	doesn't change and no other errors buffered.
> 
> gcc/testsuite/
> 	PR target/103628
> 	* gfortran.dg/pr103628.f90: New.
> 
> Co-Authored-By: Tobias Burnus <tobias@codesourcery.com>
> 
> patch.diff
> diff --git a/gcc/fortran/arith.cc b/gcc/fortran/arith.cc
> index c0d12cfad9d..d3d38c7eb6a 100644
> --- a/gcc/fortran/arith.cc
> +++ b/gcc/fortran/arith.cc
> @@ -2752,10 +2752,12 @@ gfc_hollerith2real (gfc_expr *src, int kind)
>    result = gfc_get_constant_expr (BT_REAL, kind, &src->where);
> 
>    hollerith2representation (result, src);
> -  gfc_interpret_float (kind, (unsigned char *) result->representation.string,
> -		       result->representation.length, result->value.real);
> -
> -  return result;
> +  if (gfc_interpret_float (kind,
> +			   (unsigned char *) result->representation.string,
> +			   result->representation.length, result->value.real))
> +    return result;
> +  else
> +    return NULL;
>  }
> 
>  /* Convert character to real.  The constant will be padded or truncated.  */
> diff --git a/gcc/fortran/error.cc b/gcc/fortran/error.cc
> index 214fb78ba7b..872d42e731e 100644
> --- a/gcc/fortran/error.cc
> +++ b/gcc/fortran/error.cc
> @@ -49,6 +49,13 @@ static gfc_error_buffer error_buffer;
>  static output_buffer *pp_error_buffer, *pp_warning_buffer;
>  static int warningcount_buffered, werrorcount_buffered;
> 
> +/* Return buffered_p.  */
> +bool
> +gfc_buffered_p (void)
> +{
> +  return buffered_p;
> +}
> +
>  /* Return true if there output_buffer is empty.  */
> 
>  static bool
> diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
> index 219ef8c7612..edfe11796a6 100644
> --- a/gcc/fortran/gfortran.h
> +++ b/gcc/fortran/gfortran.h
> @@ -3328,6 +3328,7 @@ void gfc_internal_error (const char *, ...) ATTRIBUTE_NORETURN ATTRIBUTE_GCC_GFC
>  void gfc_clear_error (void);
>  bool gfc_error_check (void);
>  bool gfc_error_flag_test (void);
> +bool gfc_buffered_p (void);
> 
>  notification gfc_notification_std (int);
>  bool gfc_notify_std (int, const char *, ...) ATTRIBUTE_GCC_GFC(2,3);
> diff --git a/gcc/fortran/intrinsic.cc b/gcc/fortran/intrinsic.cc
> index e89131f5a71..9d049001a51 100644
> --- a/gcc/fortran/intrinsic.cc
> +++ b/gcc/fortran/intrinsic.cc
> @@ -25,6 +25,7 @@ along with GCC; see the file COPYING3.  If not see
>  #include "options.h"
>  #include "gfortran.h"
>  #include "intrinsic.h"
> +#include "diagnostic.h" /* For errorcount.  */
> 
>  /* Namespace to hold the resolved symbols for intrinsic subroutines.  */
>  static gfc_namespace *gfc_intrinsic_namespace;
> @@ -4620,6 +4621,7 @@ do_simplify (gfc_intrinsic_sym *specific, gfc_expr *e)
>  {
>    gfc_expr *result, *a1, *a2, *a3, *a4, *a5, *a6;
>    gfc_actual_arglist *arg;
> +  int old_errorcount = errorcount;
> 
>    /* Max and min require special handling due to the variable number
>       of args.  */
> @@ -4708,7 +4710,12 @@ do_simplify (gfc_intrinsic_sym *specific, gfc_expr *e)
> 
>  finish:
>    if (result == &gfc_bad_expr)
> -    return false;
> +    {
> +      if (errorcount == old_errorcount
> +	  && (gfc_buffered_p () && !gfc_error_flag_test ()))
> +       gfc_error ("Cannot simplify expression at %L", &e->where);
> +      return false;
> +    }
> 
>    if (result == NULL)
>      resolve_intrinsic (specific, e);	/* Must call at run-time */
> diff --git a/gcc/fortran/target-memory.cc b/gcc/fortran/target-memory.cc
> index 7ce7d736629..0c47aa6b842 100644
> --- a/gcc/fortran/target-memory.cc
> +++ b/gcc/fortran/target-memory.cc
> @@ -416,11 +416,14 @@ gfc_interpret_float (int kind, unsigned char *buffer, size_t buffer_size,
>  		     mpfr_t real)
>  {
>    gfc_set_model_kind (kind);
> -  mpfr_init (real);
> -  gfc_conv_tree_to_mpfr (real,
> -			 native_interpret_expr (gfc_get_real_type (kind),
> -						buffer, buffer_size));
> 
> +  tree source = native_interpret_expr (gfc_get_real_type (kind), buffer,
> +				       buffer_size);
> +  if (!source)
> +    return 0;
> +
> +  mpfr_init (real);
> +  gfc_conv_tree_to_mpfr (real, source);
>    return size_float (kind);
>  }
> 
> diff --git a/gcc/testsuite/gfortran.dg/pr103628.f90 b/gcc/testsuite/gfortran.dg/pr103628.f90
> new file mode 100644
> index 00000000000..255d5bdd73e
> --- /dev/null
> +++ b/gcc/testsuite/gfortran.dg/pr103628.f90
> @@ -0,0 +1,14 @@
> +! { dg-do compile { target powerpc*-*-* } }
> +! { dg-options "-O2 -mabi=ibmlongdouble" }
> +
> +! Test to ensure that it reports an "Cannot simplify expression" error
> +! instead of throwing an ICE when the memory represent of the HOLLERITH
> +! string is not unique with ibm long double encoding.
> +
> +program main
> +  integer, parameter :: k = 16
> +  real(kind = k):: b = 4h1234
> +end program main
> +
> +! { dg-warning "Conversion from HOLLERITH" "warning" { target powerpc*-*-* } 10 }
> +! { dg-error "Cannot simplify expression" "error" { target powerpc*-*-* } 10 }
>