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.
This patch reduces spurious tail call warnings by warning only for the last
of a sequence of recursive calls along an execution path, for example it
no-longer emits a warning for the first of the two recursive calls in
quicksort. I have already made a change to this effect for the MLDS
backends.
This patch also implements the new the require_tail_recursion pragma. This
change has already been made for the MLDS backends.
The require_tail_recursion pragma does not yet handle mutual recursion or
raise an error if the code is not recursive at all. These will be my next
tasks.
compiler/mark_tail_calls.m:
Combine marking tail calls with warning about tail calls.
Handle scopes more accurately.
compiler/mercury_compile_llds_back_end.m:
Conform to changes in mark_tail_calls.m
No longer warn for tail calls, this is now done in the same pass that
marks tail calls. The decision to run this pass is now made on a
per-procedure basis and in mark_tail_calls.m
tests/invalid/require_tailrec_1.m:
tests/invalid/require_tailrec_2.m:
tests/invalid/Mmakefile:
tests/invalid/Mercury.options:
tests/valid/require_tailrec_1.m:
tests/valid/require_tailrec_2.m:
tests/valid/Mmakefile:
tests/valid/Mercury.options:
Add new tests.
tests/invalid/Mmakefile:
tests/invalid/Mercury.options:
tests/invalid/require_tail_recursion.{m,err_exp} ->
require_tailrec_invalid.{m,exp}:
Rename existing test.
