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 }
134 }
135
136 void StackMapTable::print_on(outputStream* str) const {
137 str->indent().print_cr("StackMapTable: frame_count = %d", _frame_count);
138 str->indent().print_cr("table = { ");
139 {
140 streamIndentor si(str);
141 for (int32_t i = 0; i < _frame_count; ++i) {
142 _frame_array[i]->print_on(str);
143 }
144 }
145 str->print_cr(" }");
146 }
147
148 int32_t StackMapReader::chop(
149 VerificationType* locals, int32_t length, int32_t chops) {
150 if (locals == NULL) return -1;
151 int32_t pos = length - 1;
152 for (int32_t i=0; i<chops; i++) {
153 if (locals[pos].is_category2_2nd()) {
154 pos -= 2;
155 } else {
156 pos --;
157 }
158 if (pos<0 && i<(chops-1)) return -1;
159 }
160 return pos+1;
161 }
162
163 VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
164 u1 tag = _stream->get_u1(THREAD);
165 if (tag < (u1)ITEM_UninitializedThis) {
166 return VerificationType::from_tag(tag);
167 }
168 if (tag == ITEM_Object) {
169 u2 class_index = _stream->get_u2(THREAD);
170 int nconstants = _cp->length();
171 if ((class_index <= 0 || class_index >= nconstants) ||
172 (!_cp->tag_at(class_index).is_klass() &&
173 !_cp->tag_at(class_index).is_unresolved_klass())) {
174 _stream->stackmap_format_error("bad class index", THREAD);
175 return VerificationType::bogus_type();
176 }
177 return VerificationType::reference_type(_cp->klass_name_at(class_index));
178 }
179 if (tag == ITEM_UninitializedThis) {
180 if (flags != NULL) {
181 *flags |= FLAG_THIS_UNINIT;
182 }
183 return VerificationType::uninitialized_this_type();
184 }
185 if (tag == ITEM_Uninitialized) {
186 u2 offset = _stream->get_u2(THREAD);
187 if (offset >= _code_length ||
188 _code_data[offset] != ClassVerifier::NEW_OFFSET) {
189 _verifier->class_format_error(
190 "StackMapTable format error: bad offset for Uninitialized");
191 return VerificationType::bogus_type();
192 }
193 return VerificationType::uninitialized_type(offset);
194 }
195 _stream->stackmap_format_error("bad verification type", THREAD);
196 return VerificationType::bogus_type();
197 }
198
199 StackMapFrame* StackMapReader::next(
200 StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
201 StackMapFrame* frame;
202 int offset;
203 VerificationType* locals = NULL;
204 u1 frame_type = _stream->get_u1(THREAD);
205 if (frame_type < 64) {
206 // same_frame
207 if (first) {
208 offset = frame_type;
209 // Can't share the locals array since that is updated by the verifier.
210 if (pre_frame->locals_size() > 0) {
211 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
212 THREAD, VerificationType, pre_frame->locals_size());
213 }
214 } else {
215 offset = pre_frame->offset() + frame_type + 1;
216 locals = pre_frame->locals();
217 }
218 frame = new StackMapFrame(
219 offset, pre_frame->flags(), pre_frame->locals_size(), 0,
220 max_locals, max_stack, locals, NULL, _verifier);
221 if (first && locals != NULL) {
222 frame->copy_locals(pre_frame);
223 }
224 return frame;
225 }
226 if (frame_type < 128) {
227 // same_locals_1_stack_item_frame
228 if (first) {
229 offset = frame_type - 64;
230 // Can't share the locals array since that is updated by the verifier.
231 if (pre_frame->locals_size() > 0) {
232 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
233 THREAD, VerificationType, pre_frame->locals_size());
234 }
235 } else {
236 offset = pre_frame->offset() + frame_type - 63;
237 locals = pre_frame->locals();
238 }
239 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
240 THREAD, VerificationType, 2);
241 u2 stack_size = 1;
242 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
243 if (stack[0].is_category2()) {
244 stack[1] = stack[0].to_category2_2nd();
245 stack_size = 2;
246 }
247 check_verification_type_array_size(
248 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
249 frame = new StackMapFrame(
250 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
251 max_locals, max_stack, locals, stack, _verifier);
252 if (first && locals != NULL) {
253 frame->copy_locals(pre_frame);
254 }
255 return frame;
256 }
257
258 u2 offset_delta = _stream->get_u2(THREAD);
259
260 if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
261 // reserved frame types
262 _stream->stackmap_format_error(
263 "reserved frame type", CHECK_VERIFY_(_verifier, NULL));
264 }
265
266 if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
267 // same_locals_1_stack_item_frame_extended
268 if (first) {
269 offset = offset_delta;
270 // Can't share the locals array since that is updated by the verifier.
271 if (pre_frame->locals_size() > 0) {
272 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
273 THREAD, VerificationType, pre_frame->locals_size());
274 }
275 } else {
276 offset = pre_frame->offset() + offset_delta + 1;
277 locals = pre_frame->locals();
278 }
279 VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
280 THREAD, VerificationType, 2);
281 u2 stack_size = 1;
282 stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
283 if (stack[0].is_category2()) {
284 stack[1] = stack[0].to_category2_2nd();
285 stack_size = 2;
286 }
287 check_verification_type_array_size(
288 stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
289 frame = new StackMapFrame(
290 offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
291 max_locals, max_stack, locals, stack, _verifier);
292 if (first && locals != NULL) {
293 frame->copy_locals(pre_frame);
294 }
295 return frame;
296 }
297
298 if (frame_type <= SAME_EXTENDED) {
299 // chop_frame or same_frame_extended
300 locals = pre_frame->locals();
301 int length = pre_frame->locals_size();
302 int chops = SAME_EXTENDED - frame_type;
303 int new_length = length;
304 u1 flags = pre_frame->flags();
305 if (chops != 0) {
306 new_length = chop(locals, length, chops);
307 check_verification_type_array_size(
308 new_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
309 // Recompute flags since uninitializedThis could have been chopped.
310 flags = 0;
311 for (int i=0; i<new_length; i++) {
312 if (locals[i].is_uninitialized_this()) {
313 flags |= FLAG_THIS_UNINIT;
314 break;
315 }
316 }
317 }
318 if (first) {
319 offset = offset_delta;
320 // Can't share the locals array since that is updated by the verifier.
321 if (new_length > 0) {
322 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
323 THREAD, VerificationType, new_length);
324 } else {
325 locals = NULL;
326 }
327 } else {
328 offset = pre_frame->offset() + offset_delta + 1;
329 }
330 frame = new StackMapFrame(
331 offset, flags, new_length, 0, max_locals, max_stack,
332 locals, NULL, _verifier);
333 if (first && locals != NULL) {
334 frame->copy_locals(pre_frame);
335 }
336 return frame;
337 } else if (frame_type < SAME_EXTENDED + 4) {
338 // append_frame
339 int appends = frame_type - SAME_EXTENDED;
340 int real_length = pre_frame->locals_size();
341 int new_length = real_length + appends*2;
342 locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
343 VerificationType* pre_locals = pre_frame->locals();
344 int i;
345 for (i=0; i<pre_frame->locals_size(); i++) {
346 locals[i] = pre_locals[i];
347 }
348 u1 flags = pre_frame->flags();
349 for (i=0; i<appends; i++) {
350 locals[real_length] = parse_verification_type(&flags, THREAD);
351 if (locals[real_length].is_category2()) {
352 locals[real_length + 1] = locals[real_length].to_category2_2nd();
353 ++real_length;
354 }
355 ++real_length;
356 }
357 check_verification_type_array_size(
358 real_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
359 if (first) {
360 offset = offset_delta;
361 } else {
362 offset = pre_frame->offset() + offset_delta + 1;
363 }
364 frame = new StackMapFrame(
365 offset, flags, real_length, 0, max_locals,
366 max_stack, locals, NULL, _verifier);
367 return frame;
368 }
369 if (frame_type == FULL) {
370 // full_frame
371 u1 flags = 0;
372 u2 locals_size = _stream->get_u2(THREAD);
373 int real_locals_size = 0;
374 if (locals_size > 0) {
375 locals = NEW_RESOURCE_ARRAY_IN_THREAD(
376 THREAD, VerificationType, locals_size*2);
377 }
378 int i;
379 for (i=0; i<locals_size; i++) {
380 locals[real_locals_size] = parse_verification_type(&flags, THREAD);
381 if (locals[real_locals_size].is_category2()) {
382 locals[real_locals_size + 1] =
383 locals[real_locals_size].to_category2_2nd();
384 ++real_locals_size;
385 }
386 ++real_locals_size;
387 }
388 check_verification_type_array_size(
389 real_locals_size, max_locals, CHECK_VERIFY_(_verifier, NULL));
390 u2 stack_size = _stream->get_u2(THREAD);
391 int real_stack_size = 0;
392 VerificationType* stack = NULL;
393 if (stack_size > 0) {
394 stack = NEW_RESOURCE_ARRAY_IN_THREAD(
395 THREAD, VerificationType, stack_size*2);
396 }
397 for (i=0; i<stack_size; i++) {
398 stack[real_stack_size] = parse_verification_type(NULL, THREAD);
399 if (stack[real_stack_size].is_category2()) {
400 stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
401 ++real_stack_size;
402 }
403 ++real_stack_size;
404 }
405 check_verification_type_array_size(
406 real_stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
407 if (first) {
408 offset = offset_delta;
409 } else {
410 offset = pre_frame->offset() + offset_delta + 1;
411 }
412 frame = new StackMapFrame(
413 offset, flags, real_locals_size, real_stack_size,
414 max_locals, max_stack, locals, stack, _verifier);
415 return frame;
416 }
417
418 _stream->stackmap_format_error(
419 "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), NULL));
420 return NULL;
421 }