summaryrefslogtreecommitdiff
path: root/js/src/frontend/GenerateReservedWords.py
diff options
context:
space:
mode:
Diffstat (limited to 'js/src/frontend/GenerateReservedWords.py')
-rw-r--r--js/src/frontend/GenerateReservedWords.py213
1 files changed, 213 insertions, 0 deletions
diff --git a/js/src/frontend/GenerateReservedWords.py b/js/src/frontend/GenerateReservedWords.py
new file mode 100644
index 0000000000..bd698cc5f0
--- /dev/null
+++ b/js/src/frontend/GenerateReservedWords.py
@@ -0,0 +1,213 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import re
+import sys
+
+def read_reserved_word_list(filename):
+ macro_pat = re.compile(r"^\s*macro\(([^,]+), *[^,]+, *[^\)]+\)\s*\\?$")
+
+ reserved_word_list = []
+ index = 0
+ with open(filename, 'r') as f:
+ for line in f:
+ m = macro_pat.search(line)
+ if m:
+ reserved_word_list.append((index, m.group(1)))
+ index += 1
+
+ assert(len(reserved_word_list) != 0)
+
+ return reserved_word_list
+
+def line(opt, s):
+ opt['output'].write('{}{}\n'.format(' ' * opt['indent_level'], s))
+
+def indent(opt):
+ opt['indent_level'] += 1
+
+def dedent(opt):
+ opt['indent_level'] -= 1
+
+def span_and_count_at(reserved_word_list, column):
+ assert(len(reserved_word_list) != 0);
+
+ chars_dict = {}
+ for index, word in reserved_word_list:
+ chars_dict[ord(word[column])] = True
+
+ chars = sorted(chars_dict.keys())
+ return chars[-1] - chars[0] + 1, len(chars)
+
+def optimal_switch_column(opt, reserved_word_list, columns, unprocessed_columns):
+ assert(len(reserved_word_list) != 0);
+ assert(unprocessed_columns != 0);
+
+ min_count = 0
+ min_span = 0
+ min_count_index = 0
+ min_span_index = 0
+
+ for index in range(0, unprocessed_columns):
+ span, count = span_and_count_at(reserved_word_list, columns[index])
+ assert(span != 0)
+
+ if span == 1:
+ assert(count == 1)
+ return 1, True
+
+ assert(count != 1)
+ if index == 0 or min_span > span:
+ min_span = span
+ min_span_index = index
+
+ if index == 0 or min_count > count:
+ min_count = count
+ min_count_index = index
+
+ if min_count <= opt['use_if_threshold']:
+ return min_count_index, True
+
+ return min_span_index, False
+
+def split_list_per_column(reserved_word_list, column):
+ assert(len(reserved_word_list) != 0);
+
+ column_dict = {}
+ for item in reserved_word_list:
+ index, word = item
+ per_column = column_dict.setdefault(word[column], [])
+ per_column.append(item)
+
+ return sorted(column_dict.items(), key=lambda (char, word): ord(char))
+
+def generate_letter_switch(opt, unprocessed_columns, reserved_word_list,
+ columns=None):
+ assert(len(reserved_word_list) != 0);
+
+ if not columns:
+ columns = range(0, unprocessed_columns)
+
+ if len(reserved_word_list) == 1:
+ index, word = reserved_word_list[0]
+
+ if unprocessed_columns == 0:
+ line(opt, 'JSRW_GOT_MATCH({}) /* {} */'.format(index, word))
+ return
+
+ if unprocessed_columns > opt['char_tail_test_threshold']:
+ line(opt, 'JSRW_TEST_GUESS({}) /* {} */'.format(index, word))
+ return
+
+ conds = []
+ for column in columns[0:unprocessed_columns]:
+ quoted = repr(word[column])
+ conds.append('JSRW_AT({})=={}'.format(column, quoted))
+
+ line(opt, 'if ({}) {{'.format(' && '.join(conds)))
+
+ indent(opt)
+ line(opt, 'JSRW_GOT_MATCH({}) /* {} */'.format(index, word))
+ dedent(opt)
+
+ line(opt, '}')
+ line(opt, 'JSRW_NO_MATCH()')
+ return
+
+ assert(unprocessed_columns != 0);
+
+ optimal_column_index, use_if = optimal_switch_column(opt, reserved_word_list,
+ columns,
+ unprocessed_columns)
+ optimal_column = columns[optimal_column_index]
+
+ # Make a copy to avoid breaking passed list.
+ columns = columns[:]
+ columns[optimal_column_index] = columns[unprocessed_columns - 1]
+
+ list_per_column = split_list_per_column(reserved_word_list, optimal_column)
+
+ if not use_if:
+ line(opt, 'switch (JSRW_AT({})) {{'.format(optimal_column))
+
+ for char, reserved_word_list_per_column in list_per_column:
+ quoted = repr(char)
+ if use_if:
+ line(opt, 'if (JSRW_AT({}) == {}) {{'.format(optimal_column,
+ quoted))
+ else:
+ line(opt, ' case {}:'.format(quoted))
+
+ indent(opt)
+ generate_letter_switch(opt, unprocessed_columns - 1,
+ reserved_word_list_per_column, columns)
+ dedent(opt)
+
+ if use_if:
+ line(opt, '}')
+
+ if not use_if:
+ line(opt, '}')
+
+ line(opt, 'JSRW_NO_MATCH()')
+
+def split_list_per_length(reserved_word_list):
+ assert(len(reserved_word_list) != 0);
+
+ length_dict = {}
+ for item in reserved_word_list:
+ index, word = item
+ per_length = length_dict.setdefault(len(word), [])
+ per_length.append(item)
+
+ return sorted(length_dict.items(), key=lambda (length, word): length)
+
+def generate_switch(opt, reserved_word_list):
+ assert(len(reserved_word_list) != 0);
+
+ line(opt, '/*')
+ line(opt, ' * Generating switch for the list of {} entries:'.format(len(reserved_word_list)))
+ for index, word in reserved_word_list:
+ line(opt, ' * {}'.format(word))
+ line(opt, ' */')
+
+ list_per_length = split_list_per_length(reserved_word_list)
+
+ use_if = False
+ if len(list_per_length) < opt['use_if_threshold']:
+ use_if = True
+
+ if not use_if:
+ line(opt, 'switch (JSRW_LENGTH()) {')
+
+ for length, reserved_word_list_per_length in list_per_length:
+ if use_if:
+ line(opt, 'if (JSRW_LENGTH() == {}) {{'.format(length))
+ else:
+ line(opt, ' case {}:'.format(length))
+
+ indent(opt)
+ generate_letter_switch(opt, length, reserved_word_list_per_length)
+ dedent(opt)
+
+ if use_if:
+ line(opt, '}')
+
+ if not use_if:
+ line(opt, '}')
+ line(opt, 'JSRW_NO_MATCH()')
+
+def main(output, reserved_words_h):
+ reserved_word_list = read_reserved_word_list(reserved_words_h)
+
+ opt = {
+ 'indent_level': 1,
+ 'use_if_threshold': 3,
+ 'char_tail_test_threshold': 4,
+ 'output': output
+ }
+ generate_switch(opt, reserved_word_list)
+
+if __name__ == '__main__':
+ main(sys.stdout, *sys.argv[1:])