Building the Linux kernel with Clang and LLVM
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From: Ian Rogers <irogers@google.com>
To: "Peter Zijlstra" <peterz@infradead.org>,
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Cc: Ian Rogers <irogers@google.com>
Subject: [PATCH v2 24/47] perf help: Silence -Wshorten-64-to-32 warnings
Date: Wed, 30 Apr 2025 10:50:12 -0700	[thread overview]
Message-ID: <20250430175036.184610-25-irogers@google.com> (raw)
In-Reply-To: <20250430175036.184610-1-irogers@google.com>

The clang warning -Wshorten-64-to-32 can be useful to catch
inadvertent truncation. In some instances this truncation can lead to
changing the sign of a result, for example, truncation to return an
int to fit a sort routine. Silence the warning by making the implicit
truncation explicit.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/builtin-help.c          |  4 ++--
 tools/perf/util/help-unknown-cmd.c | 14 ++++++++------
 tools/perf/util/levenshtein.c      | 18 +++++++++---------
 3 files changed, 19 insertions(+), 17 deletions(-)

diff --git a/tools/perf/builtin-help.c b/tools/perf/builtin-help.c
index 7be6fb6df595..05151c68191f 100644
--- a/tools/perf/builtin-help.c
+++ b/tools/perf/builtin-help.c
@@ -301,7 +301,7 @@ static struct cmdnames main_cmds, other_cmds;
 
 void list_common_cmds_help(void)
 {
-	unsigned int i, longest = 0;
+	size_t i, longest = 0;
 
 	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
 		if (longest < strlen(common_cmds[i].name))
@@ -310,7 +310,7 @@ void list_common_cmds_help(void)
 
 	puts(" The most commonly used perf commands are:");
 	for (i = 0; i < ARRAY_SIZE(common_cmds); i++) {
-		printf("   %-*s   ", longest, common_cmds[i].name);
+		printf("   %-*s   ", (int)longest, common_cmds[i].name);
 		puts(common_cmds[i].help);
 	}
 }
diff --git a/tools/perf/util/help-unknown-cmd.c b/tools/perf/util/help-unknown-cmd.c
index a0a46e34f8d1..f0a0b8c13a92 100644
--- a/tools/perf/util/help-unknown-cmd.c
+++ b/tools/perf/util/help-unknown-cmd.c
@@ -24,14 +24,15 @@ static int levenshtein_compare(const void *p1, const void *p2)
 {
 	const struct cmdname *const *c1 = p1, *const *c2 = p2;
 	const char *s1 = (*c1)->name, *s2 = (*c2)->name;
-	int l1 = (*c1)->len;
-	int l2 = (*c2)->len;
-	return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
+	ssize_t l1 = (*c1)->len;
+	ssize_t l2 = (*c2)->len;
+
+	return l1 != l2 ? (int)(l1 - l2) : (int)strcmp(s1, s2);
 }
 
 static int add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 {
-	unsigned int i, nr = cmds->cnt + old->cnt;
+	size_t nr = cmds->cnt + old->cnt;
 	void *tmp;
 
 	if (nr > cmds->alloc) {
@@ -45,7 +46,7 @@ static int add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 			return -1;
 		cmds->names = tmp;
 	}
-	for (i = 0; i < old->cnt; i++)
+	for (size_t i = 0; i < old->cnt; i++)
 		cmds->names[cmds->cnt++] = old->names[i];
 	zfree(&old->names);
 	old->cnt = 0;
@@ -54,7 +55,8 @@ static int add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 
 const char *help_unknown_cmd(const char *cmd, struct cmdnames *main_cmds)
 {
-	unsigned int i, n = 0, best_similarity = 0;
+	unsigned int i, n = 0;
+	size_t best_similarity = 0;
 	struct cmdnames other_cmds;
 
 	memset(&other_cmds, 0, sizeof(other_cmds));
diff --git a/tools/perf/util/levenshtein.c b/tools/perf/util/levenshtein.c
index 6a6712635aa4..f6912b848c4a 100644
--- a/tools/perf/util/levenshtein.c
+++ b/tools/perf/util/levenshtein.c
@@ -44,19 +44,19 @@
 int levenshtein(const char *string1, const char *string2,
 		int w, int s, int a, int d)
 {
-	int len1 = strlen(string1), len2 = strlen(string2);
+	size_t len1 = strlen(string1), len2 = strlen(string2);
 	int *row0 = malloc(sizeof(int) * (len2 + 1));
 	int *row1 = malloc(sizeof(int) * (len2 + 1));
 	int *row2 = malloc(sizeof(int) * (len2 + 1));
-	int i, j;
+	int ret;
 
-	for (j = 0; j <= len2; j++)
-		row1[j] = j * a;
-	for (i = 0; i < len1; i++) {
+	for (size_t j = 0; j <= len2; j++)
+		row1[j] = (int)j * a;
+	for (size_t i = 0; i < len1; i++) {
 		int *dummy;
 
-		row2[0] = (i + 1) * d;
-		for (j = 0; j < len2; j++) {
+		row2[0] = ((int)i + 1) * d;
+		for (size_t j = 0; j < len2; j++) {
 			/* substitution */
 			row2[j + 1] = row1[j] + s * (string1[i] != string2[j]);
 			/* swap */
@@ -78,10 +78,10 @@ int levenshtein(const char *string1, const char *string2,
 		row2 = dummy;
 	}
 
-	i = row1[len2];
+	ret = row1[len2];
 	free(row0);
 	free(row1);
 	free(row2);
 
-	return i;
+	return ret;
 }
-- 
2.49.0.906.g1f30a19c02-goog


  parent reply	other threads:[~2025-04-30 17:51 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-30 17:49 [PATCH v2 00/47] Perf build support for -Wshorten-64-to-32 Ian Rogers
2025-04-30 17:49 ` [PATCH v2 01/47] perf build: Avoid building libbpf/bpftool with LIBBPF_DYNAMIC Ian Rogers
2025-04-30 17:49 ` [PATCH v2 02/47] perf tests: Silence -Wshorten-64-to-32 warnings Ian Rogers
2025-04-30 17:49 ` [PATCH v2 03/47] perf ui: " Ian Rogers
2025-04-30 17:49 ` [PATCH v2 04/47] perf bench: " Ian Rogers
2025-04-30 20:23   ` Dirk Gouders
2025-04-30 21:04     ` Ian Rogers
2025-04-30 22:18       ` Dirk Gouders
2025-04-30 22:22         ` Ian Rogers
2025-04-30 23:11           ` Dirk Gouders
2025-05-02 12:06             ` David Laight
2025-05-02 14:12               ` Dirk Gouders
2025-05-03 10:05                 ` David Laight
2025-05-03 12:22                   ` Dirk Gouders
2025-04-30 17:49 ` [PATCH v2 05/47] arm64: cputype: " Ian Rogers
2025-05-09 12:56   ` Mark Rutland
2025-04-30 17:49 ` [PATCH v2 06/47] x86/insn: " Ian Rogers
2025-04-30 17:49 ` [PATCH v2 07/47] tools lib: " Ian Rogers
2025-04-30 17:49 ` [PATCH v2 08/47] libperf: " Ian Rogers
2025-04-30 17:49 ` [PATCH v2 09/47] tools subcmd: " Ian Rogers
2025-04-30 17:49 ` [PATCH v2 10/47] perf arch x86: " Ian Rogers
2025-04-30 17:49 ` [PATCH v2 11/47] perf arm-spe: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 12/47] perf trace: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 13/47] perf trace-event: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 14/47] perf jvmti: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 15/47] perf pmu: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 16/47] perf annotate powerpc: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 17/47] perf s390: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 18/47] perf cs-etm: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 19/47] perf stat: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 20/47] perf dlfilter: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 21/47] perf demangle: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 22/47] perf annotate: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 23/47] perf report: " Ian Rogers
2025-04-30 17:50 ` Ian Rogers [this message]
2025-04-30 17:50 ` [PATCH v2 25/47] perf hisi-ptt: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 26/47] perf probe: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 27/47] perf kwork: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 28/47] perf buildid: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 29/47] perf lock: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 30/47] perf mem: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 31/47] perf script: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 32/47] perf evlist: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 33/47] perf bpf_counter: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 34/47] perf ftrace: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 35/47] perf record: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 36/47] perf inject: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 37/47] perf sched: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 38/47] perf timechart: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 39/47] perf list: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 40/47] perf kvm: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 41/47] perf diff: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 42/47] perf daemon: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 43/47] perf zlib: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 44/47] perf symbol: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 45/47] perf util: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 46/47] perf hashmap: " Ian Rogers
2025-04-30 17:50 ` [PATCH v2 47/47] perf: " Ian Rogers

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