vendor/llvm/llvm-release_39-r276489

1 files changed, 153 insertions, 0 deletions

diff --git a/include/llvm/Support/AtomicOrdering.h b/include/llvm/Support/AtomicOrdering.h
new file mode 100644
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+++ b/include/llvm/Support/AtomicOrdering.h
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+//===-- llvm/Support/AtomicOrdering.h ---Atomic Ordering---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief Atomic ordering constants.
+///
+/// These values are used by LLVM to represent atomic ordering for C++11's
+/// memory model and more, as detailed in docs/Atomics.rst.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_ATOMICORDERING_H
+#define LLVM_SUPPORT_ATOMICORDERING_H
+
+#include <cstddef>
+
+namespace llvm {
+
+/// Atomic ordering for C11 / C++11's memody models.
+///
+/// These values cannot change because they are shared with standard library
+/// implementations as well as with other compilers.
+enum class AtomicOrderingCABI {
+  relaxed = 0,
+  consume = 1,
+  acquire = 2,
+  release = 3,
+  acq_rel = 4,
+  seq_cst = 5,
+};
+
+bool operator<(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
+bool operator>(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
+bool operator<=(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
+bool operator>=(AtomicOrderingCABI, AtomicOrderingCABI) = delete;
+
+// Validate an integral value which isn't known to fit within the enum's range
+// is a valid AtomicOrderingCABI.
+template <typename Int> static inline bool isValidAtomicOrderingCABI(Int I) {
+  return (Int)AtomicOrderingCABI::relaxed <= I &&
+         I <= (Int)AtomicOrderingCABI::seq_cst;
+}
+
+/// Atomic ordering for LLVM's memory model.
+///
+/// C++ defines ordering as a lattice. LLVM supplements this with NotAtomic and
+/// Unordered, which are both below the C++ orders.
+///
+/// not_atomic-->unordered-->relaxed-->release--------------->acq_rel-->seq_cst
+///                                   \-->consume-->acquire--/
+enum class AtomicOrdering {
+  NotAtomic = 0,
+  Unordered = 1,
+  Monotonic = 2, // Equivalent to C++'s relaxed.
+  // Consume = 3,  // Not specified yet.
+  Acquire = 4,
+  Release = 5,
+  AcquireRelease = 6,
+  SequentiallyConsistent = 7
+};
+
+bool operator<(AtomicOrdering, AtomicOrdering) = delete;
+bool operator>(AtomicOrdering, AtomicOrdering) = delete;
+bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
+bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
+
+// Validate an integral value which isn't known to fit within the enum's range
+// is a valid AtomicOrdering.
+template <typename Int> static inline bool isValidAtomicOrdering(Int I) {
+  return (Int)AtomicOrdering::NotAtomic <= I &&
+         I <= (Int)AtomicOrdering::SequentiallyConsistent;
+}
+
+/// String used by LLVM IR to represent atomic ordering.
+static inline const char *toIRString(AtomicOrdering ao) {
+  static const char *names[8] = {"not_atomic", "unordered", "monotonic",
+                                 "consume",    "acquire",   "release",
+                                 "acq_rel",    "seq_cst"};
+  return names[(size_t)ao];
+}
+
+/// Returns true if ao is stronger than other as defined by the AtomicOrdering
+/// lattice, which is based on C++'s definition.
+static inline bool isStrongerThan(AtomicOrdering ao, AtomicOrdering other) {
+  static const bool lookup[8][8] = {
+      //               NA UN RX CO AC RE AR SC
+      /* NotAtomic */ {0, 0, 0, 0, 0, 0, 0, 0},
+      /* Unordered */ {1, 0, 0, 0, 0, 0, 0, 0},
+      /* relaxed   */ {1, 1, 0, 0, 0, 0, 0, 0},
+      /* consume   */ {1, 1, 1, 0, 0, 0, 0, 0},
+      /* acquire   */ {1, 1, 1, 1, 0, 0, 0, 0},
+      /* release   */ {1, 1, 1, 0, 0, 0, 0, 0},
+      /* acq_rel   */ {1, 1, 1, 1, 1, 1, 0, 0},
+      /* seq_cst   */ {1, 1, 1, 1, 1, 1, 1, 0},
+  };
+  return lookup[(size_t)ao][(size_t)other];
+}
+
+static inline bool isAtLeastOrStrongerThan(AtomicOrdering ao,
+                                           AtomicOrdering other) {
+  static const bool lookup[8][8] = {
+      //               NA UN RX CO AC RE AR SC
+      /* NotAtomic */ {1, 0, 0, 0, 0, 0, 0, 0},
+      /* Unordered */ {1, 1, 0, 0, 0, 0, 0, 0},
+      /* relaxed   */ {1, 1, 1, 0, 0, 0, 0, 0},
+      /* consume   */ {1, 1, 1, 1, 0, 0, 0, 0},
+      /* acquire   */ {1, 1, 1, 1, 1, 0, 0, 0},
+      /* release   */ {1, 1, 1, 0, 0, 1, 0, 0},
+      /* acq_rel   */ {1, 1, 1, 1, 1, 1, 1, 0},
+      /* seq_cst   */ {1, 1, 1, 1, 1, 1, 1, 1},
+  };
+  return lookup[(size_t)ao][(size_t)other];
+}
+
+static inline bool isStrongerThanUnordered(AtomicOrdering ao) {
+  return isStrongerThan(ao, AtomicOrdering::Unordered);
+}
+
+static inline bool isStrongerThanMonotonic(AtomicOrdering ao) {
+  return isStrongerThan(ao, AtomicOrdering::Monotonic);
+}
+
+static inline bool isAcquireOrStronger(AtomicOrdering ao) {
+  return isAtLeastOrStrongerThan(ao, AtomicOrdering::Acquire);
+}
+
+static inline bool isReleaseOrStronger(AtomicOrdering ao) {
+  return isAtLeastOrStrongerThan(ao, AtomicOrdering::Release);
+}
+
+static inline AtomicOrderingCABI toCABI(AtomicOrdering ao) {
+  static const AtomicOrderingCABI lookup[8] = {
+      /* NotAtomic */ AtomicOrderingCABI::relaxed,
+      /* Unordered */ AtomicOrderingCABI::relaxed,
+      /* relaxed   */ AtomicOrderingCABI::relaxed,
+      /* consume   */ AtomicOrderingCABI::consume,
+      /* acquire   */ AtomicOrderingCABI::acquire,
+      /* release   */ AtomicOrderingCABI::release,
+      /* acq_rel   */ AtomicOrderingCABI::acq_rel,
+      /* seq_cst   */ AtomicOrderingCABI::seq_cst,
+  };
+  return lookup[(size_t)ao];
+}
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_ATOMICORDERING_H