1 /*
   2  * Copyright (c) 1998, 2019, 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 "code/exceptionHandlerTable.hpp"
  27 #include "code/nmethod.hpp"
  28 #include "memory/allocation.inline.hpp"
  29 
  30 void ExceptionHandlerTable::add_entry(HandlerTableEntry entry) {
  31   _nesting.check();
  32   if (_length >= _size) {
  33     // not enough space => grow the table (amortized growth, double its size)
  34     guarantee(_size > 0, "no space allocated => cannot grow the table since it is part of nmethod");
  35     int new_size = _size * 2;
  36     _table = REALLOC_RESOURCE_ARRAY(HandlerTableEntry, _table, _size, new_size);
  37     _size = new_size;
  38   }
  39   assert(_length < _size, "sanity check");
  40   _table[_length++] = entry;
  41 }
  42 
  43 
  44 HandlerTableEntry* ExceptionHandlerTable::subtable_for(int catch_pco) const {
  45   int i = 0;
  46   while (i < _length) {
  47     HandlerTableEntry* t = _table + i;
  48     if (t->pco() == catch_pco) {
  49       // found subtable matching the catch_pco
  50       return t;
  51     } else {
  52       // advance to next subtable
  53       i += t->len() + 1; // +1 for header
  54     }
  55   }
  56   return NULL;
  57 }
  58 
  59 
  60 ExceptionHandlerTable::ExceptionHandlerTable(int initial_size) {
  61   guarantee(initial_size > 0, "initial size must be > 0");
  62   _table  = NEW_RESOURCE_ARRAY(HandlerTableEntry, initial_size);
  63   _length = 0;
  64   _size   = initial_size;
  65 }
  66 
  67 
  68 ExceptionHandlerTable::ExceptionHandlerTable(const CompiledMethod* cm) {
  69   _table  = (HandlerTableEntry*)cm->handler_table_begin();
  70   _length = cm->handler_table_size() / sizeof(HandlerTableEntry);
  71   _size   = 0; // no space allocated by ExeptionHandlerTable!
  72 }
  73 
  74 
  75 void ExceptionHandlerTable::add_subtable(
  76   int                 catch_pco,
  77   GrowableArray<intptr_t>* handler_bcis,
  78   GrowableArray<intptr_t>* scope_depths_from_top_scope,
  79   GrowableArray<intptr_t>* handler_pcos
  80 ) {
  81   assert(subtable_for(catch_pco) == NULL, "catch handlers for this catch_pco added twice");
  82   assert(handler_bcis->length() == handler_pcos->length(), "bci & pc table have different length");
  83   assert(scope_depths_from_top_scope == NULL || handler_bcis->length() == scope_depths_from_top_scope->length(), "bci & scope_depths table have different length");
  84   if (handler_bcis->length() > 0) {
  85     // add subtable header
  86     add_entry(HandlerTableEntry(handler_bcis->length(), catch_pco, 0));
  87     // add individual entries
  88     for (int i = 0; i < handler_bcis->length(); i++) {
  89       intptr_t scope_depth = 0;
  90       if (scope_depths_from_top_scope != NULL) {
  91         scope_depth = scope_depths_from_top_scope->at(i);
  92       }
  93       add_entry(HandlerTableEntry(handler_bcis->at(i), handler_pcos->at(i), scope_depth));
  94       assert(entry_for(catch_pco, handler_bcis->at(i), scope_depth)->pco() == handler_pcos->at(i), "entry not added correctly (1)");
  95       assert(entry_for(catch_pco, handler_bcis->at(i), scope_depth)->scope_depth() == scope_depth, "entry not added correctly (2)");
  96     }
  97   }
  98 }
  99 
 100 
 101 void ExceptionHandlerTable::copy_to(CompiledMethod* cm) {
 102   assert(size_in_bytes() == cm->handler_table_size(), "size of space allocated in compiled method incorrect");
 103   copy_bytes_to(cm->handler_table_begin());
 104 }
 105 
 106 void ExceptionHandlerTable::copy_bytes_to(address addr) {
 107   memmove(addr, _table, size_in_bytes());
 108 }
 109 
 110 HandlerTableEntry* ExceptionHandlerTable::entry_for(int catch_pco, int handler_bci, int scope_depth) const {
 111   HandlerTableEntry* t = subtable_for(catch_pco);
 112   if (t != NULL) {
 113     int l = t->len();
 114     while (l-- > 0) {
 115       t++;
 116       if (t->bci() == handler_bci && t->scope_depth() == scope_depth) return t;
 117     }
 118   }
 119   return NULL;
 120 }
 121 
 122 
 123 void ExceptionHandlerTable::print_subtable(HandlerTableEntry* t) const {
 124   int l = t->len();
 125   tty->print_cr("catch_pco = %d (%d entries)", t->pco(), l);
 126   while (l-- > 0) {
 127     t++;
 128     tty->print_cr("  bci %d at scope depth %d -> pco %d", t->bci(), t->scope_depth(), t->pco());
 129   }
 130 }
 131 
 132 
 133 void ExceptionHandlerTable::print() const {
 134   tty->print_cr("ExceptionHandlerTable (size = %d bytes)", size_in_bytes());
 135   int i = 0;
 136   while (i < _length) {
 137     HandlerTableEntry* t = _table + i;
 138     print_subtable(t);
 139     // advance to next subtable
 140     i += t->len() + 1; // +1 for header
 141   }
 142 }
 143 
 144 void ExceptionHandlerTable::print_subtable_for(int catch_pco) const {
 145   HandlerTableEntry* subtable = subtable_for(catch_pco);
 146 
 147   if( subtable != NULL ) { print_subtable( subtable ); }
 148 }
 149 
 150 // ----------------------------------------------------------------------------
 151 // Implicit null exception tables.  Maps an exception PC offset to a
 152 // continuation PC offset.  During construction it's a variable sized
 153 // array with a max size and current length.  When stored inside an
 154 // nmethod a zero length table takes no space.  This is detected by
 155 // nul_chk_table_size() == 0.  Otherwise the table has a length word
 156 // followed by pairs of <excp-offset, const-offset>.
 157 void ImplicitExceptionTable::set_size( uint size ) {
 158   _size = size;
 159   _data = NEW_RESOURCE_ARRAY(implicit_null_entry, (size*2));
 160   _len = 0;
 161 }
 162 
 163 void ImplicitExceptionTable::append( uint exec_off, uint cont_off ) {
 164   assert( (sizeof(implicit_null_entry) >= 4) || (exec_off < 65535), "" );
 165   assert( (sizeof(implicit_null_entry) >= 4) || (cont_off < 65535), "" );
 166   uint l = len();
 167   if (l == _size) {
 168     uint old_size_in_elements = _size*2;
 169     if (_size == 0) _size = 4;
 170     _size *= 2;
 171     uint new_size_in_elements = _size*2;
 172     _data = REALLOC_RESOURCE_ARRAY(uint, _data, old_size_in_elements, new_size_in_elements);
 173   }
 174   *(adr(l)  ) = exec_off;
 175   *(adr(l)+1) = cont_off;
 176   _len = l+1;
 177 };
 178 
 179 uint ImplicitExceptionTable::continuation_offset( uint exec_off ) const {
 180   uint l = len();
 181   for( uint i=0; i<l; i++ )
 182     if( *adr(i) == exec_off )
 183       return *(adr(i)+1);
 184   return 0;                     // Failed to find any execption offset
 185 }
 186 
 187 void ImplicitExceptionTable::print(address base) const {
 188   const uint n = len();
 189   if (n > 0) {
 190     const uint items_per_line = 3;
 191     uint i;
 192     tty->print_cr("ImplicitExceptionTable (size = %d entries, %d bytes):", n, size_in_bytes());
 193     tty->print("{");
 194     for (i = 0; i < n; i++) {
 195       if (i%items_per_line == 0) {
 196         tty->cr();
 197         tty->fill_to(3);
 198       }
 199       tty->print("< " INTPTR_FORMAT ", " INTPTR_FORMAT " > ", p2i(base + *adr(i)), p2i(base + *(adr(i)+1)));
 200     }
 201     tty->bol();
 202     tty->print_cr("}");
 203   } else {
 204     tty->print_cr("ImplicitExceptionTable is empty");
 205   }
 206 }
 207 
 208 ImplicitExceptionTable::ImplicitExceptionTable(const CompiledMethod* nm) {
 209   if (nm->nul_chk_table_size() == 0) {
 210     _len = 0;
 211     _data = NULL;
 212   } else {
 213     // the first word is the length if non-zero, so read it out and
 214     // skip to the next word to get the table.
 215     _data  = (implicit_null_entry*)nm->nul_chk_table_begin();
 216     _len = _data[0];
 217     _data++;
 218   }
 219   _size = len();
 220   assert(size_in_bytes() <= nm->nul_chk_table_size(), "size of space allocated in nmethod incorrect");
 221 }
 222 
 223 void ImplicitExceptionTable::copy_to( nmethod* nm ) {
 224   copy_bytes_to(nm->nul_chk_table_begin(), nm->nul_chk_table_size());
 225 }
 226 
 227 void ImplicitExceptionTable::copy_bytes_to(address addr, int size) {
 228   assert(size_in_bytes() <= size, "size of space allocated in nmethod incorrect");
 229   if (len() != 0) {
 230     implicit_null_entry* nmdata = (implicit_null_entry*)addr;
 231     // store the length in the first uint
 232     nmdata[0] = _len;
 233     nmdata++;
 234     // copy the table after the length
 235     memmove( nmdata, _data, 2 * len() * sizeof(implicit_null_entry));
 236   } else {
 237     // zero length table takes zero bytes
 238     assert(size_in_bytes() == 0, "bad size");
 239     assert(size == 0, "bad size");
 240   }
 241 }
 242 
 243 void ImplicitExceptionTable::verify(nmethod *nm) const {
 244   for (uint i = 0; i < len(); i++) {
 245      if ((*adr(i) > (unsigned int)nm->insts_size()) ||
 246          (*(adr(i)+1) > (unsigned int)nm->insts_size()))
 247        fatal("Invalid offset in ImplicitExceptionTable at " PTR_FORMAT, p2i(_data));
 248   }
 249 }