1 /*
   2  * Copyright (c) 1997, 2017, 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 "code/debugInfo.hpp"
  27 #include "oops/compressedOops.inline.hpp"
  28 #include "oops/oop.hpp"
  29 #include "runtime/frame.inline.hpp"
  30 #include "runtime/handles.inline.hpp"
  31 #include "runtime/stackValue.hpp"
  32 #if INCLUDE_ZGC
  33 #include "gc/z/zBarrier.inline.hpp"
  34 #endif
  35 #if INCLUDE_SHENANDOAHGC
  36 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
  37 #endif
  38 
  39 StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv) {
  40   if (sv->is_location()) {
  41     // Stack or register value
  42     Location loc = ((LocationValue *)sv)->location();
  43 
  44     // First find address of value
  45 
  46     address value_addr = loc.is_register()
  47       // Value was in a callee-save register
  48       ? reg_map->location(VMRegImpl::as_VMReg(loc.register_number()))
  49       // Else value was directly saved on the stack. The frame's original stack pointer,
  50       // before any extension by its callee (due to Compiler1 linkage on SPARC), must be used.
  51       : ((address)fr->unextended_sp()) + loc.stack_offset();
  52 
  53     // Then package it right depending on type
  54     // Note: the transfer of the data is thru a union that contains
  55     // an intptr_t. This is because an interpreter stack slot is
  56     // really an intptr_t. The use of a union containing an intptr_t
  57     // ensures that on a 64 bit platform we have proper alignment
  58     // and that we store the value where the interpreter will expect
  59     // to find it (i.e. proper endian). Similarly on a 32bit platform
  60     // using the intptr_t ensures that when a value is larger than
  61     // a stack slot (jlong/jdouble) that we capture the proper part
  62     // of the value for the stack slot in question.
  63     //
  64     switch( loc.type() ) {
  65     case Location::float_in_dbl: { // Holds a float in a double register?
  66       // The callee has no clue whether the register holds a float,
  67       // double or is unused.  He always saves a double.  Here we know
  68       // a double was saved, but we only want a float back.  Narrow the
  69       // saved double to the float that the JVM wants.
  70       assert( loc.is_register(), "floats always saved to stack in 1 word" );
  71       union { intptr_t p; jfloat jf; } value;
  72       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
  73       value.jf = (jfloat) *(jdouble*) value_addr;
  74       return new StackValue(value.p); // 64-bit high half is stack junk
  75     }
  76     case Location::int_in_long: { // Holds an int in a long register?
  77       // The callee has no clue whether the register holds an int,
  78       // long or is unused.  He always saves a long.  Here we know
  79       // a long was saved, but we only want an int back.  Narrow the
  80       // saved long to the int that the JVM wants.
  81       assert( loc.is_register(), "ints always saved to stack in 1 word" );
  82       union { intptr_t p; jint ji;} value;
  83       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
  84       value.ji = (jint) *(jlong*) value_addr;
  85       return new StackValue(value.p); // 64-bit high half is stack junk
  86     }
  87 #ifdef _LP64
  88     case Location::dbl:
  89       // Double value in an aligned adjacent pair
  90       return new StackValue(*(intptr_t*)value_addr);
  91     case Location::lng:
  92       // Long   value in an aligned adjacent pair
  93       return new StackValue(*(intptr_t*)value_addr);
  94     case Location::narrowoop: {
  95       union { intptr_t p; narrowOop noop;} value;
  96       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
  97       if (loc.is_register()) {
  98         // The callee has no clue whether the register holds an int,
  99         // long or is unused.  He always saves a long.  Here we know
 100         // a long was saved, but we only want an int back.  Narrow the
 101         // saved long to the int that the JVM wants.
 102         value.noop =  (narrowOop) *(julong*) value_addr;
 103       } else {
 104         value.noop = *(narrowOop*) value_addr;
 105       }
 106       // Decode narrowoop
 107       oop val = CompressedOops::decode(value.noop);
 108       // Deoptimization must make sure all oops have passed load barriers
 109 #if INCLUDE_SHENANDOAHGC
 110       if (UseShenandoahGC) {
 111         val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
 112       }
 113 #endif
 114       Handle h(Thread::current(), val); // Wrap a handle around the oop
 115       return new StackValue(h);
 116     }
 117 #endif
 118     case Location::oop: {
 119       oop val = *(oop *)value_addr;
 120 #ifdef _LP64
 121       if (CompressedOops::is_base(val)) {
 122          // Compiled code may produce decoded oop = narrow_oop_base
 123          // when a narrow oop implicit null check is used.
 124          // The narrow_oop_base could be NULL or be the address
 125          // of the page below heap. Use NULL value for both cases.
 126          val = (oop)NULL;
 127       }
 128 #endif
 129       // Deoptimization must make sure all oops have passed load barriers
 130 #if INCLUDE_SHENANDOAHGC
 131       if (UseShenandoahGC) {
 132         val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
 133       }
 134 #endif
 135       assert(oopDesc::is_oop_or_null(val, false), "bad oop found");
 136       Handle h(Thread::current(), val); // Wrap a handle around the oop
 137       return new StackValue(h);
 138     }
 139     case Location::addr: {
 140       ShouldNotReachHere(); // both C1 and C2 now inline jsrs
 141     }
 142     case Location::normal: {
 143       // Just copy all other bits straight through
 144       union { intptr_t p; jint ji;} value;
 145       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 146       value.ji = *(jint*)value_addr;
 147       return new StackValue(value.p);
 148     }
 149     case Location::invalid:
 150       return new StackValue();
 151     default:
 152       ShouldNotReachHere();
 153     }
 154 
 155   } else if (sv->is_constant_int()) {
 156     // Constant int: treat same as register int.
 157     union { intptr_t p; jint ji;} value;
 158     value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 159     value.ji = (jint)((ConstantIntValue*)sv)->value();
 160     return new StackValue(value.p);
 161   } else if (sv->is_constant_oop()) {
 162     // constant oop
 163     return new StackValue(sv->as_ConstantOopReadValue()->value());
 164 #ifdef _LP64
 165   } else if (sv->is_constant_double()) {
 166     // Constant double in a single stack slot
 167     union { intptr_t p; double d; } value;
 168     value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 169     value.d = ((ConstantDoubleValue *)sv)->value();
 170     return new StackValue(value.p);
 171   } else if (sv->is_constant_long()) {
 172     // Constant long in a single stack slot
 173     union { intptr_t p; jlong jl; } value;
 174     value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 175     value.jl = ((ConstantLongValue *)sv)->value();
 176     return new StackValue(value.p);
 177 #endif
 178   } else if (sv->is_object()) { // Scalar replaced object in compiled frame
 179     Handle ov = ((ObjectValue *)sv)->value();
 180     return new StackValue(ov, (ov.is_null()) ? 1 : 0);
 181   } else if (sv->is_marker()) {
 182     // Should never need to directly construct a marker.
 183     ShouldNotReachHere();
 184   }
 185   // Unknown ScopeValue type
 186   ShouldNotReachHere();
 187   return new StackValue((intptr_t) 0);   // dummy
 188 }
 189 
 190 
 191 BasicLock* StackValue::resolve_monitor_lock(const frame* fr, Location location) {
 192   assert(location.is_stack(), "for now we only look at the stack");
 193   int word_offset = location.stack_offset() / wordSize;
 194   // (stack picture)
 195   // high: [     ]  word_offset + 1
 196   // low   [     ]  word_offset
 197   //
 198   // sp->  [     ]  0
 199   // the word_offset is the distance from the stack pointer to the lowest address
 200   // The frame's original stack pointer, before any extension by its callee
 201   // (due to Compiler1 linkage on SPARC), must be used.
 202   return (BasicLock*) (fr->unextended_sp() + word_offset);
 203 }
 204 
 205 
 206 #ifndef PRODUCT
 207 
 208 void StackValue::print_on(outputStream* st) const {
 209   switch(_type) {
 210     case T_INT:
 211       st->print("%d (int) %f (float) %x (hex)",  *(int *)&_integer_value, *(float *)&_integer_value,  *(int *)&_integer_value);
 212       break;
 213 
 214     case T_OBJECT:
 215       if (_handle_value() != NULL) {
 216         _handle_value()->print_value_on(st);
 217       } else {
 218         st->print("NULL");
 219       }
 220       st->print(" <" INTPTR_FORMAT ">", p2i(_handle_value()));
 221      break;
 222 
 223     case T_CONFLICT:
 224      st->print("conflict");
 225      break;
 226 
 227     default:
 228      ShouldNotReachHere();
 229   }
 230 }
 231 
 232 #endif