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| #===- common.py - Python LLVM Bindings -----------------------*- python -*--===#
#
# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
# See https://llvm.org/LICENSE.txt for license information.
# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#
#===------------------------------------------------------------------------===#
from ctypes import POINTER
from ctypes import c_void_p
from ctypes import cdll
import ctypes.util
import platform
# LLVM_VERSION: sync with PACKAGE_VERSION in CMakeLists.txt
# but leave out the 'svn' suffix.
LLVM_VERSION = '10.0.0'
__all__ = [
'c_object_p',
'get_library',
]
c_object_p = POINTER(c_void_p)
class LLVMObject(object):
"""Base class for objects that are backed by an LLVM data structure.
This class should never be instantiated outside of this package.
"""
def __init__(self, ptr, ownable=True, disposer=None):
assert isinstance(ptr, c_object_p)
self._ptr = self._as_parameter_ = ptr
self._self_owned = True
self._ownable = ownable
self._disposer = disposer
self._owned_objects = []
def take_ownership(self, obj):
"""Take ownership of another object.
When you take ownership of another object, you are responsible for
destroying that object. In addition, a reference to that object is
placed inside this object so the Python garbage collector will not
collect the object while it is still alive in libLLVM.
This method should likely only be called from within modules inside
this package.
"""
assert isinstance(obj, LLVMObject)
self._owned_objects.append(obj)
obj._self_owned = False
def from_param(self):
"""ctypes function that converts this object to a function parameter."""
return self._as_parameter_
def __del__(self):
if not hasattr(self, '_self_owned') or not hasattr(self, '_disposer'):
return
if self._self_owned and self._disposer:
self._disposer(self)
class CachedProperty(object):
"""Decorator that caches the result of a property lookup.
This is a useful replacement for @property. It is recommended to use this
decorator on properties that invoke C API calls for which the result of the
call will be idempotent.
"""
def __init__(self, wrapped):
self.wrapped = wrapped
try:
self.__doc__ = wrapped.__doc__
except: # pragma: no cover
pass
def __get__(self, instance, instance_type=None):
if instance is None:
return self
value = self.wrapped(instance)
setattr(instance, self.wrapped.__name__, value)
return value
def get_library():
"""Obtain a reference to the llvm library."""
# On Linux, ctypes.cdll.LoadLibrary() respects LD_LIBRARY_PATH
# while ctypes.util.find_library() doesn't.
# See http://docs.python.org/2/library/ctypes.html#finding-shared-libraries
#
# To make it possible to run the unit tests without installing the LLVM shared
# library into a default linker search path. Always Try ctypes.cdll.LoadLibrary()
# with all possible library names first, then try ctypes.util.find_library().
names = ['LLVM-' + LLVM_VERSION, 'LLVM-' + LLVM_VERSION + 'svn']
t = platform.system()
if t == 'Darwin':
pfx, ext = 'lib', '.dylib'
elif t == 'Windows':
pfx, ext = '', '.dll'
else:
pfx, ext = 'lib', '.so'
for i in names:
try:
lib = cdll.LoadLibrary(pfx + i + ext)
except OSError:
pass
else:
return lib
for i in names:
t = ctypes.util.find_library(i)
if t:
return cdll.LoadLibrary(t)
raise Exception('LLVM shared library not found!')
|