Violation of C standard detected by clang -fsanitize=undefined
with clang 19.1.7 on Fedora 41 x86-64.
* src/counterexample.c (si_bfs_free):
* src/files.c (prefix_map_free, add_prefix_map):
* src/fixits.c (fixit_cmp, fixit_free, fixits_register):
(expand_to_conflict, nonunifying_shift_path)
(search_state_free_children, search_state_free, ssb_free)
(ssb_hasher, ssb_comp, ssb_equals, visited_hasher)
(visited_comparator, ssb_append, unifying_example):
* src/lssi.c (lssi_free, lssi_hasher, lssi_comparator)
(shortest_path_from_start):
* src/parse-simulation.c (free_parse_state)
(parse_state_list_new, parser_pop):
* src/state-item.c (hash_pair_hasher, hash_pair_comparator)
(hash_pair_free, hash_pair_table_create):
Avoid undefined behavior in C, which does not allow you to cast a
function pointer to some other function type and then call it via
that other type. Instead, use functions with correct types
according to the C standard, and cast their parameters.
* src/getargs.c (xargmatch_fn): Return int const, not int, to
match what ARGMATCH_DEFINE_GROUP does. In all uses of
ARGMATCH_DEFINE_GROUP, say that they return int, to match
xargmatch_fn.
(FLAGS_ARGMATCH): Do not cast function pointer.
* src/parse-simulation.c (vc_derivation_list_append): New function.
* src/system.h (deconst): New static function.
Older versions of GCC (4.1.2 here) don't like repeated typedefs.
CC src/bison-parse-simulation.o
src/parse-simulation.c:61: error: redefinition of typedef 'parse_state'
src/parse-simulation.h:74: error: previous declaration of 'parse_state' was here
make: *** [Makefile:7876: src/bison-parse-simulation.o] Error 1
Reported by Nelson H. F. Beebe.
* src/parse-simulation.c (parse_state): Don't typedef,
parse-simulation.h did it already.
* src/counterexample.c, src/parse-simulation.c: It is more usual in
Bison to use sizeof on expressions than on types, especially for
allocation.
Let the compiler do it's job instead of calling memcpy ourselves.
There are too many gl_list_t in there, it's hard to understand what is
going on. Introduce and use more precise types. I sure can be wrong
in some places, it's hard to tell without proper tool support.
* src/counterexample.c, src/lssi.c, src/lssi.h, src/parse-simulation.c,
* src/parse-simulation.h, src/state-item.c, src/state-item.h
(si_bfs_node_list, search_state_list, ssb_list, lssi_list)
(state_item_list): New.
Prefer `&foos[i]` to `foos + i` when `foos` is an array. IMHO, it
makes the semantics clearer.
* src/counterexample.c, src/lssi.c, src/parse-simulation.c,
* src/state-item.c: With arrays, prefer the array notation rather than
the pointer one.
I implemented this to print A ::= [ ], but A ::= [ %empty ] might be
clearer.
* src/parse-simulation.c (nullable_closure): Don't generate null
nonterminal derivations as leaves.
* src/derivation.c (derivation_print_impl): Don't print seperator
spaces for null nonterminal.
* tests/counterexample.at: Update test results.
First, we should avoid code such as
gl_list_iterator_t it = gl_list_iterator (deriv->children);
derivation *child = NULL;
while (gl_list_iterator_next (&it, (const void **) &child, NULL))
{
derivation_print (child, f);
because of -Wstrict-aliasing (whose job is to catch type-punning
issues). See https://lists.gnu.org/r/bug-bison/2020-05/msg00039.html.
Rather we need
gl_list_iterator_t it = gl_list_iterator (deriv->children);
const void **p = NULL;
while (gl_list_iterator_next (&it, &p, NULL))
{
derivation *child = (derivation *) p;
derivation_print (child, f);
Second, list iterators actually have destructors. Even though they
are noop in the case of linked-lists, we should use them.
Let's address both issues with typed wrappers (such as
derivation_list_next) that take care of both issues, and besides allow
to scope the iterators within the loop:
derivation *child;
for (gl_list_iterator_t it = gl_list_iterator (deriv->children);
derivation_list_next (&it, &child);
)
{
derivation_print (child, f);
* src/derivation.h, src/derivation.c (derivation_list_next): New.
Use it where appropriate.
* src/counterexample.c (search_state_list_next): New.
Use it where appropriate.
* src/parse-simulation.h, src/parse-simulation.c
* src/state-item.h (state_item_list_next): New.
Use it where appropriate.
* src/parse_simulation.c: Fix bug in parse_state_free.
Free new_root when simulate_reduction generates zero states.
* src/parse-simulation.c, src/parse-simulation.h
(parse_state_list, parse_state_list_append): New.
* src/parse-simulation.c, src/parse-simulation.h,
* src/counterexample.c: Replace all uses of lists of parse states and
appends to parse_state_lists with the new API.
* src/derivation.h, src/derivation.c: Make derivation struct opaque.
Add derivation_list type for clarity.
(derivation_list_new): New.
(derivation_list_append): New.
(derivation_list_prepend): New.
(derivation_new_leaf): New constructor for derivations with no
children.
* src/counterexample.c, src/parse-simulation.c,
* src/parse-simulation.h: Replace uses of gl_list_t containing
derivations with derivation_list and its API.
Replace calls of dervation_new using null children with
derivation_new_leaf.
* src/parse-simulation.c: replace ps_chunk and its API with typed
versions si_chunk and deriv_chunk.
* src/parse-simlation.h, src/parse-simulation.c: Remove
parse_state_retain_deriv in favor of derivation reference counting.
* src/counterexample.c: Remove search_state_retain_deriv.
* src/parse-simulation.c: Replace reference counting with
parse_state_retain everywhere.
(free_parse_state): Make this function iterative instead of
recursive. Long parse_state chains were causing stack exhaustion.
* tests/counterexample.at: Fix expectations.
