stackValue.cpp revision 6412:53a41e7cbe05 
1/*
2 * Copyright (c) 1997, 2014, 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
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23 */
24
25#include "precompiled.hpp"
26#include "code/debugInfo.hpp"
27#include "oops/oop.inline.hpp"
28#include "runtime/frame.inline.hpp"
29#include "runtime/handles.inline.hpp"
30#include "runtime/stackValue.hpp"
31
32StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv) {
33  if (sv->is_location()) {
34    // Stack or register value
35    Location loc = ((LocationValue *)sv)->location();
36
37#ifdef SPARC
38    // %%%%% Callee-save floats will NOT be working on a Sparc until we
39    // handle the case of a 2 floats in a single double register.
40    assert( !(loc.is_register() && loc.type() == Location::float_in_dbl), "Sparc does not handle callee-save floats yet" );
41#endif // SPARC
42
43    // First find address of value
44
45    address value_addr = loc.is_register()
46      // Value was in a callee-save register
47      ? reg_map->location(VMRegImpl::as_VMReg(loc.register_number()))
48      // Else value was directly saved on the stack. The frame's original stack pointer,
49      // before any extension by its callee (due to Compiler1 linkage on SPARC), must be used.
50      : ((address)fr->unextended_sp()) + loc.stack_offset();
51
52    // Then package it right depending on type
53    // Note: the transfer of the data is thru a union that contains
54    // an intptr_t. This is because an interpreter stack slot is
55    // really an intptr_t. The use of a union containing an intptr_t
56    // ensures that on a 64 bit platform we have proper alignment
57    // and that we store the value where the interpreter will expect
58    // to find it (i.e. proper endian). Similarly on a 32bit platform
59    // using the intptr_t ensures that when a value is larger than
60    // a stack slot (jlong/jdouble) that we capture the proper part
61    // of the value for the stack slot in question.
62    //
63    switch( loc.type() ) {
64    case Location::float_in_dbl: { // Holds a float in a double register?
65      // The callee has no clue whether the register holds a float,
66      // double or is unused.  He always saves a double.  Here we know
67      // a double was saved, but we only want a float back.  Narrow the
68      // saved double to the float that the JVM wants.
69      assert( loc.is_register(), "floats always saved to stack in 1 word" );
70      union { intptr_t p; jfloat jf; } value;
71      value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
72      value.jf = (jfloat) *(jdouble*) value_addr;
73      return new StackValue(value.p); // 64-bit high half is stack junk
74    }
75    case Location::int_in_long: { // Holds an int in a long register?
76      // The callee has no clue whether the register holds an int,
77      // long or is unused.  He always saves a long.  Here we know
78      // a long was saved, but we only want an int back.  Narrow the
79      // saved long to the int that the JVM wants.
80      assert( loc.is_register(), "ints always saved to stack in 1 word" );
81      union { intptr_t p; jint ji;} value;
82      value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
83      value.ji = (jint) *(jlong*) value_addr;
84      return new StackValue(value.p); // 64-bit high half is stack junk
85    }
86#ifdef _LP64
87    case Location::dbl:
88      // Double value in an aligned adjacent pair
89      return new StackValue(*(intptr_t*)value_addr);
90    case Location::lng:
91      // Long   value in an aligned adjacent pair
92      return new StackValue(*(intptr_t*)value_addr);
93    case Location::narrowoop: {
94      union { intptr_t p; narrowOop noop;} value;
95      value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
96      if (loc.is_register()) {
97        // The callee has no clue whether the register holds an int,
98        // long or is unused.  He always saves a long.  Here we know
99        // a long was saved, but we only want an int back.  Narrow the
100        // saved long to the int that the JVM wants.
101        value.noop =  (narrowOop) *(julong*) value_addr;
102      } else {
103        value.noop = *(narrowOop*) value_addr;
104      }
105      // Decode narrowoop and wrap a handle around the oop
106      Handle h(oopDesc::decode_heap_oop(value.noop));
107      return new StackValue(h);
108    }
109#endif
110    case Location::oop: {
111      oop val = *(oop *)value_addr;
112#ifdef _LP64
113      if (Universe::is_narrow_oop_base(val)) {
114         // Compiled code may produce decoded oop = narrow_oop_base
115         // when a narrow oop implicit null check is used.
116         // The narrow_oop_base could be NULL or be the address
117         // of the page below heap. Use NULL value for both cases.
118         val = (oop)NULL;
119      }
120#endif
121      Handle h(val); // Wrap a handle around the oop
122      return new StackValue(h);
123    }
124    case Location::addr: {
125      ShouldNotReachHere(); // both C1 and C2 now inline jsrs
126    }
127    case Location::normal: {
128      // Just copy all other bits straight through
129      union { intptr_t p; jint ji;} value;
130      value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
131      value.ji = *(jint*)value_addr;
132      return new StackValue(value.p);
133    }
134    case Location::invalid:
135      return new StackValue();
136    default:
137      ShouldNotReachHere();
138    }
139
140  } else if (sv->is_constant_int()) {
141    // Constant int: treat same as register int.
142    union { intptr_t p; jint ji;} value;
143    value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
144    value.ji = (jint)((ConstantIntValue*)sv)->value();
145    return new StackValue(value.p);
146  } else if (sv->is_constant_oop()) {
147    // constant oop
148    return new StackValue(sv->as_ConstantOopReadValue()->value());
149#ifdef _LP64
150  } else if (sv->is_constant_double()) {
151    // Constant double in a single stack slot
152    union { intptr_t p; double d; } value;
153    value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
154    value.d = ((ConstantDoubleValue *)sv)->value();
155    return new StackValue(value.p);
156  } else if (sv->is_constant_long()) {
157    // Constant long in a single stack slot
158    union { intptr_t p; jlong jl; } value;
159    value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
160    value.jl = ((ConstantLongValue *)sv)->value();
161    return new StackValue(value.p);
162#endif
163  } else if (sv->is_object()) { // Scalar replaced object in compiled frame
164    Handle ov = ((ObjectValue *)sv)->value();
165    return new StackValue(ov, (ov.is_null()) ? 1 : 0);
166  }
167
168  // Unknown ScopeValue type
169  ShouldNotReachHere();
170  return new StackValue((intptr_t) 0);   // dummy
171}
172
173
174BasicLock* StackValue::resolve_monitor_lock(const frame* fr, Location location) {
175  assert(location.is_stack(), "for now we only look at the stack");
176  int word_offset = location.stack_offset() / wordSize;
177  // (stack picture)
178  // high: [     ]  word_offset + 1
179  // low   [     ]  word_offset
180  //
181  // sp->  [     ]  0
182  // the word_offset is the distance from the stack pointer to the lowest address
183  // The frame's original stack pointer, before any extension by its callee
184  // (due to Compiler1 linkage on SPARC), must be used.
185  return (BasicLock*) (fr->unextended_sp() + word_offset);
186}
187
188
189#ifndef PRODUCT
190
191void StackValue::print_on(outputStream* st) const {
192  switch(_type) {
193    case T_INT:
194      st->print("%d (int) %f (float) %x (hex)",  *(int *)&_i, *(float *)&_i,  *(int *)&_i);
195      break;
196
197    case T_OBJECT:
198     _o()->print_value_on(st);
199      st->print(" <" INTPTR_FORMAT ">", p2i((address)_o()));
200     break;
201
202    case T_CONFLICT:
203     st->print("conflict");
204     break;
205
206    default:
207     ShouldNotReachHere();
208  }
209}
210
211#endif
212