Bug Summary

File:build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/Support/Parallel.cpp
Warning:line 166, column 49
Potential memory leak

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name Parallel.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm -resource-dir /usr/lib/llvm-16/lib/clang/16.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I lib/Support -I /build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/Support -I include -I /build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/include -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-16/lib/clang/16.0.0/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm=build-llvm -fmacro-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/= -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm=build-llvm -fcoverage-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/= -O3 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/build-llvm=build-llvm -fdebug-prefix-map=/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2022-09-04-125545-48738-1 -x c++ /build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/Support/Parallel.cpp

/build/llvm-toolchain-snapshot-16~++20220904122748+c444af1c20b3/llvm/lib/Support/Parallel.cpp

1//===- llvm/Support/Parallel.cpp - Parallel algorithms --------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "llvm/Support/Parallel.h"
10#include "llvm/Config/llvm-config.h"
11#include "llvm/Support/ManagedStatic.h"
12#include "llvm/Support/Threading.h"
13
14#include <atomic>
15#include <future>
16#include <stack>
17#include <thread>
18#include <vector>
19
20llvm::ThreadPoolStrategy llvm::parallel::strategy;
21
22namespace llvm {
23namespace parallel {
24#if LLVM_ENABLE_THREADS1
25namespace detail {
26
27namespace {
28
29/// An abstract class that takes closures and runs them asynchronously.
30class Executor {
31public:
32 virtual ~Executor() = default;
33 virtual void add(std::function<void()> func) = 0;
34
35 static Executor *getDefaultExecutor();
36};
37
38/// An implementation of an Executor that runs closures on a thread pool
39/// in filo order.
40class ThreadPoolExecutor : public Executor {
41public:
42 explicit ThreadPoolExecutor(ThreadPoolStrategy S = hardware_concurrency()) {
43 unsigned ThreadCount = S.compute_thread_count();
44 // Spawn all but one of the threads in another thread as spawning threads
45 // can take a while.
46 Threads.reserve(ThreadCount);
47 Threads.resize(1);
48 std::lock_guard<std::mutex> Lock(Mutex);
49 Threads[0] = std::thread([this, ThreadCount, S] {
50 for (unsigned I = 1; I < ThreadCount; ++I) {
51 Threads.emplace_back([=] { work(S, I); });
52 if (Stop)
53 break;
54 }
55 ThreadsCreated.set_value();
56 work(S, 0);
57 });
58 }
59
60 void stop() {
61 {
62 std::lock_guard<std::mutex> Lock(Mutex);
63 if (Stop)
64 return;
65 Stop = true;
66 }
67 Cond.notify_all();
68 ThreadsCreated.get_future().wait();
69 }
70
71 ~ThreadPoolExecutor() override {
72 stop();
73 std::thread::id CurrentThreadId = std::this_thread::get_id();
74 for (std::thread &T : Threads)
75 if (T.get_id() == CurrentThreadId)
76 T.detach();
77 else
78 T.join();
79 }
80
81 struct Creator {
82 static void *call() { return new ThreadPoolExecutor(strategy); }
83 };
84 struct Deleter {
85 static void call(void *Ptr) { ((ThreadPoolExecutor *)Ptr)->stop(); }
86 };
87
88 void add(std::function<void()> F) override {
89 {
90 std::lock_guard<std::mutex> Lock(Mutex);
91 WorkStack.push(std::move(F));
92 }
93 Cond.notify_one();
94 }
95
96private:
97 void work(ThreadPoolStrategy S, unsigned ThreadID) {
98 S.apply_thread_strategy(ThreadID);
99 while (true) {
100 std::unique_lock<std::mutex> Lock(Mutex);
101 Cond.wait(Lock, [&] { return Stop || !WorkStack.empty(); });
102 if (Stop)
103 break;
104 auto Task = std::move(WorkStack.top());
105 WorkStack.pop();
106 Lock.unlock();
107 Task();
108 }
109 }
110
111 std::atomic<bool> Stop{false};
112 std::stack<std::function<void()>> WorkStack;
113 std::mutex Mutex;
114 std::condition_variable Cond;
115 std::promise<void> ThreadsCreated;
116 std::vector<std::thread> Threads;
117};
118
119Executor *Executor::getDefaultExecutor() {
120 // The ManagedStatic enables the ThreadPoolExecutor to be stopped via
121 // llvm_shutdown() which allows a "clean" fast exit, e.g. via _exit(). This
122 // stops the thread pool and waits for any worker thread creation to complete
123 // but does not wait for the threads to finish. The wait for worker thread
124 // creation to complete is important as it prevents intermittent crashes on
125 // Windows due to a race condition between thread creation and process exit.
126 //
127 // The ThreadPoolExecutor will only be destroyed when the static unique_ptr to
128 // it is destroyed, i.e. in a normal full exit. The ThreadPoolExecutor
129 // destructor ensures it has been stopped and waits for worker threads to
130 // finish. The wait is important as it prevents intermittent crashes on
131 // Windows when the process is doing a full exit.
132 //
133 // The Windows crashes appear to only occur with the MSVC static runtimes and
134 // are more frequent with the debug static runtime.
135 //
136 // This also prevents intermittent deadlocks on exit with the MinGW runtime.
137
138 static ManagedStatic<ThreadPoolExecutor, ThreadPoolExecutor::Creator,
139 ThreadPoolExecutor::Deleter>
140 ManagedExec;
141 static std::unique_ptr<ThreadPoolExecutor> Exec(&(*ManagedExec));
142 return Exec.get();
143}
144} // namespace
145} // namespace detail
146#endif
147
148static std::atomic<int> TaskGroupInstances;
149
150// Latch::sync() called by the dtor may cause one thread to block. If is a dead
151// lock if all threads in the default executor are blocked. To prevent the dead
152// lock, only allow the first TaskGroup to run tasks parallelly. In the scenario
153// of nested parallel_for_each(), only the outermost one runs parallelly.
154TaskGroup::TaskGroup() : Parallel(TaskGroupInstances++ == 0) {}
155TaskGroup::~TaskGroup() {
156 // We must ensure that all the workloads have finished before decrementing the
157 // instances count.
158 L.sync();
159 --TaskGroupInstances;
160}
161
162void TaskGroup::spawn(std::function<void()> F) {
163#if LLVM_ENABLE_THREADS1
164 if (Parallel) {
17
Assuming field 'Parallel' is true
18
Taking true branch
165 L.inc();
166 detail::Executor::getDefaultExecutor()->add([&, F = std::move(F)] {
19
Potential memory leak
167 F();
168 L.dec();
169 });
170 return;
171 }
172#endif
173 F();
174}
175
176void TaskGroup::execute(std::function<void()> F) {
177 if (parallel::strategy.ThreadsRequested == 1)
178 F();
179 else
180 spawn(F);
181}
182} // namespace parallel
183} // namespace llvm
184
185void llvm::parallelFor(size_t Begin, size_t End,
186 llvm::function_ref<void(size_t)> Fn) {
187 // If we have zero or one items, then do not incur the overhead of spinning up
188 // a task group. They are surprisingly expensive, and because they do not
189 // support nested parallelism, a single entry task group can block parallel
190 // execution underneath them.
191#if LLVM_ENABLE_THREADS1
192 auto NumItems = End - Begin;
193 if (NumItems > 1 && parallel::strategy.ThreadsRequested != 1) {
1
Assuming 'NumItems' is > 1
2
Assuming field 'ThreadsRequested' is not equal to 1
3
Taking true branch
194 // Limit the number of tasks to MaxTasksPerGroup to limit job scheduling
195 // overhead on large inputs.
196 auto TaskSize = NumItems / parallel::detail::MaxTasksPerGroup;
197 if (TaskSize == 0)
4
Assuming 'TaskSize' is not equal to 0
5
Taking false branch
198 TaskSize = 1;
199
200 parallel::TaskGroup TG;
201 for (; Begin + TaskSize < End; Begin += TaskSize) {
6
Assuming the condition is true
7
Loop condition is true. Entering loop body
202 TG.spawn([=, &Fn] {
8
Calling constructor for 'function<void ()>'
15
Returning from constructor for 'function<void ()>'
16
Calling 'TaskGroup::spawn'
203 for (size_t I = Begin, E = Begin + TaskSize; I != E; ++I)
204 Fn(I);
205 });
206 }
207 for (; Begin != End; ++Begin)
208 Fn(Begin);
209 return;
210 }
211#endif
212
213 for (; Begin != End; ++Begin)
214 Fn(Begin);
215}

/usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/bits/std_function.h

1// Implementation of std::function -*- C++ -*-
2
3// Copyright (C) 2004-2020 Free Software Foundation, Inc.
4//
5// This file is part of the GNU ISO C++ Library. This library is free
6// software; you can redistribute it and/or modify it under the
7// terms of the GNU General Public License as published by the
8// Free Software Foundation; either version 3, or (at your option)
9// any later version.
10
11// This library is distributed in the hope that it will be useful,
12// but WITHOUT ANY WARRANTY; without even the implied warranty of
13// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14// GNU General Public License for more details.
15
16// Under Section 7 of GPL version 3, you are granted additional
17// permissions described in the GCC Runtime Library Exception, version
18// 3.1, as published by the Free Software Foundation.
19
20// You should have received a copy of the GNU General Public License and
21// a copy of the GCC Runtime Library Exception along with this program;
22// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23// <http://www.gnu.org/licenses/>.
24
25/** @file include/bits/std_function.h
26 * This is an internal header file, included by other library headers.
27 * Do not attempt to use it directly. @headername{functional}
28 */
29
30#ifndef _GLIBCXX_STD_FUNCTION_H1
31#define _GLIBCXX_STD_FUNCTION_H1 1
32
33#pragma GCC system_header
34
35#if __cplusplus201703L < 201103L
36# include <bits/c++0x_warning.h>
37#else
38
39#if __cpp_rtti199711L
40# include <typeinfo>
41#endif
42#include <bits/stl_function.h>
43#include <bits/invoke.h>
44#include <bits/refwrap.h>
45#include <bits/functexcept.h>
46
47namespace std _GLIBCXX_VISIBILITY(default)__attribute__ ((__visibility__ ("default")))
48{
49_GLIBCXX_BEGIN_NAMESPACE_VERSION
50
51 /**
52 * @brief Exception class thrown when class template function's
53 * operator() is called with an empty target.
54 * @ingroup exceptions
55 */
56 class bad_function_call : public std::exception
57 {
58 public:
59 virtual ~bad_function_call() noexcept;
60
61 const char* what() const noexcept;
62 };
63
64 /**
65 * Trait identifying "location-invariant" types, meaning that the
66 * address of the object (or any of its members) will not escape.
67 * Trivially copyable types are location-invariant and users can
68 * specialize this trait for other types.
69 */
70 template<typename _Tp>
71 struct __is_location_invariant
72 : is_trivially_copyable<_Tp>::type
73 { };
74
75 class _Undefined_class;
76
77 union _Nocopy_types
78 {
79 void* _M_object;
80 const void* _M_const_object;
81 void (*_M_function_pointer)();
82 void (_Undefined_class::*_M_member_pointer)();
83 };
84
85 union [[gnu::may_alias]] _Any_data
86 {
87 void* _M_access() { return &_M_pod_data[0]; }
88 const void* _M_access() const { return &_M_pod_data[0]; }
89
90 template<typename _Tp>
91 _Tp&
92 _M_access()
93 { return *static_cast<_Tp*>(_M_access()); }
94
95 template<typename _Tp>
96 const _Tp&
97 _M_access() const
98 { return *static_cast<const _Tp*>(_M_access()); }
99
100 _Nocopy_types _M_unused;
101 char _M_pod_data[sizeof(_Nocopy_types)];
102 };
103
104 enum _Manager_operation
105 {
106 __get_type_info,
107 __get_functor_ptr,
108 __clone_functor,
109 __destroy_functor
110 };
111
112 template<typename _Signature>
113 class function;
114
115 /// Base class of all polymorphic function object wrappers.
116 class _Function_base
117 {
118 public:
119 static const size_t _M_max_size = sizeof(_Nocopy_types);
120 static const size_t _M_max_align = __alignof__(_Nocopy_types);
121
122 template<typename _Functor>
123 class _Base_manager
124 {
125 protected:
126 static const bool __stored_locally =
127 (__is_location_invariant<_Functor>::value
128 && sizeof(_Functor) <= _M_max_size
129 && __alignof__(_Functor) <= _M_max_align
130 && (_M_max_align % __alignof__(_Functor) == 0));
131
132 typedef integral_constant<bool, __stored_locally> _Local_storage;
133
134 // Retrieve a pointer to the function object
135 static _Functor*
136 _M_get_pointer(const _Any_data& __source)
137 {
138 if _GLIBCXX17_CONSTEXPRconstexpr (__stored_locally)
139 {
140 const _Functor& __f = __source._M_access<_Functor>();
141 return const_cast<_Functor*>(std::__addressof(__f));
142 }
143 else // have stored a pointer
144 return __source._M_access<_Functor*>();
145 }
146
147 // Clone a location-invariant function object that fits within
148 // an _Any_data structure.
149 static void
150 _M_clone(_Any_data& __dest, const _Any_data& __source, true_type)
151 {
152 ::new (__dest._M_access()) _Functor(__source._M_access<_Functor>());
153 }
154
155 // Clone a function object that is not location-invariant or
156 // that cannot fit into an _Any_data structure.
157 static void
158 _M_clone(_Any_data& __dest, const _Any_data& __source, false_type)
159 {
160 __dest._M_access<_Functor*>() =
161 new _Functor(*__source._M_access<const _Functor*>());
162 }
163
164 // Destroying a location-invariant object may still require
165 // destruction.
166 static void
167 _M_destroy(_Any_data& __victim, true_type)
168 {
169 __victim._M_access<_Functor>().~_Functor();
170 }
171
172 // Destroying an object located on the heap.
173 static void
174 _M_destroy(_Any_data& __victim, false_type)
175 {
176 delete __victim._M_access<_Functor*>();
177 }
178
179 public:
180 static bool
181 _M_manager(_Any_data& __dest, const _Any_data& __source,
182 _Manager_operation __op)
183 {
184 switch (__op)
185 {
186#if __cpp_rtti199711L
187 case __get_type_info:
188 __dest._M_access<const type_info*>() = &typeid(_Functor);
189 break;
190#endif
191 case __get_functor_ptr:
192 __dest._M_access<_Functor*>() = _M_get_pointer(__source);
193 break;
194
195 case __clone_functor:
196 _M_clone(__dest, __source, _Local_storage());
197 break;
198
199 case __destroy_functor:
200 _M_destroy(__dest, _Local_storage());
201 break;
202 }
203 return false;
204 }
205
206 static void
207 _M_init_functor(_Any_data& __functor, _Functor&& __f)
208 { _M_init_functor(__functor, std::move(__f), _Local_storage()); }
11
Calling '_Base_manager::_M_init_functor'
13
Returned allocated memory
209
210 template<typename _Signature>
211 static bool
212 _M_not_empty_function(const function<_Signature>& __f)
213 { return static_cast<bool>(__f); }
214
215 template<typename _Tp>
216 static bool
217 _M_not_empty_function(_Tp* __fp)
218 { return __fp != nullptr; }
219
220 template<typename _Class, typename _Tp>
221 static bool
222 _M_not_empty_function(_Tp _Class::* __mp)
223 { return __mp != nullptr; }
224
225 template<typename _Tp>
226 static bool
227 _M_not_empty_function(const _Tp&)
228 { return true; }
229
230 private:
231 static void
232 _M_init_functor(_Any_data& __functor, _Functor&& __f, true_type)
233 { ::new (__functor._M_access()) _Functor(std::move(__f)); }
234
235 static void
236 _M_init_functor(_Any_data& __functor, _Functor&& __f, false_type)
237 { __functor._M_access<_Functor*>() = new _Functor(std::move(__f)); }
12
Memory is allocated
238 };
239
240 _Function_base() : _M_manager(nullptr) { }
241
242 ~_Function_base()
243 {
244 if (_M_manager)
245 _M_manager(_M_functor, _M_functor, __destroy_functor);
246 }
247
248 bool _M_empty() const { return !_M_manager; }
249
250 typedef bool (*_Manager_type)(_Any_data&, const _Any_data&,
251 _Manager_operation);
252
253 _Any_data _M_functor;
254 _Manager_type _M_manager;
255 };
256
257 template<typename _Signature, typename _Functor>
258 class _Function_handler;
259
260 template<typename _Res, typename _Functor, typename... _ArgTypes>
261 class _Function_handler<_Res(_ArgTypes...), _Functor>
262 : public _Function_base::_Base_manager<_Functor>
263 {
264 typedef _Function_base::_Base_manager<_Functor> _Base;
265
266 public:
267 static bool
268 _M_manager(_Any_data& __dest, const _Any_data& __source,
269 _Manager_operation __op)
270 {
271 switch (__op)
272 {
273#if __cpp_rtti199711L
274 case __get_type_info:
275 __dest._M_access<const type_info*>() = &typeid(_Functor);
276 break;
277#endif
278 case __get_functor_ptr:
279 __dest._M_access<_Functor*>() = _Base::_M_get_pointer(__source);
280 break;
281
282 default:
283 _Base::_M_manager(__dest, __source, __op);
284 }
285 return false;
286 }
287
288 static _Res
289 _M_invoke(const _Any_data& __functor, _ArgTypes&&... __args)
290 {
291 return std::__invoke_r<_Res>(*_Base::_M_get_pointer(__functor),
292 std::forward<_ArgTypes>(__args)...);
293 }
294 };
295
296 /**
297 * @brief Primary class template for std::function.
298 * @ingroup functors
299 *
300 * Polymorphic function wrapper.
301 */
302 template<typename _Res, typename... _ArgTypes>
303 class function<_Res(_ArgTypes...)>
304 : public _Maybe_unary_or_binary_function<_Res, _ArgTypes...>,
305 private _Function_base
306 {
307 template<typename _Func,
308 typename _Res2 = __invoke_result<_Func&, _ArgTypes...>>
309 struct _Callable
310 : __is_invocable_impl<_Res2, _Res>::type
311 { };
312
313 // Used so the return type convertibility checks aren't done when
314 // performing overload resolution for copy construction/assignment.
315 template<typename _Tp>
316 struct _Callable<function, _Tp> : false_type { };
317
318 template<typename _Cond, typename _Tp>
319 using _Requires = typename enable_if<_Cond::value, _Tp>::type;
320
321 public:
322 typedef _Res result_type;
323
324 // [3.7.2.1] construct/copy/destroy
325
326 /**
327 * @brief Default construct creates an empty function call wrapper.
328 * @post @c !(bool)*this
329 */
330 function() noexcept
331 : _Function_base() { }
332
333 /**
334 * @brief Creates an empty function call wrapper.
335 * @post @c !(bool)*this
336 */
337 function(nullptr_t) noexcept
338 : _Function_base() { }
339
340 /**
341 * @brief %Function copy constructor.
342 * @param __x A %function object with identical call signature.
343 * @post @c bool(*this) == bool(__x)
344 *
345 * The newly-created %function contains a copy of the target of @a
346 * __x (if it has one).
347 */
348 function(const function& __x);
349
350 /**
351 * @brief %Function move constructor.
352 * @param __x A %function object rvalue with identical call signature.
353 *
354 * The newly-created %function contains the target of @a __x
355 * (if it has one).
356 */
357 function(function&& __x) noexcept : _Function_base()
358 {
359 __x.swap(*this);
360 }
361
362 /**
363 * @brief Builds a %function that targets a copy of the incoming
364 * function object.
365 * @param __f A %function object that is callable with parameters of
366 * type @c T1, @c T2, ..., @c TN and returns a value convertible
367 * to @c Res.
368 *
369 * The newly-created %function object will target a copy of
370 * @a __f. If @a __f is @c reference_wrapper<F>, then this function
371 * object will contain a reference to the function object @c
372 * __f.get(). If @a __f is a NULL function pointer or NULL
373 * pointer-to-member, the newly-created object will be empty.
374 *
375 * If @a __f is a non-NULL function pointer or an object of type @c
376 * reference_wrapper<F>, this function will not throw.
377 */
378 template<typename _Functor,
379 typename = _Requires<__not_<is_same<_Functor, function>>, void>,
380 typename = _Requires<_Callable<_Functor>, void>>
381 function(_Functor);
382
383 /**
384 * @brief %Function assignment operator.
385 * @param __x A %function with identical call signature.
386 * @post @c (bool)*this == (bool)x
387 * @returns @c *this
388 *
389 * The target of @a __x is copied to @c *this. If @a __x has no
390 * target, then @c *this will be empty.
391 *
392 * If @a __x targets a function pointer or a reference to a function
393 * object, then this operation will not throw an %exception.
394 */
395 function&
396 operator=(const function& __x)
397 {
398 function(__x).swap(*this);
399 return *this;
400 }
401
402 /**
403 * @brief %Function move-assignment operator.
404 * @param __x A %function rvalue with identical call signature.
405 * @returns @c *this
406 *
407 * The target of @a __x is moved to @c *this. If @a __x has no
408 * target, then @c *this will be empty.
409 *
410 * If @a __x targets a function pointer or a reference to a function
411 * object, then this operation will not throw an %exception.
412 */
413 function&
414 operator=(function&& __x) noexcept
415 {
416 function(std::move(__x)).swap(*this);
417 return *this;
418 }
419
420 /**
421 * @brief %Function assignment to zero.
422 * @post @c !(bool)*this
423 * @returns @c *this
424 *
425 * The target of @c *this is deallocated, leaving it empty.
426 */
427 function&
428 operator=(nullptr_t) noexcept
429 {
430 if (_M_manager)
431 {
432 _M_manager(_M_functor, _M_functor, __destroy_functor);
433 _M_manager = nullptr;
434 _M_invoker = nullptr;
435 }
436 return *this;
437 }
438
439 /**
440 * @brief %Function assignment to a new target.
441 * @param __f A %function object that is callable with parameters of
442 * type @c T1, @c T2, ..., @c TN and returns a value convertible
443 * to @c Res.
444 * @return @c *this
445 *
446 * This %function object wrapper will target a copy of @a
447 * __f. If @a __f is @c reference_wrapper<F>, then this function
448 * object will contain a reference to the function object @c
449 * __f.get(). If @a __f is a NULL function pointer or NULL
450 * pointer-to-member, @c this object will be empty.
451 *
452 * If @a __f is a non-NULL function pointer or an object of type @c
453 * reference_wrapper<F>, this function will not throw.
454 */
455 template<typename _Functor>
456 _Requires<_Callable<typename decay<_Functor>::type>, function&>
457 operator=(_Functor&& __f)
458 {
459 function(std::forward<_Functor>(__f)).swap(*this);
460 return *this;
461 }
462
463 /// @overload
464 template<typename _Functor>
465 function&
466 operator=(reference_wrapper<_Functor> __f) noexcept
467 {
468 function(__f).swap(*this);
469 return *this;
470 }
471
472 // [3.7.2.2] function modifiers
473
474 /**
475 * @brief Swap the targets of two %function objects.
476 * @param __x A %function with identical call signature.
477 *
478 * Swap the targets of @c this function object and @a __f. This
479 * function will not throw an %exception.
480 */
481 void swap(function& __x) noexcept
482 {
483 std::swap(_M_functor, __x._M_functor);
484 std::swap(_M_manager, __x._M_manager);
485 std::swap(_M_invoker, __x._M_invoker);
486 }
487
488 // [3.7.2.3] function capacity
489
490 /**
491 * @brief Determine if the %function wrapper has a target.
492 *
493 * @return @c true when this %function object contains a target,
494 * or @c false when it is empty.
495 *
496 * This function will not throw an %exception.
497 */
498 explicit operator bool() const noexcept
499 { return !_M_empty(); }
500
501 // [3.7.2.4] function invocation
502
503 /**
504 * @brief Invokes the function targeted by @c *this.
505 * @returns the result of the target.
506 * @throws bad_function_call when @c !(bool)*this
507 *
508 * The function call operator invokes the target function object
509 * stored by @c this.
510 */
511 _Res operator()(_ArgTypes... __args) const;
512
513#if __cpp_rtti199711L
514 // [3.7.2.5] function target access
515 /**
516 * @brief Determine the type of the target of this function object
517 * wrapper.
518 *
519 * @returns the type identifier of the target function object, or
520 * @c typeid(void) if @c !(bool)*this.
521 *
522 * This function will not throw an %exception.
523 */
524 const type_info& target_type() const noexcept;
525
526 /**
527 * @brief Access the stored target function object.
528 *
529 * @return Returns a pointer to the stored target function object,
530 * if @c typeid(_Functor).equals(target_type()); otherwise, a NULL
531 * pointer.
532 *
533 * This function does not throw exceptions.
534 *
535 * @{
536 */
537 template<typename _Functor> _Functor* target() noexcept;
538
539 template<typename _Functor> const _Functor* target() const noexcept;
540 // @}
541#endif
542
543 private:
544 using _Invoker_type = _Res (*)(const _Any_data&, _ArgTypes&&...);
545 _Invoker_type _M_invoker;
546 };
547
548#if __cpp_deduction_guides201703L >= 201606
549 template<typename>
550 struct __function_guide_helper
551 { };
552
553 template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
554 struct __function_guide_helper<
555 _Res (_Tp::*) (_Args...) noexcept(_Nx)
556 >
557 { using type = _Res(_Args...); };
558
559 template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
560 struct __function_guide_helper<
561 _Res (_Tp::*) (_Args...) & noexcept(_Nx)
562 >
563 { using type = _Res(_Args...); };
564
565 template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
566 struct __function_guide_helper<
567 _Res (_Tp::*) (_Args...) const noexcept(_Nx)
568 >
569 { using type = _Res(_Args...); };
570
571 template<typename _Res, typename _Tp, bool _Nx, typename... _Args>
572 struct __function_guide_helper<
573 _Res (_Tp::*) (_Args...) const & noexcept(_Nx)
574 >
575 { using type = _Res(_Args...); };
576
577 template<typename _Res, typename... _ArgTypes>
578 function(_Res(*)(_ArgTypes...)) -> function<_Res(_ArgTypes...)>;
579
580 template<typename _Functor, typename _Signature = typename
581 __function_guide_helper<decltype(&_Functor::operator())>::type>
582 function(_Functor) -> function<_Signature>;
583#endif
584
585 // Out-of-line member definitions.
586 template<typename _Res, typename... _ArgTypes>
587 function<_Res(_ArgTypes...)>::
588 function(const function& __x)
589 : _Function_base()
590 {
591 if (static_cast<bool>(__x))
592 {
593 __x._M_manager(_M_functor, __x._M_functor, __clone_functor);
594 _M_invoker = __x._M_invoker;
595 _M_manager = __x._M_manager;
596 }
597 }
598
599 template<typename _Res, typename... _ArgTypes>
600 template<typename _Functor, typename, typename>
601 function<_Res(_ArgTypes...)>::
602 function(_Functor __f)
603 : _Function_base()
604 {
605 typedef _Function_handler<_Res(_ArgTypes...), _Functor> _My_handler;
606
607 if (_My_handler::_M_not_empty_function(__f))
9
Taking true branch
608 {
609 _My_handler::_M_init_functor(_M_functor, std::move(__f));
10
Calling '_Base_manager::_M_init_functor'
14
Returned allocated memory
610 _M_invoker = &_My_handler::_M_invoke;
611 _M_manager = &_My_handler::_M_manager;
612 }
613 }
614
615 template<typename _Res, typename... _ArgTypes>
616 _Res
617 function<_Res(_ArgTypes...)>::
618 operator()(_ArgTypes... __args) const
619 {
620 if (_M_empty())
621 __throw_bad_function_call();
622 return _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
623 }
624
625#if __cpp_rtti199711L
626 template<typename _Res, typename... _ArgTypes>
627 const type_info&
628 function<_Res(_ArgTypes...)>::
629 target_type() const noexcept
630 {
631 if (_M_manager)
632 {
633 _Any_data __typeinfo_result;
634 _M_manager(__typeinfo_result, _M_functor, __get_type_info);
635 return *__typeinfo_result._M_access<const type_info*>();
636 }
637 else
638 return typeid(void);
639 }
640
641 template<typename _Res, typename... _ArgTypes>
642 template<typename _Functor>
643 _Functor*
644 function<_Res(_ArgTypes...)>::
645 target() noexcept
646 {
647 const function* __const_this = this;
648 const _Functor* __func = __const_this->template target<_Functor>();
649 return const_cast<_Functor*>(__func);
650 }
651
652 template<typename _Res, typename... _ArgTypes>
653 template<typename _Functor>
654 const _Functor*
655 function<_Res(_ArgTypes...)>::
656 target() const noexcept
657 {
658 if (typeid(_Functor) == target_type() && _M_manager)
659 {
660 _Any_data __ptr;
661 _M_manager(__ptr, _M_functor, __get_functor_ptr);
662 return __ptr._M_access<const _Functor*>();
663 }
664 else
665 return nullptr;
666 }
667#endif
668
669 // [20.7.15.2.6] null pointer comparisons
670
671 /**
672 * @brief Compares a polymorphic function object wrapper against 0
673 * (the NULL pointer).
674 * @returns @c true if the wrapper has no target, @c false otherwise
675 *
676 * This function will not throw an %exception.
677 */
678 template<typename _Res, typename... _Args>
679 inline bool
680 operator==(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
681 { return !static_cast<bool>(__f); }
682
683#if __cpp_impl_three_way_comparison < 201907L
684 /// @overload
685 template<typename _Res, typename... _Args>
686 inline bool
687 operator==(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
688 { return !static_cast<bool>(__f); }
689
690 /**
691 * @brief Compares a polymorphic function object wrapper against 0
692 * (the NULL pointer).
693 * @returns @c false if the wrapper has no target, @c true otherwise
694 *
695 * This function will not throw an %exception.
696 */
697 template<typename _Res, typename... _Args>
698 inline bool
699 operator!=(const function<_Res(_Args...)>& __f, nullptr_t) noexcept
700 { return static_cast<bool>(__f); }
701
702 /// @overload
703 template<typename _Res, typename... _Args>
704 inline bool
705 operator!=(nullptr_t, const function<_Res(_Args...)>& __f) noexcept
706 { return static_cast<bool>(__f); }
707#endif
708
709 // [20.7.15.2.7] specialized algorithms
710
711 /**
712 * @brief Swap the targets of two polymorphic function object wrappers.
713 *
714 * This function will not throw an %exception.
715 */
716 // _GLIBCXX_RESOLVE_LIB_DEFECTS
717 // 2062. Effect contradictions w/o no-throw guarantee of std::function swaps
718 template<typename _Res, typename... _Args>
719 inline void
720 swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y) noexcept
721 { __x.swap(__y); }
722
723#if __cplusplus201703L >= 201703L
724 namespace __detail::__variant
725 {
726 template<typename> struct _Never_valueless_alt; // see <variant>
727
728 // Provide the strong exception-safety guarantee when emplacing a
729 // function into a variant.
730 template<typename _Signature>
731 struct _Never_valueless_alt<std::function<_Signature>>
732 : std::true_type
733 { };
734 } // namespace __detail::__variant
735#endif // C++17
736
737_GLIBCXX_END_NAMESPACE_VERSION
738} // namespace std
739
740#endif // C++11
741#endif // _GLIBCXX_STD_FUNCTION_H