[Patch, fortran] PR82934 - [6/7/8 Regression] Segfault on assumed character length in allocate

[Paul Richard Thomas]

Committed as obvious in r254624.

I will apply to 6- and 7-branches over the weekend. Although not a
regression, the fix prevents an ICE in a particularly robust way.

Cheers

Paul

2017-11-10  Paul Thomas  <pa...@gcc.gnu.org>

    PR fortran/82934
    * trans-stmt.c (gfc_trans_allocate): Remove the gcc_assert on
    null string length for assumed length typespec and set
    expr3_esize to NULL_TREE;

2017-11-10  Paul Thomas  <pa...@gcc.gnu.org>

    PR fortran/82934
    * gfortran.dg/allocate_assumed_charlen_1.f90: New test.

Index: gcc/fortran/trans-stmt.c
===================================================================
*** gcc/fortran/trans-stmt.c    (revision 254604)
--- gcc/fortran/trans-stmt.c    (working copy)
*************** gfc_trans_allocate (gfc_code * code)
*** 5913,5922 ****
        if (code->ext.alloc.ts.type != BT_CHARACTER)
        expr3_esize = TYPE_SIZE_UNIT (
              gfc_typenode_for_spec (&code->ext.alloc.ts));
!       else
        {
          gfc_expr *sz;
-         gcc_assert (code->ext.alloc.ts.u.cl->length != NULL);
          sz = gfc_copy_expr (code->ext.alloc.ts.u.cl->length);
          gfc_init_se (&se_sz, NULL);
          gfc_conv_expr (&se_sz, sz);
--- 5913,5921 ----
        if (code->ext.alloc.ts.type != BT_CHARACTER)
        expr3_esize = TYPE_SIZE_UNIT (
              gfc_typenode_for_spec (&code->ext.alloc.ts));
!       else if (code->ext.alloc.ts.u.cl->length != NULL)
        {
          gfc_expr *sz;
          sz = gfc_copy_expr (code->ext.alloc.ts.u.cl->length);
          gfc_init_se (&se_sz, NULL);
          gfc_conv_expr (&se_sz, sz);
*************** gfc_trans_allocate (gfc_code * code)
*** 5930,5935 ****
--- 5929,5936 ----
                                         tmp, se_sz.expr);
          expr3_esize = gfc_evaluate_now (expr3_esize, &block);
        }
+       else
+       expr3_esize = NULL_TREE;
      }
  
    /* The routine gfc_trans_assignment () already implements all
Index: gcc/testsuite/gfortran.dg/allocate_assumed_charlen_1.f90
===================================================================
*** gcc/testsuite/gfortran.dg/allocate_assumed_charlen_1.f90    (nonexistent)
--- gcc/testsuite/gfortran.dg/allocate_assumed_charlen_1.f90    (working copy)
***************
*** 0 ****
--- 1,28 ----
+ ! { dg-do run }
+ !
+ ! PR82934: Segfault on compilation in trans-stmt.c:5919(8.0.0).
+ ! The original report only had one item in the allocate list. This
+ ! has been doubled up to verify that the correct string length is
+ ! is used in the allocation.
+ !
+ ! Contributed by FortranFan on clf.
+ !
+    character(len=42), allocatable :: foo
+    character(len=22), allocatable :: foofoo
+ 
+    call alloc( foo , foofoo)
+ 
+    if (len(foo) .ne. 42) call abort
+    if (len(foofoo) .ne. 22) call abort
+ 
+ contains
+ 
+    subroutine alloc( bar, barbar )
+ 
+       character(len=*), allocatable :: bar, barbar
+ 
+       allocate( character(len=*) :: bar , barbar) ! <= Here!
+ 
+    end subroutine
+ 
+ end