/*
* @(#)Statement.java 1.20 95/11/15 Arthur van Hoff
*
* Copyright (c) 1994 Sun Microsystems, Inc. All Rights Reserved.
*
* Permission to use, copy, modify, and distribute this software
* and its documentation for NON-COMMERCIAL purposes and without
* fee is hereby granted provided that this copyright notice
* appears in all copies. Please refer to the file "copyright.html"
* for further important copyright and licensing information.
*
* SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
* THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
* TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
* ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
* DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
package sun.tools.tree;
import sun.tools.java.*;
import sun.tools.asm.Assembler;
import sun.tools.asm.Label;
import java.io.PrintStream;
import java.util.Hashtable;
public
class Statement extends Node {
public static final long DEAD_END = (long)1 << 63;
Identifier labels[] = null;
/**
* Constructor
*/
Statement(int op, int where) {
super(op, where);
}
/**
* Set the label of a statement
*/
public void setLabel(Environment env, Expression e) {
if (e.op == IDENT) {
if (labels == null) {
labels = new Identifier[1];
} else {
// this should almost never happen. Multiple labels on
// the same statement. But handle it gracefully.
Identifier newLabels[] = new Identifier[labels.length + 1];
System.arraycopy(labels, 0, newLabels, 1, labels.length);
labels = newLabels;
}
labels[0] = ((IdentifierExpression)e).id;
} else {
env.error(e.where, "invalid.label");
}
}
/**
* Check a statement
*/
public long checkMethod(Environment env, Context ctx, long vset, Hashtable exp) {
vset = check(env, ctx, vset, exp);
// Check for return
if (!ctx.field.getType().getReturnType().isType(TC_VOID)) {
if ((vset & DEAD_END) == 0) {
env.error(ctx.field.getWhere(), "return.required.at.end", ctx.field);
}
}
return vset;
}
long checkDeclaration(Environment env, Context ctx, long vset, int mod, Type t, Hashtable exp) {
throw new CompilerError("checkDeclaration");
}
long check(Environment env, Context ctx, long vset, Hashtable exp) {
throw new CompilerError("check");
}
long reach(Environment env, long vset) {
if ((vset & DEAD_END) != 0) {
if (env.warnings()) {
env.error(where, "stat.not.reached");
}
vset &= ~DEAD_END;
}
return vset;
}
/**
* Inline
*/
public Statement inline(Environment env, Context ctx) {
return this;
}
/**
* Eliminate this statement, which is only possible if it has no label.
*/
public Statement eliminate(Environment env, Statement s) {
if ((s != null) && (labels != null)) {
Statement args[] = {s};
s = new CompoundStatement(where, args);
s.labels = labels;
}
return s;
}
/**
* Code
*/
public void code(Environment env, Context ctx, Assembler asm) {
throw new CompilerError("code");
}
/**
* Generate the code to call all finally's for a break, continue, or
* return statement. We must call "jsr" on all the cleanup code between
* the current context "ctx", and the destination context "stopctx".
* If 'save' isn't null, there is also a value on the top of the stack
*/
void codeFinally(Environment env, Context ctx, Assembler asm,
Context stopctx, Type save) {
Integer num = null;
boolean haveCleanup = false; // there is a finally or synchronize;
boolean haveNonLocalFinally = false; // some finally doesn't return;
for (Context c = ctx; (c != null) && (c != stopctx); c = c.prev) {
if (c.node == null)
continue;
if (c.node.op == SYNCHRONIZED) {
haveCleanup = true;
} else if (c.node.op == FINALLY) {
haveCleanup = true;
FinallyStatement st = ((FinallyStatement)(c.node));
if (!st.finallyFinishes) {
haveNonLocalFinally = true;
// after hitting a non-local finally, no need generating
// further code, because it won't get executed.
break;
}
}
}
if (!haveCleanup) {
// there is no cleanup that needs to be done. Just quit.
return;
}
if (save != null) {
// This statement has a return value on the stack.
ClassDefinition def = ctx.field.getClassDefinition();
if (!haveNonLocalFinally) {
// Save the return value in a register
LocalField lf = new LocalField(where, def, 0, save, null);
num = new Integer(ctx.declare(env, lf));
asm.add(where, opc_istore + save.getTypeCodeOffset(), num);
} else {
// Pop the return value.
switch(def.getType().getTypeCode()) {
case TC_VOID:
break;
case TC_DOUBLE: case TC_LONG:
asm.add(where, opc_pop2); break;
default:
asm.add(where, opc_pop); break;
}
}
}
// Call each of the cleanup functions, as necessary.
for (Context c = ctx ; (c != null) && (c != stopctx) ; c = c.prev) {
if (c.node == null)
continue;
if (c.node.op == SYNCHRONIZED) {
asm.add(where, opc_jsr, ((CodeContext)c).contLabel);
} else if (c.node.op == FINALLY) {
FinallyStatement st = ((FinallyStatement)(c.node));
Label label = ((CodeContext)c).contLabel;
if (st.finallyFinishes) {
asm.add(where, opc_jsr, label);
} else {
// the code never returns, so we're done.
asm.add(where, opc_goto, label);
break;
}
}
}
// Move the return value from the register back to the stack.
if (num != null) {
asm.add(where, opc_iload + save.getTypeCodeOffset(), num);
}
}
/*
* Return true if the statement has the given label
*/
public boolean hasLabel (Identifier lbl) {
Identifier labels[] = this.labels;
if (labels != null) {
for (int i = labels.length; --i >= 0; ) {
if (labels[i].equals(lbl)) {
return true;
}
}
}
return false;
}
/**
* Check if the first thing is a constructor invocation
*/
public boolean firstConstructor() {
return false;
}
/**
* Create a copy of the statement for method inlining
*/
public Statement copyInline(Context ctx, boolean valNeeded) {
return (Statement)clone();
}
/**
* The cost of inlining this statement
*/
public int costInline(int thresh) {
return thresh;
}
/**
* Print
*/
void printIndent(PrintStream out, int indent) {
for (int i = 0 ; i < indent ; i++) {
out.print(" ");
}
}
public void print(PrintStream out, int indent) {
if (labels != null) {
for (int i = labels.length; --i >= 0; )
out.print(labels[i] + ": ");
}
}
public void print(PrintStream out) {
print(out, 0);
}
}