[pypy-commit] pypy py3k: Merge default

amauryfa noreply at buildbot.pypy.org
Mon Oct 17 19:57:44 CEST 2011


Author: Amaury Forgeot d'Arc <amauryfa at gmail.com>
Branch: py3k
Changeset: r48155:a0e3eb8d4121
Date: 2011-10-17 19:56 +0200
http://bitbucket.org/pypy/pypy/changeset/a0e3eb8d4121/

Log:	Merge default

diff --git a/lib-python/modified-2.7/test/test_array.py b/lib-python/modified-2.7/test/test_array.py
--- a/lib-python/modified-2.7/test/test_array.py
+++ b/lib-python/modified-2.7/test/test_array.py
@@ -295,9 +295,10 @@
         )
 
         b = array.array(self.badtypecode())
-        self.assertRaises(TypeError, "a + b")
-
-        self.assertRaises(TypeError, "a + 'bad'")
+        with self.assertRaises(TypeError):
+            a + b
+        with self.assertRaises(TypeError):
+            a + 'bad'
 
     def test_iadd(self):
         a = array.array(self.typecode, self.example[::-1])
@@ -316,9 +317,10 @@
         )
 
         b = array.array(self.badtypecode())
-        self.assertRaises(TypeError, "a += b")
-
-        self.assertRaises(TypeError, "a += 'bad'")
+        with self.assertRaises(TypeError):
+            a += b
+        with self.assertRaises(TypeError):
+            a += 'bad'
 
     def test_mul(self):
         a = 5*array.array(self.typecode, self.example)
@@ -345,7 +347,8 @@
             array.array(self.typecode)
         )
 
-        self.assertRaises(TypeError, "a * 'bad'")
+        with self.assertRaises(TypeError):
+            a * 'bad'
 
     def test_imul(self):
         a = array.array(self.typecode, self.example)
@@ -374,7 +377,8 @@
         a *= -1
         self.assertEqual(a, array.array(self.typecode))
 
-        self.assertRaises(TypeError, "a *= 'bad'")
+        with self.assertRaises(TypeError):
+            a *= 'bad'
 
     def test_getitem(self):
         a = array.array(self.typecode, self.example)
diff --git a/lib_pypy/resource.py b/lib_pypy/resource.py
--- a/lib_pypy/resource.py
+++ b/lib_pypy/resource.py
@@ -7,7 +7,7 @@
 
 from ctypes_support import standard_c_lib as libc
 from ctypes_support import get_errno
-from ctypes import Structure, c_int, c_long, byref, sizeof, POINTER
+from ctypes import Structure, c_int, c_long, byref, POINTER
 from errno import EINVAL, EPERM
 import _structseq
 
@@ -165,7 +165,6 @@
 
 @builtinify
 def getpagesize():
-    pagesize = 0
     if _getpagesize:
         return _getpagesize()
     else:
diff --git a/pypy/config/pypyoption.py b/pypy/config/pypyoption.py
--- a/pypy/config/pypyoption.py
+++ b/pypy/config/pypyoption.py
@@ -127,7 +127,7 @@
 
 pypy_optiondescription = OptionDescription("objspace", "Object Space Options", [
     ChoiceOption("name", "Object Space name",
-                 ["std", "flow", "thunk", "dump", "taint"],
+                 ["std", "flow", "thunk", "dump"],
                  "std",
                  cmdline='--objspace -o'),
 
diff --git a/pypy/doc/__pypy__-module.rst b/pypy/doc/__pypy__-module.rst
--- a/pypy/doc/__pypy__-module.rst
+++ b/pypy/doc/__pypy__-module.rst
@@ -37,29 +37,6 @@
 .. _`thunk object space docs`: objspace-proxies.html#thunk
 .. _`interface section of the thunk object space docs`: objspace-proxies.html#thunk-interface
 
-.. broken:
-
-    Taint Object Space Functionality
-    ================================
-
-    When the taint object space is used (choose with :config:`objspace.name`),
-    the following names are put into ``__pypy__``:
-
-     - ``taint``
-     - ``is_tainted``
-     - ``untaint``
-     - ``taint_atomic``
-     - ``_taint_debug``
-     - ``_taint_look``
-     - ``TaintError``
-
-    Those are all described in the `interface section of the taint object space
-    docs`_.
-
-    For more detailed explanations and examples see the `taint object space docs`_.
-
-    .. _`taint object space docs`: objspace-proxies.html#taint
-    .. _`interface section of the taint object space docs`: objspace-proxies.html#taint-interface
 
 Transparent Proxy Functionality
 ===============================
diff --git a/pypy/doc/config/objspace.name.txt b/pypy/doc/config/objspace.name.txt
--- a/pypy/doc/config/objspace.name.txt
+++ b/pypy/doc/config/objspace.name.txt
@@ -4,7 +4,6 @@
 for normal usage):
 
   * thunk_: The thunk object space adds lazy evaluation to PyPy.
-  * taint_: The taint object space adds soft security features.
   * dump_:  Using this object spaces results in the dumpimp of all operations
     to a log.
 
@@ -12,5 +11,4 @@
 .. _`Object Space Proxies`: ../objspace-proxies.html
 .. _`Standard Object Space`: ../objspace.html#standard-object-space
 .. _thunk: ../objspace-proxies.html#thunk
-.. _taint: ../objspace-proxies.html#taint
 .. _dump: ../objspace-proxies.html#dump
diff --git a/pypy/doc/index.rst b/pypy/doc/index.rst
--- a/pypy/doc/index.rst
+++ b/pypy/doc/index.rst
@@ -309,7 +309,6 @@
 .. _`object space`: objspace.html
 .. _FlowObjSpace: objspace.html#the-flow-object-space 
 .. _`trace object space`: objspace.html#the-trace-object-space 
-.. _`taint object space`: objspace-proxies.html#taint
 .. _`thunk object space`: objspace-proxies.html#thunk
 .. _`transparent proxies`: objspace-proxies.html#tproxy
 .. _`Differences between PyPy and CPython`: cpython_differences.html
diff --git a/pypy/doc/objspace-proxies.rst b/pypy/doc/objspace-proxies.rst
--- a/pypy/doc/objspace-proxies.rst
+++ b/pypy/doc/objspace-proxies.rst
@@ -129,297 +129,6 @@
    function behaves lazily: all calls to it return a thunk object.
 
 
-.. broken right now:
-
-    .. _taint:
-
-    The Taint Object Space
-    ======================
-
-    Motivation
-    ----------
-
-    The Taint Object Space provides a form of security: "tainted objects",
-    inspired by various sources, see [D12.1]_ for a more detailed discussion. 
-
-    The basic idea of this kind of security is not to protect against
-    malicious code but to help with handling and boxing sensitive data. 
-    It covers two kinds of sensitive data: secret data which should not leak, 
-    and untrusted data coming from an external source and that must be 
-    validated before it is used.
-
-    The idea is that, considering a large application that handles these
-    kinds of sensitive data, there are typically only a small number of
-    places that need to explicitly manipulate that sensitive data; all the
-    other places merely pass it around, or do entirely unrelated things.
-
-    Nevertheless, if a large application needs to be reviewed for security,
-    it must be entirely carefully checked, because it is possible that a
-    bug at some apparently unrelated place could lead to a leak of sensitive
-    information in a way that an external attacker could exploit.  For
-    example, if any part of the application provides web services, an
-    attacker might be able to issue unexpected requests with a regular web
-    browser and deduce secret information from the details of the answers he
-    gets.  Another example is the common CGI attack where an attacker sends
-    malformed inputs and causes the CGI script to do unintended things.
-
-    An approach like that of the Taint Object Space allows the small parts
-    of the program that manipulate sensitive data to be explicitly marked.
-    The effect of this is that although these small parts still need a
-    careful security review, the rest of the application no longer does,
-    because even a bug would be unable to leak the information.
-
-    We have implemented a simple two-level model: objects are either
-    regular (untainted), or sensitive (tainted).  Objects are marked as
-    sensitive if they are secret or untrusted, and only declassified at
-    carefully-checked positions (e.g. where the secret data is needed, or
-    after the untrusted data has been fully validated).
-
-    It would be simple to extend the code for more fine-grained scales of
-    secrecy.  For example it is typical in the literature to consider
-    user-specified lattices of secrecy levels, corresponding to multiple
-    "owners" that cannot access data belonging to another "owner" unless
-    explicitly authorized to do so.
-
-    Tainting and untainting
-    -----------------------
-
-    Start a py.py with the Taint Object Space and try the following example::
-
-        $ py.py -o taint
-        >>>> from __pypy__ import taint
-        >>>> x = taint(6)
-
-        # x is hidden from now on.  We can pass it around and
-        # even operate on it, but not inspect it.  Taintness
-        # is propagated to operation results.
-
-        >>>> x
-        TaintError
-
-        >>>> if x > 5: y = 2   # see below
-        TaintError
-
-        >>>> y = x + 5         # ok
-        >>>> lst = [x, y]
-        >>>> z = lst.pop()
-        >>>> t = type(z)       # type() works too, tainted answer
-        >>>> t
-        TaintError
-        >>>> u = t is int      # even 'is' works
-        >>>> u
-        TaintError
-
-    Notice that using a tainted boolean like ``x > 5`` in an ``if``
-    statement is forbidden.  This is because knowing which path is followed
-    would give away a hint about ``x``; in the example above, if the
-    statement ``if x > 5: y = 2`` was allowed to run, we would know
-    something about the value of ``x`` by looking at the (untainted) value
-    in the variable ``y``.
-
-    Of course, there is a way to inspect tainted objects.  The basic way is
-    to explicitly "declassify" it with the ``untaint()`` function.  In an
-    application, the places that use ``untaint()`` are the places that need
-    careful security review.  To avoid unexpected objects showing up, the
-    ``untaint()`` function must be called with the exact type of the object
-    to declassify.  It will raise ``TaintError`` if the type doesn't match::
-
-        >>>> from __pypy__ import taint
-        >>>> untaint(int, x)
-        6
-        >>>> untaint(int, z)
-        11
-        >>>> untaint(bool, x > 5)
-        True
-        >>>> untaint(int, x > 5)
-        TaintError
-
-
-    Taint Bombs
-    -----------
-
-    In this area, a common problem is what to do about failing operations.
-    If an operation raises an exception when manipulating a tainted object,
-    then the very presence of the exception can leak information about the
-    tainted object itself.  Consider::
-
-        >>>> 5 / (x-6)
-
-    By checking if this raises ``ZeroDivisionError`` or not, we would know
-    if ``x`` was equal to 6 or not.  The solution to this problem in the
-    Taint Object Space is to introduce *Taint Bombs*.  They are a kind of
-    tainted object that doesn't contain a real object, but a pending
-    exception.  Taint Bombs are indistinguishable from normal tainted
-    objects to unprivileged code. See::
-
-        >>>> x = taint(6)
-        >>>> i = 5 / (x-6)     # no exception here
-        >>>> j = i + 1         # nor here
-        >>>> k = j + 5         # nor here
-        >>>> untaint(int, k)
-        TaintError
-
-    In the above example, all of ``i``, ``j`` and ``k`` contain a Taint
-    Bomb.  Trying to untaint it raises an exception - a generic
-    ``TaintError``.  What we win is that the exception gives little away,
-    and most importantly it occurs at the point where ``untaint()`` is
-    called, not where the operation failed.  This means that all calls to
-    ``untaint()`` - but not the rest of the code - must be carefully
-    reviewed for what occurs if they receive a Taint Bomb; they might catch
-    the ``TaintError`` and give the user a generic message that something
-    went wrong, if we are reasonably careful that the message or even its
-    presence doesn't give information away.  This might be a
-    problem by itself, but there is no satisfying general solution here:
-    it must be considered on a case-by-case basis.  Again, what the
-    Taint Object Space approach achieves is not solving these problems, but
-    localizing them to well-defined small parts of the application - namely,
-    around calls to ``untaint()``.
-
-    The ``TaintError`` exception deliberately does not include any
-    useful error messages, because they might give information away.
-    Of course, this makes debugging quite a bit harder; a difficult
-    problem to solve properly.  So far we have implemented a way to peek in a Taint
-    Box or Bomb, ``__pypy__._taint_look(x)``, and a "debug mode" that
-    prints the exception as soon as a Bomb is created - both write
-    information to the low-level stderr of the application, where we hope
-    that it is unlikely to be seen by anyone but the application
-    developer.
-
-
-    Taint Atomic functions
-    ----------------------
-
-    Occasionally, a more complicated computation must be performed on a
-    tainted object.  This requires first untainting the object, performing the
-    computations, and then carefully tainting the result again (including
-    hiding all exceptions into Bombs).
-
-    There is a built-in decorator that does this for you::
-
-        >>>> @__pypy__.taint_atomic
-        >>>> def myop(x, y):
-        ....     while x > 0:
-        ....         x -= y
-        ....     return x
-        ....
-        >>>> myop(42, 10)
-        -8
-        >>>> z = myop(taint(42), 10)
-        >>>> z
-        TaintError
-        >>>> untaint(int, z)
-        -8
-
-    The decorator makes a whole function behave like a built-in operation.
-    If no tainted argument is passed in, the function behaves normally.  But
-    if any of the arguments is tainted, it is automatically untainted - so
-    the function body always sees untainted arguments - and the eventual
-    result is tainted again (possibly in a Taint Bomb).
-
-    It is important for the function marked as ``taint_atomic`` to have no
-    visible side effects, as these could cause information leakage.
-    This is currently not enforced, which means that all ``taint_atomic``
-    functions have to be carefully reviewed for security (but not the
-    callers of ``taint_atomic`` functions).
-
-    A possible future extension would be to forbid side-effects on
-    non-tainted objects from all ``taint_atomic`` functions.
-
-    An example of usage: given a tainted object ``passwords_db`` that
-    references a database of passwords, we can write a function
-    that checks if a password is valid as follows::
-
-        @taint_atomic
-        def validate(passwords_db, username, password):
-            assert type(passwords_db) is PasswordDatabase
-            assert type(username) is str
-            assert type(password) is str
-            ...load username entry from passwords_db...
-            return expected_password == password
-
-    It returns a tainted boolean answer, or a Taint Bomb if something
-    went wrong.  A caller can do::
-
-        ok = validate(passwords_db, 'john', '1234')
-        ok = untaint(bool, ok)
-
-    This can give three outcomes: ``True``, ``False``, or a ``TaintError``
-    exception (with no information on it) if anything went wrong.  If even
-    this is considered giving too much information away, the ``False`` case
-    can be made indistinguishable from the ``TaintError`` case (simply by
-    raising an exception in ``validate()`` if the password is wrong).
-
-    In the above example, the security results achieved are the following:
-    as long as ``validate()`` does not leak information, no other part of
-    the code can obtain more information about a passwords database than a
-    Yes/No answer to a precise query.
-
-    A possible extension of the ``taint_atomic`` decorator would be to check
-    the argument types, as ``untaint()`` does, for the same reason: to
-    prevent bugs where a function like ``validate()`` above is accidentally
-    called with the wrong kind of tainted object, which would make it
-    misbehave.  For now, all ``taint_atomic`` functions should be
-    conservative and carefully check all assumptions on their input
-    arguments.
-
-
-    .. _`taint-interface`:
-
-    Interface
-    ---------
-
-    .. _`like a built-in operation`:
-
-    The basic rule of the Tainted Object Space is that it introduces two new
-    kinds of objects, Tainted Boxes and Tainted Bombs (which are not types
-    in the Python sense).  Each box internally contains a regular object;
-    each bomb internally contains an exception object.  An operation
-    involving Tainted Boxes is performed on the objects contained in the
-    boxes, and gives a Tainted Box or a Tainted Bomb as a result (such an
-    operation does not let an exception be raised).  An operation called
-    with a Tainted Bomb argument immediately returns the same Tainted Bomb.
-
-    In a PyPy running with (or translated with) the Taint Object Space,
-    the ``__pypy__`` module exposes the following interface:
-
-    * ``taint(obj)``
-
-        Return a new Tainted Box wrapping ``obj``.  Return ``obj`` itself
-        if it is already tainted (a Box or a Bomb).
-
-    * ``is_tainted(obj)``
-
-        Check if ``obj`` is tainted (a Box or a Bomb).
-
-    * ``untaint(type, obj)``
-
-        Untaints ``obj`` if it is tainted.  Raise ``TaintError`` if the type
-        of the untainted object is not exactly ``type``, or if ``obj`` is a
-        Bomb.
-
-    * ``taint_atomic(func)``
-
-        Return a wrapper function around the callable ``func``.  The wrapper
-        behaves `like a built-in operation`_ with respect to untainting the
-        arguments, tainting the result, and returning a Bomb.
-
-    * ``TaintError``
-
-        Exception.  On purpose, it provides no attribute or error message.
-
-    * ``_taint_debug(level)``
-
-        Set the debugging level to ``level`` (0=off).  At level 1 or above,
-        all Taint Bombs print a diagnostic message to stderr when they are
-        created.
-
-    * ``_taint_look(obj)``
-
-        For debugging purposes: prints (to stderr) the type and address of
-        the object in a Tainted Box, or prints the exception if ``obj`` is
-        a Taint Bomb.
-
-
 .. _dump:
 
 The Dump Object Space
diff --git a/pypy/interpreter/executioncontext.py b/pypy/interpreter/executioncontext.py
--- a/pypy/interpreter/executioncontext.py
+++ b/pypy/interpreter/executioncontext.py
@@ -391,8 +391,11 @@
     def decrement_ticker(self, by):
         value = self._ticker
         if self.has_bytecode_counter:    # this 'if' is constant-folded
-            value -= by
-            self._ticker = value
+            if jit.isconstant(by) and by == 0:
+                pass     # normally constant-folded too
+            else:
+                value -= by
+                self._ticker = value
         return value
 
 
diff --git a/pypy/interpreter/pyparser/pytokenizer.py b/pypy/interpreter/pyparser/pytokenizer.py
--- a/pypy/interpreter/pyparser/pytokenizer.py
+++ b/pypy/interpreter/pyparser/pytokenizer.py
@@ -226,7 +226,7 @@
                         parenlev = parenlev - 1
                         if parenlev < 0:
                             raise TokenError("unmatched '%s'" % initial, line,
-                                             lnum-1, 0, token_list)
+                                             lnum, start + 1, token_list)
                     if token in python_opmap:
                         punct = python_opmap[token]
                     else:
diff --git a/pypy/interpreter/pyparser/test/test_pyparse.py b/pypy/interpreter/pyparser/test/test_pyparse.py
--- a/pypy/interpreter/pyparser/test/test_pyparse.py
+++ b/pypy/interpreter/pyparser/test/test_pyparse.py
@@ -87,6 +87,10 @@
         assert exc.lineno == 1
         assert exc.offset == 5
         assert exc.lastlineno == 5
+        exc = py.test.raises(SyntaxError, parse, "abc)").value
+        assert exc.msg == "unmatched ')'"
+        assert exc.lineno == 1
+        assert exc.offset == 4
 
     def test_is(self):
         self.parse("x is y")
diff --git a/pypy/jit/backend/llgraph/llimpl.py b/pypy/jit/backend/llgraph/llimpl.py
--- a/pypy/jit/backend/llgraph/llimpl.py
+++ b/pypy/jit/backend/llgraph/llimpl.py
@@ -165,6 +165,7 @@
     'unicodegetitem'  : (('ref', 'int'), 'int'),
     'unicodesetitem'  : (('ref', 'int', 'int'), 'int'),
     'cast_ptr_to_int' : (('ref',), 'int'),
+    'cast_int_to_ptr' : (('int',), 'ref'),
     'debug_merge_point': (('ref', 'int'), None),
     'force_token'     : ((), 'int'),
     'call_may_force'  : (('int', 'varargs'), 'intorptr'),
@@ -875,9 +876,6 @@
     def op_new_array(self, arraydescr, count):
         return do_new_array(arraydescr.ofs, count)
 
-    def op_cast_ptr_to_int(self, descr, ptr):
-        return cast_to_int(ptr)
-
     def op_force_token(self, descr):
         opaque_frame = _to_opaque(self)
         return llmemory.cast_ptr_to_adr(opaque_frame)
diff --git a/pypy/jit/backend/llsupport/gc.py b/pypy/jit/backend/llsupport/gc.py
--- a/pypy/jit/backend/llsupport/gc.py
+++ b/pypy/jit/backend/llsupport/gc.py
@@ -45,6 +45,14 @@
     def freeing_block(self, start, stop):
         pass
 
+    def record_constptrs(self, op, gcrefs_output_list):
+        for i in range(op.numargs()):
+            v = op.getarg(i)
+            if isinstance(v, ConstPtr) and bool(v.value):
+                p = v.value
+                rgc._make_sure_does_not_move(p)
+                gcrefs_output_list.append(p)
+
 # ____________________________________________________________
 
 class GcLLDescr_boehm(GcLLDescription):
@@ -141,6 +149,14 @@
     get_funcptr_for_newstr = None
     get_funcptr_for_newunicode = None
 
+    def rewrite_assembler(self, cpu, operations, gcrefs_output_list):
+        # record all GCREFs too, because Boehm cannot see them and keep them
+        # alive if they end up as constants in the assembler
+        for op in operations:
+            self.record_constptrs(op, gcrefs_output_list)
+        return GcLLDescription.rewrite_assembler(self, cpu, operations,
+                                                 gcrefs_output_list)
+
 
 # ____________________________________________________________
 # All code below is for the hybrid or minimark GC
@@ -757,14 +773,6 @@
             funcptr(llmemory.cast_ptr_to_adr(gcref_struct),
                     llmemory.cast_ptr_to_adr(gcref_newptr))
 
-    def record_constptrs(self, op, gcrefs_output_list):
-        for i in range(op.numargs()):
-            v = op.getarg(i)
-            if isinstance(v, ConstPtr) and bool(v.value):
-                p = v.value
-                rgc._make_sure_does_not_move(p)
-                gcrefs_output_list.append(p)
-
     def rewrite_assembler(self, cpu, operations, gcrefs_output_list):
         # Perform two kinds of rewrites in parallel:
         #
diff --git a/pypy/jit/backend/test/runner_test.py b/pypy/jit/backend/test/runner_test.py
--- a/pypy/jit/backend/test/runner_test.py
+++ b/pypy/jit/backend/test/runner_test.py
@@ -1468,20 +1468,16 @@
         return u''.join(u.chars)
 
 
-    def test_casts(self):
-        py.test.skip("xxx fix or kill")
-        from pypy.rpython.lltypesystem import lltype, llmemory
-        TP = lltype.GcStruct('x')
-        x = lltype.malloc(TP)        
-        x = lltype.cast_opaque_ptr(llmemory.GCREF, x)
+    def test_cast_int_to_ptr(self):
+        res = self.execute_operation(rop.CAST_INT_TO_PTR,
+                                     [BoxInt(-17)],  'ref').value
+        assert lltype.cast_ptr_to_int(res) == -17
+
+    def test_cast_ptr_to_int(self):
+        x = lltype.cast_int_to_ptr(llmemory.GCREF, -19)
         res = self.execute_operation(rop.CAST_PTR_TO_INT,
-                                     [BoxPtr(x)],  'int').value
-        expected = self.cpu.cast_adr_to_int(llmemory.cast_ptr_to_adr(x))
-        assert rffi.get_real_int(res) == rffi.get_real_int(expected)
-        res = self.execute_operation(rop.CAST_PTR_TO_INT,
-                                     [ConstPtr(x)],  'int').value
-        expected = self.cpu.cast_adr_to_int(llmemory.cast_ptr_to_adr(x))
-        assert rffi.get_real_int(res) == rffi.get_real_int(expected)
+                                     [BoxPtr(x)], 'int').value
+        assert res == -19
 
     def test_ooops_non_gc(self):
         x = lltype.malloc(lltype.Struct('x'), flavor='raw')
@@ -2299,13 +2295,6 @@
         #
         cpu.bh_strsetitem(x, 4, ord('/'))
         assert str.chars[4] == '/'
-        #
-##        x = cpu.bh_newstr(5)
-##        y = cpu.bh_cast_ptr_to_int(x)
-##        z = cpu.bh_cast_ptr_to_int(x)
-##        y = rffi.get_real_int(y)
-##        z = rffi.get_real_int(z)
-##        assert type(y) == type(z) == int and y == z
 
     def test_sorting_of_fields(self):
         S = self.S
diff --git a/pypy/jit/backend/x86/assembler.py b/pypy/jit/backend/x86/assembler.py
--- a/pypy/jit/backend/x86/assembler.py
+++ b/pypy/jit/backend/x86/assembler.py
@@ -1387,7 +1387,8 @@
 
     def genop_same_as(self, op, arglocs, resloc):
         self.mov(arglocs[0], resloc)
-    #genop_cast_ptr_to_int = genop_same_as
+    genop_cast_ptr_to_int = genop_same_as
+    genop_cast_int_to_ptr = genop_same_as
 
     def genop_int_mod(self, op, arglocs, resloc):
         if IS_X86_32:
diff --git a/pypy/jit/backend/x86/regalloc.py b/pypy/jit/backend/x86/regalloc.py
--- a/pypy/jit/backend/x86/regalloc.py
+++ b/pypy/jit/backend/x86/regalloc.py
@@ -1152,7 +1152,8 @@
         self.possibly_free_var(op.getarg(0))
         resloc = self.force_allocate_reg(op.result)
         self.Perform(op, [argloc], resloc)
-    #consider_cast_ptr_to_int = consider_same_as
+    consider_cast_ptr_to_int = consider_same_as
+    consider_cast_int_to_ptr = consider_same_as
 
     def consider_strlen(self, op):
         args = op.getarglist()
diff --git a/pypy/jit/backend/x86/tool/viewcode.py b/pypy/jit/backend/x86/tool/viewcode.py
--- a/pypy/jit/backend/x86/tool/viewcode.py
+++ b/pypy/jit/backend/x86/tool/viewcode.py
@@ -9,7 +9,12 @@
 """
 
 import autopath
-import operator, sys, os, re, py, new
+import new
+import operator
+import py
+import re
+import sys
+import subprocess
 from bisect import bisect_left
 
 # don't use pypy.tool.udir here to avoid removing old usessions which
@@ -44,14 +49,16 @@
     f = open(tmpfile, 'wb')
     f.write(data)
     f.close()
-    g = os.popen(objdump % {
+    p = subprocess.Popen(objdump % {
         'file': tmpfile,
         'origin': originaddr,
         'backend': objdump_backend_option[backend_name],
-    }, 'r')
-    result = g.readlines()
-    g.close()
-    lines = result[6:]   # drop some objdump cruft
+    }, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    stdout, stderr = p.communicate()
+    assert not p.returncode, ('Encountered an error running objdump: %s' %
+                              stderr)
+    # drop some objdump cruft
+    lines = stdout.splitlines()[6:]
     return format_code_dump_with_labels(originaddr, lines, label_list)
 
 def format_code_dump_with_labels(originaddr, lines, label_list):
@@ -85,8 +92,12 @@
     #
     print 'loading symbols from %s...' % (filename,)
     symbols = {}
-    g = os.popen(symbollister % filename, "r")
-    for line in g:
+    p = subprocess.Popen(symbollister % filename, shell=True,
+                         stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    stdout, stderr = p.communicate()
+    assert not p.returncode, ('Encountered an error running nm: %s' %
+                              stderr)
+    for line in stdout.splitlines():
         match = re_symbolentry.match(line)
         if match:
             addr = long(match.group(1), 16)
@@ -94,7 +105,6 @@
             if name.startswith('pypy_g_'):
                 name = '\xb7' + name[7:]
             symbols[addr] = name
-    g.close()
     print '%d symbols found' % (len(symbols),)
     return symbols
 
diff --git a/pypy/jit/codewriter/jtransform.py b/pypy/jit/codewriter/jtransform.py
--- a/pypy/jit/codewriter/jtransform.py
+++ b/pypy/jit/codewriter/jtransform.py
@@ -455,6 +455,23 @@
             # the special return value None forces op.result to be considered
             # equal to op.args[0]
             return [op0, op1, None]
+        if (hints.get('promote_string') and
+            op.args[0].concretetype is not lltype.Void):
+            S = lltype.Ptr(rstr.STR)
+            assert op.args[0].concretetype == S
+            self._register_extra_helper(EffectInfo.OS_STREQ_NONNULL,
+                                        "str.eq_nonnull",
+                                        [S, S],
+                                        lltype.Signed,
+                                        EffectInfo.EF_ELIDABLE_CANNOT_RAISE)
+            descr, p = self.callcontrol.callinfocollection.callinfo_for_oopspec(
+                EffectInfo.OS_STREQ_NONNULL)
+            # XXX this is fairly ugly way of creating a constant,
+            #     however, callinfocollection has no better interface
+            c = Constant(p.adr.ptr, lltype.typeOf(p.adr.ptr))
+            op1 = SpaceOperation('str_guard_value', [op.args[0], c, descr],
+                                 op.result)
+            return [SpaceOperation('-live-', [], None), op1, None]
         else:
             log.WARNING('ignoring hint %r at %r' % (hints, self.graph))
 
@@ -783,8 +800,7 @@
 
     def rewrite_op_cast_ptr_to_int(self, op):
         if self._is_gc(op.args[0]):
-            #return op
-            raise NotImplementedError("cast_ptr_to_int")
+            return op
 
     def rewrite_op_force_cast(self, op):
         v_arg = op.args[0]
@@ -1526,6 +1542,10 @@
     def rewrite_op_jit_force_virtual(self, op):
         return self._do_builtin_call(op)
 
+    def rewrite_op_jit_is_virtual(self, op):
+        raise Exception, (
+            "'vref.virtual' should not be used from jit-visible code")
+
     def rewrite_op_jit_force_virtualizable(self, op):
         # this one is for virtualizables
         vinfo = self.get_vinfo(op.args[0])
diff --git a/pypy/jit/codewriter/test/test_jtransform.py b/pypy/jit/codewriter/test/test_jtransform.py
--- a/pypy/jit/codewriter/test/test_jtransform.py
+++ b/pypy/jit/codewriter/test/test_jtransform.py
@@ -99,6 +99,12 @@
             if i == oopspecindex:
                 return True
         return False
+    def callinfo_for_oopspec(self, oopspecindex):
+        assert oopspecindex == effectinfo.EffectInfo.OS_STREQ_NONNULL
+        class c:
+            class adr:
+                ptr = 1
+        return ('calldescr', c)
 
 class FakeBuiltinCallControl:
     def __init__(self):
@@ -119,6 +125,7 @@
              EI.OS_STR2UNICODE:([PSTR], PUNICODE),
              EI.OS_STR_CONCAT: ([PSTR, PSTR], PSTR),
              EI.OS_STR_SLICE:  ([PSTR, INT, INT], PSTR),
+             EI.OS_STREQ_NONNULL:  ([PSTR, PSTR], INT),
              EI.OS_UNI_CONCAT: ([PUNICODE, PUNICODE], PUNICODE),
              EI.OS_UNI_SLICE:  ([PUNICODE, INT, INT], PUNICODE),
              EI.OS_UNI_EQUAL:  ([PUNICODE, PUNICODE], lltype.Bool),
@@ -844,6 +851,21 @@
     assert op1.args[2] == ListOfKind('ref', [v1, v2])
     assert op1.result == v3
 
+def test_str_promote():
+    PSTR = lltype.Ptr(rstr.STR)
+    v1 = varoftype(PSTR)
+    v2 = varoftype(PSTR)
+    op = SpaceOperation('hint',
+                        [v1, Constant({'promote_string': True}, lltype.Void)],
+                        v2)
+    tr = Transformer(FakeCPU(), FakeBuiltinCallControl())
+    op0, op1, _ = tr.rewrite_operation(op)
+    assert op1.opname == 'str_guard_value'
+    assert op1.args[0] == v1
+    assert op1.args[2] == 'calldescr'
+    assert op1.result == v2
+    assert op0.opname == '-live-'
+
 def test_unicode_concat():
     # test that the oopspec is present and correctly transformed
     PSTR = lltype.Ptr(rstr.UNICODE)
diff --git a/pypy/jit/metainterp/blackhole.py b/pypy/jit/metainterp/blackhole.py
--- a/pypy/jit/metainterp/blackhole.py
+++ b/pypy/jit/metainterp/blackhole.py
@@ -2,7 +2,7 @@
 from pypy.rlib.rtimer import read_timestamp
 from pypy.rlib.rarithmetic import intmask, LONG_BIT, r_uint, ovfcheck
 from pypy.rlib.objectmodel import we_are_translated
-from pypy.rlib.debug import debug_start, debug_stop
+from pypy.rlib.debug import debug_start, debug_stop, ll_assert
 from pypy.rlib.debug import make_sure_not_resized
 from pypy.rpython.lltypesystem import lltype, llmemory, rclass
 from pypy.rpython.lltypesystem.lloperation import llop
@@ -503,6 +503,15 @@
     @arguments("r", returns="r")
     def bhimpl_cast_opaque_ptr(a):
         return a
+    @arguments("r", returns="i")
+    def bhimpl_cast_ptr_to_int(a):
+        i = lltype.cast_ptr_to_int(a)
+        ll_assert((i & 1) == 1, "bhimpl_cast_ptr_to_int: not an odd int")
+        return i
+    @arguments("i", returns="r")
+    def bhimpl_cast_int_to_ptr(i):
+        ll_assert((i & 1) == 1, "bhimpl_cast_int_to_ptr: not an odd int")
+        return lltype.cast_int_to_ptr(llmemory.GCREF, i)
 
     @arguments("i", returns="i")
     def bhimpl_int_copy(a):
@@ -523,6 +532,9 @@
     @arguments("f")
     def bhimpl_float_guard_value(a):
         pass
+    @arguments("r", "i", "d", returns="r")
+    def bhimpl_str_guard_value(a, i, d):
+        return a
 
     @arguments("self", "i")
     def bhimpl_int_push(self, a):
diff --git a/pypy/jit/metainterp/graphpage.py b/pypy/jit/metainterp/graphpage.py
--- a/pypy/jit/metainterp/graphpage.py
+++ b/pypy/jit/metainterp/graphpage.py
@@ -12,8 +12,8 @@
     def get_display_text(self):
         return None
 
-def display_loops(loops, errmsg=None, highlight_loops=()):
-    graphs = [(loop, loop in highlight_loops) for loop in loops]    
+def display_loops(loops, errmsg=None, highlight_loops={}):
+    graphs = [(loop, highlight_loops.get(loop, 0)) for loop in loops]    
     for graph, highlight in graphs:
         for op in graph.get_operations():
             if is_interesting_guard(op):
@@ -65,8 +65,7 @@
     def add_graph(self, graph, highlight=False):
         graphindex = len(self.graphs)
         self.graphs.append(graph)
-        if highlight:
-            self.highlight_graphs[graph] = True
+        self.highlight_graphs[graph] = highlight
         for i, op in enumerate(graph.get_operations()):
             self.all_operations[op] = graphindex, i
 
@@ -126,10 +125,13 @@
             self.dotgen.emit('subgraph cluster%d {' % graphindex)
         label = graph.get_display_text()
         if label is not None:
-            if self.highlight_graphs.get(graph):
-                fillcolor = '#f084c2'
+            colorindex = self.highlight_graphs.get(graph, 0)
+            if colorindex == 1:
+                fillcolor = '#f084c2'    # highlighted graph
+            elif colorindex == 2:
+                fillcolor = '#808080'    # invalidated graph
             else:
-                fillcolor = '#84f0c2'
+                fillcolor = '#84f0c2'    # normal color
             self.dotgen.emit_node(graphname, shape="octagon",
                                   label=label, fillcolor=fillcolor)
             self.pendingedges.append((graphname,
diff --git a/pypy/jit/metainterp/history.py b/pypy/jit/metainterp/history.py
--- a/pypy/jit/metainterp/history.py
+++ b/pypy/jit/metainterp/history.py
@@ -9,6 +9,7 @@
 
 from pypy.jit.metainterp.resoperation import ResOperation, rop
 from pypy.jit.codewriter import heaptracker, longlong
+from pypy.rlib.objectmodel import compute_identity_hash
 
 # ____________________________________________________________
 
@@ -104,7 +105,7 @@
     getref._annspecialcase_ = 'specialize:arg(1)'
 
     def _get_hash_(self):
-        raise NotImplementedError
+        return compute_identity_hash(self)
 
     def clonebox(self):
         raise NotImplementedError
@@ -133,6 +134,9 @@
     def _get_str(self):
         raise NotImplementedError
 
+    def same_box(self, other):
+        return self is other
+
 class AbstractDescr(AbstractValue):
     __slots__ = ()
 
@@ -241,32 +245,15 @@
     def constbox(self):
         return self
 
+    def same_box(self, other):
+        return self.same_constant(other)
+
     def same_constant(self, other):
         raise NotImplementedError
 
     def __repr__(self):
         return 'Const(%s)' % self._getrepr_()
 
-    def __eq__(self, other):
-        "NOT_RPYTHON"
-        # Remember that you should not compare Consts with '==' in RPython.
-        # Consts have no special __hash__, in order to force different Consts
-        # from being considered as different keys when stored in dicts
-        # (as they always are after translation).  Use a dict_equal_consts()
-        # to get the other behavior (i.e. using this __eq__).
-        if self.__class__ is not other.__class__:
-            return False
-        try:
-            return self.value == other.value
-        except TypeError:
-            if (isinstance(self.value, Symbolic) and
-                isinstance(other.value, Symbolic)):
-                return self.value is other.value
-            raise
-
-    def __ne__(self, other):
-        return not (self == other)
-
 
 class ConstInt(Const):
     type = INT
@@ -688,33 +675,6 @@
 
 # ____________________________________________________________
 
-def dict_equal_consts():
-    "NOT_RPYTHON"
-    # Returns a dict in which Consts that compare as equal
-    # are identified when used as keys.
-    return r_dict(dc_eq, dc_hash)
-
-def dc_eq(c1, c2):
-    return c1 == c2
-
-def dc_hash(c):
-    "NOT_RPYTHON"
-    # This is called during translation only.  Avoid using identityhash(),
-    # to avoid forcing a hash, at least on lltype objects.
-    if not isinstance(c, Const):
-        return hash(c)
-    if isinstance(c.value, Symbolic):
-        return id(c.value)
-    try:
-        if isinstance(c, ConstPtr):
-            p = lltype.normalizeptr(c.value)
-            if p is not None:
-                return hash(p._obj)
-            else:
-                return 0
-        return c._get_hash_()
-    except lltype.DelayedPointer:
-        return -2      # xxx risk of changing hash...
 
 def make_hashable_int(i):
     from pypy.rpython.lltypesystem.ll2ctypes import NotCtypesAllocatedStructure
@@ -772,6 +732,7 @@
     failed_states = None
     retraced_count = 0
     terminating = False # see TerminatingLoopToken in compile.py
+    invalidated = False
     outermost_jitdriver_sd = None
     # and more data specified by the backend when the loop is compiled
     number = -1
@@ -974,6 +935,7 @@
         self.loops = []
         self.locations = []
         self.aborted_keys = []
+        self.invalidated_token_numbers = set()
 
     def set_history(self, history):
         self.operations = history.operations
@@ -1052,7 +1014,12 @@
             if loop in loops:
                 loops.remove(loop)
             loops.append(loop)
-        display_loops(loops, errmsg, extraloops)
+        highlight_loops = dict.fromkeys(extraloops, 1)
+        for loop in loops:
+            if hasattr(loop, '_looptoken_number') and (
+                    loop._looptoken_number in self.invalidated_token_numbers):
+                highlight_loops.setdefault(loop, 2)
+        display_loops(loops, errmsg, highlight_loops)
 
 # ----------------------------------------------------------------
 
diff --git a/pypy/jit/metainterp/memmgr.py b/pypy/jit/metainterp/memmgr.py
--- a/pypy/jit/metainterp/memmgr.py
+++ b/pypy/jit/metainterp/memmgr.py
@@ -68,7 +68,8 @@
         debug_print("Loop tokens before:", oldtotal)
         max_generation = self.current_generation - (self.max_age-1)
         for looptoken in self.alive_loops.keys():
-            if 0 <= looptoken.generation < max_generation:
+            if (0 <= looptoken.generation < max_generation or
+                looptoken.invalidated):
                 del self.alive_loops[looptoken]
         newtotal = len(self.alive_loops)
         debug_print("Loop tokens freed: ", oldtotal - newtotal)
diff --git a/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py b/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py
--- a/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py
+++ b/pypy/jit/metainterp/optimizeopt/test/test_optimizebasic.py
@@ -2329,7 +2329,7 @@
         def _variables_equal(box, varname, strict):
             if varname not in virtuals:
                 if strict:
-                    assert box == oparse.getvar(varname)
+                    assert box.same_box(oparse.getvar(varname))
                 else:
                     assert box.value == oparse.getvar(varname).value
             else:
diff --git a/pypy/jit/metainterp/optimizeopt/util.py b/pypy/jit/metainterp/optimizeopt/util.py
--- a/pypy/jit/metainterp/optimizeopt/util.py
+++ b/pypy/jit/metainterp/optimizeopt/util.py
@@ -90,14 +90,11 @@
     for i in range(len(args1)):
         arg1 = args1[i]
         arg2 = args2[i]
-        if isinstance(arg1, history.Const):
-            if arg1.__class__ is not arg2.__class__:
+        if arg1 is None:
+            if arg2 is not None:
                 return False
-            if not arg1.same_constant(arg2):
-                return False
-        else:
-            if not arg1 is arg2:
-                return False
+        elif not arg1.same_box(arg2):
+            return False
     return True
 
 def args_hash(args):
@@ -106,10 +103,8 @@
     for arg in args:
         if arg is None:
             y = 17
-        elif isinstance(arg, history.Const):
+        else:
             y = arg._get_hash_()
-        else:
-            y = compute_identity_hash(arg)
         res = intmask((1000003 * res) ^ y)
     return res
 
@@ -145,9 +140,12 @@
         for i in range(op1.numargs()):
             x = op1.getarg(i)
             y = op2.getarg(i)
-            assert x == remap.get(y, y)
+            assert x.same_box(remap.get(y, y))
         if op2.result in remap:
-            assert op1.result == remap[op2.result]
+            if op2.result is None:
+                assert op1.result == remap[op2.result]
+            else:
+                assert op1.result.same_box(remap[op2.result])
         else:
             remap[op2.result] = op1.result
         if op1.getopnum() != rop.JUMP:      # xxx obscure
@@ -156,11 +154,20 @@
             assert len(op1.getfailargs()) == len(op2.getfailargs())
             if strict_fail_args:
                 for x, y in zip(op1.getfailargs(), op2.getfailargs()):
-                    assert x == remap.get(y, y)
+                    if x is None:
+                        assert remap.get(y, y) is None
+                    else:
+                        assert x.same_box(remap.get(y, y))
             else:
                 fail_args1 = set(op1.getfailargs())
                 fail_args2 = set([remap.get(y, y) for y in op2.getfailargs()])
-                assert fail_args1 == fail_args2
+                for x in fail_args1:
+                    for y in fail_args2:
+                        if x.same_box(y):
+                            fail_args2.remove(y)
+                            break
+                    else:
+                        assert False
     assert len(oplist1) == len(oplist2)
     print '-'*totwidth
     return True
diff --git a/pypy/jit/metainterp/optimizeopt/vstring.py b/pypy/jit/metainterp/optimizeopt/vstring.py
--- a/pypy/jit/metainterp/optimizeopt/vstring.py
+++ b/pypy/jit/metainterp/optimizeopt/vstring.py
@@ -587,10 +587,7 @@
             return True
         #
         if v1.is_nonnull() and v2.is_nonnull():
-            if l1box is not None and l2box is not None and (
-                l1box == l2box or (isinstance(l1box, ConstInt) and
-                                   isinstance(l2box, ConstInt) and
-                                   l1box.value == l2box.value)):
+            if l1box is not None and l2box is not None and l1box.same_box(l2box):
                 do = EffectInfo.OS_STREQ_LENGTHOK
             else:
                 do = EffectInfo.OS_STREQ_NONNULL
diff --git a/pypy/jit/metainterp/pyjitpl.py b/pypy/jit/metainterp/pyjitpl.py
--- a/pypy/jit/metainterp/pyjitpl.py
+++ b/pypy/jit/metainterp/pyjitpl.py
@@ -162,15 +162,18 @@
             if registers[i] is oldbox:
                 registers[i] = newbox
         if not we_are_translated():
-            assert oldbox not in registers[count:]
+            for b in registers[count:]:
+                assert not oldbox.same_box(b)
+                
 
     def make_result_of_lastop(self, resultbox):
         got_type = resultbox.type
-        if not we_are_translated():
-            typeof = {'i': history.INT,
-                      'r': history.REF,
-                      'f': history.FLOAT}
-            assert typeof[self.jitcode._resulttypes[self.pc]] == got_type
+        # XXX disabled for now, conflicts with str_guard_value
+        #if not we_are_translated():
+        #    typeof = {'i': history.INT,
+        #              'r': history.REF,
+        #              'f': history.FLOAT}
+        #    assert typeof[self.jitcode._resulttypes[self.pc]] == got_type
         target_index = ord(self.bytecode[self.pc-1])
         if got_type == history.INT:
             self.registers_i[target_index] = resultbox
@@ -219,6 +222,7 @@
                     'cast_float_to_int', 'cast_int_to_float',
                     'cast_float_to_singlefloat', 'cast_singlefloat_to_float',
                     'float_neg', 'float_abs',
+                    'cast_ptr_to_int', 'cast_int_to_ptr',
                     ]:
         exec py.code.Source('''
             @arguments("box")
@@ -895,6 +899,21 @@
     def _opimpl_guard_value(self, orgpc, box):
         self.implement_guard_value(orgpc, box)
 
+    @arguments("orgpc", "box", "box", "descr")
+    def opimpl_str_guard_value(self, orgpc, box, funcbox, descr):
+        if isinstance(box, Const):
+            return box     # no promotion needed, already a Const
+        else:
+            constbox = box.constbox()
+            resbox = self.do_residual_call(funcbox, descr, [box, constbox])
+            promoted_box = resbox.constbox()
+            # This is GUARD_VALUE because GUARD_TRUE assumes the existance
+            # of a label when computing resumepc
+            self.generate_guard(rop.GUARD_VALUE, resbox, [promoted_box],
+                                resumepc=orgpc)
+            self.metainterp.replace_box(box, constbox)
+            return constbox
+
     opimpl_int_guard_value = _opimpl_guard_value
     opimpl_ref_guard_value = _opimpl_guard_value
     opimpl_float_guard_value = _opimpl_guard_value
diff --git a/pypy/jit/metainterp/quasiimmut.py b/pypy/jit/metainterp/quasiimmut.py
--- a/pypy/jit/metainterp/quasiimmut.py
+++ b/pypy/jit/metainterp/quasiimmut.py
@@ -2,6 +2,7 @@
 from pypy.rpython.lltypesystem import lltype, rclass
 from pypy.rpython.annlowlevel import cast_base_ptr_to_instance
 from pypy.jit.metainterp.history import AbstractDescr
+from pypy.rlib.objectmodel import we_are_translated
 
 
 def get_mutate_field_name(fieldname):
@@ -50,13 +51,13 @@
 
 class QuasiImmut(object):
     llopaque = True
+    compress_limit = 30
     
     def __init__(self, cpu):
         self.cpu = cpu
         # list of weakrefs to the LoopTokens that must be invalidated if
         # this value ever changes
         self.looptokens_wrefs = []
-        self.compress_limit = 30
 
     def hide(self):
         qmut_ptr = self.cpu.ts.cast_instance_to_base_ref(self)
@@ -73,8 +74,12 @@
         self.looptokens_wrefs.append(wref_looptoken)
 
     def compress_looptokens_list(self):
-        self.looptokens_wrefs = [wref for wref in self.looptokens_wrefs
-                                      if wref() is not None]
+        newlist = []
+        for wref in self.looptokens_wrefs:
+            looptoken = wref()
+            if looptoken is not None and not looptoken.invalidated:
+                newlist.append(wref)
+        self.looptokens_wrefs = newlist
         self.compress_limit = (len(self.looptokens_wrefs) + 15) * 2
 
     def invalidate(self):
@@ -85,8 +90,12 @@
         self.looptokens_wrefs = []
         for wref in wrefs:
             looptoken = wref()
-            if looptoken is not None:
+            if looptoken is not None and not looptoken.invalidated:
+                looptoken.invalidated = True
                 self.cpu.invalidate_loop(looptoken)
+                if not we_are_translated():
+                    self.cpu.stats.invalidated_token_numbers.add(
+                        looptoken.number)
 
 
 class QuasiImmutDescr(AbstractDescr):
diff --git a/pypy/jit/metainterp/resoperation.py b/pypy/jit/metainterp/resoperation.py
--- a/pypy/jit/metainterp/resoperation.py
+++ b/pypy/jit/metainterp/resoperation.py
@@ -433,6 +433,8 @@
     'INT_INVERT/1',
     #
     'SAME_AS/1',      # gets a Const or a Box, turns it into another Box
+    'CAST_PTR_TO_INT/1',
+    'CAST_INT_TO_PTR/1',
     #
     'PTR_EQ/2b',
     'PTR_NE/2b',
diff --git a/pypy/jit/metainterp/test/test_ajit.py b/pypy/jit/metainterp/test/test_ajit.py
--- a/pypy/jit/metainterp/test/test_ajit.py
+++ b/pypy/jit/metainterp/test/test_ajit.py
@@ -13,7 +13,7 @@
 from pypy.rlib.jit import (JitDriver, we_are_jitted, hint, dont_look_inside,
     loop_invariant, elidable, promote, jit_debug, assert_green,
     AssertGreenFailed, unroll_safe, current_trace_length, look_inside_iff,
-    isconstant, isvirtual)
+    isconstant, isvirtual, promote_string)
 from pypy.rlib.rarithmetic import ovfcheck
 from pypy.rpython.lltypesystem import lltype, llmemory, rffi
 from pypy.rpython.ootypesystem import ootype
@@ -3440,7 +3440,6 @@
 
 class TestLLtype(BaseLLtypeTests, LLJitMixin):
     def test_tagged(self):
-        py.test.skip("implement me")
         from pypy.rlib.objectmodel import UnboxedValue
         class Base(object):
             __slots__ = ()
@@ -3492,3 +3491,35 @@
                 pc += 1
             return pc
         res = self.meta_interp(main, [False, 100, True], taggedpointers=True)
+
+    def test_rerased(self):
+        from pypy.rlib.rerased import erase_int, unerase_int, new_erasing_pair
+        eraseX, uneraseX = new_erasing_pair("X")
+        #
+        class X:
+            def __init__(self, a, b):
+                self.a = a
+                self.b = b
+        #
+        def f(i, j):
+            # 'j' should be 0 or 1, not other values
+            if j > 0:
+                e = eraseX(X(i, j))
+            else:
+                try:
+                    e = erase_int(i)
+                except OverflowError:
+                    return -42
+            if j & 1:
+                x = uneraseX(e)
+                return x.a - x.b
+            else:
+                return unerase_int(e)
+        #
+        x = self.interp_operations(f, [-128, 0], taggedpointers=True)
+        assert x == -128
+        bigint = sys.maxint//2 + 1
+        x = self.interp_operations(f, [bigint, 0], taggedpointers=True)
+        assert x == -42
+        x = self.interp_operations(f, [1000, 1], taggedpointers=True)
+        assert x == 999
diff --git a/pypy/jit/metainterp/test/test_memmgr.py b/pypy/jit/metainterp/test/test_memmgr.py
--- a/pypy/jit/metainterp/test/test_memmgr.py
+++ b/pypy/jit/metainterp/test/test_memmgr.py
@@ -18,6 +18,7 @@
 
 class FakeLoopToken:
     generation = 0
+    invalidated = False
 
 
 class _TestMemoryManager:
diff --git a/pypy/jit/metainterp/test/test_quasiimmut.py b/pypy/jit/metainterp/test/test_quasiimmut.py
--- a/pypy/jit/metainterp/test/test_quasiimmut.py
+++ b/pypy/jit/metainterp/test/test_quasiimmut.py
@@ -48,6 +48,13 @@
 
 class QuasiImmutTests(object):
 
+    def setup_method(self, meth):
+        self.prev_compress_limit = QuasiImmut.compress_limit
+        QuasiImmut.compress_limit = 1
+
+    def teardown_method(self, meth):
+        QuasiImmut.compress_limit = self.prev_compress_limit
+
     def test_simple_1(self):
         myjitdriver = JitDriver(greens=['foo'], reds=['x', 'total'])
         class Foo:
@@ -289,7 +296,7 @@
             return total
 
         res = self.meta_interp(main, [])
-        self.check_loop_count(9)
+        self.check_tree_loop_count(6)
         assert res == main()
 
     def test_change_during_running(self):
@@ -317,7 +324,7 @@
         assert f(100, 15) == 3009
         res = self.meta_interp(f, [100, 15])
         assert res == 3009
-        self.check_loops(guard_not_invalidated=2, getfield_gc=0,
+        self.check_loops(guard_not_invalidated=4, getfield_gc=0,
                          call_may_force=0, guard_not_forced=0)
 
     def test_list_simple_1(self):
@@ -453,10 +460,30 @@
         assert f(100, 15) == 3009
         res = self.meta_interp(f, [100, 15])
         assert res == 3009
-        self.check_loops(guard_not_invalidated=2, getfield_gc=0,
+        self.check_loops(guard_not_invalidated=4, getfield_gc=0,
                          getarrayitem_gc=0, getarrayitem_gc_pure=0,
                          call_may_force=0, guard_not_forced=0)
 
+    def test_invalidated_loop_is_not_used_any_more_as_target(self):
+        myjitdriver = JitDriver(greens=['foo'], reds=['x'])
+        class Foo:
+            _immutable_fields_ = ['step?']
+        @dont_look_inside
+        def residual(x, foo):
+            if x == 20:
+                foo.step = 1
+        def f(x):
+            foo = Foo()
+            foo.step = 2
+            while x > 0:
+                myjitdriver.jit_merge_point(foo=foo, x=x)
+                residual(x, foo)
+                x -= foo.step
+            return foo.step
+        res = self.meta_interp(f, [60])
+        assert res == 1
+        self.check_tree_loop_count(4)   # at least not 2 like before
+
 
 class TestLLtypeGreenFieldsTests(QuasiImmutTests, LLJitMixin):
     pass
diff --git a/pypy/jit/metainterp/test/test_resume.py b/pypy/jit/metainterp/test/test_resume.py
--- a/pypy/jit/metainterp/test/test_resume.py
+++ b/pypy/jit/metainterp/test/test_resume.py
@@ -1,3 +1,4 @@
+from __future__ import with_statement
 import py
 from pypy.rpython.lltypesystem import lltype, llmemory, rffi
 from pypy.jit.metainterp.optimizeopt.optimizer import OptValue
@@ -180,22 +181,27 @@
     reader.consume_boxes(info, bi, br, bf)
     b1s = reader.liveboxes[0]
     b2s = reader.liveboxes[1]
-    assert bi == [b1s, ConstInt(111), b1s]
-    assert br == [ConstPtr(gcrefnull), b2s]
+    assert_same(bi, [b1s, ConstInt(111), b1s])
+    assert_same(br, [ConstPtr(gcrefnull), b2s])
     bi, br, bf = [None]*2, [None]*0, [None]*0
     info = MyBlackholeInterp([lltype.Signed,
                               lltype.Signed]).get_current_position_info()
     reader.consume_boxes(info, bi, br, bf)
-    assert bi == [ConstInt(222), ConstInt(333)]
+    assert_same(bi, [ConstInt(222), ConstInt(333)])
     bi, br, bf = [None]*2, [None]*1, [None]*0
     info = MyBlackholeInterp([lltype.Signed, llmemory.GCREF,
                               lltype.Signed]).get_current_position_info()
     reader.consume_boxes(info, bi, br, bf)
     b3s = reader.liveboxes[2]
-    assert bi == [b1s, b3s]
-    assert br == [b2s]
+    assert_same(bi, [b1s, b3s])
+    assert_same(br, [b2s])
     #
 
+def assert_same(list1, list2):
+    assert len(list1) == len(list2)
+    for b1, b2 in zip(list1, list2):
+        assert b1.same_box(b2)
+
 def test_simple_read_tagged_ints():
     storage = Storage()
     storage.rd_consts = []
@@ -1023,11 +1029,11 @@
     metainterp = MyMetaInterp()
     reader = ResumeDataFakeReader(storage, newboxes, metainterp)
     lst = reader.consume_boxes()
-    assert lst == [b1t, b1t, b3t]
+    assert_same(lst, [b1t, b1t, b3t])
     lst = reader.consume_boxes()
-    assert lst == [ConstInt(2), ConstInt(3)]
+    assert_same(lst, [ConstInt(2), ConstInt(3)])
     lst = reader.consume_boxes()
-    assert lst == [b1t, ConstInt(1), b1t, b1t]
+    assert_same(lst, [b1t, ConstInt(1), b1t, b1t])
     assert metainterp.trace == []    
 
 
@@ -1044,11 +1050,11 @@
     reader = ResumeDataFakeReader(storage, newboxes, metainterp)
     lst = reader.consume_boxes()
     c1t = ConstInt(111)
-    assert lst == [c1t, b2t, b3t]
+    assert_same(lst, [c1t, b2t, b3t])
     lst = reader.consume_boxes()
-    assert lst == [ConstInt(2), ConstInt(3)]
+    assert_same(lst, [ConstInt(2), ConstInt(3)])
     lst = reader.consume_boxes()
-    assert lst == [c1t, ConstInt(1), c1t, b2t]
+    assert_same(lst, [c1t, ConstInt(1), c1t, b2t])
     assert metainterp.trace == []
 
 
@@ -1114,9 +1120,11 @@
     # check that we get the operations in 'expected', in a possibly different
     # order.
     assert len(trace) == len(expected)
-    for x in trace:
-        assert x in expected
-        expected.remove(x)
+    with CompareableConsts():
+        for x in trace:
+            assert x in expected
+            expected.remove(x)
+
     ptr = b2t.value._obj.container._as_ptr()
     assert lltype.typeOf(ptr) == lltype.Ptr(LLtypeMixin.NODE)
     assert ptr.value == 111
@@ -1126,6 +1134,18 @@
     assert ptr2.parent.value == 33
     assert ptr2.parent.next == ptr
 
+class CompareableConsts(object):
+    def __init__(self):
+        self.oldeq = None
+        
+    def __enter__(self):
+        assert self.oldeq is None
+        self.oldeq = Const.__eq__
+        Const.__eq__ = Const.same_box
+        
+    def __exit__(self, type, value, traceback):
+        Const.__eq__ = self.oldeq
+
 def test_virtual_adder_make_varray():
     b2s, b4s = [BoxPtr(), BoxInt(4)]
     c1s = ConstInt(111)
@@ -1163,8 +1183,9 @@
         (rop.SETARRAYITEM_GC, [b2t,ConstInt(1), c1s], None,
                               LLtypeMixin.arraydescr),
         ]
-    for x, y in zip(expected, trace):
-        assert x == y
+    with CompareableConsts():
+        for x, y in zip(expected, trace):
+            assert x == y
     #
     ptr = b2t.value._obj.container._as_ptr()
     assert lltype.typeOf(ptr) == lltype.Ptr(lltype.GcArray(lltype.Signed))
@@ -1207,8 +1228,9 @@
         (rop.SETFIELD_GC, [b2t, c1s],  None, LLtypeMixin.adescr),
         (rop.SETFIELD_GC, [b2t, b4t], None, LLtypeMixin.bdescr),
         ]
-    for x, y in zip(expected, trace):
-        assert x == y
+    with CompareableConsts():
+        for x, y in zip(expected, trace):
+            assert x == y
     #
     ptr = b2t.value._obj.container._as_ptr()
     assert lltype.typeOf(ptr) == lltype.Ptr(LLtypeMixin.S)
diff --git a/pypy/jit/metainterp/test/test_string.py b/pypy/jit/metainterp/test/test_string.py
--- a/pypy/jit/metainterp/test/test_string.py
+++ b/pypy/jit/metainterp/test/test_string.py
@@ -3,7 +3,8 @@
 from pypy.jit.codewriter.policy import StopAtXPolicy
 from pypy.jit.metainterp.test.support import LLJitMixin, OOJitMixin
 from pypy.rlib.debug import debug_print
-from pypy.rlib.jit import JitDriver, dont_look_inside, we_are_jitted
+from pypy.rlib.jit import JitDriver, dont_look_inside, we_are_jitted,\
+     promote_string
 from pypy.rlib.rstring import StringBuilder
 from pypy.rpython.ootypesystem import ootype
 
@@ -507,6 +508,18 @@
                           'jump': 1, 'int_is_true': 1,
                           'guard_not_invalidated': 1})
 
+    def test_promote_string(self):
+        driver = JitDriver(greens = [], reds = ['n'])
+        
+        def f(n):
+            while n < 21:
+                driver.jit_merge_point(n=n)
+                promote_string(str(n % 3))
+                n += 1
+            return 0
+
+        self.meta_interp(f, [0])
+        self.check_loops(call=3 + 1) # one for int2str
 
 #class TestOOtype(StringTests, OOJitMixin):
 #    CALL = "oosend"
diff --git a/pypy/jit/metainterp/test/test_virtualref.py b/pypy/jit/metainterp/test/test_virtualref.py
--- a/pypy/jit/metainterp/test/test_virtualref.py
+++ b/pypy/jit/metainterp/test/test_virtualref.py
@@ -3,6 +3,7 @@
 from pypy.rpython.llinterp import LLException
 from pypy.rlib.jit import JitDriver, dont_look_inside, vref_None
 from pypy.rlib.jit import virtual_ref, virtual_ref_finish, InvalidVirtualRef
+from pypy.rlib.jit import non_virtual_ref
 from pypy.rlib.objectmodel import compute_unique_id
 from pypy.jit.metainterp.test.support import LLJitMixin, OOJitMixin, _get_jitcodes
 from pypy.jit.metainterp.resoperation import rop
@@ -595,6 +596,65 @@
         res = self.meta_interp(fn, [10])
         assert res == 6
 
+    def test_is_virtual(self):
+        myjitdriver = JitDriver(greens=[], reds=['n', 'res1'])
+        class X:
+            pass
+        @dont_look_inside
+        def residual(vref):
+            return vref.virtual
+        #
+        def f(n):
+            res1 = -42
+            while n > 0:
+                myjitdriver.jit_merge_point(n=n, res1=res1)
+                x = X()
+                vref = virtual_ref(x)
+                res1 = residual(vref)
+                virtual_ref_finish(vref, x)
+                n -= 1
+            return res1
+        #
+        res = self.meta_interp(f, [10])
+        assert res == 1
+
+    def test_is_not_virtual_none(self):
+        myjitdriver = JitDriver(greens=[], reds=['n', 'res1'])
+        @dont_look_inside
+        def residual(vref):
+            return vref.virtual
+        #
+        def f(n):
+            res1 = -42
+            while n > 0:
+                myjitdriver.jit_merge_point(n=n, res1=res1)
+                res1 = residual(vref_None)
+                n -= 1
+            return res1
+        #
+        res = self.meta_interp(f, [10])
+        assert res == 0
+
+    def test_is_not_virtual_non_none(self):
+        myjitdriver = JitDriver(greens=[], reds=['n', 'res1'])
+        class X:
+            pass
+        @dont_look_inside
+        def residual(vref):
+            return vref.virtual
+        #
+        def f(n):
+            res1 = -42
+            while n > 0:
+                myjitdriver.jit_merge_point(n=n, res1=res1)
+                x = X()
+                res1 = residual(non_virtual_ref(x))
+                n -= 1
+            return res1
+        #
+        res = self.meta_interp(f, [10])
+        assert res == 0
+
 
 class TestLLtype(VRefTests, LLJitMixin):
     pass
diff --git a/pypy/jit/metainterp/virtualref.py b/pypy/jit/metainterp/virtualref.py
--- a/pypy/jit/metainterp/virtualref.py
+++ b/pypy/jit/metainterp/virtualref.py
@@ -39,6 +39,7 @@
     def replace_force_virtual_with_call(self, graphs):
         # similar to rvirtualizable2.replace_force_virtualizable_with_call().
         c_force_virtual_ptr = None
+        c_is_virtual_ptr = None
         force_virtual_count = 0
         for graph in graphs:
             for block in graph.iterblocks():
@@ -52,6 +53,13 @@
                         op.opname = 'direct_call'
                         op.args = [c_force_virtual_ptr, op.args[0]]
                         force_virtual_count += 1
+                    #
+                    if op.opname == 'jit_is_virtual':
+                        if c_is_virtual_ptr is None:
+                            c_is_virtual_ptr = self.get_is_virtual_fnptr()
+                        #
+                        op.opname = 'direct_call'
+                        op.args = [c_is_virtual_ptr, op.args[0]]
         #
         if c_force_virtual_ptr is not None:
             log("replaced %d 'jit_force_virtual' with %r" % (force_virtual_count,
@@ -129,6 +137,17 @@
             force_virtual_if_necessary)
         return inputconst(lltype.typeOf(funcptr), funcptr)
 
+    def get_is_virtual_fnptr(self):
+        #
+        def is_virtual(inst):
+            if not inst:
+                return False
+            return inst.typeptr == self.jit_virtual_ref_vtable
+        #
+        FUNC = lltype.FuncType([rclass.OBJECTPTR], lltype.Bool)
+        funcptr = self.warmrunnerdesc.helper_func(lltype.Ptr(FUNC), is_virtual)
+        return inputconst(lltype.typeOf(funcptr), funcptr)
+
     def force_virtual(self, inst):
         vref = lltype.cast_pointer(lltype.Ptr(self.JIT_VIRTUAL_REF), inst)
         token = vref.virtual_token
diff --git a/pypy/jit/metainterp/warmstate.py b/pypy/jit/metainterp/warmstate.py
--- a/pypy/jit/metainterp/warmstate.py
+++ b/pypy/jit/metainterp/warmstate.py
@@ -178,7 +178,7 @@
         if self.compiled_merge_points_wref is not None:
             for wref in self.compiled_merge_points_wref:
                 looptoken = wref()
-                if looptoken is not None:
+                if looptoken is not None and not looptoken.invalidated:
                     result.append(looptoken)
         return result
 
diff --git a/pypy/module/__builtin__/__init__.py b/pypy/module/__builtin__/__init__.py
--- a/pypy/module/__builtin__/__init__.py
+++ b/pypy/module/__builtin__/__init__.py
@@ -22,6 +22,9 @@
         'any'           : 'app_functional.any',
         'all'           : 'app_functional.all',
         'sum'           : 'app_functional.sum',
+        'map'           : 'app_functional.map',
+        'reduce'        : 'app_functional.reduce',
+        'filter'        : 'app_functional.filter',
         'vars'          : 'app_inspect.vars',
         'dir'           : 'app_inspect.dir',
 
@@ -85,11 +88,8 @@
         'enumerate'     : 'functional.W_Enumerate',
         'min'           : 'functional.min',
         'max'           : 'functional.max',
-        'map'           : 'functional.map',
         'zip'           : 'functional.zip',
-        'reduce'        : 'functional.reduce',
         'reversed'      : 'functional.reversed',
-        'filter'        : 'functional.filter',
         'super'         : 'descriptor.W_Super',
         'staticmethod'  : 'descriptor.StaticMethod',
         'classmethod'   : 'descriptor.ClassMethod',
@@ -118,7 +118,7 @@
            builtin = space.interpclass_w(w_builtin)
            if isinstance(builtin, module.Module):
                return builtin
-       # no builtin! make a default one.  Given them None, at least.
+       # no builtin! make a default one.  Give them None, at least.
        builtin = module.Module(space, None)
        space.setitem(builtin.w_dict, space.wrap('None'), space.w_None)
        return builtin
diff --git a/pypy/module/__builtin__/app_functional.py b/pypy/module/__builtin__/app_functional.py
--- a/pypy/module/__builtin__/app_functional.py
+++ b/pypy/module/__builtin__/app_functional.py
@@ -48,4 +48,118 @@
         # Very intentionally *not* +=, that would have different semantics if
         # start was a mutable type, such as a list
         last = last + x
-    return last
\ No newline at end of file
+    return last
+
+def map(func, *collections):
+    """map(function, sequence[, sequence, ...]) -> list
+
+Return a list of the results of applying the function to the items of
+the argument sequence(s).  If more than one sequence is given, the
+function is called with an argument list consisting of the corresponding
+item of each sequence, substituting None for missing values when not all
+sequences have the same length.  If the function is None, return a list of
+the items of the sequence (or a list of tuples if more than one sequence)."""
+    if not collections:
+        raise TypeError("map() requires at least two arguments")
+    num_collections = len(collections)
+    none_func = func is None
+    if num_collections == 1:
+        if none_func:
+            return list(collections[0])
+        else:
+            # Special case for the really common case of a single collection,
+            # this can be eliminated if we could unroll that loop that creates
+            # `args` based on whether or not len(collections) was constant
+            result = []
+            for item in collections[0]:
+                result.append(func(item))
+            return result
+    result = []
+    # Pair of (iterator, has_finished)
+    iterators = [(iter(seq), False) for seq in collections]
+    while True:
+        cont = False
+        args = []
+        for idx, (iterator, has_finished) in enumerate(iterators):
+            val = None
+            if not has_finished:
+                try:
+                    val = next(iterator)
+                except StopIteration:
+                    iterators[idx] = (None, True)
+                else:
+                    cont = True
+            args.append(val)
+        args = tuple(args)
+        if cont:
+            if none_func:
+                result.append(args)
+            else:
+                result.append(func(*args))
+        else:
+            return result
+
+sentinel = object()
+
+def reduce(func, sequence, initial=sentinel):
+    """reduce(function, sequence[, initial]) -> value
+
+Apply a function of two arguments cumulatively to the items of a sequence,
+from left to right, so as to reduce the sequence to a single value.
+For example, reduce(lambda x, y: x+y, [1, 2, 3, 4, 5]) calculates
+((((1+2)+3)+4)+5).  If initial is present, it is placed before the items
+of the sequence in the calculation, and serves as a default when the
+sequence is empty."""
+    iterator = iter(sequence)
+    if initial is sentinel:
+        try:
+            initial = next(iterator)
+        except StopIteration:
+            raise TypeError("reduce() of empty sequence with no initial value")
+    result = initial
+    for item in iterator:
+        result = func(result, item)
+    return result
+
+def filter(func, seq):
+    """filter(function or None, sequence) -> list, tuple, or string
+
+Return those items of sequence for which function(item) is true.  If
+function is None, return the items that are true.  If sequence is a tuple
+or string, return the same type, else return a list."""
+    if func is None:
+        func = bool
+    if isinstance(seq, str):
+        return _filter_string(func, seq, str)
+    elif isinstance(seq, unicode):
+        return _filter_string(func, seq, unicode)
+    elif isinstance(seq, tuple):
+        return _filter_tuple(func, seq)
+    result = []
+    for item in seq:
+        if func(item):
+            result.append(item)
+    return result
+
+def _filter_string(func, string, str_type):
+    if func is bool and type(string) is str_type:
+        return string
+    result = []
+    for i in range(len(string)):
+        # You must call __getitem__ on the strings, simply iterating doesn't
+        # work :/
+        item = string[i]
+        if func(item):
+            if not isinstance(item, str_type):
+                raise TypeError("__getitem__ returned a non-string type")
+            result.append(item)
+    return str_type().join(result)
+
+def _filter_tuple(func, seq):
+    result = []
+    for i in range(len(seq)):
+        # Again, must call __getitem__, at least there are tests.
+        item = seq[i]
+        if func(item):
+            result.append(item)
+    return tuple(result)
\ No newline at end of file
diff --git a/pypy/module/__builtin__/compiling.py b/pypy/module/__builtin__/compiling.py
--- a/pypy/module/__builtin__/compiling.py
+++ b/pypy/module/__builtin__/compiling.py
@@ -82,8 +82,8 @@
         raise OperationError(space.w_TypeError,
               w('eval() arg 1 must be a string or code object'))
 
-    caller = space.getexecutioncontext().gettopframe_nohidden()
     if space.is_w(w_globals, space.w_None):
+        caller = space.getexecutioncontext().gettopframe_nohidden()
         if caller is None:
             w_globals = space.newdict()
             if space.is_w(w_locals, space.w_None):
@@ -95,14 +95,10 @@
     elif space.is_w(w_locals, space.w_None):
         w_locals = w_globals
 
-    try:
-        space.getitem(w_globals, space.wrap('__builtins__'))
-    except OperationError, e:
-        if not e.match(space, space.w_KeyError):
-            raise
-        if caller is not None:
-            w_builtin = space.builtin.pick_builtin(caller.w_globals)
-            space.setitem(w_globals, space.wrap('__builtins__'), w_builtin)
+    # xxx removed: adding '__builtins__' to the w_globals dict, if there
+    # is none.  This logic was removed as costly (it requires to get at
+    # the gettopframe_nohidden()).  I bet no test fails, and it's a really
+    # obscure case.
 
     return codeobj.exec_code(space, w_globals, w_locals)
 
diff --git a/pypy/module/__builtin__/functional.py b/pypy/module/__builtin__/functional.py
--- a/pypy/module/__builtin__/functional.py
+++ b/pypy/module/__builtin__/functional.py
@@ -116,118 +116,6 @@
     """
     return min_max(space, __args__, "min")
 
- at unwrap_spec(collections_w="args_w")
-def map(space, w_func, collections_w):
-    """does 3 separate things, hence this enormous docstring.
-       1.  if function is None, return a list of tuples, each with one
-           item from each collection.  If the collections have different
-           lengths,  shorter ones are padded with None.
-
-       2.  if function is not None, and there is only one collection,
-           apply function to every item in the collection and return a
-           list of the results.
-
-       3.  if function is not None, and there are several collections,
-           repeatedly call the function with one argument from each
-           collection.  If the collections have different lengths,
-           shorter ones are padded with None
-    """
-    if not collections_w:
-        msg = "map() requires at least two arguments"
-        raise OperationError(space.w_TypeError, space.wrap(msg))
-    none_func = space.is_w(w_func, space.w_None)
-    if len(collections_w) == 1:
-        w_collection = collections_w[0]
-        if none_func:
-            result_w = space.unpackiterable(w_collection)
-        else:
-            result_w = map_single_collection(space, w_func, w_collection)
-    else:
-        result_w = map_multiple_collections(space, w_func, collections_w,
-                                            none_func)
-    return space.newlist(result_w)
-
-def map_single_collection(space, w_func, w_collection):
-    """Special case for 'map(func, coll)', where 'func' is not None and there
-    is only one 'coll' argument."""
-    w_iter = space.iter(w_collection)
-    # xxx special hacks for speed
-    from pypy.interpreter import function, pycode
-    if isinstance(w_func, function.Function):
-        # xxx compatibility issue: what if func_code is modified in the
-        # middle of running map()??  That's far too obscure for me to care...
-        code = w_func.getcode()
-        fast_natural_arity = code.fast_natural_arity
-        if fast_natural_arity == (1|pycode.PyCode.FLATPYCALL):
-            assert isinstance(code, pycode.PyCode)
-            return map_single_user_function(code, w_func, w_iter)
-    # /xxx end of special hacks
-    return map_single_other_callable(space, w_func, w_iter)
-
-def map_single_other_callable(space, w_func, w_iter):
-    result_w = []
-    while True:
-        try:
-            w_item = space.next(w_iter)
-        except OperationError, e:
-            if not e.match(space, space.w_StopIteration):
-                raise
-            break
-        result_w.append(space.call_function(w_func, w_item))
-    return result_w
-map_single_other_callable._dont_inline_ = True
-
-from pypy.rlib.jit import JitDriver
-mapjitdriver = JitDriver(greens = ['code'],
-                         reds = ['w_func', 'w_iter', 'result_w'])
-def map_single_user_function(code, w_func, w_iter):
-    result_w = []
-    while True:
-        mapjitdriver.can_enter_jit(code=code, w_func=w_func,
-                                   w_iter=w_iter, result_w=result_w)
-        mapjitdriver.jit_merge_point(code=code, w_func=w_func,
-                                     w_iter=w_iter, result_w=result_w)
-        space = w_func.space
-        try:
-            w_item = space.next(w_iter)
-        except OperationError, e:
-            if not e.match(space, space.w_StopIteration):
-                raise
-            break
-        new_frame = space.createframe(code, w_func.w_func_globals,
-                                      w_func)
-        new_frame.locals_stack_w[0] = w_item
-        w_res = new_frame.run()
-        result_w.append(w_res)
-    return result_w
-
-def map_multiple_collections(space, w_func, collections_w, none_func):
-    result_w = []
-    iterators_w = [space.iter(w_seq) for w_seq in collections_w]
-    num_iterators = len(iterators_w)
-    while True:
-        cont = False
-        args_w = [space.w_None] * num_iterators
-        for i in range(num_iterators):
-            if iterators_w[i] is not None:
-                try:
-                    args_w[i] = space.next(iterators_w[i])
-                except OperationError, e:
-                    if not e.match(space, space.w_StopIteration):
-                        raise
-                    iterators_w[i] = None
-                else:
-                    cont = True
-        if not cont:
-            break
-        w_args = space.newtuple(args_w)
-        if none_func:
-            w_res = w_args
-        else:
-            w_res = space.call(w_func, w_args)
-        result_w.append(w_res)
-    return result_w
-
 @unwrap_spec(sequences_w="args_w")
 def zip(space, sequences_w):
     """Return a list of tuples, where the nth tuple contains every nth item of
@@ -249,90 +137,6 @@
             return space.newlist(result_w)
         result_w.append(space.newtuple(items_w))
 
-def reduce(space, w_func, w_sequence, w_initial=NoneNotWrapped):
-    """ Apply function of two arguments cumulatively to the items of sequence,
-        from left to right, so as to reduce the sequence to a single value.
-        Optionally begin with an initial value.
-    """
-    w_iter = space.iter(w_sequence)
-    if w_initial is None:
-        try:
-            w_initial = space.next(w_iter)
-        except OperationError, e:
-            if e.match(space, space.w_StopIteration):
-                msg = "reduce() of empty sequence with no initial value"
-                raise OperationError(space.w_TypeError, space.wrap(msg))
-            raise
-    w_result = w_initial
-    while True:
-        try:
-            w_next = space.next(w_iter)
-        except OperationError, e:
-            if not e.match(space, space.w_StopIteration):
-                raise
-            break
-        w_result = space.call_function(w_func, w_result, w_next)
-    return w_result
-
-def filter(space, w_func, w_seq):
-    """construct a list of those elements of collection for which function
-       is True.  If function is None, then return the items in the sequence
-       which are True.
-    """
-    if space.is_true(space.isinstance(w_seq, space.w_str)):
-        return _filter_string(space, w_func, w_seq, space.w_str)
-    if space.is_true(space.isinstance(w_seq, space.w_unicode)):
-        return _filter_string(space, w_func, w_seq, space.w_unicode)
-    if space.is_true(space.isinstance(w_seq, space.w_tuple)):
-        return _filter_tuple(space, w_func, w_seq)
-    w_iter = space.iter(w_seq)
-    result_w = []
-    none_func = space.is_w(w_func, space.w_None)
-    while True:
-        try:
-            w_next = space.next(w_iter)
-        except OperationError, e:
-            if not e.match(space, space.w_StopIteration):
-                raise
-            break
-        if none_func:
-            w_keep = w_next
-        else:
-            w_keep = space.call_function(w_func, w_next)
-        if space.is_true(w_keep):
-            result_w.append(w_next)
-    return space.newlist(result_w)
-
-def _filter_tuple(space, w_func, w_tuple):
-    none_func = space.is_w(w_func, space.w_None)
-    length = space.len_w(w_tuple)
-    result_w = []
-    for i in range(length):
-        w_item = space.getitem(w_tuple, space.wrap(i))
-        if none_func:
-            w_keep = w_item
-        else:
-            w_keep = space.call_function(w_func, w_item)
-        if space.is_true(w_keep):
-            result_w.append(w_item)
-    return space.newtuple(result_w)
-
-def _filter_string(space, w_func, w_string, w_str_type):
-    none_func = space.is_w(w_func, space.w_None)
-    if none_func and space.is_w(space.type(w_string), w_str_type):
-        return w_string
-    length = space.len_w(w_string)
-    result_w = []
-    for i in range(length):
-        w_item = space.getitem(w_string, space.wrap(i))
-        if none_func or space.is_true(space.call_function(w_func, w_item)):
-            if not space.is_true(space.isinstance(w_item, w_str_type)):
-                msg = "__getitem__ returned a non-string type"
-                raise OperationError(space.w_TypeError, space.wrap(msg))
-            result_w.append(w_item)
-    w_empty = space.call_function(w_str_type)
-    return space.call_method(w_empty, "join", space.newlist(result_w))
-
 class W_Enumerate(Wrappable):
 
     def __init__(self, w_iter, w_start):
diff --git a/pypy/module/__builtin__/test/test_functional.py b/pypy/module/__builtin__/test/test_functional.py
--- a/pypy/module/__builtin__/test/test_functional.py
+++ b/pypy/module/__builtin__/test/test_functional.py
@@ -147,7 +147,7 @@
        assert list(range(A())) == [0, 1, 2, 3, 4]
        assert list(range(0, A())) == [0, 1, 2, 3, 4]
        assert list(range(0, 10, A())) == [0, 5]
- 
+
    def test_range_float(self):
       assert list(range(0.1, 2.0, 1.1)) == [0, 1]
 
diff --git a/pypy/module/_continuation/interp_continuation.py b/pypy/module/_continuation/interp_continuation.py
--- a/pypy/module/_continuation/interp_continuation.py
+++ b/pypy/module/_continuation/interp_continuation.py
@@ -19,6 +19,11 @@
         #  - normal:      self.sthread != None, not is_empty_handle(self.h)
         #  - finished:    self.sthread != None, is_empty_handle(self.h)
 
+    def __del__(self):
+        sthread = self.sthread
+        if sthread is not None and not sthread.is_empty_handle(self.h):
+            sthread.destroy(self.h)
+
     def check_sthread(self):
         ec = self.space.getexecutioncontext()
         if ec.stacklet_thread is not self.sthread:
@@ -28,6 +33,8 @@
     def descr_init(self, w_callable, __args__):
         if self.sthread is not None:
             raise geterror(self.space, "continulet already __init__ialized")
+        sthread = build_sthread(self.space)
+        workaround_disable_jit(sthread)
         #
         # hackish: build the frame "by hand", passing it the correct arguments
         space = self.space
@@ -41,7 +48,6 @@
         self.bottomframe = bottomframe
         #
         global_state.origin = self
-        sthread = build_sthread(self.space)
         self.sthread = sthread
         h = sthread.new(new_stacklet_callback)
         post_switch(sthread, h)
@@ -71,6 +77,7 @@
                 global_state.clear()
                 raise geterror(self.space, "continulet already finished")
         self.check_sthread()
+        workaround_disable_jit(self.sthread)
         #
         global_state.origin = self
         if to is None:
@@ -259,6 +266,16 @@
         sthread = ec.stacklet_thread = SThread(space, ec)
     return sthread
 
+def workaround_disable_jit(sthread):
+    # A bad workaround to kill the JIT anywhere in this thread.
+    # This forces all the frames.  It's a bad workaround because
+    # it takes O(depth) time, and it will cause some "abort:
+    # vable escape" in the JIT.  The goal is to prevent any frame
+    # from being still virtuals, because the JIT generates code
+    # to un-virtualizable them "on demand" by loading values based
+    # on FORCE_TOKEN, which is an address in the stack.
+    sthread.ec.force_all_frames()
+
 # ____________________________________________________________
 
 def permute(space, args_w):
diff --git a/pypy/module/_file/test/test_file.py b/pypy/module/_file/test/test_file.py
--- a/pypy/module/_file/test/test_file.py
+++ b/pypy/module/_file/test/test_file.py
@@ -260,8 +260,12 @@
 class AppTestNonblocking(object):
     def setup_class(cls):
         from pypy.module._file.interp_file import W_File
-        
+
         cls.old_read = os.read
+
+        if option.runappdirect:
+            py.test.skip("works with internals of _file impl on py.py")
+
         state = [0]
         def read(fd, n=None):
             if fd != 42:
@@ -281,7 +285,7 @@
 
     def teardown_class(cls):
         os.read = cls.old_read
-        
+
     def test_nonblocking_file(self):
         res = self.stream.read()
         assert res == 'xyz'
@@ -403,24 +407,24 @@
         with self.file(self.temppath, 'w') as f:
             f.write('foo')
         assert f.closed
-        
+
         with self.file(self.temppath, 'r') as f:
             s = f.readline()
 
         assert s == "foo"
         assert f.closed
-    
+
     def test_subclass_with(self):
         file = self.file
         class C(file):
             def __init__(self, *args, **kwargs):
                 self.subclass_closed = False
                 file.__init__(self, *args, **kwargs)
-            
+
             def close(self):
                 self.subclass_closed = True
                 file.close(self)
-        
+
         with C(self.temppath, 'w') as f:
             pass
         assert f.subclass_closed
diff --git a/pypy/module/micronumpy/interp_dtype.py b/pypy/module/micronumpy/interp_dtype.py
--- a/pypy/module/micronumpy/interp_dtype.py
+++ b/pypy/module/micronumpy/interp_dtype.py
@@ -161,9 +161,6 @@
     @binop
     def mul(self, v1, v2):
         return v1 * v2
-    @binop
-    def div(self, v1, v2):
-        return v1 / v2
 
     @unaryop
     def pos(self, v):
@@ -217,6 +214,14 @@
         return float2string(self.for_computation(self.unbox(item)), 'g', rfloat.DTSF_STR_PRECISION)
 
     @binop
+    def div(self, v1, v2):
+        try:
+            return v1 / v2
+        except ZeroDivisionError:
+            if v1 == v2 == 0.0:
+                return rfloat.NAN
+            return rfloat.copysign(rfloat.INFINITY, v1 * v2)
+    @binop
     def mod(self, v1, v2):
         return math.fmod(v1, v2)
     @binop
@@ -295,6 +300,11 @@
         return str(widen(self.unbox(item)))
 
     @binop
+    def div(self, v1, v2):
+        if v2 == 0:
+            return 0
+        return v1 / v2
+    @binop
     def mod(self, v1, v2):
         return v1 % v2
 
@@ -426,23 +436,22 @@
     pass
 
 if LONG_BIT == 32:
-    class W_LongDtype(W_Int32Dtype):
-        pass
+    long_dtype = W_Int32Dtype
+    ulong_dtype = W_UInt32Dtype
+elif LONG_BIT == 64:
+    long_dtype = W_Int64Dtype
+    ulong_dtype = W_UInt64Dtype
+else:
+    assert False
 
-    class W_ULongDtype(W_UInt32Dtype):
-        pass
-else:
-    class W_LongDtype(W_Int64Dtype):
-        pass
+class W_LongDtype(long_dtype):
+    num = 7
+    aliases = ["l"]
+    applevel_types = ["int"]
 
-    class W_ULongDtype(W_UInt64Dtype):
-        pass
-
-W_LongDtype.num = 7
-W_LongDtype.aliases = ["l"]
-W_LongDtype.applevel_types = ["int"]
-W_ULongDtype.num = 8
-W_ULongDtype.aliases = ["L"]
+class W_ULongDtype(ulong_dtype):
+    num = 8
+    aliases = ["L"]
 
 W_Float32Dtype = create_low_level_dtype(
     num = 11, kind = FLOATINGLTR, name = "float32",
diff --git a/pypy/module/micronumpy/test/test_numarray.py b/pypy/module/micronumpy/test/test_numarray.py
--- a/pypy/module/micronumpy/test/test_numarray.py
+++ b/pypy/module/micronumpy/test/test_numarray.py
@@ -285,7 +285,9 @@
             assert b[i] == i * 5
 
     def test_div(self):
-        from numpy import array, dtype
+        from math import isnan
+        from numpy import array, dtype, inf
+
         a = array(range(1, 6))
         b = a / a
         for i in range(5):
@@ -297,6 +299,24 @@
         for i in range(5):
             assert b[i] == 1
 
+        a = array([-1, 0, 1])
+        b = array([0, 0, 0])
+        c = a / b
+        assert (c == [0, 0, 0]).all()
+
+        a = array([-1.0, 0.0, 1.0])
+        b = array([0.0, 0.0, 0.0])
+        c = a / b
+        assert c[0] == -inf
+        assert isnan(c[1])
+        assert c[2] == inf
+
+        b = array([-0.0, -0.0, -0.0])
+        c = a / b
+        assert c[0] == inf
+        assert isnan(c[1])
+        assert c[2] == -inf
+
     def test_div_other(self):
         from numpy import array
         a = array(range(5))
diff --git a/pypy/module/pypyjit/interp_jit.py b/pypy/module/pypyjit/interp_jit.py
--- a/pypy/module/pypyjit/interp_jit.py
+++ b/pypy/module/pypyjit/interp_jit.py
@@ -137,20 +137,15 @@
 
     def jump_absolute(self, jumpto, _, ec=None):
         if we_are_jitted():
-            # Normally, the tick counter is decremented by 100 for every
-            # Python opcode.  Here, to better support JIT compilation of
-            # small loops, we decrement it by a possibly smaller constant.
-            # We get the maximum 100 when the (unoptimized) trace length
-            # is at least 3200 (a bit randomly).
-            trace_length = r_uint(current_trace_length())
-            decr_by = trace_length // 32
-            if decr_by < 1:
-                decr_by = 1
-            elif decr_by > 100:    # also if current_trace_length() returned -1
-                decr_by = 100
+            #
+            # assume that only threads are using the bytecode counter
+            decr_by = 0
+            if self.space.actionflag.has_bytecode_counter:   # constant-folded
+                if self.space.threadlocals.gil_ready:   # quasi-immutable field
+                    decr_by = _get_adapted_tick_counter()
             #
             self.last_instr = intmask(jumpto)
-            ec.bytecode_trace(self, intmask(decr_by))
+            ec.bytecode_trace(self, decr_by)
             jumpto = r_uint(self.last_instr)
         #
         pypyjitdriver.can_enter_jit(frame=self, ec=ec, next_instr=jumpto,
@@ -158,6 +153,20 @@
                                     is_being_profiled=self.is_being_profiled)
         return jumpto
 
+def _get_adapted_tick_counter():
+    # Normally, the tick counter is decremented by 100 for every
+    # Python opcode.  Here, to better support JIT compilation of
+    # small loops, we decrement it by a possibly smaller constant.
+    # We get the maximum 100 when the (unoptimized) trace length
+    # is at least 3200 (a bit randomly).
+    trace_length = r_uint(current_trace_length())
+    decr_by = trace_length // 32
+    if decr_by < 1:
+        decr_by = 1
+    elif decr_by > 100:    # also if current_trace_length() returned -1
+        decr_by = 100
+    return intmask(decr_by)
+
 
 PyCode__initialize = PyCode._initialize
 
diff --git a/pypy/module/pypyjit/test_pypy_c/model.py b/pypy/module/pypyjit/test_pypy_c/model.py
--- a/pypy/module/pypyjit/test_pypy_c/model.py
+++ b/pypy/module/pypyjit/test_pypy_c/model.py
@@ -225,6 +225,8 @@
         # strip comment
         if '#' in line:
             line = line[:line.index('#')]
+        if line.strip() == 'guard_not_invalidated?':
+            return 'guard_not_invalidated', None, [], '...', False
         # find the resvar, if any
         if ' = ' in line:
             resvar, _, line = line.partition(' = ')
@@ -249,7 +251,7 @@
             descr = descr[len('descr='):]
         else:
             descr = None
-        return opname, resvar, args, descr
+        return opname, resvar, args, descr, True
 
     @classmethod
     def preprocess_expected_src(cls, src):
@@ -258,13 +260,23 @@
         # replaced with the corresponding operations, so that tests don't have
         # to repeat it every time
         ticker_check = """
+            guard_not_invalidated?
+            ticker0 = getfield_raw(ticker_address, descr=<SignedFieldDescr pypysig_long_struct.c_value .*>)
+            ticker_cond0 = int_lt(ticker0, 0)
+            guard_false(ticker_cond0, descr=...)
+        """
+        src = src.replace('--TICK--', ticker_check)
+        #
+        # this is the ticker check generated if we have threads
+        thread_ticker_check = """
+            guard_not_invalidated?
             ticker0 = getfield_raw(ticker_address, descr=<SignedFieldDescr pypysig_long_struct.c_value .*>)
             ticker1 = int_sub(ticker0, 1)
             setfield_raw(ticker_address, ticker1, descr=<SignedFieldDescr pypysig_long_struct.c_value .*>)
             ticker_cond0 = int_lt(ticker1, 0)
             guard_false(ticker_cond0, descr=...)
         """
-        src = src.replace('--TICK--', ticker_check)
+        src = src.replace('--THREAD-TICK--', thread_ticker_check)
         #
         # this is the ticker check generated in PyFrame.handle_operation_error
         exc_ticker_check = """
@@ -298,7 +310,7 @@
         if not cond:
             raise InvalidMatch(message, frame=sys._getframe(1))
 
-    def match_op(self, op, (exp_opname, exp_res, exp_args, exp_descr)):
+    def match_op(self, op, (exp_opname, exp_res, exp_args, exp_descr, _)):
         self._assert(op.name == exp_opname, "operation mismatch")
         self.match_var(op.res, exp_res)
         if exp_args != ['...']:
@@ -341,7 +353,7 @@
         what is after the '...'
         """
         iter_exp_ops = iter(expected_ops)
-        iter_ops = iter(self.ops)
+        iter_ops = RevertableIterator(self.ops)
         for opindex, exp_op in enumerate(iter_exp_ops):
             try:
                 if exp_op == '...':
@@ -360,6 +372,9 @@
                             break
                 self.match_op(op, exp_op)
             except InvalidMatch, e:
+                if exp_op[4] is False:    # optional operation
+                    iter_ops.revert_one()
+                    continue       # try to match with the next exp_op
                 e.opindex = opindex
                 raise
         #
@@ -372,8 +387,8 @@
                 return ''
             text = str(py.code.Source(src).deindent().indent())
             lines = text.splitlines(True)
-            if opindex is not None and 0 <= opindex < len(lines):
-                lines[opindex] = lines[opindex].rstrip() + '\t<=====\n'
+            if opindex is not None and 0 <= opindex <= len(lines):
+                lines.insert(opindex, '\n\t===== HERE =====\n')
             return ''.join(lines)
         #
         expected_src = self.preprocess_expected_src(expected_src)
@@ -398,3 +413,18 @@
         else:
             return True
 
+
+class RevertableIterator(object):
+    def __init__(self, sequence):
+        self.sequence = sequence
+        self.index = 0
+    def __iter__(self):
+        return self
+    def next(self):
+        index = self.index
+        if index == len(self.sequence):
+            raise StopIteration
+        self.index = index + 1
+        return self.sequence[index]
+    def revert_one(self):
+        self.index -= 1
diff --git a/pypy/module/pypyjit/test_pypy_c/test_00_model.py b/pypy/module/pypyjit/test_pypy_c/test_00_model.py
--- a/pypy/module/pypyjit/test_pypy_c/test_00_model.py
+++ b/pypy/module/pypyjit/test_pypy_c/test_00_model.py
@@ -145,15 +145,17 @@
 
     def test_parse_op(self):
         res = OpMatcher.parse_op("  a =   int_add(  b,  3 ) # foo")
-        assert res == ("int_add", "a", ["b", "3"], None)
+        assert res == ("int_add", "a", ["b", "3"], None, True)
         res = OpMatcher.parse_op("guard_true(a)")
-        assert res == ("guard_true", None, ["a"], None)
+        assert res == ("guard_true", None, ["a"], None, True)
         res = OpMatcher.parse_op("setfield_gc(p0, i0, descr=<foobar>)")
-        assert res == ("setfield_gc", None, ["p0", "i0"], "<foobar>")
+        assert res == ("setfield_gc", None, ["p0", "i0"], "<foobar>", True)
         res = OpMatcher.parse_op("i1 = getfield_gc(p0, descr=<foobar>)")
-        assert res == ("getfield_gc", "i1", ["p0"], "<foobar>")
+        assert res == ("getfield_gc", "i1", ["p0"], "<foobar>", True)
         res = OpMatcher.parse_op("p0 = force_token()")
-        assert res == ("force_token", "p0", [], None)
+        assert res == ("force_token", "p0", [], None, True)
+        res = OpMatcher.parse_op("guard_not_invalidated?")
+        assert res == ("guard_not_invalidated", None, [], '...', False)
 
     def test_exact_match(self):
         loop = """
@@ -341,7 +343,7 @@
             # this is the actual loop
             'int_lt', 'guard_true', 'int_add',
             # this is the signal checking stuff
-            'getfield_raw', 'int_sub', 'setfield_raw', 'int_lt', 'guard_false',
+            'guard_not_invalidated', 'getfield_raw', 'int_lt', 'guard_false',
             'jump'
             ]
 
@@ -407,7 +409,7 @@
             # this is the actual loop
             'int_lt', 'guard_true', 'force_token', 'int_add',
             # this is the signal checking stuff
-            'getfield_raw', 'int_sub', 'setfield_raw', 'int_lt', 'guard_false',
+            'guard_not_invalidated', 'getfield_raw', 'int_lt', 'guard_false',
             'jump'
             ]
 
@@ -425,10 +427,9 @@
             guard_true(i6, descr=...)
             i8 = int_add(i4, 1)
             # signal checking stuff
+            guard_not_invalidated(descr=...)
             i10 = getfield_raw(37212896, descr=<.* pypysig_long_struct.c_value .*>)
-            i12 = int_sub(i10, 1)
-            setfield_raw(37212896, i12, descr=<.* pypysig_long_struct.c_value .*>)
-            i14 = int_lt(i12, 0)
+            i14 = int_lt(i10, 0)
             guard_false(i14, descr=...)
             jump(p0, p1, p2, p3, i8, descr=...)
         """)
diff --git a/pypy/module/pypyjit/test_pypy_c/test_misc.py b/pypy/module/pypyjit/test_pypy_c/test_misc.py
--- a/pypy/module/pypyjit/test_pypy_c/test_misc.py
+++ b/pypy/module/pypyjit/test_pypy_c/test_misc.py
@@ -329,4 +329,20 @@
             guard_false(i28, descr=...)
             i30 = int_lshift(i20, 24)
             i31 = int_or(i26, i30)
-        """ % {"32_bit_only": extra})
\ No newline at end of file
+        """ % {"32_bit_only": extra})
+
+    def test_eval(self):
+        def main():
+            i = 1
+            a = compile('x+x+x+x+x+x', 'eval', 'eval')
+            b = {'x': 7}
+            while i < 1000:
+                y = eval(a,b,b)  # ID: eval
+                i += 1
+            return y
+
+        log = self.run(main)
+        assert log.result == 42
+        # the following assertion fails if the loop was cancelled due
+        # to "abort: vable escape"
+        assert len(log.loops_by_id("eval")) == 1
diff --git a/pypy/module/pypyjit/test_pypy_c/test_string.py b/pypy/module/pypyjit/test_pypy_c/test_string.py
--- a/pypy/module/pypyjit/test_pypy_c/test_string.py
+++ b/pypy/module/pypyjit/test_pypy_c/test_string.py
@@ -41,7 +41,7 @@
             guard_true(i32, descr=...)
             i34 = int_add(i6, 1)
             --TICK--
-            jump(p0, p1, p2, p3, p4, p5, i34, p7, p8, i9, i10, p11, i12, p13, descr=<Loop4>)
+            jump(p0, p1, p2, p3, p4, p5, i34, p7, p8, i9, i10, p11, i12, p13, descr=...)
         """)
 
     def test_long(self):
@@ -106,7 +106,7 @@
             i58 = int_add_ovf(i6, i57)
             guard_no_overflow(descr=...)
             --TICK--
-            jump(p0, p1, p2, p3, p4, p5, i58, i7, descr=<Loop4>)
+            jump(p0, p1, p2, p3, p4, p5, i58, i7, descr=...)
         """)
 
     def test_str_mod(self):
@@ -156,4 +156,41 @@
             i40 = int_sub(i4, 1)
             --TICK--
             jump(p0, p1, p2, p3, i40, i38, descr=<Loop0>)
-        """)
\ No newline at end of file
+        """)
+
+    def test_getattr_promote(self):
+        def main(n):
+            class A(object):
+                def meth_a(self):
+                    return 1
+                def meth_b(self):
+                    return 2
+            a = A()
+
+            l = ['a', 'b']
+            s = 0
+            for i in range(n):
+                name = 'meth_' + l[i & 1]
+                meth = getattr(a, name) # ID: getattr
+                s += meth()
+            return s
+
+        log = self.run(main, [1000])
+        assert log.result == main(1000)
+        loops = log.loops_by_filename(self.filepath)
+        assert len(loops) == 2
+        for loop in loops:
+            loop.match_by_id('getattr','''
+            guard_not_invalidated(descr=...)
+            i32 = strlen(p31)
+            i34 = int_add(5, i32)
+            p35 = newstr(i34)
+            strsetitem(p35, 0, 109)
+            strsetitem(p35, 1, 101)
+            strsetitem(p35, 2, 116)
+            strsetitem(p35, 3, 104)
+            strsetitem(p35, 4, 95)
+            copystrcontent(p31, p35, 0, 5, i32)
+            i49 = call(ConstClass(_ll_2_str_eq_nonnull__rpy_stringPtr_rpy_stringPtr), p35, ConstPtr(ptr48), descr=<SignedCallDescr>)
+            guard_value(i49, 1, descr=<Guard8>)
+            ''')
diff --git a/pypy/module/pypyjit/test_pypy_c/test_thread.py b/pypy/module/pypyjit/test_pypy_c/test_thread.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/pypyjit/test_pypy_c/test_thread.py
@@ -0,0 +1,28 @@
+from pypy.module.pypyjit.test_pypy_c.test_00_model import BaseTestPyPyC
+
+
+class TestThread(BaseTestPyPyC):
+    def test_simple(self):
+        def main(n):
+            import thread
+            def f():
+                i = 0
+                while i < n:
+                    i += 1
+                done.release()
+
+            done = thread.allocate_lock()
+            done.acquire()
+            thread.start_new_thread(f, ())
+            done.acquire()
+            return 0
+        log = self.run(main, [500])
+        assert round(log.result, 6) == round(main(500), 6)
+        loop, = log.loops_by_filename(self.filepath)
+        assert loop.match("""
+            i2 = int_lt(i0, i1)
+            guard_true(i2, descr=...)
+            i3 = int_add(i0, 1)
+            --THREAD-TICK--
+            jump(..., descr=<Loop0>)
+        """)
diff --git a/pypy/module/signal/interp_signal.py b/pypy/module/signal/interp_signal.py
--- a/pypy/module/signal/interp_signal.py
+++ b/pypy/module/signal/interp_signal.py
@@ -109,8 +109,11 @@
         p = pypysig_getaddr_occurred()
         value = p.c_value
         if self.has_bytecode_counter:    # this 'if' is constant-folded
-            value -= by
-            p.c_value = value
+            if jit.isconstant(by) and by == 0:
+                pass     # normally constant-folded too
+            else:
+                value -= by
+                p.c_value = value
         return value
 
 
diff --git a/pypy/module/sys/__init__.py b/pypy/module/sys/__init__.py
--- a/pypy/module/sys/__init__.py
+++ b/pypy/module/sys/__init__.py
@@ -47,7 +47,7 @@
         'pypy_initial_path'     : 'state.pypy_initial_path',
 
         '_getframe'             : 'vm._getframe', 
-        '_current_frames'       : 'vm._current_frames', 
+        '_current_frames'       : 'currentframes._current_frames', 
         'setrecursionlimit'     : 'vm.setrecursionlimit', 
         'getrecursionlimit'     : 'vm.getrecursionlimit', 
         'setcheckinterval'      : 'vm.setcheckinterval', 
diff --git a/pypy/module/sys/currentframes.py b/pypy/module/sys/currentframes.py
new file mode 100644
--- /dev/null
+++ b/pypy/module/sys/currentframes.py
@@ -0,0 +1,78 @@
+"""
+Implementation of the 'sys._current_frames()' routine.
+"""
+from pypy.interpreter import gateway
+
+app = gateway.applevel('''
+"NOT_RPYTHON"
+import __builtin__
+
+class fake_code(object):
+    co_name = "?"
+    co_filename = "?"
+    co_firstlineno = 0
+
+class fake_frame(object):
+    f_back = None
+    f_builtins = __builtin__.__dict__
+    f_code = fake_code()
+    f_exc_traceback = None
+    f_exc_type = None
+    f_exc_value = None
+    f_globals = {}
+    f_lasti = -1
+    f_lineno = 0
+    f_locals = {}
+    f_restricted = False
+    f_trace = None
+
+    def __init__(self, f):
+        if f is not None:
+            for name in ["f_builtins", "f_code", "f_globals", "f_lasti",
+                         "f_lineno"]:
+                setattr(self, name, getattr(f, name))
+''')
+
+def _current_frames(space):
+    """_current_frames() -> dictionary
+
+    Return a dictionary mapping each current thread T's thread id to T's
+    current stack "frame".  Functions in the traceback module can build the
+    call stack given such a frame.
+
+    Note that in PyPy this returns fake frame objects, to avoid a runtime
+    penalty everywhere with the JIT.  (So far these fake frames can be
+    completely uninformative depending on the JIT state; we could return
+    more with more efforts.)
+
+    This function should be used for specialized purposes only."""
+    w_result = space.newdict()
+    w_fake_frame = app.wget(space, "fake_frame")
+    w_fake_code  = app.wget(space, "fake_code")
+    ecs = space.threadlocals.getallvalues()
+    for thread_ident, ec in ecs.items():
+        vref = ec.topframeref
+        frames = []
+        while not vref.virtual:
+            f = vref()
+            if f is None:
+                break
+            frames.append(f)
+            vref = f.f_backref
+        else:
+            frames.append(None)
+        #
+        w_topframe = space.wrap(None)
+        w_prevframe = None
+        for f in frames:
+            w_nextframe = space.call_function(w_fake_frame, space.wrap(f))
+            if w_prevframe is None:
+                w_topframe = w_nextframe
+            else:
+                space.setattr(w_prevframe, space.wrap('f_back'), w_nextframe)
+            w_prevframe = w_nextframe
+        #
+        space.setitem(w_result,
+                      space.wrap(thread_ident),
+                      w_topframe)
+    return w_result
diff --git a/pypy/module/sys/test/test_sysmodule.py b/pypy/module/sys/test/test_sysmodule.py
--- a/pypy/module/sys/test/test_sysmodule.py
+++ b/pypy/module/sys/test/test_sysmodule.py
@@ -556,7 +556,7 @@
             return sys._current_frames()
         frames = f()
         assert frames.keys() == [0]
-        assert frames[0].f_code.co_name == 'f'
+        assert frames[0].f_code.co_name in ('f', '?')
 
 class AppTestCurrentFramesWithThread(AppTestCurrentFrames):
     def setup_class(cls):
@@ -568,23 +568,25 @@
         import thread
 
         thread_id = thread.get_ident()
-        self.ready = False
         def other_thread():
-            self.ready = True
             print "thread started"
-            time.sleep(5)
+            lock2.release()
+            lock1.acquire()
+        lock1 = thread.allocate_lock()
+        lock2 = thread.allocate_lock()
+        lock1.acquire()
+        lock2.acquire()
         thread.start_new_thread(other_thread, ())
 
         def f():
-            for i in range(100):
-                if self.ready: break
-                time.sleep(0.1)
+            lock2.acquire()
             return sys._current_frames()
 
         frames = f()
+        lock1.release()
         thisframe = frames.pop(thread_id)
-        assert thisframe.f_code.co_name == 'f'
+        assert thisframe.f_code.co_name in ('f', '?')
 
         assert len(frames) == 1
         _, other_frame = frames.popitem()
-        assert other_frame.f_code.co_name == 'other_thread'
+        assert other_frame.f_code.co_name in ('other_thread', '?')
diff --git a/pypy/module/sys/vm.py b/pypy/module/sys/vm.py
--- a/pypy/module/sys/vm.py
+++ b/pypy/module/sys/vm.py
@@ -45,25 +45,6 @@
     f.mark_as_escaped()
     return space.wrap(f)
 
-def _current_frames(space):
-    """_current_frames() -> dictionary
-
-    Return a dictionary mapping each current thread T's thread id to T's
-    current stack frame.
-
-    This function should be used for specialized purposes only."""
-    raise OperationError(space.w_NotImplementedError,
-        space.wrap("XXX sys._current_frames() incompatible with the JIT"))
-    w_result = space.newdict()
-    ecs = space.threadlocals.getallvalues()
-    for thread_ident, ec in ecs.items():
-        f = ec.gettopframe_nohidden()
-        f.mark_as_escaped()
-        space.setitem(w_result,
-                      space.wrap(thread_ident),
-                      space.wrap(f))
-    return w_result
-
 def setrecursionlimit(space, w_new_limit):
     """setrecursionlimit() sets the maximum number of nested calls that
 can occur before a RuntimeError is raised.  On PyPy the limit is
diff --git a/pypy/module/thread/gil.py b/pypy/module/thread/gil.py
--- a/pypy/module/thread/gil.py
+++ b/pypy/module/thread/gil.py
@@ -17,6 +17,7 @@
 class GILThreadLocals(OSThreadLocals):
     """A version of OSThreadLocals that enforces a GIL."""
     gil_ready = False
+    _immutable_fields_ = ['gil_ready?']
 
     def initialize(self, space):
         # add the GIL-releasing callback as an action on the space
diff --git a/pypy/module/thread/threadlocals.py b/pypy/module/thread/threadlocals.py
--- a/pypy/module/thread/threadlocals.py
+++ b/pypy/module/thread/threadlocals.py
@@ -8,9 +8,14 @@
 
     def __init__(self):
         self._valuedict = {}   # {thread_ident: ExecutionContext()}
+        self._freeze_()
+
+    def _freeze_(self):
+        self._valuedict.clear()
         self._mainthreadident = 0
         self._mostrecentkey = 0        # fast minicaching for the common case
         self._mostrecentvalue = None   # fast minicaching for the common case
+        return False
 
     def getvalue(self):
         ident = thread.get_ident()
diff --git a/pypy/objspace/std/objecttype.py b/pypy/objspace/std/objecttype.py
--- a/pypy/objspace/std/objecttype.py
+++ b/pypy/objspace/std/objecttype.py
@@ -44,7 +44,6 @@
         raise OperationError(space.w_TypeError,
                              space.wrap("__class__ assignment: only for heap types"))
     w_oldcls = space.type(w_obj)
-    # XXX taint space should raise a TaintError here if w_oldcls is tainted
     assert isinstance(w_oldcls, W_TypeObject)
     if w_oldcls.get_full_instance_layout() == w_newcls.get_full_instance_layout():
         w_obj.setclass(space, w_newcls)
diff --git a/pypy/objspace/std/stringobject.py b/pypy/objspace/std/stringobject.py
--- a/pypy/objspace/std/stringobject.py
+++ b/pypy/objspace/std/stringobject.py
@@ -161,19 +161,19 @@
 
 def str_swapcase__String(space, w_self):
     self = w_self._value
-    res = [' '] * len(self)
+    builder = StringBuilder(len(self))
     for i in range(len(self)):
         ch = self[i]
         if ch.isupper():
             o = ord(ch) + 32
-            res[i] = chr(o)
+            builder.append(chr(o))
         elif ch.islower():
             o = ord(ch) - 32
-            res[i] = chr(o)
+            builder.append(chr(o))
         else:
-            res[i] = ch
+            builder.append(ch)
 
-    return space.wrap("".join(res))
+    return space.wrap(builder.build())
 
 
 def str_capitalize__String(space, w_self):
@@ -199,19 +199,21 @@
 
 def str_title__String(space, w_self):
     input = w_self._value
-    buffer = [' '] * len(input)
+    builder = StringBuilder(len(input))
     prev_letter=' '
 
-    for pos in range(0, len(input)):
+    for pos in range(len(input)):
         ch = input[pos]
         if not prev_letter.isalpha():
-            buffer[pos] = _upper(ch)
+            ch = _upper(ch)
+            builder.append(ch)
         else:
-            buffer[pos] = _lower(ch)
+            ch = _lower(ch)
+            builder.append(ch)
 
-        prev_letter = buffer[pos]
+        prev_letter = ch
 
-    return space.wrap("".join(buffer))
+    return space.wrap(builder.build())
 
 def str_split__String_None_ANY(space, w_self, w_none, w_maxsplit=-1):
     maxsplit = space.int_w(w_maxsplit)
@@ -754,27 +756,21 @@
     input = w_self._value
     width = space.int_w(w_width)
 
-    if len(input) >= width:
+    num_zeros = width - len(input)
+    if num_zeros <= 0:
         # cannot return w_self, in case it is a subclass of str
         return space.wrap(input)
 
-    buf = [' '] * width
+    builder = StringBuilder(width)
     if len(input) > 0 and (input[0] == '+' or input[0] == '-'):
-        buf[0] = input[0]
+        builder.append(input[0])
         start = 1
-        middle = width - len(input) + 1
     else:
         start = 0
-        middle = width - len(input)
 
-    for i in range(start, middle):
-        buf[i] = '0'
-
-    for i in range(middle, width):
-        buf[i] = input[start]
-        start = start + 1
-
-    return space.wrap("".join(buf))
+    builder.append_multiple_char('0', num_zeros)
+    builder.append_slice(input, start, len(input))
+    return space.wrap(builder.build())
 
 
 def hash__String(space, w_str):
diff --git a/pypy/objspace/std/typeobject.py b/pypy/objspace/std/typeobject.py
--- a/pypy/objspace/std/typeobject.py
+++ b/pypy/objspace/std/typeobject.py
@@ -10,7 +10,8 @@
 from pypy.objspace.std import identitydict
 from pypy.rlib.objectmodel import we_are_translated
 from pypy.rlib.objectmodel import current_object_addr_as_int, compute_hash
-from pypy.rlib.jit import promote, elidable_promote, we_are_jitted
+from pypy.rlib.jit import promote, elidable_promote, we_are_jitted,\
+     promote_string
 from pypy.rlib.jit import elidable, dont_look_inside, unroll_safe
 from pypy.rlib.rarithmetic import intmask, r_uint
 
@@ -101,6 +102,7 @@
                           'instancetypedef',
                           'terminator',
                           '_version_tag?',
+                          'interplevel_cls',
                           ]
 
     # for config.objspace.std.getattributeshortcut
@@ -399,6 +401,7 @@
         if version_tag is None:
             tup = w_self._lookup_where(name)
             return tup
+        name = promote_string(name)
         w_class, w_value = w_self._pure_lookup_where_with_method_cache(name, version_tag)
         return w_class, unwrap_cell(space, w_value)
 
diff --git a/pypy/objspace/std/unicodeobject.py b/pypy/objspace/std/unicodeobject.py
--- a/pypy/objspace/std/unicodeobject.py
+++ b/pypy/objspace/std/unicodeobject.py
@@ -317,54 +317,54 @@
     input = w_self._value
     if len(input) == 0:
         return W_UnicodeObject.EMPTY
-    result = [u'\0'] * len(input)
-    result[0] = unichr(unicodedb.toupper(ord(input[0])))
+    builder = UnicodeBuilder(len(input))
+    builder.append(unichr(unicodedb.toupper(ord(input[0]))))
     for i in range(1, len(input)):
-        result[i] = unichr(unicodedb.tolower(ord(input[i])))
-    return W_UnicodeObject(u''.join(result))
+        builder.append(unichr(unicodedb.tolower(ord(input[i]))))
+    return W_UnicodeObject(builder.build())
 
 def unicode_title__Unicode(space, w_self):
     input = w_self._value
     if len(input) == 0:
         return w_self
-    result = [u'\0'] * len(input)
+    builder = UnicodeBuilder(len(input))
 
     previous_is_cased = False
     for i in range(len(input)):
         unichar = ord(input[i])
         if previous_is_cased:
-            result[i] = unichr(unicodedb.tolower(unichar))
+            builder.append(unichr(unicodedb.tolower(unichar)))
         else:
-            result[i] = unichr(unicodedb.totitle(unichar))
+            builder.append(unichr(unicodedb.totitle(unichar)))
         previous_is_cased = unicodedb.iscased(unichar)
-    return W_UnicodeObject(u''.join(result))
+    return W_UnicodeObject(builder.build())
 
 def unicode_lower__Unicode(space, w_self):
     input = w_self._value
-    result = [u'\0'] * len(input)
+    builder = UnicodeBuilder(len(input))
     for i in range(len(input)):
-        result[i] = unichr(unicodedb.tolower(ord(input[i])))
-    return W_UnicodeObject(u''.join(result))
+        builder.append(unichr(unicodedb.tolower(ord(input[i]))))
+    return W_UnicodeObject(builder.build())
 
 def unicode_upper__Unicode(space, w_self):
     input = w_self._value
-    result = [u'\0'] * len(input)
+    builder = UnicodeBuilder(len(input))
     for i in range(len(input)):
-        result[i] = unichr(unicodedb.toupper(ord(input[i])))
-    return W_UnicodeObject(u''.join(result))
+        builder.append(unichr(unicodedb.toupper(ord(input[i]))))
+    return W_UnicodeObject(builder.build())
 
 def unicode_swapcase__Unicode(space, w_self):
     input = w_self._value
-    result = [u'\0'] * len(input)
+    builder = UnicodeBuilder(len(input))
     for i in range(len(input)):
         unichar = ord(input[i])
         if unicodedb.islower(unichar):
-            result[i] = unichr(unicodedb.toupper(unichar))
+            builder.append(unichr(unicodedb.toupper(unichar)))
         elif unicodedb.isupper(unichar):
-            result[i] = unichr(unicodedb.tolower(unichar))
+            builder.append(unichr(unicodedb.tolower(unichar)))
         else:
-            result[i] = input[i]
-    return W_UnicodeObject(u''.join(result))
+            builder.append(input[i])
+    return W_UnicodeObject(builder.build())
 
 def _normalize_index(length, index):
     if index < 0:
diff --git a/pypy/objspace/taint.py b/pypy/objspace/taint.py
deleted file mode 100644
--- a/pypy/objspace/taint.py
+++ /dev/null
@@ -1,294 +0,0 @@
-"""
-Just an experiment.
-"""
-import os
-from pypy.objspace.std.objspace import StdObjSpace
-from pypy.objspace.proxy import patch_space_in_place
-from pypy.objspace.thunk import nb_forcing_args
-from pypy.interpreter.error import OperationError
-from pypy.interpreter import baseobjspace, gateway, executioncontext
-from pypy.interpreter.function import Method
-from pypy.interpreter.pyframe import PyFrame
-from pypy.tool.sourcetools import func_with_new_name
-from pypy.rlib.unroll import unrolling_iterable
-
-
-class W_Tainted(baseobjspace.W_Root):
-    def __init__(self, w_obj):
-        self.w_obj = w_obj
-
-##    def getdict(self, space):
-##        return taint(self.w_obj.getdict(space))
-
-##    def getdictvalue(self, space, attr):
-##        return taint(self.w_obj.getdictvalue(space, attr))
-
-##    def setdictvalue(self, space, attr, w_value):
-##        return self.w_obj.setdictvalue(space, attr, w_value)
-
-##    ...
-
-class W_TaintBomb(baseobjspace.W_Root):
-    filename = '?'
-    codename = '?'
-    codeline = 0
-
-    def __init__(self, space, operr):
-        self.space = space
-        self.operr = operr
-        self.record_debug_info()
-
-    def record_debug_info(self):
-        ec = self.space.getexecutioncontext()
-        frame = ec.gettopframe_nohidden()
-        if isinstance(frame, PyFrame):     # and, in particular, frame != None
-            self.filename = frame.pycode.co_filename
-            self.codename = frame.pycode.co_name
-            self.codeline = frame.get_last_lineno()
-        if get_debug_level(self.space) > 0:
-            self.debug_dump()
-
-    def debug_dump(self):
-        os.write(2, 'Taint Bomb from file "%s", line %d, in %s\n    %s\n' % (
-            self.filename, self.codeline, self.codename,
-            self.operr.errorstr(self.space)))
-
-    def explode(self):
-        #msg = self.operr.errorstr(space)
-        raise OperationError(self.space.w_TaintError, self.space.w_None)
-
-
-def taint(w_obj):
-    """Return a tainted version of the argument."""
-    if w_obj is None or isinstance(w_obj, W_Tainted):
-        return w_obj
-    else:
-        return W_Tainted(w_obj)
-app_taint = gateway.interp2app(taint)
-
-def is_tainted(space, w_obj):
-    """Return whether the argument is tainted."""
-    res = isinstance(w_obj, W_Tainted) or isinstance(w_obj, W_TaintBomb)
-    return space.wrap(res)
-app_is_tainted = gateway.interp2app(is_tainted)
-
-def untaint(space, w_expectedtype, w_obj):
-    """untaint(expectedtype, tainted_obj) -> obj
-Untaint untainted_obj and return it. If the result is not of expectedtype,
-raise a type error."""
-    if (isinstance(w_expectedtype, W_Tainted) or
-        isinstance(w_expectedtype, W_TaintBomb)):
-        raise OperationError(space.w_TypeError,
-                  space.wrap("untaint() arg 1 must be an untainted type"))
-    if not space.is_true(space.isinstance(w_expectedtype, space.w_type)):
-        raise OperationError(space.w_TypeError,
-                             space.wrap("untaint() arg 1 must be a type"))
-    if isinstance(w_obj, W_Tainted):
-        w_obj = w_obj.w_obj
-    elif isinstance(w_obj, W_TaintBomb):
-        w_obj.explode()
-    #if isinstance(w_expectedtype, W_Tainted):
-    #    w_expectedtype = w_expectedtype.w_obj
-    w_realtype = space.type(w_obj)
-    if not space.is_w(w_realtype, w_expectedtype):
-        #msg = "expected an object of type '%s'" % (
-        #    w_expectedtype.getname(space),)
-        #    #w_realtype.getname(space))
-        raise OperationError(space.w_TaintError, space.w_None)
-    return w_obj
-app_untaint = gateway.interp2app(untaint)
-
-# ____________________________________________________________
-
- at gateway.unwrap_spec(args_w='args_w')
-def taint_atomic_function(space, w_func, args_w):
-    newargs_w = []
-    tainted = False
-    for w_arg in args_w:
-        if isinstance(w_arg, W_Tainted):
-            tainted = True
-            w_arg = w_arg.w_obj
-        elif isinstance(w_arg, W_TaintBomb):
-            return w_arg
-        newargs_w.append(w_arg)
-    w_newargs = space.newtuple(newargs_w)
-    try:
-        w_res = space.call(w_func, w_newargs)
-    except OperationError, operr:
-        if not tainted:
-            raise
-        return W_TaintBomb(space, operr)
-    if tainted:
-        w_res = taint(w_res)
-    return w_res
-
-app_taint_atomic_function = gateway.interp2app(taint_atomic_function)
-
-def taint_atomic(space, w_callable):
-    """decorator to make a callable "taint-atomic": if the function is called
-with tainted arguments, those are untainted. The result of the function is
-tainted again.  All exceptions that the callable raises are turned into
-taint bombs."""
-    meth = Method(space, space.w_fn_taint_atomic_function,
-                  w_callable, space.type(w_callable))
-    return space.wrap(meth)
-app_taint_atomic = gateway.interp2app(taint_atomic)
-
-# ____________________________________________________________
-
-executioncontext.ExecutionContext.taint_debug = 0
-
- at gateway.unwrap_spec(level=int)
-def taint_debug(space, level):
-    """Set the debug level. If the debug level is greater than 0, the creation
-of taint bombs will print debug information. For debugging purposes
-only!"""
-    space.getexecutioncontext().taint_debug = level
-app_taint_debug = gateway.interp2app(taint_debug)
-
-def taint_look(space, w_obj):
-    """Print some info about the taintedness of an object. For debugging
-purposes only!"""
-    if isinstance(w_obj, W_Tainted):
-        info = space.type(w_obj.w_obj).getname(space)
-        msg = space.str_w(w_obj.w_obj.getrepr(space, info))
-        msg = 'Taint Box %s\n' % msg
-        os.write(2, msg)
-    elif isinstance(w_obj, W_TaintBomb):
-        w_obj.debug_dump()
-    else:
-        os.write(2, 'not tainted\n')
-app_taint_look = gateway.interp2app(taint_look)
-
-def get_debug_level(space):
-    return space.getexecutioncontext().taint_debug
-
-def debug_bomb(space, operr):
-    ec = space.getexecutioncontext()
-    filename = '?'
-    codename = '?'
-    codeline = 0
-    frame = ec.gettopframe_nohidden()
-    if isinstance(frame, PyFrame):     # and, in particular, frame != None
-        filename = frame.pycode.co_filename
-        codename = frame.pycode.co_name
-        codeline = frame.get_last_lineno()
-    os.write(2, 'Taint Bomb in file "%s", line %d, in %s\n    %s\n' % (
-        filename, codeline, codename, operr.errorstr(space)))
-
-# ____________________________________________________________
-
-
-class TaintSpace(StdObjSpace):
-
-    def __init__(self, *args, **kwds):
-        StdObjSpace.__init__(self, *args, **kwds)
-        w_dict = self.newdict()
-        self.setitem(w_dict, self.wrap("__doc__"), self.wrap("""\
-Exception that is raised when an operation revealing information on a tainted
-object is performed."""))
-        self.w_TaintError = self.call_function(
-            self.w_type,
-            self.wrap("TaintError"),
-            self.newtuple([self.w_Exception]),
-            w_dict
-            )
-        w___pypy__ = self.getbuiltinmodule("__pypy__")
-        self.setattr(w___pypy__, self.wrap('taint'),
-                     self.wrap(app_taint))
-        self.setattr(w___pypy__, self.wrap('is_tainted'),
-                     self.wrap(app_is_tainted))
-        self.setattr(w___pypy__, self.wrap('untaint'),
-                     self.wrap(app_untaint))
-        self.w_fn_taint_atomic_function = self.wrap(app_taint_atomic_function)
-        self.setattr(w___pypy__, self.wrap('taint_atomic'),
-                     self.wrap(app_taint_atomic))
-        self.setattr(w___pypy__, self.wrap('TaintError'),
-                     self.w_TaintError)
-        self.setattr(w___pypy__, self.wrap('_taint_debug'),
-                     self.wrap(app_taint_debug))
-        self.setattr(w___pypy__, self.wrap('_taint_look'),
-                     self.wrap(app_taint_look))
-        patch_space_in_place(self, 'taint', proxymaker)
-
-        # XXX may leak info, perfomance hit, what about taint bombs?
-        from pypy.objspace.std.typeobject import W_TypeObject
-
-        def taint_lookup(w_obj, name):
-            if isinstance(w_obj, W_Tainted):
-                w_obj = w_obj.w_obj
-            w_type = self.type(w_obj)
-            assert isinstance(w_type, W_TypeObject)
-            return w_type.lookup(name)
-
-        def taint_lookup_in_type_where(w_obj, name):
-            if isinstance(w_obj, W_Tainted):
-                w_type = w_obj.w_obj
-            else:
-                w_type = w_obj
-            assert isinstance(w_type, W_TypeObject)
-            return w_type.lookup_where(name)
-
-        self.lookup = taint_lookup
-        self.lookup_in_type_where = taint_lookup_in_type_where
-
-
-Space = TaintSpace
-
-
-def tainted_error(space, name):
-    #msg = "operation '%s' forbidden on tainted object" % (name,)
-    raise OperationError(space.w_TaintError, space.w_None)# space.wrap(msg))
-
-
-RegularMethods = dict.fromkeys(
-    [name for name, _, _, _ in baseobjspace.ObjSpace.MethodTable])
-
-TaintResultIrregularMethods = dict.fromkeys(
-    ['wrap', 'call_args'] +
-    [name for name in baseobjspace.ObjSpace.IrregularOpTable
-          if name.startswith('new')])
-
-def proxymaker(space, name, parentfn):
-    arity = nb_forcing_args[name]
-    indices = unrolling_iterable(range(arity))
-    if name in RegularMethods:
-
-        def proxy(*args_w):
-            newargs_w = ()
-            tainted = False
-            for i in indices:
-                w_arg = args_w[i]
-                if isinstance(w_arg, W_Tainted):
-                    tainted = True
-                    w_arg = w_arg.w_obj
-                elif isinstance(w_arg, W_TaintBomb):
-                    return w_arg
-                newargs_w += (w_arg,)
-            newargs_w += args_w[arity:]
-            try:
-                w_res = parentfn(*newargs_w)
-            except OperationError, operr:
-                if not tainted:
-                    raise
-                return W_TaintBomb(space, operr)
-            if tainted:
-                w_res = taint(w_res)
-            return w_res
-
-    elif arity == 0:
-        return None
-
-    else:
-
-        def proxy(*args_w):
-            for i in indices:
-                w_arg = args_w[i]
-                if isinstance(w_arg, W_Tainted):
-                    tainted_error(space, name)
-                elif isinstance(w_arg, W_TaintBomb):
-                    w_arg.explode()
-            return parentfn(*args_w)
-
-    proxy = func_with_new_name(proxy, '%s_proxy' % name)
-    return proxy
diff --git a/pypy/objspace/test/test_taintobjspace.py b/pypy/objspace/test/test_taintobjspace.py
deleted file mode 100644
--- a/pypy/objspace/test/test_taintobjspace.py
+++ /dev/null
@@ -1,77 +0,0 @@
-from pypy.conftest import gettestobjspace
-
-class AppTest_Taint:
-
-    def setup_class(cls):
-        cls.space = gettestobjspace('taint')
-
-    def test_simple(self):
-        from __pypy__ import taint, untaint, TaintError
-        x = taint(6)
-        x = x * 7
-        raises(TaintError, "if x: y = 1")
-        t = type(x)
-        raises(TaintError, "if t is int: y = 1")
-        assert untaint(int, x) == 42
-        raises(TaintError, "untaint(float, x)")
-
-    def test_bomb(self):
-        from __pypy__ import taint, untaint, TaintError
-        x = taint(6)
-        x = x / 0
-        raises(TaintError, "if x: y = 1")
-        t = type(x)
-        raises(TaintError, "if t is int: y = 1")
-        raises(TaintError, "untaint(int, x)")
-        raises(TaintError, "untaint(float, x)")
-
-    def test_taint_atomic(self):
-        from __pypy__ import taint, untaint, TaintError, taint_atomic
-        x = taint(6)
-        x *= 7
-
-        def dummy(x):
-            if x > 40:
-                return 5
-            else:
-                return 3
-        dummy = taint_atomic(dummy)
-
-        y = dummy(x)
-        raises(TaintError, "if y == 3: z = 1")
-        assert untaint(int, y) == 5
-
-    def test_taint_atomic_exception(self):
-        from __pypy__ import taint, untaint, TaintError, taint_atomic
-        x = taint(6)
-        x *= 7
-
-        def dummy(x):
-            if x + "world" == "hello world":
-                return 5
-            else:
-                return 3
-        dummy = taint_atomic(dummy)
-
-        y = dummy(x)
-        raises(TaintError, "if y == 3: z = 1")
-        raises(TaintError, "untaint(int, y)")
-
-    def test_taint_atomic_incoming_bomb(self):
-        from __pypy__ import taint, untaint, TaintError, taint_atomic
-        x = taint(6)
-        x /= 0
-        lst = []
-
-        def dummy(x):
-            lst.append("running!")
-            if x > 40:
-                return 5
-            else:
-                return 3
-        dummy = taint_atomic(dummy)
-
-        y = dummy(x)
-        raises(TaintError, "if y == 3: z = 1")
-        assert lst == []
-        raises(TaintError, "untaint(int, y)")
diff --git a/pypy/rlib/_jit_vref.py b/pypy/rlib/_jit_vref.py
--- a/pypy/rlib/_jit_vref.py
+++ b/pypy/rlib/_jit_vref.py
@@ -25,6 +25,10 @@
     def simple_call(self):
         return self.s_instance
 
+    def getattr(self, s_attr):
+        assert s_attr.const == 'virtual'
+        return annmodel.s_Bool
+
     def rtyper_makerepr(self, rtyper):
         if rtyper.type_system.name == 'lltypesystem':
             return vrefrepr
@@ -61,6 +65,13 @@
                              " prebuilt virtual_ref")
         return lltype.nullptr(OBJECTPTR.TO)
 
+    def rtype_getattr(self, hop):
+        s_attr = hop.args_s[1]
+        assert s_attr.const == 'virtual'
+        v = hop.inputarg(self, arg=0)
+        hop.exception_cannot_occur()
+        return hop.genop('jit_is_virtual', [v], resulttype = lltype.Bool)
+
 from pypy.rpython.ootypesystem.rclass import OBJECT
 
 class OOVRefRepr(VRefRepr):
diff --git a/pypy/rlib/jit.py b/pypy/rlib/jit.py
--- a/pypy/rlib/jit.py
+++ b/pypy/rlib/jit.py
@@ -38,6 +38,7 @@
     possible arguments are:
 
     * promote - promote the argument from a variable into a constant
+    * promote_string - same, but promote string by *value*
     * access_directly - directly access a virtualizable, as a structure
                         and don't treat it as a virtualizable
     * fresh_virtualizable - means that virtualizable was just allocated.
@@ -51,6 +52,9 @@
 def promote(x):
     return hint(x, promote=True)
 
+def promote_string(x):
+    return hint(x, promote_string=True)
+
 def dont_look_inside(func):
     """ Make sure the JIT does not trace inside decorated function
     (it becomes a call instead)
@@ -313,6 +317,12 @@
             raise InvalidVirtualRef
         return self._x
 
+    @property
+    def virtual(self):
+        """A property that is True if the vref contains a virtual that would
+        be forced by the '()' operator."""
+        return self._state == 'non-forced'
+
     def _finish(self):
         if self._state == 'non-forced':
             self._state = 'invalid'
diff --git a/pypy/rlib/rerased.py b/pypy/rlib/rerased.py
--- a/pypy/rlib/rerased.py
+++ b/pypy/rlib/rerased.py
@@ -218,15 +218,13 @@
         [v_value] = hop.inputargs(lltype.Signed)
         c_one = hop.inputconst(lltype.Signed, 1)
         hop.exception_is_here()
-        v2 = hop.genop('int_lshift_ovf', [v_value, c_one],
+        v2 = hop.genop('int_add_ovf', [v_value, v_value],
                        resulttype = lltype.Signed)
         v2p1 = hop.genop('int_add', [v2, c_one],
                          resulttype = lltype.Signed)
         v_instance = hop.genop('cast_int_to_ptr', [v2p1],
                                resulttype=self.lowleveltype)
-        v = hop.genop('cast_opaque_ptr', [v_instance],
-                      resulttype=self.lowleveltype)
-        return v
+        return v_instance
 
     def convert_const(self, value):
         if value._identity is _identity_for_ints:
@@ -266,10 +264,10 @@
         return hop.genop('int_rshift', [v2, c_one], resulttype=lltype.Signed)
 
     def rtype_erase_int(self, hop):
-        hop.exception_is_here()
         [v_value] = hop.inputargs(lltype.Signed)
         c_one = hop.inputconst(lltype.Signed, 1)
-        v2 = hop.genop('int_lshift_ovf', [v_value, c_one],
+        hop.exception_is_here()
+        v2 = hop.genop('int_add_ovf', [v_value, v_value],
                        resulttype = lltype.Signed)
         v2p1 = hop.genop('int_add', [v2, c_one],
                          resulttype = lltype.Signed)
diff --git a/pypy/rlib/test/test__jit_vref.py b/pypy/rlib/test/test__jit_vref.py
--- a/pypy/rlib/test/test__jit_vref.py
+++ b/pypy/rlib/test/test__jit_vref.py
@@ -27,10 +27,13 @@
     x1 = X()
     vref = virtual_ref(x1)
     assert vref._state == 'non-forced'
+    assert vref.virtual is True
     assert vref() is x1
     assert vref._state == 'forced'
+    assert vref.virtual is False
     virtual_ref_finish(vref, x1)
     assert vref._state == 'forced'
+    assert vref.virtual is False
     assert vref() is x1
 
 def test_direct_invalid():
@@ -135,6 +138,13 @@
         x = self.interpret(f, [])
         assert x == 42
 
+    def test_rtype_virtualattr(self):
+        def f():
+            vref = virtual_ref(X())
+            return vref.virtual
+        x = self.interpret(f, [])
+        assert x is False
+
 
 class TestLLtype(BaseTestVRef, LLRtypeMixin):
     OBJECTTYPE = OBJECTPTR
diff --git a/pypy/rlib/test/test_jit.py b/pypy/rlib/test/test_jit.py
--- a/pypy/rlib/test/test_jit.py
+++ b/pypy/rlib/test/test_jit.py
@@ -139,12 +139,11 @@
 
     def test_isconstant(self):
         def f(n):
-            assert n >= 0
             assert isconstant(n) is False
             l = []
             l.append(n)
             return len(l)
-        res = self.interpret(f, [234])
+        res = self.interpret(f, [-234])
         assert res == 1
 
 
diff --git a/pypy/rpython/lltypesystem/ll2ctypes.py b/pypy/rpython/lltypesystem/ll2ctypes.py
--- a/pypy/rpython/lltypesystem/ll2ctypes.py
+++ b/pypy/rpython/lltypesystem/ll2ctypes.py
@@ -658,6 +658,8 @@
         if T == llmemory.GCREF:
             if isinstance(llobj._obj, _llgcopaque):
                 return ctypes.c_void_p(llobj._obj.intval)
+            if isinstance(llobj._obj, int):    # tagged pointer
+                return ctypes.c_void_p(llobj._obj)
             container = llobj._obj.container
             T = lltype.Ptr(lltype.typeOf(container))
             # otherwise it came from integer and we want a c_void_p with
@@ -1268,6 +1270,7 @@
 class _llgcopaque(lltype._container):
     _TYPE = llmemory.GCREF.TO
     _name = "_llgcopaque"
+    _read_directly_intval = True     # for _ptr._cast_to_int()
 
     def __init__(self, void_p):
         if isinstance(void_p, (int, long)):
@@ -1299,11 +1302,6 @@
             return _opaque_objs[self.intval // 2]
         return force_cast(PTRTYPE, self.intval)
 
-##     def _cast_to_int(self):
-##         return self.intval
-
-##     def _cast_to_adr(self):
-##         return _lladdress(self.intval)
 
 def cast_adr_to_int(addr):
     if isinstance(addr, llmemory.fakeaddress):
diff --git a/pypy/rpython/lltypesystem/llmemory.py b/pypy/rpython/lltypesystem/llmemory.py
--- a/pypy/rpython/lltypesystem/llmemory.py
+++ b/pypy/rpython/lltypesystem/llmemory.py
@@ -498,6 +498,8 @@
 
     def _cast_to_int(self, symbolic=False):
         if self:
+            if isinstance(self.ptr._obj0, int):    # tagged integer
+                return self.ptr._obj0
             if symbolic:
                 return AddressAsInt(self)
             else:
diff --git a/pypy/rpython/lltypesystem/lloperation.py b/pypy/rpython/lltypesystem/lloperation.py
--- a/pypy/rpython/lltypesystem/lloperation.py
+++ b/pypy/rpython/lltypesystem/lloperation.py
@@ -428,6 +428,7 @@
     'jit_marker':           LLOp(),
     'jit_force_virtualizable':LLOp(canrun=True),
     'jit_force_virtual':    LLOp(canrun=True),
+    'jit_is_virtual':       LLOp(canrun=True),
     'jit_force_quasi_immutable': LLOp(canrun=True),
     'get_exception_addr':   LLOp(),
     'get_exc_value_addr':   LLOp(),
diff --git a/pypy/rpython/lltypesystem/lltype.py b/pypy/rpython/lltypesystem/lltype.py
--- a/pypy/rpython/lltypesystem/lltype.py
+++ b/pypy/rpython/lltypesystem/lltype.py
@@ -1360,6 +1360,8 @@
         obj = normalizeptr(self, check)._getobj(check)
         if isinstance(obj, int):
             return obj     # special case for cast_int_to_ptr() results put into opaques
+        if getattr(obj, '_read_directly_intval', False):
+            return obj.intval   # special case for _llgcopaque
         result = intmask(obj._getid())
         # assume that id() returns an addressish value which is
         # not zero and aligned to at least a multiple of 4
diff --git a/pypy/rpython/lltypesystem/opimpl.py b/pypy/rpython/lltypesystem/opimpl.py
--- a/pypy/rpython/lltypesystem/opimpl.py
+++ b/pypy/rpython/lltypesystem/opimpl.py
@@ -538,6 +538,9 @@
 def op_jit_force_virtual(x):
     return x
 
+def op_jit_is_virtual(x):
+    return False
+
 def op_jit_force_quasi_immutable(*args):
     pass
 
diff --git a/pypy/rpython/lltypesystem/rtagged.py b/pypy/rpython/lltypesystem/rtagged.py
--- a/pypy/rpython/lltypesystem/rtagged.py
+++ b/pypy/rpython/lltypesystem/rtagged.py
@@ -43,7 +43,7 @@
         v_value = hop.inputarg(lltype.Signed, arg=1)
         c_one = hop.inputconst(lltype.Signed, 1)
         hop.exception_is_here()
-        v2 = hop.genop('int_lshift_ovf', [v_value, c_one],
+        v2 = hop.genop('int_add_ovf', [v_value, v_value],
                        resulttype = lltype.Signed)
         v2p1 = hop.genop('int_add', [v2, c_one],
                          resulttype = lltype.Signed)
diff --git a/pypy/rpython/lltypesystem/test/test_ll2ctypes.py b/pypy/rpython/lltypesystem/test/test_ll2ctypes.py
--- a/pypy/rpython/lltypesystem/test/test_ll2ctypes.py
+++ b/pypy/rpython/lltypesystem/test/test_ll2ctypes.py
@@ -1123,6 +1123,9 @@
 
         #assert lltype.cast_ptr_to_int(ref1) == intval
 
+        x = rffi.cast(llmemory.GCREF, -17)
+        assert lltype.cast_ptr_to_int(x) == -17
+
     def test_ptr_truth(self):
         abc = rffi.cast(lltype.Ptr(lltype.FuncType([], lltype.Void)), 0)
         assert not abc
diff --git a/pypy/rpython/rclass.py b/pypy/rpython/rclass.py
--- a/pypy/rpython/rclass.py
+++ b/pypy/rpython/rclass.py
@@ -191,6 +191,10 @@
                     "class %r inherits from its parent _immutable_=True, "
                     "so it should also declare _immutable_=True" % (
                     self.classdef,))
+            if loc.classdict.get('_immutable_').value is not True:
+                raise TyperError(
+                    "class %r: _immutable_ = something else than True" % (
+                    self.classdef,))
             hints = hints.copy()
             hints['immutable'] = True
         self.immutable_field_set = set()  # unless overwritten below
diff --git a/pypy/tool/logparser.py b/pypy/tool/logparser.py
--- a/pypy/tool/logparser.py
+++ b/pypy/tool/logparser.py
@@ -298,6 +298,8 @@
         image.paste(textpercent, (t1x, 5), textpercent)
         image.paste(textlabel,   (t2x, 5), textlabel)
         images.append(image)
+    if not images:
+        return None
     return combine(images, spacing=0, border=1, horizontal=False)
 
 def get_timesummary_single_image(totaltimes, totaltime0, componentdict,
@@ -333,6 +335,8 @@
         del totaltimes[None]
     img2 = render_histogram(totaltimes, totaltime0, {},
                             width, summarybarheight)
+    if img2 is None:
+        return img1
     return combine([img1, img2], spacing=spacing, horizontal=True)
 
 # ----------
diff --git a/pypy/translator/c/funcgen.py b/pypy/translator/c/funcgen.py
--- a/pypy/translator/c/funcgen.py
+++ b/pypy/translator/c/funcgen.py
@@ -833,7 +833,7 @@
         return 'INSTRUMENT_COUNT(%s);' % counter_label
             
     def OP_IS_EARLY_CONSTANT(self, op):
-        return self.expr(op.result)  + ' = 0;' # Allways false
+        return '%s = 0; /* IS_EARLY_CONSTANT */' % (self.expr(op.result),)
 
     def OP_JIT_MARKER(self, op):
         return '/* JIT_MARKER %s */' % op
@@ -845,6 +845,9 @@
         return '%s = %s; /* JIT_FORCE_VIRTUAL */' % (self.expr(op.result),
                                                      self.expr(op.args[0]))
 
+    def OP_JIT_IS_VIRTUAL(self, op):
+        return '%s = 0; /* JIT_IS_VIRTUAL */' % (self.expr(op.result),)
+
     def OP_JIT_FORCE_QUASI_IMMUTABLE(self, op):
         return '/* JIT_FORCE_QUASI_IMMUTABLE %s */' % op
 
diff --git a/pypy/translator/c/src/thread_nt.h b/pypy/translator/c/src/thread_nt.h
--- a/pypy/translator/c/src/thread_nt.h
+++ b/pypy/translator/c/src/thread_nt.h
@@ -245,7 +245,7 @@
     if (pending_acquires <= 0)
         return 0;
     InterlockedIncrement(&pending_acquires);
-    PulseEvent(&cond_gil);
+    PulseEvent(cond_gil);
 
     /* hack: the three following lines do a pthread_cond_wait(), and
        normally specifying a timeout of INFINITE would be fine.  But the
@@ -253,7 +253,7 @@
        (small) risk that PulseEvent misses the WaitForSingleObject().
        In this case the process will just sleep a few milliseconds. */
     LeaveCriticalSection(&mutex_gil);
-    WaitForSingleObject(&cond_gil, 15);
+    WaitForSingleObject(cond_gil, 15);
     EnterCriticalSection(&mutex_gil);
 
     InterlockedDecrement(&pending_acquires);
@@ -263,7 +263,7 @@
 void RPyGilRelease(void)
 {
     LeaveCriticalSection(&mutex_gil);
-    PulseEvent(&cond_gil);
+    PulseEvent(cond_gil);
 }
 
 void RPyGilAcquire(void)
diff --git a/pypy/translator/platform/linux.py b/pypy/translator/platform/linux.py
--- a/pypy/translator/platform/linux.py
+++ b/pypy/translator/platform/linux.py
@@ -1,5 +1,6 @@
 """Support for Linux."""
 
+import sys
 from pypy.translator.platform.posix import BasePosix
 
 class BaseLinux(BasePosix):
@@ -24,15 +25,18 @@
         return self._pkg_config("libffi", "--libs-only-L",
                                 ['/usr/lib/libffi'])
 
+    def library_dirs_for_libffi_a(self):
+        # places where we need to look for libffi.a
+        # XXX obscuuure!  only look for libffi.a if run with translate.py
+        if 'translate' in sys.modules:
+            return self.library_dirs_for_libffi() + ['/usr/lib']
+        else:
+            return []
+
 
 class Linux(BaseLinux):
     shared_only = ()    # it seems that on 32-bit linux, compiling with -fPIC
                         # gives assembler that asmgcc is not happy about.
 
-    def library_dirs_for_libffi_a(self):
-        # places where we need to look for libffi.a
-        return self.library_dirs_for_libffi() + ['/usr/lib']
-
-
 class Linux64(BaseLinux):
     pass


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