Reviewers: Mads Ager,
Description:
Revert "More generic version of Array.concat builtin."
Please review this at http://codereview.chromium.org/1058003
Affected files:
M src/builtins.cc
M src/v8-counters.h
Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index
d545c345d1d88a064745ce5fb00bc4640a3ce29d..4166b7121d269c5d38091cccf1b753425f306b00
100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -728,34 +728,36 @@ BUILTIN(ArraySplice) {
BUILTIN(ArrayConcat) {
- if (!ArrayPrototypeHasNoElements()) {
+ Counters::array_concat_builtin_total.Increment();
+ if (args.length() != 2) {
+ // Fast case only for concating two arrays.
+ return CallJsBuiltin("ArrayConcat", args);
+ }
+ Counters::array_concat_builtin_two_args.Increment();
+
+ Object* receiver_obj = *args.receiver();
+ FixedArray* receiver_elms = NULL;
+ Object* arg_obj = args[1];
+ FixedArray* arg_elms = NULL;
+ if (!IsJSArrayWithFastElements(receiver_obj, &receiver_elms)
+ || !IsJSArrayWithFastElements(arg_obj, &arg_elms)
+ || !ArrayPrototypeHasNoElements()) {
return CallJsBuiltin("ArrayConcat", args);
}
- // Iterate through all the arguments performing checks
- // and calculating total length.
- int n_arguments = args.length();
- int result_len = 0;
- for (int i = 0; i < n_arguments; i++) {
- Object* arg = args[i];
- if (!arg->IsJSArray() || JSArray::cast(arg)->HasFastElements()) {
- return CallJsBuiltin("ArrayConcat", args);
- }
-
- int len = Smi::cast(JSArray::cast(arg)->length())->value();
+ JSArray* receiver_array = JSArray::cast(receiver_obj);
+ ASSERT(receiver_array->HasFastElements());
+ JSArray* arg_array = JSArray::cast(arg_obj);
+ ASSERT(arg_array->HasFastElements());
- // We shouldn't overflow when adding another len.
- const int kHalfOfMaxInt = 1 << (kBitsPerInt - 2);
- STATIC_ASSERT(FixedArray::kMaxLength < kHalfOfMaxInt);
- USE(kHalfOfMaxInt);
- result_len += len;
- ASSERT(result_len >= 0);
+ int receiver_len = Smi::cast(receiver_array->length())->value();
+ int arg_len = Smi::cast(arg_array->length())->value();
+ ASSERT(receiver_len <= (Smi::kMaxValue - arg_len));
- if (result_len > FixedArray::kMaxLength) {
- return CallJsBuiltin("ArrayConcat", args);
- }
+ int result_len = receiver_len + arg_len;
+ if (result_len > FixedArray::kMaxSize) {
+ return CallJsBuiltin("ArrayConcat", args);
}
-
if (result_len == 0) {
return AllocateEmptyJSArray();
}
@@ -771,15 +773,8 @@ BUILTIN(ArrayConcat) {
// Copy data.
AssertNoAllocation no_gc;
- int start_pos = 0;
- for (int i = 0; i < n_arguments; i++) {
- JSArray* array = JSArray::cast(args[i]);
- FixedArray* elms = FixedArray::cast(array->elements());
- int len = Smi::cast(array->length())->value();
- CopyElements(&no_gc, result_elms, start_pos, elms, 0, len);
- start_pos += len;
- }
- ASSERT(start_pos == result_len);
+ CopyElements(&no_gc, result_elms, 0, receiver_elms, 0, receiver_len);
+ CopyElements(&no_gc, result_elms, receiver_len, arg_elms, 0, arg_len);
// Set the length and elements.
result_array->set_length(Smi::FromInt(result_len));
Index: src/v8-counters.h
diff --git a/src/v8-counters.h b/src/v8-counters.h
index
b595cd4922c2739b6b537c68a33507891d97f955..c1400ae4047f1b091c32d549a03499581cc740eb
100644
--- a/src/v8-counters.h
+++ b/src/v8-counters.h
@@ -151,6 +151,8 @@ namespace internal {
SC(constructed_objects_stub, V8.ConstructedObjectsStub) \
SC(array_function_runtime, V8.ArrayFunctionRuntime) \
SC(array_function_native, V8.ArrayFunctionNative) \
+ SC(array_concat_builtin_total, V8.ArrayConcatTotal) \
+ SC(array_concat_builtin_two_args, V8.ArrayConcatTwoArgs) \
SC(for_in, V8.ForIn) \
SC(enum_cache_hits, V8.EnumCacheHits) \
SC(enum_cache_misses, V8.EnumCacheMisses) \
--
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