Changeset 249543 in webkit

Timestamp:

Sep 5, 2019 2:13:15 PM (5 years ago)

Author:

commit-queue@webkit.org

Message:

Unreviewed, rolling out r247463.
​https://bugs.webkit.org/show_bug.cgi?id=201515

JetStream2 code-load related regression (Requested by
yusukesuzuki on #webkit).

Reverted changeset:

"Keyword lookup can use memcmp to get around unaligned load
undefined behavior"
​https://bugs.webkit.org/show_bug.cgi?id=199650
​https://trac.webkit.org/changeset/247463

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• KeywordLookupGenerator.py (modified) (5 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2019-09-05  Commit Queue  <commit-queue@webkit.org>
+
+        Unreviewed, rolling out r247463.
+        https://bugs.webkit.org/show_bug.cgi?id=201515
+
+        JetStream2 code-load related regression (Requested by
+        yusukesuzuki on #webkit).
+
+        Reverted changeset:
+
+        "Keyword lookup can use memcmp to get around unaligned load
+        undefined behavior"
+        https://bugs.webkit.org/show_bug.cgi?id=199650
+        https://trac.webkit.org/changeset/247463
+
 2019-09-05  Tadeu Zagallo  <tzagallo@apple.com>
 

trunk/Source/JavaScriptCore/KeywordLookupGenerator.py

@@ -138 +138 @@
         self.weight = weight
 
-    def printSubTreeAsC(self, indent):
+    def printSubTreeAsC(self, typeName, indent):
         str = makePadding(indent)
 
         if self.value != None:
-            print(str + "if (!isIdentPartIncludingEscape(code + %d, m_codeEnd)) {" % (len(self.fullPrefix)))
+            print(str + "if (!isIdentPartIncludingEscape(code+%d, m_codeEnd)) {" % (len(self.fullPrefix)))
             print(str + "    internalShift<%d>();" % len(self.fullPrefix))
             print(str + "    if (shouldCreateIdentifier)")
@@ -156 +156 @@
                 k = trie.fullPrefix[baseIndex] + k
             test = [("'%s'" % c) for c in k]
-            base = "code + %d" % baseIndex
-            length = __builtins__.str(len(test))
-            needle = "(std::array<Char, " + length + ">{{" + ", ".join(test) + "}}).data()"
-            comparison = ("!memcmp(%s, " % (base)) + needle + ", " + length + " * sizeof(Char))"
+            if len(test) == 1:
+                comparison = "code[%d] == %s" % (baseIndex, test[0])
+            else:
+                base = "code"
+                if baseIndex > 0:
+                    base = "code + %d" % baseIndex
+                comparison = ("COMPARE_%d%sS(%s, " % (len(test), typeName, base)) + ", ".join(test) + ")"
             if itemCount == 0:
                 print(str + "if (" + comparison + ") {")
@@ -165 +168 @@
                 print(str + "} else if (" + comparison + ") {")
 
-            trie.printSubTreeAsC(indent + 4)
+            trie.printSubTreeAsC(typeName, indent + 4)
             itemCount = itemCount + 1
 
@@ -187 +190 @@
         print("static const int maxTokenLength = %d;" % (self.maxLength() + 1))
         print("")
-        print("template <typename Char>")
-        print("template <bool shouldCreateIdentifier> ALWAYS_INLINE JSTokenType Lexer<Char>::parseKeyword(JSTokenData* data)")
+        print("template <>")
+        print("template <bool shouldCreateIdentifier> ALWAYS_INLINE JSTokenType Lexer<UChar>::parseKeyword(JSTokenData* data)")
         print("{")
         print("    ASSERT(m_codeEnd - m_code >= maxTokenLength);")
         print("")
-        print("    const Char* code = m_code;")
-        self.printSubTreeAsC(4)
+        print("    const UChar* code = m_code;")
+        self.printSubTreeAsC("UCHAR", 4)
+        print("    return IDENT;")
+        print("}")
+        print("")
+        print("template <>")
+        print("template <bool shouldCreateIdentifier> ALWAYS_INLINE JSTokenType Lexer<LChar>::parseKeyword(JSTokenData* data)")
+        print("{")
+        print("    ASSERT(m_codeEnd - m_code >= maxTokenLength);")
+        print("")
+        print("    const LChar* code = m_code;")
+        self.printSubTreeAsC("CHAR", 4)
         print("    return IDENT;")
         print("}")
@@ -206 +219 @@
 trie.fillOut()
 print("// This file was generated by KeywordLookupGenerator.py.  Do not edit.")
+print("""
+#if CPU(NEEDS_ALIGNED_ACCESS)
+
+#define COMPARE_2CHARS(address, char1, char2) \\
+    (((address)[0] == char1) && ((address)[1] == char2))
+#define COMPARE_4CHARS(address, char1, char2, char3, char4) \\
+    (COMPARE_2CHARS(address, char1, char2) && COMPARE_2CHARS((address) + 2, char3, char4))
+#define COMPARE_2UCHARS(address, char1, char2) \\
+    (((address)[0] == char1) && ((address)[1] == char2))
+#define COMPARE_4UCHARS(address, char1, char2, char3, char4) \\
+    (COMPARE_2UCHARS(address, char1, char2) && COMPARE_2UCHARS((address) + 2, char3, char4))
+
+#else // CPU(NEEDS_ALIGNED_ACCESS)
+
+#if CPU(BIG_ENDIAN)
+
+#define CHARPAIR_TOUINT16(a, b) \\
+    ((((uint16_t)(a)) << 8) + (uint16_t)(b))
+#define CHARQUAD_TOUINT32(a, b, c, d) \\
+    ((((uint32_t)(CHARPAIR_TOUINT16(a, b))) << 16) + CHARPAIR_TOUINT16(c, d))
+#define UCHARPAIR_TOUINT32(a, b) \\
+    ((((uint32_t)(a)) << 16) + (uint32_t)(b))
+#define UCHARQUAD_TOUINT64(a, b, c, d) \\
+    ((((uint64_t)(UCHARQUAD_TOUINT64(a, b))) << 32) + UCHARPAIR_TOUINT32(c, d))
+
+#else // CPU(BIG_ENDIAN)
+
+#define CHARPAIR_TOUINT16(a, b) \\
+    ((((uint16_t)(b)) << 8) + (uint16_t)(a))
+#define CHARQUAD_TOUINT32(a, b, c, d) \\
+    ((((uint32_t)(CHARPAIR_TOUINT16(c, d))) << 16) + CHARPAIR_TOUINT16(a, b))
+#define UCHARPAIR_TOUINT32(a, b) \\
+    ((((uint32_t)(b)) << 16) + (uint32_t)(a))
+#define UCHARQUAD_TOUINT64(a, b, c, d) \\
+    ((((uint64_t)(UCHARPAIR_TOUINT32(c, d))) << 32) + UCHARPAIR_TOUINT32(a, b))
+
+#endif // CPU(BIG_ENDIAN)
+
+
+#define COMPARE_2CHARS(address, char1, char2) \\
+    ((reinterpret_cast<const uint16_t*>(address))[0] == CHARPAIR_TOUINT16(char1, char2))
+#define COMPARE_2UCHARS(address, char1, char2) \\
+    ((reinterpret_cast<const uint32_t*>(address))[0] == UCHARPAIR_TOUINT32(char1, char2))
+
+#if CPU(X86_64)
+
+#define COMPARE_4CHARS(address, char1, char2, char3, char4) \\
+    ((reinterpret_cast<const uint32_t*>(address))[0] == CHARQUAD_TOUINT32(char1, char2, char3, char4))
+#define COMPARE_4UCHARS(address, char1, char2, char3, char4) \\
+    ((reinterpret_cast<const uint64_t*>(address))[0] == UCHARQUAD_TOUINT64(char1, char2, char3, char4))
+
+#else // CPU(X86_64)
+
+#define COMPARE_4CHARS(address, char1, char2, char3, char4) \\
+    (COMPARE_2CHARS(address, char1, char2) && COMPARE_2CHARS((address) + 2, char3, char4))
+#define COMPARE_4UCHARS(address, char1, char2, char3, char4) \\
+    (COMPARE_2UCHARS(address, char1, char2) && COMPARE_2UCHARS((address) + 2, char3, char4))
+
+#endif // CPU(X86_64)
+
+#endif // CPU(NEEDS_ALIGNED_ACCESS)
+
+#define COMPARE_3CHARS(address, char1, char2, char3) \\
+    (COMPARE_2CHARS(address, char1, char2) && ((address)[2] == (char3)))
+#define COMPARE_3UCHARS(address, char1, char2, char3) \\
+    (COMPARE_2UCHARS(address, char1, char2) && ((address)[2] == (char3)))
+#define COMPARE_5CHARS(address, char1, char2, char3, char4, char5) \\
+    (COMPARE_4CHARS(address, char1, char2, char3, char4) && ((address)[4] == (char5)))
+#define COMPARE_5UCHARS(address, char1, char2, char3, char4, char5) \\
+    (COMPARE_4UCHARS(address, char1, char2, char3, char4) && ((address)[4] == (char5)))
+#define COMPARE_6CHARS(address, char1, char2, char3, char4, char5, char6) \\
+    (COMPARE_4CHARS(address, char1, char2, char3, char4) && COMPARE_2CHARS(address + 4, char5, char6))
+#define COMPARE_6UCHARS(address, char1, char2, char3, char4, char5, char6) \\
+    (COMPARE_4UCHARS(address, char1, char2, char3, char4) && COMPARE_2UCHARS(address + 4, char5, char6))
+#define COMPARE_7CHARS(address, char1, char2, char3, char4, char5, char6, char7) \\
+    (COMPARE_4CHARS(address, char1, char2, char3, char4) && COMPARE_4CHARS(address + 3, char4, char5, char6, char7))
+#define COMPARE_7UCHARS(address, char1, char2, char3, char4, char5, char6, char7) \\
+    (COMPARE_4UCHARS(address, char1, char2, char3, char4) && COMPARE_4UCHARS(address + 3, char4, char5, char6, char7))
+#define COMPARE_8CHARS(address, char1, char2, char3, char4, char5, char6, char7, char8) \\
+    (COMPARE_4CHARS(address, char1, char2, char3, char4) && COMPARE_4CHARS(address + 4, char5, char6, char7, char8))
+#define COMPARE_8UCHARS(address, char1, char2, char3, char4, char5, char6, char7, char8) \\
+    (COMPARE_4UCHARS(address, char1, char2, char3, char4) && COMPARE_4UCHARS(address + 4, char5, char6, char7, char8))
+""")
 
 trie.printAsC()