KeywordLookupGenerator.py

   1 # Copyright (C) 2011 Apple Inc. All rights reserved.
   2 # Copyright (C) 2012 Sony Network Entertainment. All rights reserved.
   3 #
   4 # Redistribution and use in source and binary forms, with or without
   5 # modification, are permitted provided that the following conditions
   6 # are met:
   7 # 1. Redistributions of source code must retain the above copyright
   8 #    notice, this list of conditions and the following disclaimer.
   9 # 2. Redistributions in binary form must reproduce the above copyright
  10 #    notice, this list of conditions and the following disclaimer in the
  11 #    documentation and/or other materials provided with the distribution.
  12 #
  13 # THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14 # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15 # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16 # PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17 # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18 # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19 # PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20 # PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21 # OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24
  25 import sys
  26 import string
  27 import operator
  28
  29 keywordsText = open(sys.argv[1]).read()
  30
  31 # A second argument signifies that the output
  32 # should be redirected to a file
  33 redirect_to_file = len(sys.argv) > 2
  34
  35 # Change stdout to point to the file if requested
  36 if redirect_to_file:
  37     file_output = open(sys.argv[-1], "w")
  38     sys.stdout = file_output
  39
  40 # Observed weights of the most common keywords, rounded to 2.s.d
  41 keyWordWeights = {
  42     "catch": 0.01,
  43     "try": 0.01,
  44     "while": 0.01,
  45     "case": 0.01,
  46     "break": 0.01,
  47     "new": 0.01,
  48     "in": 0.01,
  49     "typeof": 0.02,
  50     "true": 0.02,
  51     "false": 0.02,
  52     "for": 0.03,
  53     "null": 0.03,
  54     "else": 0.03,
  55     "return": 0.13,
  56     "var": 0.13,
  57     "if": 0.16,
  58     "function": 0.18,
  59     "this": 0.18,
  60 }
  61
  62
  63 def allWhitespace(str):
  64     for c in str:
  65         if not(c in string.whitespace):
  66             return False
  67     return True
  68
  69
  70 def parseKeywords(keywordsText):
  71     lines = keywordsText.split("\n")
  72     lines = [line.split("#")[0] for line in lines]
  73     lines = [line for line in lines if (not allWhitespace(line))]
  74     name = lines[0].split()
  75     terminator = lines[-1]
  76     if not name[0] == "@begin":
  77         raise Exception("expected description beginning with @begin")
  78     if not terminator == "@end":
  79         raise Exception("expected description ending with @end")
  80
  81     lines = lines[1:-1]  # trim off the old heading
  82     return [line.split() for line in lines]
  83
  84
  85 def makePadding(size):
  86     str = ""
  87     for i in range(size):
  88         str = str + " "
  89     return str
  90
  91
  92 class Trie:
  93     def __init__(self, prefix):
  94         self.prefix = prefix
  95         self.keys = {}
  96         self.value = None
  97
  98     def insert(self, key, value):
  99         if len(key) == 0:
 100             self.value = value
 101             return
 102         if not (key[0] in self.keys):
 103             self.keys[key[0]] = Trie(key[0])
 104         self.keys[key[0]].insert(key[1:], value)
 105
 106     def coalesce(self):
 107         keys = {}
 108         for k, v in self.keys.items():
 109             t = v.coalesce()
 110             keys[t.prefix] = t
 111         self.keys = keys
 112         if self.value != None:
 113             return self
 114         if len(self.keys) != 1:
 115             return self
 116         # Python 3: for() loop for compatibility. Use next() when Python 2.6 is the baseline.
 117         for (prefix, suffix) in self.keys.items():
 118             res = Trie(self.prefix + prefix)
 119             res.value = suffix.value
 120             res.keys = suffix.keys
 121             return res
 122
 123     def fillOut(self, prefix=""):
 124         self.fullPrefix = prefix + self.prefix
 125         weight = 0
 126         if self.fullPrefix in keyWordWeights:
 127             weight = weight + keyWordWeights[self.fullPrefix]
 128         self.selfWeight = weight
 129         for trie in self.keys.values():
 130             trie.fillOut(self.fullPrefix)
 131             weight = weight + trie.weight
 132         self.keys = [(trie.prefix, trie) for trie in sorted(self.keys.values(), key=operator.attrgetter('weight'), reverse=True)]
 133         self.weight = weight
 134
 135     def printSubTreeAsC(self, typeName, indent):
 136         str = makePadding(indent)
 137
 138         if self.value != None:
 139             print(str + "if (!isIdentPart(code[%d])) {" % (len(self.fullPrefix)))
 140             print(str + "    internalShift<%d>();" % len(self.fullPrefix))
 141             print(str + "    if (shouldCreateIdentifier)")
 142             print(str + ("        data->ident = &m_globalData->propertyNames->%sKeyword;" % self.fullPrefix))
 143             print(str + "    return " + self.value + ";")
 144             print(str + "}")
 145         rootIndex = len(self.fullPrefix)
 146         itemCount = 0
 147         for k, trie in self.keys:
 148             baseIndex = rootIndex
 149             if (baseIndex > 0) and (len(k) == 3):
 150                 baseIndex = baseIndex - 1
 151                 k = trie.fullPrefix[baseIndex] + k
 152             test = [("'%s'" % c) for c in k]
 153             if len(test) == 1:
 154                 comparison = "code[%d] == %s" % (baseIndex, test[0])
 155             else:
 156                 base = "code"
 157                 if baseIndex > 0:
 158                     base = "code + %d" % baseIndex
 159                 comparison = ("COMPARE_%d%sS(%s, " % (len(test), typeName, base)) + ", ".join(test) + ")"
 160             if itemCount == 0:
 161                 print(str + "if (" + comparison + ") {")
 162             else:
 163                 print(str + "} else if (" + comparison + ") {")
 164
 165             trie.printSubTreeAsC(typeName, indent + 4)
 166             itemCount = itemCount + 1
 167
 168             if itemCount == len(self.keys):
 169                 print(str + "}")
 170
 171     def maxLength(self):
 172         max = len(self.fullPrefix)
 173         for (_, trie) in self.keys:
 174             l = trie.maxLength()
 175             if l > max:
 176                 max = l
 177         return max
 178
 179     def printAsC(self):
 180         print("namespace JSC {")
 181         print("")
 182         print("static ALWAYS_INLINE bool isIdentPart(LChar c);")
 183         print("static ALWAYS_INLINE bool isIdentPart(UChar c);")
 184         # max length + 1 so we don't need to do any bounds checking at all
 185         print("static const int maxTokenLength = %d;" % (self.maxLength() + 1))
 186         print("")
 187         print("template <>")
 188         print("template <bool shouldCreateIdentifier> ALWAYS_INLINE JSTokenType Lexer<UChar>::parseKeyword(JSTokenData* data)")
 189         print("{")
 190         print("    ASSERT(m_codeEnd - m_code >= maxTokenLength);")
 191         print("")
 192         print("    const UChar* code = m_code;")
 193         self.printSubTreeAsC("UCHAR", 4)
 194         print("    return IDENT;")
 195         print("}")
 196         print("")
 197         print("template <>")
 198         print("template <bool shouldCreateIdentifier> ALWAYS_INLINE JSTokenType Lexer<LChar>::parseKeyword(JSTokenData* data)")
 199         print("{")
 200         print("    ASSERT(m_codeEnd - m_code >= maxTokenLength);")
 201         print("")
 202         print("    const LChar* code = m_code;")
 203         self.printSubTreeAsC("CHAR", 4)
 204         print("    return IDENT;")
 205         print("}")
 206         print("")
 207         print("} // namespace JSC")
 208
 209 keywords = parseKeywords(keywordsText)
 210 trie = Trie("")
 211 for k, v in keywords:
 212     trie.insert(k, v)
 213 trie.coalesce()
 214 trie.fillOut()
 215 print("// This file was generated by KeywordLookupGenerator.py.  Do not edit.")
 216 print("""
 217 #if CPU(NEEDS_ALIGNED_ACCESS)
 218
 219 #define COMPARE_2CHARS(address, char1, char2) \\
 220     (((address)[0] == char1) && ((address)[1] == char2))
 221 #define COMPARE_4CHARS(address, char1, char2, char3, char4) \\
 222     (COMPARE_2CHARS(address, char1, char2) && COMPARE_2CHARS((address) + 2, char3, char4))
 223 #define COMPARE_2UCHARS(address, char1, char2) \\
 224     (((address)[0] == char1) && ((address)[1] == char2))
 225 #define COMPARE_4UCHARS(address, char1, char2, char3, char4) \\
 226     (COMPARE_2UCHARS(address, char1, char2) && COMPARE_2UCHARS((address) + 2, char3, char4))
 227
 228 #else // CPU(NEEDS_ALIGNED_ACCESS)
 229
 230 #if CPU(BIG_ENDIAN)
 231
 232 #define CHARPAIR_TOUINT16(a, b) \\
 233     ((((uint16_t)(a)) << 8) + (uint16_t)(b))
 234 #define CHARQUAD_TOUINT32(a, b, c, d) \\
 235     ((((uint32_t)(CHARPAIR_TOUINT16(a, b))) << 16) + CHARPAIR_TOUINT16(c, d))
 236 #define UCHARPAIR_TOUINT32(a, b) \\
 237     ((((uint32_t)(a)) << 16) + (uint32_t)(b))
 238 #define UCHARQUAD_TOUINT64(a, b, c, d) \\
 239     ((((uint64_t)(UCHARQUAD_TOUINT64(a, b))) << 32) + UCHARPAIR_TOUINT32(c, d))
 240
 241 #else // CPU(BIG_ENDIAN)
 242
 243 #define CHARPAIR_TOUINT16(a, b) \\
 244     ((((uint16_t)(b)) << 8) + (uint16_t)(a))
 245 #define CHARQUAD_TOUINT32(a, b, c, d) \\
 246     ((((uint32_t)(CHARPAIR_TOUINT16(c, d))) << 16) + CHARPAIR_TOUINT16(a, b))
 247 #define UCHARPAIR_TOUINT32(a, b) \\
 248     ((((uint32_t)(b)) << 16) + (uint32_t)(a))
 249 #define UCHARQUAD_TOUINT64(a, b, c, d) \\
 250     ((((uint64_t)(UCHARPAIR_TOUINT32(c, d))) << 32) + UCHARPAIR_TOUINT32(a, b))
 251
 252 #endif // CPU(BIG_ENDIAN)
 253
 254
 255 #define COMPARE_2CHARS(address, char1, char2) \\
 256     (((uint16_t*)(address))[0] == CHARPAIR_TOUINT16(char1, char2))
 257 #define COMPARE_2UCHARS(address, char1, char2) \\
 258     (((uint32_t*)(address))[0] == UCHARPAIR_TOUINT32(char1, char2))
 259
 260 #if CPU(X86_64)
 261
 262 #define COMPARE_4CHARS(address, char1, char2, char3, char4) \\
 263     (((uint32_t*)(address))[0] == CHARQUAD_TOUINT32(char1, char2, char3, char4))
 264 #define COMPARE_4UCHARS(address, char1, char2, char3, char4) \\
 265     (((uint64_t*)(address))[0] == UCHARQUAD_TOUINT64(char1, char2, char3, char4))
 266
 267 #else // CPU(X86_64)
 268
 269 #define COMPARE_4CHARS(address, char1, char2, char3, char4) \\
 270     (COMPARE_2CHARS(address, char1, char2) && COMPARE_2CHARS((address) + 2, char3, char4))
 271 #define COMPARE_4UCHARS(address, char1, char2, char3, char4) \\
 272     (COMPARE_2UCHARS(address, char1, char2) && COMPARE_2UCHARS((address) + 2, char3, char4))
 273
 274 #endif // CPU(X86_64)
 275
 276 #endif // CPU(NEEDS_ALIGNED_ACCESS)
 277
 278 #define COMPARE_3CHARS(address, char1, char2, char3) \\
 279     (COMPARE_2CHARS(address, char1, char2) && ((address)[2] == (char3)))
 280 #define COMPARE_3UCHARS(address, char1, char2, char3) \\
 281     (COMPARE_2UCHARS(address, char1, char2) && ((address)[2] == (char3)))
 282 #define COMPARE_5CHARS(address, char1, char2, char3, char4, char5) \\
 283     (COMPARE_4CHARS(address, char1, char2, char3, char4) && ((address)[4] == (char5)))
 284 #define COMPARE_5UCHARS(address, char1, char2, char3, char4, char5) \\
 285     (COMPARE_4UCHARS(address, char1, char2, char3, char4) && ((address)[4] == (char5)))
 286 #define COMPARE_6CHARS(address, char1, char2, char3, char4, char5, char6) \\
 287     (COMPARE_4CHARS(address, char1, char2, char3, char4) && COMPARE_2CHARS(address + 4, char5, char6))
 288 #define COMPARE_6UCHARS(address, char1, char2, char3, char4, char5, char6) \\
 289     (COMPARE_4UCHARS(address, char1, char2, char3, char4) && COMPARE_2UCHARS(address + 4, char5, char6))
 290 #define COMPARE_7CHARS(address, char1, char2, char3, char4, char5, char6, char7) \\
 291     (COMPARE_4CHARS(address, char1, char2, char3, char4) && COMPARE_4CHARS(address + 3, char4, char5, char6, char7))
 292 #define COMPARE_7UCHARS(address, char1, char2, char3, char4, char5, char6, char7) \\
 293     (COMPARE_4UCHARS(address, char1, char2, char3, char4) && COMPARE_4UCHARS(address + 3, char4, char5, char6, char7))
 294 #define COMPARE_8CHARS(address, char1, char2, char3, char4, char5, char6, char7, char8) \\
 295     (COMPARE_4CHARS(address, char1, char2, char3, char4) && COMPARE_4CHARS(address + 4, char5, char6, char7, char8))
 296 #define COMPARE_8UCHARS(address, char1, char2, char3, char4, char5, char6, char7, char8) \\
 297     (COMPARE_4UCHARS(address, char1, char2, char3, char4) && COMPARE_4UCHARS(address + 4, char5, char6, char7, char8))
 298 """)
 299
 300 trie.printAsC()
 301
 302 # Close the redirected file if requested
 303 if (redirect_to_file):
 304     file_output.close()
 305     sys.stdout = sys.__stdout__