39 lines
1.3 KiB
Diff
39 lines
1.3 KiB
Diff
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From ff00346174831ec01bc6b85c39c19d502cfa2093 Mon Sep 17 00:00:00 2001
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From: Brian Cain <bcain@quicinc.com>
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Date: Thu, 27 Jan 2022 08:09:11 -0800
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Subject: [PATCH 2/2] Omit atomic_{,un}signed_lock_free if unsupported
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On targets that have limited atomic support, e.g. ones that define
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ATOMIC_*_LOCK_FREE to '1' ("sometimes lock free"), we would end up
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referencing yet-undefined __libcpp_{,un}signed_lock_free.
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This commit adds a guard to prevent these references for such
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targets.
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Differential Revision: https://reviews.llvm.org/D118391
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---
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libcxx/include/atomic | 3 +++
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1 file changed, 3 insertions(+)
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diff --git a/libcxx/include/atomic b/libcxx/include/atomic
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index 0fc799a24319..57d01ad2791a 100644
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--- a/libcxx/include/atomic
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+++ b/libcxx/include/atomic
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@@ -2791,10 +2791,13 @@ typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, char>::typ
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typedef conditional<_LIBCPP_CONTENTION_LOCK_FREE, __cxx_contention_t, unsigned char>::type __libcpp_unsigned_lock_free;
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#else
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// No signed/unsigned lock-free types
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+#define _LIBCPP_NO_LOCK_FREE_TYPES
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#endif
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+#if !defined(_LIBCPP_NO_LOCK_FREE_TYPES)
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typedef atomic<__libcpp_signed_lock_free> atomic_signed_lock_free;
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typedef atomic<__libcpp_unsigned_lock_free> atomic_unsigned_lock_free;
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+#endif
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#define ATOMIC_FLAG_INIT {false}
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#define ATOMIC_VAR_INIT(__v) {__v}
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--
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2.32.0
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