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 #ifdef SPARC
  45     // %%%%% Callee-save floats will NOT be working on a Sparc until we
  46     // handle the case of a 2 floats in a single double register.
  47     assert( !(loc.is_register() && loc.type() == Location::float_in_dbl), "Sparc does not handle callee-save floats yet" );
  48 #endif // SPARC
  49 
  50     // First find address of value
  51 
  52     address value_addr = loc.is_register()
  53       // Value was in a callee-save register
  54       ? reg_map->location(VMRegImpl::as_VMReg(loc.register_number()))
  55       // Else value was directly saved on the stack. The frame's original stack pointer,
  56       // before any extension by its callee (due to Compiler1 linkage on SPARC), must be used.
  57       : ((address)fr->unextended_sp()) + loc.stack_offset();
  58 
  59     // Then package it right depending on type
  60     // Note: the transfer of the data is thru a union that contains
  61     // an intptr_t. This is because an interpreter stack slot is
  62     // really an intptr_t. The use of a union containing an intptr_t
  63     // ensures that on a 64 bit platform we have proper alignment
  64     // and that we store the value where the interpreter will expect
  65     // to find it (i.e. proper endian). Similarly on a 32bit platform
  66     // using the intptr_t ensures that when a value is larger than
  67     // a stack slot (jlong/jdouble) that we capture the proper part
  68     // of the value for the stack slot in question.
  69     //
  70     switch( loc.type() ) {
  71     case Location::float_in_dbl: { // Holds a float in a double register?
  72       // The callee has no clue whether the register holds a float,
  73       // double or is unused.  He always saves a double.  Here we know
  74       // a double was saved, but we only want a float back.  Narrow the
  75       // saved double to the float that the JVM wants.
  76       assert( loc.is_register(), "floats always saved to stack in 1 word" );
  77       union { intptr_t p; jfloat jf; } value;
  78       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
  79       value.jf = (jfloat) *(jdouble*) value_addr;
  80       return new StackValue(value.p); // 64-bit high half is stack junk
  81     }
  82     case Location::int_in_long: { // Holds an int in a long register?
  83       // The callee has no clue whether the register holds an int,
  84       // long or is unused.  He always saves a long.  Here we know
  85       // a long was saved, but we only want an int back.  Narrow the
  86       // saved long to the int that the JVM wants.
  87       assert( loc.is_register(), "ints always saved to stack in 1 word" );
  88       union { intptr_t p; jint ji;} value;
  89       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
  90       value.ji = (jint) *(jlong*) value_addr;
  91       return new StackValue(value.p); // 64-bit high half is stack junk
  92     }
  93 #ifdef _LP64
  94     case Location::dbl:
  95       // Double value in an aligned adjacent pair
  96       return new StackValue(*(intptr_t*)value_addr);
  97     case Location::lng:
  98       // Long   value in an aligned adjacent pair
  99       return new StackValue(*(intptr_t*)value_addr);
 100     case Location::narrowoop: {
 101       union { intptr_t p; narrowOop noop;} value;
 102       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 103       if (loc.is_register()) {
 104         // The callee has no clue whether the register holds an int,
 105         // long or is unused.  He always saves a long.  Here we know
 106         // a long was saved, but we only want an int back.  Narrow the
 107         // saved long to the int that the JVM wants.
 108         value.noop =  (narrowOop) *(julong*) value_addr;
 109       } else {
 110         value.noop = *(narrowOop*) value_addr;
 111       }
 112       // Decode narrowoop
 113       oop val = CompressedOops::decode(value.noop);
 114       // Deoptimization must make sure all oops have passed load barriers
 115 #if INCLUDE_SHENANDOAHGC
 116       if (UseShenandoahGC) {
 117         val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
 118       }
 119 #endif
 120       Handle h(Thread::current(), val); // Wrap a handle around the oop
 121       return new StackValue(h);
 122     }
 123 #endif
 124     case Location::oop: {
 125       oop val = *(oop *)value_addr;
 126 #ifdef _LP64
 127       if (CompressedOops::is_base(val)) {
 128          // Compiled code may produce decoded oop = narrow_oop_base
 129          // when a narrow oop implicit null check is used.
 130          // The narrow_oop_base could be NULL or be the address
 131          // of the page below heap. Use NULL value for both cases.
 132          val = (oop)NULL;
 133       }
 134 #endif
 135       // Deoptimization must make sure all oops have passed load barriers
 136 #if INCLUDE_SHENANDOAHGC
 137       if (UseShenandoahGC) {
 138         val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
 139       }
 140 #endif
 141       assert(oopDesc::is_oop_or_null(val, false), "bad oop found");
 142       Handle h(Thread::current(), val); // Wrap a handle around the oop
 143       return new StackValue(h);
 144     }
 145     case Location::addr: {
 146       ShouldNotReachHere(); // both C1 and C2 now inline jsrs
 147     }
 148     case Location::normal: {
 149       // Just copy all other bits straight through
 150       union { intptr_t p; jint ji;} value;
 151       value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 152       value.ji = *(jint*)value_addr;
 153       return new StackValue(value.p);
 154     }
 155     case Location::invalid:
 156       return new StackValue();
 157     default:
 158       ShouldNotReachHere();
 159     }
 160 
 161   } else if (sv->is_constant_int()) {
 162     // Constant int: treat same as register int.
 163     union { intptr_t p; jint ji;} value;
 164     value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 165     value.ji = (jint)((ConstantIntValue*)sv)->value();
 166     return new StackValue(value.p);
 167   } else if (sv->is_constant_oop()) {
 168     // constant oop
 169     return new StackValue(sv->as_ConstantOopReadValue()->value());
 170 #ifdef _LP64
 171   } else if (sv->is_constant_double()) {
 172     // Constant double in a single stack slot
 173     union { intptr_t p; double d; } value;
 174     value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 175     value.d = ((ConstantDoubleValue *)sv)->value();
 176     return new StackValue(value.p);
 177   } else if (sv->is_constant_long()) {
 178     // Constant long in a single stack slot
 179     union { intptr_t p; jlong jl; } value;
 180     value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
 181     value.jl = ((ConstantLongValue *)sv)->value();
 182     return new StackValue(value.p);
 183 #endif
 184   } else if (sv->is_object()) { // Scalar replaced object in compiled frame
 185     Handle ov = ((ObjectValue *)sv)->value();
 186     return new StackValue(ov, (ov.is_null()) ? 1 : 0);
 187   }
 188 
 189   // Unknown ScopeValue type
 190   ShouldNotReachHere();
 191   return new StackValue((intptr_t) 0);   // dummy
 192 }
 193 
 194 
 195 BasicLock* StackValue::resolve_monitor_lock(const frame* fr, Location location) {
 196   assert(location.is_stack(), "for now we only look at the stack");
 197   int word_offset = location.stack_offset() / wordSize;
 198   // (stack picture)
 199   // high: [     ]  word_offset + 1
 200   // low   [     ]  word_offset
 201   //
 202   // sp->  [     ]  0
 203   // the word_offset is the distance from the stack pointer to the lowest address
 204   // The frame's original stack pointer, before any extension by its callee
 205   // (due to Compiler1 linkage on SPARC), must be used.
 206   return (BasicLock*) (fr->unextended_sp() + word_offset);
 207 }
 208 
 209 
 210 #ifndef PRODUCT
 211 
 212 void StackValue::print_on(outputStream* st) const {
 213   switch(_type) {
 214     case T_INT:
 215       st->print("%d (int) %f (float) %x (hex)",  *(int *)&_integer_value, *(float *)&_integer_value,  *(int *)&_integer_value);
 216       break;
 217 
 218     case T_OBJECT:
 219       if (_handle_value() != NULL) {
 220         _handle_value()->print_value_on(st);
 221       } else {
 222         st->print("NULL");
 223       }
 224       st->print(" <" INTPTR_FORMAT ">", p2i((address)_handle_value()));
 225      break;
 226 
 227     case T_CONFLICT:
 228      st->print("conflict");
 229      break;
 230 
 231     default:
 232      ShouldNotReachHere();
 233   }
 234 }
 235 
 236 #endif