Add atomic load/store, fetch_add, fence, and is-lock-free lowering.

src/IceIntrinsics.h

 //===- subzero/src/IceIntrinsics.h - List of Ice Intrinsics -----*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the kinds of intrinsics supported by PNaCl.
@@ skipping 36 matching lines @@
     Memmove,
     Memset,
     NaClReadTP,
     Setjmp,
     Sqrt,
     Stacksave,
     Stackrestore,
     Trap
   };
 
+  /// Operations that can be represented by the AtomicRMW
+  /// intrinsic.
+  ///
+  /// Do not reorder these values: their order offers forward
+  /// compatibility of bitcode targeted to PNaCl.
+  enum AtomicRMWOperation {
+    AtomicInvalid = 0, // Invalid, keep first.
+    AtomicAdd,
+    AtomicSub,
+    AtomicOr,
+    AtomicAnd,
+    AtomicXor,
+    AtomicExchange,
+    AtomicNum // Invalid, keep last.
+  };
+
+  /// Memory orderings supported by PNaCl IR.
+  ///
+  /// Do not reorder these values: their order offers forward
+  /// compatibility of bitcode targeted to PNaCl.
+  enum MemoryOrder {
+    MemoryOrderInvalid = 0, // Invalid, keep first.
+    MemoryOrderRelaxed,
+    MemoryOrderConsume,
+    MemoryOrderAcquire,
+    MemoryOrderRelease,
+    MemoryOrderAcquireRelease,
+    MemoryOrderSequentiallyConsistent,
+    MemoryOrderNum // Invalid, keep last.
+  };
+
+  static bool VerifyMemoryOrder(uint64_t Order);
+
   // Basic attributes related to each intrinsic, that are relevant to
   // code generation. We will want to have more attributes (e.g., Setjmp
   // returns twice and which affects stack coloring) once the lowering
   // cares about such attributes. Perhaps the attributes representation
   // can be shared with general function calls, though most functions
   // will be opaque.
   struct IntrinsicInfo {
     IntrinsicID ID : 31;
     bool HasSideEffects : 1;
   };
@@ skipping 18 matching lines @@
   typedef std::map<IceString, FullIntrinsicInfo> IntrinsicMap;
   IntrinsicMap map;
 
   Intrinsics(const Intrinsics &) LLVM_DELETED_FUNCTION;
   Intrinsics &operator=(const Intrinsics &) LLVM_DELETED_FUNCTION;
 };
 
 } // end of namespace Ice
 
 #endif // SUBZERO_SRC_ICEINTRINSICS_H