Re: [PATCH 3/3] Fortran: Fix mpz and mpfr memory leaks

[Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>]

On 3 April 2023 21:50:49 CEST, Harald Anlauf <anlauf@gmx.de> wrote:
>Hi Bernhard,
>
>there is neither context nor a related PR with a testcase showing
>that this patch fixes issues seen there.

Yes, i forgot to mention the PR:

PR fortran/68800

I did not construct individual test cases but it should be obvious that we should not leak these.

>
>On 4/2/23 17:05, Bernhard Reutner-Fischer via Gcc-patches wrote:
>> From: Bernhard Reutner-Fischer <aldot@gcc.gnu.org>
>> 
>> Cc: fortran@gcc.gnu.org
>> 
>> gcc/fortran/ChangeLog:
>> 
>> 	* array.cc (gfc_ref_dimen_size): Free mpz memory before ICEing.
>> 	* expr.cc (find_array_section): Fix mpz memory leak.
>> 	* simplify.cc (gfc_simplify_reshape): Fix mpz memory leaks in
>> 	error paths.
>> 	(gfc_simplify_set_exponent): Fix mpfr memory leak.
>> ---
>>   gcc/fortran/array.cc    | 3 +++
>>   gcc/fortran/expr.cc     | 8 ++++----
>>   gcc/fortran/simplify.cc | 7 ++++++-
>>   3 files changed, 13 insertions(+), 5 deletions(-)
>> 
>> diff --git a/gcc/fortran/array.cc b/gcc/fortran/array.cc
>> index be5eb8b6a0f..8b1e816a859 100644
>> --- a/gcc/fortran/array.cc
>> +++ b/gcc/fortran/array.cc
>> @@ -2541,6 +2541,9 @@ gfc_ref_dimen_size (gfc_array_ref *ar, int dimen, mpz_t *result, mpz_t *end)
>>         return t;
>> 
>>       default:
>> +      mpz_clear (lower);
>> +      mpz_clear (stride);
>> +      mpz_clear (upper);
>>         gfc_internal_error ("gfc_ref_dimen_size(): Bad dimen_type");
>>       }
>
>What is the point of clearing variables before issuing a gfc_internal_error?

To make it obvious that we are aware that we allocated these.

thanks,
>
>> diff --git a/gcc/fortran/expr.cc b/gcc/fortran/expr.cc
>> index 7fb33f81788..b4736804eda 100644
>> --- a/gcc/fortran/expr.cc
>> +++ b/gcc/fortran/expr.cc
>> @@ -1539,6 +1539,7 @@ find_array_section (gfc_expr *expr, gfc_ref *ref)
>>     mpz_init_set_ui (delta_mpz, one);
>>     mpz_init_set_ui (nelts, one);
>>     mpz_init (tmp_mpz);
>> +  mpz_init (ptr);
>> 
>>     /* Do the initialization now, so that we can cleanup without
>>        keeping track of where we were.  */
>> @@ -1682,7 +1683,6 @@ find_array_section (gfc_expr *expr, gfc_ref *ref)
>>         mpz_mul (delta_mpz, delta_mpz, tmp_mpz);
>>       }
>> 
>> -  mpz_init (ptr);
>>     cons = gfc_constructor_first (base);
>> 
>>     /* Now clock through the array reference, calculating the index in
>> @@ -1735,7 +1735,8 @@ find_array_section (gfc_expr *expr, gfc_ref *ref)
>>   		     "at %L requires an increase of the allowed %d "
>>   		     "upper limit.  See %<-fmax-array-constructor%> "
>>   		     "option", &expr->where, flag_max_array_constructor);
>> -	  return false;
>> +	  t = false;
>> +	  goto cleanup;
>>   	}
>> 
>>         cons = gfc_constructor_lookup (base, limit);
>> @@ -1750,8 +1751,6 @@ find_array_section (gfc_expr *expr, gfc_ref *ref)
>>   				   gfc_copy_expr (cons->expr), NULL);
>>       }
>> 
>> -  mpz_clear (ptr);
>> -
>>   cleanup:
>> 
>>     mpz_clear (delta_mpz);
>> @@ -1765,6 +1764,7 @@ cleanup:
>>         mpz_clear (ctr[d]);
>>         mpz_clear (stride[d]);
>>       }
>> +  mpz_clear (ptr);
>>     gfc_constructor_free (base);
>>     return t;
>>   }
>> diff --git a/gcc/fortran/simplify.cc b/gcc/fortran/simplify.cc
>> index ecf0e3558df..d1f06335e79 100644
>> --- a/gcc/fortran/simplify.cc
>> +++ b/gcc/fortran/simplify.cc
>> @@ -6866,6 +6866,7 @@ gfc_simplify_reshape (gfc_expr *source, gfc_expr *shape_exp,
>>   	  gfc_error ("The SHAPE array for the RESHAPE intrinsic at %L has a "
>>   		     "negative value %d for dimension %d",
>>   		     &shape_exp->where, shape[rank], rank+1);
>> +	  mpz_clear (index);
>>   	  return &gfc_bad_expr;
>>   	}
>> 
>> @@ -6889,6 +6890,7 @@ gfc_simplify_reshape (gfc_expr *source, gfc_expr *shape_exp,
>>   	{
>>   	  gfc_error ("Shapes of ORDER at %L and SHAPE at %L are different",
>>   		     &order_exp->where, &shape_exp->where);
>> +	  mpz_clear (index);
>>   	  return &gfc_bad_expr;
>>   	}
>> 
>> @@ -6902,6 +6904,7 @@ gfc_simplify_reshape (gfc_expr *source, gfc_expr *shape_exp,
>>   	{
>>   	  gfc_error ("Sizes of ORDER at %L and SHAPE at %L are different",
>>   		     &order_exp->where, &shape_exp->where);
>> +	  mpz_clear (index);
>>   	  return &gfc_bad_expr;
>>   	}
>> 
>> @@ -6918,6 +6921,7 @@ gfc_simplify_reshape (gfc_expr *source, gfc_expr *shape_exp,
>>   			 "in the range [1, ..., %d] for the RESHAPE intrinsic "
>>   			 "near %L", order[i], &order_exp->where, rank,
>>   			 &shape_exp->where);
>> +	      mpz_clear (index);
>>   	      return &gfc_bad_expr;
>>   	    }
>> 
>> @@ -6926,6 +6930,7 @@ gfc_simplify_reshape (gfc_expr *source, gfc_expr *shape_exp,
>>   	    {
>>   	      gfc_error ("ORDER at %L is not a permutation of the size of "
>>   			 "SHAPE at %L", &order_exp->where, &shape_exp->where);
>> +	      mpz_clear (index);
>>   	      return &gfc_bad_expr;
>>   	    }
>>   	  x[order[i]] = 1;
>> @@ -7408,7 +7413,7 @@ gfc_simplify_set_exponent (gfc_expr *x, gfc_expr *i)
>>     exp2 = (unsigned long) mpz_get_d (i->value.integer);
>>     mpfr_mul_2exp (result->value.real, frac, exp2, GFC_RND_MODE);
>> 
>> -  mpfr_clears (absv, log2, pow2, frac, NULL);
>> +  mpfr_clears (exp, absv, log2, pow2, frac, NULL);
>> 
>>     return range_check (result, "SET_EXPONENT");
>>   }
>