[libcxxabi] Always use thread_local for cxa_exception_storage
This was previously guarded by HAS_THREAD_LOCAL, which was never set by
CMake and had to be specified manually. Android has been setting this to
solve https://github.com/android/ndk/issues/1200 [1], but every compiler
and platform libc++abi supports should have thread_local by now, so we
can just get rid of the fallback implementation and simplify things
significantly (including removing the now unused fallback calloc).
[1] https://android-review.googlesource.com/c/toolchain/llvm-project/+/1285596
Reviewed By: #libc_abi, MaskRay, ldionne
Differential Revision: https://reviews.llvm.org/D138461
NOKEYCHECK=True
GitOrigin-RevId: 8271aa5335668a1dc62168a4e90b4554bd3a0ca7
diff --git a/src/cxa_exception_storage.cpp b/src/cxa_exception_storage.cpp
index 3a3233a..1abf614 100644
--- a/src/cxa_exception_storage.cpp
+++ b/src/cxa_exception_storage.cpp
@@ -12,21 +12,18 @@
#include "cxa_exception.h"
-#include <__threading_support>
+namespace __cxxabiv1 {
#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)
+#else
-namespace __cxxabiv1 {
namespace {
__cxa_eh_globals *__globals() {
static thread_local __cxa_eh_globals eh_globals;
@@ -38,66 +35,7 @@
__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
+
+} // namespace __cxxabiv1
diff --git a/src/fallback_malloc.cpp b/src/fallback_malloc.cpp
index 591efbe..759bb58 100644
--- a/src/fallback_malloc.cpp
+++ b/src/fallback_malloc.cpp
@@ -270,17 +270,6 @@
return fallback_malloc(size);
}
-void* __calloc_with_fallback(size_t count, size_t size) {
- void* ptr = ::calloc(count, size);
- if (NULL != ptr)
- return ptr;
- // if calloc fails, fall back to emergency stash
- ptr = fallback_malloc(size * count);
- if (NULL != ptr)
- ::memset(ptr, 0, size * count);
- return ptr;
-}
-
void __aligned_free_with_fallback(void* ptr) {
if (is_fallback_ptr(ptr))
fallback_free(ptr);
diff --git a/src/fallback_malloc.h b/src/fallback_malloc.h
index 816e691..528014b 100644
--- a/src/fallback_malloc.h
+++ b/src/fallback_malloc.h
@@ -17,9 +17,6 @@
// Allocate some memory from _somewhere_
_LIBCXXABI_HIDDEN void * __aligned_malloc_with_fallback(size_t size);
-// Allocate and zero-initialize memory from _somewhere_
-_LIBCXXABI_HIDDEN void * __calloc_with_fallback(size_t count, size_t size);
-
_LIBCXXABI_HIDDEN void __aligned_free_with_fallback(void *ptr);
_LIBCXXABI_HIDDEN void __free_with_fallback(void *ptr);