1 /* 2 * Copyright (c) 2003, 2021, 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/compiledICHolder.hpp" 31 #include "oops/instanceKlass.hpp" 32 #include "oops/klassVtable.hpp" 33 #include "runtime/sharedRuntime.hpp" 34 #include "vmreg_x86.inline.hpp" 35 #ifdef COMPILER2 36 #include "opto/runtime.hpp" 37 #endif 38 39 // machine-dependent part of VtableStubs: create VtableStub of correct size and 40 // initialize its code 41 42 #define __ masm-> 43 44 #ifndef PRODUCT 45 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index); 46 #endif 47 48 VtableStub* VtableStubs::create_vtable_stub(int vtable_index, bool caller_is_c1) { 49 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing. 50 const int stub_code_length = code_size_limit(true); 51 Register tmp_load_klass = rscratch1; 52 VtableStub* s = new(stub_code_length) VtableStub(true, vtable_index, caller_is_c1); 53 // Can be NULL if there is no free space in the code cache. 54 if (s == NULL) { 55 return NULL; 56 } 57 58 // Count unused bytes in instruction sequences of variable size. 59 // We add them to the computed buffer size in order to avoid 60 // overflow in subsequently generated stubs. 61 address start_pc; 62 int slop_bytes = 0; 63 int slop_delta = 0; 64 // No variance was detected in vtable stub sizes. Setting index_dependent_slop == 0 will unveil any deviation from this observation. 65 const int index_dependent_slop = 0; 66 ByteSize entry_offset = caller_is_c1 ? Method::from_compiled_inline_offset() : Method::from_compiled_inline_ro_offset(); 67 68 ResourceMark rm; 69 CodeBuffer cb(s->entry_point(), stub_code_length); 70 MacroAssembler* masm = new MacroAssembler(&cb); 71 72 #if (!defined(PRODUCT) && defined(COMPILER2)) 73 if (CountCompiledCalls) { 74 __ incrementq(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 75 } 76 #endif 77 78 // get receiver (need to skip return address on top of stack) 79 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 80 81 // Free registers (non-args) are rax, rbx 82 83 // get receiver klass 84 address npe_addr = __ pc(); 85 __ load_klass(rax, j_rarg0, tmp_load_klass); 86 87 #ifndef PRODUCT 88 if (DebugVtables) { 89 Label L; 90 start_pc = __ pc(); 91 // check offset vs vtable length 92 __ cmpl(Address(rax, Klass::vtable_length_offset()), vtable_index*vtableEntry::size()); 93 slop_delta = 12 - (__ pc() - start_pc); // cmpl varies in length, depending on data 94 slop_bytes += slop_delta; 95 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta); 96 97 __ jcc(Assembler::greater, L); 98 __ movl(rbx, vtable_index); 99 // VTABLE TODO: find upper bound for call_VM length. 100 start_pc = __ pc(); 101 __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, rbx); 102 slop_delta = 550 - (__ pc() - start_pc); 103 slop_bytes += slop_delta; 104 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta); 105 __ bind(L); 106 } 107 #endif // PRODUCT 108 109 const Register method = rbx; 110 111 // load Method* and target address 112 start_pc = __ pc(); 113 __ lookup_virtual_method(rax, vtable_index, method); 114 slop_delta = 8 - (int)(__ pc() - start_pc); 115 slop_bytes += slop_delta; 116 assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta); 117 118 #ifndef PRODUCT 119 if (DebugVtables) { 120 Label L; 121 __ cmpptr(method, (int32_t)NULL_WORD); 122 __ jcc(Assembler::equal, L); 123 __ cmpptr(Address(method, entry_offset), (int32_t)NULL_WORD); 124 __ jcc(Assembler::notZero, L); 125 __ stop("Vtable entry is NULL"); 126 __ bind(L); 127 } 128 #endif // PRODUCT 129 130 // rax: receiver klass 131 // method (rbx): Method* 132 // rcx: receiver 133 address ame_addr = __ pc(); 134 __ jmp( Address(rbx, entry_offset)); 135 136 masm->flush(); 137 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets 138 bookkeeping(masm, tty, s, npe_addr, ame_addr, true, vtable_index, slop_bytes, index_dependent_slop); 139 140 return s; 141 } 142 143 144 VtableStub* VtableStubs::create_itable_stub(int itable_index, bool caller_is_c1) { 145 // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing. 146 const int stub_code_length = code_size_limit(false); 147 ByteSize entry_offset = caller_is_c1 ? Method::from_compiled_inline_offset() : Method::from_compiled_inline_ro_offset(); 148 VtableStub* s = new(stub_code_length) VtableStub(false, itable_index, caller_is_c1); 149 // Can be NULL if there is no free space in the code cache. 150 if (s == NULL) { 151 return NULL; 152 } 153 154 // Count unused bytes in instruction sequences of variable size. 155 // We add them to the computed buffer size in order to avoid 156 // overflow in subsequently generated stubs. 157 address start_pc; 158 int slop_bytes = 0; 159 int slop_delta = 0; 160 const int index_dependent_slop = (itable_index == 0) ? 4 : // code size change with transition from 8-bit to 32-bit constant (@index == 16). 161 (itable_index < 16) ? 3 : 0; // index == 0 generates even shorter code. 162 163 ResourceMark rm; 164 CodeBuffer cb(s->entry_point(), stub_code_length); 165 MacroAssembler *masm = new MacroAssembler(&cb); 166 167 #if (!defined(PRODUCT) && defined(COMPILER2)) 168 if (CountCompiledCalls) { 169 __ incrementq(ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr())); 170 } 171 #endif // PRODUCT 172 173 // Entry arguments: 174 // rax: CompiledICHolder 175 // j_rarg0: Receiver 176 177 // Most registers are in use; we'll use rax, rbx, r10, r11 178 // (various calling sequences use r[cd]x, r[sd]i, r[89]; stay away from them) 179 const Register recv_klass_reg = r10; 180 const Register holder_klass_reg = rax; // declaring interface klass (DECC) 181 const Register resolved_klass_reg = rbx; // resolved interface klass (REFC) 182 const Register temp_reg = r11; 183 184 const Register icholder_reg = rax; 185 __ movptr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset())); 186 __ movptr(holder_klass_reg, Address(icholder_reg, CompiledICHolder::holder_metadata_offset())); 187 188 Label L_no_such_interface; 189 190 // get receiver klass (also an implicit null-check) 191 assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0"); 192 address npe_addr = __ pc(); 193 __ load_klass(recv_klass_reg, j_rarg0, temp_reg); 194 195 start_pc = __ pc(); 196 197 // Receiver subtype check against REFC. 198 // Destroys recv_klass_reg value. 199 __ lookup_interface_method(// inputs: rec. class, interface 200 recv_klass_reg, resolved_klass_reg, noreg, 201 // outputs: scan temp. reg1, scan temp. reg2 202 recv_klass_reg, temp_reg, 203 L_no_such_interface, 204 /*return_method=*/false); 205 206 const ptrdiff_t typecheckSize = __ pc() - start_pc; 207 start_pc = __ pc(); 208 209 // Get selected method from declaring class and itable index 210 const Register method = rbx; 211 __ load_klass(recv_klass_reg, j_rarg0, temp_reg); // restore recv_klass_reg 212 __ lookup_interface_method(// inputs: rec. class, interface, itable index 213 recv_klass_reg, holder_klass_reg, itable_index, 214 // outputs: method, scan temp. reg 215 method, temp_reg, 216 L_no_such_interface); 217 218 const ptrdiff_t lookupSize = __ pc() - start_pc; 219 220 // We expect we need index_dependent_slop extra bytes. Reason: 221 // The emitted code in lookup_interface_method changes when itable_index exceeds 15. 222 // For linux, a very narrow estimate would be 112, but Solaris requires some more space (130). 223 const ptrdiff_t estimate = 144; 224 const ptrdiff_t codesize = typecheckSize + lookupSize + index_dependent_slop; 225 slop_delta = (int)(estimate - codesize); 226 slop_bytes += slop_delta; 227 assert(slop_delta >= 0, "itable #%d: Code size estimate (%d) for lookup_interface_method too small, required: %d", itable_index, (int)estimate, (int)codesize); 228 229 // If we take a trap while this arg is on the stack we will not 230 // be able to walk the stack properly. This is not an issue except 231 // when there are mistakes in this assembly code that could generate 232 // a spurious fault. Ask me how I know... 233 234 // method (rbx): Method* 235 // j_rarg0: receiver 236 237 #ifdef ASSERT 238 if (DebugVtables) { 239 Label L2; 240 __ cmpptr(method, (int32_t)NULL_WORD); 241 __ jcc(Assembler::equal, L2); 242 __ cmpptr(Address(method, entry_offset), (int32_t)NULL_WORD); 243 __ jcc(Assembler::notZero, L2); 244 __ stop("compiler entrypoint is null"); 245 __ bind(L2); 246 } 247 #endif // ASSERT 248 249 address ame_addr = __ pc(); 250 __ jmp(Address(method, entry_offset)); 251 252 __ bind(L_no_such_interface); 253 // Handle IncompatibleClassChangeError in itable stubs. 254 // More detailed error message. 255 // We force resolving of the call site by jumping to the "handle 256 // wrong method" stub, and so let the interpreter runtime do all the 257 // dirty work. 258 __ jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub())); 259 260 masm->flush(); 261 slop_bytes += index_dependent_slop; // add'l slop for size variance due to large itable offsets 262 bookkeeping(masm, tty, s, npe_addr, ame_addr, false, itable_index, slop_bytes, index_dependent_slop); 263 264 return s; 265 } 266 267 int VtableStub::pd_code_alignment() { 268 // x86 cache line size is 64 bytes, but we want to limit alignment loss. 269 const unsigned int icache_line_size = wordSize; 270 return icache_line_size; 271 }