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
36 StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv) {
37 if (sv->is_location()) {
38 // Stack or register value
39 Location loc = ((LocationValue *)sv)->location();
40
41 #ifdef SPARC
42 // %%%%% Callee-save floats will NOT be working on a Sparc until we
43 // handle the case of a 2 floats in a single double register.
44 assert( !(loc.is_register() && loc.type() == Location::float_in_dbl), "Sparc does not handle callee-save floats yet" );
45 #endif // SPARC
46
47 // First find address of value
48
49 address value_addr = loc.is_register()
50 // Value was in a callee-save register
51 ? reg_map->location(VMRegImpl::as_VMReg(loc.register_number()))
52 // Else value was directly saved on the stack. The frame's original stack pointer,
53 // before any extension by its callee (due to Compiler1 linkage on SPARC), must be used.
54 : ((address)fr->unextended_sp()) + loc.stack_offset();
55
56 // Then package it right depending on type
57 // Note: the transfer of the data is thru a union that contains
58 // an intptr_t. This is because an interpreter stack slot is
59 // really an intptr_t. The use of a union containing an intptr_t
60 // ensures that on a 64 bit platform we have proper alignment
61 // and that we store the value where the interpreter will expect
62 // to find it (i.e. proper endian). Similarly on a 32bit platform
63 // using the intptr_t ensures that when a value is larger than
64 // a stack slot (jlong/jdouble) that we capture the proper part
65 // of the value for the stack slot in question.
66 //
67 switch( loc.type() ) {
68 case Location::float_in_dbl: { // Holds a float in a double register?
69 // The callee has no clue whether the register holds a float,
70 // double or is unused. He always saves a double. Here we know
71 // a double was saved, but we only want a float back. Narrow the
72 // saved double to the float that the JVM wants.
73 assert( loc.is_register(), "floats always saved to stack in 1 word" );
74 union { intptr_t p; jfloat jf; } value;
75 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
76 value.jf = (jfloat) *(jdouble*) value_addr;
77 return new StackValue(value.p); // 64-bit high half is stack junk
78 }
79 case Location::int_in_long: { // Holds an int in a long register?
80 // The callee has no clue whether the register holds an int,
81 // long or is unused. He always saves a long. Here we know
82 // a long was saved, but we only want an int back. Narrow the
83 // saved long to the int that the JVM wants.
84 assert( loc.is_register(), "ints always saved to stack in 1 word" );
85 union { intptr_t p; jint ji;} value;
86 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
87 value.ji = (jint) *(jlong*) value_addr;
88 return new StackValue(value.p); // 64-bit high half is stack junk
89 }
90 #ifdef _LP64
91 case Location::dbl:
92 // Double value in an aligned adjacent pair
93 return new StackValue(*(intptr_t*)value_addr);
94 case Location::lng:
95 // Long value in an aligned adjacent pair
96 return new StackValue(*(intptr_t*)value_addr);
97 case Location::narrowoop: {
98 union { intptr_t p; narrowOop noop;} value;
99 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
100 if (loc.is_register()) {
101 // The callee has no clue whether the register holds an int,
102 // long or is unused. He always saves a long. Here we know
103 // a long was saved, but we only want an int back. Narrow the
104 // saved long to the int that the JVM wants.
105 value.noop = (narrowOop) *(julong*) value_addr;
106 } else {
107 value.noop = *(narrowOop*) value_addr;
108 }
109 // Decode narrowoop and wrap a handle around the oop
110 Handle h(Thread::current(), CompressedOops::decode(value.noop));
111 return new StackValue(h);
112 }
113 #endif
114 case Location::oop: {
115 oop val = *(oop *)value_addr;
116 #ifdef _LP64
117 if (Universe::is_narrow_oop_base(val)) {
118 // Compiled code may produce decoded oop = narrow_oop_base
119 // when a narrow oop implicit null check is used.
120 // The narrow_oop_base could be NULL or be the address
121 // of the page below heap. Use NULL value for both cases.
122 val = (oop)NULL;
123 }
124 #endif
125 #if INCLUDE_ZGC
126 // Deoptimization must make sure all oop have passed load barrier
127 if (UseZGC) {
128 val = ZBarrier::load_barrier_on_oop_field_preloaded((oop*)value_addr, val);
129 }
130 #endif
131
132 Handle h(Thread::current(), val); // Wrap a handle around the oop
133 return new StackValue(h);
134 }
135 case Location::addr: {
136 ShouldNotReachHere(); // both C1 and C2 now inline jsrs
137 }
138 case Location::normal: {
139 // Just copy all other bits straight through
140 union { intptr_t p; jint ji;} value;
141 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
142 value.ji = *(jint*)value_addr;
143 return new StackValue(value.p);
144 }
145 case Location::invalid:
146 return new StackValue();
147 default:
148 ShouldNotReachHere();
149 }
150
151 } else if (sv->is_constant_int()) {
152 // Constant int: treat same as register int.
153 union { intptr_t p; jint ji;} value;
154 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
155 value.ji = (jint)((ConstantIntValue*)sv)->value();
156 return new StackValue(value.p);
157 } else if (sv->is_constant_oop()) {
158 // constant oop
159 return new StackValue(sv->as_ConstantOopReadValue()->value());
160 #ifdef _LP64
161 } else if (sv->is_constant_double()) {
162 // Constant double in a single stack slot
163 union { intptr_t p; double d; } value;
164 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
165 value.d = ((ConstantDoubleValue *)sv)->value();
166 return new StackValue(value.p);
167 } else if (sv->is_constant_long()) {
168 // Constant long in a single stack slot
169 union { intptr_t p; jlong jl; } value;
170 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
171 value.jl = ((ConstantLongValue *)sv)->value();
172 return new StackValue(value.p);
173 #endif
174 } else if (sv->is_object()) { // Scalar replaced object in compiled frame
175 Handle ov = ((ObjectValue *)sv)->value();
176 return new StackValue(ov, (ov.is_null()) ? 1 : 0);
177 }
178
179 // Unknown ScopeValue type
180 ShouldNotReachHere();
181 return new StackValue((intptr_t) 0); // dummy
182 }
183
184
185 BasicLock* StackValue::resolve_monitor_lock(const frame* fr, Location location) {
186 assert(location.is_stack(), "for now we only look at the stack");
187 int word_offset = location.stack_offset() / wordSize;
188 // (stack picture)
189 // high: [ ] word_offset + 1
190 // low [ ] word_offset
191 //
192 // sp-> [ ] 0
193 // the word_offset is the distance from the stack pointer to the lowest address
194 // The frame's original stack pointer, before any extension by its callee
195 // (due to Compiler1 linkage on SPARC), must be used.
196 return (BasicLock*) (fr->unextended_sp() + word_offset);
197 }
198
199
200 #ifndef PRODUCT
201
202 void StackValue::print_on(outputStream* st) const {
203 switch(_type) {
204 case T_INT:
205 st->print("%d (int) %f (float) %x (hex)", *(int *)&_integer_value, *(float *)&_integer_value, *(int *)&_integer_value);
206 break;
207
208 case T_OBJECT:
209 _handle_value()->print_value_on(st);
210 st->print(" <" INTPTR_FORMAT ">", p2i((address)_handle_value()));
211 break;
212
213 case T_CONFLICT:
214 st->print("conflict");
215 break;
216
217 default:
218 ShouldNotReachHere();
219 }
220 }
221
222 #endif