[apple/javascriptcore.git] / dfg / DFGMayExit.cpp

/*
 * Copyright (C) 2014, 2015 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. 
 */

#include "config.h"
#include "DFGMayExit.h"

#if ENABLE(DFG_JIT)

#include "DFGGraph.h"
#include "DFGNode.h"
#include "Operations.h"

namespace JSC { namespace DFG {

namespace {

class EdgeMayExit {
public:
    EdgeMayExit()
        : m_result(false)
    {
    }
    
    void operator()(Node*, Edge edge)
    {
        if (edge.willHaveCheck()) {
            m_result = true;
            return;
        }

        switch (edge.useKind()) {
        // These are shady because nodes that have these use kinds will typically exit for
        // unrelated reasons. For example CompareEq doesn't usually exit, but if it uses ObjectUse
        // then it will.
        case ObjectUse:
        case ObjectOrOtherUse:
            m_result = true;
            break;
            
        // These are shady because they check the structure even if the type of the child node
        // passes the StringObject type filter.
        case StringObjectUse:
        case StringOrStringObjectUse:
            m_result = true;
            break;
            
        default:
            break;
        }
    }
    
    bool result() const { return m_result; }
    
private:
    bool m_result;
};

} // anonymous namespace

bool mayExit(Graph& graph, Node* node)
{
    switch (node->op()) {
    // This is a carefully curated list of nodes that definitely do not exit. We try to be very
    // conservative when maintaining this list, because adding new node types to it doesn't
    // generally make things a lot better but it might introduce insanely subtle bugs.
    case SetArgument:
    case JSConstant:
    case DoubleConstant:
    case Int52Constant:
    case MovHint:
    case SetLocal:
    case Flush:
    case Phantom:
    case Check:
    case GetLocal:
    case LoopHint:
    case Phi:
    case Upsilon:
    case ZombieHint:
    case BottomValue:
    case PutHint:
    case PhantomNewObject:
    case PutStack:
    case KillStack:
    case GetStack:
    case GetCallee:
    case GetArgumentCount:
    case GetScope:
    case PhantomLocal:
    case CountExecution:
    case Jump:
    case Branch:
    case Unreachable:
    case DoubleRep:
    case Int52Rep:
    case ValueRep:
        break;
        
    default:
        // If in doubt, return true.
        return true;
    }

    EdgeMayExit functor;
    DFG_NODE_DO_TO_CHILDREN(graph, node, functor);
    return functor.result();
}

} } // namespace JSC::DFG

#endif // ENABLE(DFG_JIT)
Commit	Line	Data
ed1e77d3 A	1	/*
	2	* Copyright (C) 2014, 2015 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	#include "config.h"
	27	#include "DFGMayExit.h"
	28
	29	#if ENABLE(DFG_JIT)
	30
	31	#include "DFGGraph.h"
	32	#include "DFGNode.h"
	33	#include "Operations.h"
	34
	35	namespace JSC { namespace DFG {
	36
	37	namespace {
	38
	39	class EdgeMayExit {
	40	public:
	41	EdgeMayExit()
	42	: m_result(false)
	43	{
	44	}
	45
	46	void operator()(Node*, Edge edge)
	47	{
	48	if (edge.willHaveCheck()) {
	49	m_result = true;
	50	return;
	51	}
	52
	53	switch (edge.useKind()) {
	54	// These are shady because nodes that have these use kinds will typically exit for
	55	// unrelated reasons. For example CompareEq doesn't usually exit, but if it uses ObjectUse
	56	// then it will.
	57	case ObjectUse:
	58	case ObjectOrOtherUse:
	59	m_result = true;
	60	break;
	61
	62	// These are shady because they check the structure even if the type of the child node
	63	// passes the StringObject type filter.
	64	case StringObjectUse:
65	case StringOrStringObjectUse:
66	m_result = true;
67	break;
68
69	default:
70	break;
71	}
72	}
73
74	bool result() const { return m_result; }
75
76	private:
77	bool m_result;
78	};
79
80	} // anonymous namespace
81
82	bool mayExit(Graph& graph, Node* node)
83	{
84	switch (node->op()) {
85	// This is a carefully curated list of nodes that definitely do not exit. We try to be very
86	// conservative when maintaining this list, because adding new node types to it doesn't
87	// generally make things a lot better but it might introduce insanely subtle bugs.
88	case SetArgument:
89	case JSConstant:
90	case DoubleConstant:
91	case Int52Constant:
92	case MovHint:
93	case SetLocal:
94	case Flush:
95	case Phantom:
96	case Check:
97	case GetLocal:
98	case LoopHint:
99	case Phi:
100	case Upsilon:
101	case ZombieHint:
102	case BottomValue:
103	case PutHint:
104	case PhantomNewObject:
105	case PutStack:
106	case KillStack:
107	case GetStack:
108	case GetCallee:
109	case GetArgumentCount:
110	case GetScope:
111	case PhantomLocal:
112	case CountExecution:
113	case Jump:
114	case Branch:
115	case Unreachable:
116	case DoubleRep:
117	case Int52Rep:
118	case ValueRep:
119	break;
120
121	default:
122	// If in doubt, return true.
123	return true;
124	}
125
126	EdgeMayExit functor;
127	DFG_NODE_DO_TO_CHILDREN(graph, node, functor);
128	return functor.result();
129	}
130
131	} } // namespace JSC::DFG
132
133	#endif // ENABLE(DFG_JIT)