commit d39de4792dbdb6ab5f78c79d52d0210b44584538
author Kirill A. Korinsky <kirill@korins.ky> Thu Apr 07 15:07:37 2022 +0200
committer Tomas Mraz <tomas@openssl.org> Fri Apr 22 15:25:20 2022 +0200
tree 99065181d1ae6abd6fa6c8e24bebe7a1eb202f98
parent c29cf39449f78008e39af8f83760f2464815248b

Never use `__atomic_*` on macOS 10.7 and 10.8

macOS 10.7 and 10.8 had a bit wired clang which is detected as
`__GNUC__` which has `__ATOMIC_ACQ_REL` but it excepts one option at
`__atomic_is_lock_free` instead of 2.

This prevents OpenSSL to be compiled on such systems.

Fixes: #18055

Signed-off-by: Kirill A. Korinsky <kirill@korins.ky>

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/18056)

crypto/threads_pthread.c

diff --git a/crypto/threads_pthread.c b/crypto/threads_pthread.c
index 2b7280c..46b8459 100644
--- a/crypto/threads_pthread.c
+++ b/crypto/threads_pthread.c
@@ -17,6 +17,18 @@
 # include <atomic.h>
 #endif
 
+#if defined(__apple_build_version__) && __apple_build_version__ < 6000000
+/*
+ * OS/X 10.7 and 10.8 had a weird version of clang which has __ATOMIC_ACQUIRE and
+ * __ATOMIC_ACQ_REL but which expects only one parameter for __atomic_is_lock_free()
+ * rather than two which has signature __atomic_is_lock_free(sizeof(_Atomic(T))).
+ * All of this makes impossible to use __atomic_is_lock_free here.
+ *
+ * See: https://github.com/llvm/llvm-project/commit/a4c2602b714e6c6edb98164550a5ae829b2de760
+ */
+#define BROKEN_CLANG_ATOMICS
+#endif
+
 #if defined(OPENSSL_THREADS) && !defined(CRYPTO_TDEBUG) && !defined(OPENSSL_SYS_WINDOWS)
 
 # if defined(OPENSSL_SYS_UNIX)
@@ -188,7 +200,7 @@
 
 int CRYPTO_atomic_add(int *val, int amount, int *ret, CRYPTO_RWLOCK *lock)
 {
-# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL)
+# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS)
     if (__atomic_is_lock_free(sizeof(*val), val)) {
         *ret = __atomic_add_fetch(val, amount, __ATOMIC_ACQ_REL);
         return 1;
@@ -215,7 +227,7 @@
 int CRYPTO_atomic_or(uint64_t *val, uint64_t op, uint64_t *ret,
                      CRYPTO_RWLOCK *lock)
 {
-# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL)
+# if defined(__GNUC__) && defined(__ATOMIC_ACQ_REL) && !defined(BROKEN_CLANG_ATOMICS)
     if (__atomic_is_lock_free(sizeof(*val), val)) {
         *ret = __atomic_or_fetch(val, op, __ATOMIC_ACQ_REL);
         return 1;
@@ -240,7 +252,7 @@
 
 int CRYPTO_atomic_load(uint64_t *val, uint64_t *ret, CRYPTO_RWLOCK *lock)
 {
-# if defined(__GNUC__) && defined(__ATOMIC_ACQUIRE)
+# if defined(__GNUC__) && defined(__ATOMIC_ACQUIRE) && !defined(BROKEN_CLANG_ATOMICS)
     if (__atomic_is_lock_free(sizeof(*val), val)) {
         __atomic_load(val, ret, __ATOMIC_ACQUIRE);
         return 1;