1 /*
2 * Copyright (c) 2003, 2019, 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.
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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_CLASSFILE_VERIFICATIONTYPE_HPP
26 #define SHARE_CLASSFILE_VERIFICATIONTYPE_HPP
27
28 #include "classfile/systemDictionary.hpp"
29 #include "oops/instanceKlass.hpp"
30 #include "oops/oop.hpp"
31 #include "oops/symbol.hpp"
32 #include "runtime/handles.hpp"
33 #include "runtime/signature.hpp"
34
35 enum {
36 // As specifed in the JVM spec
37 ITEM_Top = 0,
38 ITEM_Integer = 1,
39 ITEM_Float = 2,
40 ITEM_Double = 3,
41 ITEM_Long = 4,
42 ITEM_Null = 5,
43 ITEM_UninitializedThis = 6,
44 ITEM_Object = 7,
45 ITEM_Uninitialized = 8,
46 ITEM_Bogus = (uint)-1
47 };
48
49 class ClassVerifier;
50
51 class VerificationType {
52 private:
53 // Least significant bits of _handle are always 0, so we use these as
54 // the indicator that the _handle is valid. Otherwise, the _data field
55 // contains encoded data (as specified below). Should the VM change
56 // and the lower bits on oops aren't 0, the assert in the constructor
57 // will catch this and we'll have to add a descriminator tag to this
58 // structure.
59 union {
60 Symbol* _sym;
61 uintptr_t _data;
62 } _u;
63
64 enum {
65 // These rest are not found in classfiles, but used by the verifier
66 ITEM_Boolean = 9, ITEM_Byte, ITEM_Short, ITEM_Char,
67 ITEM_Long_2nd, ITEM_Double_2nd
68 };
69
70 // Enum for the _data field
71 enum {
72 // Bottom three bits determine if the type is a reference, value type,
73 // primitive, uninitialized or a query-type.
74 TypeMask = 0x00000007,
75
76 // Topmost types encoding
77 Reference = 0x0, // _sym contains the name of an object
78 Primitive = 0x1, // see below for primitive list
79 Uninitialized = 0x2, // 0x00ffff00 contains bci
80 TypeQuery = 0x3, // Meta-types used for category testing
81 ValueType = 0x4, // _sym contains the name of a value type
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 ValueTypeFlag = 0x08, // For value type query types
89 NonScalarFlag = 0x10, // For either value type or reference queries
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 NonScalarQuery = (NonScalarFlag << 1 * BitsPerByte) | TypeQuery
124 };
125
126 VerificationType(uintptr_t raw_data) {
127 _u._data = raw_data;
128 }
129
130 public:
131
132 VerificationType() { *this = bogus_type(); }
133
134 // Create verification types
135 static VerificationType bogus_type() { return VerificationType(Bogus); }
136 static VerificationType top_type() { return bogus_type(); } // alias
137 static VerificationType null_type() { return VerificationType(Null); }
138 static VerificationType integer_type() { return VerificationType(Integer); }
139 static VerificationType float_type() { return VerificationType(Float); }
140 static VerificationType long_type() { return VerificationType(Long); }
141 static VerificationType long2_type() { return VerificationType(Long_2nd); }
142 static VerificationType double_type() { return VerificationType(Double); }
143 static VerificationType boolean_type() { return VerificationType(Boolean); }
144 static VerificationType byte_type() { return VerificationType(Byte); }
145 static VerificationType char_type() { return VerificationType(Char); }
146 static VerificationType short_type() { return VerificationType(Short); }
147 static VerificationType double2_type()
148 { return VerificationType(Double_2nd); }
149
150 // "check" types are used for queries. A "check" type is not assignable
151 // to anything, but the specified types are assignable to a "check". For
152 // example, any category1 primitive is assignable to category1_check and
153 // any reference is assignable to reference_check.
154 static VerificationType reference_check()
155 { return VerificationType(ReferenceQuery); }
156 static VerificationType valuetype_check()
157 { return VerificationType(ValueTypeQuery); }
158 static VerificationType category1_check()
159 { return VerificationType(Category1Query); }
160 static VerificationType category2_check()
161 { return VerificationType(Category2Query); }
162 static VerificationType category2_2nd_check()
163 { return VerificationType(Category2_2ndQuery); }
164 static VerificationType nonscalar_check()
165 { return VerificationType(NonScalarQuery); }
166
167 // For reference types, store the actual Symbol
168 static VerificationType reference_type(Symbol* sh) {
169 assert(((uintptr_t)sh & TypeMask) == 0, "Symbols must be aligned");
170 // If the above assert fails in the future because oop* isn't aligned,
171 // then this type encoding system will have to change to have a tag value
172 // to descriminate between oops and primitives.
173 return VerificationType((uintptr_t)sh);
174 }
175 static VerificationType uninitialized_type(u2 bci)
176 { return VerificationType(bci << 1 * BitsPerByte | Uninitialized); }
177 static VerificationType uninitialized_this_type()
178 { return uninitialized_type(BciForThis); }
179
180 // For value types, store the actual Symbol* and set the 3rd bit.
181 // Provides a way for a value type to be distinguished from a reference type.
182 static VerificationType valuetype_type(Symbol* sh) {
183 assert(((uintptr_t)sh & TypeMask) == 0, "Symbols must be aligned");
184 assert((uintptr_t)sh != 0, "Null is not a valid value type");
185 // If the above assert fails in the future because oop* isn't aligned,
186 // then this type encoding system will have to change to have a tag value
187 // to descriminate between oops and primitives.
188 return VerificationType((uintptr_t)sh | ValueType);
189 }
190
191 // Create based on u1 read from classfile
192 static VerificationType from_tag(u1 tag);
193
194 bool is_bogus() const { return (_u._data == Bogus); }
195 bool is_null() const { return (_u._data == Null); }
196 bool is_boolean() const { return (_u._data == Boolean); }
197 bool is_byte() const { return (_u._data == Byte); }
198 bool is_char() const { return (_u._data == Char); }
199 bool is_short() const { return (_u._data == Short); }
200 bool is_integer() const { return (_u._data == Integer); }
201 bool is_long() const { return (_u._data == Long); }
202 bool is_float() const { return (_u._data == Float); }
203 bool is_double() const { return (_u._data == Double); }
204 bool is_long2() const { return (_u._data == Long_2nd); }
205 bool is_double2() const { return (_u._data == Double_2nd); }
206 bool is_reference() const { return (((_u._data & TypeMask) == Reference) && !is_valuetype_check()); }
207 bool is_valuetype() const { return ((_u._data & TypeMask) == ValueType); }
208 bool is_category1() const {
209 // This should return true for all one-word types, which are category1
210 // primitives, references (including uninitialized refs) and value types.
211 // Though the 'query' types should technically return 'false' here, if we
212 // allow this to return true, we can perform the test using only
213 // 2 operations rather than 8 (3 masks, 3 compares and 2 logical 'ands').
214 // Since noone should call this on a query type anyway, this is ok.
215 assert(!is_check(), "Must not be a check type (wrong value returned)");
216 return ((_u._data & Category1) != Primitive);
217 // should only return false if it's a primitive, and the category1 flag
218 // is not set.
219 }
220 bool is_category2() const { return ((_u._data & Category2) == Category2); }
221 bool is_category2_2nd() const {
222 return ((_u._data & Category2_2nd) == Category2_2nd);
223 }
224 bool is_reference_check() const { return _u._data == ReferenceQuery; }
225 bool is_valuetype_check() const { return _u._data == ValueTypeQuery; }
226 bool is_nonscalar_check() const { return _u._data == NonScalarQuery; }
227 bool is_category1_check() const { return _u._data == Category1Query; }
228 bool is_category2_check() const { return _u._data == Category2Query; }
229 bool is_category2_2nd_check() const { return _u._data == Category2_2ndQuery; }
230 bool is_check() const { return (_u._data & TypeQuery) == TypeQuery; }
231
232 bool is_x_array(char sig) const {
233 return is_null() || (is_array() && (name()->char_at(1) == sig));
234 }
235 bool is_int_array() const { return is_x_array('I'); }
236 bool is_byte_array() const { return is_x_array('B'); }
237 bool is_bool_array() const { return is_x_array('Z'); }
238 bool is_char_array() const { return is_x_array('C'); }
239 bool is_short_array() const { return is_x_array('S'); }
240 bool is_long_array() const { return is_x_array('J'); }
241 bool is_float_array() const { return is_x_array('F'); }
242 bool is_double_array() const { return is_x_array('D'); }
243 bool is_object_array() const { return is_x_array('L'); }
244 bool is_value_array() const { return is_x_array('Q'); }
245 bool is_array_array() const { return is_x_array('['); }
246 bool is_reference_array() const
247 { return is_object_array() || is_array_array(); }
248 bool is_nonscalar_array() const
249 { return is_object_array() || is_array_array() || is_value_array(); }
250 bool is_object() const
251 { return (is_reference() && !is_null() && name()->utf8_length() >= 1 &&
252 name()->char_at(0) != '['); }
253 bool is_array() const
254 { return (is_reference() && !is_null() && name()->utf8_length() >= 2 &&
255 name()->char_at(0) == '['); }
256 bool is_uninitialized() const
257 { return ((_u._data & Uninitialized) == Uninitialized); }
258 bool is_uninitialized_this() const
259 { return is_uninitialized() && bci() == BciForThis; }
260
261 VerificationType to_category2_2nd() const {
262 assert(is_category2(), "Must be a double word");
263 return VerificationType(is_long() ? Long_2nd : Double_2nd);
264 }
265
266 static VerificationType change_ref_to_valuetype(VerificationType ref) {
267 assert(ref.is_reference(), "Bad arg");
268 assert(!ref.is_null(), "Unexpected NULL");
269 return valuetype_type(ref.name());
270 }
271
272 u2 bci() const {
273 assert(is_uninitialized(), "Must be uninitialized type");
274 return ((_u._data & BciMask) >> 1 * BitsPerByte);
275 }
276
277 Symbol* name() const {
278 assert(!is_null() && (is_reference() || is_valuetype()), "Must be a non-null reference or a value type");
279 return (is_reference() ? _u._sym : ((Symbol*)(_u._data & ~(uintptr_t)ValueType)));
280 }
281
282 bool equals(const VerificationType& t) const {
283 return (_u._data == t._u._data ||
284 (((is_reference() && t.is_reference()) ||
285 (is_valuetype() && t.is_valuetype())) &&
286 !is_null() && !t.is_null() && name() == t.name()));
287
288 }
289
290 bool operator ==(const VerificationType& t) const {
291 return equals(t);
292 }
293
294 bool operator !=(const VerificationType& t) const {
295 return !equals(t);
296 }
297
298 // The whole point of this type system - check to see if one type
299 // is assignable to another. Returns true if one can assign 'from' to
300 // this.
301 bool is_assignable_from(
302 const VerificationType& from, ClassVerifier* context,
303 bool from_field_is_protected, TRAPS) const {
304 if (equals(from) || is_bogus()) {
305 return true;
306 } else {
307 switch(_u._data) {
308 case Category1Query:
309 return from.is_category1();
310 case Category2Query:
311 return from.is_category2();
312 case Category2_2ndQuery:
313 return from.is_category2_2nd();
314 case ReferenceQuery:
315 return from.is_reference() || from.is_uninitialized();
316 case NonScalarQuery:
317 return from.is_reference() || from.is_uninitialized() ||
318 from.is_valuetype();
319 case ValueTypeQuery:
320 return from.is_valuetype();
321 case Boolean:
322 case Byte:
323 case Char:
324 case Short:
325 // An int can be assigned to boolean, byte, char or short values.
326 return from.is_integer();
327 default:
328 if (is_valuetype()) {
329 return is_valuetype_assignable_from(from);
330 } else if (is_reference() && from.is_valuetype()) {
331 return is_ref_assignable_from_value_type(from, context, THREAD);
332 } else if (is_reference() && from.is_reference()) {
333 return is_reference_assignable_from(from, context,
334 from_field_is_protected,
335 THREAD);
336 } else {
337 return false;
338 }
339 }
340 }
341 }
342
343 // Check to see if one array component type is assignable to another.
344 // Same as is_assignable_from() except int primitives must be identical.
345 bool is_component_assignable_from(
346 const VerificationType& from, ClassVerifier* context,
347 bool from_field_is_protected, TRAPS) const {
348 if (equals(from) || is_bogus()) {
349 return true;
350 } else {
351 switch(_u._data) {
352 case Boolean:
353 case Byte:
354 case Char:
355 case Short:
356 return false;
357 default:
358 return is_assignable_from(from, context, from_field_is_protected, THREAD);
359 }
360 }
361 }
362
363 VerificationType get_component(ClassVerifier* context, TRAPS) const;
364
365 int dimensions() const {
366 assert(is_array(), "Must be an array");
367 int index = 0;
368 while (name()->char_at(index) == '[') index++;
369 return index;
370 }
371
372 void print_on(outputStream* st) const;
373
374 private:
375
376 bool is_reference_assignable_from(
377 const VerificationType&, ClassVerifier*, bool from_field_is_protected,
378 TRAPS) const;
379
380 bool is_valuetype_assignable_from(const VerificationType& from) const;
381
382 bool is_ref_assignable_from_value_type(const VerificationType& from, ClassVerifier* context, TRAPS) const;
383
384
385 public:
386 static bool resolve_and_check_assignability(InstanceKlass* klass, Symbol* name,
387 Symbol* from_name, bool from_field_is_protected,
388 bool from_is_array, bool from_is_object,
389 TRAPS);
390 };
391
392 #endif // SHARE_CLASSFILE_VERIFICATIONTYPE_HPP