diff options
Diffstat (limited to 'libstdc++-v3/src/c++11/cow-stdexcept.cc')
| -rw-r--r-- | libstdc++-v3/src/c++11/cow-stdexcept.cc | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/libstdc++-v3/src/c++11/cow-stdexcept.cc b/libstdc++-v3/src/c++11/cow-stdexcept.cc index 782b96c6d4f..eddb36b48c4 100644 --- a/libstdc++-v3/src/c++11/cow-stdexcept.cc +++ b/libstdc++-v3/src/c++11/cow-stdexcept.cc @@ -26,6 +26,21 @@ // 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 @@ -151,3 +166,278 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION _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. +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 + +#if __GXX_WEAK__ +// 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 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)); + +#else +// If there is no support for weak symbols, create dummies. The exceptions +// will not be declared transaction_safe in this case. +void* _ZGTtnaX (size_t) { return NULL; } +void _ZGTtdlPv (void*) { } +uint8_t _ITM_RU1(const uint8_t *) { return 0; } +uint32_t _ITM_RU4(const uint32_t *) { return 0; } +uint64_t _ITM_RU8(const uint64_t *) { return 0; } +void _ITM_memcpyRtWn(void *, const void *, size_t) { } +void _ITM_memcpyRnWt(void *, const void *, size_t) { } +void _ITM_addUserCommitAction(void (*)(void *), uint64_t, void *) { }; +#endif + +} + +// 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*), + "Pointers must be 32 bits or 64 bits wide"); +#if __UINTPTR_MAX__ == __UINT64_MAX__ + return (void*)_ITM_RU8((const uint64_t*)ptr); +#else + return (void*)_ITM_RU4((const uint32_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); +} + +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)); +} + +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 CTORDTORSTRINGCSTR(s) _txnal_sso_string_c_str((s)) +#else +#define CTORDTORSTRINGCSTR(s) "" +#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"))); \ +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), \ + CTORDTORSTRINGCSTR(&s), that); \ +} \ +void \ +_ZGTtNSt##NAME##C2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE( \ + CLASS*, const std::__sso_string&) __attribute__((alias \ +("_ZGTtNSt" #NAME \ + "C1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE"))); \ +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) + +} |