Simplify the if-else test in longest_match_lstat_cache() such that we
only have one simple if test. Instead of testing for 'i == cache.len'
or 'i == len', we transform this to a common test for 'i == max_len'.
And to further optimise we use 'i >= max_len' instead of 'i ==
max_len', the reason is that it is now the exact opposite of one part
inside the while-loop termination expression 'i < max_len && name[i]
== cache.path[i]', and then the compiler can hopefully/probably reuse
a test-result from it.
We do similar transformations inside the lstat_cache() and the
invalidate_lstat_cache() functions.
The result is a little smaller text-size as shown below:
~/git/git $ size symlinks_??_*
text data bss dec hex filename
1282 0 4116 5398 1516 symlinks_O2_after.o
1378 0 4116 5494 1576 symlinks_O2_before.o
896 0 4116 5012 1394 symlinks_Os_after.o
902 0 4116 5018 139a symlinks_Os_before.o
'O2' means that the file is compiled with 'gcc -O2', and similar 'Os'
means that the file is compiled with 'gcc -Os' (gcc 4.3.2).
Signed-off-by: Kjetil Barvik <barvik@xxxxxxxxxxxx>
---
symlinks.c | 25 +++++++++++++------------
1 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/symlinks.c b/symlinks.c
index f262b7c..81f490c 100644
--- a/symlinks.c
+++ b/symlinks.c
@@ -25,15 +25,16 @@ static inline int longest_match_lstat_cache(int len, const char *name,
}
i++;
}
- /* Is the cached path string a substring of 'name'? */
- if (i == cache.len && cache.len < len && name[cache.len] == '/') {
- match_len_prev = match_len;
- match_len = cache.len;
- /* Is 'name' a substring of the cached path string? */
- } else if ((i == len && len < cache.len && cache.path[len] == '/') ||
- (i == len && len == cache.len)) {
+ /*
+ * Is the cached path string a substring of 'name', is 'name'
+ * a substring of the cached path string, or is 'name' and the
+ * cached path string the exact same string?
+ */
+ if (i >= max_len && ((i < len && name[i] == '/') ||
+ (i < cache.len && cache.path[i] == '/') ||
+ (len == cache.len))) {
match_len_prev = match_len;
- match_len = len;
+ match_len = i;
}
*previous_slash = match_len_prev;
return match_len;
@@ -91,7 +92,7 @@ static int lstat_cache(int len, const char *name,
match_len = last_slash =
longest_match_lstat_cache(len, name, &previous_slash);
match_flags = cache.flags & track_flags & (FL_NOENT|FL_SYMLINK);
- if (match_flags && match_len == cache.len)
+ if (match_flags && match_len >= cache.len)
return match_flags;
/*
* If we now have match_len > 0, we would know that
@@ -102,7 +103,7 @@ static int lstat_cache(int len, const char *name,
* we can return immediately.
*/
match_flags = track_flags & FL_DIR;
- if (match_flags && len == match_len)
+ if (match_flags && match_len >= len)
return match_flags;
}
@@ -153,7 +154,7 @@ static int lstat_cache(int len, const char *name,
cache.path[last_slash] = '\0';
cache.len = last_slash;
cache.flags = save_flags;
- } else if (track_flags & FL_DIR &&
+ } else if ((track_flags & FL_DIR) &&
last_slash_dir > 0 && last_slash_dir <= PATH_MAX) {
/*
* We have a separate test for the directory case,
@@ -184,7 +185,7 @@ void invalidate_lstat_cache(int len, const char *name)
int match_len, previous_slash;
match_len = longest_match_lstat_cache(len, name, &previous_slash);
- if (len == match_len) {
+ if (match_len >= len) {
if ((cache.track_flags & FL_DIR) && previous_slash > 0) {
cache.path[previous_slash] = '\0';
cache.len = previous_slash;
--
1.6.1.349.g99fa5
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