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