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hotspot/src/share/vm/classfile/stackMapTable.cpp

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+/*
+ * Copyright 2003-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_stackMapTable.cpp.incl"
+
+StackMapTable::StackMapTable(StackMapReader* reader, StackMapFrame* init_frame,
+                             u2 max_locals, u2 max_stack,
+                             char* code_data, int code_len, TRAPS) {
+  _code_length = code_len;
+  _frame_count = reader->get_frame_count();
+  if (_frame_count > 0) {
+    _frame_array = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD,
+                                                StackMapFrame*, _frame_count);
+    StackMapFrame* pre_frame = init_frame;
+    for (int32_t i = 0; i < _frame_count; i++) {
+      StackMapFrame* frame = reader->next(
+        pre_frame, i == 0, max_locals, max_stack,
+        CHECK_VERIFY(pre_frame->verifier()));
+      _frame_array[i] = frame;
+      int offset = frame->offset();
+      if (offset >= code_len || code_data[offset] == 0) {
+        frame->verifier()->verify_error("StackMapTable error: bad offset");
+        return;
+      }
+      pre_frame = frame;
+    }
+  }
+  reader->check_end(CHECK);
+}
+
+// This method is only called by method in StackMapTable.
+int StackMapTable::get_index_from_offset(int32_t offset) const {
+  int i = 0;
+  for (; i < _frame_count; i++) {
+    if (_frame_array[i]->offset() == offset) {
+      return i;
+    }
+  }
+  return i;  // frame with offset doesn't exist in the array
+}
+
+bool StackMapTable::match_stackmap(
+    StackMapFrame* frame, int32_t target,
+    bool match, bool update, TRAPS) const {
+  int index = get_index_from_offset(target);
+
+  return match_stackmap(
+    frame, target, index, match,
+    update, CHECK_VERIFY_(frame->verifier(), false));
+}
+
+// Match and/or update current_frame to the frame in stackmap table with
+// specified offset and frame index. Return true if the two frames match.
+//
+// The values of match and update are:                  _match__update_
+//
+// checking a branch target/exception handler:           true   false
+// linear bytecode verification following an
+// unconditional branch:                                 false  true
+// linear bytecode verification not following an
+// unconditional branch:                                 true   true
+bool StackMapTable::match_stackmap(
+    StackMapFrame* frame, int32_t target, int32_t frame_index,
+    bool match, bool update, TRAPS) const {
+  if (frame_index < 0 || frame_index >= _frame_count) {
+    frame->verifier()->verify_error(frame->offset(),
+      "Expecting a stackmap frame at branch target %d", target);
+    return false;
+  }
+
+  bool result = true;
+  StackMapFrame *stackmap_frame = _frame_array[frame_index];
+  if (match) {
+    // Has direct control flow from last instruction, need to match the two
+    // frames.
+    result = frame->is_assignable_to(
+      stackmap_frame, CHECK_VERIFY_(frame->verifier(), false));
+  }
+  if (update) {
+    // Use the frame in stackmap table as current frame
+    int lsize = stackmap_frame->locals_size();
+    int ssize = stackmap_frame->stack_size();
+    if (frame->locals_size() > lsize || frame->stack_size() > ssize) {
+      // Make sure unused type array items are all _bogus_type.
+      frame->reset();
+    }
+    frame->set_locals_size(lsize);
+    frame->copy_locals(stackmap_frame);
+    frame->set_stack_size(ssize);
+    frame->copy_stack(stackmap_frame);
+    frame->set_flags(stackmap_frame->flags());
+  }
+  return result;
+}
+
+void StackMapTable::check_jump_target(
+    StackMapFrame* frame, int32_t target, TRAPS) const {
+  bool match = match_stackmap(
+    frame, target, true, false, CHECK_VERIFY(frame->verifier()));
+  if (!match || (target < 0 || target >= _code_length)) {
+    frame->verifier()->verify_error(frame->offset(),
+      "Inconsistent stackmap frames at branch target %d", target);
+    return;
+  }
+  // check if uninitialized objects exist on backward branches
+  check_new_object(frame, target, CHECK_VERIFY(frame->verifier()));
+}
+
+void StackMapTable::check_new_object(
+    const StackMapFrame* frame, int32_t target, TRAPS) const {
+  if (frame->offset() > target && frame->has_new_object()) {
+    frame->verifier()->verify_error(frame->offset(),
+      "Uninitialized object exists on backward branch %d", target);
+    return;
+  }
+}
+
+#ifndef PRODUCT
+
+void StackMapTable::print() const {
+  tty->print_cr("StackMapTable: frame_count = %d", _frame_count);
+  tty->print_cr("table = { ");
+  for (int32_t i = 0; i < _frame_count; i++) {
+    _frame_array[i]->print();
+  }
+  tty->print_cr(" }");
+}
+
+#endif
+
+int32_t StackMapReader::chop(
+    VerificationType* locals, int32_t length, int32_t chops) {
+  int32_t pos = length - 1;
+  for (int32_t i=0; i<chops; i++) {
+    if (locals[pos].is_category2_2nd()) {
+      pos -= 2;
+    } else {
+      pos --;
+    }
+    if (pos<0 && i<(chops-1)) return -1;
+  }
+  return pos+1;
+}
+
+VerificationType StackMapReader::parse_verification_type(u1* flags, TRAPS) {
+  u1 tag = _stream->get_u1(THREAD);
+  if (tag < (u1)ITEM_UninitializedThis) {
+    return VerificationType::from_tag(tag);
+  }
+  if (tag == ITEM_Object) {
+    u2 class_index = _stream->get_u2(THREAD);
+    int nconstants = _cp->length();
+    if ((class_index <= 0 || class_index >= nconstants) ||
+        (!_cp->tag_at(class_index).is_klass() &&
+         !_cp->tag_at(class_index).is_unresolved_klass())) {
+      _stream->stackmap_format_error("bad class index", THREAD);
+      return VerificationType::bogus_type();
+    }
+    return VerificationType::reference_type(
+      symbolHandle(THREAD, _cp->klass_name_at(class_index)));
+  }
+  if (tag == ITEM_UninitializedThis) {
+    if (flags != NULL) {
+      *flags |= FLAG_THIS_UNINIT;
+    }
+    return VerificationType::uninitialized_this_type();
+  }
+  if (tag == ITEM_Uninitialized) {
+    u2 offset = _stream->get_u2(THREAD);
+    if (offset >= _code_length ||
+        _code_data[offset] != ClassVerifier::NEW_OFFSET) {
+      ResourceMark rm(THREAD);
+      _verifier->class_format_error(
+        "StackMapTable format error: bad offset for Uninitialized");
+      return VerificationType::bogus_type();
+    }
+    return VerificationType::uninitialized_type(offset);
+  }
+  _stream->stackmap_format_error("bad verification type", THREAD);
+  return VerificationType::bogus_type();
+}
+
+StackMapFrame* StackMapReader::next(
+    StackMapFrame* pre_frame, bool first, u2 max_locals, u2 max_stack, TRAPS) {
+  StackMapFrame* frame;
+  int offset;
+  VerificationType* locals = NULL;
+  u1 frame_type = _stream->get_u1(THREAD);
+  if (frame_type < 64) {
+    // same_frame
+    if (first) {
+      offset = frame_type;
+      // Can't share the locals array since that is updated by the verifier.
+      if (pre_frame->locals_size() > 0) {
+        locals = NEW_RESOURCE_ARRAY_IN_THREAD(
+          THREAD, VerificationType, pre_frame->locals_size());
+      }
+    } else {
+      offset = pre_frame->offset() + frame_type + 1;
+      locals = pre_frame->locals();
+    }
+    frame = new StackMapFrame(
+      offset, pre_frame->flags(), pre_frame->locals_size(), 0,
+      max_locals, max_stack, locals, NULL, _verifier);
+    if (first && locals != NULL) {
+      frame->copy_locals(pre_frame);
+    }
+    return frame;
+  }
+  if (frame_type < 128) {
+    // same_locals_1_stack_item_frame
+    if (first) {
+      offset = frame_type - 64;
+      // Can't share the locals array since that is updated by the verifier.
+      if (pre_frame->locals_size() > 0) {
+        locals = NEW_RESOURCE_ARRAY_IN_THREAD(
+          THREAD, VerificationType, pre_frame->locals_size());
+      }
+    } else {
+      offset = pre_frame->offset() + frame_type - 63;
+      locals = pre_frame->locals();
+    }
+    VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
+      THREAD, VerificationType, 2);
+    u2 stack_size = 1;
+    stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
+    if (stack[0].is_category2()) {
+      stack[1] = stack[0].to_category2_2nd();
+      stack_size = 2;
+    }
+    check_verification_type_array_size(
+      stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
+    frame = new StackMapFrame(
+      offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
+      max_locals, max_stack, locals, stack, _verifier);
+    if (first && locals != NULL) {
+      frame->copy_locals(pre_frame);
+    }
+    return frame;
+  }
+
+  u2 offset_delta = _stream->get_u2(THREAD);
+
+  if (frame_type < SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
+    // reserved frame types
+    _stream->stackmap_format_error(
+      "reserved frame type", CHECK_VERIFY_(_verifier, NULL));
+  }
+
+  if (frame_type == SAME_LOCALS_1_STACK_ITEM_EXTENDED) {
+    // same_locals_1_stack_item_frame_extended
+    if (first) {
+      offset = offset_delta;
+      // Can't share the locals array since that is updated by the verifier.
+      if (pre_frame->locals_size() > 0) {
+        locals = NEW_RESOURCE_ARRAY_IN_THREAD(
+          THREAD, VerificationType, pre_frame->locals_size());
+      }
+    } else {
+      offset = pre_frame->offset() + offset_delta + 1;
+      locals = pre_frame->locals();
+    }
+    VerificationType* stack = NEW_RESOURCE_ARRAY_IN_THREAD(
+      THREAD, VerificationType, 2);
+    u2 stack_size = 1;
+    stack[0] = parse_verification_type(NULL, CHECK_VERIFY_(_verifier, NULL));
+    if (stack[0].is_category2()) {
+      stack[1] = stack[0].to_category2_2nd();
+      stack_size = 2;
+    }
+    check_verification_type_array_size(
+      stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
+    frame = new StackMapFrame(
+      offset, pre_frame->flags(), pre_frame->locals_size(), stack_size,
+      max_locals, max_stack, locals, stack, _verifier);
+    if (first && locals != NULL) {
+      frame->copy_locals(pre_frame);
+    }
+    return frame;
+  }
+
+  if (frame_type <= SAME_EXTENDED) {
+    // chop_frame or same_frame_extended
+    locals = pre_frame->locals();
+    int length = pre_frame->locals_size();
+    int chops = SAME_EXTENDED - frame_type;
+    int new_length = length;
+    u1 flags = pre_frame->flags();
+    if (chops != 0) {
+      new_length = chop(locals, length, chops);
+      check_verification_type_array_size(
+        new_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
+      // Recompute flags since uninitializedThis could have been chopped.
+      flags = 0;
+      for (int i=0; i<new_length; i++) {
+        if (locals[i].is_uninitialized_this()) {
+          flags |= FLAG_THIS_UNINIT;
+          break;
+        }
+      }
+    }
+    if (first) {
+      offset = offset_delta;
+      // Can't share the locals array since that is updated by the verifier.
+      if (new_length > 0) {
+        locals = NEW_RESOURCE_ARRAY_IN_THREAD(
+          THREAD, VerificationType, new_length);
+      } else {
+        locals = NULL;
+      }
+    } else {
+      offset = pre_frame->offset() + offset_delta + 1;
+    }
+    frame = new StackMapFrame(
+      offset, flags, new_length, 0, max_locals, max_stack,
+      locals, NULL, _verifier);
+    if (first && locals != NULL) {
+      frame->copy_locals(pre_frame);
+    }
+    return frame;
+  } else if (frame_type < SAME_EXTENDED + 4) {
+    // append_frame
+    int appends = frame_type - SAME_EXTENDED;
+    int real_length = pre_frame->locals_size();
+    int new_length = real_length + appends*2;
+    locals = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, VerificationType, new_length);
+    VerificationType* pre_locals = pre_frame->locals();
+    int i;
+    for (i=0; i<pre_frame->locals_size(); i++) {
+      locals[i] = pre_locals[i];
+    }
+    u1 flags = pre_frame->flags();
+    for (i=0; i<appends; i++) {
+      locals[real_length] = parse_verification_type(&flags, THREAD);
+      if (locals[real_length].is_category2()) {
+        locals[real_length + 1] = locals[real_length].to_category2_2nd();
+        ++real_length;
+      }
+      ++real_length;
+    }
+    check_verification_type_array_size(
+      real_length, max_locals, CHECK_VERIFY_(_verifier, NULL));
+    if (first) {
+      offset = offset_delta;
+    } else {
+      offset = pre_frame->offset() + offset_delta + 1;
+    }
+    frame = new StackMapFrame(
+      offset, flags, real_length, 0, max_locals,
+      max_stack, locals, NULL, _verifier);
+    return frame;
+  }
+  if (frame_type == FULL) {
+    // full_frame
+    u1 flags = 0;
+    u2 locals_size = _stream->get_u2(THREAD);
+    int real_locals_size = 0;
+    if (locals_size > 0) {
+      locals = NEW_RESOURCE_ARRAY_IN_THREAD(
+        THREAD, VerificationType, locals_size*2);
+    }
+    int i;
+    for (i=0; i<locals_size; i++) {
+      locals[real_locals_size] = parse_verification_type(&flags, THREAD);
+      if (locals[real_locals_size].is_category2()) {
+        locals[real_locals_size + 1] =
+          locals[real_locals_size].to_category2_2nd();
+        ++real_locals_size;
+      }
+      ++real_locals_size;
+    }
+    check_verification_type_array_size(
+      real_locals_size, max_locals, CHECK_VERIFY_(_verifier, NULL));
+    u2 stack_size = _stream->get_u2(THREAD);
+    int real_stack_size = 0;
+    VerificationType* stack = NULL;
+    if (stack_size > 0) {
+      stack = NEW_RESOURCE_ARRAY_IN_THREAD(
+        THREAD, VerificationType, stack_size*2);
+    }
+    for (i=0; i<stack_size; i++) {
+      stack[real_stack_size] = parse_verification_type(NULL, THREAD);
+      if (stack[real_stack_size].is_category2()) {
+        stack[real_stack_size + 1] = stack[real_stack_size].to_category2_2nd();
+        ++real_stack_size;
+      }
+      ++real_stack_size;
+    }
+    check_verification_type_array_size(
+      real_stack_size, max_stack, CHECK_VERIFY_(_verifier, NULL));
+    if (first) {
+      offset = offset_delta;
+    } else {
+      offset = pre_frame->offset() + offset_delta + 1;
+    }
+    frame = new StackMapFrame(
+      offset, flags, real_locals_size, real_stack_size,
+      max_locals, max_stack, locals, stack, _verifier);
+    return frame;
+  }
+
+  _stream->stackmap_format_error(
+    "reserved frame type", CHECK_VERIFY_(pre_frame->verifier(), NULL));
+  return NULL;
+}