Pavel Labath 7f09ab08de [lldb] Fix [some] leaks in python bindings
Using an lldb_private object in the bindings involves three steps
- wrapping the object in it's lldb::SB variant
- using swig to convert/wrap that to a PyObject
- wrapping *that* in a lldb_private::python::PythonObject

Our SBTypeToSWIGWrapper was only handling the middle part. This doesn't
just result in increased boilerplate in the callers, but is also a
functionality problem, as it's very hard to get the lifetime of of all
of these objects right. Most of the callers are creating the SB object
(step 1) on the stack, which means that we end up with dangling python
objects after the function terminates. Most of the time this isn't a
problem, because the python code does not need to persist the objects.
However, there are legitimate cases where they can do it (and even if
the use case is not completely legitimate, crashing is not the best
response to that).

For this reason, some of our code creates the SB object on the heap, but
it has another problem -- it never gets cleaned up.

This patch begins to add a new function (ToSWIGWrapper), which does all
of the three steps, while properly taking care of ownership. In the
first step, I have converted most of the leaky code (except for
SBStructuredData, which needs a bit more work).

Differential Revision: https://reviews.llvm.org/D114259
2021-11-22 15:14:52 +01:00

298 lines
9.5 KiB
C++

//===-- PythonTestSuite.cpp -----------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "gtest/gtest.h"
#include "Plugins/ScriptInterpreter/Python/lldb-python.h"
#include "Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h"
#include "Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h"
#include "lldb/Host/FileSystem.h"
#include "lldb/Host/HostInfo.h"
#include "PythonTestSuite.h"
using namespace lldb_private;
class TestScriptInterpreterPython : public ScriptInterpreterPythonImpl {
public:
using ScriptInterpreterPythonImpl::Initialize;
using ScriptInterpreterPythonImpl::InitializePrivate;
};
void PythonTestSuite::SetUp() {
FileSystem::Initialize();
HostInfoBase::Initialize();
// ScriptInterpreterPython::Initialize() depends on HostInfo being
// initializedso it can compute the python directory etc.
TestScriptInterpreterPython::Initialize();
TestScriptInterpreterPython::InitializePrivate();
// Although we don't care about concurrency for the purposes of running
// this test suite, Python requires the GIL to be locked even for
// deallocating memory, which can happen when you call Py_DECREF or
// Py_INCREF. So acquire the GIL for the entire duration of this
// test suite.
m_gil_state = PyGILState_Ensure();
}
void PythonTestSuite::TearDown() {
PyGILState_Release(m_gil_state);
TestScriptInterpreterPython::Terminate();
HostInfoBase::Terminate();
FileSystem::Terminate();
}
// The following functions are the Pythonic implementations of the required
// callbacks. Because they're defined in libLLDB which we cannot link for the
// unit test, we have a 'default' implementation here.
#if PY_MAJOR_VERSION >= 3
extern "C" PyObject *PyInit__lldb(void) { return nullptr; }
#define LLDBSwigPyInit PyInit__lldb
#else
extern "C" void init_lldb(void) {}
#define LLDBSwigPyInit init_lldb
#endif
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
// Disable warning C4190: 'LLDBSwigPythonBreakpointCallbackFunction' has
// C-linkage specified, but returns UDT 'llvm::Expected<bool>' which is
// incompatible with C
#if _MSC_VER
#pragma warning (push)
#pragma warning (disable : 4190)
#endif
extern "C" llvm::Expected<bool> LLDBSwigPythonBreakpointCallbackFunction(
const char *python_function_name, const char *session_dictionary_name,
const lldb::StackFrameSP &sb_frame,
const lldb::BreakpointLocationSP &sb_bp_loc,
StructuredDataImpl *args_impl) {
return false;
}
#if _MSC_VER
#pragma warning (pop)
#endif
#pragma clang diagnostic pop
extern "C" bool LLDBSwigPythonWatchpointCallbackFunction(
const char *python_function_name, const char *session_dictionary_name,
const lldb::StackFrameSP &sb_frame, const lldb::WatchpointSP &sb_wp) {
return false;
}
extern "C" bool LLDBSwigPythonCallTypeScript(
const char *python_function_name, void *session_dictionary,
const lldb::ValueObjectSP &valobj_sp, void **pyfunct_wrapper,
const lldb::TypeSummaryOptionsSP &options_sp, std::string &retval) {
return false;
}
extern "C" void *
LLDBSwigPythonCreateSyntheticProvider(const char *python_class_name,
const char *session_dictionary_name,
const lldb::ValueObjectSP &valobj_sp) {
return nullptr;
}
extern "C" void *
LLDBSwigPythonCreateCommandObject(const char *python_class_name,
const char *session_dictionary_name,
const lldb::DebuggerSP debugger_sp) {
return nullptr;
}
extern "C" void *LLDBSwigPythonCreateScriptedThreadPlan(
const char *python_class_name, const char *session_dictionary_name,
StructuredDataImpl *args_data,
std::string &error_string,
const lldb::ThreadPlanSP &thread_plan_sp) {
return nullptr;
}
extern "C" bool LLDBSWIGPythonCallThreadPlan(void *implementor,
const char *method_name,
Event *event_sp, bool &got_error) {
return false;
}
extern "C" void *LLDBSwigPythonCreateScriptedBreakpointResolver(
const char *python_class_name, const char *session_dictionary_name,
lldb_private::StructuredDataImpl *args, const lldb::BreakpointSP &bkpt_sp) {
return nullptr;
}
extern "C" unsigned int
LLDBSwigPythonCallBreakpointResolver(void *implementor, const char *method_name,
lldb_private::SymbolContext *sym_ctx) {
return 0;
}
extern "C" size_t LLDBSwigPython_CalculateNumChildren(void *implementor,
uint32_t max) {
return 0;
}
extern "C" void *LLDBSwigPython_GetChildAtIndex(void *implementor,
uint32_t idx) {
return nullptr;
}
extern "C" int LLDBSwigPython_GetIndexOfChildWithName(void *implementor,
const char *child_name) {
return 0;
}
extern "C" void *LLDBSWIGPython_CastPyObjectToSBData(void *data) {
return nullptr;
}
extern "C" void *LLDBSWIGPython_CastPyObjectToSBError(void *data) {
return nullptr;
}
extern "C" void *LLDBSWIGPython_CastPyObjectToSBValue(void *data) {
return nullptr;
}
extern "C" void *LLDBSWIGPython_CastPyObjectToSBMemoryRegionInfo(void *data) {
return nullptr;
}
extern lldb::ValueObjectSP
LLDBSWIGPython_GetValueObjectSPFromSBValue(void *data) {
return nullptr;
}
extern "C" bool LLDBSwigPython_UpdateSynthProviderInstance(void *implementor) {
return false;
}
extern "C" bool
LLDBSwigPython_MightHaveChildrenSynthProviderInstance(void *implementor) {
return false;
}
extern "C" void *
LLDBSwigPython_GetValueSynthProviderInstance(void *implementor) {
return nullptr;
}
extern "C" bool
LLDBSwigPythonCallCommand(const char *python_function_name,
const char *session_dictionary_name,
lldb::DebuggerSP &debugger, const char *args,
lldb_private::CommandReturnObject &cmd_retobj,
lldb::ExecutionContextRefSP exe_ctx_ref_sp) {
return false;
}
extern "C" bool
LLDBSwigPythonCallCommandObject(void *implementor, lldb::DebuggerSP &debugger,
const char *args,
lldb_private::CommandReturnObject &cmd_retobj,
lldb::ExecutionContextRefSP exe_ctx_ref_sp) {
return false;
}
extern "C" bool
LLDBSwigPythonCallModuleInit(const char *python_module_name,
const char *session_dictionary_name,
lldb::DebuggerSP &debugger) {
return false;
}
extern "C" void *
LLDBSWIGPythonCreateOSPlugin(const char *python_class_name,
const char *session_dictionary_name,
const lldb::ProcessSP &process_sp) {
return nullptr;
}
extern "C" void *LLDBSwigPythonCreateScriptedProcess(
const char *python_class_name, const char *session_dictionary_name,
const lldb::TargetSP &target_sp, StructuredDataImpl *args_impl,
std::string &error_string) {
return nullptr;
}
extern "C" void *LLDBSwigPythonCreateScriptedThread(
const char *python_class_name, const char *session_dictionary_name,
const lldb::ProcessSP &process_sp, StructuredDataImpl *args_impl,
std::string &error_string) {
return nullptr;
}
extern "C" void *
LLDBSWIGPython_CreateFrameRecognizer(const char *python_class_name,
const char *session_dictionary_name) {
return nullptr;
}
extern "C" void *
LLDBSwigPython_GetRecognizedArguments(void *implementor,
const lldb::StackFrameSP &frame_sp) {
return nullptr;
}
extern "C" bool LLDBSWIGPythonRunScriptKeywordProcess(
const char *python_function_name, const char *session_dictionary_name,
const lldb::ProcessSP &process, std::string &output) {
return false;
}
extern "C" bool LLDBSWIGPythonRunScriptKeywordThread(
const char *python_function_name, const char *session_dictionary_name,
lldb::ThreadSP &thread, std::string &output) {
return false;
}
extern "C" bool LLDBSWIGPythonRunScriptKeywordTarget(
const char *python_function_name, const char *session_dictionary_name,
const lldb::TargetSP &target, std::string &output) {
return false;
}
extern "C" bool LLDBSWIGPythonRunScriptKeywordFrame(
const char *python_function_name, const char *session_dictionary_name,
lldb::StackFrameSP &frame, std::string &output) {
return false;
}
extern "C" bool LLDBSWIGPythonRunScriptKeywordValue(
const char *python_function_name, const char *session_dictionary_name,
const lldb::ValueObjectSP &value, std::string &output) {
return false;
}
extern "C" void *
LLDBSWIGPython_GetDynamicSetting(void *module, const char *setting,
const lldb::TargetSP &target_sp) {
return nullptr;
}
extern "C" void *LLDBSwigPythonCreateScriptedStopHook(
lldb::TargetSP target_sp, const char *python_class_name,
const char *session_dictionary_name,
lldb_private::StructuredDataImpl *args_impl, Status &error) {
return nullptr;
}
extern "C" bool
LLDBSwigPythonStopHookCallHandleStop(void *implementor,
lldb::ExecutionContextRefSP exc_ctx_sp,
lldb::StreamSP stream) {
return false;
}