uftrace: Fix dead store warnings found by infer

[paranlee]

uftrace: Fix dead store warnings found by infer

This patch fixes some dead store warnings found by a static analysis
tool, called infer[1].

The warning messages are as follows.

  $ cd /path/to/uftrace
  $ infer run --force-integration make
          ...
  utils/debug.c:386: error: Dead Store
    The value written to `&percent` (type `double`) is never used.
    384. void print_diff_percent(uint64_t base_nsec, uint64_t pair_nsec)
    385. {
    386. 	double percent = 999.99;
          ^

  utils/debug.c:387: error: Dead Store
    The value written to `&sc` is never used.
    385. {
    386.  double percent = 999.99;
    387.  const char *sc = get_color(COLOR_CODE_NORMAL);
          ^
    388.  const char *ec = get_color(COLOR_CODE_RESET);
    389.

  utils/kernel.c:57: error: Dead Store
    The value written to `&ret` is never used.
    55. {
    56.   struct kfilter *pos, *tmp;
    57.   int ret = -1;
         ^
    58.   int fd;
    59.

  utils/perf.c:230: error: Dead Store
    The value written to `&start` is never used.
    228.  buf = &data[start & mask];
    229.  size = end - start;
    230.  start += size;
          ^

[1] https://github.com/facebook/infer

Fixed: #1553
Signed-off-by: Paran Lee p4ranlee@gmail.com

[namhyung]

LGTM

[honggyukim]

Please squash the change at #1758 into this PR.

[honggyukim]

Please rewrite the commit message by looking at the other commit messages especially as follows.

1. use Fixed: #1553
2. write the commit message in complete sentences

[honggyukim]

The commit message doesn't follow our style again.

The description Remove Not needed initialization on double variable. is not a complete sentence and upper case shouldn't be appeared in the middle of sentence.

Fixed: #1553 is better to be placed after a single blank line. Please read other commit message by running git log and see what is different in your commit message from others.

[honggyukim]

In addition, the current commit message only explains about the first change.

diff --git a/utils/debug.c b/utils/debug.c
index bbf526fe2..3d779570d 100644
--- a/utils/debug.c
+++ b/utils/debug.c
@@ -383,7 +383,7 @@ void print_time_unit(uint64_t delta_nsec)
 
 void print_diff_percent(uint64_t base_nsec, uint64_t pair_nsec)
 {
-	double percent = 999.99;
+	double percent;
 	const char *sc = get_color(COLOR_CODE_NORMAL);
 	const char *ec = get_color(COLOR_CODE_RESET);

There is no explanation about the second change below.

diff --git a/utils/kernel.c b/utils/kernel.c
index 3a33b67e1..2d2d277b3 100644
--- a/utils/kernel.c
+++ b/utils/kernel.c
@@ -54,7 +54,6 @@ struct kfilter {
 static int set_filter_file(const char *filter_file, struct list_head *filters)
 {
 	struct kfilter *pos, *tmp;
-	int ret = -1;
 	int fd;
 
 	fd = open_tracing_file(filter_file, true);
@@ -75,10 +74,9 @@ static int set_filter_file(const char *filter_file, struct list_head *filters)
 		if (write(fd, " ", 1) != 1)
 			pr_dbg2("writing filter file failed, but ignoring...\n");
 	}
-	ret = 0;
 
 	close(fd);
-	return ret;
+	return 0;
 }
 
 static int set_tracing_filter(struct uftrace_kernel_writer *kernel)

I would rather write the description as follows.

Subject: [PATCH] uftrace: Fix dead store warnings found by infer

This patch fixes some dead store warnings found by a static analysis
tool, called infer[1].

The warning messages are as follows.

  $ cd /path/to/uftrace
  $ infer run --force-integration make
          ...
  #24
  utils/debug.c:386: error: Dead Store
    The value written to `&percent` (type `double`) is never used.
    384. void print_diff_percent(uint64_t base_nsec, uint64_t pair_nsec)
    385. {
    386. 	double percent = 999.99;
          ^

  #28
  utils/kernel.c:57: error: Dead Store
    The value written to `&ret` (type `int`) is never used.
    55. {
    56. 	struct kfilter *pos, *tmp;
    57. 	int ret = -1;
         ^
    58. 	int fd;
    59. 

[1] https://github.com/facebook/infer

Fixed: #1553
Signed-off-by: Paran Lee <p4ranlee@gmail.com>

Please write the commit message with meaningful information.

[namhyung]

Can you please remove something like #24 in the commit message. They make references to unrelated issues.

[paranlee]

@namhyung Thank you for the code review! I amended a new patch. :)

[honggyukim]

The current commit message title is too long and it's better not to exceed more than 50 or 72 characters.
https://www.gitkraken.com/learn/git/best-practices/git-commit-message#git-commit-message-structure

[honggyukim]

The current commit message title is too long and it's better not to exceed more than 50 or 72 characters.
https://www.gitkraken.com/learn/git/best-practices/git-commit-message#git-commit-message-structure

The commit title is still too long so make it short.

uftrace: Fix dead store warnings found by infer and warning on compile time implicit declaration

[honggyukim]

LGTM!