194
195 if (PrintMiscellaneous && (WizardMode || Verbose)) {
196 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d",
197 itable_index, s->entry_point(),
198 (int)(s->code_end() - s->entry_point()),
199 (int)(s->code_end() - __ pc()));
200 }
201 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
202 // shut the door on sizing bugs
203 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
204 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
205
206 s->set_exception_points(npe_addr, ame_addr);
207 return s;
208 }
209
210 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
211 if (is_vtable_stub) {
212 // Vtable stub size
213 return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +
214 (UseCompressedKlassPointers ? 16 : 0); // 1 leaq can be 3 bytes + 1 long
215 } else {
216 // Itable stub size
217 return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) +
218 (UseCompressedKlassPointers ? 32 : 0); // 2 leaqs
219 }
220 // In order to tune these parameters, run the JVM with VM options
221 // +PrintMiscellaneous and +WizardMode to see information about
222 // actual itable stubs. Look for lines like this:
223 // itable #1 at 0x5551212[71] left over: 3
224 // Reduce the constants so that the "left over" number is >=3
225 // for the common cases.
226 // Do not aim at a left-over number of zero, because a
227 // large vtable or itable index (>= 32) will require a 32-bit
228 // immediate displacement instead of an 8-bit one.
229 //
230 // The JVM98 app. _202_jess has a megamorphic interface call.
231 // The itable code looks like this:
232 // Decoding VtableStub itbl[1]@12
233 // mov 0x8(%rsi),%r10
234 // mov 0x198(%r10),%r11d
235 // lea 0x218(%r10,%r11,8),%r11
236 // lea 0x8(%r10),%r10
237 // mov (%r11),%rbx
238 // cmp %rbx,%rax
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194
195 if (PrintMiscellaneous && (WizardMode || Verbose)) {
196 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d",
197 itable_index, s->entry_point(),
198 (int)(s->code_end() - s->entry_point()),
199 (int)(s->code_end() - __ pc()));
200 }
201 guarantee(__ pc() <= s->code_end(), "overflowed buffer");
202 // shut the door on sizing bugs
203 int slop = 3; // 32-bit offset is this much larger than an 8-bit one
204 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset");
205
206 s->set_exception_points(npe_addr, ame_addr);
207 return s;
208 }
209
210 int VtableStub::pd_code_size_limit(bool is_vtable_stub) {
211 if (is_vtable_stub) {
212 // Vtable stub size
213 return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) +
214 (UseCompressedKlassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
215 } else {
216 // Itable stub size
217 return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) +
218 (UseCompressedKlassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0);
219 }
220 // In order to tune these parameters, run the JVM with VM options
221 // +PrintMiscellaneous and +WizardMode to see information about
222 // actual itable stubs. Look for lines like this:
223 // itable #1 at 0x5551212[71] left over: 3
224 // Reduce the constants so that the "left over" number is >=3
225 // for the common cases.
226 // Do not aim at a left-over number of zero, because a
227 // large vtable or itable index (>= 32) will require a 32-bit
228 // immediate displacement instead of an 8-bit one.
229 //
230 // The JVM98 app. _202_jess has a megamorphic interface call.
231 // The itable code looks like this:
232 // Decoding VtableStub itbl[1]@12
233 // mov 0x8(%rsi),%r10
234 // mov 0x198(%r10),%r11d
235 // lea 0x218(%r10,%r11,8),%r11
236 // lea 0x8(%r10),%r10
237 // mov (%r11),%rbx
238 // cmp %rbx,%rax
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