Changeset 88719 in webkit for trunk/Source/JavaScriptCore/parser/Lexer.h

Timestamp:

Jun 13, 2011, 3:38:22 PM (14 years ago)

Author:

[email protected]

Message:

2011-06-13 Oliver Hunt <​[email protected]>

Reviewed by Gavin Barraclough.

Make it possible to inline the common case of identifier lexing
​https://bugs.webkit.org/show_bug.cgi?id=62600

Add a lexing function that expects to lex an "normal" alpha numeric
identifier (that ignores keywords) so it's possible to inline the
common parsing cases. This comes out as a reasonable parsing speed
boost.

• parser/JSParser.cpp: (JSC::JSParser::nextExpectIdentifier): (JSC::JSParser::parseProperty): (JSC::JSParser::parseMemberExpression):
• parser/Lexer.cpp:
• parser/Lexer.h: (JSC::Lexer::makeIdentifier): (JSC::Lexer::lexExpectIdentifier):

File:

• trunk/Source/JavaScriptCore/parser/Lexer.h (modified) (2 diffs)

trunk/Source/JavaScriptCore/parser/Lexer.h

@@ -89 +89 @@
 
         SourceProvider* sourceProvider() const { return m_source->provider(); }
-
+        
+        JSTokenType lexExpectIdentifier(JSTokenData* lvalp, JSTokenInfo* llocp, unsigned, bool strictMode);
+        
     private:
         friend class JSGlobalData;
@@ -174 +176 @@
         return (convertHex(c1, c2) << 8) | convertHex(c3, c4);
     }
+    
+    ALWAYS_INLINE const Identifier* Lexer::makeIdentifier(const UChar* characters, size_t length)
+    {
+        return &m_arena->makeIdentifier(m_globalData, characters, length);
+    }
+
+    ALWAYS_INLINE JSTokenType Lexer::lexExpectIdentifier(JSTokenData* lvalp, JSTokenInfo* llocp, unsigned lexType, bool strictMode)
+    {
+        ASSERT((lexType & IgnoreReservedWords));
+        const UChar* start = m_code;
+        const UChar* ptr = start;
+        const UChar* end = m_codeEnd;
+        if (ptr >= end) {
+            ASSERT(ptr == end);
+            goto slowCase;
+        }
+        if (!WTF::isASCIIAlpha(*ptr))
+            goto slowCase;
+        ++ptr;
+        while (ptr < end) {
+            if (!WTF::isASCIIAlphanumeric(*ptr))
+                break;
+            ++ptr;
+        }
+
+        // Here's the shift
+        if (ptr < end) {
+            if (!WTF::isASCII(*ptr) || (*ptr == '\\') || (*ptr == '_'))
+                goto slowCase;
+            m_current = *ptr;
+        } else
+            m_current = -1;
+
+        m_code = ptr;
+
+        // Create the identifier if needed
+        if (lexType & DontBuildKeywords)
+            lvalp->ident = 0;
+        else
+            lvalp->ident = makeIdentifier(start, ptr - start);
+        llocp->line = m_lineNumber;
+        llocp->startOffset = start - m_codeStart;
+        llocp->endOffset = currentOffset();
+        m_lastToken = IDENT;
+        return IDENT;
+        
+    slowCase:
+        return lex(lvalp, llocp, lexType, strictMode);
+    }
 
 } // namespace JSC