Fortran FINALization

This directory contains some draft patches to implement support for FINAL subroutines

Status as of 2013-05-31 on the 4.9 trunk

Supported by the patches in this directory

• The finalization is invoked for DEALLOCATE, end of scope, for INTENT(OUT) and MOVE_ALLOC [some issues remain, cf. below]
• Basic implementation works.

UPDATE 2013-05-28

PATCHES: Enable FINAL infrastructure, but no finalization is done yet

• Patch: Enable wrapper generation, http://gcc.gnu.org/ml/fortran/2013-05/msg00073.html
• Patch: Enable FINAL parsing, http://gcc.gnu.org/ml/fortran/2013-05/msg00094.html

Work in progress:

• finalize-allocatables-2013-05-27.diff adds finalization for allocatables. See patch for remaining tasks.
• Additional tasks: Ensure that the other callers of gfc_trans_dealloc_allocated finalize when possible (requires expr); ditto for gfc_deallocate_scalar_with_status. Main work item is the deallocation of components.

Pending issues:

• See old 2013-03-31 patch for some additional features (needs to be rediffed).
• TODO: End of scope handling for polymorphic allocatables. Refactor deallocate functions.
• TODO: Cleanup of the current patch
• See below for additional to-do items.

UPDATE 2013-05-27

• Committed: Patch: Poly array intent(out) deallocation, http://gcc.gnu.org/ml/fortran/2013-05/msg00081.html

UPDATE 2013-03-31

• Bugfixes merged to the trunk.
• See latest patch, which includes a first test case and no test suite failures.
• TODO: Fix finalization for arrays with INTENT(OUT), array CLASS: Fix end-of-scope dealloc+finalize
• Major cleanup of the code, more test cases, also to show polymorphic deallocate.
• Add end of scope finalization for nonallocatables (also for components) and add test cases for it.
• Fix OPTIONAL/ELEMENTAL handling
• See other possible TODO items below

UPDATE 2013-03-25

• Rediff, some bug fixes, first test case (see bugs in the test case)
• TODO: Call FINAL for allocatable intent(out) in the caller (no longer calling in the callee).
• See 2013-02-17 for additional TODO items

UPDATE 2013-02-17

• Rediff and fix a couple of bugs
• No test-suite failures
• WARNING: FINAL subroutines are mishandled for ALLOCATABLE dummys with INTENT(OUT) as they are already deallocated in trans-expr.c before the call while the current patch handles them via trans-decl.c in the callee.
• TODO: Testing and add test cases en mass; checking for issues with OPTIONAL, ELEMENTAL etc. (cf. PR54618), allocatable components (esp. coarray ones), handling deallocation failures with coarrays ?, plugging memory leaks in the compiler itself; invoking code for the finalizer (for nonallocatables, compontents, assignments [also with sections/vector subscripts]); check that calling assumed-size/explicit-size finalization subroutines works for packed and nonpacked arrays, …

UPDATE 2013-01-05

• The wrapper patch has been committed. Now only calls to the wrapper have to be inserted.
• See today's patch for a start.
• See 2012-12-29 for a to-do list.

UPDATE 2012-12-31

• Submitted patches, fixing the remaing issues for the wrapper; another auxiliary function.
• Missing: Actual calls to the wrapper. (The patch on this page contains some.)
• See 2012-12-29 for a to-do list.

UPDATE 2012-12-30

• See 2012-12-29.
• Preparations for stride support (noncontiguous arrays).

UPDATE 2012-12-29

• Support for CLASS(*), no test-suite failures.
• Internal _.F_stride function, fixes in invoking the final wrapper.
• Main remaining issue: Supporting arrays with stride (e.g. assumed-shape intent-out arrays). Requires an update of the scalarizer and package code in the final wrapper, using the _F.stride function.
• Other to-do items: Testing, test-case writting, checking for issues with OPTIONAL, ELEMENTAL etc. (cf. PR54618), allocatable components (esp. coarray ones), handling deallocation failures with coarrays ?, plugging memory leaks in the compiler itself; invoking code for the finalizer (for nonallocatables, compontents, assignments [also with sections/vector subscripts]); check that calling assumed-size/explicit-size finalization subroutines works for packed and nonpacked arrays, …

UPDATE 2012-12-03

• The FINAL wrapper should be now complete.
• TODO 1: Continue merging Janus's 2012-11-04 patch, including test-case fixes; clean up of the current patch
• TODO 2: Fix issues mentioned in the old patch thread and on this page.

UPDATE 2012-11-27

• Current patch based on the 2012-10-26 patch
• It does not contain the changes of the 2012-11-04 patch
• Changes compared to 2012-10-26:
  • Pass stride to the wrapper - avoid unnecessary repacking (which is also not implemented)
  • INCOMPLETE: Packing of the arrays when calling array finalization subroutines
  • Coarray fixes: Scalar corrays don't ICE, coarrays are only finalized if fini_coarray is true
• Short-term TODO: Finish incomplete part, fix some of the smaller issues mentioned below and incorporate the changes of the 2012-11-04 patch

Still to be done

• Handle CLASS(*)
• Check that scope-leaving variables which aren't allocatable are properly finalized.
• For intent(out), adapt OPTIONAL (ALLOCATABLE) NULL check after PR54618 has been fixed.
• Don't add the vtab->_final == NULL check if the declared type is known to have a non-null finalizer.
• Assumed-rank arrays: Packing support when passing a noncontiguous array to CONTIGUOUS dummy (to be used for calling the parent's wrapper procedure)
• Allocatable components – especially intrinsic assignment with coarray components (Unrelated to FINAL but also needed: deregister calls for coarray components)
• For allocatable coarray components: Handle STAT_STOPPED_IMAGE for DEALLOCATE
• Too much finalization: Variables in the main program are finalized, but shouldn't. (Are other implicitly/explicitly SAVEd vars also affected?)
• Clean up and refactoring of the patch
• The current version leaks quite a lot of memory, e.g. in generate_finalization_wrapper in the call to gfc_lval_expr_from_sym at

            finalize_component (gfc_lval_expr_from_sym (ptr), derived, comp,
                                gfc_lval_expr_from_sym (stat), &block);
  

• New test cases, fix tree-scan-counts.

Fixed in 2012-09-18

• All regression-suite failures (except of the tree-scan-times ones)
• For CLASS(...),INTENT(OUT), no vtab->_final == NULL check is generated if it is known to be non-NULL. (Still to be done at other parts of the code)

Fixed in 2012-09-11

• Fix class.c's ts.interface for EXPR_NULL - otherwise one gets in trouble for CLASS
• Some test suite and FINAL test case fixes