1 /* 2 * Copyright (c) 2003, 2013, 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, 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 // Can be NULL if there is no free space in the code cache. 53 if (s == NULL) { 54 return NULL; 55 } 56 57 ResourceMark rm; 58 CodeBuffer cb(s->entry_point(), amd64_code_length); 59 MacroAssembler* masm = new MacroAssembler(&cb); 60 61 #ifndef PRODUCT 62 if (CountCompiledCalls) { 63 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 64 } 65 #endif 66 67 // get receiver (need to skip return address on top of stack) 68 assert(VtableStub::receiver_location() == j_rarg0.as_VMReg(), "receiver expected in j_rarg0"); 69 70 // Free registers (non-args) are rax, rbx 71 72 // get receiver klass 73 address npe_addr = __ pc(); 74 __ load_klass(rax, j_rarg0); 75 76 #ifndef PRODUCT 77 if (DebugVtables) { 78 Label L; 79 // check offset vs vtable length 80 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset() * wordSize), 81 vtable_index * vtableEntry::size()); 82 __ jcc(Assembler::greater, L); 83 __ movl(rbx, vtable_index); 84 __ call_VM(noreg, 85 CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx); 86 __ bind(L); 87 } 88 #endif // PRODUCT 89 90 // load Method* and target address 91 const Register method = rbx; 92 93 __ lookup_virtual_method(rax, vtable_index, method); 94 95 if (DebugVtables) { 96 Label L; 97 __ cmpptr(method, (int32_t)NULL_WORD); 98 __ jcc(Assembler::equal, L); 99 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 100 __ jcc(Assembler::notZero, L); 101 __ stop("Vtable entry is NULL"); 102 __ bind(L); 103 } 104 // rax: receiver klass 105 // rbx: Method* 106 // rcx: receiver 107 address ame_addr = __ pc(); 108 __ jmp( Address(rbx, Method::from_compiled_offset())); 109 110 __ flush(); 111 112 if (PrintMiscellaneous && (WizardMode || Verbose)) { 113 tty->print_cr("vtable #%d at "PTR_FORMAT"[%d] left over: %d", 114 vtable_index, s->entry_point(), 115 (int)(s->code_end() - s->entry_point()), 116 (int)(s->code_end() - __ pc())); 117 } 118 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 119 // shut the door on sizing bugs 120 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 121 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 122 123 s->set_exception_points(npe_addr, ame_addr); 124 return s; 125 } 126 127 128 VtableStub* VtableStubs::create_itable_stub(int itable_index) { 129 // Note well: pd_code_size_limit is the absolute minimum we can get 130 // away with. If you add code here, bump the code stub size 131 // returned by pd_code_size_limit! 132 const int amd64_code_length = VtableStub::pd_code_size_limit(false); 133 VtableStub* s = new(amd64_code_length) VtableStub(false, itable_index); 134 // Can be NULL if there is no free space in the code cache. 135 if (s == NULL) { 136 return NULL; 137 } 138 139 ResourceMark rm; 140 CodeBuffer cb(s->entry_point(), amd64_code_length); 141 MacroAssembler* masm = new MacroAssembler(&cb); 142 143 #ifndef PRODUCT 144 if (CountCompiledCalls) { 145 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 146 } 147 #endif 148 149 // Entry arguments: 150 // rax: Interface 151 // j_rarg0: Receiver 152 153 // Free registers (non-args) are rax (interface), rbx 154 155 // get receiver (need to skip return address on top of stack) 156 157 assert(VtableStub::receiver_location() == j_rarg0.as_VMReg(), "receiver expected in j_rarg0"); 158 // get receiver klass (also an implicit null-check) 159 address npe_addr = __ pc(); 160 161 // Most registers are in use; we'll use rax, rbx, r10, r11 162 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them) 163 __ load_klass(r10, j_rarg0); 164 165 // If we take a trap while this arg is on the stack we will not 166 // be able to walk the stack properly. This is not an issue except 167 // when there are mistakes in this assembly code that could generate 168 // a spurious fault. Ask me how I know... 169 170 const Register method = rbx; 171 Label throw_icce; 172 173 // Get Method* and entrypoint for compiler 174 __ lookup_interface_method(// inputs: rec. class, interface, itable index 175 r10, rax, itable_index, 176 // outputs: method, scan temp. reg 177 method, r11, 178 throw_icce); 179 180 // method (rbx): Method* 181 // j_rarg0: receiver 182 183 #ifdef ASSERT 184 if (DebugVtables) { 185 Label L2; 186 __ cmpptr(method, (int32_t)NULL_WORD); 187 __ jcc(Assembler::equal, L2); 188 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 189 __ jcc(Assembler::notZero, L2); 190 __ stop("compiler entrypoint is null"); 191 __ bind(L2); 192 } 193 #endif // ASSERT 194 195 // rbx: Method* 196 // j_rarg0: receiver 197 address ame_addr = __ pc(); 198 __ jmp(Address(method, Method::from_compiled_offset())); 199 200 __ bind(throw_icce); 201 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry())); 202 203 __ flush(); 204 205 if (PrintMiscellaneous && (WizardMode || Verbose)) { 206 tty->print_cr("itable #%d at "PTR_FORMAT"[%d] left over: %d", 207 itable_index, s->entry_point(), 208 (int)(s->code_end() - s->entry_point()), 209 (int)(s->code_end() - __ pc())); 210 } 211 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 212 // shut the door on sizing bugs 213 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 214 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 215 216 s->set_exception_points(npe_addr, ame_addr); 217 return s; 218 } 219 220 int VtableStub::pd_code_size_limit(bool is_vtable_stub) { 221 if (is_vtable_stub) { 222 // Vtable stub size 223 return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) + 224 (UseCompressedClassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0); 225 } else { 226 // Itable stub size 227 return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) + 228 (UseCompressedClassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0); 229 } 230 // In order to tune these parameters, run the JVM with VM options 231 // +PrintMiscellaneous and +WizardMode to see information about 232 // actual itable stubs. Look for lines like this: 233 // itable #1 at 0x5551212[71] left over: 3 234 // Reduce the constants so that the "left over" number is >=3 235 // for the common cases. 236 // Do not aim at a left-over number of zero, because a 237 // large vtable or itable index (>= 32) will require a 32-bit 238 // immediate displacement instead of an 8-bit one. 239 // 240 // The JVM98 app. _202_jess has a megamorphic interface call. 241 // The itable code looks like this: 242 // Decoding VtableStub itbl[1]@12 243 // mov 0x8(%rsi),%r10 244 // mov 0x198(%r10),%r11d 245 // lea 0x218(%r10,%r11,8),%r11 246 // lea 0x8(%r10),%r10 247 // mov (%r11),%rbx 248 // cmp %rbx,%rax 249 // je success 250 // loop: 251 // test %rbx,%rbx 252 // je throw_icce 253 // add $0x10,%r11 254 // mov (%r11),%rbx 255 // cmp %rbx,%rax 256 // jne loop 257 // success: 258 // mov 0x8(%r11),%r11d 259 // mov (%r10,%r11,1),%rbx 260 // jmpq *0x60(%rbx) 261 // throw_icce: 262 // jmpq throw_ICCE_entry 263 } 264 265 int VtableStub::pd_code_alignment() { 266 return wordSize; 267 }