# PyPy2.7 v5.4

We have released PyPy2.7 v5.4, a little under two months after PyPy2.7 v5.3. This new PyPy2.7 release includes incremental improvements to our C-API compatibility layer (cpyext), enabling us to pass over 99% of the upstream numpy test suite. We updated built-in cffi support to version 1.8, which now supports the "limited API" mode for c-extensions on CPython >=3.2.

We improved tooling for the PyPy JIT, and expanded VMProf support to OpenBSD and Dragon Fly BSD

As always, this release fixed many issues and bugs raised by the growing community of PyPy users. We strongly recommend updating.

You can download the PyPy2.7 v5.4 release here:

> https://pypy.org/download.html

We would like to thank our donors for the continued support of the PyPy project.

We would also like to thank our contributors and encourage new people to join the project. PyPy has many layers and we need help with all of them: PyPy and RPython documentation improvements, tweaking popular modules to run on pypy, or general help with making RPython's JIT even better.

## What is PyPy?

PyPy is a very compliant Python interpreter, almost a drop-in replacement for CPython 2.7. It's fast (PyPy and CPython 2.7.x performance comparison) due to its integrated tracing JIT compiler.

We also welcome developers of other dynamic languages to see what RPython can do for them.

This release supports:

> - x86 machines on most common operating systems (Linux 32/64 bits, Mac OS X 64 bits, Windows 32 bits, OpenBSD, FreeBSD)

> - newer ARM hardware (ARMv6 or ARMv7, with VFPv3) running Linux,

> - big- and little-endian variants of PPC64 running Linux,

> - s390x running Linux

## Other Highlights (since 5.3 released in June 2016)

- New features:

  - Add sys.{get,set}dlopenflags

  - Improve CPython compatibility of 'is' for small and empty strings

  - Support for rgc.FinalizerQueue in the Boehm garbage collector

  - (RPython) support spawnv() if it is called in C _spawnv on windows

  - Fill in more slots when creating a PyTypeObject from a W_TypeObject, like __hex__, __sub__, __pow__

  - Copy CPython's logic more closely for isinstance() and issubclass() as well as type.__instancecheck__() and type.__subclasscheck__()

  - Expose the name of CDLL objects

  - Rewrite the win32 dependencies of subprocess to use cffi instead of ctypes

  - Improve the JIT logging facitilities

  - (RPython) make int * string work

  - Allocate all RPython strings with one extra byte, normally unused. This now allows ffi.from_buffer(string) in CFFI with no copy

  - Adds a new commandline option -X track-resources that will produce a ResourceWarning when the GC closes a file or socket. The traceback for the place where the file or socket was allocated is given as well, which aids finding places where close() is missing

  - Add missing PyObject_Realloc, PySequence_GetSlice

  - type.__dict__ now returns a dict_proxy object, like on CPython. Previously it returned what looked like a regular dict object (but it was already read-only)

  - (RPython) add rposix.{get,set}_inheritable(), needed by Python 3.5

  - (RPython) add rposix_scandir portably, needed for Python 3.5

  - Increased but incomplete support for memoryview attributes (format, itemsize, ...) which also adds support for PyMemoryView_FromObject

- Bug Fixes

  - Reject mkdir() in read-only sandbox filesystems

  - Add include guards to pymem.h to enable c++ compilation

  - Fix build breakage on OpenBSD and FreeBSD

  - Support OpenBSD, Dragon Fly BSD in VMProf

  - Fix for bytearray('').replace('a', 'ab') for empty strings

  - Sync internal state before calling PyFile_AsFile()

  - Allow writing to a char* from PyString_AsString() until it is forced, also refactor PyStringObject to look like CPython's and allow subclassing PyString_Type and PyUnicode_Type

  - Rpython rffi's socket(2) wrapper did not preserve errno

  - Refactor PyTupleObject to look like CPython's and allow subclassing PyTuple_Type

  - Allow c-level assignment to a function pointer in a C-API user-defined type after calling PyTypeReady by retrieving a pointer to the function via offsets rather than storing the function pointer itself

  - Use madvise(MADV_FREE), or if that doesn't exist MADV_DONTNEED on freed arenas to release memory back to the OS for resource monitoring

  - Fix overflow detection in conversion of float to 64-bit integer in timeout argument to various thread/threading primitives

  - Fix win32 outputting rrn in some cases

  - Make hash(-1) return -2, as CPython does, and fix all the ancilary places this matters

  - Fix PyNumber_Check() to behave more like CPython

  - (VMProf) Try hard to not miss any Python-level frame in the captured stacks, even if there is metainterp or blackhole interp involved. Also fix the stacklet (greenlet) support

  - Fix a critical JIT bug where raw_malloc -equivalent functions lost the additional flags

  - Fix the mapdict cache for subclasses of builtin types that provide a dict

  - Issues reported with our previous release were resolved after reports from users on our issue tracker at https://bitbucket.org/pypy/pypy/issues or on IRC at #pypy

- Performance improvements:

  - Add a before_call()-like equivalent before a few operations like malloc_nursery, to move values from registers into other registers instead of to the stack.

  - More tightly pack the stack when calling with release gil

  - Support int_floordiv(), int_mod() in the JIT more efficiently and add rarithmetic.int_c_div(), rarithmetic.int_c_mod() as explicit interfaces. Clarify that int_floordiv() does python-style rounding, unlike llop.int_floordiv().

  - Use ll_assert (more often) in incminimark

  - (Testing) Simplify handling of interp-level tests and make it more forward-compatible. Don't use interp-level RPython machinery to test building app-level extensions in cpyext

  - Constant-fold ffi.offsetof("structname", "fieldname") in cffi backend

  - Avoid a case in the JIT, where successive guard failures in the same Python function end up as successive levels of RPython functions, eventually exhausting the stack, while at app-level the traceback is very short

  - Check for NULL returns from calls to the raw-malloc and raise, rather than a guard

  - Improve socket.recvfrom() so that it copies less if possible

  - When generating C code, inline goto to blocks with only one predecessor, generating less lines of code

  - When running the final backend-optimization phase before emitting C code, constant-fold calls to we_are_jitted to return False. This makes the generated C code a few percent smaller

  - Refactor the uid_t/gid_t handling in rlib.rposix and in interp_posix.py, based on the clean-up of CPython 2.7.x

Please update, and continue to help us make PyPy better.

Cheers