JavaScriptCore-1097.3.tar.gz

[apple/javascriptcore.git] / dfg / DFGNodeFlags.h

diff --git a/dfg/DFGNodeFlags.h b/dfg/DFGNodeFlags.h
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+/*
+ * Copyright (C) 2012 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#ifndef DFGNodeFlags_h
+#define DFGNodeFlags_h
+
+#include <wtf/Platform.h>
+
+#if ENABLE(DFG_JIT)
+
+#include <wtf/StdLibExtras.h>
+
+namespace JSC { namespace DFG {
+
+// Entries in the NodeType enum (below) are composed of an id, a result type (possibly none)
+// and some additional informative flags (must generate, is constant, etc).
+#define NodeResultMask              0xF
+#define NodeResultJS                0x1
+#define NodeResultNumber            0x2
+#define NodeResultInt32             0x3
+#define NodeResultBoolean           0x4
+#define NodeResultStorage           0x5
+                                
+#define NodeMustGenerate           0x10 // set on nodes that have side effects, and may not trivially be removed by DCE.
+#define NodeHasVarArgs             0x20
+#define NodeClobbersWorld          0x40
+#define NodeMightClobber           0x80
+                                
+#define NodeBehaviorMask          0x300
+#define NodeMayOverflow           0x100
+#define NodeMayNegZero            0x200
+                                
+#define NodeBackPropMask         0x1C00
+#define NodeUseBottom             0x000
+#define NodeUsedAsNumber          0x400 // The result of this computation may be used in a context that observes fractional results.
+#define NodeNeedsNegZero          0x800 // The result of this computation may be used in a context that observes -0.
+#define NodeUsedAsValue           (NodeUsedAsNumber | NodeNeedsNegZero)
+#define NodeUsedAsInt            0x1000 // The result of this computation is known to be used in a context that prefers, but does not require, integer values.
+
+typedef uint16_t NodeFlags;
+
+static inline bool nodeUsedAsNumber(NodeFlags flags)
+{
+    return !!(flags & NodeUsedAsNumber);
+}
+
+static inline bool nodeCanTruncateInteger(NodeFlags flags)
+{
+    return !nodeUsedAsNumber(flags);
+}
+
+static inline bool nodeCanIgnoreNegativeZero(NodeFlags flags)
+{
+    return !(flags & NodeNeedsNegZero);
+}
+
+static inline bool nodeMayOverflow(NodeFlags flags)
+{
+    return !!(flags & NodeMayOverflow);
+}
+
+static inline bool nodeCanSpeculateInteger(NodeFlags flags)
+{
+    if (flags & NodeMayOverflow)
+        return !nodeUsedAsNumber(flags);
+    
+    if (flags & NodeMayNegZero)
+        return nodeCanIgnoreNegativeZero(flags);
+    
+    return true;
+}
+
+const char* nodeFlagsAsString(NodeFlags);
+
+} } // namespace JSC::DFG
+
+#endif // ENABLE(DFG_JIT)
+
+#endif // DFGNodeFlags_h
+