Changeset: 365056899ff8 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=365056899ff8
Modified Files:
gdk/gdk_string.c
Branch: default
Log Message:
Annotate checkUTF8 for better branch prediction.
diffs (94 lines):
diff --git a/gdk/gdk_string.c b/gdk/gdk_string.c
--- a/gdk/gdk_string.c
+++ b/gdk/gdk_string.c
@@ -179,41 +179,54 @@ strLocate(Heap *h, const char *v)
static inline gdk_return
checkUTF8(const char *v)
{
+ /* It is unlikely that this functions returns GDK_FAIL, because
+ * it is likely that the string presented is a correctly coded
+ * UTF-8 string. So we annotate the tests that are very
+ * unlikely to succeed, i.e. the ones that lead to a return of
+ * GDK_FAIL, as being expected to return 0 using the
+ * __builtin_expect function. */
+#ifndef __GNUC__
+ /* __builtin_expect returns its first argument; it is expected
+ * to be equal to the second argument */
+#define __builtin_expect(expr, expect) (expr)
+#endif
if (v[0] != '\200' || v[1] != '\0') {
- /* check that string is correctly encoded UTF-8; there
- * was no need to do this earlier: if the string was
- * found above, it must have gone through here in the
- * past */
- int nutf8 = 0;
- int m = 0;
+ /* check that string is correctly encoded UTF-8 */
for (size_t i = 0; v[i]; i++) {
- if (nutf8 > 0) {
- if ((v[i] & 0xC0) != 0x80 ||
- (m != 0 && (v[i] & m) == 0))
- goto badutf8;
- m = 0;
- nutf8--;
+ /* we do not annotate all tests, only the ones
+ * leading directly to an unlikely return
+ * statement */
+ if ((v[i] & 0x80) == 0) {
+ ;
} else if ((v[i] & 0xE0) == 0xC0) {
- nutf8 = 1;
- if ((v[i] & 0x1E) == 0)
- goto badutf8;
+ if (__builtin_expect((v[i] & 0x1E) == 0, 0))
+ return GDK_FAIL;
+ if (__builtin_expect((v[++i] & 0xC0) != 0x80,
0))
+ return GDK_FAIL;
} else if ((v[i] & 0xF0) == 0xE0) {
- nutf8 = 2;
- if ((v[i] & 0x0F) == 0)
- m = 0x20;
+ if (__builtin_expect((v[++i] & 0xC0) != 0x80,
0))
+ return GDK_FAIL;
+ if ((v[i] & 0x0F) == 0) {
+ if (__builtin_expect((v[++i] & 0xE0) !=
0xA0, 0))
+ return GDK_FAIL;
+ } else if (__builtin_expect((v[++i] & 0xC0) !=
0x80, 0))
+ return GDK_FAIL;
} else if ((v[i] & 0xF8) == 0xF0) {
- nutf8 = 3;
- if ((v[i] & 0x07) == 0)
- m = 0x30;
- } else if ((v[i] & 0x80) != 0) {
- goto badutf8;
+ if (__builtin_expect((v[i+1] & 0x07) == 0 &&
+ (v[i+2] & 0x30) == 0, 0))
+ return GDK_FAIL;
+ if (__builtin_expect((v[++i] & 0xC0) != 0x80,
0))
+ return GDK_FAIL;
+ if (__builtin_expect((v[++i] & 0xC0) != 0x80,
0))
+ return GDK_FAIL;
+ if (__builtin_expect((v[++i] & 0xC0) != 0x80,
0))
+ return GDK_FAIL;
+ } else {
+ return GDK_FAIL;
}
}
}
return GDK_SUCCEED;
-
- badutf8:
- return GDK_FAIL;
}
var_t
@@ -261,6 +274,9 @@ strPut(BAT *b, var_t *dst, const void *V
}
/* the string was not found in the heap, we need to enter it */
+ /* check that string is correctly encoded UTF-8; there was no
+ * need to do this earlier: if the string was found above, it
+ * must have gone through here in the past */
if (checkUTF8(v) != GDK_SUCCEED) {
GDKerror("incorrectly encoded UTF-8\n");
return 0;
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