0.10 — gcc-python-plugin 0.16 documentation (original) (raw)

gcc-python-plugin

Thanks to Buck Golemon, Daniele Varrazzo, David Narvaez, Eevee, Jason Mueller, Kevin Pyle, Matt Rice and Tom Tromey for their contributions to this release.

Changes to the GCC Python Plugin¶

• The plugin can now be used with Python 3.3 (fixing Unicode issues and dict-ordering assumptions).
• The plugin now exposes inline assembler to Python scripts viagcc.GimpleAsm.
• There is a new gccutils.sorted_callgraph() function to get the callgraph in topologically-sorted order.
• The test suite has been reworked to fix issues with checkouts on OS X case-insensitive filesystems.
• C++ support: support for locating the global namespace (aka “::”), for locating declarations and child namespaces within a namespace, and aliases.
• gcc.Declaration now has an is_builtin attribute
• Numerous improvements to the plugin’s Makefile

Improvements to gcc-with-cpychecker¶

• By default, the refcount checker is now only run on code that includes <Python.h> (implemented by checking if the “PyObject” typedef exists).
  This greatly speeds up compilation of large projects for which the Python extension modules are only a small subset of the source tree.
• Added some custom attributes for marking functions that set an exception, either always, or when returning a negative value:
  attribute((cpychecker_negative_result_sets_exception))
  attribute((cpychecker_sets_exception))
• Improve descriptions of ranges: rather than emitting descriptions with the rather vague “value”, such as:
  when considering range: 1 <= value <= 0x7fffffff
  instead try to embed a descriptive name for the value, such as:
  when considering range: 1 <= n <= 0x7fffffff

Mass recompile of Fedora 17’s Python extension code¶

I ran the reference-count checker on all of the C/C++ Python extension modules in Fedora 17 and reported hundreds of genuine problems, many of which have been fixed.

In the process of doing this I found and fixed many problems in the checker itself. For example:

• the checker now understand’s GCC’s __builtin_expect, fixing various false reports about dereferencing NULL pointers when running the checker on Cython-generated code in python-lxml-2.3
• added descriptions of part of SWIG and Cython’s internal APIs to suppress some false positives seen with SWIG and Cython-generated code.
• tweak the refcount rules to fix some false positives where the checker erroneously considered the case of a deallocation by:
  where “obj” provably had other references not owned by the function being analyzed, and thus for the case where obj->ob_refcnt > 1 the deallocation could not happen.

The plugin also now has a triaging script which can examine all of the errors within a build and provide a report, showing all of them in prioritized categories.

The source tree now contains helper scripts for conducting such a mass recompile.

C++ support¶

The checker is now able to run on C++ code: support has been added for methods, references, “this”, destructors, the gcc.GimpleNop operation.

Coverage of the CPython API¶

The format code handling for Py_BuildValue was missing support for the following codes:

• ‘u’ and ‘u#’
• ‘f’ and ‘d’
• ‘D’
• ‘c’

In addition, the handling for ‘s#’ and ‘z#’ had a bug in which it erroneously expected an int* or Py_ssize_t*, rather than just a int or Py_ssize_t.

This release fixes these issues, and gives full coverage of all valid format codes for Py_BuildValue in Python 2.

This release adds heuristics for the behavior of the following CPython API entrypoints:

• PyCode_New
• PyCObject_FromVoidPtrAndDesc
• PyDict_Size
• PyErr_Clear
• PyEval_CallMethod
• Py_FatalError
• PyFile_SoftSpace, PyFile_WriteObject, and PyFile_WriteString
• PyFloat_AsDouble and PyFloat_FromDouble
• PyFrame_New
• Py_GetVersion
• PyImport_AddModule
• PyIter_Next
• PyNumber_Int, PyNumber_Remainder
• PyObject_CallObject, PyObject_GetAttr, PyObject_GetAttrString, PyObject_GetItem, PyObject_SetAttr, and PyObject_SetAttrString
• PyOS_snprintf
• PyString_InternFromString
• PySequence_Concat, PySequence_GetSlice, PySequence_SetItem, PySequence_Size
• PySys_GetObject
• PyTraceBack_Here
• PyTuple_GetItem
• PyUnicodeUCS4_DecodeUTF8
• PyWeakref_GetObject

along with various other bugfixes.