1 /*
2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
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23 */
24
25 #ifndef SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP
26 #define SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP
27
28 #include "classfile/systemDictionary.hpp"
29 #include "memory/allocation.hpp"
30 #include "oops/instanceKlass.hpp"
31 #include "oops/oop.hpp"
32 #include "oops/symbol.hpp"
33 #include "runtime/handles.hpp"
34 #include "runtime/signature.hpp"
35
36 enum {
37 // As specifed in the JVM spec
38 ITEM_Top = 0,
39 ITEM_Integer = 1,
40 ITEM_Float = 2,
41 ITEM_Double = 3,
42 ITEM_Long = 4,
43 ITEM_Null = 5,
44 ITEM_UninitializedThis = 6,
45 ITEM_Object = 7,
46 ITEM_Uninitialized = 8,
47 ITEM_Bogus = (uint)-1
48 };
49
50 class ClassVerifier;
51
52 class VerificationType VALUE_OBJ_CLASS_SPEC {
53 private:
54 // Least significant bits of _handle are always 0, so we use these as
55 // the indicator that the _handle is valid. Otherwise, the _data field
56 // contains encoded data (as specified below). Should the VM change
57 // and the lower bits on oops aren't 0, the assert in the constructor
58 // will catch this and we'll have to add a descriminator tag to this
59 // structure.
60 union {
61 Symbol* _sym;
62 uintptr_t _data;
63 } _u;
64
65 enum {
66 // These rest are not found in classfiles, but used by the verifier
67 ITEM_Boolean = 9, ITEM_Byte, ITEM_Short, ITEM_Char,
68 ITEM_Long_2nd, ITEM_Double_2nd
69 };
70
71 // Enum for the _data field
72 enum {
73 // Bottom two bits determine if the type is a reference, primitive,
74 // uninitialized or a query-type.
75 TypeMask = 0x00000003,
76
77 // Topmost types encoding
78 Reference = 0x0, // _sym contains the name
79 Primitive = 0x1, // see below for primitive list
80 Uninitialized = 0x2, // 0x00ffff00 contains bci
81 TypeQuery = 0x3, // Meta-types used for category testing
82
83 // Utility flags
84 ReferenceFlag = 0x00, // For reference query types
85 Category1Flag = 0x01, // One-word values
86 Category2Flag = 0x02, // First word of a two-word value
87 Category2_2ndFlag = 0x04, // Second word of a two-word value
88
89 // special reference values
90 Null = 0x00000000, // A reference with a 0 sym is null
91
92 // Primitives categories (the second byte determines the category)
93 Category1 = (Category1Flag << 1 * BitsPerByte) | Primitive,
94 Category2 = (Category2Flag << 1 * BitsPerByte) | Primitive,
95 Category2_2nd = (Category2_2ndFlag << 1 * BitsPerByte) | Primitive,
96
97 // Primitive values (type descriminator stored in most-signifcant bytes)
98 // Bogus needs the " | Primitive". Else, is_reference(Bogus) returns TRUE.
99 Bogus = (ITEM_Bogus << 2 * BitsPerByte) | Primitive,
100 Boolean = (ITEM_Boolean << 2 * BitsPerByte) | Category1,
101 Byte = (ITEM_Byte << 2 * BitsPerByte) | Category1,
102 Short = (ITEM_Short << 2 * BitsPerByte) | Category1,
103 Char = (ITEM_Char << 2 * BitsPerByte) | Category1,
104 Integer = (ITEM_Integer << 2 * BitsPerByte) | Category1,
105 Float = (ITEM_Float << 2 * BitsPerByte) | Category1,
106 Long = (ITEM_Long << 2 * BitsPerByte) | Category2,
107 Double = (ITEM_Double << 2 * BitsPerByte) | Category2,
108 Long_2nd = (ITEM_Long_2nd << 2 * BitsPerByte) | Category2_2nd,
109 Double_2nd = (ITEM_Double_2nd << 2 * BitsPerByte) | Category2_2nd,
110
111 // Used by Uninitialized (second and third bytes hold the bci)
112 BciMask = 0xffff << 1 * BitsPerByte,
113 BciForThis = ((u2)-1), // A bci of -1 is an Unintialized-This
114
115 // Query values
116 ReferenceQuery = (ReferenceFlag << 1 * BitsPerByte) | TypeQuery,
117 Category1Query = (Category1Flag << 1 * BitsPerByte) | TypeQuery,
118 Category2Query = (Category2Flag << 1 * BitsPerByte) | TypeQuery,
119 Category2_2ndQuery = (Category2_2ndFlag << 1 * BitsPerByte) | TypeQuery
120 };
121
122 VerificationType(uintptr_t raw_data) {
123 _u._data = raw_data;
124 }
125
126 public:
127
128 VerificationType() { *this = bogus_type(); }
129
130 // Create verification types
131 static VerificationType bogus_type() { return VerificationType(Bogus); }
132 static VerificationType top_type() { return bogus_type(); } // alias
133 static VerificationType null_type() { return VerificationType(Null); }
134 static VerificationType integer_type() { return VerificationType(Integer); }
135 static VerificationType float_type() { return VerificationType(Float); }
136 static VerificationType long_type() { return VerificationType(Long); }
137 static VerificationType long2_type() { return VerificationType(Long_2nd); }
138 static VerificationType double_type() { return VerificationType(Double); }
139 static VerificationType boolean_type() { return VerificationType(Boolean); }
140 static VerificationType byte_type() { return VerificationType(Byte); }
141 static VerificationType char_type() { return VerificationType(Char); }
142 static VerificationType short_type() { return VerificationType(Short); }
143 static VerificationType double2_type()
144 { return VerificationType(Double_2nd); }
145
146 // "check" types are used for queries. A "check" type is not assignable
147 // to anything, but the specified types are assignable to a "check". For
148 // example, any category1 primitive is assignable to category1_check and
149 // any reference is assignable to reference_check.
150 static VerificationType reference_check()
151 { return VerificationType(ReferenceQuery); }
152 static VerificationType category1_check()
153 { return VerificationType(Category1Query); }
154 static VerificationType category2_check()
155 { return VerificationType(Category2Query); }
156 static VerificationType category2_2nd_check()
157 { return VerificationType(Category2_2ndQuery); }
158
159 // For reference types, store the actual Symbol
160 static VerificationType reference_type(Symbol* sh) {
161 assert(((uintptr_t)sh & 0x3) == 0, "Symbols must be aligned");
162 // If the above assert fails in the future because oop* isn't aligned,
163 // then this type encoding system will have to change to have a tag value
164 // to descriminate between oops and primitives.
165 return VerificationType((uintptr_t)sh);
166 }
167 static VerificationType uninitialized_type(u2 bci)
168 { return VerificationType(bci << 1 * BitsPerByte | Uninitialized); }
169 static VerificationType uninitialized_this_type()
170 { return uninitialized_type(BciForThis); }
171
172 // Create based on u1 read from classfile
173 static VerificationType from_tag(u1 tag);
174
175 bool is_bogus() const { return (_u._data == Bogus); }
176 bool is_null() const { return (_u._data == Null); }
177 bool is_boolean() const { return (_u._data == Boolean); }
178 bool is_byte() const { return (_u._data == Byte); }
179 bool is_char() const { return (_u._data == Char); }
180 bool is_short() const { return (_u._data == Short); }
181 bool is_integer() const { return (_u._data == Integer); }
182 bool is_long() const { return (_u._data == Long); }
183 bool is_float() const { return (_u._data == Float); }
184 bool is_double() const { return (_u._data == Double); }
185 bool is_long2() const { return (_u._data == Long_2nd); }
186 bool is_double2() const { return (_u._data == Double_2nd); }
187 bool is_reference() const { return ((_u._data & TypeMask) == Reference); }
188 bool is_category1() const {
189 // This should return true for all one-word types, which are category1
190 // primitives, and references (including uninitialized refs). Though
191 // the 'query' types should technically return 'false' here, if we
192 // allow this to return true, we can perform the test using only
193 // 2 operations rather than 8 (3 masks, 3 compares and 2 logical 'ands').
194 // Since noone should call this on a query type anyway, this is ok.
195 assert(!is_check(), "Must not be a check type (wrong value returned)");
196 return ((_u._data & Category1) != Primitive);
197 // should only return false if it's a primitive, and the category1 flag
198 // is not set.
199 }
200 bool is_category2() const { return ((_u._data & Category2) == Category2); }
201 bool is_category2_2nd() const {
202 return ((_u._data & Category2_2nd) == Category2_2nd);
203 }
204 bool is_reference_check() const { return _u._data == ReferenceQuery; }
205 bool is_category1_check() const { return _u._data == Category1Query; }
206 bool is_category2_check() const { return _u._data == Category2Query; }
207 bool is_category2_2nd_check() const { return _u._data == Category2_2ndQuery; }
208 bool is_check() const { return (_u._data & TypeQuery) == TypeQuery; }
209
210 bool is_x_array(char sig) const {
211 return is_null() || (is_array() && (name()->byte_at(1) == sig));
212 }
213 bool is_int_array() const { return is_x_array('I'); }
214 bool is_byte_array() const { return is_x_array('B'); }
215 bool is_bool_array() const { return is_x_array('Z'); }
216 bool is_char_array() const { return is_x_array('C'); }
217 bool is_short_array() const { return is_x_array('S'); }
218 bool is_long_array() const { return is_x_array('J'); }
219 bool is_float_array() const { return is_x_array('F'); }
220 bool is_double_array() const { return is_x_array('D'); }
221 bool is_object_array() const { return is_x_array('L'); }
222 bool is_array_array() const { return is_x_array('['); }
223 bool is_reference_array() const
224 { return is_object_array() || is_array_array(); }
225 bool is_object() const
226 { return (is_reference() && !is_null() && name()->utf8_length() >= 1 &&
227 name()->byte_at(0) != '['); }
228 bool is_array() const
229 { return (is_reference() && !is_null() && name()->utf8_length() >= 2 &&
230 name()->byte_at(0) == '['); }
231 bool is_uninitialized() const
232 { return ((_u._data & Uninitialized) == Uninitialized); }
233 bool is_uninitialized_this() const
234 { return is_uninitialized() && bci() == BciForThis; }
235
236 VerificationType to_category2_2nd() const {
237 assert(is_category2(), "Must be a double word");
238 return VerificationType(is_long() ? Long_2nd : Double_2nd);
239 }
240
241 u2 bci() const {
242 assert(is_uninitialized(), "Must be uninitialized type");
243 return ((_u._data & BciMask) >> 1 * BitsPerByte);
244 }
245
246 Symbol* name() const {
247 assert(is_reference() && !is_null(), "Must be a non-null reference");
248 return _u._sym;
249 }
250
251 bool equals(const VerificationType& t) const {
252 return (_u._data == t._u._data ||
253 (is_reference() && t.is_reference() && !is_null() && !t.is_null() &&
254 name() == t.name()));
255 }
256
257 bool operator ==(const VerificationType& t) const {
258 return equals(t);
259 }
260
261 bool operator !=(const VerificationType& t) const {
262 return !equals(t);
263 }
264
265 // The whole point of this type system - check to see if one type
266 // is assignable to another. Returns true if one can assign 'from' to
267 // this.
268 bool is_assignable_from(
269 const VerificationType& from, ClassVerifier* context,
270 bool from_field_is_protected, TRAPS) const {
271 if (equals(from) || is_bogus()) {
272 return true;
273 } else {
274 switch(_u._data) {
275 case Category1Query:
276 return from.is_category1();
277 case Category2Query:
278 return from.is_category2();
279 case Category2_2ndQuery:
280 return from.is_category2_2nd();
281 case ReferenceQuery:
282 return from.is_reference() || from.is_uninitialized();
283 case Boolean:
284 case Byte:
285 case Char:
286 case Short:
287 // An int can be assigned to boolean, byte, char or short values.
288 return from.is_integer();
289 default:
290 if (is_reference() && from.is_reference()) {
291 return is_reference_assignable_from(from, context,
292 from_field_is_protected,
293 THREAD);
294 } else {
295 return false;
296 }
297 }
298 }
299 }
300
301 // Check to see if one array component type is assignable to another.
302 // Same as is_assignable_from() except int primitives must be identical.
303 bool is_component_assignable_from(
304 const VerificationType& from, ClassVerifier* context,
305 bool from_field_is_protected, TRAPS) const {
306 if (equals(from) || is_bogus()) {
307 return true;
308 } else {
309 switch(_u._data) {
310 case Boolean:
311 case Byte:
312 case Char:
313 case Short:
314 return false;
315 default:
316 return is_assignable_from(from, context, from_field_is_protected, CHECK_false);
317 }
318 }
319 }
320
321 VerificationType get_component(ClassVerifier* context, TRAPS) const;
322
323 int dimensions() const {
324 assert(is_array(), "Must be an array");
325 int index = 0;
326 while (name()->byte_at(index) == '[') index++;
327 return index;
328 }
329
330 void print_on(outputStream* st) const;
331
332 private:
333
334 bool is_reference_assignable_from(
335 const VerificationType&, ClassVerifier*, bool from_field_is_protected,
336 TRAPS) const;
337
338 public:
339 static bool resolve_and_check_assignability(instanceKlassHandle klass, Symbol* name,
340 Symbol* from_name, bool from_field_is_protected,
341 bool from_is_array, bool from_is_object,
342 TRAPS);
343 };
344
345 #endif // SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP
--- EOF ---