Merge branch 'master' into js-modules

# Conflicts:
#	modules/libpref/init/all.js

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 000000000..bd698cc5f
--- /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:])