Summary:
Along with this, support for an optional argument to the "num_children"
method of a Python synthetic child provider has also been added. These have
been added with the following use case in mind:
Synthetic child providers currently have a method "has_children" and
"num_children". While the former is good enough to know if there are
children, it does not give any insight into how many children there are.
Though the latter serves this purpose, calculating the number for children
of a data structure could be an O(N) operation if the data structure has N
children. The new method added in this change provide a middle ground.
One can call GetNumChildren(K) to know if a child exists at an index K
which can be as large as the callers tolerance can be. If the caller wants
to know about children beyond K, it can make an other call with 2K. If the
synthetic child provider maintains state about it counting till K
previosly, then the next call is only an O(K) operation. Infact, all
calls made progressively with steps of K will be O(K) operations.
Reviewers: vharron, clayborg, granata.enrico
Subscribers: labath, lldb-commits
Differential Revision: http://reviews.llvm.org/D13778
llvm-svn: 250930
Python file handling got an overhaul in Python 3, and it affects
the way we have to interact with files. Notably:
1) `PyFile_FromFile` no longer exists, and instead we have to use
`PyFile_FromFd`. This means having a way to get an fd from
a FILE*. For this we reuse the lldb_private::File class to
convert between FILE*s and fds, since there are some subtleties
regarding ownership rules when FILE*s and fds refer to the same
file.
2) PyFile is no longer a builtin type, so there is no such thing as
`PyFile_Check`. Instead, files in Python 3 are just instances
of `io.IOBase`. So the logic for checking if something is a file
in Python 3 is to check if it is a subclass of that module.
Additionally, some unit tests are added to verify that `PythonFile`
works as expected on Python 2 and Python 3, and
`ScriptInterpreterPython` is updated to use `PythonFile` instead of
manual calls to the various `PyFile_XXX` methods.
llvm-svn: 250444
PythonObjects were being incorrectly ref-counted. This problem was
pervasive throughout the codebase, leading to an unknown number of memory
leaks and potentially use-after-free.
The issue stems from the fact that Python native methods can either return
"borrowed" references or "owned" references. For the former category, you
*must* incref it prior to decrefing it. And for the latter category, you
should not incref it before decrefing it. This is mostly an issue when a
Python C API method returns a `PyObject` to you, but it can also happen with
a method accepts a `PyObject`. Notably, this happens in `PyList_SetItem`,
which is documented to "steal" the reference that you give it. So if you
pass something to `PyList_SetItem`, you cannot hold onto it unless you
incref it first. But since this is one of only two exceptions in the
entire API, it's confusing and difficult to remember.
Our `PythonObject` class was indiscriminantely increfing every object it
received, which means that if you passed it an owned reference, you now
have a dangling reference since owned references should not be increfed.
We were doing this in quite a few places.
There was also a fair amount of manual increfing and decrefing prevalent
throughout the codebase, which is easy to get wrong.
This patch solves the problem by making any construction of a
`PythonObject` from a `PyObject` take a flag which indicates whether it is
an owned reference or a borrowed reference. There is no way to construct a
`PythonObject` without this flag, and it does not offer a default value,
forcing the user to make an explicit decision every time.
All manual uses of `PyObject` have been cleaned up throughout the codebase
and replaced with `PythonObject` in order to make RAII the predominant
pattern when dealing with native Python objects.
Differential Revision: http://reviews.llvm.org/D13617
Reviewed By: Greg Clayton
llvm-svn: 250195
This is the work done by Ryan Brown from http://reviews.llvm.org/D8712 that makes a TypeSystem class and abstracts types to be able to use a type system.
All tests pass on MacOSX and passed on linux the last time this was submitted.
llvm-svn: 244679
Previously embedded interpreters were handled as ad-hoc source
files compiled into source/Interpreter. This made it hard to
disable a specific interpreter, or to add support for other
interpreters and allow the developer to choose which interpreter(s)
were enabled for a particular build.
This patch converts script interpreters over to a plugin-based system.
Script interpreters now live in source/Plugins/ScriptInterpreter, and
the canonical LLDB interpreter, ScriptInterpreterPython, is moved there
as well.
Any new code interfacing with the Python C API must live in this location
from here on out. Additionally, generic code should never need to
reference or make assumptions about the presence of a specific interpreter
going forward.
Differential Revision: http://reviews.llvm.org/D11431
Reviewed By: Greg Clayton
llvm-svn: 243681
