Add precomputed arridx to duk_hstring

svaarala · svaarala · commit fe3f95bb3369 · 2016-11-05T01:13:44.000+02:00
diff --git a/src-input/duk_bi_string.c b/src-input/duk_bi_string.c
@@ -1295,7 +1295,7 @@ DUK_INTERNAL duk_ret_t duk_bi_string_prototype_repeat(duk_context *ctx) {
 	duk_uint8_t *p;
 	duk_double_t d;
 #if !defined(DUK_USE_PREFER_SIZE)
-	duk_uint_t copy_size;
+	duk_size_t copy_size;
 	duk_uint8_t *p_end;
 #endif
 
diff --git a/src-input/duk_heap_stringtable.c b/src-input/duk_heap_stringtable.c
@@ -37,7 +37,9 @@ duk_hstring *duk__alloc_init_hstring(duk_heap *heap,
 	duk_hstring *res = NULL;
 	duk_uint8_t *data;
 	duk_size_t alloc_size;
+#if !defined(DUK_USE_HSTRING_ARRIDX)
 	duk_uarridx_t dummy;
+#endif
 	duk_uint32_t clen;
 
 #if defined(DUK_USE_STRLEN16)
@@ -80,7 +82,11 @@ duk_hstring *duk__alloc_init_hstring(duk_heap *heap,
 	}
 
 	DUK_ASSERT(!DUK_HSTRING_HAS_ARRIDX(res));
+#if defined(DUK_USE_HSTRING_ARRIDX)
+	if (duk_js_to_arrayindex_raw_string(str, blen, &res->arridx)) {
+#else
 	if (duk_js_to_arrayindex_raw_string(str, blen, &dummy)) {
+#endif
 		DUK_HSTRING_SET_ARRIDX(res);
 	}
 
diff --git a/src-input/duk_hstring.h b/src-input/duk_hstring.h
@@ -134,15 +134,20 @@
 /* marker value; in E5 2^32-1 is not a valid array index (2^32-2 is highest valid) */
 #define DUK_HSTRING_NO_ARRAY_INDEX  (0xffffffffUL)
 
-/* get array index related to string (or return DUK_HSTRING_NO_ARRAY_INDEX);
+#if defined(DUK_USE_HSTRING_ARRIDX)
+#define DUK_HSTRING_GET_ARRIDX_FAST(h)  ((h)->arridx)
+#define DUK_HSTRING_GET_ARRIDX_SLOW(h)  ((h)->arridx)
+#else
+/* Get array index related to string (or return DUK_HSTRING_NO_ARRAY_INDEX);
  * avoids helper call if string has no array index value.
  */
 #define DUK_HSTRING_GET_ARRIDX_FAST(h)  \
 	(DUK_HSTRING_HAS_ARRIDX((h)) ? duk_js_to_arrayindex_string_helper((h)) : DUK_HSTRING_NO_ARRAY_INDEX)
 
-/* slower but more compact variant */
+/* Slower but more compact variant. */
 #define DUK_HSTRING_GET_ARRIDX_SLOW(h)  \
 	(duk_js_to_arrayindex_string_helper((h)))
+#endif
 
 /*
  *  Misc
@@ -167,6 +172,11 @@ struct duk_hstring {
 	duk_uint32_t hash;
 #endif
 
+	/* precomputed array index (or DUK_HSTRING_NO_ARRAY_INDEX) */
+#if defined(DUK_USE_HSTRING_ARRIDX)
+	duk_uarridx_t arridx;
+#endif
+
 	/* length in bytes (not counting NUL term) */
 #if defined(DUK_USE_STRLEN16)
 	/* placed in duk_heaphdr_string */
diff --git a/src-input/duk_js_ops.c b/src-input/duk_js_ops.c
@@ -1277,8 +1277,10 @@ DUK_INTERNAL duk_small_uint_t duk_js_typeof_stridx(duk_tval *tv_x) {
  *  Array index: E5 Section 15.4
  *  Array length: E5 Section 15.4.5.1 steps 3.c - 3.d (array length write)
  *
- *  The DUK_HSTRING_GET_ARRIDX_SLOW() and DUK_HSTRING_GET_ARRIDX_FAST() macros
- *  call duk_js_to_arrayindex_string_helper().
+ *  duk_js_to_arrayindex_string_helper() computes the array index from
+ *  string contents alone.  Depending on options it's only called during
+ *  string intern (and value stored to duk_hstring) or it's called also
+ *  at runtime.
  */
 
 DUK_INTERNAL duk_small_int_t duk_js_to_arrayindex_raw_string(const duk_uint8_t *str, duk_uint32_t blen, duk_uarridx_t *out_idx) {
