[gcc r12-5136] Fortran: avoid NULL pointer dereferences

[Harald Anlauf <anlauf@gcc.gnu.org>]

https://gcc.gnu.org/g:abc2f01914d6c4703de26c402fb579a9a2d0dba4

commit r12-5136-gabc2f01914d6c4703de26c402fb579a9a2d0dba4
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Wed Nov 10 20:30:27 2021 +0100

    Fortran: avoid NULL pointer dereferences
    
    CLASS(), PARAMETER is not yet properly implemented in gfortran.  Using it
    in declarations could lead to subsequent NULL pointer dereferences during
    checking or simplification of expressions involving those CLASS variables.
    
    gcc/fortran/ChangeLog:
    
            PR fortran/103137
            PR fortran/103138
            * check.c (gfc_check_shape): Avoid NULL pointer dereference on
            missing ref.
            * simplify.c (gfc_simplify_cshift): Avoid NULL pointer dereference
            when shape not set.
            (gfc_simplify_transpose): Likewise.

Diff:
---
 gcc/fortran/check.c    | 3 +++
 gcc/fortran/simplify.c | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/gcc/fortran/check.c b/gcc/fortran/check.c
index 15772009af4..ffa07b510cd 100644
--- a/gcc/fortran/check.c
+++ b/gcc/fortran/check.c
@@ -5096,6 +5096,9 @@ gfc_check_shape (gfc_expr *source, gfc_expr *kind)
   if (source->rank == 0 || source->expr_type != EXPR_VARIABLE)
     return true;
 
+  if (source->ref == NULL)
+    return false;
+
   ar = gfc_find_array_ref (source);
 
   if (ar->as && ar->as->type == AS_ASSUMED_SIZE && ar->type == AR_FULL)
diff --git a/gcc/fortran/simplify.c b/gcc/fortran/simplify.c
index d675f2c3aef..6a6b3fbd037 100644
--- a/gcc/fortran/simplify.c
+++ b/gcc/fortran/simplify.c
@@ -2109,6 +2109,9 @@ gfc_simplify_cshift (gfc_expr *array, gfc_expr *shift, gfc_expr *dim)
   else
     which = 0;
 
+  if (array->shape == NULL)
+    return NULL;
+
   gfc_array_size (array, &size);
   arraysize = mpz_get_ui (size);
   mpz_clear (size);
@@ -8174,6 +8177,9 @@ gfc_simplify_transpose (gfc_expr *matrix)
 
   gcc_assert (matrix->rank == 2);
 
+  if (matrix->shape == NULL)
+    return NULL;
+
   result = gfc_get_array_expr (matrix->ts.type, matrix->ts.kind,
 			       &matrix->where);
   result->rank = 2;