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1
4 package gnu.bytecode;
5 import java.io.*;
6
7
10
11 public class LocalVarsAttr extends Attribute
12 {
13 private Method method;
14
15
16 Variable[] used;
17 public Scope current_scope;
18 Scope parameter_scope;
19
20
21 public LocalVarsAttr(CodeAttr code)
22 {
23 super("LocalVariableTable");
24 addToFrontOf(code);
25 method = (Method) code.getContainer();
26 code.locals = this;
27 }
28
29
30 public LocalVarsAttr(Method method)
31 {
32 super("LocalVariableTable");
33 CodeAttr code = method.code;
34 this.method = method;
35 code.locals = this;
36 }
37
38 public final Method getMethod() { return method; }
39
40 public VarEnumerator allVars ()
41 {
42 return new VarEnumerator (parameter_scope);
43 }
44
45 public void enterScope (Scope scope) {
46 scope.linkChild (current_scope);
47 current_scope = scope;
48 CodeAttr code = method.getCode();
49 for (Variable var = scope.firstVar (); var != null; var = var.nextVar ())
50 {
51 if (var.isSimple ())
52 {
53 if (! var.isAssigned ())
54 var.allocateLocal(code);
55 else if (used[var.offset] == null)
56 used[var.offset] = var;
57 else if (used[var.offset] != var)
58 throw new Error  ("inconsistent local variable assignments for "
59 +var+" != "+used[var.offset]);
60 }
61 }
62 }
63
64
68 public void preserveVariablesUpto(Scope scope)
69 {
70 for (Scope cur = current_scope; cur != scope; cur = cur.parent)
71 cur.preserved = true;
72 }
73
74 public final boolean isEmpty ()
75 {
76 VarEnumerator vars = allVars();
77 Variable var;
78 while ((var = vars.nextVar ()) != null)
79 {
80 if (var.isSimple () && var.name != null)
81 return false;
82 }
83 return true;
84 }
85
86 public final int getCount ()
87 {
88 int local_variable_count = 0;
89 VarEnumerator vars = allVars();
90 Variable var;
91 while ((var = vars.nextVar ()) != null)
92 {
93 if (var.shouldEmit())
94 local_variable_count++;
95 }
96 return local_variable_count;
97 }
98
99 public final int getLength()
100 {
101 return 2 + 10 * getCount();
102 }
103
104 public void assignConstants (ClassType cl)
105 {
106 super.assignConstants(cl);
107
108 VarEnumerator vars = allVars ();
109 Variable var;
110 while ((var = vars.nextVar ()) != null)
111 {
112 if (var.isSimple () && var.name != null)
113 {
114 if (var.name_index == 0)
115 var.name_index = cl.getConstants().addUtf8(var.getName()).index;
116 if (var.signature_index == 0)
117 var.signature_index
118 = cl.getConstants().addUtf8(var.getType().signature).index;
119 }
120 }
121 }
122
123 public void write (DataOutputStream dstr) throws java.io.IOException
124 {
125 VarEnumerator vars = allVars ();
126 Variable var;
127 dstr.writeShort (getCount());
128
129 for (vars.reset (); (var = vars.nextVar ()) != null; )
130 {
131 if (var.shouldEmit())
132 {
133 Scope scope = var.scope;
134 int start_pc = scope.start.position;
135 int end_pc = scope.end.position;
136 dstr.writeShort(start_pc);
137 dstr.writeShort(end_pc - start_pc);
138 dstr.writeShort(var.name_index);
139 dstr.writeShort(var.signature_index);
140 dstr.writeShort(var.offset);
141 }
142 }
143 }
144
145 public void print (ClassTypeWriter dst)
146 {
147 VarEnumerator vars = allVars ();
148 dst.print("Attribute \"");
149 dst.print(getName());
150 dst.print("\", length:");
151 dst.print(getLength());
152 dst.print(", count: ");
153 dst.println(getCount());
154
155 Variable var;
156 for (vars.reset (); (var = vars.nextVar ()) != null; )
157 {
158 if (var.isSimple () && var.name != null)
159 {
160 dst.print(" slot#");
161 dst.print(var.offset);
162 dst.print(": name: ");
163 dst.printOptionalIndex(var.name_index);
164 dst.print(var.getName());
165 dst.print(", type: ");
166 dst.printOptionalIndex(var.signature_index);
167 dst.printSignature(var.getType());
168 dst.print(" (pc: ");
169 Scope scope = var.scope;
170 int start_pc, end_pc;
171 if (scope == null || scope.start == null || scope.end == null
172 || (start_pc = scope.start.position) < 0
173 || (end_pc = scope.end.position) < 0)
174 dst.print("unknown");
175 else
176 {
177 dst.print(start_pc);
178 dst.print(" length: ");
179 dst.print(end_pc - start_pc);
180 }
181 dst.println(')');
182 }
183 }
184 }
185 }
186 |
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