1 // Methods for Exception Support for -*- C++ -*-
3 // Copyright (C) 2014-2023 Free Software Foundation, Inc.
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)
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.
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.
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/>.
26 // ISO C++ 14882: 19.1 Exception classes
29 // Enable hooks for support for the Transactional Memory TS (N4514).
30 #define _GLIBCXX_TM_TS_INTERNAL
32 _txnal_cow_string_C1_for_exceptions(void* that
, const char* s
, void* exc
);
34 _txnal_cow_string_c_str(const void* that
);
36 _txnal_cow_string_D1(void* that
);
38 _txnal_cow_string_D1_commit(void* that
);
40 _txnal_logic_error_get_msg(void* e
);
42 _txnal_runtime_error_get_msg(void* e
);
44 // All exception classes still use the classic COW std::string.
45 #define _GLIBCXX_USE_CXX11_ABI 0
46 #define _GLIBCXX_DEFINE_STDEXCEPT_COPY_OPS 1
47 #define __cow_string __cow_stringxxx
49 #include <system_error>
52 namespace std
_GLIBCXX_VISIBILITY(default)
54 _GLIBCXX_BEGIN_NAMESPACE_VERSION
56 // Copy/move constructors and assignment operators defined using COW string.
57 // These operations are noexcept even though copying a COW string is not,
58 // but we know that the string member in an exception has not been "leaked"
59 // so copying is a simple reference count increment.
61 logic_error::logic_error(const logic_error
& e
) noexcept
62 : exception(e
), _M_msg(e
._M_msg
) { }
64 logic_error
& logic_error::operator=(const logic_error
& e
) noexcept
65 { _M_msg
= e
._M_msg
; return *this; }
67 logic_error::logic_error(logic_error
&& e
) noexcept
= default;
70 logic_error::operator=(logic_error
&& e
) noexcept
= default;
72 runtime_error::runtime_error(const runtime_error
& e
) noexcept
73 : exception(e
), _M_msg(e
._M_msg
) { }
76 runtime_error::operator=(const runtime_error
& e
) noexcept
77 { _M_msg
= e
._M_msg
; return *this; }
79 runtime_error::runtime_error(runtime_error
&& e
) noexcept
= default;
82 runtime_error::operator=(runtime_error
&& e
) noexcept
= default;
84 // New C++11 constructors:
86 logic_error::logic_error(const char* __arg
)
87 : exception(), _M_msg(__arg
) { }
89 domain_error::domain_error(const char* __arg
)
90 : logic_error(__arg
) { }
92 invalid_argument::invalid_argument(const char* __arg
)
93 : logic_error(__arg
) { }
95 length_error::length_error(const char* __arg
)
96 : logic_error(__arg
) { }
98 out_of_range::out_of_range(const char* __arg
)
99 : logic_error(__arg
) { }
101 runtime_error::runtime_error(const char* __arg
)
102 : exception(), _M_msg(__arg
) { }
104 range_error::range_error(const char* __arg
)
105 : runtime_error(__arg
) { }
107 overflow_error::overflow_error(const char* __arg
)
108 : runtime_error(__arg
) { }
110 underflow_error::underflow_error(const char* __arg
)
111 : runtime_error(__arg
) { }
113 #if _GLIBCXX_USE_DUAL_ABI
114 // Converting constructor from COW std::string to SSO string.
115 __sso_string::__sso_string(const string
& s
)
116 : __sso_string(s
.c_str(), s
.length()) { }
118 // Redefine __cow_string so that we can define and export its members
119 // in terms of the COW std::string.
124 char _M_bytes
[sizeof(_M_p
)];
129 __cow_string(const std::string
& s
);
130 __cow_string(const char*, size_t n
);
131 __cow_string(const __cow_string
&) noexcept
;
132 __cow_string
& operator=(const __cow_string
&) noexcept
;
134 __cow_string(__cow_string
&&) noexcept
;
135 __cow_string
& operator=(__cow_string
&&) noexcept
;
138 __cow_string::__cow_string() : _M_str() { }
140 __cow_string::__cow_string(const std::string
& s
) : _M_str(s
) { }
142 __cow_string::__cow_string(const char* s
, size_t n
) : _M_str(s
, n
) { }
144 __cow_string::__cow_string(const __cow_string
& s
) noexcept
145 : _M_str(s
._M_str
) { }
148 __cow_string::operator=(const __cow_string
& s
) noexcept
154 __cow_string::~__cow_string() { _M_str
.~basic_string(); }
156 __cow_string::__cow_string(__cow_string
&& s
) noexcept
157 : _M_str(std::move(s
._M_str
)) { }
160 __cow_string::operator=(__cow_string
&& s
) noexcept
162 _M_str
= std::move(s
._M_str
);
166 static_assert(sizeof(__cow_string
) == sizeof(std::string
),
167 "sizeof(std::string) has changed");
168 static_assert(alignof(__cow_string
) == alignof(std::string
),
169 "alignof(std::string) has changed");
172 // Return error_category::message() as an SSO string
174 error_category::_M_message(int i
) const
176 string msg
= this->message(i
);
177 return {msg
.c_str(), msg
.length()};
180 _GLIBCXX_END_NAMESPACE_VERSION
183 // Support for the Transactional Memory TS (N4514).
185 // logic_error and runtime_error both carry a message in the form of a COW
186 // string. This COW string is never made visible to users of the exception
187 // because what() returns a C string. The COW string can be constructed as
188 // either a copy of a COW string of another logic_error/runtime_error, or
189 // using a C string or SSO string; thus, the COW string's _Rep is only
190 // accessed by logic_error operations. We control all txnal clones of those
191 // operations and thus can ensure that _Rep is never accessed transactionally.
192 // Furthermore, _Rep will always have been allocated or deallocated via
193 // global new or delete, so nontransactional writes we do to _Rep cannot
194 // interfere with transactional accesses.
196 // We depend on having support for referencing functions declared weak that
197 // are not defined by us. Without such support, the exceptions will not be
198 // declared transaction-safe, so we just don't provide transactional clones
200 #if _GLIBCXX_USE_WEAK_REF
201 #ifdef _GLIBCXX_USE_C99_STDINT_TR1
209 #ifndef _GLIBCXX_MANGLE_SIZE_T
210 #error Mangled name of size_t type not defined.
212 #define CONCAT1(x,y) x##y
213 #define CONCAT(x,y) CONCAT1(x,y)
214 #define _ZGTtnaX CONCAT(_ZGTtna,_GLIBCXX_MANGLE_SIZE_T)
217 /* Only for 32-bit x86. */
218 # define ITM_REGPARM __attribute__((regparm(2)))
223 // Declare all libitm symbols we rely on, but make them weak so that we do
224 // not depend on libitm.
225 extern void* _ZGTtnaX (size_t sz
) __attribute__((weak
));
226 extern void _ZGTtdlPv (void* ptr
) __attribute__((weak
));
227 extern uint8_t _ITM_RU1(const uint8_t *p
)
228 ITM_REGPARM
__attribute__((weak
));
229 extern uint16_t _ITM_RU2(const uint16_t *p
)
230 ITM_REGPARM
__attribute__((weak
));
231 extern uint32_t _ITM_RU4(const uint32_t *p
)
232 ITM_REGPARM
__attribute__((weak
));
233 extern uint64_t _ITM_RU8(const uint64_t *p
)
234 ITM_REGPARM
__attribute__((weak
));
235 extern void _ITM_memcpyRtWn(void *, const void *, size_t)
236 ITM_REGPARM
__attribute__((weak
));
237 extern void _ITM_memcpyRnWt(void *, const void *, size_t)
238 ITM_REGPARM
__attribute__((weak
));
239 extern void _ITM_addUserCommitAction(void (*)(void *), uint64_t, void *)
240 ITM_REGPARM
__attribute__((weak
));
244 // A transactional version of basic_string::basic_string(const char *s)
245 // that also notifies the TM runtime about allocations belonging to this
248 _txnal_cow_string_C1_for_exceptions(void* that
, const char* s
,
249 void *exc
__attribute__((unused
)))
251 typedef std::basic_string
<char> bs_type
;
252 bs_type
*bs
= (bs_type
*) that
;
254 // First, do a transactional strlen, but including the trailing zero.
255 bs_type::size_type len
= 1;
256 for (const char *ss
= s
; _ITM_RU1((const uint8_t*) ss
) != 0; ss
++, len
++);
259 // Allocate memory for the string and the refcount. We use the
260 // transactional clone of global new[]; if this throws, it will do so in a
261 // transaction-compatible way.
262 // The allocation belongs to this exception, so tell the runtime about it.
263 // TODO Once this is supported, link the following allocation to this
264 // exception: void *prev = _ITM_setAssociatedException(exc);
268 rep
= (bs_type::_Rep
*) _ZGTtnaX (len
+ sizeof (bs_type::_Rep
));
272 // Pop the association with this exception.
273 // TODO Once this is supported, link the following allocation to this
274 // exception: _ITM_setAssociatedException(prev);
275 // We do not need to instrument a rethrow.
276 __throw_exception_again
;
278 // Pop the association with this exception.
279 // TODO Once this is supported, link the following allocation to this
280 // exception: _ITM_setAssociatedException(prev);
282 // Now initialize the rest of the string and copy the C string. The memory
283 // will be freshly allocated, so nontransactional accesses are sufficient,
284 // including the writes when copying the string (see above).
285 rep
->_M_set_sharable();
286 rep
->_M_length
= rep
->_M_capacity
= len
- 1;
287 _ITM_memcpyRtWn(rep
->_M_refdata(), s
, len
);
288 new (&bs
->_M_dataplus
) bs_type::_Alloc_hider(rep
->_M_refdata(),
289 bs_type::allocator_type());
292 static void* txnal_read_ptr(void* const * ptr
)
294 static_assert(sizeof(uint64_t) == sizeof(void*)
295 || sizeof(uint32_t) == sizeof(void*)
296 || sizeof(uint16_t) == sizeof(void*),
297 "Pointers must be 16 bits, 32 bits or 64 bits wide");
298 #if __UINTPTR_MAX__ == __UINT64_MAX__
299 return (void*)_ITM_RU8((const uint64_t*)ptr
);
300 #elif __UINTPTR_MAX__ == __UINT32_MAX__
301 return (void*)_ITM_RU4((const uint32_t*)ptr
);
303 return (void*)_ITM_RU2((const uint16_t*)ptr
);
307 // We must access the data pointer in the COW string transactionally because
308 // another transaction can delete the string and reuse the memory.
310 _txnal_cow_string_c_str(const void* that
)
312 typedef std::basic_string
<char> bs_type
;
313 const bs_type
*bs
= (const bs_type
*) that
;
315 return (const char*) txnal_read_ptr((void**)&bs
->_M_dataplus
._M_p
);
318 #if _GLIBCXX_USE_DUAL_ABI
320 _txnal_sso_string_c_str(const void* that
)
322 return (const char*) txnal_read_ptr(
323 (void* const*)const_cast<char* const*>(
324 &((const std::__sso_string
*) that
)->_M_s
._M_p
));
329 _txnal_cow_string_D1_commit(void* data
)
331 typedef std::basic_string
<char> bs_type
;
332 bs_type::_Rep
*rep
= (bs_type::_Rep
*) data
;
333 rep
->_M_dispose(bs_type::allocator_type());
337 _txnal_cow_string_D1(void* that
)
339 typedef std::basic_string
<char> bs_type
;
340 bs_type::_Rep
*rep
= reinterpret_cast<bs_type::_Rep
*>(
341 const_cast<char*>(_txnal_cow_string_c_str(that
))) - 1;
343 // The string can be shared, in which case we would need to decrement the
344 // reference count. We cannot undo that because we might lose the string
345 // otherwise. Therefore, we register a commit action that will dispose of
346 // the string's _Rep.
347 enum {_ITM_noTransactionId
= 1};
348 _ITM_addUserCommitAction(_txnal_cow_string_D1_commit
, _ITM_noTransactionId
,
353 _txnal_logic_error_get_msg(void* e
)
355 std::logic_error
* le
= (std::logic_error
*) e
;
360 _txnal_runtime_error_get_msg(void* e
)
362 std::runtime_error
* le
= (std::runtime_error
*) e
;
366 // The constructors are only declared transaction-safe if the C++11 ABI is
367 // used for std::string and the exception classes use a COW string internally.
368 // A user must not call these constructors otherwise; if they do, it will
369 // result in undefined behavior, which is in this case not initializing this
371 #if _GLIBCXX_USE_DUAL_ABI
372 #define CTORS_FROM_SSOSTRING(NAME, CLASS, BASE) \
374 _ZGTtNSt##NAME##C1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE( \
375 CLASS* that, const std::__sso_string& s) \
378 _ITM_memcpyRnWt(that, &e, sizeof(CLASS)); \
379 /* Get the C string from the SSO string. */ \
380 _txnal_cow_string_C1_for_exceptions(_txnal_##BASE##_get_msg(that), \
381 _txnal_sso_string_c_str(&s), that); \
384 _ZGTtNSt##NAME##C2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE( \
385 CLASS*, const std::__sso_string&) __attribute__((alias \
387 "C1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE")));
389 #define CTORS_FROM_SSOSTRING(NAME, CLASS, BASE)
392 // This macro defines transaction constructors and destructors for a specific
393 // exception class. NAME is the variable part of the mangled name, CLASS is
394 // the class name, and BASE must be logic_error or runtime_error (which is
395 // then used to call the proper friend function that can return a pointer to
396 // the _M_msg member declared by the given (base) class).
397 #define CTORDTOR(NAME, CLASS, BASE) \
399 _ZGTtNSt##NAME##C1EPKc (CLASS* that, const char* s) \
401 /* This will use the singleton _Rep for an empty string and just \
402 point to it instead of allocating memory. Thus, we can use it as \
403 source, copy it into the object we are constructing, and then \
404 construct the COW string in the latter manually. Note that the \
405 exception classes will not be declared transaction_safe if the \
406 shared empty _Rep is disabled with --enable-fully-dynamic-string \
407 (in which case _GLIBCXX_FULLY_DYNAMIC_STRING is nonzero). */ \
409 _ITM_memcpyRnWt(that, &e, sizeof(CLASS)); \
410 _txnal_cow_string_C1_for_exceptions(_txnal_##BASE##_get_msg(that), \
414 _ZGTtNSt##NAME##C2EPKc (CLASS*, const char*) \
415 __attribute__((alias ("_ZGTtNSt" #NAME "C1EPKc"))); \
416 CTORS_FROM_SSOSTRING(NAME, CLASS, BASE) \
418 _ZGTtNSt##NAME##D1Ev(CLASS* that) \
419 { _txnal_cow_string_D1(_txnal_##BASE##_get_msg(that)); } \
421 _ZGTtNSt##NAME##D2Ev(CLASS*) \
422 __attribute__((alias ("_ZGTtNSt" #NAME "D1Ev"))); \
424 _ZGTtNSt##NAME##D0Ev(CLASS* that) \
426 _ZGTtNSt##NAME##D1Ev(that); \
430 // Now create all transactional constructors and destructors, as well as the
431 // two virtual what() functions.
434 CTORDTOR(11logic_error
, std::logic_error
, logic_error
)
437 _ZGTtNKSt11logic_error4whatEv(const std::logic_error
* that
)
439 return _txnal_cow_string_c_str(_txnal_logic_error_get_msg(
440 const_cast<std::logic_error
*>(that
)));
443 CTORDTOR(12domain_error
, std::domain_error
, logic_error
)
444 CTORDTOR(16invalid_argument
, std::invalid_argument
, logic_error
)
445 CTORDTOR(12length_error
, std::length_error
, logic_error
)
446 CTORDTOR(12out_of_range
, std::out_of_range
, logic_error
)
449 CTORDTOR(13runtime_error
, std::runtime_error
, runtime_error
)
452 _ZGTtNKSt13runtime_error4whatEv(const std::runtime_error
* that
)
454 return _txnal_cow_string_c_str(_txnal_runtime_error_get_msg(
455 const_cast<std::runtime_error
*>(that
)));
458 CTORDTOR(11range_error
, std::range_error
, runtime_error
)
459 CTORDTOR(14overflow_error
, std::overflow_error
, runtime_error
)
460 CTORDTOR(15underflow_error
, std::underflow_error
, runtime_error
)
464 #endif // _GLIBCXX_USE_C99_STDINT_TR1
465 #endif // _GLIBCXX_USE_WEAK_REF