This change enables warnings for mutual recursion for the low level C
backend.
--warn-non-tail-recursion currently only works for direct recursion. This
change renames it to --warn-non-tail-recursion-self and adds
--warn-non-tail-recursion which is intended to produce warnings for self
and mutual recursion.
compiler/options.m:
Add new option.
compiler/handle_options.m:
Make --warn-non-tail-recursion imply --warn-non-tail-recursion-self.
compiler/ml_tailcall.m:
Conform to changes in options.m.
compiler/mark_tail_calls.m:
Simplify the code that interprets tail recursion warning options, this
avoids the need for the warn_non_tail_rec_calls_opt which was only used
here in an unnecessary step. This logic has also been moved to a
separate predicate.
Add a warning for mutually recursive calls that are not tail recursive.
Update these warning/error messages to say if the call is self or
mutually recursive. Also in the case of mutually recursive calls, name
the callee.
compiler/mercury_compile_llds_back_end.m:
Compute the dependency information before running the pre-LLDS passes.
This makes sure that we do this once for the whole module, and
independently of --trad-passes.
compiler/dependency_graph.m:
Add a method for getting the SCC of a given node from a dependency_info
structure. The SCC is retrieved from a lazily built map.
doc/user_guide.texi:
Document the changes.
tests/invalid/Mmakefile:
tests/invalid/require_tailrec_1.err_exp:
tests/invalid/require_tailrec_1.m:
tests/invalid/require_tailrec_2.err_exp:
tests/invalid/require_tailrec_2.m:
tests/invalid/require_tailrec_3.err_exp:
tests/invalid/require_tailrec_3.m:
tests/valid/Mmakefile:
tests/valid/require_tailrec_1.m:
tests/valid/require_tailrec_2.m:
tests/valid/require_tailrec_3.m:
Test the tail recursion warnings a lot more extensively, some of these
are new test programs, others just have many more test cases within
them.
tests/invalid/Mercury.options:
tests/valid/Mercury.options:
Add new test files.
Disable most optimisations as these could optimise away the mutual tail
recursions.
tests/EXPECT_FAIL_TESTS.hlc.gc:
New test case failures.
