[PATCH v3 4/4] cocci: generalize "unused" rule to cover more than "strbuf"
- From
Ævar Arnfjörð Bjarmason <avarab@gmail.com>
- Date
- Jul 1, 2022, 10:30 UTC
- Message-ID
- <patch-v3-4.4-45a429b9cc9-20220701T102506Z-avarab@gmail.com>
- In-Reply-To
- <cover-v3-0.4-00000000000-20220701T102506Z-avarab@gmail.com>
Generalize the newly added "unused.cocci" rule to find more than just "struct strbuf", let's have it find the same unused patterns for "struct string_list", as well as other code that uses similar-looking *_{release,clear,free}() and {release,clear,free}_*() functions.
See [1] for example of code that would be covered by the "get_worktrees()" part of this rule. We'd still need work that the series is based on (we were passing "worktrees" to a function), but could now do the change in [1] automatically.
1. https://lore.kernel.org/git/Yq6eJFUPPTv%2Fzc0o@coredump.intra.peff.net/
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> --- builtin/repack.c | 2 -- contrib/coccinelle/unused.cocci | 31 ++++++++++++++++++++++++------- 2 files changed, 24 insertions(+), 9 deletions(-)
diff --git a/builtin/repack.c b/builtin/repack.c index 4a7ae4cf489..482b66f57d6 100644 --- a/builtin/repack.c +++ b/builtin/repack.c @@ -727,7 +727,6 @@ int cmd_repack(int argc, const char **argv, const char *prefix) struct child_process cmd = CHILD_PROCESS_INIT; struct string_list_item *item; struct string_list names = STRING_LIST_INIT_DUP; - struct string_list rollback = STRING_LIST_INIT_NODUP; struct string_list existing_nonkept_packs = STRING_LIST_INIT_DUP; struct string_list existing_kept_packs = STRING_LIST_INIT_DUP; struct pack_geometry *geometry = NULL; @@ -1117,7 +1116,6 @@ int cmd_repack(int argc, const char **argv, const char *prefix) } string_list_clear(&names, 0); - string_list_clear(&rollback, 0); string_list_clear(&existing_nonkept_packs, 0); string_list_clear(&existing_kept_packs, 0); clear_pack_geometry(geometry); diff --git a/contrib/coccinelle/unused.cocci b/contrib/coccinelle/unused.cocci index 9f0101c1350..a1b09d2d73d 100644 --- a/contrib/coccinelle/unused.cocci +++ b/contrib/coccinelle/unused.cocci @@ -1,5 +1,5 @@ // This rule finds sequences of "unused" declerations and uses of -// "struct strbuf". +// "struct strbuf" and other common types. // // I.e. this finds cases where we only declare the variable, and then // release it, e.g.: @@ -20,14 +20,18 @@ @@ type T; identifier I; -// STRBUF_INIT -constant INIT_MACRO =~ "^STRBUF_INIT$"; +// STRBUF_INIT, but also e.g. STRING_LIST_INIT_DUP (so no anchoring) +constant INIT_MACRO =~ "_INIT"; // x[mc]alloc() etc. identifier MALLOC1 =~ "^x?[mc]alloc$"; +// I = get_worktrees() etc. +identifier INIT_ASSIGN1 =~ "^get_worktrees$"; // strbuf_init(&I, ...) etc. -identifier INIT_CALL1 =~ "^strbuf_init$"; -// strbuf_release() -identifier REL1 =~ "^strbuf_release$"; +identifier INIT_CALL1 =~ "^[a-z_]*_init$"; +// stbuf_release(), string_list_clear() etc. +identifier REL1 =~ "^[a-z_]*_(release|clear|free)$"; +// release_patch(), clear_pathspec() etc. +identifier REL2 =~ "^(release|clear|free)_[a-z_]*$"; @@ // .. A declaration like "struct strbuf buf;"... @@ -52,6 +56,10 @@ identifier REL1 =~ "^strbuf_release$"; // "strbuf_init(&buf, ...)" ... - \( INIT_CALL1 \)( \( I \| &I \), ...); | +// .. or e.g. "worktrees = get_worktrees();", i.e. a known "assignment +// init" ... +- I = \( INIT_ASSIGN1 \)(...); +| // .. or to follow-up a "struct strbuf *buf" with e.g. "buf = // xmalloc(...)" (which may in turn be followed-up by a // "strbuf_init()", which we'll match with INIT_CALL1) ... @@ -61,11 +69,20 @@ identifier REL1 =~ "^strbuf_release$"; // ... and then no mention of "buf" or "&buf" until we get to a // strbuf_release(&buf) at the end ... -- \( REL1 \)( \( &I \| I \) ); +( +- \( REL1 \| REL2 \)( \( I \| &I \), ...); +| +- \( REL1 \| REL2 \)( \( &I \| I \) ); +) // ... and no use *after* either, e.g. we don't want to delete // init/strbuf_release() patterns, where "&buf" could be used // afterwards. ... when != \( I \| &I \) +// Note that we're intentionally loose in accepting e.g. a +// "strbuf_init(&buf)" followed by a "string_list_clear(&buf, +// 0)". It's assumed that the compiler will catch any such invalid +// code, i.e. that our constructors/destructors don't take a "void *". +// // This rule also isn't capable of finding cases where &buf is used, // but only to e.g. pass that variable to a static function which // doesn't use it. The analysis is only function-local.
-- 2.37.0.900.g4d0de1cceb2