1 /* 2 * Copyright (C) 2008 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 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of 14 * its contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #ifndef Label_h 30 #define Label_h 31 32 #include "CodeBlock.h" 33 #include "Instruction.h" 34 #include <wtf/Assertions.h> 35 #include <wtf/Vector.h> 36 #include <limits.h> 37 38 namespace JSC { 39 40 class Label { 41 public: Label(CodeBlock * codeBlock)42 explicit Label(CodeBlock* codeBlock) 43 : m_refCount(0) 44 , m_location(invalidLocation) 45 , m_codeBlock(codeBlock) 46 { 47 } 48 setLocation(unsigned location)49 void setLocation(unsigned location) 50 { 51 m_location = location; 52 53 unsigned size = m_unresolvedJumps.size(); 54 for (unsigned i = 0; i < size; ++i) { 55 unsigned j = m_unresolvedJumps[i]; 56 m_codeBlock->instructions()[j].u.operand = m_location - j; 57 } 58 } 59 offsetFrom(int location)60 int offsetFrom(int location) const 61 { 62 if (m_location == invalidLocation) { 63 m_unresolvedJumps.append(location); 64 return 0; 65 } 66 return m_location - location; 67 } 68 ref()69 void ref() { ++m_refCount; } deref()70 void deref() 71 { 72 --m_refCount; 73 ASSERT(m_refCount >= 0); 74 } refCount()75 int refCount() const { return m_refCount; } 76 isForward()77 bool isForward() const { return m_location == invalidLocation; } 78 79 private: 80 typedef Vector<int, 8> JumpVector; 81 82 static const unsigned invalidLocation = UINT_MAX; 83 84 int m_refCount; 85 unsigned m_location; 86 CodeBlock* m_codeBlock; 87 mutable JumpVector m_unresolvedJumps; 88 }; 89 90 } // namespace JSC 91 92 #endif // Label_h 93