godot/core/os/thread.h
Hein-Pieter van Braam-Stewart ff3099abcf Fix thread_local, tls, ASLR, and DEP with MingW
This commit changes the way Thread::caller_id works. By moving caller_id
to the .cpp file we make sure that the TLS variable doesn't get
relocated twice causing a crash. Since we build with LTO for release
builds (and everyone should be doing that anyway) there is no extra
overhead from the non-static method. We do do an extra bool check now
there but I don't think this will add much in the way of overhead.

This check cannot be avoided if we still want to be able to cache the
thread ID hash, as we had to move the setter because of limitations of
the WinRT platform. The original workaround for this was in #46813 but
this has some unintended consequences. Specifically; threads that never
create a Thread object will always return 0 in Thread::get_caller_id()
which caused a regression. For instance the editor now freezes when
importing large textures. This PR also addresses that.

Additionally we now enable ASLR support when building with MingW, this
includes a workaround for MingW. MingW refuses to create an appropriate
relocation table if no symbols are exported. So we just export the
various main() functions in godot_windows.cpp.

While ASLR support isn't criticial for Godot, previous versions of Godot
just happened to work with a dynamic base 'by accident' and some users
run Godot this way. After the thread change the .tls section now needs
relocations to make this work. By enabling ASLR at build-time we create
these relocations and people who forced ALSR on previously will now get
a working Godot again.

This fixes #47256 and fixes #47219

This is the 3.x version of this PR. For master a different approach is
possible which I will make in the coming days.
2021-03-25 23:20:12 +01:00

117 lines
4.2 KiB
C++

/*************************************************************************/
/* thread.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#ifndef THREAD_H
#define THREAD_H
#include "core/typedefs.h"
#if !defined(NO_THREADS)
#include "core/safe_refcount.h"
#include <thread>
#endif
class String;
class Thread {
public:
typedef void (*Callback)(void *p_userdata);
typedef uint64_t ID;
enum Priority {
PRIORITY_LOW,
PRIORITY_NORMAL,
PRIORITY_HIGH
};
struct Settings {
Priority priority;
Settings() { priority = PRIORITY_NORMAL; }
};
private:
#if !defined(NO_THREADS)
friend class Main;
static ID main_thread_id;
static uint64_t _thread_id_hash(const std::thread::id &p_t);
ID id = _thread_id_hash(std::thread::id());
std::thread thread;
static void callback(Thread *p_self, const Settings &p_settings, Thread::Callback p_callback, void *p_userdata);
static Error (*set_name_func)(const String &);
static void (*set_priority_func)(Thread::Priority);
static void (*init_func)();
static void (*term_func)();
#endif
public:
static void _set_platform_funcs(
Error (*p_set_name_func)(const String &),
void (*p_set_priority_func)(Thread::Priority),
void (*p_init_func)() = nullptr,
void (*p_term_func)() = nullptr);
#if !defined(NO_THREADS)
_FORCE_INLINE_ ID get_id() const { return id; }
// get the ID of the caller thread
static ID get_caller_id();
// get the ID of the main thread
_FORCE_INLINE_ static ID get_main_id() { return main_thread_id; }
static Error set_name(const String &p_name);
void start(Thread::Callback p_callback, void *p_user, const Settings &p_settings = Settings());
bool is_started() const;
///< waits until thread is finished, and deallocates it.
void wait_to_finish();
~Thread();
#else
_FORCE_INLINE_ ID get_id() const { return 0; }
// get the ID of the caller thread
_FORCE_INLINE_ static ID get_caller_id() { return 0; }
// get the ID of the main thread
_FORCE_INLINE_ static ID get_main_id() { return 0; }
static Error set_name(const String &p_name) { return ERR_UNAVAILABLE; }
void start(Thread::Callback p_callback, void *p_user, const Settings &p_settings = Settings()) {}
bool is_started() const { return false; }
void wait_to_finish() {}
#endif
};
#endif // THREAD_H