1/* 2 * Copyright (c) 1994, 2003, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26package sun.tools.tree; 27 28import sun.tools.java.*; 29import sun.tools.asm.Assembler; 30import sun.tools.asm.Label; 31import java.io.PrintStream; 32import java.util.Hashtable; 33 34/** 35 * WARNING: The contents of this source file are not part of any 36 * supported API. Code that depends on them does so at its own risk: 37 * they are subject to change or removal without notice. 38 */ 39public 40class WhileStatement extends Statement { 41 Expression cond; 42 Statement body; 43 44 /** 45 * Constructor 46 */ 47 public WhileStatement(long where, Expression cond, Statement body) { 48 super(WHILE, where); 49 this.cond = cond; 50 this.body = body; 51 } 52 53 /** 54 * Check a while statement 55 */ 56 Vset check(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) { 57 checkLabel(env, ctx); 58 CheckContext newctx = new CheckContext(ctx, this); 59 // remember what was unassigned on entry 60 Vset vsEntry = vset.copy(); 61 // check the condition. Determine which variables have values if 62 // it returns true or false. 63 ConditionVars cvars = 64 cond.checkCondition(env, newctx, reach(env, vset), exp); 65 cond = convert(env, newctx, Type.tBoolean, cond); 66 // check the body, given that the condition returned true. 67 vset = body.check(env, newctx, cvars.vsTrue, exp); 68 vset = vset.join(newctx.vsContinue); 69 // make sure the back-branch fits the entry of the loop 70 ctx.checkBackBranch(env, this, vsEntry, vset); 71 // Exit the while loop by testing false or getting a break statement 72 vset = newctx.vsBreak.join(cvars.vsFalse); 73 return ctx.removeAdditionalVars(vset); 74 } 75 76 /** 77 * Inline 78 */ 79 public Statement inline(Environment env, Context ctx) { 80 ctx = new Context(ctx, this); 81 cond = cond.inlineValue(env, ctx); 82 if (body != null) { 83 body = body.inline(env, ctx); 84 } 85 return this; 86 } 87 88 /** 89 * The cost of inlining this statement 90 */ 91 public int costInline(int thresh, Environment env, Context ctx) { 92 return 1 + cond.costInline(thresh, env, ctx) 93 + ((body != null) ? body.costInline(thresh, env, ctx) : 0); 94 } 95 96 /** 97 * Create a copy of the statement for method inlining 98 */ 99 public Statement copyInline(Context ctx, boolean valNeeded) { 100 WhileStatement s = (WhileStatement)clone(); 101 s.cond = cond.copyInline(ctx); 102 if (body != null) { 103 s.body = body.copyInline(ctx, valNeeded); 104 } 105 return s; 106 } 107 108 /** 109 * Code 110 */ 111 public void code(Environment env, Context ctx, Assembler asm) { 112 CodeContext newctx = new CodeContext(ctx, this); 113 114 asm.add(where, opc_goto, newctx.contLabel); 115 116 Label l1 = new Label(); 117 asm.add(l1); 118 119 if (body != null) { 120 body.code(env, newctx, asm); 121 } 122 123 asm.add(newctx.contLabel); 124 cond.codeBranch(env, newctx, asm, l1, true); 125 asm.add(newctx.breakLabel); 126 } 127 128 /** 129 * Print 130 */ 131 public void print(PrintStream out, int indent) { 132 super.print(out, indent); 133 out.print("while "); 134 cond.print(out); 135 if (body != null) { 136 out.print(" "); 137 body.print(out, indent); 138 } else { 139 out.print(";"); 140 } 141 } 142} 143