dfg/DFGNodeFlags.h

   1 /*
   2  * Copyright (C) 2012 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef DFGNodeFlags_h
  27 #define DFGNodeFlags_h
  28
  29 #include <wtf/Platform.h>
  30
  31 #if ENABLE(DFG_JIT)
  32
  33 #include <wtf/StdLibExtras.h>
  34
  35 namespace JSC { namespace DFG {
  36
  37 // Entries in the NodeType enum (below) are composed of an id, a result type (possibly none)
  38 // and some additional informative flags (must generate, is constant, etc).
  39 #define NodeResultMask              0xF
  40 #define NodeResultJS                0x1
  41 #define NodeResultNumber            0x2
  42 #define NodeResultInt32             0x3
  43 #define NodeResultBoolean           0x4
  44 #define NodeResultStorage           0x5
  45
  46 #define NodeMustGenerate           0x10 // set on nodes that have side effects, and may not trivially be removed by DCE.
  47 #define NodeHasVarArgs             0x20
  48 #define NodeClobbersWorld          0x40
  49 #define NodeMightClobber           0x80
  50
  51 #define NodeBehaviorMask          0x300
  52 #define NodeMayOverflow           0x100
  53 #define NodeMayNegZero            0x200
  54
  55 #define NodeBackPropMask         0x1C00
  56 #define NodeUseBottom             0x000
  57 #define NodeUsedAsNumber          0x400 // The result of this computation may be used in a context that observes fractional results.
  58 #define NodeNeedsNegZero          0x800 // The result of this computation may be used in a context that observes -0.
  59 #define NodeUsedAsValue           (NodeUsedAsNumber | NodeNeedsNegZero)
  60 #define NodeUsedAsInt            0x1000 // The result of this computation is known to be used in a context that prefers, but does not require, integer values.
  61
  62 typedef uint16_t NodeFlags;
  63
  64 static inline bool nodeUsedAsNumber(NodeFlags flags)
  65 {
  66     return !!(flags & NodeUsedAsNumber);
  67 }
  68
  69 static inline bool nodeCanTruncateInteger(NodeFlags flags)
  70 {
  71     return !nodeUsedAsNumber(flags);
  72 }
  73
  74 static inline bool nodeCanIgnoreNegativeZero(NodeFlags flags)
  75 {
  76     return !(flags & NodeNeedsNegZero);
  77 }
  78
  79 static inline bool nodeMayOverflow(NodeFlags flags)
  80 {
  81     return !!(flags & NodeMayOverflow);
  82 }
  83
  84 static inline bool nodeCanSpeculateInteger(NodeFlags flags)
  85 {
  86     if (flags & NodeMayOverflow)
  87         return !nodeUsedAsNumber(flags);
  88
  89     if (flags & NodeMayNegZero)
  90         return nodeCanIgnoreNegativeZero(flags);
  91
  92     return true;
  93 }
  94
  95 const char* nodeFlagsAsString(NodeFlags);
  96
  97 } } // namespace JSC::DFG
  98
  99 #endif // ENABLE(DFG_JIT)
 100
 101 #endif // DFGNodeFlags_h
 102