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src/cpu/x86/vm/vtableStubs_x86_64.cpp

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 205   __ flush();
 206 
 207   if (PrintMiscellaneous && (WizardMode || Verbose)) {
 208     tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d",
 209                   itable_index, s->entry_point(),
 210                   (int)(s->code_end() - s->entry_point()),
 211                   (int)(s->code_end() - __ pc()));
 212   }
 213   guarantee(__ pc() <= s->code_end(), "overflowed buffer");
 214   // shut the door on sizing bugs
 215   int slop = 3;  // 32-bit offset is this much larger than an 8-bit one
 216   assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
 217 
 218   s->set_exception_points(npe_addr, ame_addr);
 219   return s;
 220 }
 221 
 222 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
 223   if (is_vtable_stub) {
 224     // Vtable stub size
 225     return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +

 226            (UseCompressedClassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
 227   } else {
 228     // Itable stub size
 229     return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) +

 230            (UseCompressedClassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
 231   }
 232   // In order to tune these parameters, run the JVM with VM options
 233   // +PrintMiscellaneous and +WizardMode to see information about
 234   // actual itable stubs.  Look for lines like this:
 235   //   itable #1 at 0x5551212[71] left over: 3
 236   // Reduce the constants so that the "left over" number is >=3
 237   // for the common cases.
 238   // Do not aim at a left-over number of zero, because a
 239   // large vtable or itable index (>= 32) will require a 32-bit
 240   // immediate displacement instead of an 8-bit one.
 241   //
 242   // The JVM98 app. _202_jess has a megamorphic interface call.
 243   // The itable code looks like this:
 244   // Decoding VtableStub itbl[1]@12
 245   //   mov    0x8(%rsi),%r10
 246   //   mov    0x198(%r10),%r11d
 247   //   lea    0x218(%r10,%r11,8),%r11
 248   //   lea    0x8(%r10),%r10
 249   //   mov    (%r11),%rbx


 205   __ flush();
 206 
 207   if (PrintMiscellaneous && (WizardMode || Verbose)) {
 208     tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d",
 209                   itable_index, s->entry_point(),
 210                   (int)(s->code_end() - s->entry_point()),
 211                   (int)(s->code_end() - __ pc()));
 212   }
 213   guarantee(__ pc() <= s->code_end(), "overflowed buffer");
 214   // shut the door on sizing bugs
 215   int slop = 3;  // 32-bit offset is this much larger than an 8-bit one
 216   assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
 217 
 218   s->set_exception_points(npe_addr, ame_addr);
 219   return s;
 220 }
 221 
 222 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
 223   if (is_vtable_stub) {
 224     // Vtable stub size
 225     return (ShenandoahVerifyReadsToFromSpace ? 512 : 0) +
 226            (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +
 227            (UseCompressedClassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
 228   } else {
 229     // Itable stub size
 230     return (ShenandoahVerifyReadsToFromSpace ? 512 : 0) +
 231            (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) +
 232            (UseCompressedClassPointers ?  MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
 233   }
 234   // In order to tune these parameters, run the JVM with VM options
 235   // +PrintMiscellaneous and +WizardMode to see information about
 236   // actual itable stubs.  Look for lines like this:
 237   //   itable #1 at 0x5551212[71] left over: 3
 238   // Reduce the constants so that the "left over" number is >=3
 239   // for the common cases.
 240   // Do not aim at a left-over number of zero, because a
 241   // large vtable or itable index (>= 32) will require a 32-bit
 242   // immediate displacement instead of an 8-bit one.
 243   //
 244   // The JVM98 app. _202_jess has a megamorphic interface call.
 245   // The itable code looks like this:
 246   // Decoding VtableStub itbl[1]@12
 247   //   mov    0x8(%rsi),%r10
 248   //   mov    0x198(%r10),%r11d
 249   //   lea    0x218(%r10,%r11,8),%r11
 250   //   lea    0x8(%r10),%r10
 251   //   mov    (%r11),%rbx
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