Add an ASSERT_FOR_FANALYZER() macro to quiet those -fanalyzer issues that haven't been diagnosed yet to either change the code involved, or to add an assert() or BUG() to it to placate GCC v12's -fanalyzer mode. As in the preceding commit we could also use -Wno-error=* here, which was the initial implementation in config.mak.dev, i.e. something like: ## -Wno-error=analyzer-null-dereference $(eval $(call fn_disable_analyzer, \ -Wno-error=analyzer-null-dereference, \ dir \ gpg-interface \ graph \ range-diff \ utf8 \ )) ## -Wno-error=analyzer-null-dereference: pre-gcc12 ifeq ($(filter gcc12,$(COMPILER_FEATURES)),) $(eval $(call fn_disable_analyzer, \ -Wno-error=analyzer-null-dereference, \ merge \ builtin/name-rev \ )) endif But any such approach will unfortunately quiet *all* in the relevant files, including any new ones. Instead we want to quiet specific issues involved with ASSERT_FOR_FANALYZER(). A drawback of this overall approach is that this only works under e.g. CFLAGS=-O0, but not CFLAGS=-O3. The compiler takes the liberty to re-arrange our code to get around these assert()s, and other new issues will also crop up. All of this is expected (-fanalyzer is subject to optimization passes, like most other options), but let's focus on -O0 for now. Commentary on specific cases: * builtin/name-rev.c: Since 45a14f578e1 (Revert "name-rev: release unused name strings", 2022-04-22) GCC v12's -fanalyzer has complained about this code, per René's analysis in [1] it's incorrect to do so. So let's add an ASSERT_FOR_FANALYZER() to placate it. * graph.c: In 0f0f389f120 (graph: tidy up display of left-skewed merges, 2019-10-15) a previous "assert" was removed, and another unconditional deference of the return value of first_interesting_parent() was added without checking it. Since it can return NULL let's add ASSERT_FOR_FANALYZER()'s here to note for -fanalyzer that we won't be dereferencing these in practice. 1. https://lore.kernel.org/git/dece627d-ccf8-2375-0c50-c59637e561d3@xxxxxx/ Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> --- builtin/name-rev.c | 1 + config.mak.dev | 4 ++++ dir.c | 1 + git-compat-util.h | 16 ++++++++++++++++ gpg-interface.c | 2 ++ graph.c | 2 ++ line-log.c | 2 ++ unpack-trees.c | 1 + utf8.c | 1 + 9 files changed, 30 insertions(+) diff --git a/builtin/name-rev.c b/builtin/name-rev.c index 02ea9d16330..419159961b9 100644 --- a/builtin/name-rev.c +++ b/builtin/name-rev.c @@ -223,6 +223,7 @@ static void name_rev(struct commit *start_commit, if (commit_is_before_cutoff(parent)) continue; + ASSERT_FOR_FANALYZER(name); if (parent_number > 1) { generation = 0; distance = name->distance + MERGE_TRAVERSAL_WEIGHT; diff --git a/config.mak.dev b/config.mak.dev index d6f5be92297..1d47fc04163 100644 --- a/config.mak.dev +++ b/config.mak.dev @@ -83,6 +83,10 @@ endif DEVELOPER_CFLAGS += -fanalyzer +ifeq ($(filter no-suppress-analyzer,$(DEVOPTS)),) +DEVELOPER_CFLAGS += -DSUPPRESS_FSANITIZER +endif + ## -fanalyzer exists exists as of gcc10, but versions older than gcc12 ## have a lot of false positives. ifeq ($(filter gcc12,$(COMPILER_FEATURES)),) diff --git a/dir.c b/dir.c index 3633c0852ee..c80b584b4a7 100644 --- a/dir.c +++ b/dir.c @@ -3781,6 +3781,7 @@ static void invalidate_one_directory(struct untracked_cache *uc, struct untracked_cache_dir *ucd) { uc->dir_invalidated++; + ASSERT_FOR_FANALYZER(ucd); ucd->valid = 0; ucd->untracked_nr = 0; } diff --git a/git-compat-util.h b/git-compat-util.h index 96293b6c43a..a553884c048 100644 --- a/git-compat-util.h +++ b/git-compat-util.h @@ -984,6 +984,21 @@ static inline unsigned long cast_size_t_to_ulong(size_t a) return (unsigned long)a; } +/** + * Transitory helper macro to quiet currently known GCC -fsanitizer + * issues. + * + * We lie to it and say that we're confident that the given "expr" to + * ASSERT_FOR_FANALYZER() cannot be NULL (or 0). Those + * grandfathered-in issues should be fixed, but at least we're + * stemming the tide. + */ +#ifdef SUPPRESS_FSANITIZER +#define ASSERT_FOR_FANALYZER(expr) assert((expr)) +#else +#define ASSERT_FOR_FANALYZER(expr) do {} while (0) +#endif + #ifdef HAVE_ALLOCA_H # include <alloca.h> # define xalloca(size) (alloca(size)) @@ -1037,6 +1052,7 @@ int xstrncmpz(const char *s, const char *t, size_t len); BUILD_ASSERT_OR_ZERO(sizeof(*(dst)) == sizeof(*(src)))) static inline void copy_array(void *dst, const void *src, size_t n, size_t size) { + ASSERT_FOR_FANALYZER(dst); if (n) memcpy(dst, src, st_mult(size, n)); } diff --git a/gpg-interface.c b/gpg-interface.c index 280f1fa1a58..9cba3b86e45 100644 --- a/gpg-interface.c +++ b/gpg-interface.c @@ -242,6 +242,7 @@ static void parse_gpg_output(struct signature_check *sigc) next = strchrnul(line, ' '); replace_cstring(&sigc->key, line, next); /* Do we have signer information? */ + ASSERT_FOR_FANALYZER(next); if (*next && (sigcheck_gpg_status[i].flags & GPG_STATUS_UID)) { line = next + 1; next = strchrnul(line, '\n'); @@ -283,6 +284,7 @@ static void parse_gpg_output(struct signature_check *sigc) */ limit = strchrnul(line, '\n'); for (j = 9; j > 0; j--) { + ASSERT_FOR_FANALYZER(next); if (!*next || limit <= next) break; line = next + 1; diff --git a/graph.c b/graph.c index 568b6e7cd41..39f7e95d4ab 100644 --- a/graph.c +++ b/graph.c @@ -1105,6 +1105,7 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct graph_l seen_this = 1; for (j = 0; j < graph->num_parents; j++) { + ASSERT_FOR_FANALYZER(parents); par_column = graph_find_new_column_by_commit(graph, parents->item); assert(par_column >= 0); @@ -1138,6 +1139,7 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct graph_l } } + ASSERT_FOR_FANALYZER(first_parent); if (col_commit == first_parent->item) parent_col = col; } diff --git a/line-log.c b/line-log.c index 51d93310a4d..1295f46deaf 100644 --- a/line-log.c +++ b/line-log.c @@ -154,6 +154,7 @@ static void range_set_union(struct range_set *out, while (i < a->nr || j < b->nr) { struct range *new_range; if (i < a->nr && j < b->nr) { + ASSERT_FOR_FANALYZER(rb); if (ra[i].start < rb[j].start) new_range = &ra[i++]; else if (ra[i].start > rb[j].start) @@ -166,6 +167,7 @@ static void range_set_union(struct range_set *out, new_range = &ra[i++]; else /* a exhausted */ new_range = &rb[j++]; + ASSERT_FOR_FANALYZER(new_range); if (new_range->start == new_range->end) ; /* empty range */ else if (!out->nr || out->ranges[out->nr-1].end < new_range->start) { diff --git a/unpack-trees.c b/unpack-trees.c index a1d0ff3a4d3..b6e10b05a00 100644 --- a/unpack-trees.c +++ b/unpack-trees.c @@ -2195,6 +2195,7 @@ static int verify_clean_subdirectory(const struct cache_entry *ce, char *pathbuf; int cnt = 0; + ASSERT_FOR_FANALYZER(ce); if (S_ISGITLINK(ce->ce_mode)) { struct object_id oid; int sub_head = resolve_gitlink_ref(ce->name, "HEAD", &oid); diff --git a/utf8.c b/utf8.c index de4ce5c0e68..3ffc0a97f3b 100644 --- a/utf8.c +++ b/utf8.c @@ -130,6 +130,7 @@ static ucs_char_t pick_one_utf8_char(const char **start, size_t *remainder_p) */ remainder = (remainder_p ? *remainder_p : 999); + ASSERT_FOR_FANALYZER(remainder < 1 || s); if (remainder < 1) { goto invalid; } else if (*s < 0x80) { -- 2.36.1.1124.g577fa9c2ebd
