[PATCH] PR fortran/95502 - ICE in gfc_check_do_variable, at fortran/parse.c:4446

[Harald Anlauf via Gcc-patches]

ICE-on-invalid issues during error recovery.  Testcase by Gerhard,
initial patch by Steve.  I found another variant which needed an
additional fix for a NULL pointer dereference.

Regtested on x86_64-pc-linux-gnu.

OK for mainline / 11-branch?

Thanks,
Harald


Fortran - ICE in gfc_check_do_variable, at fortran/parse.c:4446

Avoid NULL pointer dereferences during error recovery.

gcc/fortran/ChangeLog:

        PR fortran/95502
        * expr.c (gfc_check_pointer_assign): Avoid NULL pointer
        dereference.
        * match.c (gfc_match_pointer_assignment): Likewise.
        * parse.c (gfc_check_do_variable): Avoid comparison with NULL
        symtree.

gcc/testsuite/ChangeLog:

        PR fortran/95502
        * gfortran.dg/pr95502.f90: New test.


diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index 956003ec605..b11ae7ce5c5 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -3815,6 +3815,9 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_expr *rvalue,
   int proc_pointer;
   bool same_rank;

+  if (!lvalue->symtree)
+    return false;
+
   lhs_attr = gfc_expr_attr (lvalue);
   if (lvalue->ts.type == BT_UNKNOWN && !lhs_attr.proc_pointer)
     {
diff --git a/gcc/fortran/match.c b/gcc/fortran/match.c
index 29462013038..d148de3e3b5 100644
--- a/gcc/fortran/match.c
+++ b/gcc/fortran/match.c
@@ -1409,7 +1409,7 @@ gfc_match_pointer_assignment (void)
   gfc_matching_procptr_assignment = 0;

   m = gfc_match (" %v =>", &lvalue);
-  if (m != MATCH_YES)
+  if (m != MATCH_YES || !lvalue->symtree)
     {
       m = MATCH_NO;
       goto cleanup;
diff --git a/gcc/fortran/parse.c b/gcc/fortran/parse.c
index 0522b391393..6d7845e8517 100644
--- a/gcc/fortran/parse.c
+++ b/gcc/fortran/parse.c
@@ -4588,6 +4588,9 @@ gfc_check_do_variable (gfc_symtree *st)
 {
   gfc_state_data *s;

+  if (!st)
+    return 0;
+
   for (s=gfc_state_stack; s; s = s->previous)
     if (s->do_variable == st)
       {
diff --git a/gcc/testsuite/gfortran.dg/pr95502.f90 b/gcc/testsuite/gfortran.dg/pr95502.f90
new file mode 100644
index 00000000000..d40fd9a5508
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr95502.f90
@@ -0,0 +1,8 @@
+! { dg-do compile }
+! PR fortran/95502 - ICE in gfc_check_do_variable, at fortran/parse.c:4446
+
+program p
+  integer, pointer :: z
+  nullify (z%kind)  ! { dg-error "in variable definition context" }
+  z%kind => NULL()  ! { dg-error "constant expression" }
+end