1 /*
2 * Copyright (c) 2003, 2025, 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_STACKMAPFRAME_HPP
26 #define SHARE_CLASSFILE_STACKMAPFRAME_HPP
27
28 #include "classfile/verificationType.hpp"
29 #include "classfile/verifier.hpp"
30 #include "oops/method.hpp"
31 #include "runtime/handles.hpp"
32 #include "runtime/signature.hpp"
33 #include "utilities/exceptions.hpp"
34
35 // A StackMapFrame represents one frame in the stack map attribute.
36
37 class TypeContext;
38
39 enum {
40 FLAG_THIS_UNINIT = 0x01
41 };
42
43 class StackMapFrame : public ResourceObj {
44 public:
45 static unsigned int nameandsig_hash(NameAndSig const& field) {
46 Symbol* name = field._name;
47 return (unsigned int) name->identity_hash();
48 }
49
50 static inline bool nameandsig_equals(NameAndSig const& f1, NameAndSig const& f2) {
51 return f1._name == f2._name &&
52 f1._signature == f2._signature;
53 }
54
55 // Maps a strict field's name and signature to whether or not it was initialized
56 typedef ResourceHashtable<NameAndSig, bool, 17,
57 AnyObj::RESOURCE_AREA, mtInternal,
58 nameandsig_hash, nameandsig_equals> AssertUnsetFieldTable;
59 private:
60 int32_t _offset;
61
62 // See comment in StackMapTable about _frame_count about why these
63 // fields are int32_t instead of u2.
64 int32_t _locals_size; // number of valid type elements in _locals
65 int32_t _stack_size; // number of valid type elements in _stack
66
67 int32_t _stack_mark; // Records the size of the stack prior to an
68 // instruction modification, to allow rewinding
69 // when/if an error occurs.
70
71 u2 _max_locals;
72 u2 _max_stack;
73
74 u1 _flags;
75 VerificationType* _locals; // local variable type array
76 VerificationType* _stack; // operand stack type array
77
78 AssertUnsetFieldTable* _assert_unset_fields; // List of unsatisfied strict fields in the basic block
79
80 ClassVerifier* _verifier; // the verifier verifying this method
81
82 StackMapFrame(const StackMapFrame& cp) :
83 ResourceObj(cp),
84 _offset(cp._offset), _locals_size(cp._locals_size),
85 _stack_size(cp._stack_size), _stack_mark(cp._stack_mark),
86 _max_locals(cp._max_locals), _max_stack(cp._max_stack),
87 _flags(cp._flags) {
88 _locals = NEW_RESOURCE_ARRAY(VerificationType, _max_locals);
89 for (int i = 0; i < _max_locals; ++i) {
90 if (i < _locals_size) {
91 _locals[i] = cp._locals[i];
92 } else {
93 _locals[i] = VerificationType::bogus_type();
94 }
95 }
96 int ss = MAX2(_stack_size, _stack_mark);
97 _stack = NEW_RESOURCE_ARRAY(VerificationType, _max_stack);
98 for (int i = 0; i < _max_stack; ++i) {
99 if (i < ss) {
100 _stack[i] = cp._stack[i];
101 } else {
102 _stack[i] = VerificationType::bogus_type();
103 }
104 }
105 _assert_unset_fields = cp._assert_unset_fields;
106 _verifier = nullptr;
107 }
108
109 public:
110 // constructors
111
112 // This constructor is used by the type checker to allocate frames
113 // in type state, which have _max_locals and _max_stack array elements
114 // in _locals and _stack.
115 StackMapFrame(u2 max_locals, u2 max_stack, AssertUnsetFieldTable* initial_strict_fields, ClassVerifier* verifier);
116
117 // This constructor is used to initialize stackmap frames in stackmap table,
118 // which have _locals_size and _stack_size array elements in _locals and _stack.
119 StackMapFrame(int32_t offset,
120 u1 flags,
121 int32_t locals_size,
122 int32_t stack_size,
123 u2 max_locals,
124 u2 max_stack,
125 VerificationType* locals,
126 VerificationType* stack,
127 AssertUnsetFieldTable* assert_unset_fields,
128 ClassVerifier* v) : _offset(offset),
129 _locals_size(locals_size),
130 _stack_size(stack_size),
131 _stack_mark(-1),
132 _max_locals(max_locals),
133 _max_stack(max_stack), _flags(flags),
134 _locals(locals), _stack(stack),
135 _assert_unset_fields(assert_unset_fields),
136 _verifier(v) { }
137
138 static StackMapFrame* copy(StackMapFrame* smf) {
139 return new StackMapFrame(*smf);
140 }
141
142 inline void set_offset(int32_t offset) { _offset = offset; }
143 inline void set_verifier(ClassVerifier* v) { _verifier = v; }
144 inline void set_flags(u1 flags) { _flags = flags; }
145 inline void set_locals_size(int32_t locals_size) { _locals_size = locals_size; }
146 inline void set_stack_size(int32_t stack_size) { _stack_size = _stack_mark = stack_size; }
147 inline void clear_stack() { _stack_size = 0; }
148 inline int32_t offset() const { return _offset; }
149 inline ClassVerifier* verifier() const { return _verifier; }
150 inline u1 flags() const { return _flags; }
151 inline int32_t locals_size() const { return _locals_size; }
152 inline VerificationType* locals() const { return _locals; }
153 inline int32_t stack_size() const { return _stack_size; }
154 inline VerificationType* stack() const { return _stack; }
155 inline u2 max_locals() const { return _max_locals; }
156 inline u2 max_stack() const { return _max_stack; }
157 inline bool flag_this_uninit() const { return _flags & FLAG_THIS_UNINIT; }
158
159 AssertUnsetFieldTable* assert_unset_fields() const {
160 return _assert_unset_fields;
161 }
162
163 void set_assert_unset_fields(AssertUnsetFieldTable* table) {
164 _assert_unset_fields = table;
165 }
166
167 // Called when verifying putfields to mark strict instance fields as satisfied
168 bool satisfy_unset_field(Symbol* name, Symbol* signature) {
169 NameAndSig dummy_field(name, signature);
170
171 if (_assert_unset_fields->contains(dummy_field)) {
172 _assert_unset_fields->put(dummy_field, true);
173 return true;
174 }
175 return false;
176 }
177
178 // Verify that all strict fields have been initialized
179 // Strict fields must be initialized before the super constructor is called
180 bool verify_unset_fields_satisfied() {
181 bool all_satisfied = true;
182 auto check_satisfied = [&] (const NameAndSig& key, const bool& value) {
183 all_satisfied &= value;
184 };
185 _assert_unset_fields->iterate_all(check_satisfied);
186 return all_satisfied;
187 }
188
189 // Merge incoming unset strict fields from StackMapTable with
190 // initial strict instance fields
191 AssertUnsetFieldTable* merge_unset_fields(AssertUnsetFieldTable* new_fields) {
192 auto merge_satisfied = [&] (const NameAndSig& key, const bool& value) {
193 if (!new_fields->contains(key)) {
194 new_fields->put(key, true);
195 }
196 };
197 _assert_unset_fields->iterate_all(merge_satisfied);
198 return new_fields;
199 }
200
201 // Verify that strict fields are compatible between the current frame and the successor
202 // Called during merging of frames
203 bool verify_unset_fields_compatibility(AssertUnsetFieldTable* target_table) const {
204 bool compatible = true;
205 auto is_unset = [&] (const NameAndSig& key, const bool& value) {
206 // Successor must have same debts as current frame
207 if (!value) {
208 if (*target_table->get(key) == true) {
209 compatible = false;
210 }
211 }
212 };
213 _assert_unset_fields->iterate_all(is_unset);
214 return compatible;
215 }
216
217 void unsatisfied_strict_fields_error(InstanceKlass* ik, int bci);
218 static void print_strict_fields(AssertUnsetFieldTable* table);
219
220 // Set locals and stack types to bogus
221 inline void reset() {
222 int32_t i;
223 for (i = 0; i < _max_locals; i++) {
224 _locals[i] = VerificationType::bogus_type();
225 }
226 for (i = 0; i < _max_stack; i++) {
227 _stack[i] = VerificationType::bogus_type();
228 }
229 }
230
231 // Return a StackMapFrame with the same local variable array and empty stack.
232 // Stack array is allocate with unused one element.
233 StackMapFrame* frame_in_exception_handler(u1 flags);
234
235 // Set local variable type array based on m's signature.
236 VerificationType set_locals_from_arg(
237 const methodHandle& m, VerificationType thisKlass);
238
239 // Search local variable type array and stack type array.
240 // Set every element with type of old_object to new_object.
241 void initialize_object(
242 VerificationType old_object, VerificationType new_object);
243
244 // Copy local variable type array in src into this local variable type array.
245 void copy_locals(const StackMapFrame* src);
246
247 // Copy stack type array in src into this stack type array.
248 void copy_stack(const StackMapFrame* src);
249
250 // Return true if this stack map frame is assignable to target.
251 bool is_assignable_to(
252 const StackMapFrame* target, ErrorContext* ctx, TRAPS) const;
253
254 inline void set_mark() {
255 #ifdef ASSERT
256 // Put bogus type to indicate it's no longer valid.
257 if (_stack_mark != -1) {
258 for (int i = _stack_mark - 1; i >= _stack_size; --i) {
259 _stack[i] = VerificationType::bogus_type();
260 }
261 }
262 #endif // def ASSERT
263 _stack_mark = _stack_size;
264 }
265
266 // Used when an error occurs and we want to reset the stack to the state
267 // it was before operands were popped off.
268 void restore() {
269 if (_stack_mark != -1) {
270 _stack_size = _stack_mark;
271 }
272 }
273
274 // Push type into stack type array.
275 inline void push_stack(VerificationType type, TRAPS) {
276 assert(!type.is_check(), "Must be a real type");
277 if (_stack_size >= _max_stack) {
278 verifier()->verify_error(
279 ErrorContext::stack_overflow(_offset, this),
280 "Operand stack overflow");
281 return;
282 }
283 _stack[_stack_size++] = type;
284 }
285
286 inline void push_stack_2(
287 VerificationType type1, VerificationType type2, TRAPS) {
288 assert(type1.is_long() || type1.is_double(), "must be long/double");
289 assert(type2.is_long2() || type2.is_double2(), "must be long/double_2");
290 if (_stack_size >= _max_stack - 1) {
291 verifier()->verify_error(
292 ErrorContext::stack_overflow(_offset, this),
293 "Operand stack overflow");
294 return;
295 }
296 _stack[_stack_size++] = type1;
297 _stack[_stack_size++] = type2;
298 }
299
300 // Pop and return the top type on stack without verifying.
301 inline VerificationType pop_stack(TRAPS) {
302 if (_stack_size <= 0) {
303 verifier()->verify_error(
304 ErrorContext::stack_underflow(_offset, this),
305 "Operand stack underflow");
306 return VerificationType::bogus_type();
307 }
308 VerificationType top = _stack[--_stack_size];
309 return top;
310 }
311
312 // Pop and return the top type on stack type array after verifying it
313 // is assignable to type.
314 inline VerificationType pop_stack(VerificationType type, TRAPS) {
315 if (_stack_size != 0) {
316 VerificationType top = _stack[_stack_size - 1];
317 bool subtype = type.is_assignable_from(
318 top, verifier(), false, CHECK_(VerificationType::bogus_type()));
319 if (subtype) {
320 --_stack_size;
321 return top;
322 }
323 }
324 return pop_stack_ex(type, THREAD);
325 }
326
327 inline void pop_stack_2(
328 VerificationType type1, VerificationType type2, TRAPS) {
329 assert(type1.is_long2() || type1.is_double2(), "must be long/double");
330 assert(type2.is_long() || type2.is_double(), "must be long/double_2");
331 if (_stack_size >= 2) {
332 VerificationType top1 = _stack[_stack_size - 1];
333 bool subtype1 = type1.is_assignable_from(top1, verifier(), false, CHECK);
334 VerificationType top2 = _stack[_stack_size - 2];
335 bool subtype2 = type2.is_assignable_from(top2, verifier(), false, CHECK);
336 if (subtype1 && subtype2) {
337 _stack_size -= 2;
338 return;
339 }
340 }
341 pop_stack_ex(type1, THREAD);
342 pop_stack_ex(type2, THREAD);
343 }
344
345 VerificationType local_at(int index) {
346 return _locals[index];
347 }
348
349 VerificationType stack_at(int index) {
350 return _stack[index];
351 }
352
353 // Uncommon case that throws exceptions.
354 VerificationType pop_stack_ex(VerificationType type, TRAPS);
355
356 // Return the type at index in local variable array after verifying
357 // it is assignable to type.
358 VerificationType get_local(int32_t index, VerificationType type, TRAPS);
359 // For long/double.
360 void get_local_2(
361 int32_t index, VerificationType type1, VerificationType type2, TRAPS);
362
363 // Set element at index in local variable array to type.
364 void set_local(int32_t index, VerificationType type, TRAPS);
365 // For long/double.
366 void set_local_2(
367 int32_t index, VerificationType type1, VerificationType type2, TRAPS);
368
369 // Private auxiliary method used only in is_assignable_to(StackMapFrame).
370 // Returns true if src is assignable to target.
371 int is_assignable_to(
372 VerificationType* src, VerificationType* target, int32_t len, TRAPS) const;
373
374 TypeOrigin stack_top_ctx();
375
376 void print_on(outputStream* str) const;
377 };
378
379 #endif // SHARE_CLASSFILE_STACKMAPFRAME_HPP