1 /* 2 * Copyright (c) 2003, 2010, 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 "incls/_precompiled.incl" 26 #include "incls/_vtableStubs_x86_64.cpp.incl" 27 28 // machine-dependent part of VtableStubs: create VtableStub of correct size and 29 // initialize its code 30 31 #define __ masm-> 32 33 #ifndef PRODUCT 34 extern "C" void bad_compiled_vtable_index(JavaThread* thread, 35 oop receiver, 36 int index); 37 #endif 38 39 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) { 40 const int amd64_code_length = VtableStub::pd_code_size_limit(true); 41 VtableStub* s = new(amd64_code_length) VtableStub(true, vtable_index); 42 ResourceMark rm; 43 CodeBuffer cb(s->entry_point(), amd64_code_length); 44 MacroAssembler* masm = new MacroAssembler(&cb); 45 46 #ifndef PRODUCT 47 if (CountCompiledCalls) { 48 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 49 } 50 #endif 51 52 // get receiver (need to skip return address on top of stack) 53 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 54 55 // Free registers (non-args) are rax, rbx 56 57 // get receiver klass 58 address npe_addr = __ pc(); 59 __ load_klass(rax, j_rarg0); 60 61 // compute entry offset (in words) 62 int entry_offset = 63 instanceKlass::vtable_start_offset() + vtable_index * vtableEntry::size(); 64 65 #ifndef PRODUCT 66 if (DebugVtables) { 67 Label L; 68 // check offset vs vtable length 69 __ cmpl(Address(rax, instanceKlass::vtable_length_offset() * wordSize), 70 vtable_index * vtableEntry::size()); 71 __ jcc(Assembler::greater, L); 72 __ movl(rbx, vtable_index); 73 __ call_VM(noreg, 74 CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx); 75 __ bind(L); 76 } 77 #endif // PRODUCT 78 79 // load methodOop and target address 80 const Register method = rbx; 81 82 __ movptr(method, Address(rax, 83 entry_offset * wordSize + 84 vtableEntry::method_offset_in_bytes())); 85 if (DebugVtables) { 86 Label L; 87 __ cmpptr(method, (int32_t)NULL_WORD); 88 __ jcc(Assembler::equal, L); 89 __ cmpptr(Address(method, methodOopDesc::from_compiled_offset()), (int32_t)NULL_WORD); 90 __ jcc(Assembler::notZero, L); 91 __ stop("Vtable entry is NULL"); 92 __ bind(L); 93 } 94 // rax: receiver klass 95 // rbx: methodOop 96 // rcx: receiver 97 address ame_addr = __ pc(); 98 __ jmp( Address(rbx, methodOopDesc::from_compiled_offset())); 99 100 __ flush(); 101 102 if (PrintMiscellaneous && (WizardMode || Verbose)) { 103 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d", 104 vtable_index, s->entry_point(), 105 (int)(s->code_end() - s->entry_point()), 106 (int)(s->code_end() - __ pc())); 107 } 108 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 109 // shut the door on sizing bugs 110 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 111 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 112 113 s->set_exception_points(npe_addr, ame_addr); 114 return s; 115 } 116 117 118 VtableStub* VtableStubs::create_itable_stub(int itable_index) { 119 // Note well: pd_code_size_limit is the absolute minimum we can get 120 // away with. If you add code here, bump the code stub size 121 // returned by pd_code_size_limit! 122 const int amd64_code_length = VtableStub::pd_code_size_limit(false); 123 VtableStub* s = new(amd64_code_length) VtableStub(false, itable_index); 124 ResourceMark rm; 125 CodeBuffer cb(s->entry_point(), amd64_code_length); 126 MacroAssembler* masm = new MacroAssembler(&cb); 127 128 #ifndef PRODUCT 129 if (CountCompiledCalls) { 130 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 131 } 132 #endif 133 134 // Entry arguments: 135 // rax: Interface 136 // j_rarg0: Receiver 137 138 // Free registers (non-args) are rax (interface), rbx 139 140 // get receiver (need to skip return address on top of stack) 141 142 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 143 // get receiver klass (also an implicit null-check) 144 address npe_addr = __ pc(); 145 146 // Most registers are in use; we'll use rax, rbx, r10, r11 147 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them) 148 __ load_klass(r10, j_rarg0); 149 150 // If we take a trap while this arg is on the stack we will not 151 // be able to walk the stack properly. This is not an issue except 152 // when there are mistakes in this assembly code that could generate 153 // a spurious fault. Ask me how I know... 154 155 const Register method = rbx; 156 Label throw_icce; 157 158 // Get methodOop and entrypoint for compiler 159 __ lookup_interface_method(// inputs: rec. class, interface, itable index 160 r10, rax, itable_index, 161 // outputs: method, scan temp. reg 162 method, r11, 163 throw_icce); 164 165 // method (rbx): methodOop 166 // j_rarg0: receiver 167 168 #ifdef ASSERT 169 if (DebugVtables) { 170 Label L2; 171 __ cmpptr(method, (int32_t)NULL_WORD); 172 __ jcc(Assembler::equal, L2); 173 __ cmpptr(Address(method, methodOopDesc::from_compiled_offset()), (int32_t)NULL_WORD); 174 __ jcc(Assembler::notZero, L2); 175 __ stop("compiler entrypoint is null"); 176 __ bind(L2); 177 } 178 #endif // ASSERT 179 180 // rbx: methodOop 181 // j_rarg0: receiver 182 address ame_addr = __ pc(); 183 __ jmp(Address(method, methodOopDesc::from_compiled_offset())); 184 185 __ bind(throw_icce); 186 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry())); 187 188 __ flush(); 189 190 if (PrintMiscellaneous && (WizardMode || Verbose)) { 191 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d", 192 itable_index, s->entry_point(), 193 (int)(s->code_end() - s->entry_point()), 194 (int)(s->code_end() - __ pc())); 195 } 196 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 197 // shut the door on sizing bugs 198 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 199 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 200 201 s->set_exception_points(npe_addr, ame_addr); 202 return s; 203 } 204 205 int VtableStub::pd_code_size_limit(bool is_vtable_stub) { 206 if (is_vtable_stub) { 207 // Vtable stub size 208 return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) + 209 (UseCompressedOops ? 16 : 0); // 1 leaq can be 3 bytes + 1 long 210 } else { 211 // Itable stub size 212 return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) + 213 (UseCompressedOops ? 32 : 0); // 2 leaqs 214 } 215 // In order to tune these parameters, run the JVM with VM options 216 // +PrintMiscellaneous and +WizardMode to see information about 217 // actual itable stubs. Look for lines like this: 218 // itable #1 at 0x5551212[71] left over: 3 219 // Reduce the constants so that the "left over" number is >=3 220 // for the common cases. 221 // Do not aim at a left-over number of zero, because a 222 // large vtable or itable index (>= 32) will require a 32-bit 223 // immediate displacement instead of an 8-bit one. 224 // 225 // The JVM98 app. _202_jess has a megamorphic interface call. 226 // The itable code looks like this: 227 // Decoding VtableStub itbl[1]@12 228 // mov 0x8(%rsi),%r10 229 // mov 0x198(%r10),%r11d 230 // lea 0x218(%r10,%r11,8),%r11 231 // lea 0x8(%r10),%r10 232 // mov (%r11),%rbx 233 // cmp %rbx,%rax 234 // je success 235 // loop: 236 // test %rbx,%rbx 237 // je throw_icce 238 // add $0x10,%r11 239 // mov (%r11),%rbx 240 // cmp %rbx,%rax 241 // jne loop 242 // success: 243 // mov 0x8(%r11),%r11d 244 // mov (%r10,%r11,1),%rbx 245 // jmpq *0x60(%rbx) 246 // throw_icce: 247 // jmpq throw_ICCE_entry 248 } 249 250 int VtableStub::pd_code_alignment() { 251 return wordSize; 252 }