1 /*
2 * Copyright (c) 2003, 2017, 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.
22 *
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 three bits determine if the type is a reference, value type,
74 // primitive, uninitialized or a query-type.
75 TypeMask = 0x00000007,
76
77 // Topmost types encoding
78 Reference = 0x0, // _sym contains the name of an object
79 Primitive = 0x1, // see below for primitive list
80 Uninitialized = 0x2, // 0x00ffff00 contains bci
81 TypeQuery = 0x3, // Meta-types used for category testing
82 ValueType = 0x4, // _sym contains the name of a value type
83
84 // Utility flags
85 ReferenceFlag = 0x00, // For reference query types
86 Category1Flag = 0x01, // One-word values
87 Category2Flag = 0x02, // First word of a two-word value
88 Category2_2ndFlag = 0x04, // Second word of a two-word value
89 ValueTypeFlag = 0x08, // For value type query types
90
91 // special reference values
92 Null = 0x00000000, // A reference with a 0 sym is null
93
94 // Primitives categories (the second byte determines the category)
95 Category1 = (Category1Flag << 1 * BitsPerByte) | Primitive,
96 Category2 = (Category2Flag << 1 * BitsPerByte) | Primitive,
97 Category2_2nd = (Category2_2ndFlag << 1 * BitsPerByte) | Primitive,
98
99 // Primitive values (type descriminator stored in most-signifcant bytes)
100 // Bogus needs the " | Primitive". Else, is_reference(Bogus) returns TRUE.
101 Bogus = (ITEM_Bogus << 2 * BitsPerByte) | Primitive,
102 Boolean = (ITEM_Boolean << 2 * BitsPerByte) | Category1,
103 Byte = (ITEM_Byte << 2 * BitsPerByte) | Category1,
104 Short = (ITEM_Short << 2 * BitsPerByte) | Category1,
105 Char = (ITEM_Char << 2 * BitsPerByte) | Category1,
106 Integer = (ITEM_Integer << 2 * BitsPerByte) | Category1,
107 Float = (ITEM_Float << 2 * BitsPerByte) | Category1,
108 Long = (ITEM_Long << 2 * BitsPerByte) | Category2,
109 Double = (ITEM_Double << 2 * BitsPerByte) | Category2,
110 Long_2nd = (ITEM_Long_2nd << 2 * BitsPerByte) | Category2_2nd,
111 Double_2nd = (ITEM_Double_2nd << 2 * BitsPerByte) | Category2_2nd,
112
113 // Used by Uninitialized (second and third bytes hold the bci)
114 BciMask = 0xffff << 1 * BitsPerByte,
115 BciForThis = ((u2)-1), // A bci of -1 is an Unintialized-This
116
117 // Query values
118 ReferenceQuery = (ReferenceFlag << 1 * BitsPerByte) | TypeQuery,
119 Category1Query = (Category1Flag << 1 * BitsPerByte) | TypeQuery,
120 Category2Query = (Category2Flag << 1 * BitsPerByte) | TypeQuery,
121 Category2_2ndQuery = (Category2_2ndFlag << 1 * BitsPerByte) | TypeQuery,
122 ValueTypeQuery = (ValueTypeFlag << 1 * BitsPerByte) | TypeQuery
123 };
124
125 VerificationType(uintptr_t raw_data) {
126 _u._data = raw_data;
127 }
128
129 public:
130
131 VerificationType() { *this = bogus_type(); }
132
133 // Create verification types
134 static VerificationType bogus_type() { return VerificationType(Bogus); }
135 static VerificationType top_type() { return bogus_type(); } // alias
136 static VerificationType null_type() { return VerificationType(Null); }
137 static VerificationType integer_type() { return VerificationType(Integer); }
138 static VerificationType float_type() { return VerificationType(Float); }
139 static VerificationType long_type() { return VerificationType(Long); }
140 static VerificationType long2_type() { return VerificationType(Long_2nd); }
141 static VerificationType double_type() { return VerificationType(Double); }
142 static VerificationType boolean_type() { return VerificationType(Boolean); }
143 static VerificationType byte_type() { return VerificationType(Byte); }
144 static VerificationType char_type() { return VerificationType(Char); }
145 static VerificationType short_type() { return VerificationType(Short); }
146 static VerificationType double2_type()
147 { return VerificationType(Double_2nd); }
148
149 // "check" types are used for queries. A "check" type is not assignable
150 // to anything, but the specified types are assignable to a "check". For
151 // example, any category1 primitive is assignable to category1_check and
152 // any reference is assignable to reference_check.
153 static VerificationType reference_check()
154 { return VerificationType(ReferenceQuery); }
155 static VerificationType valuetype_check()
156 { return VerificationType(ValueTypeQuery); }
157 static VerificationType category1_check()
158 { return VerificationType(Category1Query); }
159 static VerificationType category2_check()
160 { return VerificationType(Category2Query); }
161 static VerificationType category2_2nd_check()
162 { return VerificationType(Category2_2ndQuery); }
163
164 // For reference types, store the actual Symbol
165 static VerificationType reference_type(Symbol* sh) {
166 assert(((uintptr_t)sh & TypeMask) == 0, "Symbols must be aligned");
167 // If the above assert fails in the future because oop* isn't aligned,
168 // then this type encoding system will have to change to have a tag value
169 // to descriminate between oops and primitives.
170 return VerificationType((uintptr_t)sh);
171 }
172 static VerificationType uninitialized_type(u2 bci)
173 { return VerificationType(bci << 1 * BitsPerByte | Uninitialized); }
174 static VerificationType uninitialized_this_type()
175 { return uninitialized_type(BciForThis); }
176
177 // For value types, store the actual Symbol* and set the 3rd bit.
178 // Provides a way for a value type to be distinguished from a reference type.
179 static VerificationType valuetype_type(Symbol* sh) {
180 assert(((uintptr_t)sh & TypeMask) == 0, "Symbols must be aligned");
181 assert((uintptr_t)sh != 0, "Null is not a valid value type");
182 // If the above assert fails in the future because oop* isn't aligned,
183 // then this type encoding system will have to change to have a tag value
184 // to descriminate between oops and primitives.
185 return VerificationType((uintptr_t)sh | ValueType);
186 }
187
188 // Create based on u1 read from classfile
189 static VerificationType from_tag(u1 tag);
190
191 bool is_bogus() const { return (_u._data == Bogus); }
192 bool is_null() const { return (_u._data == Null); }
193 bool is_boolean() const { return (_u._data == Boolean); }
194 bool is_byte() const { return (_u._data == Byte); }
195 bool is_char() const { return (_u._data == Char); }
196 bool is_short() const { return (_u._data == Short); }
197 bool is_integer() const { return (_u._data == Integer); }
198 bool is_long() const { return (_u._data == Long); }
199 bool is_float() const { return (_u._data == Float); }
200 bool is_double() const { return (_u._data == Double); }
201 bool is_long2() const { return (_u._data == Long_2nd); }
202 bool is_double2() const { return (_u._data == Double_2nd); }
203 bool is_reference() const { return (((_u._data & TypeMask) == Reference) && !is_valuetype_check()); }
204 bool is_valuetype() const { return ((_u._data & TypeMask) == ValueType); }
205 bool is_category1() const {
206 // This should return true for all one-word types, which are category1
207 // primitives, references (including uninitialized refs) and value types.
208 // Though the 'query' types should technically return 'false' here, if we
209 // allow this to return true, we can perform the test using only
210 // 2 operations rather than 8 (3 masks, 3 compares and 2 logical 'ands').
211 // Since noone should call this on a query type anyway, this is ok.
212 assert(!is_check(), "Must not be a check type (wrong value returned)");
213 return ((_u._data & Category1) != Primitive);
214 // should only return false if it's a primitive, and the category1 flag
215 // is not set.
216 }
217 bool is_category2() const { return ((_u._data & Category2) == Category2); }
218 bool is_category2_2nd() const {
219 return ((_u._data & Category2_2nd) == Category2_2nd);
220 }
221 bool is_reference_check() const { return _u._data == ReferenceQuery; }
222 bool is_valuetype_check() const { return _u._data == ValueTypeQuery; }
223 bool is_category1_check() const { return _u._data == Category1Query; }
224 bool is_category2_check() const { return _u._data == Category2Query; }
225 bool is_category2_2nd_check() const { return _u._data == Category2_2ndQuery; }
226 bool is_check() const { return (_u._data & TypeQuery) == TypeQuery; }
227
228 bool is_x_array(char sig) const {
229 return is_null() || (is_array() && (name()->byte_at(1) == sig));
230 }
231 bool is_int_array() const { return is_x_array('I'); }
232 bool is_byte_array() const { return is_x_array('B'); }
233 bool is_bool_array() const { return is_x_array('Z'); }
234 bool is_char_array() const { return is_x_array('C'); }
235 bool is_short_array() const { return is_x_array('S'); }
236 bool is_long_array() const { return is_x_array('J'); }
237 bool is_float_array() const { return is_x_array('F'); }
238 bool is_double_array() const { return is_x_array('D'); }
239 bool is_object_array() const { return is_x_array('L'); }
240 bool is_value_array() const { return is_x_array('Q'); }
241 bool is_array_array() const { return is_x_array('['); }
242 bool is_reference_array() const
243 { return is_object_array() || is_array_array(); }
244 bool is_object() const
245 { return (is_reference() && !is_null() && name()->utf8_length() >= 1 &&
246 name()->byte_at(0) != '['); }
247 bool is_array() const
248 { return (is_reference() && !is_null() && name()->utf8_length() >= 2 &&
249 name()->byte_at(0) == '['); }
250 bool is_uninitialized() const
251 { return ((_u._data & Uninitialized) == Uninitialized); }
252 bool is_uninitialized_this() const
253 { return is_uninitialized() && bci() == BciForThis; }
254
255 VerificationType to_category2_2nd() const {
256 assert(is_category2(), "Must be a double word");
257 return VerificationType(is_long() ? Long_2nd : Double_2nd);
258 }
259
260 u2 bci() const {
261 assert(is_uninitialized(), "Must be uninitialized type");
262 return ((_u._data & BciMask) >> 1 * BitsPerByte);
263 }
264
265 Symbol* name() const {
266 assert(!is_null() && (is_reference() || is_valuetype()), "Must be a non-null reference or a value type");
267 return (is_reference() ? _u._sym : ((Symbol*)(_u._data & ~(uintptr_t)ValueType)));
268 }
269
270 bool equals(const VerificationType& t) const {
271 return (_u._data == t._u._data ||
272 (((is_reference() && t.is_reference()) || (is_valuetype() && t.is_valuetype())) &&
273 !is_null() && !t.is_null() && name() == t.name()));
274 }
275
276 bool operator ==(const VerificationType& t) const {
277 return equals(t);
278 }
279
280 bool operator !=(const VerificationType& t) const {
281 return !equals(t);
282 }
283
284 // The whole point of this type system - check to see if one type
285 // is assignable to another. Returns true if one can assign 'from' to
286 // this.
287 bool is_assignable_from(
288 const VerificationType& from, ClassVerifier* context,
289 bool from_field_is_protected, TRAPS) const {
290 if (equals(from) || is_bogus()) {
291 return true;
292 } else {
293 switch(_u._data) {
294 case Category1Query:
295 return from.is_category1();
296 case Category2Query:
297 return from.is_category2();
298 case Category2_2ndQuery:
299 return from.is_category2_2nd();
300 case ReferenceQuery:
301 return from.is_reference() || from.is_uninitialized();
302 case ValueTypeQuery:
303 return from.is_valuetype();
304 case Boolean:
305 case Byte:
306 case Char:
307 case Short:
308 // An int can be assigned to boolean, byte, char or short values.
309 return from.is_integer();
310 default:
311 if (is_reference() && from.is_reference()) {
312 return is_reference_assignable_from(from, context,
313 from_field_is_protected,
314 THREAD);
315 } else if (is_valuetype() && from.is_valuetype()) {
316 return is_valuetype_assignable_from(from, context, THREAD);
317 } else {
318 return false;
319 }
320 }
321 }
322 }
323
324 // Check to see if one array component type is assignable to another.
325 // Same as is_assignable_from() except int primitives must be identical.
326 bool is_component_assignable_from(
327 const VerificationType& from, ClassVerifier* context,
328 bool from_field_is_protected, TRAPS) const {
329 if (equals(from) || is_bogus()) {
330 return true;
331 } else {
332 switch(_u._data) {
333 case Boolean:
334 case Byte:
335 case Char:
336 case Short:
337 return false;
338 default:
339 return is_assignable_from(from, context, from_field_is_protected, CHECK_false);
340 }
341 }
342 }
343
344 VerificationType get_component(ClassVerifier* context, TRAPS) const;
345
346 int dimensions() const {
347 assert(is_array(), "Must be an array");
348 int index = 0;
349 while (name()->byte_at(index) == '[') index++;
350 return index;
351 }
352
353 void print_on(outputStream* st) const;
354
355 private:
356
357 bool is_reference_assignable_from(
358 const VerificationType&, ClassVerifier*, bool from_field_is_protected,
359 TRAPS) const;
360
361 bool is_valuetype_assignable_from(const VerificationType& from, ClassVerifier* context, TRAPS) const {
362 // 1. Check names - two value types are assignable if they have the same name
363 // 2. Check java/lang/__Value - from may be trying to be assigned to a __Value parameter
364 assert(is_valuetype() && from.is_valuetype(), "Is value type assignable called with a non-value type");
365 return (name() == from.name() ||
366 name() == vmSymbols::java_lang____Value());
367 }
368
369 public:
370 static bool resolve_and_check_assignability(InstanceKlass* klass, Symbol* name,
371 Symbol* from_name, bool from_field_is_protected,
372 bool from_is_array, bool from_is_object,
373 TRAPS);
374 };
375
376 #endif // SHARE_VM_CLASSFILE_VERIFICATIONTYPE_HPP