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, bool handler, ErrorContext* ctx, TRAPS) const {
74 int index = get_index_from_offset(target);
75 return match_stackmap(frame, target, index, match, update, handler, 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 // handler is true if the frame in stackmap_table is for an exception handler.
81 //
82 // The values of match and update are: _match__update__handler
83 //
84 // checking a branch target: true false false
85 // checking an exception handler: true false true
86 // linear bytecode verification following an
87 // unconditional branch: false true false
88 // linear bytecode verification not following an
89 // unconditional branch: true true false
90 bool StackMapTable::match_stackmap(
91 StackMapFrame* frame, int32_t target, int32_t frame_index,
92 bool match, bool update, bool handler, ErrorContext* ctx, TRAPS) const {
93 if (frame_index < 0 || frame_index >= _frame_count) {
94 *ctx = ErrorContext::missing_stackmap(frame->offset());
95 frame->verifier()->verify_error(
96 *ctx, "Expecting a stackmap frame at branch target %d", target);
97 return false;
98 }
99
100 StackMapFrame *stackmap_frame = _frame_array[frame_index];
101 bool result = true;
102 if (match) {
103 // Has direct control flow from last instruction, need to match the two
104 // frames.
105 result = frame->is_assignable_to(stackmap_frame, 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, 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 }
138
139 void StackMapTable::check_new_object(
140 const StackMapFrame* frame, int32_t target, TRAPS) const {
141 int frame_index = get_index_from_offset(target);
142 assert(frame_index >= 0 && frame_index < _frame_count, "bad frame index");
143 if (frame->offset() > target &&
144 frame->has_unique_new_object(_frame_array[frame_index])) {
145 frame->verifier()->verify_error(
146 ErrorContext::bad_code(frame->offset()),
147 "Uninitialized object exists on backward branch %d", target);
148 return;
149 }
150 }
151
152 void StackMapTable::print_on(outputStream* str) const {
153 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
154 str->indent().print_cr("table = { ");
155 {
156 streamIndentor si(str);
157 for (int32_t i = 0; i < _frame_count; ++i) {
158 _frame_array[i]->print_on(str);
159 }
160 }
161 str->print_cr(" }");
162 }
163
164 int32_t StackMapReader::chop(
165 VerificationType* locals, int32_t length, int32_t chops) {
166 if (locals == NULL) return -1;
167 int32_t pos = length - 1;
168 for (int32_t i=0; i<chops; i++) {
169 if (locals[pos].is_category2_2nd()) {
170 pos -= 2;
171 } else {
172 pos --;
173 }
174 if (pos<0 && i<(chops-1)) return -1;
175 }
176 return pos+1;
177 }
178
179 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
180 u1 tag = _stream->get_u1(THREAD);
181 if (tag < (u1)ITEM_UninitializedThis) {
182 return VerificationType::from_tag(tag);
183 }
184 if (tag == ITEM_Object) {
185 u2 class_index = _stream->get_u2(THREAD);
186 int nconstants = _cp->length();
187 if ((class_index <= 0 || class_index >= nconstants) ||
188 (!_cp->tag_at(class_index).is_klass() &&
189 !_cp->tag_at(class_index).is_unresolved_klass())) {
190 _stream->stackmap_format_error("bad class index", THREAD);
191 return VerificationType::bogus_type();
192 }
193 return VerificationType::reference_type(_cp->klass_name_at(class_index));
194 }
195 if (tag == ITEM_UninitializedThis) {
196 if (flags != NULL) {
197 *flags |= FLAG_THIS_UNINIT;
198 }
199 return VerificationType::uninitialized_this_type();
200 }
201 if (tag == ITEM_Uninitialized) {
202 u2 offset = _stream->get_u2(THREAD);
203 if (offset >= _code_length ||
204 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
205 ResourceMark rm(THREAD);
206 _verifier->class_format_error(
207 "StackMapTable format error: bad offset for Uninitialized");
208 return VerificationType::bogus_type();
209 }
210 return VerificationType::uninitialized_type(offset);
211 }
212 _stream->stackmap_format_error("bad verification type", THREAD);
213 return VerificationType::bogus_type();
214 }
215
216 StackMapFrame* StackMapReader::next(
217 StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
218 StackMapFrame* frame;
219 int offset;
220 VerificationType* locals = NULL;
221 u1 frame_type = _stream->get_u1(THREAD);
222 if (frame_type < 64) {
223 // same_frame
224 if (first) {
225 offset = frame_type;
226 // Can't share the locals array since that is updated by the verifier.
227 if (pre_frame->locals_size() > 0) {
228 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
229 THREAD, VerificationType, pre_frame->locals_size());
230 }
231 } else {
232 offset = pre_frame->offset() + frame_type + 1;
233 locals = pre_frame->locals();
234 }
235 frame = new StackMapFrame(
236 offset, pre_frame->flags(), pre_frame->locals_size(), 0,
237 max_locals, max_stack, locals, NULL, _verifier);
238 if (first && locals != NULL) {
239 frame->copy_locals(pre_frame);
240 }
241 return frame;
242 }
243 if (frame_type < 128) {
244 // same_locals_1_stack_item_frame
245 if (first) {
246 offset = frame_type - 64;
247 // Can't share the locals array since that is updated by the verifier.
248 if (pre_frame->locals_size() > 0) {
249 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
250 THREAD, VerificationType, pre_frame->locals_size());
251 }
252 } else {
253 offset = pre_frame->offset() + frame_type - 63;
254 locals = pre_frame->locals();
255 }
256 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
257 THREAD, VerificationType, 2);
258 u2 stack_size = 1;
259 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
260 if (stack[0].is_category2()) {
261 stack[1] = stack[0].to_category2_2nd();
262 stack_size = 2;
263 }
264 check_verification_type_array_size(
265 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
266 frame = new StackMapFrame(
267 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
268 max_locals, max_stack, locals, stack, _verifier);
269 if (first && locals != NULL) {
270 frame->copy_locals(pre_frame);
271 }
272 return frame;
273 }
274
275 u2 offset_delta = _stream->get_u2(THREAD);
276
277 if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
278 // reserved frame types
279 _stream->stackmap_format_error(
280 "reserved frame type", CHECK_VERIFY_(_verifier, NULL));
281 }
282
283 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
284 // same_locals_1_stack_item_frame_extended
285 if (first) {
286 offset = offset_delta;
287 // Can't share the locals array since that is updated by the verifier.
288 if (pre_frame->locals_size() > 0) {
289 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
290 THREAD, VerificationType, pre_frame->locals_size());
291 }
292 } else {
293 offset = pre_frame->offset() + offset_delta + 1;
294 locals = pre_frame->locals();
295 }
296 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
297 THREAD, VerificationType, 2);
298 u2 stack_size = 1;
299 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
300 if (stack[0].is_category2()) {
301 stack[1] = stack[0].to_category2_2nd();
302 stack_size = 2;
303 }
304 check_verification_type_array_size(
305 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
306 frame = new StackMapFrame(
307 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
308 max_locals, max_stack, locals, stack, _verifier);
309 if (first && locals != NULL) {
310 frame->copy_locals(pre_frame);
311 }
312 return frame;
313 }
314
315 if (frame_type <= SAME_EXTENDED) {
316 // chop_frame or same_frame_extended
317 locals = pre_frame->locals();
318 int length = pre_frame->locals_size();
319 int chops = SAME_EXTENDED - frame_type;
320 int new_length = length;
321 u1 flags = pre_frame->flags();
322 if (chops != 0) {
323 new_length = chop(locals, length, chops);
324 check_verification_type_array_size(
325 new_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
326 // Recompute flags since uninitializedThis could have been chopped.
327 flags = 0;
328 for (int i=0; i<new_length; i++) {
329 if (locals[i].is_uninitialized_this()) {
330 flags |= FLAG_THIS_UNINIT;
331 break;
332 }
333 }
334 }
335 if (first) {
336 offset = offset_delta;
337 // Can't share the locals array since that is updated by the verifier.
338 if (new_length > 0) {
339 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
340 THREAD, VerificationType, new_length);
341 } else {
342 locals = NULL;
343 }
344 } else {
345 offset = pre_frame->offset() + offset_delta + 1;
346 }
347 frame = new StackMapFrame(
348 offset, flags, new_length, 0, max_locals, max_stack,
349 locals, NULL, _verifier);
350 if (first && locals != NULL) {
351 frame->copy_locals(pre_frame);
352 }
353 return frame;
354 } else if (frame_type < SAME_EXTENDED + 4) {
355 // append_frame
356 int appends = frame_type - SAME_EXTENDED;
357 int real_length = pre_frame->locals_size();
358 int new_length = real_length + appends*2;
359 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
360 VerificationType* pre_locals = pre_frame->locals();
361 int i;
362 for (i=0; i<pre_frame->locals_size(); i++) {
363 locals[i] = pre_locals[i];
364 }
365 u1 flags = pre_frame->flags();
366 for (i=0; i<appends; i++) {
367 locals[real_length] = parse_verification_type(&flags, THREAD);
368 if (locals[real_length].is_category2()) {
369 locals[real_length + 1] = locals[real_length].to_category2_2nd();
370 ++real_length;
371 }
372 ++real_length;
373 }
374 check_verification_type_array_size(
375 real_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
376 if (first) {
377 offset = offset_delta;
378 } else {
379 offset = pre_frame->offset() + offset_delta + 1;
380 }
381 frame = new StackMapFrame(
382 offset, flags, real_length, 0, max_locals,
383 max_stack, locals, NULL, _verifier);
384 return frame;
385 }
386 if (frame_type == FULL) {
387 // full_frame
388 u1 flags = 0;
389 u2 locals_size = _stream->get_u2(THREAD);
390 int real_locals_size = 0;
391 if (locals_size > 0) {
392 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
393 THREAD, VerificationType, locals_size*2);
394 }
395 int i;
396 for (i=0; i<locals_size; i++) {
397 locals[real_locals_size] = parse_verification_type(&flags, THREAD);
398 if (locals[real_locals_size].is_category2()) {
399 locals[real_locals_size + 1] =
400 locals[real_locals_size].to_category2_2nd();
401 ++real_locals_size;
402 }
403 ++real_locals_size;
404 }
405 check_verification_type_array_size(
406 real_locals_size, max_locals, CHECK_VERIFY_(_verifier, NULL));
407 u2 stack_size = _stream->get_u2(THREAD);
408 int real_stack_size = 0;
409 VerificationType* stack = NULL;
410 if (stack_size > 0) {
411 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
412 THREAD, VerificationType, stack_size*2);
413 }
414 for (i=0; i<stack_size; i++) {
415 stack[real_stack_size] = parse_verification_type(NULL, THREAD);
416 if (stack[real_stack_size].is_category2()) {
417 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
418 ++real_stack_size;
419 }
420 ++real_stack_size;
421 }
422 check_verification_type_array_size(
423 real_stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
424 if (first) {
425 offset = offset_delta;
426 } else {
427 offset = pre_frame->offset() + offset_delta + 1;
428 }
429 frame = new StackMapFrame(
430 offset, flags, real_locals_size, real_stack_size,
431 max_locals, max_stack, locals, stack, _verifier);
432 return frame;
433 }
434
435 _stream->stackmap_format_error(
436 "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), NULL));
437 return NULL;
438 }