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// Methods for Exception Support for -*- C++ -*-
// Copyright (C) 2014-2022 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
//
// ISO C++ 14882: 19.1 Exception classes
//
// Enable hooks for support for the Transactional Memory TS (N4514).
#define _GLIBCXX_TM_TS_INTERNAL
void
_txnal_cow_string_C1_for_exceptions(void* that, const char* s, void* exc);
const char*
_txnal_cow_string_c_str(const void* that);
void
_txnal_cow_string_D1(void* that);
void
_txnal_cow_string_D1_commit(void* that);
void*
_txnal_logic_error_get_msg(void* e);
void*
_txnal_runtime_error_get_msg(void* e);
// All exception classes still use the classic COW std::string.
#define _GLIBCXX_USE_CXX11_ABI 0
#define _GLIBCXX_DEFINE_STDEXCEPT_COPY_OPS 1
#define __cow_string __cow_stringxxx
#include <stdexcept>
#include <system_error>
#undef __cow_string
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// Copy/move constructors and assignment operators defined using COW string.
// These operations are noexcept even though copying a COW string is not,
// but we know that the string member in an exception has not been "leaked"
// so copying is a simple reference count increment.
logic_error::logic_error(const logic_error& e) noexcept
: exception(e), _M_msg(e._M_msg) { }
logic_error& logic_error::operator=(const logic_error& e) noexcept
{ _M_msg = e._M_msg; return *this; }
logic_error::logic_error(logic_error&& e) noexcept = default;
logic_error&
logic_error::operator=(logic_error&& e) noexcept = default;
runtime_error::runtime_error(const runtime_error& e) noexcept
: exception(e), _M_msg(e._M_msg) { }
runtime_error&
runtime_error::operator=(const runtime_error& e) noexcept
{ _M_msg = e._M_msg; return *this; }
runtime_error::runtime_error(runtime_error&& e) noexcept = default;
runtime_error&
runtime_error::operator=(runtime_error&& e) noexcept = default;
// New C++11 constructors:
logic_error::logic_error(const char* __arg)
: exception(), _M_msg(__arg) { }
domain_error::domain_error(const char* __arg)
: logic_error(__arg) { }
invalid_argument::invalid_argument(const char* __arg)
: logic_error(__arg) { }
length_error::length_error(const char* __arg)
: logic_error(__arg) { }
out_of_range::out_of_range(const char* __arg)
: logic_error(__arg) { }
runtime_error::runtime_error(const char* __arg)
: exception(), _M_msg(__arg) { }
range_error::range_error(const char* __arg)
: runtime_error(__arg) { }
overflow_error::overflow_error(const char* __arg)
: runtime_error(__arg) { }
underflow_error::underflow_error(const char* __arg)
: runtime_error(__arg) { }
#if _GLIBCXX_USE_DUAL_ABI
// Converting constructor from COW std::string to SSO string.
__sso_string::__sso_string(const string& s)
: __sso_string(s.c_str(), s.length()) { }
// Redefine __cow_string so that we can define and export its members
// in terms of the COW std::string.
struct __cow_string
{
union {
const char* _M_p;
char _M_bytes[sizeof(_M_p)];
std::string _M_str;
};
__cow_string();
__cow_string(const std::string& s);
__cow_string(const char*, size_t n);
__cow_string(const __cow_string&) noexcept;
__cow_string& operator=(const __cow_string&) noexcept;
~__cow_string();
__cow_string(__cow_string&&) noexcept;
__cow_string& operator=(__cow_string&&) noexcept;
};
__cow_string::__cow_string() : _M_str() { }
__cow_string::__cow_string(const std::string& s) : _M_str(s) { }
__cow_string::__cow_string(const char* s, size_t n) : _M_str(s, n) { }
__cow_string::__cow_string(const __cow_string& s) noexcept
: _M_str(s._M_str) { }
__cow_string&
__cow_string::operator=(const __cow_string& s) noexcept
{
_M_str = s._M_str;
return *this;
}
__cow_string::~__cow_string() { _M_str.~basic_string(); }
__cow_string::__cow_string(__cow_string&& s) noexcept
: _M_str(std::move(s._M_str)) { }
__cow_string&
__cow_string::operator=(__cow_string&& s) noexcept
{
_M_str = std::move(s._M_str);
return *this;
}
static_assert(sizeof(__cow_string) == sizeof(std::string),
"sizeof(std::string) has changed");
static_assert(alignof(__cow_string) == alignof(std::string),
"alignof(std::string) has changed");
#endif
// Return error_category::message() as an SSO string
__sso_string
error_category::_M_message(int i) const
{
string msg = this->message(i);
return {msg.c_str(), msg.length()};
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
// Support for the Transactional Memory TS (N4514).
//
// logic_error and runtime_error both carry a message in the form of a COW
// string. This COW string is never made visible to users of the exception
// because what() returns a C string. The COW string can be constructed as
// either a copy of a COW string of another logic_error/runtime_error, or
// using a C string or SSO string; thus, the COW string's _Rep is only
// accessed by logic_error operations. We control all txnal clones of those
// operations and thus can ensure that _Rep is never accessed transactionally.
// Furthermore, _Rep will always have been allocated or deallocated via
// global new or delete, so nontransactional writes we do to _Rep cannot
// interfere with transactional accesses.
// We depend on having support for referencing functions declared weak that
// are not defined by us. Without such support, the exceptions will not be
// declared transaction-safe, so we just don't provide transactional clones
// in this case.
#if _GLIBCXX_USE_WEAK_REF
#ifdef _GLIBCXX_USE_C99_STDINT_TR1
#include <stdint.h>
using std::size_t;
extern "C" {
#ifndef _GLIBCXX_MANGLE_SIZE_T
#error Mangled name of size_t type not defined.
#endif
#define CONCAT1(x,y) x##y
#define CONCAT(x,y) CONCAT1(x,y)
#define _ZGTtnaX CONCAT(_ZGTtna,_GLIBCXX_MANGLE_SIZE_T)
#ifdef __i386__
/* Only for 32-bit x86. */
# define ITM_REGPARM __attribute__((regparm(2)))
#else
# define ITM_REGPARM
#endif
// Declare all libitm symbols we rely on, but make them weak so that we do
// not depend on libitm.
extern void* _ZGTtnaX (size_t sz) __attribute__((weak));
extern void _ZGTtdlPv (void* ptr) __attribute__((weak));
extern uint8_t _ITM_RU1(const uint8_t *p)
ITM_REGPARM __attribute__((weak));
extern uint16_t _ITM_RU2(const uint16_t *p)
ITM_REGPARM __attribute__((weak));
extern uint32_t _ITM_RU4(const uint32_t *p)
ITM_REGPARM __attribute__((weak));
extern uint64_t _ITM_RU8(const uint64_t *p)
ITM_REGPARM __attribute__((weak));
extern void _ITM_memcpyRtWn(void *, const void *, size_t)
ITM_REGPARM __attribute__((weak));
extern void _ITM_memcpyRnWt(void *, const void *, size_t)
ITM_REGPARM __attribute__((weak));
extern void _ITM_addUserCommitAction(void (*)(void *), uint64_t, void *)
ITM_REGPARM __attribute__((weak));
}
// A transactional version of basic_string::basic_string(const char *s)
// that also notifies the TM runtime about allocations belonging to this
// exception.
void
_txnal_cow_string_C1_for_exceptions(void* that, const char* s,
void *exc __attribute__((unused)))
{
typedef std::basic_string<char> bs_type;
bs_type *bs = (bs_type*) that;
// First, do a transactional strlen, but including the trailing zero.
bs_type::size_type len = 1;
for (const char *ss = s; _ITM_RU1((const uint8_t*) ss) != 0; ss++, len++);
// Allocate memory for the string and the refcount. We use the
// transactional clone of global new[]; if this throws, it will do so in a
// transaction-compatible way.
// The allocation belongs to this exception, so tell the runtime about it.
// TODO Once this is supported, link the following allocation to this
// exception: void *prev = _ITM_setAssociatedException(exc);
bs_type::_Rep *rep;
__try
{
rep = (bs_type::_Rep*) _ZGTtnaX (len + sizeof (bs_type::_Rep));
}
__catch (...)
{
// Pop the association with this exception.
// TODO Once this is supported, link the following allocation to this
// exception: _ITM_setAssociatedException(prev);
// We do not need to instrument a rethrow.
__throw_exception_again;
}
// Pop the association with this exception.
// TODO Once this is supported, link the following allocation to this
// exception: _ITM_setAssociatedException(prev);
// Now initialize the rest of the string and copy the C string. The memory
// will be freshly allocated, so nontransactional accesses are sufficient,
// including the writes when copying the string (see above).
rep->_M_set_sharable();
rep->_M_length = rep->_M_capacity = len - 1;
_ITM_memcpyRtWn(rep->_M_refdata(), s, len);
new (&bs->_M_dataplus) bs_type::_Alloc_hider(rep->_M_refdata(),
bs_type::allocator_type());
}
static void* txnal_read_ptr(void* const * ptr)
{
static_assert(sizeof(uint64_t) == sizeof(void*)
|| sizeof(uint32_t) == sizeof(void*)
|| sizeof(uint16_t) == sizeof(void*),
"Pointers must be 16 bits, 32 bits or 64 bits wide");
#if __UINTPTR_MAX__ == __UINT64_MAX__
return (void*)_ITM_RU8((const uint64_t*)ptr);
#elif __UINTPTR_MAX__ == __UINT32_MAX__
return (void*)_ITM_RU4((const uint32_t*)ptr);
#else
return (void*)_ITM_RU2((const uint16_t*)ptr);
#endif
}
// We must access the data pointer in the COW string transactionally because
// another transaction can delete the string and reuse the memory.
const char*
_txnal_cow_string_c_str(const void* that)
{
typedef std::basic_string<char> bs_type;
const bs_type *bs = (const bs_type*) that;
return (const char*) txnal_read_ptr((void**)&bs->_M_dataplus._M_p);
}
#if _GLIBCXX_USE_DUAL_ABI
const char*
_txnal_sso_string_c_str(const void* that)
{
return (const char*) txnal_read_ptr(
(void* const*)const_cast<char* const*>(
&((const std::__sso_string*) that)->_M_s._M_p));
}
#endif
void
_txnal_cow_string_D1_commit(void* data)
{
typedef std::basic_string<char> bs_type;
bs_type::_Rep *rep = (bs_type::_Rep*) data;
rep->_M_dispose(bs_type::allocator_type());
}
void
_txnal_cow_string_D1(void* that)
{
typedef std::basic_string<char> bs_type;
bs_type::_Rep *rep = reinterpret_cast<bs_type::_Rep*>(
const_cast<char*>(_txnal_cow_string_c_str(that))) - 1;
// The string can be shared, in which case we would need to decrement the
// reference count. We cannot undo that because we might lose the string
// otherwise. Therefore, we register a commit action that will dispose of
// the string's _Rep.
enum {_ITM_noTransactionId = 1};
_ITM_addUserCommitAction(_txnal_cow_string_D1_commit, _ITM_noTransactionId,
rep);
}
void*
_txnal_logic_error_get_msg(void* e)
{
std::logic_error* le = (std::logic_error*) e;
return &le->_M_msg;
}
void*
_txnal_runtime_error_get_msg(void* e)
{
std::runtime_error* le = (std::runtime_error*) e;
return &le->_M_msg;
}
// The constructors are only declared transaction-safe if the C++11 ABI is
// used for std::string and the exception classes use a COW string internally.
// A user must not call these constructors otherwise; if they do, it will
// result in undefined behavior, which is in this case not initializing this
// string.
#if _GLIBCXX_USE_DUAL_ABI
#define CTORS_FROM_SSOSTRING(NAME, CLASS, BASE) \
void \
_ZGTtNSt##NAME##C1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE( \
CLASS* that, const std::__sso_string& s) \
{ \
CLASS e(""); \
_ITM_memcpyRnWt(that, &e, sizeof(CLASS)); \
/* Get the C string from the SSO string. */ \
_txnal_cow_string_C1_for_exceptions(_txnal_##BASE##_get_msg(that), \
_txnal_sso_string_c_str(&s), that); \
} \
void \
_ZGTtNSt##NAME##C2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE( \
CLASS*, const std::__sso_string&) __attribute__((alias \
("_ZGTtNSt" #NAME \
"C1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE")));
#else
#define CTORS_FROM_SSOSTRING(NAME, CLASS, BASE)
#endif
// This macro defines transaction constructors and destructors for a specific
// exception class. NAME is the variable part of the mangled name, CLASS is
// the class name, and BASE must be logic_error or runtime_error (which is
// then used to call the proper friend function that can return a pointer to
// the _M_msg member declared by the given (base) class).
#define CTORDTOR(NAME, CLASS, BASE) \
void \
_ZGTtNSt##NAME##C1EPKc (CLASS* that, const char* s) \
{ \
/* This will use the singleton _Rep for an empty string and just \
point to it instead of allocating memory. Thus, we can use it as \
source, copy it into the object we are constructing, and then \
construct the COW string in the latter manually. Note that the \
exception classes will not be declared transaction_safe if the \
shared empty _Rep is disabled with --enable-fully-dynamic-string \
(in which case _GLIBCXX_FULLY_DYNAMIC_STRING is nonzero). */ \
CLASS e(""); \
_ITM_memcpyRnWt(that, &e, sizeof(CLASS)); \
_txnal_cow_string_C1_for_exceptions(_txnal_##BASE##_get_msg(that), \
s, that); \
} \
void \
_ZGTtNSt##NAME##C2EPKc (CLASS*, const char*) \
__attribute__((alias ("_ZGTtNSt" #NAME "C1EPKc"))); \
CTORS_FROM_SSOSTRING(NAME, CLASS, BASE) \
void \
_ZGTtNSt##NAME##D1Ev(CLASS* that) \
{ _txnal_cow_string_D1(_txnal_##BASE##_get_msg(that)); } \
void \
_ZGTtNSt##NAME##D2Ev(CLASS*) \
__attribute__((alias ("_ZGTtNSt" #NAME "D1Ev"))); \
void \
_ZGTtNSt##NAME##D0Ev(CLASS* that) \
{ \
_ZGTtNSt##NAME##D1Ev(that); \
_ZGTtdlPv(that); \
}
// Now create all transactional constructors and destructors, as well as the
// two virtual what() functions.
extern "C" {
CTORDTOR(11logic_error, std::logic_error, logic_error)
const char*
_ZGTtNKSt11logic_error4whatEv(const std::logic_error* that)
{
return _txnal_cow_string_c_str(_txnal_logic_error_get_msg(
const_cast<std::logic_error*>(that)));
}
CTORDTOR(12domain_error, std::domain_error, logic_error)
CTORDTOR(16invalid_argument, std::invalid_argument, logic_error)
CTORDTOR(12length_error, std::length_error, logic_error)
CTORDTOR(12out_of_range, std::out_of_range, logic_error)
CTORDTOR(13runtime_error, std::runtime_error, runtime_error)
const char*
_ZGTtNKSt13runtime_error4whatEv(const std::runtime_error* that)
{
return _txnal_cow_string_c_str(_txnal_runtime_error_get_msg(
const_cast<std::runtime_error*>(that)));
}
CTORDTOR(11range_error, std::range_error, runtime_error)
CTORDTOR(14overflow_error, std::overflow_error, runtime_error)
CTORDTOR(15underflow_error, std::underflow_error, runtime_error)
}
#endif // _GLIBCXX_USE_C99_STDINT_TR1
#endif // _GLIBCXX_USE_WEAK_REF