1 /*
2 * Copyright (c) 2003, 2014, 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 #include "precompiled.hpp"
26 #include "classfile/stackMapTable.hpp"
27 #include "classfile/verifier.hpp"
28 #include "memory/resourceArea.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "runtime/fieldType.hpp"
31 #include "runtime/handles.inline.hpp"
32
33 StackMapTable::StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
34 u2 max_locals, u2 max_stack,
35 char* code_data, int code_len, TRAPS) {
36 _code_length = code_len;
37 _frame_count = reader->get_frame_count();
38 if (_frame_count > 0) {
39 _frame_array = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD,
40 StackMapFrame*, _frame_count);
41 StackMapFrame* pre_frame = init_frame;
42 for (int32_t i = 0; i < _frame_count; i++) {
43 StackMapFrame* frame = reader->next(
44 pre_frame, i == 0, max_locals, max_stack,
45 CHECK_VERIFY(pre_frame->verifier()));
46 _frame_array[i] = frame;
47 int offset = frame->offset();
48 if (offset >= code_len || code_data[offset] == 0) {
49 frame->verifier()->verify_error(
50 ErrorContext::bad_stackmap(i, frame),
51 "StackMapTable error: bad offset");
52 return;
53 }
54 pre_frame = frame;
55 }
56 }
57 reader->check_end(CHECK);
58 }
59
60 // This method is only called by method in StackMapTable.
61 int StackMapTable::get_index_from_offset(int32_t offset) const {
62 int i = 0;
63 for (; i < _frame_count; i++) {
64 if (_frame_array[i]->offset() == offset) {
65 return i;
66 }
67 }
68 return i; // frame with offset doesn't exist in the array
69 }
70
71 bool StackMapTable::match_stackmap(
72 StackMapFrame* frame, int32_t target,
73 bool match, bool update, ErrorContext* ctx, TRAPS) const {
74 int index = get_index_from_offset(target);
75 return match_stackmap(frame, target, index, match, update, ctx, THREAD);
76 }
77
78 // Match and/or update current_frame to the frame in stackmap table with
79 // specified offset and frame index. Return true if the two frames match.
80 //
81 // The values of match and update are: _match__update_
82 //
83 // checking a branch target/exception handler: true false
84 // linear bytecode verification following an
85 // unconditional branch: false true
86 // linear bytecode verification not following an
87 // unconditional branch: true true
88 bool StackMapTable::match_stackmap(
89 StackMapFrame* frame, int32_t target, int32_t frame_index,
90 bool match, bool update, ErrorContext* ctx, TRAPS) const {
91 if (frame_index < 0 || frame_index >= _frame_count) {
92 *ctx = ErrorContext::missing_stackmap(frame->offset());
93 frame->verifier()->verify_error(
94 *ctx, "Expecting a stackmap frame at branch target %d", target);
95 return false;
96 }
97
98 StackMapFrame *stackmap_frame = _frame_array[frame_index];
99 bool result = true;
100 if (match) {
101 // when checking handler target, match == true && update == false
102 bool is_exception_handler = !update;
103 // Has direct control flow from last instruction, need to match the two
104 // frames.
105 result = frame->is_assignable_to(stackmap_frame, is_exception_handler,
106 ctx, CHECK_VERIFY_(frame->verifier(), result));
107 }
108 if (update) {
109 // Use the frame in stackmap table as current frame
110 int lsize = stackmap_frame->locals_size();
111 int ssize = stackmap_frame->stack_size();
112 if (frame->locals_size() > lsize || frame->stack_size() > ssize) {
113 // Make sure unused type array items are all _bogus_type.
114 frame->reset();
115 }
116 frame->set_locals_size(lsize);
117 frame->copy_locals(stackmap_frame);
118 frame->set_stack_size(ssize);
119 frame->copy_stack(stackmap_frame);
120 frame->set_flags(stackmap_frame->flags());
121 }
122 return result;
123 }
124
125 void StackMapTable::check_jump_target(
126 StackMapFrame* frame, int32_t target, TRAPS) const {
127 ErrorContext ctx;
128 bool match = match_stackmap(
129 frame, target, true, false, &ctx, CHECK_VERIFY(frame->verifier()));
130 if (!match || (target < 0 || target >= _code_length)) {
131 frame->verifier()->verify_error(ctx,
132 "Inconsistent stackmap frames at branch target %d", target);
133 return;
134 }
135 // check if uninitialized objects exist on backward branches
136 check_new_object(frame, target, CHECK_VERIFY(frame->verifier()));
137 frame->verifier()->update_furthest_jump(target);
138 }
139
140 void StackMapTable::check_new_object(
141 const StackMapFrame* frame, int32_t target, TRAPS) const {
142 if (frame->offset() > target && frame->has_new_object()) {
143 frame->verifier()->verify_error(
144 ErrorContext::bad_code(frame->offset()),
145 "Uninitialized object exists on backward branch %d", target);
146 return;
147 }
148 }
149
150 void StackMapTable::print_on(outputStream* str) const {
151 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
152 str->indent().print_cr("table = { ");
153 {
154 streamIndentor si(str);
155 for (int32_t i = 0; i < _frame_count; ++i) {
156 _frame_array[i]->print_on(str);
157 }
158 }
159 str->print_cr(" }");
160 }
161
162 int32_t StackMapReader::chop(
163 VerificationType* locals, int32_t length, int32_t chops) {
164 if (locals == NULL) return -1;
165 int32_t pos = length - 1;
166 for (int32_t i=0; i<chops; i++) {
167 if (locals[pos].is_category2_2nd()) {
168 pos -= 2;
169 } else {
170 pos --;
171 }
172 if (pos<0 && i<(chops-1)) return -1;
173 }
174 return pos+1;
175 }
176
177 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
178 u1 tag = _stream->get_u1(THREAD);
179 if (tag < (u1)ITEM_UninitializedThis) {
180 return VerificationType::from_tag(tag);
181 }
182 if (tag == ITEM_Object) {
183 u2 class_index = _stream->get_u2(THREAD);
184 int nconstants = _cp->length();
185 if ((class_index <= 0 || class_index >= nconstants) ||
186 (!_cp->tag_at(class_index).is_klass() &&
187 !_cp->tag_at(class_index).is_unresolved_klass())) {
188 _stream->stackmap_format_error("bad class index", THREAD);
189 return VerificationType::bogus_type();
190 }
191 return VerificationType::reference_type(_cp->klass_name_at(class_index));
192 }
193 if (tag == ITEM_UninitializedThis) {
194 if (flags != NULL) {
195 *flags |= FLAG_THIS_UNINIT;
196 }
197 return VerificationType::uninitialized_this_type();
198 }
199 if (tag == ITEM_Uninitialized) {
200 u2 offset = _stream->get_u2(THREAD);
201 if (offset >= _code_length ||
202 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
203 ResourceMark rm(THREAD);
204 _verifier->class_format_error(
205 "StackMapTable format error: bad offset for Uninitialized");
206 return VerificationType::bogus_type();
207 }
208 return VerificationType::uninitialized_type(offset);
209 }
210 _stream->stackmap_format_error("bad verification type", THREAD);
211 return VerificationType::bogus_type();
212 }
213
214 StackMapFrame* StackMapReader::next(
215 StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
216 StackMapFrame* frame;
217 int offset;
218 VerificationType* locals = NULL;
219 u1 frame_type = _stream->get_u1(THREAD);
220 if (frame_type < 64) {
221 // same_frame
222 if (first) {
223 offset = frame_type;
224 // Can't share the locals array since that is updated by the verifier.
225 if (pre_frame->locals_size() > 0) {
226 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
227 THREAD, VerificationType, pre_frame->locals_size());
228 }
229 } else {
230 offset = pre_frame->offset() + frame_type + 1;
231 locals = pre_frame->locals();
232 }
233 frame = new StackMapFrame(
234 offset, pre_frame->flags(), pre_frame->locals_size(), 0,
235 max_locals, max_stack, locals, NULL, _verifier);
236 if (first && locals != NULL) {
237 frame->copy_locals(pre_frame);
238 }
239 return frame;
240 }
241 if (frame_type < 128) {
242 // same_locals_1_stack_item_frame
243 if (first) {
244 offset = frame_type - 64;
245 // Can't share the locals array since that is updated by the verifier.
246 if (pre_frame->locals_size() > 0) {
247 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
248 THREAD, VerificationType, pre_frame->locals_size());
249 }
250 } else {
251 offset = pre_frame->offset() + frame_type - 63;
252 locals = pre_frame->locals();
253 }
254 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
255 THREAD, VerificationType, 2);
256 u2 stack_size = 1;
257 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
258 if (stack[0].is_category2()) {
259 stack[1] = stack[0].to_category2_2nd();
260 stack_size = 2;
261 }
262 check_verification_type_array_size(
263 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
264 frame = new StackMapFrame(
265 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
266 max_locals, max_stack, locals, stack, _verifier);
267 if (first && locals != NULL) {
268 frame->copy_locals(pre_frame);
269 }
270 return frame;
271 }
272
273 u2 offset_delta = _stream->get_u2(THREAD);
274
275 if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
276 // reserved frame types
277 _stream->stackmap_format_error(
278 "reserved frame type", CHECK_VERIFY_(_verifier, NULL));
279 }
280
281 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
282 // same_locals_1_stack_item_frame_extended
283 if (first) {
284 offset = offset_delta;
285 // Can't share the locals array since that is updated by the verifier.
286 if (pre_frame->locals_size() > 0) {
287 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
288 THREAD, VerificationType, pre_frame->locals_size());
289 }
290 } else {
291 offset = pre_frame->offset() + offset_delta + 1;
292 locals = pre_frame->locals();
293 }
294 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
295 THREAD, VerificationType, 2);
296 u2 stack_size = 1;
297 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
298 if (stack[0].is_category2()) {
299 stack[1] = stack[0].to_category2_2nd();
300 stack_size = 2;
301 }
302 check_verification_type_array_size(
303 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
304 frame = new StackMapFrame(
305 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
306 max_locals, max_stack, locals, stack, _verifier);
307 if (first && locals != NULL) {
308 frame->copy_locals(pre_frame);
309 }
310 return frame;
311 }
312
313 if (frame_type <= SAME_EXTENDED) {
314 // chop_frame or same_frame_extended
315 locals = pre_frame->locals();
316 int length = pre_frame->locals_size();
317 int chops = SAME_EXTENDED - frame_type;
318 int new_length = length;
319 u1 flags = pre_frame->flags();
320 if (chops != 0) {
321 new_length = chop(locals, length, chops);
322 check_verification_type_array_size(
323 new_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
324 // Recompute flags since uninitializedThis could have been chopped.
325 flags = 0;
326 for (int i=0; i<new_length; i++) {
327 if (locals[i].is_uninitialized_this()) {
328 flags |= FLAG_THIS_UNINIT;
329 break;
330 }
331 }
332 }
333 if (first) {
334 offset = offset_delta;
335 // Can't share the locals array since that is updated by the verifier.
336 if (new_length > 0) {
337 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
338 THREAD, VerificationType, new_length);
339 } else {
340 locals = NULL;
341 }
342 } else {
343 offset = pre_frame->offset() + offset_delta + 1;
344 }
345 frame = new StackMapFrame(
346 offset, flags, new_length, 0, max_locals, max_stack,
347 locals, NULL, _verifier);
348 if (first && locals != NULL) {
349 frame->copy_locals(pre_frame);
350 }
351 return frame;
352 } else if (frame_type < SAME_EXTENDED + 4) {
353 // append_frame
354 int appends = frame_type - SAME_EXTENDED;
355 int real_length = pre_frame->locals_size();
356 int new_length = real_length + appends*2;
357 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
358 VerificationType* pre_locals = pre_frame->locals();
359 int i;
360 for (i=0; i<pre_frame->locals_size(); i++) {
361 locals[i] = pre_locals[i];
362 }
363 u1 flags = pre_frame->flags();
364 for (i=0; i<appends; i++) {
365 locals[real_length] = parse_verification_type(&flags, THREAD);
366 if (locals[real_length].is_category2()) {
367 locals[real_length + 1] = locals[real_length].to_category2_2nd();
368 ++real_length;
369 }
370 ++real_length;
371 }
372 check_verification_type_array_size(
373 real_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
374 if (first) {
375 offset = offset_delta;
376 } else {
377 offset = pre_frame->offset() + offset_delta + 1;
378 }
379 frame = new StackMapFrame(
380 offset, flags, real_length, 0, max_locals,
381 max_stack, locals, NULL, _verifier);
382 return frame;
383 }
384 if (frame_type == FULL) {
385 // full_frame
386 u1 flags = 0;
387 u2 locals_size = _stream->get_u2(THREAD);
388 int real_locals_size = 0;
389 if (locals_size > 0) {
390 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
391 THREAD, VerificationType, locals_size*2);
392 }
393 int i;
394 for (i=0; i<locals_size; i++) {
395 locals[real_locals_size] = parse_verification_type(&flags, THREAD);
396 if (locals[real_locals_size].is_category2()) {
397 locals[real_locals_size + 1] =
398 locals[real_locals_size].to_category2_2nd();
399 ++real_locals_size;
400 }
401 ++real_locals_size;
402 }
403 check_verification_type_array_size(
404 real_locals_size, max_locals, CHECK_VERIFY_(_verifier, NULL));
405 u2 stack_size = _stream->get_u2(THREAD);
406 int real_stack_size = 0;
407 VerificationType* stack = NULL;
408 if (stack_size > 0) {
409 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
410 THREAD, VerificationType, stack_size*2);
411 }
412 for (i=0; i<stack_size; i++) {
413 stack[real_stack_size] = parse_verification_type(NULL, THREAD);
414 if (stack[real_stack_size].is_category2()) {
415 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
416 ++real_stack_size;
417 }
418 ++real_stack_size;
419 }
420 check_verification_type_array_size(
421 real_stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
422 if (first) {
423 offset = offset_delta;
424 } else {
425 offset = pre_frame->offset() + offset_delta + 1;
426 }
427 frame = new StackMapFrame(
428 offset, flags, real_locals_size, real_stack_size,
429 max_locals, max_stack, locals, stack, _verifier);
430 return frame;
431 }
432
433 _stream->stackmap_format_error(
434 "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), NULL));
435 return NULL;
436 }