1 /* 2 * Copyright (c) 2003, 2014, 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 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC 39 40 // machine-dependent part of VtableStubs: create VtableStub of correct size and 41 // initialize its code 42 43 #define __ masm-> 44 45 #ifndef PRODUCT 46 extern "C" void bad_compiled_vtable_index(JavaThread* thread, 47 oop receiver, 48 int index); 49 #endif 50 51 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) { 52 const int amd64_code_length = VtableStub::pd_code_size_limit(true); 53 VtableStub* s = new(amd64_code_length) VtableStub(true, vtable_index); 54 // Can be NULL if there is no free space in the code cache. 55 if (s == NULL) { 56 return NULL; 57 } 58 59 ResourceMark rm; 60 CodeBuffer cb(s->entry_point(), amd64_code_length); 61 MacroAssembler* masm = new MacroAssembler(&cb); 62 63 #ifndef PRODUCT 64 if (CountCompiledCalls) { 65 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 66 } 67 #endif 68 69 // get receiver (need to skip return address on top of stack) 70 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 71 72 // Free registers (non-args) are rax, rbx 73 74 // get receiver klass 75 address npe_addr = __ pc(); 76 __ load_klass(rax, j_rarg0); 77 78 #ifndef PRODUCT 79 if (DebugVtables) { 80 Label L; 81 // check offset vs vtable length 82 __ cmpl(Address(rax, InstanceKlass::vtable_length_offset() * wordSize), 83 vtable_index * vtableEntry::size()); 84 __ jcc(Assembler::greater, L); 85 __ movl(rbx, vtable_index); 86 __ call_VM(noreg, 87 CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx); 88 __ bind(L); 89 } 90 #endif // PRODUCT 91 92 // load Method* and target address 93 const Register method = rbx; 94 95 __ lookup_virtual_method(rax, vtable_index, method); 96 97 if (DebugVtables) { 98 Label L; 99 __ cmpptr(method, (int32_t)NULL_WORD); 100 __ jcc(Assembler::equal, L); 101 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 102 __ jcc(Assembler::notZero, L); 103 __ stop("Vtable entry is NULL"); 104 __ bind(L); 105 } 106 // rax: receiver klass 107 // rbx: Method* 108 // rcx: receiver 109 address ame_addr = __ pc(); 110 __ jmp( Address(rbx, Method::from_compiled_offset())); 111 112 __ flush(); 113 114 if (PrintMiscellaneous && (WizardMode || Verbose)) { 115 tty->print_cr("vtable #%d at " PTR_FORMAT "[%d] left over: %d", 116 vtable_index, s->entry_point(), 117 (int)(s->code_end() - s->entry_point()), 118 (int)(s->code_end() - __ pc())); 119 } 120 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 121 // shut the door on sizing bugs 122 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 123 assert(vtable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 124 125 s->set_exception_points(npe_addr, ame_addr); 126 return s; 127 } 128 129 130 VtableStub* VtableStubs::create_itable_stub(int itable_index) { 131 // Note well: pd_code_size_limit is the absolute minimum we can get 132 // away with. If you add code here, bump the code stub size 133 // returned by pd_code_size_limit! 134 const int amd64_code_length = VtableStub::pd_code_size_limit(false); 135 VtableStub* s = new(amd64_code_length) VtableStub(false, itable_index); 136 // Can be NULL if there is no free space in the code cache. 137 if (s == NULL) { 138 return NULL; 139 } 140 141 ResourceMark rm; 142 CodeBuffer cb(s->entry_point(), amd64_code_length); 143 MacroAssembler* masm = new MacroAssembler(&cb); 144 145 #ifndef PRODUCT 146 if (CountCompiledCalls) { 147 __ incrementl(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 148 } 149 #endif 150 151 // Entry arguments: 152 // rax: Interface 153 // j_rarg0: Receiver 154 155 // Free registers (non-args) are rax (interface), rbx 156 157 // get receiver (need to skip return address on top of stack) 158 159 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 160 // get receiver klass (also an implicit null-check) 161 address npe_addr = __ pc(); 162 163 // Most registers are in use; we'll use rax, rbx, r10, r11 164 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them) 165 __ load_klass(r10, j_rarg0); 166 167 // If we take a trap while this arg is on the stack we will not 168 // be able to walk the stack properly. This is not an issue except 169 // when there are mistakes in this assembly code that could generate 170 // a spurious fault. Ask me how I know... 171 172 const Register method = rbx; 173 Label throw_icce; 174 175 // Get Method* and entrypoint for compiler 176 __ lookup_interface_method(// inputs: rec. class, interface, itable index 177 r10, rax, itable_index, 178 // outputs: method, scan temp. reg 179 method, r11, 180 throw_icce); 181 182 // method (rbx): Method* 183 // j_rarg0: receiver 184 185 #ifdef ASSERT 186 if (DebugVtables) { 187 Label L2; 188 __ cmpptr(method, (int32_t)NULL_WORD); 189 __ jcc(Assembler::equal, L2); 190 __ cmpptr(Address(method, Method::from_compiled_offset()), (int32_t)NULL_WORD); 191 __ jcc(Assembler::notZero, L2); 192 __ stop("compiler entrypoint is null"); 193 __ bind(L2); 194 } 195 #endif // ASSERT 196 197 // rbx: Method* 198 // j_rarg0: receiver 199 address ame_addr = __ pc(); 200 __ jmp(Address(method, Method::from_compiled_offset())); 201 202 __ bind(throw_icce); 203 __ jump(RuntimeAddress(StubRoutines::throw_IncompatibleClassChangeError_entry())); 204 205 __ flush(); 206 207 if (PrintMiscellaneous && (WizardMode || Verbose)) { 208 tty->print_cr("itable #%d at " PTR_FORMAT "[%d] left over: %d", 209 itable_index, s->entry_point(), 210 (int)(s->code_end() - s->entry_point()), 211 (int)(s->code_end() - __ pc())); 212 } 213 guarantee(__ pc() <= s->code_end(), "overflowed buffer"); 214 // shut the door on sizing bugs 215 int slop = 3; // 32-bit offset is this much larger than an 8-bit one 216 assert(itable_index > 10 || __ pc() + slop <= s->code_end(), "room for 32-bit offset"); 217 218 s->set_exception_points(npe_addr, ame_addr); 219 return s; 220 } 221 222 int VtableStub::pd_code_size_limit(bool is_vtable_stub) { 223 if (is_vtable_stub) { 224 // Vtable stub size 225 return (DebugVtables ? 512 : 24) + (CountCompiledCalls ? 13 : 0) + 226 (UseCompressedClassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0); 227 } else { 228 // Itable stub size 229 return (DebugVtables ? 512 : 74) + (CountCompiledCalls ? 13 : 0) + 230 (UseCompressedClassPointers ? MacroAssembler::instr_size_for_decode_klass_not_null() : 0); 231 } 232 // In order to tune these parameters, run the JVM with VM options 233 // +PrintMiscellaneous and +WizardMode to see information about 234 // actual itable stubs. Look for lines like this: 235 // itable #1 at 0x5551212[71] left over: 3 236 // Reduce the constants so that the "left over" number is >=3 237 // for the common cases. 238 // Do not aim at a left-over number of zero, because a 239 // large vtable or itable index (>= 32) will require a 32-bit 240 // immediate displacement instead of an 8-bit one. 241 // 242 // The JVM98 app. _202_jess has a megamorphic interface call. 243 // The itable code looks like this: 244 // Decoding VtableStub itbl[1]@12 245 // mov 0x8(%rsi),%r10 246 // mov 0x198(%r10),%r11d 247 // lea 0x218(%r10,%r11,8),%r11 248 // lea 0x8(%r10),%r10 249 // mov (%r11),%rbx 250 // cmp %rbx,%rax 251 // je success 252 // loop: 253 // test %rbx,%rbx 254 // je throw_icce 255 // add $0x10,%r11 256 // mov (%r11),%rbx 257 // cmp %rbx,%rax 258 // jne loop 259 // success: 260 // mov 0x8(%r11),%r11d 261 // mov (%r10,%r11,1),%rbx 262 // jmpq *0x60(%rbx) 263 // throw_icce: 264 // jmpq throw_ICCE_entry 265 } 266 267 int VtableStub::pd_code_alignment() { 268 return wordSize; 269 }