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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//
// This file implements the storage for the "Caught Exception Stack"
// https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html#cxx-exc-stack
//
//===----------------------------------------------------------------------===//
#include "cxa_exception.h"
#include <__threading_support>
#if defined(_LIBCXXABI_HAS_NO_THREADS)
namespace __cxxabiv1 {
extern "C" {
static __cxa_eh_globals eh_globals;
__cxa_eh_globals *__cxa_get_globals() { return &eh_globals; }
__cxa_eh_globals *__cxa_get_globals_fast() { return &eh_globals; }
} // extern "C"
} // namespace __cxxabiv1
#elif defined(HAS_THREAD_LOCAL)
namespace __cxxabiv1 {
namespace {
__cxa_eh_globals *__globals() {
static thread_local __cxa_eh_globals eh_globals;
return &eh_globals;
}
} // namespace
extern "C" {
__cxa_eh_globals *__cxa_get_globals() { return __globals(); }
__cxa_eh_globals *__cxa_get_globals_fast() { return __globals(); }
} // extern "C"
} // namespace __cxxabiv1
#else
#include "abort_message.h"
#include "fallback_malloc.h"
#if defined(__ELF__) && defined(_LIBCXXABI_LINK_PTHREAD_LIB)
#pragma comment(lib, "pthread")
#endif
// In general, we treat all threading errors as fatal.
// We cannot call std::terminate() because that will in turn
// call __cxa_get_globals() and cause infinite recursion.
namespace __cxxabiv1 {
namespace {
std::__libcpp_tls_key key_;
std::__libcpp_exec_once_flag flag_ = _LIBCPP_EXEC_ONCE_INITIALIZER;
void _LIBCPP_TLS_DESTRUCTOR_CC destruct_(void *p) {
__free_with_fallback(p);
if (0 != std::__libcpp_tls_set(key_, NULL))
abort_message("cannot zero out thread value for __cxa_get_globals()");
}
void construct_() {
if (0 != std::__libcpp_tls_create(&key_, destruct_))
abort_message("cannot create thread specific key for __cxa_get_globals()");
}
} // namespace
extern "C" {
__cxa_eh_globals *__cxa_get_globals() {
// Try to get the globals for this thread
__cxa_eh_globals *retVal = __cxa_get_globals_fast();
// If this is the first time we've been asked for these globals, create them
if (NULL == retVal) {
retVal = static_cast<__cxa_eh_globals*>(
__calloc_with_fallback(1, sizeof(__cxa_eh_globals)));
if (NULL == retVal)
abort_message("cannot allocate __cxa_eh_globals");
if (0 != std::__libcpp_tls_set(key_, retVal))
abort_message("std::__libcpp_tls_set failure in __cxa_get_globals()");
}
return retVal;
}
// Note that this implementation will reliably return NULL if not
// preceded by a call to __cxa_get_globals(). This is an extension
// to the Itanium ABI and is taken advantage of in several places in
// libc++abi.
__cxa_eh_globals *__cxa_get_globals_fast() {
// First time through, create the key.
if (0 != std::__libcpp_execute_once(&flag_, construct_))
abort_message("execute once failure in __cxa_get_globals_fast()");
return static_cast<__cxa_eh_globals*>(std::__libcpp_tls_get(key_));
}
} // extern "C"
} // namespace __cxxabiv1
#endif
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