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comparison graal/com.oracle.truffle.sl/src/com/oracle/truffle/sl/nodes/local/SLReadArgumentNode.java @ 13836:64c77f0577bb

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More documentation and improvements of Simple Language
author Christian Wimmer <christian.wimmer@oracle.com>
date Thu, 30 Jan 2014 17:53:27 -0800
parents b16ec83edc73
children afd6fa5e8229
comparison
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13835:67e4e7f56911 13836:64c77f0577bb
20 * or visit www.oracle.com if you need additional information or have any 20 * or visit www.oracle.com if you need additional information or have any
21 * questions. 21 * questions.
22 */ 22 */
23 package com.oracle.truffle.sl.nodes.local; 23 package com.oracle.truffle.sl.nodes.local;
24 24
25 import com.oracle.truffle.api.*;
25 import com.oracle.truffle.api.frame.*; 26 import com.oracle.truffle.api.frame.*;
26 import com.oracle.truffle.api.utilities.*; 27 import com.oracle.truffle.api.utilities.*;
27 import com.oracle.truffle.sl.nodes.*; 28 import com.oracle.truffle.sl.nodes.*;
29 import com.oracle.truffle.sl.parser.*;
28 import com.oracle.truffle.sl.runtime.*; 30 import com.oracle.truffle.sl.runtime.*;
29 31
32 /**
33 * Reads a function argument. Arguments are passed in as a {@link SLArguments} object, which
34 * encapsulates an {@link SLArguments#getFromFrame Object[] array}. Language-defined subclasses of
35 * {@link Arguments} are the standard Truffle way to pass values between function.
36 * <p>
37 * Arguments are not type-specialized. To ensure that repeated accesses within a method are
38 * specialized and can, e.g., accessed without unboxing, all arguments are loaded into local
39 * variables {@link SLNodeFactory#addFormalParameter in the method prologue}.
40 */
30 public class SLReadArgumentNode extends SLExpressionNode { 41 public class SLReadArgumentNode extends SLExpressionNode {
31 42
43 /** The argument number, i.e., the index into the array of arguments. */
32 private final int index; 44 private final int index;
33 45
46 /**
47 * Profiling information, collected by the interpreter, capturing whether the function was
48 * called with fewer actual arguments than formal arguments.
49 */
34 private final BranchProfile outOfBoundsTaken = new BranchProfile(); 50 private final BranchProfile outOfBoundsTaken = new BranchProfile();
35 51
36 public SLReadArgumentNode(int index) { 52 public SLReadArgumentNode(int index) {
37 this.index = index; 53 this.index = index;
38 } 54 }
41 public Object executeGeneric(VirtualFrame frame) { 57 public Object executeGeneric(VirtualFrame frame) {
42 Object[] args = SLArguments.getFromFrame(frame); 58 Object[] args = SLArguments.getFromFrame(frame);
43 if (index < args.length) { 59 if (index < args.length) {
44 return args[index]; 60 return args[index];
45 } else { 61 } else {
62 /* In the interpreter, record profiling information that the branch was used. */
46 outOfBoundsTaken.enter(); 63 outOfBoundsTaken.enter();
64 /* Use the default null value. */
47 return SLNull.SINGLETON; 65 return SLNull.SINGLETON;
48 } 66 }
49 } 67 }
50 } 68 }