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 (Universe::is_narrow_oop_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_ZGC
137 if (UseZGC) {
138 val = ZBarrier::load_barrier_on_oop_field_preloaded((oop*)value_addr, val);
139 }
140 #endif
141 #if INCLUDE_SHENANDOAHGC
142 if (UseShenandoahGC) {
143 val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
144 }
145 #endif
146 Handle h(Thread::current(), val); // Wrap a handle around the oop
147 return new StackValue(h);
148 }
149 case Location::addr: {
150 ShouldNotReachHere(); // both C1 and C2 now inline jsrs
151 }
152 case Location::normal: {
153 // Just copy all other bits straight through
154 union { intptr_t p; jint ji;} value;
155 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
156 value.ji = *(jint*)value_addr;
157 return new StackValue(value.p);
158 }
159 case Location::invalid:
160 return new StackValue();
161 default:
162 ShouldNotReachHere();
163 }
164
165 } else if (sv->is_constant_int()) {
166 // Constant int: treat same as register int.
167 union { intptr_t p; jint ji;} value;
168 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
169 value.ji = (jint)((ConstantIntValue*)sv)->value();
170 return new StackValue(value.p);
171 } else if (sv->is_constant_oop()) {
172 // constant oop
173 return new StackValue(sv->as_ConstantOopReadValue()->value());
174 #ifdef _LP64
175 } else if (sv->is_constant_double()) {
176 // Constant double in a single stack slot
177 union { intptr_t p; double d; } value;
178 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
179 value.d = ((ConstantDoubleValue *)sv)->value();
180 return new StackValue(value.p);
181 } else if (sv->is_constant_long()) {
182 // Constant long in a single stack slot
183 union { intptr_t p; jlong jl; } value;
184 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
185 value.jl = ((ConstantLongValue *)sv)->value();
186 return new StackValue(value.p);
187 #endif
188 } else if (sv->is_object()) { // Scalar replaced object in compiled frame
189 Handle ov = ((ObjectValue *)sv)->value();
190 return new StackValue(ov, (ov.is_null()) ? 1 : 0);
191 }
192
193 // Unknown ScopeValue type
194 ShouldNotReachHere();
195 return new StackValue((intptr_t) 0); // dummy
196 }
197
198
199 BasicLock* StackValue::resolve_monitor_lock(const frame* fr, Location location) {
200 assert(location.is_stack(), "for now we only look at the stack");
201 int word_offset = location.stack_offset() / wordSize;
202 // (stack picture)
203 // high: [ ] word_offset + 1
204 // low [ ] word_offset
205 //
206 // sp-> [ ] 0
207 // the word_offset is the distance from the stack pointer to the lowest address
208 // The frame's original stack pointer, before any extension by its callee
209 // (due to Compiler1 linkage on SPARC), must be used.
210 return (BasicLock*) (fr->unextended_sp() + word_offset);
211 }
212
213
214 #ifndef PRODUCT
215
216 void StackValue::print_on(outputStream* st) const {
217 switch(_type) {
218 case T_INT:
219 st->print("%d (int) %f (float) %x (hex)", *(int *)&_integer_value, *(float *)&_integer_value, *(int *)&_integer_value);
220 break;
221
222 case T_OBJECT:
223 _handle_value()->print_value_on(st);
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