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package sun.tools.tree;

import sun.tools.java.*;
import sun.tools.asm.Assembler;
import sun.tools.asm.Label;
import sun.tools.asm.TryData;
import sun.tools.asm.CatchData;
import java.io.PrintStream;
import java.util.Hashtable;
import java.util.Enumeration;

WARNING: The contents of this source file are not part of any supported API. Code that depends on them does so at its own risk: they are subject to change or removal without notice.
/** * WARNING: The contents of this source file are not part of any * supported API. Code that depends on them does so at its own risk: * they are subject to change or removal without notice. */
public class FinallyStatement extends Statement { Statement body; Statement finalbody; boolean finallyCanFinish; // does finalBody never return? boolean needReturnSlot; // set by inner return statement Statement init; // try object expression or declaration from parser LocalMember tryTemp; // temp holding the try object, if any
Constructor
/** * Constructor */
public FinallyStatement(long where, Statement body, Statement finalbody) { super(FINALLY, where); this.body = body; this.finalbody = finalbody; } // /** // * Constructor for try (init) {body} // */ // public FinallyStatement(long where, Statement init, Statement body, int junk) { // this(where, body, null); // this.init = init; // }
Check statement
/** * Check statement */
Vset check(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp) { vset = reach(env, vset); Hashtable<Object, Object> newexp = new Hashtable<>(); // Handle the proposed 'try (init) { stmts } finally { stmts }' syntax. // This feature has not been adopted, and support is presently disabled. /*-----------------------------------------------------------* if (init != null) { ClassDefinition sourceClass = ctx.field.getClassDefinition(); Expression tryExpr = null; DeclarationStatement tryDecl = null; long where = init.getWhere(); // find out whether init is a simple expression or a declaration if (init.getOp() == EXPRESSION) { tryExpr = ((ExpressionStatement)init).expr; init = null; // restore it below vset = tryExpr.checkValue(env, ctx, vset, exp); } else if (init.getOp() == DECLARATION) { tryDecl = (DeclarationStatement) init; init = null; // restore it below vset = tryDecl.checkBlockStatement(env, ctx, vset, exp); if (tryDecl.args.length != 1) { env.error(where, "invalid.decl"); } else { LocalMember field = ((VarDeclarationStatement) tryDecl.args[0]).field; tryExpr = new IdentifierExpression(where, field); tryExpr.type = field.getType(); } } else { env.error(where, "invalid.expr"); vset = init.check(env, ctx, vset, exp); } Type type = (tryExpr == null) ? Type.tError : tryExpr.getType(); MemberDefinition tryEnter = null; MemberDefinition tryExit = null; if (!type.isType(TC_CLASS)) { if (!type.isType(TC_ERROR)) { env.error(where, "invalid.method.invoke", type); } } else { Identifier idTryEnter = Identifier.lookup("tryEnter"); Identifier idTryExit = Identifier.lookup("tryExit"); Type tTryMethod = Type.tMethod(Type.tVoid); try { ClassDefinition tryClass = env.getClassDefinition(type); tryEnter = tryClass.matchMethod(env, sourceClass, idTryEnter); tryExit = tryClass.matchMethod(env, sourceClass, idTryExit); if (tryEnter != null && !tryEnter.getType().equals(tTryMethod)) { tryEnter = null; } if (tryExit != null && !tryExit.getType().equals(tTryMethod)) { tryExit = null; } } catch (ClassNotFound ee) { env.error(where, "class.not.found", ee.name, ctx.field); } catch (AmbiguousMember ee) { Identifier id = ee.field1.getName(); env.error(where, "ambig.field", id, ee.field1, ee.field2); } } if (tryEnter == null || tryExit == null) { // Make a better (more didactic) error here! env.error(where, "invalid.method.invoke", type); } else { tryTemp = new LocalMember(where, sourceClass, 0, type, Identifier.lookup("<try_object>")); ctx = new Context(ctx, this); ctx.declare(env, tryTemp); Expression e; e = new IdentifierExpression(where, tryTemp); e = new AssignExpression(where, e, tryExpr); e = new MethodExpression(where, e, tryEnter, new Expression[0]); e.type = Type.tVoid; Statement enterCall = new ExpressionStatement(where, e); // store it on the init, for code generation if (tryDecl != null) { Statement args2[] = { tryDecl.args[0], enterCall }; tryDecl.args = args2; init = tryDecl; } else { init = enterCall; } e = new IdentifierExpression(where, tryTemp); e = new MethodExpression(where, e, tryExit, new Expression[0]); e.type = Type.tVoid; Statement exitCall = new ExpressionStatement(where, e); finalbody = exitCall; } } *-----------------------------------------------------------*/ // Check the try part. We reach the end of the try part either by // finishing normally, or doing a break to the label of the try/finally. // NOTE: I don't think newctx1.vsBreak is ever used -- see TryStatement. CheckContext newctx1 = new CheckContext(ctx, this); Vset vset1 = body.check(env, newctx1, vset.copy(), newexp) .join(newctx1.vsBreak); // Check the finally part. CheckContext newctx2 = new CheckContext(ctx, this); // Should never access this field. The null indicates the finally part. newctx2.vsContinue = null; Vset vset2 = finalbody.check(env, newctx2, vset, exp); finallyCanFinish = !vset2.isDeadEnd(); vset2 = vset2.join(newctx2.vsBreak); // If !finallyCanFinish, then the only possible exceptions that can // occur at this point are the ones preceding the try/finally, or // the ones generated by the finally. Anything in the try is // irrelevant. Otherwise, we have to merge in all the exceptions // generated by the body into exp. if (finallyCanFinish) { // Add newexp's back into exp; cf. ThrowStatement.check(). for (Enumeration<?> e = newexp.keys() ; e.hasMoreElements() ; ) { Object def = e.nextElement(); exp.put(def, newexp.get(def)); } } return ctx.removeAdditionalVars(vset1.addDAandJoinDU(vset2)); }
Inline
/** * Inline */
public Statement inline(Environment env, Context ctx) { if (tryTemp != null) { ctx = new Context(ctx, this); ctx.declare(env, tryTemp); } if (init != null) { init = init.inline(env, ctx); } if (body != null) { body = body.inline(env, ctx); } if (finalbody != null) { finalbody = finalbody.inline(env, ctx); } if (body == null) { return eliminate(env, finalbody); } if (finalbody == null) { return eliminate(env, body); } return this; }
Create a copy of the statement for method inlining
/** * Create a copy of the statement for method inlining */
public Statement copyInline(Context ctx, boolean valNeeded) { FinallyStatement s = (FinallyStatement)clone(); if (tryTemp != null) { s.tryTemp = tryTemp.copyInline(ctx); } if (init != null) { s.init = init.copyInline(ctx, valNeeded); } if (body != null) { s.body = body.copyInline(ctx, valNeeded); } if (finalbody != null) { s.finalbody = finalbody.copyInline(ctx, valNeeded); } return s; }
Compute cost of inlining this statement
/** * Compute cost of inlining this statement */
public int costInline(int thresh, Environment env, Context ctx){ int cost = 4; if (init != null) { cost += init.costInline(thresh, env,ctx); if (cost >= thresh) return cost; } if (body != null) { cost += body.costInline(thresh, env,ctx); if (cost >= thresh) return cost; } if (finalbody != null) { cost += finalbody.costInline(thresh, env,ctx); } return cost; }
Code
/** * Code */
public void code(Environment env, Context ctx, Assembler asm) { ctx = new Context(ctx); Integer num1 = null, num2 = null; Label endLabel = new Label(); if (tryTemp != null) { ctx.declare(env, tryTemp); } if (init != null) { CodeContext exprctx = new CodeContext(ctx, this); init.code(env, exprctx, asm); } if (finallyCanFinish) { LocalMember f1, f2; ClassDefinition thisClass = ctx.field.getClassDefinition(); if (needReturnSlot) { Type returnType = ctx.field.getType().getReturnType(); LocalMember localfield = new LocalMember(0, thisClass, 0, returnType, idFinallyReturnValue); ctx.declare(env, localfield); Environment.debugOutput("Assigning return slot to " + localfield.number); } // allocate space for the exception and return address f1 = new LocalMember(where, thisClass, 0, Type.tObject, null); f2 = new LocalMember(where, thisClass, 0, Type.tInt, null); num1 = ctx.declare(env, f1); num2 = ctx.declare(env, f2); } TryData td = new TryData(); td.add(null); // Main body CodeContext bodyctx = new CodeContext(ctx, this); asm.add(where, opc_try, td); // start of protected code body.code(env, bodyctx, asm); asm.add(bodyctx.breakLabel); asm.add(td.getEndLabel()); // end of protected code // Cleanup afer body if (finallyCanFinish) { asm.add(where, opc_jsr, bodyctx.contLabel); asm.add(where, opc_goto, endLabel); } else { // just goto the cleanup code. It will never return. asm.add(where, opc_goto, bodyctx.contLabel); } // Catch code CatchData cd = td.getCatch(0); asm.add(cd.getLabel()); if (finallyCanFinish) { asm.add(where, opc_astore, num1); // store exception asm.add(where, opc_jsr, bodyctx.contLabel); asm.add(where, opc_aload, num1); // rethrow exception asm.add(where, opc_athrow); } else { // pop exception off stack. Fall through to finally code asm.add(where, opc_pop); } // The finally part, which is marked by the contLabel. Update // breakLabel: since break's in the finally are different // contLabel: to null to indicate no longer in the protected code. asm.add(bodyctx.contLabel); bodyctx.contLabel = null; bodyctx.breakLabel = endLabel; if (finallyCanFinish) { asm.add(where, opc_astore, num2); // save the return address finalbody.code(env, bodyctx, asm); // execute the cleanup code asm.add(where, opc_ret, num2); // return } else { finalbody.code(env, bodyctx, asm); // execute the cleanup code } asm.add(endLabel); // breaks come here }
Print
/** * Print */
public void print(PrintStream out, int indent) { super.print(out, indent); out.print("try "); if (body != null) { body.print(out, indent); } else { out.print("<empty>"); } out.print(" finally "); if (finalbody != null) { finalbody.print(out, indent); } else { out.print("<empty>"); } } }