Revision: 13337
Author: [email protected]
Date: Wed Jan 9 01:32:12 2013
Log: Added %FlattenString and use it to speed up a regression test.
Flattening strings is relatively costly and by doing it after every
duplication
we avoid combinatorial explosion.
Note that flattening could have been done by e.g. using a regular
expression,
too, but this is just another implementation detail and %FlattenString seems
general enough to be useful in other tests, too.
Review URL: https://codereview.chromium.org/11828014
http://code.google.com/p/v8/source/detail?r=13337
Modified:
/branches/bleeding_edge/src/runtime.cc
/branches/bleeding_edge/src/runtime.h
/branches/bleeding_edge/test/mjsunit/regress/regress-crbug-160010.js
=======================================
--- /branches/bleeding_edge/src/runtime.cc Mon Jan 7 02:06:11 2013
+++ /branches/bleeding_edge/src/runtime.cc Wed Jan 9 01:32:12 2013
@@ -13240,6 +13240,15 @@
UNREACHABLE();
return NULL;
}
+
+
+RUNTIME_FUNCTION(MaybeObject*, Runtime_FlattenString) {
+ HandleScope scope(isolate);
+ ASSERT(args.length() == 1);
+ CONVERT_ARG_HANDLE_CHECKED(String, str, 0);
+ FlattenString(str);
+ return isolate->heap()->undefined_value();
+}
RUNTIME_FUNCTION(MaybeObject*, Runtime_GetFromCache) {
=======================================
--- /branches/bleeding_edge/src/runtime.h Mon Jan 7 02:06:11 2013
+++ /branches/bleeding_edge/src/runtime.h Wed Jan 9 01:32:12 2013
@@ -104,6 +104,7 @@
F(StoreArrayLiteralElement, 5, 1) \
F(DebugCallbackSupportsStepping, 1, 1) \
F(DebugPrepareStepInIfStepping, 1, 1) \
+ F(FlattenString, 1, 1) \
\
/* Array join support */ \
F(PushIfAbsent, 2, 1) \
=======================================
--- /branches/bleeding_edge/test/mjsunit/regress/regress-crbug-160010.js
Mon Nov 12 02:20:07 2012
+++ /branches/bleeding_edge/test/mjsunit/regress/regress-crbug-160010.js
Wed Jan 9 01:32:12 2013
@@ -25,9 +25,11 @@
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+// Flags: --allow-natives-syntax
+
var str = "a";
for (var i = 0; i < 28; i++) {
str += str;
+ %FlattenString(str); // Evil performance hack
}
JSON.stringify(str);
-
--
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