jdk8-mips64-public/hotspot: src/share/vm/runtime/relocator.cpp@eef07cd490d4 (annotated)

src/share/vm/runtime/relocator.cpp@eef07cd490d4 (annotated)

src/share/vm/runtime/relocator.cpp

Wed, 03 Jul 2019 20:42:37 +0800

author: aoqi
date: Wed, 03 Jul 2019 20:42:37 +0800
changeset 9637: eef07cd490d4
parent 6876: 710a3c8b516e
permissions: -rw-r--r--

Merge

 /*
  * Copyright (c) 1997, 2012, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #include "precompiled.hpp"
 #include "classfile/stackMapTableFormat.hpp"
 #include "interpreter/bytecodes.hpp"
 #include "memory/metadataFactory.hpp"
 #include "memory/oopFactory.hpp"
 #include "memory/universe.inline.hpp"
 #include "oops/oop.inline.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/relocator.hpp"
 #define MAX_METHOD_LENGTH  65535
 #define MAX_SHORT ((1 << 15) - 1)
 #define MIN_SHORT (- (1 << 15))
 // Encapsulates a code change request. There are 3 types.
 // General instruction, jump instruction, and table/lookup switches
 //
 class ChangeItem : public ResourceObj {
   int _bci;
  public:
    ChangeItem(int bci) { _bci = bci; }
    virtual bool handle_code_change(Relocator *r) = 0;
    // type info
    virtual bool is_widen()      { return false; }
    virtual bool is_jump_widen() { return false; }
    virtual bool is_switch_pad() { return false; }
    // accessors
    int bci()    { return _bci; }
    void relocate(int break_bci, int delta) { if (_bci > break_bci) { _bci += delta; } }
    virtual bool adjust(int bci, int delta) { return false; }
    // debug
    virtual void print() = 0;
 };
 class ChangeWiden : public ChangeItem {
   int              _new_ilen;    // New length of instruction at bci
   u_char*          _inst_buffer; // New bytecodes
  public:
   ChangeWiden(int bci, int new_ilen, u_char* inst_buffer) : ChangeItem(bci) {
     _new_ilen = new_ilen;
     _inst_buffer = inst_buffer;
   }
   // Callback to do instruction
   bool handle_code_change(Relocator *r) { return r->handle_widen(bci(), _new_ilen, _inst_buffer); };
   bool is_widen()              { return true; }
   void print()                 { tty->print_cr("ChangeWiden. bci: %d   New_ilen: %d", bci(), _new_ilen); }
 };
 class ChangeJumpWiden : public ChangeItem {
   int _delta;  // New length of instruction at bci
  public:
   ChangeJumpWiden(int bci, int delta) : ChangeItem(bci) { _delta = delta; }
   // Callback to do instruction
   bool handle_code_change(Relocator *r) { return r->handle_jump_widen(bci(), _delta); };
   bool is_jump_widen()         { return true; }
   // If the bci matches, adjust the delta in the change jump request.
   bool adjust(int jump_bci, int delta) {
     if (bci() == jump_bci) {
       if (_delta > 0)
         _delta += delta;
       else
         _delta -= delta;
       return true;
     }
     return false;
   }
   void print()                 { tty->print_cr("ChangeJumpWiden. bci: %d   Delta: %d", bci(), _delta); }
 };
 class ChangeSwitchPad : public ChangeItem {
   int  _padding;
   bool _is_lookup_switch;
  public:
    ChangeSwitchPad(int bci, int padding, bool is_lookup_switch) : ChangeItem(bci) {
      _padding = padding;
      _is_lookup_switch = is_lookup_switch;
    }
    // Callback to do instruction
    bool handle_code_change(Relocator *r) { return r->handle_switch_pad(bci(), _padding, _is_lookup_switch); };
    bool is_switch_pad()        { return true; }
    int  padding()              { return _padding;  }
    bool is_lookup_switch()     { return _is_lookup_switch; }
    void print()                { tty->print_cr("ChangeSwitchPad. bci: %d   Padding: %d  IsLookupSwitch: %d", bci(), _padding, _is_lookup_switch); }
 };
 //-----------------------------------------------------------------------------------------------------------
 // Relocator code
 Relocator::Relocator(methodHandle m, RelocatorListener* listener) {
   set_method(m);
   set_code_length(method()->code_size());
   set_code_array(NULL);
   // Allocate code array and copy bytecodes
   if (!expand_code_array(0)) {
     // Should have at least MAX_METHOD_LENGTH available or the verifier
     // would have failed.
     ShouldNotReachHere();
   }
   set_compressed_line_number_table(NULL);
   set_compressed_line_number_table_size(0);
   _listener = listener;
 }
 // size is the new size of the instruction at bci. Hence, if size is less than the current
 // instruction sice, we will shrink the code.
 methodHandle Relocator::insert_space_at(int bci, int size, u_char inst_buffer[], TRAPS) {
   _changes = new GrowableArray<ChangeItem*> (10);
   _changes->push(new ChangeWiden(bci, size, inst_buffer));
   if (TraceRelocator) {
     tty->print_cr("Space at: %d Size: %d", bci, size);
     _method->print();
     _method->print_codes();
     tty->print_cr("-------------------------------------------------");
   }
   if (!handle_code_changes()) return methodHandle();
     // Construct the new method
   methodHandle new_method = Method::clone_with_new_data(method(),
                               code_array(), code_length(),
                               compressed_line_number_table(),
                               compressed_line_number_table_size(),
                               CHECK_(methodHandle()));
   // Deallocate the old Method* from metadata
   ClassLoaderData* loader_data = method()->method_holder()->class_loader_data();
   loader_data->add_to_deallocate_list(method()());
     set_method(new_method);
   if (TraceRelocator) {
     tty->print_cr("-------------------------------------------------");
     tty->print_cr("new method");
     _method->print_codes();
   }
   return new_method;
 }
 bool Relocator::handle_code_changes() {
   assert(_changes != NULL, "changes vector must be initialized");
   while (!_changes->is_empty()) {
     // Inv: everything is aligned.
     ChangeItem* ci = _changes->first();
     if (TraceRelocator) {
       ci->print();
     }
     // Execute operation
     if (!ci->handle_code_change(this)) return false;
     // Shuffel items up
     for (int index = 1; index < _changes->length(); index++) {
       _changes->at_put(index-1, _changes->at(index));
     }
     _changes->pop();
   }
   return true;
 }
 bool Relocator::is_opcode_lookupswitch(Bytecodes::Code bc) {
   switch (bc) {
     case Bytecodes::_tableswitch:       return false;
     case Bytecodes::_lookupswitch:                   // not rewritten on ia64
     case Bytecodes::_fast_linearswitch:              // rewritten _lookupswitch
     case Bytecodes::_fast_binaryswitch: return true; // rewritten _lookupswitch
     default: ShouldNotReachHere();
   }
   return true; // dummy
 }
 // We need a special instruction size method, since lookupswitches and tableswitches might not be
 // properly alligned during relocation
 int Relocator::rc_instr_len(int bci) {
   Bytecodes::Code bc= code_at(bci);
   switch (bc) {
     // In the case of switch instructions, see if we have the original
     // padding recorded.
     case Bytecodes::_tableswitch:
     case Bytecodes::_lookupswitch:
     case Bytecodes::_fast_linearswitch:
     case Bytecodes::_fast_binaryswitch:
     {
       int pad = get_orig_switch_pad(bci, is_opcode_lookupswitch(bc));
       if (pad == -1) {
         return instruction_length_at(bci);
       }
       // Otherwise, depends on the switch type.
       switch (bc) {
         case Bytecodes::_tableswitch: {
           int lo = int_at(bci + 1 + pad + 4 * 1);
           int hi = int_at(bci + 1 + pad + 4 * 2);
           int n = hi - lo + 1;
           return 1 + pad + 4*(3 + n);
         }
         case Bytecodes::_lookupswitch:
         case Bytecodes::_fast_linearswitch:
         case Bytecodes::_fast_binaryswitch: {
           int npairs = int_at(bci + 1 + pad + 4 * 1);
           return 1 + pad + 4*(2 + 2*npairs);
         }
         default:
           ShouldNotReachHere();
       }
     }
   }
   return instruction_length_at(bci);
 }
 // If a change item is recorded for "pc", with type "ct", returns the
 // associated padding, else -1.
 int Relocator::get_orig_switch_pad(int bci, bool is_lookup_switch) {
   for (int k = 0; k < _changes->length(); k++) {
     ChangeItem* ci = _changes->at(k);
     if (ci->is_switch_pad()) {
       ChangeSwitchPad* csp = (ChangeSwitchPad*)ci;
       if (csp->is_lookup_switch() == is_lookup_switch && csp->bci() == bci) {
         return csp->padding();
       }
     }
   }
   return -1;
 }
 // Push a ChangeJumpWiden if it doesn't already exist on the work queue,
 // otherwise adjust the item already there by delta.  The calculation for
 // new_delta is wrong for this because it uses the offset stored in the
 // code stream itself which wasn't fixed when item was pushed on the work queue.
 void Relocator::push_jump_widen(int bci, int delta, int new_delta) {
   for (int j = 0; j < _changes->length(); j++) {
     ChangeItem* ci = _changes->at(j);
     if (ci->adjust(bci, delta)) return;
   }
   _changes->push(new ChangeJumpWiden(bci, new_delta));
 }
 // The current instruction of "c" is a jump; one of its offset starts
 // at "offset" and is a short if "isShort" is "TRUE",
 // and an integer otherwise.  If the jump crosses "breakPC", change
 // the span of the jump by "delta".
 void Relocator::change_jump(int bci, int offset, bool is_short, int break_bci, int delta) {
   int bci_delta = (is_short) ? short_at(offset) : int_at(offset);
   int targ = bci + bci_delta;
   if ((bci <= break_bci && targ >  break_bci) ||
       (bci >  break_bci && targ <= break_bci)) {
     int new_delta;
     if (bci_delta > 0)
       new_delta = bci_delta + delta;
     else
       new_delta = bci_delta - delta;
     if (is_short && ((new_delta > MAX_SHORT) || new_delta < MIN_SHORT)) {
       push_jump_widen(bci, delta, new_delta);
     } else if (is_short) {
       short_at_put(offset, new_delta);
     } else {
       int_at_put(offset, new_delta);
     }
   }
 }
 // Changes all jumps crossing "break_bci" by "delta".  May enqueue things
 // on "rc->changes"
 void Relocator::change_jumps(int break_bci, int delta) {
   int bci = 0;
   Bytecodes::Code bc;
   // Now, adjust any affected instructions.
   while (bci < code_length()) {
     switch (bc= code_at(bci)) {
       case Bytecodes::_ifeq:
       case Bytecodes::_ifne:
       case Bytecodes::_iflt:
       case Bytecodes::_ifge:
       case Bytecodes::_ifgt:
       case Bytecodes::_ifle:
       case Bytecodes::_if_icmpeq:
       case Bytecodes::_if_icmpne:
       case Bytecodes::_if_icmplt:
       case Bytecodes::_if_icmpge:
       case Bytecodes::_if_icmpgt:
       case Bytecodes::_if_icmple:
       case Bytecodes::_if_acmpeq:
       case Bytecodes::_if_acmpne:
       case Bytecodes::_ifnull:
       case Bytecodes::_ifnonnull:
       case Bytecodes::_goto:
       case Bytecodes::_jsr:
         change_jump(bci, bci+1, true, break_bci, delta);
         break;
       case Bytecodes::_goto_w:
       case Bytecodes::_jsr_w:
         change_jump(bci, bci+1, false, break_bci, delta);
         break;
       case Bytecodes::_tableswitch:
       case Bytecodes::_lookupswitch:
       case Bytecodes::_fast_linearswitch:
       case Bytecodes::_fast_binaryswitch: {
         int recPad = get_orig_switch_pad(bci, (bc != Bytecodes::_tableswitch));
         int oldPad = (recPad != -1) ? recPad : align(bci+1) - (bci+1);
         if (bci > break_bci) {
           int new_bci = bci + delta;
           int newPad = align(new_bci+1) - (new_bci+1);
           // Do we need to check the padding?
           if (newPad != oldPad) {
             if (recPad == -1) {
               _changes->push(new ChangeSwitchPad(bci, oldPad, (bc != Bytecodes::_tableswitch)));
             }
           }
         }
         // Then the rest, which depend on the kind of switch.
         switch (bc) {
           case Bytecodes::_tableswitch: {
             change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
             // We cannot use the Bytecode_tableswitch abstraction, since the padding might not be correct.
             int lo = int_at(bci + 1 + oldPad + 4 * 1);
             int hi = int_at(bci + 1 + oldPad + 4 * 2);
             int n = hi - lo + 1;
             for (int k = 0; k < n; k++) {
               change_jump(bci, bci +1 + oldPad + 4*(k+3), false, break_bci, delta);
             }
             // Special next-bci calculation here...
             bci += 1 + oldPad + (n+3)*4;
             continue;
           }
           case Bytecodes::_lookupswitch:
           case Bytecodes::_fast_linearswitch:
           case Bytecodes::_fast_binaryswitch: {
             change_jump(bci, bci +1 + oldPad, false, break_bci, delta);
             // We cannot use the Bytecode_lookupswitch abstraction, since the padding might not be correct.
             int npairs = int_at(bci + 1 + oldPad + 4 * 1);
             for (int k = 0; k < npairs; k++) {
               change_jump(bci, bci + 1 + oldPad + 4*(2 + 2*k + 1), false, break_bci, delta);
             }
             /* Special next-bci calculation here... */
             bci += 1 + oldPad + (2 + (npairs*2))*4;
             continue;
           }
           default:
             ShouldNotReachHere();
         }
       }
       default:
         break;
     }
     bci += rc_instr_len(bci);
   }
 }
 // The width of instruction at "pc" is changing by "delta".  Adjust the
 // exception table, if any, of "rc->mb".
 void Relocator::adjust_exception_table(int bci, int delta) {
   ExceptionTable table(_method());
   for (int index = 0; index < table.length(); index ++) {
     if (table.start_pc(index) > bci) {
       table.set_start_pc(index, table.start_pc(index) + delta);
       table.set_end_pc(index, table.end_pc(index) + delta);
     } else if (bci < table.end_pc(index)) {
       table.set_end_pc(index, table.end_pc(index) + delta);
     }
     if (table.handler_pc(index) > bci)
       table.set_handler_pc(index, table.handler_pc(index) + delta);
   }
 }
 // The width of instruction at "bci" is changing by "delta".  Adjust the line number table.
 void Relocator::adjust_line_no_table(int bci, int delta) {
   if (method()->has_linenumber_table()) {
     CompressedLineNumberReadStream  reader(method()->compressed_linenumber_table());
     CompressedLineNumberWriteStream writer(64);  // plenty big for most line number tables
     while (reader.read_pair()) {
       int adjustment = (reader.bci() > bci) ? delta : 0;
       writer.write_pair(reader.bci() + adjustment, reader.line());
     }
     writer.write_terminator();
     set_compressed_line_number_table(writer.buffer());
     set_compressed_line_number_table_size(writer.position());
   }
 }
 // The width of instruction at "bci" is changing by "delta".  Adjust the local variable table.
 void Relocator::adjust_local_var_table(int bci, int delta) {
   int localvariable_table_length = method()->localvariable_table_length();
   if (localvariable_table_length > 0) {
     LocalVariableTableElement* table = method()->localvariable_table_start();
     for (int i = 0; i < localvariable_table_length; i++) {
       u2 current_bci = table[i].start_bci;
       if (current_bci > bci) {
         table[i].start_bci = current_bci + delta;
       } else {
         u2 current_length = table[i].length;
         if (current_bci + current_length > bci) {
           table[i].length = current_length + delta;
         }
       }
     }
   }
 }
 // Create a new array, copying the src array but adding a hole at
 // the specified location
 static Array<u1>* insert_hole_at(ClassLoaderData* loader_data,
     size_t where, int hole_sz, Array<u1>* src) {
   Thread* THREAD = Thread::current();
   Array<u1>* dst =
       MetadataFactory::new_array<u1>(loader_data, src->length() + hole_sz, 0, CHECK_NULL);
   address src_addr = (address)src->adr_at(0);
   address dst_addr = (address)dst->adr_at(0);
   memcpy(dst_addr, src_addr, where);
   memcpy(dst_addr + where + hole_sz,
          src_addr + where, src->length() - where);
   return dst;
 }
 // The width of instruction at "bci" is changing by "delta".  Adjust the stack
 // map frames.
 void Relocator::adjust_stack_map_table(int bci, int delta) {
   if (method()->has_stackmap_table()) {
     Array<u1>* data = method()->stackmap_data();
     // The data in the array is a classfile representation of the stackmap table
     stack_map_table* sm_table =
         stack_map_table::at((address)data->adr_at(0));
     int count = sm_table->number_of_entries();
     stack_map_frame* frame = sm_table->entries();
     int bci_iter = -1;
     bool offset_adjusted = false; // only need to adjust one offset
     for (int i = 0; i < count; ++i) {
       int offset_delta = frame->offset_delta();
       bci_iter += offset_delta;
       if (!offset_adjusted && bci_iter > bci) {
         int new_offset_delta = offset_delta + delta;
         if (frame->is_valid_offset(new_offset_delta)) {
           frame->set_offset_delta(new_offset_delta);
         } else {
           assert(frame->is_same_frame() ||
                  frame->is_same_locals_1_stack_item_frame(),
                  "Frame must be one of the compressed forms");
           // The new delta exceeds the capacity of the 'same_frame' or
           // 'same_frame_1_stack_item_frame' frame types.  We need to
           // convert these frames to the extended versions, but the extended
           // version is bigger and requires more room.  So we allocate a
           // new array and copy the data, being sure to leave u2-sized hole
           // right after the 'frame_type' for the new offset field.
           //
           // We can safely ignore the reverse situation as a small delta
           // can still be used in an extended version of the frame.
           size_t frame_offset = (address)frame - (address)data->adr_at(0);
           ClassLoaderData* loader_data = method()->method_holder()->class_loader_data();
           Array<u1>* new_data = insert_hole_at(loader_data, frame_offset + 1, 2, data);
           if (new_data == NULL) {
             return; // out-of-memory?
           }
           // Deallocate old data
           MetadataFactory::free_array<u1>(loader_data, data);
           data = new_data;
           address frame_addr = (address)(data->adr_at(0) + frame_offset);
           frame = stack_map_frame::at(frame_addr);
           // Now convert the frames in place
           if (frame->is_same_frame()) {
             same_frame_extended::create_at(frame_addr, new_offset_delta);
           } else {
             same_locals_1_stack_item_extended::create_at(
               frame_addr, new_offset_delta, NULL);
             // the verification_info_type should already be at the right spot
           }
         }
         offset_adjusted = true; // needs to be done only once, since subsequent
                                 // values are offsets from the current
       }
       // The stack map frame may contain verification types, if so we need to
       // check and update any Uninitialized type's bci (no matter where it is).
       int number_of_types = frame->number_of_types();
       verification_type_info* types = frame->types();
       for (int i = 0; i < number_of_types; ++i) {
         if (types->is_uninitialized() && types->bci() > bci) {
           types->set_bci(types->bci() + delta);
         }
         types = types->next();
       }
       // Full frame has stack values too
       full_frame* ff = frame->as_full_frame();
       if (ff != NULL) {
         address eol = (address)types;
         number_of_types = ff->stack_slots(eol);
         types = ff->stack(eol);
         for (int i = 0; i < number_of_types; ++i) {
           if (types->is_uninitialized() && types->bci() > bci) {
             types->set_bci(types->bci() + delta);
           }
           types = types->next();
         }
       }
       frame = frame->next();
     }
     method()->set_stackmap_data(data); // in case it has changed
   }
 }
 bool Relocator::expand_code_array(int delta) {
   int length = MAX2(code_length() + delta, code_length() * (100+code_slop_pct()) / 100);
   if (length > MAX_METHOD_LENGTH) {
     if (delta == 0 && code_length() <= MAX_METHOD_LENGTH) {
       length = MAX_METHOD_LENGTH;
     } else {
       return false;
     }
   }
   unsigned char* new_code_array = NEW_RESOURCE_ARRAY(unsigned char, length);
   if (!new_code_array) return false;
   // Expanding current array
   if (code_array() != NULL) {
     memcpy(new_code_array, code_array(), code_length());
   } else {
     // Initial copy. Copy directly from Method*
     memcpy(new_code_array, method()->code_base(), code_length());
   }
   set_code_array(new_code_array);
   set_code_array_length(length);
   return true;
 }
 // The instruction at "bci", whose size is "ilen", is changing size by
 // "delta".  Reallocate, move code, recalculate jumps, and enqueue
 // change items as necessary.
 bool Relocator::relocate_code(int bci, int ilen, int delta) {
   int next_bci = bci + ilen;
   if (delta > 0 && code_length() + delta > code_array_length())  {
     // Expand allocated code space, if necessary.
     if (!expand_code_array(delta)) {
           return false;
     }
   }
   // We require 4-byte alignment of code arrays.
   assert(((intptr_t)code_array() & 3) == 0, "check code alignment");
   // Change jumps before doing the copying; this routine requires aligned switches.
   change_jumps(bci, delta);
   // In case we have shrunken a tableswitch/lookupswitch statement, we store the last
   // bytes that get overwritten. We have to copy the bytes after the change_jumps method
   // has been called, since it is likly to update last offset in a tableswitch/lookupswitch
   if (delta < 0) {
     assert(delta>=-3, "we cannot overwrite more than 3 bytes");
     memcpy(_overwrite, addr_at(bci + ilen + delta), -delta);
   }
   memmove(addr_at(next_bci + delta), addr_at(next_bci), code_length() - next_bci);
   set_code_length(code_length() + delta);
   // Also adjust exception tables...
   adjust_exception_table(bci, delta);
   // Line number tables...
   adjust_line_no_table(bci, delta);
   // And local variable table...
   adjust_local_var_table(bci, delta);
   // Adjust stack maps
   adjust_stack_map_table(bci, delta);
   // Relocate the pending change stack...
   for (int j = 0; j < _changes->length(); j++) {
     ChangeItem* ci = _changes->at(j);
     ci->relocate(bci, delta);
   }
   // Notify any listeners about code relocation
   notify(bci, delta, code_length());
   return true;
 }
 // relocate a general instruction. Called by ChangeWiden class
 bool Relocator::handle_widen(int bci, int new_ilen, u_char inst_buffer[]) {
   int ilen = rc_instr_len(bci);
   if (!relocate_code(bci, ilen, new_ilen - ilen))
     return false;
   // Insert new bytecode(s)
   for(int k = 0; k < new_ilen; k++) {
     code_at_put(bci + k, (Bytecodes::Code)inst_buffer[k]);
   }
   return true;
 }
 // handle jump_widen instruction. Called be ChangeJumpWiden class
 bool Relocator::handle_jump_widen(int bci, int delta) {
   int ilen = rc_instr_len(bci);
   Bytecodes::Code bc = code_at(bci);
   switch (bc) {
     case Bytecodes::_ifeq:
     case Bytecodes::_ifne:
     case Bytecodes::_iflt:
     case Bytecodes::_ifge:
     case Bytecodes::_ifgt:
     case Bytecodes::_ifle:
     case Bytecodes::_if_icmpeq:
     case Bytecodes::_if_icmpne:
     case Bytecodes::_if_icmplt:
     case Bytecodes::_if_icmpge:
     case Bytecodes::_if_icmpgt:
     case Bytecodes::_if_icmple:
     case Bytecodes::_if_acmpeq:
     case Bytecodes::_if_acmpne:
     case Bytecodes::_ifnull:
     case Bytecodes::_ifnonnull: {
       const int goto_length   = Bytecodes::length_for(Bytecodes::_goto);
       // If 'if' points to the next bytecode after goto, it's already handled.
       // it shouldn't be.
       assert (short_at(bci+1) != ilen+goto_length, "if relocation already handled");
       assert(ilen == 3, "check length");
       // Convert to 0 if <cond> goto 6
       //            3 _goto 11
       //            6 _goto_w <wide delta offset>
       //            11 <else code>
       const int goto_w_length = Bytecodes::length_for(Bytecodes::_goto_w);
       const int add_bci = goto_length + goto_w_length;
       if (!relocate_code(bci, 3, /*delta*/add_bci)) return false;
       // if bytecode points to goto_w instruction
       short_at_put(bci + 1, ilen + goto_length);
       int cbci = bci + ilen;
       // goto around
       code_at_put(cbci, Bytecodes::_goto);
       short_at_put(cbci + 1, add_bci);
       // goto_w <wide delta>
       cbci = cbci + goto_length;
       code_at_put(cbci, Bytecodes::_goto_w);
       if (delta > 0) {
         delta += 2;                 // goto_w is 2 bytes more than "if" code
       } else {
         delta -= ilen+goto_length;  // branch starts at goto_w offset
       }
       int_at_put(cbci + 1, delta);
       break;
       }
     case Bytecodes::_goto:
     case Bytecodes::_jsr:
       assert(ilen == 3, "check length");
       if (!relocate_code(bci, 3, 2)) return false;
       if (bc == Bytecodes::_goto)
         code_at_put(bci, Bytecodes::_goto_w);
       else
         code_at_put(bci, Bytecodes::_jsr_w);
       // If it's a forward jump, add 2 for the widening.
       if (delta > 0) delta += 2;
       int_at_put(bci + 1, delta);
       break;
     default: ShouldNotReachHere();
   }
   return true;
 }
 // handle lookup/table switch instructions.  Called be ChangeSwitchPad class
 bool Relocator::handle_switch_pad(int bci, int old_pad, bool is_lookup_switch) {
   int ilen = rc_instr_len(bci);
   int new_pad = align(bci+1) - (bci+1);
   int pad_delta = new_pad - old_pad;
   if (pad_delta != 0) {
     int len;
     if (!is_lookup_switch) {
       int low  = int_at(bci+1+old_pad+4);
       int high = int_at(bci+1+old_pad+8);
       len = high-low+1 + 3; // 3 for default, hi, lo.
     } else {
       int npairs = int_at(bci+1+old_pad+4);
       len = npairs*2 + 2; // 2 for default, npairs.
     }
     // Because "relocateCode" does a "changeJumps" loop,
     // which parses instructions to determine their length,
     // we need to call that before messing with the current
     // instruction.  Since it may also overwrite the current
     // instruction when moving down, remember the possibly
     // overwritten part.
     // Move the code following the instruction...
     if (!relocate_code(bci, ilen, pad_delta)) return false;
     if (pad_delta < 0) {
       // Move the shrunken instruction down.
       memmove(addr_at(bci + 1 + new_pad),
               addr_at(bci + 1 + old_pad),
               len * 4 + pad_delta);
       memmove(addr_at(bci + 1 + new_pad + len*4 + pad_delta),
               _overwrite, -pad_delta);
     } else {
       assert(pad_delta > 0, "check");
       // Move the expanded instruction up.
       memmove(addr_at(bci +1 + new_pad),
               addr_at(bci +1 + old_pad),
               len * 4);
       memset(addr_at(bci + 1), 0, new_pad); // pad must be 0
     }
   }
   return true;
 }

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/runtime/relocator.cpp@eef07cd490d4 (annotated)

src/share/vm/runtime/relocator.cpp