[MIPS] Adding validator for MIPS architecture.

src/trusted/validator_mips/dgen/dgen_input.py

+#!/usr/bin/python
+#
+# Copyright 2012 The Native Client Authors.  All rights reserved.
+# Use of this source code is governed by a BSD-style license that can
+# be found in the LICENSE file.
+# Copyright 2012, Google Inc.
+#
+
+"""
+A simple recursive-descent parser for the table file format.
+
+The grammar implemented here is roughly (taking some liberties with whitespace
+and comment parsing):
+
+table_file ::= ( BLANK_LINE | table_def ) end_of_file ;
+table_def ::= "--" IDENT CITATION NL
+    table_header
+    ( table_row )+ ;
+table_header ::= ( IDENT "(" BITRANGE ")" )+ ;
+table_row ::= ( PATTERN )+ ACTION ;
+
+IDENT = /[a-z0-9_]+/
+CITATION = "(" /[^)]+/ ")"
+BITRANGE = /[0-9]+/ (":" /[0-9]+/)?
+PATTERN = /[10x_]+/
+ACTION = ( "=" IDENT | "->" IDENT ) ( "(" IDENT ")" )?
+NL = a newline
+BLANK_LINE = what you might expect it to be
+"""
+
+import re
+import dgen_core
+
+# These globals track the parser state.
+_in = None
+_line_no = None
+_tables = None
+_line = None
+_last_row = None
+
+
+def parse_tables(input):
+    """Entry point for the parser.  Input should be a file or file-like."""
+    global _in, _line_no, _tables
+    _in = input
+    _line_no = 0
+    _tables = []
+    next_line()
+
+    while not end_of_file():
+        blank_line() or table_def() or unexpected()
+
+    return _tables
+
+
+def blank_line():
+    if _line:
+        return False
+
+    next_line();
+    return True
+
+
+def table_def():
+    global _last_row
+
+    m = re.match(r'^-- ([^ ]+) \(([^)]+)\)', _line)
+    if not m: return False
+
+    table = dgen_core.Table(m.group(1), m.group(2))
+    next_line()
+    while blank_line(): pass
+
+    table_header(table)
+    _last_row = None
+    while not end_of_file() and not blank_line():
+        table_row(table)
+
+    _tables.append(table)
+    return True
+
+
+def table_header(table):
+    for col in _line.split():
+        m = re.match(r'^([a-z0-9_]+)\(([0-9]+)(:([0-9]+))?\)$', col, re.I)
+        if not m: raise Exception('Invalid column header: %s' % col)
+
+        hi_bit = int(m.group(2))
+        if m.group(4):
+            lo_bit = int(m.group(4))
+        else:
+            lo_bit = hi_bit
+        table.add_column(m.group(1), hi_bit, lo_bit)
+    next_line()
+
+
+def table_row(table):
+    global _last_row
+
+    row = _line.split()
+    for i in range(0, len(row)):
+        if row[i] == '"': row[i] = _last_row[i]
+    _last_row = row
+
+    action = row[-1]
+    patterns = row[:-1]
+    table.add_row(patterns, action)
+    next_line()
+
+
+def end_of_file():
+    return _line is None
+
+
+def next_line():
+    global _line_no, _line
+
+    _line_no += 1
+    _line = _in.readline()
+    if _line:
+        _line = re.sub(r'#.*', '', _line).strip()
+    else:
+        _line = None
+
+
+def unexpected():
+    raise Exception('Line %d: Unexpected line in input: %s' % (_line_no, _line))