1 /*
   2  * Copyright (c) 2018, 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 "c1/c1_Defs.hpp"
  27 #include "c1/c1_LIRGenerator.hpp"
  28 #include "gc/shared/c1/barrierSetC1.hpp"
  29 #include "utilities/macros.hpp"
  30 
  31 #ifndef PATCHED_ADDR
  32 #define PATCHED_ADDR  (max_jint)
  33 #endif
  34 
  35 #ifdef ASSERT
  36 #define __ gen->lir(__FILE__, __LINE__)->
  37 #else
  38 #define __ gen->lir()->
  39 #endif
  40 
  41 LIR_Opr BarrierSetC1::resolve_address(LIRAccess& access, bool resolve_in_register) {
  42   DecoratorSet decorators = access.decorators();
  43   bool is_array = (decorators & IS_ARRAY) != 0;
  44   bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
  45 
  46   LIRItem& base = access.base().item();
  47   LIR_Opr offset = access.offset().opr();
  48   LIRGenerator *gen = access.gen();
  49 
  50   LIR_Opr addr_opr;
  51   if (is_array) {
  52     addr_opr = LIR_OprFact::address(gen->emit_array_address(base.result(), offset, access.type()));
  53   } else if (needs_patching) {
  54     // we need to patch the offset in the instruction so don't allow
  55     // generate_address to try to be smart about emitting the -1.
  56     // Otherwise the patching code won't know how to find the
  57     // instruction to patch.
  58     addr_opr = LIR_OprFact::address(new LIR_Address(base.result(), PATCHED_ADDR, access.type()));
  59   } else {
  60     addr_opr = LIR_OprFact::address(gen->generate_address(base.result(), offset, 0, 0, access.type()));
  61   }
  62 
  63   if (resolve_in_register) {
  64     LIR_Opr resolved_addr = gen->new_pointer_register();
  65     if (needs_patching) {
  66       __ leal(addr_opr, resolved_addr, lir_patch_normal, access.patch_emit_info());
  67       access.clear_decorators(C1_NEEDS_PATCHING);
  68     } else {
  69       __ leal(addr_opr, resolved_addr);
  70     }
  71     return LIR_OprFact::address(new LIR_Address(resolved_addr, access.type()));
  72   } else {
  73     return addr_opr;
  74   }
  75 }
  76 
  77 void BarrierSetC1::store_at(LIRAccess& access, LIR_Opr value) {
  78   DecoratorSet decorators = access.decorators();
  79   bool in_heap = (decorators & IN_HEAP) != 0;
  80   assert(in_heap, "not supported yet");
  81 
  82   LIR_Opr resolved = resolve_address(access, false);
  83   access.set_resolved_addr(resolved);
  84   store_at_resolved(access, value);
  85 }
  86 
  87 void BarrierSetC1::load_at(LIRAccess& access, LIR_Opr result) {
  88   DecoratorSet decorators = access.decorators();
  89   bool in_heap = (decorators & IN_HEAP) != 0;
  90   assert(in_heap, "not supported yet");
  91 
  92   LIR_Opr resolved = resolve_address(access, false);
  93   access.set_resolved_addr(resolved);
  94   load_at_resolved(access, result);
  95 }
  96 
  97 void BarrierSetC1::load(LIRAccess& access, LIR_Opr result) {
  98   DecoratorSet decorators = access.decorators();
  99   bool in_heap = (decorators & IN_HEAP) != 0;
 100   assert(!in_heap, "consider using load_at");
 101   load_at_resolved(access, result);
 102 }
 103 
 104 LIR_Opr BarrierSetC1::atomic_cmpxchg_at(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
 105   DecoratorSet decorators = access.decorators();
 106   bool in_heap = (decorators & IN_HEAP) != 0;
 107   assert(in_heap, "not supported yet");
 108 
 109   access.load_address();
 110 
 111   LIR_Opr resolved = resolve_address(access, true);
 112   access.set_resolved_addr(resolved);
 113   return atomic_cmpxchg_at_resolved(access, cmp_value, new_value);
 114 }
 115 
 116 LIR_Opr BarrierSetC1::atomic_xchg_at(LIRAccess& access, LIRItem& value) {
 117   DecoratorSet decorators = access.decorators();
 118   bool in_heap = (decorators & IN_HEAP) != 0;
 119   assert(in_heap, "not supported yet");
 120 
 121   access.load_address();
 122 
 123   LIR_Opr resolved = resolve_address(access, true);
 124   access.set_resolved_addr(resolved);
 125   return atomic_xchg_at_resolved(access, value);
 126 }
 127 
 128 LIR_Opr BarrierSetC1::atomic_add_at(LIRAccess& access, LIRItem& value) {
 129   DecoratorSet decorators = access.decorators();
 130   bool in_heap = (decorators & IN_HEAP) != 0;
 131   assert(in_heap, "not supported yet");
 132 
 133   access.load_address();
 134 
 135   LIR_Opr resolved = resolve_address(access, true);
 136   access.set_resolved_addr(resolved);
 137   return atomic_add_at_resolved(access, value);
 138 }
 139 
 140 void BarrierSetC1::store_at_resolved(LIRAccess& access, LIR_Opr value) {
 141   DecoratorSet decorators = access.decorators();
 142   bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses);
 143   bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
 144   bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
 145   LIRGenerator* gen = access.gen();
 146 
 147   if (mask_boolean) {
 148     value = gen->mask_boolean(access.base().opr(), value, access.access_emit_info());
 149   }
 150 
 151   if (is_volatile) {
 152     __ membar_release();
 153   }
 154 
 155   LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
 156   if (is_volatile && !needs_patching) {
 157     gen->volatile_field_store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info());
 158   } else {
 159     __ store(value, access.resolved_addr()->as_address_ptr(), access.access_emit_info(), patch_code);
 160   }
 161 
 162   if (is_volatile && !support_IRIW_for_not_multiple_copy_atomic_cpu) {
 163     __ membar();
 164   }
 165 }
 166 
 167 void BarrierSetC1::load_at_resolved(LIRAccess& access, LIR_Opr result) {
 168   LIRGenerator *gen = access.gen();
 169   DecoratorSet decorators = access.decorators();
 170   bool is_volatile = (((decorators & MO_SEQ_CST) != 0) || AlwaysAtomicAccesses);
 171   bool needs_patching = (decorators & C1_NEEDS_PATCHING) != 0;
 172   bool mask_boolean = (decorators & C1_MASK_BOOLEAN) != 0;
 173   bool in_native = (decorators & IN_NATIVE) != 0;
 174 
 175   if (support_IRIW_for_not_multiple_copy_atomic_cpu && is_volatile) {
 176     __ membar();
 177   }
 178 
 179   LIR_PatchCode patch_code = needs_patching ? lir_patch_normal : lir_patch_none;
 180   if (in_native) {
 181     __ move_wide(access.resolved_addr()->as_address_ptr(), result);
 182   } else if (is_volatile && !needs_patching) {
 183     gen->volatile_field_load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info());
 184   } else {
 185     __ load(access.resolved_addr()->as_address_ptr(), result, access.access_emit_info(), patch_code);
 186   }
 187 
 188   if (is_volatile) {
 189     __ membar_acquire();
 190   }
 191 
 192   /* Normalize boolean value returned by unsafe operation, i.e., value  != 0 ? value = true : value false. */
 193   if (mask_boolean) {
 194     LabelObj* equalZeroLabel = new LabelObj();
 195     __ cmp(lir_cond_equal, result, 0);
 196     __ branch(lir_cond_equal, T_BOOLEAN, equalZeroLabel->label());
 197     __ move(LIR_OprFact::intConst(1), result);
 198     __ branch_destination(equalZeroLabel->label());
 199   }
 200 }
 201 
 202 LIR_Opr BarrierSetC1::atomic_cmpxchg_at_resolved(LIRAccess& access, LIRItem& cmp_value, LIRItem& new_value) {
 203   LIRGenerator *gen = access.gen();
 204   return gen->atomic_cmpxchg(access.type(), access.resolved_addr(), cmp_value, new_value);
 205 }
 206 
 207 LIR_Opr BarrierSetC1::atomic_xchg_at_resolved(LIRAccess& access, LIRItem& value) {
 208   LIRGenerator *gen = access.gen();
 209   return gen->atomic_xchg(access.type(), access.resolved_addr(), value);
 210 }
 211 
 212 LIR_Opr BarrierSetC1::atomic_add_at_resolved(LIRAccess& access, LIRItem& value) {
 213   LIRGenerator *gen = access.gen();
 214   return gen->atomic_add(access.type(), access.resolved_addr(), value);
 215 }
 216 
 217 void BarrierSetC1::generate_referent_check(LIRAccess& access, LabelObj* cont) {
 218   // We might be reading the value of the referent field of a
 219   // Reference object in order to attach it back to the live
 220   // object graph. If G1 is enabled then we need to record
 221   // the value that is being returned in an SATB log buffer.
 222   //
 223   // We need to generate code similar to the following...
 224   //
 225   // if (offset == java_lang_ref_Reference::referent_offset) {
 226   //   if (src != NULL) {
 227   //     if (klass(src)->reference_type() != REF_NONE) {
 228   //       pre_barrier(..., value, ...);
 229   //     }
 230   //   }
 231   // }
 232 
 233   bool gen_pre_barrier = true;     // Assume we need to generate pre_barrier.
 234   bool gen_offset_check = true;    // Assume we need to generate the offset guard.
 235   bool gen_source_check = true;    // Assume we need to check the src object for null.
 236   bool gen_type_check = true;      // Assume we need to check the reference_type.
 237 
 238   LIRGenerator *gen = access.gen();
 239 
 240   LIRItem& base = access.base().item();
 241   LIR_Opr offset = access.offset().opr();
 242 
 243   if (offset->is_constant()) {
 244     LIR_Const* constant = offset->as_constant_ptr();
 245     jlong off_con = (constant->type() == T_INT ?
 246                      (jlong)constant->as_jint() :
 247                      constant->as_jlong());
 248 
 249 
 250     if (off_con != (jlong) java_lang_ref_Reference::referent_offset) {
 251       // The constant offset is something other than referent_offset.
 252       // We can skip generating/checking the remaining guards and
 253       // skip generation of the code stub.
 254       gen_pre_barrier = false;
 255     } else {
 256       // The constant offset is the same as referent_offset -
 257       // we do not need to generate a runtime offset check.
 258       gen_offset_check = false;
 259     }
 260   }
 261 
 262   // We don't need to generate stub if the source object is an array
 263   if (gen_pre_barrier && base.type()->is_array()) {
 264     gen_pre_barrier = false;
 265   }
 266 
 267   if (gen_pre_barrier) {
 268     // We still need to continue with the checks.
 269     if (base.is_constant()) {
 270       ciObject* src_con = base.get_jobject_constant();
 271       guarantee(src_con != NULL, "no source constant");
 272 
 273       if (src_con->is_null_object()) {
 274         // The constant src object is null - We can skip
 275         // generating the code stub.
 276         gen_pre_barrier = false;
 277       } else {
 278         // Non-null constant source object. We still have to generate
 279         // the slow stub - but we don't need to generate the runtime
 280         // null object check.
 281         gen_source_check = false;
 282       }
 283     }
 284   }
 285   if (gen_pre_barrier && !PatchALot) {
 286     // Can the klass of object be statically determined to be
 287     // a sub-class of Reference?
 288     ciType* type = base.value()->declared_type();
 289     if ((type != NULL) && type->is_loaded()) {
 290       if (type->is_subtype_of(gen->compilation()->env()->Reference_klass())) {
 291         gen_type_check = false;
 292       } else if (type->is_klass() &&
 293                  !gen->compilation()->env()->Object_klass()->is_subtype_of(type->as_klass())) {
 294         // Not Reference and not Object klass.
 295         gen_pre_barrier = false;
 296       }
 297     }
 298   }
 299 
 300   if (gen_pre_barrier) {
 301     // We can have generate one runtime check here. Let's start with
 302     // the offset check.
 303     // Allocate temp register to base and load it here, otherwise
 304     // control flow below may confuse register allocator.
 305     LIR_Opr base_reg = gen->new_register(T_OBJECT);
 306     __ move(base.result(), base_reg);
 307     if (gen_offset_check) {
 308       // if (offset != referent_offset) -> continue
 309       // If offset is an int then we can do the comparison with the
 310       // referent_offset constant; otherwise we need to move
 311       // referent_offset into a temporary register and generate
 312       // a reg-reg compare.
 313 
 314       LIR_Opr referent_off;
 315 
 316       if (offset->type() == T_INT) {
 317         referent_off = LIR_OprFact::intConst(java_lang_ref_Reference::referent_offset);
 318       } else {
 319         assert(offset->type() == T_LONG, "what else?");
 320         referent_off = gen->new_register(T_LONG);
 321         __ move(LIR_OprFact::longConst(java_lang_ref_Reference::referent_offset), referent_off);
 322       }
 323       __ cmp(lir_cond_notEqual, offset, referent_off);
 324       __ branch(lir_cond_notEqual, offset->type(), cont->label());
 325     }
 326     if (gen_source_check) {
 327       // offset is a const and equals referent offset
 328       // if (source == null) -> continue
 329       __ cmp(lir_cond_equal, base_reg, LIR_OprFact::oopConst(NULL));
 330       __ branch(lir_cond_equal, T_OBJECT, cont->label());
 331     }
 332     LIR_Opr src_klass = gen->new_register(T_METADATA);
 333     if (gen_type_check) {
 334       // We have determined that offset == referent_offset && src != null.
 335       // if (src->_klass->_reference_type == REF_NONE) -> continue
 336       __ move(new LIR_Address(base_reg, oopDesc::klass_offset_in_bytes(), T_ADDRESS), src_klass);
 337       LIR_Address* reference_type_addr = new LIR_Address(src_klass, in_bytes(InstanceKlass::reference_type_offset()), T_BYTE);
 338       LIR_Opr reference_type = gen->new_register(T_INT);
 339       __ move(reference_type_addr, reference_type);
 340       __ cmp(lir_cond_equal, reference_type, LIR_OprFact::intConst(REF_NONE));
 341       __ branch(lir_cond_equal, T_INT, cont->label());
 342     }
 343   }
 344 }
 345 
 346 LIR_Opr BarrierSetC1::resolve(LIRGenerator* gen, DecoratorSet decorators, LIR_Opr obj) {
 347   return obj;
 348 }