diff --git a/bitbake/lib/bb/codeparser.py b/bitbake/lib/bb/codeparser.py
new file mode 100644
index 0000000..82a3af4
--- /dev/null
+++ b/bitbake/lib/bb/codeparser.py
@@ -0,0 +1,414 @@
+import ast
+import codegen
+import logging
+import os.path
+import bb.utils, bb.data
+from itertools import chain
+from pysh import pyshyacc, pyshlex, sherrors
+from bb.cache import MultiProcessCache
+
+
+logger = logging.getLogger('BitBake.CodeParser')
+
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+    logger.info('Importing cPickle failed.  Falling back to a very slow implementation.')
+
+
+def check_indent(codestr):
+    """If the code is indented, add a top level piece of code to 'remove' the indentation"""
+
+    i = 0
+    while codestr[i] in ["\n", "\t", " "]:
+        i = i + 1
+
+    if i == 0:
+        return codestr
+
+    if codestr[i-1] == "\t" or codestr[i-1] == " ":
+        return "if 1:\n" + codestr
+
+    return codestr
+
+
+# Basically pickle, in python 2.7.3 at least, does badly with data duplication 
+# upon pickling and unpickling. Combine this with duplicate objects and things
+# are a mess.
+#
+# When the sets are originally created, python calls intern() on the set keys
+# which significantly improves memory usage. Sadly the pickle/unpickle process
+# doesn't call intern() on the keys and results in the same strings being duplicated
+# in memory. This also means pickle will save the same string multiple times in
+# the cache file.
+#
+# By having shell and python cacheline objects with setstate/getstate, we force
+# the object creation through our own routine where we can call intern (via internSet).
+#
+# We also use hashable frozensets and ensure we use references to these so that
+# duplicates can be removed, both in memory and in the resulting pickled data.
+#
+# By playing these games, the size of the cache file shrinks dramatically
+# meaning faster load times and the reloaded cache files also consume much less
+# memory. Smaller cache files, faster load times and lower memory usage is good.
+#
+# A custom getstate/setstate using tuples is actually worth 15% cachesize by
+# avoiding duplication of the attribute names!
+
+class SetCache(object):
+    def __init__(self):
+        self.setcache = {}
+
+    def internSet(self, items):
+        
+        new = []
+        for i in items:
+            new.append(intern(i))
+        s = frozenset(new)
+        if hash(s) in self.setcache:
+            return self.setcache[hash(s)]
+        self.setcache[hash(s)] = s
+        return s
+
+codecache = SetCache()
+
+class pythonCacheLine(object):
+    def __init__(self, refs, execs, contains):
+        self.refs = codecache.internSet(refs)
+        self.execs = codecache.internSet(execs)
+        self.contains = {}
+        for c in contains:
+            self.contains[c] = codecache.internSet(contains[c])
+
+    def __getstate__(self):
+        return (self.refs, self.execs, self.contains)
+
+    def __setstate__(self, state):
+        (refs, execs, contains) = state
+        self.__init__(refs, execs, contains)
+    def __hash__(self):
+        l = (hash(self.refs), hash(self.execs))
+        for c in sorted(self.contains.keys()):
+            l = l + (c, hash(self.contains[c]))
+        return hash(l)
+    def __repr__(self):
+        return " ".join([str(self.refs), str(self.execs), str(self.contains)]) 
+
+
+class shellCacheLine(object):
+    def __init__(self, execs):
+        self.execs = codecache.internSet(execs)
+
+    def __getstate__(self):
+        return (self.execs)
+
+    def __setstate__(self, state):
+        (execs) = state
+        self.__init__(execs)
+    def __hash__(self):
+        return hash(self.execs)
+    def __repr__(self):
+        return str(self.execs)
+
+class CodeParserCache(MultiProcessCache):
+    cache_file_name = "bb_codeparser.dat"
+    CACHE_VERSION = 7
+
+    def __init__(self):
+        MultiProcessCache.__init__(self)
+        self.pythoncache = self.cachedata[0]
+        self.shellcache = self.cachedata[1]
+        self.pythoncacheextras = self.cachedata_extras[0]
+        self.shellcacheextras = self.cachedata_extras[1]
+
+        # To avoid duplication in the codeparser cache, keep
+        # a lookup of hashes of objects we already have
+        self.pythoncachelines = {}
+        self.shellcachelines = {}
+
+    def newPythonCacheLine(self, refs, execs, contains):
+        cacheline = pythonCacheLine(refs, execs, contains)
+        h = hash(cacheline)
+        if h in self.pythoncachelines:
+            return self.pythoncachelines[h]
+        self.pythoncachelines[h] = cacheline
+        return cacheline
+
+    def newShellCacheLine(self, execs):
+        cacheline = shellCacheLine(execs)
+        h = hash(cacheline)
+        if h in self.shellcachelines:
+            return self.shellcachelines[h]
+        self.shellcachelines[h] = cacheline
+        return cacheline
+
+    def init_cache(self, d):
+        MultiProcessCache.init_cache(self, d)
+
+        # cachedata gets re-assigned in the parent
+        self.pythoncache = self.cachedata[0]
+        self.shellcache = self.cachedata[1]
+
+    def create_cachedata(self):
+        data = [{}, {}]
+        return data
+
+codeparsercache = CodeParserCache()
+
+def parser_cache_init(d):
+    codeparsercache.init_cache(d)
+
+def parser_cache_save(d):
+    codeparsercache.save_extras(d)
+
+def parser_cache_savemerge(d):
+    codeparsercache.save_merge(d)
+
+Logger = logging.getLoggerClass()
+class BufferedLogger(Logger):
+    def __init__(self, name, level=0, target=None):
+        Logger.__init__(self, name)
+        self.setLevel(level)
+        self.buffer = []
+        self.target = target
+
+    def handle(self, record):
+        self.buffer.append(record)
+
+    def flush(self):
+        for record in self.buffer:
+            self.target.handle(record)
+        self.buffer = []
+
+class PythonParser():
+    getvars = (".getVar", ".appendVar", ".prependVar")
+    containsfuncs = ("bb.utils.contains", "base_contains", "bb.utils.contains_any")
+    execfuncs = ("bb.build.exec_func", "bb.build.exec_task")
+
+    def warn(self, func, arg):
+        """Warn about calls of bitbake APIs which pass a non-literal
+        argument for the variable name, as we're not able to track such
+        a reference.
+        """
+
+        try:
+            funcstr = codegen.to_source(func)
+            argstr = codegen.to_source(arg)
+        except TypeError:
+            self.log.debug(2, 'Failed to convert function and argument to source form')
+        else:
+            self.log.debug(1, self.unhandled_message % (funcstr, argstr))
+
+    def visit_Call(self, node):
+        name = self.called_node_name(node.func)
+        if name and name.endswith(self.getvars) or name in self.containsfuncs:
+            if isinstance(node.args[0], ast.Str):
+                varname = node.args[0].s
+                if name in self.containsfuncs and isinstance(node.args[1], ast.Str):
+                    if varname not in self.contains:
+                        self.contains[varname] = set()
+                    self.contains[varname].add(node.args[1].s)
+                else:                      
+                    self.references.add(node.args[0].s)
+            else:
+                self.warn(node.func, node.args[0])
+        elif name in self.execfuncs:
+            if isinstance(node.args[0], ast.Str):
+                self.var_execs.add(node.args[0].s)
+            else:
+                self.warn(node.func, node.args[0])
+        elif name and isinstance(node.func, (ast.Name, ast.Attribute)):
+            self.execs.add(name)
+
+    def called_node_name(self, node):
+        """Given a called node, return its original string form"""
+        components = []
+        while node:
+            if isinstance(node, ast.Attribute):
+                components.append(node.attr)
+                node = node.value
+            elif isinstance(node, ast.Name):
+                components.append(node.id)
+                return '.'.join(reversed(components))
+            else:
+                break
+
+    def __init__(self, name, log):
+        self.var_execs = set()
+        self.contains = {}
+        self.execs = set()
+        self.references = set()
+        self.log = BufferedLogger('BitBake.Data.PythonParser', logging.DEBUG, log)
+
+        self.unhandled_message = "in call of %s, argument '%s' is not a string literal"
+        self.unhandled_message = "while parsing %s, %s" % (name, self.unhandled_message)
+
+    def parse_python(self, node):
+        if not node or not node.strip():
+            return
+
+        h = hash(str(node))
+
+        if h in codeparsercache.pythoncache:
+            self.references = set(codeparsercache.pythoncache[h].refs)
+            self.execs = set(codeparsercache.pythoncache[h].execs)
+            self.contains = {}
+            for i in codeparsercache.pythoncache[h].contains:
+                self.contains[i] = set(codeparsercache.pythoncache[h].contains[i])
+            return
+
+        if h in codeparsercache.pythoncacheextras:
+            self.references = set(codeparsercache.pythoncacheextras[h].refs)
+            self.execs = set(codeparsercache.pythoncacheextras[h].execs)
+            self.contains = {}
+            for i in codeparsercache.pythoncacheextras[h].contains:
+                self.contains[i] = set(codeparsercache.pythoncacheextras[h].contains[i])
+            return
+
+        code = compile(check_indent(str(node)), "<string>", "exec",
+                       ast.PyCF_ONLY_AST)
+
+        for n in ast.walk(code):
+            if n.__class__.__name__ == "Call":
+                self.visit_Call(n)
+
+        self.execs.update(self.var_execs)
+
+        codeparsercache.pythoncacheextras[h] = codeparsercache.newPythonCacheLine(self.references, self.execs, self.contains)
+
+class ShellParser():
+    def __init__(self, name, log):
+        self.funcdefs = set()
+        self.allexecs = set()
+        self.execs = set()
+        self.log = BufferedLogger('BitBake.Data.%s' % name, logging.DEBUG, log)
+        self.unhandled_template = "unable to handle non-literal command '%s'"
+        self.unhandled_template = "while parsing %s, %s" % (name, self.unhandled_template)
+
+    def parse_shell(self, value):
+        """Parse the supplied shell code in a string, returning the external
+        commands it executes.
+        """
+
+        h = hash(str(value))
+
+        if h in codeparsercache.shellcache:
+            self.execs = set(codeparsercache.shellcache[h].execs)
+            return self.execs
+
+        if h in codeparsercache.shellcacheextras:
+            self.execs = set(codeparsercache.shellcacheextras[h].execs)
+            return self.execs
+
+        self._parse_shell(value)
+        self.execs = set(cmd for cmd in self.allexecs if cmd not in self.funcdefs)
+
+        codeparsercache.shellcacheextras[h] = codeparsercache.newShellCacheLine(self.execs)
+
+        return self.execs
+
+    def _parse_shell(self, value):
+        try:
+            tokens, _ = pyshyacc.parse(value, eof=True, debug=False)
+        except pyshlex.NeedMore:
+            raise sherrors.ShellSyntaxError("Unexpected EOF")
+
+        for token in tokens:
+            self.process_tokens(token)
+
+    def process_tokens(self, tokens):
+        """Process a supplied portion of the syntax tree as returned by
+        pyshyacc.parse.
+        """
+
+        def function_definition(value):
+            self.funcdefs.add(value.name)
+            return [value.body], None
+
+        def case_clause(value):
+            # Element 0 of each item in the case is the list of patterns, and
+            # Element 1 of each item in the case is the list of commands to be
+            # executed when that pattern matches.
+            words = chain(*[item[0] for item in value.items])
+            cmds  = chain(*[item[1] for item in value.items])
+            return cmds, words
+
+        def if_clause(value):
+            main = chain(value.cond, value.if_cmds)
+            rest = value.else_cmds
+            if isinstance(rest, tuple) and rest[0] == "elif":
+                return chain(main, if_clause(rest[1]))
+            else:
+                return chain(main, rest)
+
+        def simple_command(value):
+            return None, chain(value.words, (assign[1] for assign in value.assigns))
+
+        token_handlers = {
+            "and_or": lambda x: ((x.left, x.right), None),
+            "async": lambda x: ([x], None),
+            "brace_group": lambda x: (x.cmds, None),
+            "for_clause": lambda x: (x.cmds, x.items),
+            "function_definition": function_definition,
+            "if_clause": lambda x: (if_clause(x), None),
+            "pipeline": lambda x: (x.commands, None),
+            "redirect_list": lambda x: ([x.cmd], None),
+            "subshell": lambda x: (x.cmds, None),
+            "while_clause": lambda x: (chain(x.condition, x.cmds), None),
+            "until_clause": lambda x: (chain(x.condition, x.cmds), None),
+            "simple_command": simple_command,
+            "case_clause": case_clause,
+        }
+
+        for token in tokens:
+            name, value = token
+            try:
+                more_tokens, words = token_handlers[name](value)
+            except KeyError:
+                raise NotImplementedError("Unsupported token type " + name)
+
+            if more_tokens:
+                self.process_tokens(more_tokens)
+
+            if words:
+                self.process_words(words)
+
+    def process_words(self, words):
+        """Process a set of 'words' in pyshyacc parlance, which includes
+        extraction of executed commands from $() blocks, as well as grabbing
+        the command name argument.
+        """
+
+        words = list(words)
+        for word in list(words):
+            wtree = pyshlex.make_wordtree(word[1])
+            for part in wtree:
+                if not isinstance(part, list):
+                    continue
+
+                if part[0] in ('`', '$('):
+                    command = pyshlex.wordtree_as_string(part[1:-1])
+                    self._parse_shell(command)
+
+                    if word[0] in ("cmd_name", "cmd_word"):
+                        if word in words:
+                            words.remove(word)
+
+        usetoken = False
+        for word in words:
+            if word[0] in ("cmd_name", "cmd_word") or \
+               (usetoken and word[0] == "TOKEN"):
+                if "=" in word[1]:
+                    usetoken = True
+                    continue
+
+                cmd = word[1]
+                if cmd.startswith("$"):
+                    self.log.debug(1, self.unhandled_template % cmd)
+                elif cmd == "eval":
+                    command = " ".join(word for _, word in words[1:])
+                    self._parse_shell(command)
+                else:
+                    self.allexecs.add(cmd)
+                break