1 /* 2 * Copyright (c) 1997, 2012, 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 "asm/macroAssembler.hpp" 27 #include "code/vtableStubs.hpp" 28 #include "interp_masm_x86.hpp" 29 #include "memory/resourceArea.hpp" 30 #include "oops/instanceKlass.hpp" 31 #include "oops/klassVtable.hpp" 32 #include "runtime/sharedRuntime.hpp" 33 #include "vmreg_x86.inline.hpp" 34 #ifdef COMPILER2 35 #include "opto/runtime.hpp" 36 #endif 37 38 // machine-dependent part of VtableStubs: create VtableStub of correct size and 39 // initialize its code 40 41 #define __ masm-> 42 43 #ifndef PRODUCT 44 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index); 45 #endif 46 47 // These stubs are used by the compiler only. 48 // Argument registers, which must be preserved: 49 // rcx - receiver (always first argument) 50 // rdx - second argument (if any) 51 // Other registers that might be usable: 52 // rax - inline cache register (is interface for itable stub) 53 // rbx - method (used when calling out to interpreter) 54 // Available now, but may become callee-save at some point: 55 // rsi, rdi 56 // Note that rax and rdx are also used for return values. 57 // 58 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) { 59 const int i486_code_length = VtableStub::pd_code_size_limit(true); 60 VtableStub* s = new(i486_code_length) VtableStub(true, vtable_index); 61 // Can be NULL if there is no free space in the code cache. 62 if (s == NULL) { 63 return NULL; 64 } 65 66 ResourceMark rm; 67 CodeBuffer cb(s->entry_point(), i486_code_length); 68 MacroAssembler* masm = new MacroAssembler(&cb); 69 70 #ifndef PRODUCT 71 72 if (CountCompiledCalls) { 73 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 74 } 75 #endif /* PRODUCT */ 76 77 // get receiver (need to skip return address on top of stack) 78 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx"); 79 80 // get receiver klass 81 address npe_addr = __ pc(); 82 __ movptr(rax, Address(rcx, oopDesc::klass_offset_in_bytes())); 83 84 #ifndef PRODUCT 85 if (DebugVtables) { 86 Label L; 87 // check offset vs vtable length 88 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset()*wordSize), vtable_index*vtableEntry::size()); 89 __ jcc(Assembler::greater, L); 90 __ movl(rbx, vtable_index); 91 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), rcx, rbx); 92 __ bind(L); 93 } 94 #endif // PRODUCT 95 96 const Register method = rbx; 97 98 // load Method* and target address 99 __ lookup_virtual_method(rax, vtable_index, method); 100 101 if (DebugVtables) { 102 Label L; 103 __ cmpptr(method, (int32_t)NULL_WORD); 104 __ jcc(Assembler::equal, L); 105 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 106 __ jcc(Assembler::notZero, L); 107 __ stop("Vtable entry is NULL"); 108 __ bind(L); 109 } 110 111 // rax,: receiver klass 112 // method (rbx): Method* 113 // rcx: receiver 114 address ame_addr = __ pc(); 115 __ jmp( Address(method, Method::from_compiled_offset())); 116 117 masm->flush(); 118 119 if (PrintMiscellaneous && (WizardMode || Verbose)) { 120 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d", 121 vtable_index, s->entry_point(), 122 (int)(s->code_end() - s->entry_point()), 123 (int)(s->code_end() - __ pc())); 124 } 125 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 126 // shut the door on sizing bugs 127 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 128 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 129 130 s->set_exception_points(npe_addr, ame_addr); 131 return s; 132 } 133 134 135 VtableStub* VtableStubs::create_itable_stub(int itable_index) { 136 // Note well: pd_code_size_limit is the absolute minimum we can get away with. If you 137 // add code here, bump the code stub size returned by pd_code_size_limit! 138 const int i486_code_length = VtableStub::pd_code_size_limit(false); 139 VtableStub* s = new(i486_code_length) VtableStub(false, itable_index); 140 // Can be NULL if there is no free space in the code cache. 141 if (s == NULL) { 142 return NULL; 143 } 144 145 ResourceMark rm; 146 CodeBuffer cb(s->entry_point(), i486_code_length); 147 MacroAssembler* masm = new MacroAssembler(&cb); 148 149 // Entry arguments: 150 // rax,: Interface 151 // rcx: Receiver 152 153 #ifndef PRODUCT 154 if (CountCompiledCalls) { 155 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 156 } 157 #endif /* PRODUCT */ 158 // get receiver (need to skip return address on top of stack) 159 160 assert(VtableStub::receiver_location() == rcx->as_VMReg(), "receiver expected in rcx"); 161 162 // get receiver klass (also an implicit null-check) 163 address npe_addr = __ pc(); 164 __ movptr(rsi, Address(rcx, oopDesc::klass_offset_in_bytes())); 165 166 // Most registers are in use; we'll use rax, rbx, rsi, rdi 167 // (If we need to make rsi, rdi callee-save, do a push/pop here.) 168 const Register method = rbx; 169 Label throw_icce; 170 171 // Get Method* and entrypoint for compiler 172 __ lookup_interface_method(// inputs: rec. class, interface, itable index 173 rsi, rax, itable_index, 174 // outputs: method, scan temp. reg 175 method, rdi, 176 throw_icce); 177 178 // method (rbx): Method* 179 // rcx: receiver 180 181 #ifdef ASSERT 182 if (DebugVtables) { 183 Label L1; 184 __ cmpptr(method, (int32_t)NULL_WORD); 185 __ jcc(Assembler::equal, L1); 186 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 187 __ jcc(Assembler::notZero, L1); 188 __ stop("Method* is null"); 189 __ bind(L1); 190 } 191 #endif // ASSERT 192 193 address ame_addr = __ pc(); 194 __ jmp(Address(method, Method::from_compiled_offset())); 195 196 __ bind(throw_icce); 197 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry())); 198 masm->flush(); 199 200 if (PrintMiscellaneous && (WizardMode || Verbose)) { 201 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d", 202 itable_index, s->entry_point(), 203 (int)(s->code_end() - s->entry_point()), 204 (int)(s->code_end() - __ pc())); 205 } 206 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 207 // shut the door on sizing bugs 208 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 209 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 210 211 s->set_exception_points(npe_addr, ame_addr); 212 return s; 213 } 214 215 216 217 int VtableStub::pd_code_size_limit(bool is_vtable_stub) { 218 if (is_vtable_stub) { 219 // Vtable stub size 220 return (DebugVtables ? 210 : 16) + (CountCompiledCalls ? 6 : 0); 221 } else { 222 // Itable stub size 223 return (DebugVtables ? 256 : 66) + (CountCompiledCalls ? 6 : 0); 224 } 225 // In order to tune these parameters, run the JVM with VM options 226 // +PrintMiscellaneous and +WizardMode to see information about 227 // actual itable stubs. Look for lines like this: 228 // itable #1 at 0x5551212[65] left over: 3 229 // Reduce the constants so that the "left over" number is >=3 230 // for the common cases. 231 // Do not aim at a left-over number of zero, because a 232 // large vtable or itable index (> 16) will require a 32-bit 233 // immediate displacement instead of an 8-bit one. 234 // 235 // The JVM98 app. _202_jess has a megamorphic interface call. 236 // The itable code looks like this: 237 // Decoding VtableStub itbl[1]@1 238 // mov 0x4(%ecx),%esi 239 // mov 0xe8(%esi),%edi 240 // lea 0x130(%esi,%edi,4),%edi 241 // add $0x7,%edi 242 // and $0xfffffff8,%edi 243 // lea 0x4(%esi),%esi 244 // mov (%edi),%ebx 245 // cmp %ebx,%eax 246 // je success 247 // loop: 248 // test %ebx,%ebx 249 // je throw_icce 250 // add $0x8,%edi 251 // mov (%edi),%ebx 252 // cmp %ebx,%eax 253 // jne loop 254 // success: 255 // mov 0x4(%edi),%edi 256 // mov (%esi,%edi,1),%ebx 257 // jmp *0x44(%ebx) 258 // throw_icce: 259 // jmp throw_ICCE_entry 260 } 261 262 int VtableStub::pd_code_alignment() { 263 return wordSize; 264 }