1 /* 2 * Copyright (c) 2003, 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_64.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, 45 oop receiver, 46 int index); 47 #endif 48 49 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) { 50 const int amd64_code_length = VtableStub::pd_code_size_limit(true); 51 VtableStub* s = new(amd64_code_length) VtableStub(true, vtable_index); 52 ResourceMark rm; 53 CodeBuffer cb(s->entry_point(), amd64_code_length); 54 MacroAssembler* masm = new MacroAssembler(&cb); 55 56 #ifndef PRODUCT 57 if (CountCompiledCalls) { 58 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 59 } 60 #endif 61 62 // get receiver (need to skip return address on top of stack) 63 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 64 65 // Free registers (non-args) are rax, rbx 66 67 // get receiver klass 68 address npe_addr = __ pc(); 69 __ load_klass(rax, j_rarg0); 70 71 #ifndef PRODUCT 72 if (DebugVtables) { 73 Label L; 74 // check offset vs vtable length 75 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset() * wordSize), 76 vtable_index * vtableEntry::size()); 77 __ jcc(Assembler::greater, L); 78 __ movl(rbx, vtable_index); 79 __ call_VM(noreg, 80 CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx); 81 __ bind(L); 82 } 83 #endif // PRODUCT 84 85 // load Method* and target address 86 const Register method = rbx; 87 88 __ lookup_virtual_method(rax, vtable_index, method); 89 90 if (DebugVtables) { 91 Label L; 92 __ cmpptr(method, (int32_t)NULL_WORD); 93 __ jcc(Assembler::equal, L); 94 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 95 __ jcc(Assembler::notZero, L); 96 __ stop("Vtable entry is NULL"); 97 __ bind(L); 98 } 99 // rax: receiver klass 100 // rbx: Method* 101 // rcx: receiver 102 address ame_addr = __ pc(); 103 __ jmp( Address(rbx, Method::from_compiled_offset())); 104 105 __ flush(); 106 107 if (PrintMiscellaneous && (WizardMode || Verbose)) { 108 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d", 109 vtable_index, s->entry_point(), 110 (int)(s->code_end() - s->entry_point()), 111 (int)(s->code_end() - __ pc())); 112 } 113 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 114 // shut the door on sizing bugs 115 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 116 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 117 118 s->set_exception_points(npe_addr, ame_addr); 119 return s; 120 } 121 122 123 VtableStub* VtableStubs::create_itable_stub(int itable_index) { 124 // Note well: pd_code_size_limit is the absolute minimum we can get 125 // away with. If you add code here, bump the code stub size 126 // returned by pd_code_size_limit! 127 const int amd64_code_length = VtableStub::pd_code_size_limit(false); 128 VtableStub* s = new(amd64_code_length) VtableStub(false, itable_index); 129 ResourceMark rm; 130 CodeBuffer cb(s->entry_point(), amd64_code_length); 131 MacroAssembler* masm = new MacroAssembler(&cb); 132 133 #ifndef PRODUCT 134 if (CountCompiledCalls) { 135 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 136 } 137 #endif 138 139 // Entry arguments: 140 // rax: Interface 141 // j_rarg0: Receiver 142 143 // Free registers (non-args) are rax (interface), rbx 144 145 // get receiver (need to skip return address on top of stack) 146 147 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 148 // get receiver klass (also an implicit null-check) 149 address npe_addr = __ pc(); 150 151 // Most registers are in use; we'll use rax, rbx, r10, r11 152 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them) 153 __ load_klass(r10, j_rarg0); 154 155 // If we take a trap while this arg is on the stack we will not 156 // be able to walk the stack properly. This is not an issue except 157 // when there are mistakes in this assembly code that could generate 158 // a spurious fault. Ask me how I know... 159 160 const Register method = rbx; 161 Label throw_icce; 162 163 // Get Method* and entrypoint for compiler 164 __ lookup_interface_method(// inputs: rec. class, interface, itable index 165 r10, rax, itable_index, 166 // outputs: method, scan temp. reg 167 method, r11, 168 throw_icce); 169 170 // method (rbx): Method* 171 // j_rarg0: receiver 172 173 #ifdef ASSERT 174 if (DebugVtables) { 175 Label L2; 176 __ cmpptr(method, (int32_t)NULL_WORD); 177 __ jcc(Assembler::equal, L2); 178 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 179 __ jcc(Assembler::notZero, L2); 180 __ stop("compiler entrypoint is null"); 181 __ bind(L2); 182 } 183 #endif // ASSERT 184 185 // rbx: Method* 186 // j_rarg0: receiver 187 address ame_addr = __ pc(); 188 __ jmp(Address(method, Method::from_compiled_offset())); 189 190 __ bind(throw_icce); 191 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry())); 192 193 __ flush(); 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 239 // je success 240 // loop: 241 // test %rbx,%rbx 242 // je throw_icce 243 // add $0x10,%r11 244 // mov (%r11),%rbx 245 // cmp %rbx,%rax 246 // jne loop 247 // success: 248 // mov 0x8(%r11),%r11d 249 // mov (%r10,%r11,1),%rbx 250 // jmpq *0x60(%rbx) 251 // throw_icce: 252 // jmpq throw_ICCE_entry 253 } 254 255 int VtableStub::pd_code_alignment() { 256 return wordSize; 257 }