[python] Fix getting section contents.

[wanders]

Summary

The returnvalue was handled as c_char_p which ment that ctypes
handled it as a NUL-terminated string making it cut the contents
at first NUL (or even worse - overrunning the buffer if it doesn't
contain a NUL).

[indygreg]

LGTM

[wanders]

Closed by commit rL207199 (authored by andersg).

llvm/trunk/bindings/python/llvm/object.py

Here are some examples on how to perform iteration:
     # Cache everything up front.
     symbols = list(obj.get_symbols(cache=True))
     for symbol in symbols:
         print symbol.name # OK
 
 """
 
 from ctypes import c_char_p
+from ctypes import c_char
+from ctypes import POINTER
 from ctypes import c_uint64
+from ctypes import string_at
 
 from .common import CachedProperty
 from .common import LLVMObject
 from .common import c_object_p
 from .common import get_library
 from .core import MemoryBuffer
 
 __all__ = [
def size(self):
 
         return lib.LLVMGetSectionSize(self)
 
     @CachedProperty
     def contents(self):
         if self.expired:
             raise Exception('Section instance has expired.')
 
-        return lib.LLVMGetSectionContents(self)
+        siz = self.size
+
+        r = lib.LLVMGetSectionContents(self)
+        if r:
+            return string_at(r, siz)
+        return None
 
     @CachedProperty
     def address(self):
         """The address of this section, in long bytes."""
         if self.expired:
             raise Exception('Section instance has expired.')
 
         return lib.LLVMGetSectionAddress(self)
def register_library(library):
 
     library.LLVMGetSectionName.argtypes = [c_object_p]
     library.LLVMGetSectionName.restype = c_char_p
 
     library.LLVMGetSectionSize.argtypes = [c_object_p]
     library.LLVMGetSectionSize.restype = c_uint64
 
     library.LLVMGetSectionContents.argtypes = [c_object_p]
-    library.LLVMGetSectionContents.restype = c_char_p
+    # Can't use c_char_p here as it isn't a NUL-terminated string.
+    library.LLVMGetSectionContents.restype = POINTER(c_char)
 
     library.LLVMGetSectionAddress.argtypes = [c_object_p]
     library.LLVMGetSectionAddress.restype = c_uint64
 
     library.LLVMGetSectionContainsSymbol.argtypes = [c_object_p, c_object_p]
     library.LLVMGetSectionContainsSymbol.restype = bool
 
     library.LLVMGetRelocations.argtypes = [c_object_p]

llvm/trunk/bindings/python/llvm/tests/test_object.py

def test_get_sections(self):
         count = 0
         for section in o.get_sections():
             count += 1
             assert isinstance(section, Section)
             assert isinstance(section.name, str)
             assert isinstance(section.size, long)
             assert isinstance(section.contents, str)
             assert isinstance(section.address, long)
+            assert len(section.contents) == section.size
 
         self.assertGreater(count, 0)
 
         for section in o.get_sections():
             section.cache()
 
     def test_get_symbols(self):
         o = self.get_object_file()