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Re: Questionable code in gcov-io.c
On 10/12/16 11:04, Andreas Schwab wrote:
Do we still need to call fstat? I don't think it can ever fail here.
Update removing the fstat. Survived a profiled bootstrap, so I'll commit
tomorrow, unless there are further comments. Thanks for spotting this!
nathan
2016-10-12 Nathan Sidwell <nathan@acm.org>
* gcov-io.c (gcov_open): Fix documentation. Simplify setting
gcov_var.mode. Remove unnecessary fstat.
Index: gcov-io.c
===================================================================
--- gcov-io.c (revision 241027)
+++ gcov-io.c (working copy)
@@ -115,10 +115,9 @@ static inline gcov_unsigned_t from_file
opened. If MODE is >= 0 an existing file will be opened, if
possible, and if MODE is <= 0, a new file will be created. Use
MODE=0 to attempt to reopen an existing file and then fall back on
- creating a new one. If MODE < 0, the file will be opened in
+ creating a new one. If MODE > 0, the file will be opened in
read-only mode. Otherwise it will be opened for modification.
- Return zero on failure, >0 on opening an existing file and <0 on
- creating a new one. */
+ Return zero on failure, non-zero on success. */
GCOV_LINKAGE int
#if IN_LIBGCOV
@@ -156,17 +155,12 @@ gcov_open (const char *name, int mode)
/* pass mode (ignored) for compatibility */
fd = open (name, O_RDONLY, S_IRUSR | S_IWUSR);
}
- else if (mode < 0)
+ else
{
/* Write mode - acquire a write-lock. */
s_flock.l_type = F_WRLCK;
- fd = open (name, O_RDWR | O_CREAT | O_TRUNC, 0666);
- }
- else /* mode == 0 */
- {
- /* Read-Write mode - acquire a write-lock. */
- s_flock.l_type = F_WRLCK;
- fd = open (name, O_RDWR | O_CREAT, 0666);
+ /* Truncate if force new mode. */
+ fd = open (name, O_RDWR | O_CREAT | (mode < 0 ? O_TRUNC : 0), 0666);
}
if (fd < 0)
return 0;
@@ -181,42 +175,23 @@ gcov_open (const char *name, int mode)
close (fd);
return 0;
}
-
- if (mode > 0)
- gcov_var.mode = 1;
- else if (mode == 0)
- {
- struct stat st;
-
- if (fstat (fd, &st) < 0)
- {
- fclose (gcov_var.file);
- gcov_var.file = 0;
- return 0;
- }
- if (st.st_size != 0)
- gcov_var.mode = 1;
- else
- gcov_var.mode = mode * 2 + 1;
- }
- else
- gcov_var.mode = mode * 2 + 1;
#else
if (mode >= 0)
+ /* Open an existing file. */
gcov_var.file = fopen (name, (mode > 0) ? "rb" : "r+b");
if (gcov_var.file)
- gcov_var.mode = 1;
+ mode = 1;
else if (mode <= 0)
- {
- gcov_var.file = fopen (name, "w+b");
- if (gcov_var.file)
- gcov_var.mode = mode * 2 + 1;
- }
+ /* Create a new file. */
+ gcov_var.file = fopen (name, "w+b");
+
if (!gcov_var.file)
return 0;
#endif
+ gcov_var.mode = mode ? mode : 1;
+
setbuf (gcov_var.file, (char *)0);
return 1;