1 /*
   2  * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2014, Red Hat Inc. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "asm/macroAssembler.inline.hpp"
  28 #include "assembler_aarch64.inline.hpp"
  29 #include "code/vtableStubs.hpp"
  30 #include "interp_masm_aarch64.hpp"
  31 #include "memory/resourceArea.hpp"
  32 #include "oops/compiledICHolder.hpp"
  33 #include "oops/instanceKlass.hpp"
  34 #include "oops/klassVtable.hpp"
  35 #include "runtime/sharedRuntime.hpp"
  36 #include "vmreg_aarch64.inline.hpp"
  37 #ifdef COMPILER2
  38 #include "opto/runtime.hpp"
  39 #endif
  40 
  41 // machine-dependent part of VtableStubs: create VtableStub of correct size and
  42 // initialize its code
  43 
  44 #define __ masm->
  45 
  46 #ifndef PRODUCT
  47 extern "C" void bad_compiled_vtable_index(JavaThread* thread, oop receiver, int index);
  48 #endif
  49 
  50 VtableStub* VtableStubs::create_vtable_stub(int vtable_index) {
  51   // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
  52   const int stub_code_length = code_size_limit(true);
  53   VtableStub* s = new(stub_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   // Count unused bytes in instruction sequences of variable size.
  60   // We add them to the computed buffer size in order to avoid
  61   // overflow in subsequently generated stubs.
  62   address   start_pc;
  63   int       slop_bytes = 0;
  64   int       slop_delta = 0;
  65 
  66   ResourceMark    rm;
  67   CodeBuffer      cb(s->entry_point(), stub_code_length);
  68   MacroAssembler* masm = new MacroAssembler(&cb);
  69 
  70 #if (!defined(PRODUCT) && defined(COMPILER2))
  71   if (CountCompiledCalls) {
  72     __ lea(r16, ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
  73     __ incrementw(Address(r16));
  74   }
  75 #endif
  76 
  77   // get receiver (need to skip return address on top of stack)
  78   assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
  79 
  80   // get receiver klass
  81   address npe_addr = __ pc();
  82   __ load_klass(r16, j_rarg0);
  83 
  84 #ifndef PRODUCT
  85   if (DebugVtables) {
  86     Label L;
  87     // TODO: find upper bound for this debug code.
  88     start_pc = __ pc();
  89 
  90     // check offset vs vtable length
  91     __ ldrw(rscratch1, Address(r16, Klass::vtable_length_offset()));
  92     __ cmpw(rscratch1, vtable_index * vtableEntry::size());
  93     __ br(Assembler::GT, L);
  94     __ enter();
  95     __ mov(r2, vtable_index);
  96 
  97     __ call_VM(noreg, CAST_FROM_FN_PTR(address, bad_compiled_vtable_index), j_rarg0, r2);
  98     const ptrdiff_t estimate = 256;
  99     const ptrdiff_t codesize = __ pc() - start_pc;
 100     slop_delta  = estimate - codesize;  // call_VM varies in length, depending on data
 101     slop_bytes += slop_delta;
 102     assert(slop_delta >= 0, "vtable #%d: Code size estimate (%d) for DebugVtables too small, required: %d", vtable_index, (int)estimate, (int)codesize);
 103 
 104     __ leave();
 105     __ bind(L);
 106   }
 107 #endif // PRODUCT
 108 
 109   start_pc = __ pc();
 110   __ lookup_virtual_method(r16, vtable_index, rmethod);
 111   slop_delta  = 8 - (int)(__ pc() - start_pc);
 112   slop_bytes += slop_delta;
 113   assert(slop_delta >= 0, "negative slop(%d) encountered, adjust code size estimate!", slop_delta);
 114 
 115 #ifndef PRODUCT
 116   if (DebugVtables) {
 117     Label L;
 118     __ cbz(rmethod, L);
 119     __ ldr(rscratch1, Address(rmethod, Method::from_compiled_value_ro_offset()));
 120     __ cbnz(rscratch1, L);
 121     __ stop("Vtable entry is NULL");
 122     __ bind(L);
 123   }
 124 #endif // PRODUCT
 125 
 126   // r0: receiver klass
 127   // rmethod: Method*
 128   // r2: receiver
 129   address ame_addr = __ pc();
 130   __ ldr(rscratch1, Address(rmethod, Method::from_compiled_value_ro_offset()));
 131   __ br(rscratch1);
 132 
 133   masm->flush();
 134   bookkeeping(masm, tty, s, npe_addr, ame_addr, true, vtable_index, slop_bytes, 0);
 135 
 136   return s;
 137 }
 138 
 139 
 140 VtableStub* VtableStubs::create_itable_stub(int itable_index) {
 141   // Read "A word on VtableStub sizing" in share/code/vtableStubs.hpp for details on stub sizing.
 142   const int stub_code_length = code_size_limit(false);
 143   VtableStub* s = new(stub_code_length) VtableStub(false, itable_index);
 144   // Can be NULL if there is no free space in the code cache.
 145   if (s == NULL) {
 146     return NULL;
 147   }
 148   // Count unused bytes in instruction sequences of variable size.
 149   // We add them to the computed buffer size in order to avoid
 150   // overflow in subsequently generated stubs.
 151   address   start_pc;
 152   int       slop_bytes = 0;
 153   int       slop_delta = 0;
 154 
 155   ResourceMark    rm;
 156   CodeBuffer      cb(s->entry_point(), stub_code_length);
 157   MacroAssembler* masm = new MacroAssembler(&cb);
 158 
 159 #if (!defined(PRODUCT) && defined(COMPILER2))
 160   if (CountCompiledCalls) {
 161     __ lea(r10, ExternalAddress((address) SharedRuntime::nof_megamorphic_calls_addr()));
 162     __ incrementw(Address(r10));
 163   }
 164 #endif
 165 
 166   // get receiver (need to skip return address on top of stack)
 167   assert(VtableStub::receiver_location() == j_rarg0->as_VMReg(), "receiver expected in j_rarg0");
 168 
 169   // Entry arguments:
 170   //  rscratch2: CompiledICHolder
 171   //  j_rarg0: Receiver
 172 
 173   // Most registers are in use; we'll use r16, rmethod, r10, r11
 174   const Register recv_klass_reg     = r10;
 175   const Register holder_klass_reg   = r16; // declaring interface klass (DECC)
 176   const Register resolved_klass_reg = rmethod; // resolved interface klass (REFC)
 177   const Register temp_reg           = r11;
 178   const Register icholder_reg       = rscratch2;
 179 
 180   Label L_no_such_interface;
 181 
 182   __ ldr(resolved_klass_reg, Address(icholder_reg, CompiledICHolder::holder_klass_offset()));
 183   __ ldr(holder_klass_reg,   Address(icholder_reg, CompiledICHolder::holder_metadata_offset()));
 184 
 185   start_pc = __ pc();
 186 
 187   // get receiver klass (also an implicit null-check)
 188   address npe_addr = __ pc();
 189   __ load_klass(recv_klass_reg, j_rarg0);
 190 
 191   // Receiver subtype check against REFC.
 192   // Destroys recv_klass_reg value.
 193   __ lookup_interface_method(// inputs: rec. class, interface
 194                              recv_klass_reg, resolved_klass_reg, noreg,
 195                              // outputs:  scan temp. reg1, scan temp. reg2
 196                              recv_klass_reg, temp_reg,
 197                              L_no_such_interface,
 198                              /*return_method=*/false);
 199 
 200   const ptrdiff_t  typecheckSize = __ pc() - start_pc;
 201   start_pc = __ pc();
 202 
 203   // Get selected method from declaring class and itable index
 204   __ load_klass(recv_klass_reg, j_rarg0);   // restore recv_klass_reg
 205   __ lookup_interface_method(// inputs: rec. class, interface, itable index
 206                              recv_klass_reg, holder_klass_reg, itable_index,
 207                              // outputs: method, scan temp. reg
 208                              rmethod, temp_reg,
 209                              L_no_such_interface);
 210 
 211   const ptrdiff_t lookupSize = __ pc() - start_pc;
 212 
 213   // Reduce "estimate" such that "padding" does not drop below 8.
 214   const ptrdiff_t estimate = 152;
 215   const ptrdiff_t codesize = typecheckSize + lookupSize;
 216   slop_delta  = (int)(estimate - codesize);
 217   slop_bytes += slop_delta;
 218   assert(slop_delta >= 0, "itable #%d: Code size estimate (%d) for lookup_interface_method too small, required: %d", itable_index, (int)estimate, (int)codesize);
 219 
 220 #ifdef ASSERT
 221   if (DebugVtables) {
 222     Label L2;
 223     __ cbz(rmethod, L2);
 224     __ ldr(rscratch1, Address(rmethod, Method::from_compiled_offset()));
 225     __ cbnz(rscratch1, L2);
 226     __ stop("compiler entrypoint is null");
 227     __ bind(L2);
 228   }
 229 #endif // ASSERT
 230 
 231   // rmethod: Method*
 232   // j_rarg0: receiver
 233   address ame_addr = __ pc();
 234   __ ldr(rscratch1, Address(rmethod, Method::from_compiled_offset()));
 235   __ br(rscratch1);
 236 
 237   __ bind(L_no_such_interface);
 238   // Handle IncompatibleClassChangeError in itable stubs.
 239   // More detailed error message.
 240   // We force resolving of the call site by jumping to the "handle
 241   // wrong method" stub, and so let the interpreter runtime do all the
 242   // dirty work.
 243   assert(SharedRuntime::get_handle_wrong_method_stub() != NULL, "check initialization order");
 244   __ far_jump(RuntimeAddress(SharedRuntime::get_handle_wrong_method_stub()));
 245 
 246   masm->flush();
 247   bookkeeping(masm, tty, s, npe_addr, ame_addr, false, itable_index, slop_bytes, 0);
 248 
 249   return s;
 250 }
 251 
 252 int VtableStub::pd_code_alignment() {
 253   // aarch64 cache line size is not an architected constant. We just align on 4 bytes (instruction size).
 254   const unsigned int icache_line_size = 4;
 255   return icache_line_size;
 256 }