Changeset 197416 in webkit for trunk/Source/JavaScriptCore/runtime

Timestamp:

Mar 1, 2016, 3:35:05 PM (9 years ago)

Author:

[email protected]

Message:

FTL should simplify StringReplace with an empty replacement string
​https://bugs.webkit.org/show_bug.cgi?id=154871

Reviewed by Michael Saboff.

This is a simple and hugely profitable change. If we do a string.replace(/things/, ""), then
this calls directly into StringPrototype's replace-with-empty-string logic instead of going
through stuff that does checks before reaching that same conclusion.

This speeds up Octane/regexp by about 6-10%. It also speeds up the attached microbenchmark by
about 7%.

• ftl/FTLLowerDFGToB3.cpp:

(JSC::FTL::DFG::LowerDFGToB3::compileStringReplace):

• runtime/StringPrototype.cpp:

(JSC::jsSpliceSubstringsWithSeparators):
(JSC::removeUsingRegExpSearch):
(JSC::replaceUsingRegExpSearch):
(JSC::operationStringProtoFuncReplaceRegExpEmptyStr):
(JSC::operationStringProtoFuncReplaceRegExpString):

• runtime/StringPrototype.h:

Location:

trunk/Source/JavaScriptCore/runtime

Files:

• StringPrototype.cpp (modified) (3 diffs)
• StringPrototype.h (modified) (1 diff)

trunk/Source/JavaScriptCore/runtime/StringPrototype.cpp

@@ -447 +447 @@
 }
 
-static NEVER_INLINE EncodedJSValue removeUsingRegExpSearch(ExecState* exec, JSString* string, const String& source, RegExp* regExp)
+static ALWAYS_INLINE EncodedJSValue removeUsingRegExpSearch(ExecState* exec, JSString* string, const String& source, RegExp* regExp)
 {
     size_t lastIndex = 0;
@@ -507 +507 @@
     }
 
+    // FIXME: This is wrong because we may be called directly from the FTL.
+    // https://bugs.webkit.org/show_bug.cgi?id=154874
     RegExpConstructor* regExpConstructor = exec->lexicalGlobalObject()->regExpConstructor();
 
@@ -663 +665 @@
 
     return JSValue::encode(jsSpliceSubstringsWithSeparators(exec, string, source, sourceRanges.data(), sourceRanges.size(), replacements.data(), replacements.size()));
+}
+
+EncodedJSValue JIT_OPERATION operationStringProtoFuncReplaceRegExpEmptyStr(
+    ExecState* exec, JSString* thisValue, RegExpObject* searchValue)
+{
+    RegExp* regExp = searchValue->regExp();
+    if (regExp->global()) {
+        // ES5.1 15.5.4.10 step 8.a.
+        searchValue->setLastIndex(exec, 0);
+        if (exec->hadException())
+            return JSValue::encode(jsUndefined());
+        return removeUsingRegExpSearch(exec, thisValue, thisValue->value(exec), regExp);
+    }
+
+    CallData callData;
+    String replacementString = emptyString();
+    return replaceUsingRegExpSearch(
+        exec, thisValue, searchValue, callData, CallTypeNone, replacementString, JSValue());
 }
 

trunk/Source/JavaScriptCore/runtime/StringPrototype.h

@@ -55 +55 @@
 
 EncodedJSValue JIT_OPERATION operationStringProtoFuncReplaceGeneric(
-    ExecState* exec, EncodedJSValue thisValue, EncodedJSValue searchValue,
-    EncodedJSValue replaceValue);
+    ExecState*, EncodedJSValue thisValue, EncodedJSValue searchValue, EncodedJSValue replaceValue);
+
+EncodedJSValue JIT_OPERATION operationStringProtoFuncReplaceRegExpEmptyStr(
+    ExecState*, JSString* thisValue, RegExpObject* searchValue);
 
 EncodedJSValue JIT_OPERATION operationStringProtoFuncReplaceRegExpString(
-    ExecState* exec, JSString* thisValue, RegExpObject* searchValue, JSString* replaceValue);
+    ExecState*, JSString* thisValue, RegExpObject* searchValue, JSString* replaceValue);
 
 } // namespace JSC