1 package serp.bytecode;
2
3 import java.io.*;
4 import java.util.*;
5
6 import serp.bytecode.visitor.*;
7
8 /***
9 * Returns a value (or void) from a method.
10 *
11 * @author Abe White
12 */
13 public class ReturnInstruction extends TypedInstruction {
14 private static final Class[][] _mappings = new Class[][] {
15 { byte.class, int.class },
16 { char.class, int.class },
17 { short.class, int.class },
18 { boolean.class, int.class },
19 };
20
21 ReturnInstruction(Code owner) {
22 super(owner);
23 }
24
25 ReturnInstruction(Code owner, int opcode) {
26 super(owner, opcode);
27 }
28
29 public String getTypeName() {
30 switch (getOpcode()) {
31 case Constants.IRETURN:
32 return int.class.getName();
33 case Constants.LRETURN:
34 return long.class.getName();
35 case Constants.FRETURN:
36 return float.class.getName();
37 case Constants.DRETURN:
38 return double.class.getName();
39 case Constants.ARETURN:
40 return Object.class.getName();
41 case Constants.RETURN:
42 return void.class.getName();
43 default:
44 return null;
45 }
46 }
47
48 public TypedInstruction setType(String type) {
49 type = mapType(type, _mappings, true);
50 if (type == null)
51 return (TypedInstruction) setOpcode(Constants.NOP);
52
53 switch (type.charAt(0)) {
54 case 'i':
55 return (TypedInstruction) setOpcode(Constants.IRETURN);
56 case 'l':
57 return (TypedInstruction) setOpcode(Constants.LRETURN);
58 case 'f':
59 return (TypedInstruction) setOpcode(Constants.FRETURN);
60 case 'd':
61 return (TypedInstruction) setOpcode(Constants.DRETURN);
62 case 'v':
63 return (TypedInstruction) setOpcode(Constants.RETURN);
64 default:
65 return (TypedInstruction) setOpcode(Constants.ARETURN);
66 }
67 }
68
69 public int getLogicalStackChange() {
70 switch (getOpcode()) {
71 case Constants.NOP:
72 return 0;
73 default:
74 return -1;
75 }
76 }
77
78 public int getStackChange() {
79 switch (getOpcode()) {
80 case Constants.RETURN:
81 case Constants.NOP:
82 return 0;
83 case Constants.LRETURN:
84 case Constants.DRETURN:
85 return -2;
86 default:
87 return -1;
88 }
89 }
90
91 public void acceptVisit(BCVisitor visit) {
92 visit.enterReturnInstruction(this);
93 visit.exitReturnInstruction(this);
94 }
95 }