1 /*
2 * Copyright (c) 2003, 2023, 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_CLASSFILE_VERIFICATIONTYPE_HPP
26 #define SHARE_CLASSFILE_VERIFICATIONTYPE_HPP
27
28 #include "oops/instanceKlass.hpp"
29 #include "oops/oop.hpp"
30 #include "oops/symbol.hpp"
31 #include "runtime/handles.hpp"
32 #include "runtime/signature.hpp"
33
34 enum : uint {
35 // As specified in the JVM spec
36 ITEM_Top = 0,
37 ITEM_Integer = 1,
38 ITEM_Float = 2,
39 ITEM_Double = 3,
40 ITEM_Long = 4,
41 ITEM_Null = 5,
42 ITEM_UninitializedThis = 6,
43 ITEM_Object = 7,
44 ITEM_Uninitialized = 8,
45 ITEM_Bogus = (uint)-1
46 };
47
48 class ClassVerifier;
49
50 class VerificationType {
51 private:
52 // Least significant bits of _handle are always 0, so we use these as
53 // the indicator that the _handle is valid. Otherwise, the _data field
54 // contains encoded data (as specified below). Should the VM change
55 // and the lower bits on oops aren't 0, the assert in the constructor
56 // will catch this and we'll have to add a descriminator tag to this
57 // structure.
58 union {
59 Symbol* _sym;
60 uintptr_t _data;
61 } _u;
62
63 enum {
64 // These rest are not found in classfiles, but used by the verifier
65 ITEM_Boolean = 9, ITEM_Byte, ITEM_Short, ITEM_Char,
66 ITEM_Long_2nd, ITEM_Double_2nd
67 };
68
69 // Enum for the _data field
70 enum : uint {
71 // Bottom three bits determine if the type is a reference, inline type,
72 // primitive, uninitialized or a query-type.
73 TypeMask = 0x00000007,
74
75 // Topmost types encoding
76 Reference = 0x0, // _sym contains the name of an object
77 Primitive = 0x1, // see below for primitive list
78 Uninitialized = 0x2, // 0x00ffff00 contains bci
79 TypeQuery = 0x3, // Meta-types used for category testing
80 InlineType = 0x4, // _sym contains the name of an inline type
81
82 // Utility flags
83 ReferenceFlag = 0x00, // For reference query types
84 Category1Flag = 0x01, // One-word values
85 Category2Flag = 0x02, // First word of a two-word value
86 Category2_2ndFlag = 0x04, // Second word of a two-word value
87 InlineTypeFlag = 0x08, // For inline type query types
88 NonScalarFlag = 0x10, // For either inline type or reference queries
89
90 // special reference values
91 Null = 0x00000000, // A reference with a 0 sym is null
92
93 // Primitives categories (the second byte determines the category)
94 Category1 = (Category1Flag << 1 * BitsPerByte) | Primitive,
95 Category2 = (Category2Flag << 1 * BitsPerByte) | Primitive,
96 Category2_2nd = (Category2_2ndFlag << 1 * BitsPerByte) | Primitive,
97
98 // Primitive values (type descriminator stored in most-signifcant bytes)
99 // Bogus needs the " | Primitive". Else, is_reference(Bogus) returns TRUE.
100 Bogus = (ITEM_Bogus << 2 * BitsPerByte) | Primitive,
101 Boolean = (ITEM_Boolean << 2 * BitsPerByte) | Category1,
102 Byte = (ITEM_Byte << 2 * BitsPerByte) | Category1,
103 Short = (ITEM_Short << 2 * BitsPerByte) | Category1,
104 Char = (ITEM_Char << 2 * BitsPerByte) | Category1,
105 Integer = (ITEM_Integer << 2 * BitsPerByte) | Category1,
106 Float = (ITEM_Float << 2 * BitsPerByte) | Category1,
107 Long = (ITEM_Long << 2 * BitsPerByte) | Category2,
108 Double = (ITEM_Double << 2 * BitsPerByte) | Category2,
109 Long_2nd = (ITEM_Long_2nd << 2 * BitsPerByte) | Category2_2nd,
110 Double_2nd = (ITEM_Double_2nd << 2 * BitsPerByte) | Category2_2nd,
111
112 // Used by Uninitialized (second and third bytes hold the bci)
113 BciMask = 0xffff << 1 * BitsPerByte,
114 BciForThis = ((u2)-1), // A bci of -1 is an Unintialized-This
115
116 // Query values
117 ReferenceQuery = (ReferenceFlag << 1 * BitsPerByte) | TypeQuery,
118 Category1Query = (Category1Flag << 1 * BitsPerByte) | TypeQuery,
119 Category2Query = (Category2Flag << 1 * BitsPerByte) | TypeQuery,
120 Category2_2ndQuery = (Category2_2ndFlag << 1 * BitsPerByte) | TypeQuery,
121 InlineTypeQuery = (InlineTypeFlag << 1 * BitsPerByte) | TypeQuery,
122 NonScalarQuery = (NonScalarFlag << 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 inline_type_check()
156 { return VerificationType(InlineTypeQuery); }
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 static VerificationType nonscalar_check()
164 { return VerificationType(NonScalarQuery); }
165
166 // For reference types, store the actual Symbol
167 static VerificationType reference_type(Symbol* sh) {
168 assert(((uintptr_t)sh & TypeMask) == 0, "Symbols must be aligned");
169 // If the above assert fails in the future because oop* isn't aligned,
170 // then this type encoding system will have to change to have a tag value
171 // to discriminate between oops and primitives.
172 return VerificationType((uintptr_t)sh);
173 }
174 static VerificationType uninitialized_type(u2 bci)
175 { return VerificationType(bci << 1 * BitsPerByte | Uninitialized); }
176 static VerificationType uninitialized_this_type()
177 { return uninitialized_type(BciForThis); }
178
179 // For inline types, store the actual Symbol* and set the 3rd bit.
180 // Provides a way for an inline type to be distinguished from a reference type.
181 static VerificationType inline_type(Symbol* sh) {
182 assert(((uintptr_t)sh & TypeMask) == 0, "Symbols must be aligned");
183 assert((uintptr_t)sh != 0, "Null is not a valid inline type");
184 // If the above assert fails in the future because oop* isn't aligned,
185 // then this type encoding system will have to change to have a tag value
186 // to discriminate between oops and primitives.
187 return VerificationType((uintptr_t)sh | InlineType);
188 }
189
190 // Create based on u1 read from classfile
191 static VerificationType from_tag(u1 tag);
192
193 bool is_bogus() const { return (_u._data == Bogus); }
194 bool is_null() const { return (_u._data == Null); }
195 bool is_boolean() const { return (_u._data == Boolean); }
196 bool is_byte() const { return (_u._data == Byte); }
197 bool is_char() const { return (_u._data == Char); }
198 bool is_short() const { return (_u._data == Short); }
199 bool is_integer() const { return (_u._data == Integer); }
200 bool is_long() const { return (_u._data == Long); }
201 bool is_float() const { return (_u._data == Float); }
202 bool is_double() const { return (_u._data == Double); }
203 bool is_long2() const { return (_u._data == Long_2nd); }
204 bool is_double2() const { return (_u._data == Double_2nd); }
205 bool is_reference() const { return (((_u._data & TypeMask) == Reference) && !is_inline_type_check()); }
206 bool is_inline_type() const { return ((_u._data & TypeMask) == InlineType); }
207 bool is_category1() const {
208 // This should return true for all one-word types, which are category1
209 // primitives, references (including uninitialized refs) and inline types.
210 // Though the 'query' types should technically return 'false' here, if we
211 // allow this to return true, we can perform the test using only
212 // 2 operations rather than 8 (3 masks, 3 compares and 2 logical 'ands').
213 // Since no one should call this on a query type anyway, this is ok.
214 assert(!is_check(), "Must not be a check type (wrong value returned)");
215 return ((_u._data & Category1) != Primitive);
216 // should only return false if it's a primitive, and the category1 flag
217 // is not set.
218 }
219 bool is_category2() const { return ((_u._data & Category2) == Category2); }
220 bool is_category2_2nd() const {
221 return ((_u._data & Category2_2nd) == Category2_2nd);
222 }
223 bool is_reference_check() const { return _u._data == ReferenceQuery; }
224 bool is_inline_type_check() const { return _u._data == InlineTypeQuery; }
225 bool is_nonscalar_check() const { return _u._data == NonScalarQuery; }
226 bool is_category1_check() const { return _u._data == Category1Query; }
227 bool is_category2_check() const { return _u._data == Category2Query; }
228 bool is_category2_2nd_check() const { return _u._data == Category2_2ndQuery; }
229 bool is_check() const { return (_u._data & TypeQuery) == TypeQuery; }
230
231 bool is_x_array(char sig) const {
232 return is_null() || (is_array() && (name()->char_at(1) == sig));
233 }
234 bool is_int_array() const { return is_x_array(JVM_SIGNATURE_INT); }
235 bool is_byte_array() const { return is_x_array(JVM_SIGNATURE_BYTE); }
236 bool is_bool_array() const { return is_x_array(JVM_SIGNATURE_BOOLEAN); }
237 bool is_char_array() const { return is_x_array(JVM_SIGNATURE_CHAR); }
238 bool is_short_array() const { return is_x_array(JVM_SIGNATURE_SHORT); }
239 bool is_long_array() const { return is_x_array(JVM_SIGNATURE_LONG); }
240 bool is_float_array() const { return is_x_array(JVM_SIGNATURE_FLOAT); }
241 bool is_double_array() const { return is_x_array(JVM_SIGNATURE_DOUBLE); }
242 bool is_object_array() const { return is_x_array(JVM_SIGNATURE_CLASS); }
243 bool is_array_array() const { return is_x_array(JVM_SIGNATURE_ARRAY); }
244 bool is_inline_type_array() const { return is_x_array(JVM_SIGNATURE_PRIMITIVE_OBJECT); }
245 bool is_reference_array() const
246 { return is_object_array() || is_array_array(); }
247 bool is_nonscalar_array() const
248 { return is_object_array() || is_array_array() || is_inline_type_array(); }
249 bool is_object() const
250 { return (is_reference() && !is_null() && name()->utf8_length() >= 1 &&
251 name()->char_at(0) != JVM_SIGNATURE_ARRAY); }
252 bool is_array() const
253 { return (is_reference() && !is_null() && name()->utf8_length() >= 2 &&
254 name()->char_at(0) == JVM_SIGNATURE_ARRAY); }
255 bool is_uninitialized() const
256 { return ((_u._data & Uninitialized) == Uninitialized); }
257 bool is_uninitialized_this() const
258 { return is_uninitialized() && bci() == BciForThis; }
259
260 VerificationType to_category2_2nd() const {
261 assert(is_category2(), "Must be a double word");
262 return VerificationType(is_long() ? Long_2nd : Double_2nd);
263 }
264
265 static VerificationType change_ref_to_inline_type(VerificationType ref) {
266 assert(ref.is_reference(), "Bad arg");
267 assert(!ref.is_null(), "Unexpected nullptr");
268 return inline_type(ref.name());
269 }
270
271 u2 bci() const {
272 assert(is_uninitialized(), "Must be uninitialized type");
273 return ((_u._data & BciMask) >> 1 * BitsPerByte);
274 }
275
276 Symbol* name() const {
277 assert(!is_null() && (is_reference() || is_inline_type()), "Must be a non-null reference or an inline type");
278 return (is_reference() ? _u._sym : ((Symbol*)(_u._data & ~(uintptr_t)InlineType)));
279 }
280
281 bool equals(const VerificationType& t) const {
282 return (_u._data == t._u._data ||
283 (((is_reference() && t.is_reference()) ||
284 (is_inline_type() && t.is_inline_type())) &&
285 !is_null() && !t.is_null() && name() == t.name()));
286
287 }
288
289 bool operator ==(const VerificationType& t) const {
290 return equals(t);
291 }
292
293 bool operator !=(const VerificationType& t) const {
294 return !equals(t);
295 }
296
297 // The whole point of this type system - check to see if one type
298 // is assignable to another. Returns true if one can assign 'from' to
299 // this.
300 bool is_assignable_from(
301 const VerificationType& from, ClassVerifier* context,
302 bool from_field_is_protected, TRAPS) const {
303 if (equals(from) || is_bogus()) {
304 return true;
305 } else {
306 switch(_u._data) {
307 case Category1Query:
308 return from.is_category1();
309 case Category2Query:
310 return from.is_category2();
311 case Category2_2ndQuery:
312 return from.is_category2_2nd();
313 case ReferenceQuery:
314 return from.is_reference() || from.is_uninitialized();
315 case NonScalarQuery:
316 return from.is_reference() || from.is_uninitialized() ||
317 from.is_inline_type();
318 case InlineTypeQuery:
319 return from.is_inline_type();
320 case Boolean:
321 case Byte:
322 case Char:
323 case Short:
324 // An int can be assigned to boolean, byte, char or short values.
325 return from.is_integer();
326 default:
327 if (is_inline_type()) {
328 return is_inline_type_assignable_from(from);
329 } else if (is_reference() && from.is_inline_type()) {
330 return is_ref_assignable_from_inline_type(from, context, THREAD);
331 } else if (is_reference() && from.is_reference()) {
332 return is_reference_assignable_from(from, context,
333 from_field_is_protected,
334 THREAD);
335 } else {
336 return false;
337 }
338 }
339 }
340 }
341
342 // Check to see if one array component type is assignable to another.
343 // Same as is_assignable_from() except int primitives must be identical.
344 bool is_component_assignable_from(
345 const VerificationType& from, ClassVerifier* context,
346 bool from_field_is_protected, TRAPS) const {
347 if (equals(from) || is_bogus()) {
348 return true;
349 } else {
350 switch(_u._data) {
351 case Boolean:
352 case Byte:
353 case Char:
354 case Short:
355 return false;
356 default:
357 return is_assignable_from(from, context, from_field_is_protected, THREAD);
358 }
359 }
360 }
361
362 VerificationType get_component(ClassVerifier* context) const;
363
364 int dimensions() const {
365 assert(is_array(), "Must be an array");
366 int index = 0;
367 while (name()->char_at(index) == JVM_SIGNATURE_ARRAY) index++;
368 return index;
369 }
370
371 void print_on(outputStream* st) const;
372
373 private:
374
375 bool is_reference_assignable_from(
376 const VerificationType&, ClassVerifier*, bool from_field_is_protected,
377 TRAPS) const;
378
379 bool is_inline_type_assignable_from(const VerificationType& from) const;
380
381 bool is_ref_assignable_from_inline_type(const VerificationType& from, ClassVerifier* context, TRAPS) const;
382
383
384 public:
385 static bool resolve_and_check_assignability(InstanceKlass* klass, Symbol* name,
386 Symbol* from_name, bool from_field_is_protected,
387 bool from_is_array, bool from_is_object,
388 TRAPS);
389 };
390
391 #endif // SHARE_CLASSFILE_VERIFICATIONTYPE_HPP