Re: Patch for fortran/62536 and fortran/66175

[FX <fxcoudert@gmail.com>]

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> This patch cleans up nested blocks when there's an unexpected end of a compilation unit (66175), and it handles cleaned-up blocks gracefully (62536).  I've run "make check-fortran" with the attached test cases.

I have now committed the patch to trunk as revision 227135.
Thanks for your contribution! And you’re welcome to repeat that experience anytime :)

FYI, I fixed a few minor issues with the patch before committed it (final version attached):
  - test directive should be { dg-do compile } not { dg-compile }
  - comment reformatting
  - missing gcc/testsuite/ChangeLog entries
  - reformated date and PR entries in ChangeLog


Thanks again,
FX


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Index: gcc/fortran/ChangeLog
===================================================================
--- gcc/fortran/ChangeLog	(revision 227134)
+++ gcc/fortran/ChangeLog	(working copy)
@@ -1,3 +1,11 @@
+2015-08-24  Louis Krupp <louis.krupp@zoho.com>
+
+	PR fortran/62536
+	PR fortran/66175
+	* decl.c (gfc_match_end): Clean up nested BLOCKs.
+	* parse.c (parse_block_construct): Deal gracefully with cleaned-up
+	BLOCKs.
+
 2015-08-23  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	PR libfortran/54572
Index: gcc/fortran/decl.c
===================================================================
--- gcc/fortran/decl.c	(revision 227127)
+++ gcc/fortran/decl.c	(working copy)
@@ -6483,7 +6483,7 @@ cleanup:
   /* If we are missing an END BLOCK, we created a half-ready namespace.
      Remove it from the parent namespace's sibling list.  */
 
-  if (state == COMP_BLOCK)
+  while (state == COMP_BLOCK)
     {
       parent_ns = gfc_current_ns->parent;
 
@@ -6506,6 +6506,8 @@ cleanup:
   
       gfc_free_namespace (gfc_current_ns);
       gfc_current_ns = parent_ns;
+      gfc_state_stack = gfc_state_stack->previous;
+      state = gfc_current_state ();
     }
 
   return MATCH_ERROR;
Index: gcc/fortran/parse.c
===================================================================
--- gcc/fortran/parse.c	(revision 227127)
+++ gcc/fortran/parse.c	(working copy)
@@ -3935,6 +3935,7 @@ static void
 parse_block_construct (void)
 {
   gfc_namespace* my_ns;
+  gfc_namespace* my_parent;
   gfc_state_data s;
 
   gfc_notify_std (GFC_STD_F2008, "BLOCK construct at %C");
@@ -3948,10 +3949,14 @@ parse_block_construct (void)
 
   push_state (&s, COMP_BLOCK, my_ns->proc_name);
   gfc_current_ns = my_ns;
+  my_parent = my_ns->parent;
 
   parse_progunit (ST_NONE);
 
-  gfc_current_ns = gfc_current_ns->parent;
+  /* Don't depend on the value of gfc_current_ns;  it might have been
+     reset if the block had errors and was cleaned up.  */
+  gfc_current_ns = my_parent;
+
   pop_state ();
 }
 
Index: gcc/testsuite/ChangeLog
===================================================================
--- gcc/testsuite/ChangeLog	(revision 227134)
+++ gcc/testsuite/ChangeLog	(working copy)
@@ -1,3 +1,10 @@
+2015-08-24  Louis Krupp <louis.krupp@zoho.com>
+
+	PR fortran/62536
+	PR fortran/66175
+	* gfortran.dg/block_end_error_1.f90: New test.
+	* gfortran.dg/blocks_nested_incomplete_1.f90: New test.
+
 2015-08-24  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/66821
Index: gcc/testsuite/gfortran.dg/block_end_error_1.f90
===================================================================
--- gcc/testsuite/gfortran.dg/block_end_error_1.f90	(revision 0)
+++ gcc/testsuite/gfortran.dg/block_end_error_1.f90	(working copy)
@@ -0,0 +1,10 @@
+! { dg-do compile }
+!
+! PR fortran/62536
+! Bad "end block" causes ICE.
+subroutine s
+   block
+   end block named ! { dg-error "Syntax error in END BLOCK statement" }
+   return
+endsubroutine
+! { dg-prune-output "Unexpected end of file" }
Index: gcc/testsuite/gfortran.dg/blocks_nested_incomplete_1.f90
===================================================================
--- gcc/testsuite/gfortran.dg/blocks_nested_incomplete_1.f90	(revision 0)
+++ gcc/testsuite/gfortran.dg/blocks_nested_incomplete_1.f90	(working copy)
@@ -0,0 +1,9 @@
+! { dg-do compile }
+!
+! PR fortran/66175
+! Nested incomplete blocks cause ICE.
+program main
+  block
+    block
+end program ! { dg-error "Expecting END BLOCK statement" }
+! { dg-prune-output "Unexpected end of file" }