If rewriter encounter a situation which can't be handled. It will set
the `failed` to `true`. In this situation, just stop to emit code. And
also don't check some assert.

Some scipy related fixing.

Enable function.func_closure and function.__new__

In Pyston, has_getattribute got set if __getattribute__ is overridden,
but only tp_getattro is supposed to set __getattribute__ and tp_getattr
will not set it. So add a check to update_one_slot, if type->tp_getattr
is not NULL, don't set has_getattribute to False.

enable the clang travis CI build again

This reverts commit d1b799e5.

Fixes part of #1263

The function PyCFunction_GetFunction(func) check func type should be
exactly PyCFunction_Type. PyCFunction_GET_FUNCTION(func) does not check
func type. But assumes func layout starts with PyCFunctionObject. i.e.
for allowing func to be PyCFunction_Type subclass.

This way an extension which subclasses PyCFunctionObject will get
into trouble using PyCFunction_GET_FUNCTION() on Pyston

Add some helper API to Pyston.

rewriter+bjit: remove duplicate getattrs, misc codegen improvements

this saves a few bytes by replacing some movabs imm64, reg with smaller instructions

before when we allocated scratch space we always needed one more reg to store the address of the scratch space
this address is a constant stack offset so this was not needed because it can be recalculated like to a constant value

e.g. relative or absolute using a temp register

this transform some xdecrefs to decrefs
and removes some calls of assertNameDefinedHelper

problem was that the bumped the variable to late which caused an extra spill

I think we need a place to test new added C API. And Pyston missed
PySet_Size implementation(already declared it). Add and test it.

Add more line numbers

We've been a bit lazy about adding line numbers to all ast nodes.
This is an inconvenience when the tracebacks are bad/wrong, and it's
also causing issues for testing code that wants to look at the line
at which something failed.

So I added line numbers to a whole bunch more nodes.  There are still
quite a few that don't have line numbers, but many of them are harmless,
so I tried to identify the ones that matter.  I also added some assertions
to make sure that bad (non-positive) line numbers don't escape to the user.

This issue is that type analysis is stronger than irgen.
Specifically here, type analysis knows that the phi isn't required
and propagates the type across BB's, but irgen conservatively promotes
to UNKNOWN.

Fix some leaks related to signals

The IR we generated looked something like this:

1: i64 %a = doIC()
2: checkPendingCalls()
3: Box* %b = (Box*)%b

The problem is that the refcounter only knew about %b, starting on
line 3.  So for line 2, the refcounter didn't think it needed to decref
%a if an exception was thrown.

So the first thing this commit does is it adds check that when we refcount-track
a value, if it is a cast, then the cast must be right next to the thing it is casting.
This is stricter than we need but it should be easy enough to do and be sufficient.

Another approach would have been to have the refcount checker be able to track the
non-box-like values, ie track %a in the above example.  This would need some checking
to make sure that people didn't forget to track that.  In the end I thought this would
be simpler.

The second thing is it adds a helper function createAfter that inserts the cast in
the right location.  This could have worked by having createIC do the casting itself.
But this was a little bit tricky since some callers want to know the Instruction of the
call itself, and if createIC only returned the cast then those would get confused.  It
could have returned both, but that seemed complicated.

We would leak refs if an exception was thrown via the pending-calls handler.

Previously we would print out all leaked objects at program exit.
But this is problematic since it includes both directly leaked objects
(the ones we are interested in), and indirectly leaked objects
(which only got leaked by being referenced from another leaked object).

This uses the cycle collector infrastructure to figure out what objects
have non-heap, ie leaked, references remaining.  Hopefully this should
help us debug cases where there are hundreds of objects remaining.

perf: add a script which allows 'perf report' to disassemble JITed functions

In Pyston the PyCodeObject just an opaque pointer. Which can't calculate
the number of freevars. Implement a function to check whether there has
freevars in BoxedCode object.

Remove redefinition error in pyport.h

add prefix to Pyston defined True and False

download cython from github instead of cython.org

cython.org is currently down

The current pyport.h missed somethings due to it started with an empty pyport.h. And add things
increfmentally from CPython, now copied all things in CPython pyport.h.