duke@435: /*
trims@2708:  * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved.
duke@435:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435:  *
duke@435:  * This code is free software; you can redistribute it and/or modify it
duke@435:  * under the terms of the GNU General Public License version 2 only, as
duke@435:  * published by the Free Software Foundation.
duke@435:  *
duke@435:  * This code is distributed in the hope that it will be useful, but WITHOUT
duke@435:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
duke@435:  * version 2 for more details (a copy is included in the LICENSE file that
duke@435:  * accompanied this code).
duke@435:  *
duke@435:  * You should have received a copy of the GNU General Public License version
duke@435:  * 2 along with this work; if not, write to the Free Software Foundation,
duke@435:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
duke@435:  *
duke@435:  */
duke@435: 
stefank@2314: #include "precompiled.hpp"
stefank@2314: #include "classfile/stackMapTable.hpp"
stefank@2314: #include "classfile/verifier.hpp"
stefank@2314: #include "memory/resourceArea.hpp"
stefank@2314: #include "oops/oop.inline.hpp"
stefank@2314: #include "runtime/fieldType.hpp"
stefank@2314: #include "runtime/handles.inline.hpp"
duke@435: 
duke@435: StackMapTable::StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
duke@435:                              u2 max_locals, u2 max_stack,
duke@435:                              char* code_data, int code_len, TRAPS) {
duke@435:   _code_length = code_len;
duke@435:   _frame_count = reader->get_frame_count();
duke@435:   if (_frame_count > 0) {
duke@435:     _frame_array = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD,
duke@435:                                                 StackMapFrame*, _frame_count);
duke@435:     StackMapFrame* pre_frame = init_frame;
duke@435:     for (int32_t i = 0; i < _frame_count; i++) {
duke@435:       StackMapFrame* frame = reader->next(
duke@435:         pre_frame, i == 0, max_locals, max_stack,
duke@435:         CHECK_VERIFY(pre_frame->verifier()));
duke@435:       _frame_array[i] = frame;
duke@435:       int offset = frame->offset();
duke@435:       if (offset >= code_len || code_data[offset] == 0) {
duke@435:         frame->verifier()->verify_error("StackMapTable error: bad offset");
duke@435:         return;
duke@435:       }
duke@435:       pre_frame = frame;
duke@435:     }
duke@435:   }
duke@435:   reader->check_end(CHECK);
duke@435: }
duke@435: 
duke@435: // This method is only called by method in StackMapTable.
duke@435: int StackMapTable::get_index_from_offset(int32_t offset) const {
duke@435:   int i = 0;
duke@435:   for (; i < _frame_count; i++) {
duke@435:     if (_frame_array[i]->offset() == offset) {
duke@435:       return i;
duke@435:     }
duke@435:   }
duke@435:   return i;  // frame with offset doesn't exist in the array
duke@435: }
duke@435: 
duke@435: bool StackMapTable::match_stackmap(
duke@435:     StackMapFrame* frame, int32_t target,
duke@435:     bool match, bool update, TRAPS) const {
duke@435:   int index = get_index_from_offset(target);
duke@435: 
duke@435:   return match_stackmap(
duke@435:     frame, target, index, match,
duke@435:     update, CHECK_VERIFY_(frame->verifier(), false));
duke@435: }
duke@435: 
duke@435: // Match and/or update current_frame to the frame in stackmap table with
duke@435: // specified offset and frame index. Return true if the two frames match.
duke@435: //
duke@435: // The values of match and update are:                  _match__update_
duke@435: //
duke@435: // checking a branch target/exception handler:           true   false
duke@435: // linear bytecode verification following an
duke@435: // unconditional branch:                                 false  true
duke@435: // linear bytecode verification not following an
duke@435: // unconditional branch:                                 true   true
duke@435: bool StackMapTable::match_stackmap(
duke@435:     StackMapFrame* frame, int32_t target, int32_t frame_index,
duke@435:     bool match, bool update, TRAPS) const {
duke@435:   if (frame_index < 0 || frame_index >= _frame_count) {
duke@435:     frame->verifier()->verify_error(frame->offset(),
duke@435:       "Expecting a stackmap frame at branch target %d", target);
duke@435:     return false;
duke@435:   }
duke@435: 
duke@435:   bool result = true;
duke@435:   StackMapFrame *stackmap_frame = _frame_array[frame_index];
duke@435:   if (match) {
kamg@2754:     // when checking handler target, match == true && update == false
kamg@2754:     bool is_exception_handler = !update;
duke@435:     // Has direct control flow from last instruction, need to match the two
duke@435:     // frames.
duke@435:     result = frame->is_assignable_to(
kamg@2754:       stackmap_frame, is_exception_handler,
kamg@2754:       CHECK_VERIFY_(frame->verifier(), false));
duke@435:   }
duke@435:   if (update) {
duke@435:     // Use the frame in stackmap table as current frame
duke@435:     int lsize = stackmap_frame->locals_size();
duke@435:     int ssize = stackmap_frame->stack_size();
duke@435:     if (frame->locals_size() > lsize || frame->stack_size() > ssize) {
duke@435:       // Make sure unused type array items are all _bogus_type.
duke@435:       frame->reset();
duke@435:     }
duke@435:     frame->set_locals_size(lsize);
duke@435:     frame->copy_locals(stackmap_frame);
duke@435:     frame->set_stack_size(ssize);
duke@435:     frame->copy_stack(stackmap_frame);
duke@435:     frame->set_flags(stackmap_frame->flags());
duke@435:   }
duke@435:   return result;
duke@435: }
duke@435: 
duke@435: void StackMapTable::check_jump_target(
duke@435:     StackMapFrame* frame, int32_t target, TRAPS) const {
duke@435:   bool match = match_stackmap(
duke@435:     frame, target, true, false, CHECK_VERIFY(frame->verifier()));
duke@435:   if (!match || (target < 0 || target >= _code_length)) {
duke@435:     frame->verifier()->verify_error(frame->offset(),
duke@435:       "Inconsistent stackmap frames at branch target %d", target);
duke@435:     return;
duke@435:   }
duke@435:   // check if uninitialized objects exist on backward branches
duke@435:   check_new_object(frame, target, CHECK_VERIFY(frame->verifier()));
duke@435: }
duke@435: 
duke@435: void StackMapTable::check_new_object(
duke@435:     const StackMapFrame* frame, int32_t target, TRAPS) const {
duke@435:   if (frame->offset() > target && frame->has_new_object()) {
duke@435:     frame->verifier()->verify_error(frame->offset(),
duke@435:       "Uninitialized object exists on backward branch %d", target);
duke@435:     return;
duke@435:   }
duke@435: }
duke@435: 
duke@435: #ifndef PRODUCT
duke@435: 
duke@435: void StackMapTable::print() const {
duke@435:   tty->print_cr("StackMapTable: frame_count = %d", _frame_count);
duke@435:   tty->print_cr("table = { ");
duke@435:   for (int32_t i = 0; i < _frame_count; i++) {
duke@435:     _frame_array[i]->print();
duke@435:   }
duke@435:   tty->print_cr(" }");
duke@435: }
duke@435: 
duke@435: #endif
duke@435: 
duke@435: int32_t StackMapReader::chop(
duke@435:     VerificationType* locals, int32_t length, int32_t chops) {
kamg@2124:   if (locals == NULL) return -1;
duke@435:   int32_t pos = length - 1;
duke@435:   for (int32_t i=0; i<chops; i++) {
duke@435:     if (locals[pos].is_category2_2nd()) {
duke@435:       pos -= 2;
duke@435:     } else {
duke@435:       pos --;
duke@435:     }
duke@435:     if (pos<0 && i<(chops-1)) return -1;
duke@435:   }
duke@435:   return pos+1;
duke@435: }
duke@435: 
duke@435: VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
duke@435:   u1 tag = _stream->get_u1(THREAD);
duke@435:   if (tag < (u1)ITEM_UninitializedThis) {
duke@435:     return VerificationType::from_tag(tag);
duke@435:   }
duke@435:   if (tag == ITEM_Object) {
duke@435:     u2 class_index = _stream->get_u2(THREAD);
duke@435:     int nconstants = _cp->length();
duke@435:     if ((class_index <= 0 || class_index >= nconstants) ||
duke@435:         (!_cp->tag_at(class_index).is_klass() &&
duke@435:          !_cp->tag_at(class_index).is_unresolved_klass())) {
duke@435:       _stream->stackmap_format_error("bad class index", THREAD);
duke@435:       return VerificationType::bogus_type();
duke@435:     }
coleenp@2497:     return VerificationType::reference_type(_cp->klass_name_at(class_index));
duke@435:   }
duke@435:   if (tag == ITEM_UninitializedThis) {
duke@435:     if (flags != NULL) {
duke@435:       *flags |= FLAG_THIS_UNINIT;
duke@435:     }
duke@435:     return VerificationType::uninitialized_this_type();
duke@435:   }
duke@435:   if (tag == ITEM_Uninitialized) {
duke@435:     u2 offset = _stream->get_u2(THREAD);
duke@435:     if (offset >= _code_length ||
duke@435:         _code_data[offset] != ClassVerifier::NEW_OFFSET) {
duke@435:       ResourceMark rm(THREAD);
duke@435:       _verifier->class_format_error(
duke@435:         "StackMapTable format error: bad offset for Uninitialized");
duke@435:       return VerificationType::bogus_type();
duke@435:     }
duke@435:     return VerificationType::uninitialized_type(offset);
duke@435:   }
duke@435:   _stream->stackmap_format_error("bad verification type", THREAD);
duke@435:   return VerificationType::bogus_type();
duke@435: }
duke@435: 
duke@435: StackMapFrame* StackMapReader::next(
duke@435:     StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
duke@435:   StackMapFrame* frame;
duke@435:   int offset;
duke@435:   VerificationType* locals = NULL;
duke@435:   u1 frame_type = _stream->get_u1(THREAD);
duke@435:   if (frame_type < 64) {
duke@435:     // same_frame
duke@435:     if (first) {
duke@435:       offset = frame_type;
duke@435:       // Can't share the locals array since that is updated by the verifier.
duke@435:       if (pre_frame->locals_size() > 0) {
duke@435:         locals = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:           THREAD, VerificationType, pre_frame->locals_size());
duke@435:       }
duke@435:     } else {
duke@435:       offset = pre_frame->offset() + frame_type + 1;
duke@435:       locals = pre_frame->locals();
duke@435:     }
duke@435:     frame = new StackMapFrame(
duke@435:       offset, pre_frame->flags(), pre_frame->locals_size(), 0,
duke@435:       max_locals, max_stack, locals, NULL, _verifier);
duke@435:     if (first && locals != NULL) {
duke@435:       frame->copy_locals(pre_frame);
duke@435:     }
duke@435:     return frame;
duke@435:   }
duke@435:   if (frame_type < 128) {
duke@435:     // same_locals_1_stack_item_frame
duke@435:     if (first) {
duke@435:       offset = frame_type - 64;
duke@435:       // Can't share the locals array since that is updated by the verifier.
duke@435:       if (pre_frame->locals_size() > 0) {
duke@435:         locals = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:           THREAD, VerificationType, pre_frame->locals_size());
duke@435:       }
duke@435:     } else {
duke@435:       offset = pre_frame->offset() + frame_type - 63;
duke@435:       locals = pre_frame->locals();
duke@435:     }
duke@435:     VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:       THREAD, VerificationType, 2);
duke@435:     u2 stack_size = 1;
duke@435:     stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
duke@435:     if (stack[0].is_category2()) {
duke@435:       stack[1] = stack[0].to_category2_2nd();
duke@435:       stack_size = 2;
duke@435:     }
duke@435:     check_verification_type_array_size(
duke@435:       stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
duke@435:     frame = new StackMapFrame(
duke@435:       offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
duke@435:       max_locals, max_stack, locals, stack, _verifier);
duke@435:     if (first && locals != NULL) {
duke@435:       frame->copy_locals(pre_frame);
duke@435:     }
duke@435:     return frame;
duke@435:   }
duke@435: 
duke@435:   u2 offset_delta = _stream->get_u2(THREAD);
duke@435: 
duke@435:   if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
duke@435:     // reserved frame types
duke@435:     _stream->stackmap_format_error(
duke@435:       "reserved frame type", CHECK_VERIFY_(_verifier, NULL));
duke@435:   }
duke@435: 
duke@435:   if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
duke@435:     // same_locals_1_stack_item_frame_extended
duke@435:     if (first) {
duke@435:       offset = offset_delta;
duke@435:       // Can't share the locals array since that is updated by the verifier.
duke@435:       if (pre_frame->locals_size() > 0) {
duke@435:         locals = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:           THREAD, VerificationType, pre_frame->locals_size());
duke@435:       }
duke@435:     } else {
duke@435:       offset = pre_frame->offset() + offset_delta + 1;
duke@435:       locals = pre_frame->locals();
duke@435:     }
duke@435:     VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:       THREAD, VerificationType, 2);
duke@435:     u2 stack_size = 1;
duke@435:     stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
duke@435:     if (stack[0].is_category2()) {
duke@435:       stack[1] = stack[0].to_category2_2nd();
duke@435:       stack_size = 2;
duke@435:     }
duke@435:     check_verification_type_array_size(
duke@435:       stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
duke@435:     frame = new StackMapFrame(
duke@435:       offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
duke@435:       max_locals, max_stack, locals, stack, _verifier);
duke@435:     if (first && locals != NULL) {
duke@435:       frame->copy_locals(pre_frame);
duke@435:     }
duke@435:     return frame;
duke@435:   }
duke@435: 
duke@435:   if (frame_type <= SAME_EXTENDED) {
duke@435:     // chop_frame or same_frame_extended
duke@435:     locals = pre_frame->locals();
duke@435:     int length = pre_frame->locals_size();
duke@435:     int chops = SAME_EXTENDED - frame_type;
duke@435:     int new_length = length;
duke@435:     u1 flags = pre_frame->flags();
duke@435:     if (chops != 0) {
duke@435:       new_length = chop(locals, length, chops);
duke@435:       check_verification_type_array_size(
duke@435:         new_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
duke@435:       // Recompute flags since uninitializedThis could have been chopped.
duke@435:       flags = 0;
duke@435:       for (int i=0; i<new_length; i++) {
duke@435:         if (locals[i].is_uninitialized_this()) {
duke@435:           flags |= FLAG_THIS_UNINIT;
duke@435:           break;
duke@435:         }
duke@435:       }
duke@435:     }
duke@435:     if (first) {
duke@435:       offset = offset_delta;
duke@435:       // Can't share the locals array since that is updated by the verifier.
duke@435:       if (new_length > 0) {
duke@435:         locals = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:           THREAD, VerificationType, new_length);
duke@435:       } else {
duke@435:         locals = NULL;
duke@435:       }
duke@435:     } else {
duke@435:       offset = pre_frame->offset() + offset_delta + 1;
duke@435:     }
duke@435:     frame = new StackMapFrame(
duke@435:       offset, flags, new_length, 0, max_locals, max_stack,
duke@435:       locals, NULL, _verifier);
duke@435:     if (first && locals != NULL) {
duke@435:       frame->copy_locals(pre_frame);
duke@435:     }
duke@435:     return frame;
duke@435:   } else if (frame_type < SAME_EXTENDED + 4) {
duke@435:     // append_frame
duke@435:     int appends = frame_type - SAME_EXTENDED;
duke@435:     int real_length = pre_frame->locals_size();
duke@435:     int new_length = real_length + appends*2;
duke@435:     locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
duke@435:     VerificationType* pre_locals = pre_frame->locals();
duke@435:     int i;
duke@435:     for (i=0; i<pre_frame->locals_size(); i++) {
duke@435:       locals[i] = pre_locals[i];
duke@435:     }
duke@435:     u1 flags = pre_frame->flags();
duke@435:     for (i=0; i<appends; i++) {
duke@435:       locals[real_length] = parse_verification_type(&flags, THREAD);
duke@435:       if (locals[real_length].is_category2()) {
duke@435:         locals[real_length + 1] = locals[real_length].to_category2_2nd();
duke@435:         ++real_length;
duke@435:       }
duke@435:       ++real_length;
duke@435:     }
duke@435:     check_verification_type_array_size(
duke@435:       real_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
duke@435:     if (first) {
duke@435:       offset = offset_delta;
duke@435:     } else {
duke@435:       offset = pre_frame->offset() + offset_delta + 1;
duke@435:     }
duke@435:     frame = new StackMapFrame(
duke@435:       offset, flags, real_length, 0, max_locals,
duke@435:       max_stack, locals, NULL, _verifier);
duke@435:     return frame;
duke@435:   }
duke@435:   if (frame_type == FULL) {
duke@435:     // full_frame
duke@435:     u1 flags = 0;
duke@435:     u2 locals_size = _stream->get_u2(THREAD);
duke@435:     int real_locals_size = 0;
duke@435:     if (locals_size > 0) {
duke@435:       locals = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:         THREAD, VerificationType, locals_size*2);
duke@435:     }
duke@435:     int i;
duke@435:     for (i=0; i<locals_size; i++) {
duke@435:       locals[real_locals_size] = parse_verification_type(&flags, THREAD);
duke@435:       if (locals[real_locals_size].is_category2()) {
duke@435:         locals[real_locals_size + 1] =
duke@435:           locals[real_locals_size].to_category2_2nd();
duke@435:         ++real_locals_size;
duke@435:       }
duke@435:       ++real_locals_size;
duke@435:     }
duke@435:     check_verification_type_array_size(
duke@435:       real_locals_size, max_locals, CHECK_VERIFY_(_verifier, NULL));
duke@435:     u2 stack_size = _stream->get_u2(THREAD);
duke@435:     int real_stack_size = 0;
duke@435:     VerificationType* stack = NULL;
duke@435:     if (stack_size > 0) {
duke@435:       stack = NEW_RESOURCE_ARRAY_IN_THREAD(
duke@435:         THREAD, VerificationType, stack_size*2);
duke@435:     }
duke@435:     for (i=0; i<stack_size; i++) {
duke@435:       stack[real_stack_size] = parse_verification_type(NULL, THREAD);
duke@435:       if (stack[real_stack_size].is_category2()) {
duke@435:         stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
duke@435:         ++real_stack_size;
duke@435:       }
duke@435:       ++real_stack_size;
duke@435:     }
duke@435:     check_verification_type_array_size(
duke@435:       real_stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
duke@435:     if (first) {
duke@435:       offset = offset_delta;
duke@435:     } else {
duke@435:       offset = pre_frame->offset() + offset_delta + 1;
duke@435:     }
duke@435:     frame = new StackMapFrame(
duke@435:       offset, flags, real_locals_size, real_stack_size,
duke@435:       max_locals, max_stack, locals, stack, _verifier);
duke@435:     return frame;
duke@435:   }
duke@435: 
duke@435:   _stream->stackmap_format_error(
duke@435:     "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), NULL));
duke@435:   return NULL;
duke@435: }