1 /*
2 * Copyright (c) 1997, 2026, 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 "code/debugInfo.hpp"
26 #include "oops/access.hpp"
27 #include "oops/compressedOops.inline.hpp"
28 #include "oops/oop.hpp"
29 #include "runtime/frame.inline.hpp"
30 #include "runtime/globals.hpp"
31 #include "runtime/handles.inline.hpp"
32 #include "runtime/stackValue.hpp"
33 #if INCLUDE_SHENANDOAHGC
34 #include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
35 #endif
36
37 class RegisterMap;
38 class SmallRegisterMap;
39
40
41 static oop oop_from_oop_location(stackChunkOop chunk, void* addr) {
42 if (addr == nullptr) {
43 return nullptr;
44 }
45
46 if (UseCompressedOops) {
47 // When compressed oops is enabled, an oop location may
48 // contain narrow oop values - we deal with that here
49
50 if (chunk != nullptr && chunk->has_bitmap()) {
51 // Transformed stack chunk with narrow oops
52 return chunk->load_oop((narrowOop*)addr);
53 }
54
55 #ifdef _LP64
56 if (CompressedOops::is_base(*(void**)addr)) {
57 // Compiled code may produce decoded oop = narrow_oop_base
58 // when a narrow oop implicit null check is used.
59 // The narrow_oop_base could be null or be the address
60 // of the page below heap. Use null value for both cases.
61 return nullptr;
62 }
63 #endif
64 }
65
66 if (chunk != nullptr) {
67 // Load oop from chunk
68 return chunk->load_oop((oop*)addr);
69 }
70
71 // Load oop from stack
72 oop val = *(oop*)addr;
73
74 #if INCLUDE_SHENANDOAHGC
75 if (UseShenandoahGC) {
76 // Pass the value through the barrier to avoid capturing bad oops as
77 // stack values. Note: do not heal the location, to avoid accidentally
78 // corrupting the stack. Stack watermark barriers are supposed to handle
79 // the healing.
80 val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
81 }
82 #endif
83
84 return val;
85 }
86
87 static oop oop_from_narrowOop_location(stackChunkOop chunk, void* addr, bool is_register) {
88 assert(UseCompressedOops, "Narrow oops should not exist");
89 assert(addr != nullptr, "Not expecting null address");
90 narrowOop* narrow_addr;
91 if (is_register) {
92 // The callee has no clue whether the register holds an int,
93 // long or is unused. He always saves a long. Here we know
94 // a long was saved, but we only want an int back. Narrow the
95 // saved long to the int that the JVM wants. We can't just
96 // use narrow_oop_cast directly, because we don't know what
97 // the high bits of the value might be.
98 narrow_addr = ((narrowOop*)addr) BIG_ENDIAN_ONLY(+ 1);
99 } else {
100 narrow_addr = (narrowOop*)addr;
101 }
102
103 if (chunk != nullptr) {
104 // Load oop from chunk
105 return chunk->load_oop(narrow_addr);
106 }
107
108 // Load oop from stack
109 oop val = CompressedOops::decode(*narrow_addr);
110
111 #if INCLUDE_SHENANDOAHGC
112 if (UseShenandoahGC) {
113 // Pass the value through the barrier to avoid capturing bad oops as
114 // stack values. Note: do not heal the location, to avoid accidentally
115 // corrupting the stack. Stack watermark barriers are supposed to handle
116 // the healing.
117 val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
118 }
119 #endif
120
121 return val;
122 }
123
124 StackValue* StackValue::create_stack_value_from_oop_location(stackChunkOop chunk, void* addr) {
125 oop val = oop_from_oop_location(chunk, addr);
126 assert(oopDesc::is_oop_or_null(val), "bad oop found at " INTPTR_FORMAT " in_cont: %d compressed: %d",
127 p2i(addr), chunk != nullptr, chunk != nullptr && chunk->has_bitmap() && UseCompressedOops);
128 Handle h(Thread::current(), val); // Wrap a handle around the oop
129 return new StackValue(h);
130 }
131
132 StackValue* StackValue::create_stack_value_from_narrowOop_location(stackChunkOop chunk, void* addr, bool is_register) {
133 oop val = oop_from_narrowOop_location(chunk, addr, is_register);
134 assert(oopDesc::is_oop_or_null(val), "bad oop found at " INTPTR_FORMAT " in_cont: %d compressed: %d",
135 p2i(addr), chunk != nullptr, chunk != nullptr && chunk->has_bitmap() && UseCompressedOops);
136 Handle h(Thread::current(), val); // Wrap a handle around the oop
137 return new StackValue(h);
138 }
139
140 template StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv);
141 template StackValue* StackValue::create_stack_value(const frame* fr, const SmallRegisterMapNoArgs* reg_map, ScopeValue* sv);
142
143 template<typename RegisterMapT>
144 StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMapT* reg_map, ScopeValue* sv) {
145 address value_addr = stack_value_address(fr, reg_map, sv);
146 stackChunkOop chunk = reg_map->stack_chunk()();
147 if (sv->is_location()) {
148 // Stack or register value
149 Location loc = ((LocationValue *)sv)->location();
150
151 // Then package it right depending on type
152 // Note: the transfer of the data is thru a union that contains
153 // an intptr_t. This is because an interpreter stack slot is
154 // really an intptr_t. The use of a union containing an intptr_t
155 // ensures that on a 64 bit platform we have proper alignment
156 // and that we store the value where the interpreter will expect
157 // to find it (i.e. proper endian). Similarly on a 32bit platform
158 // using the intptr_t ensures that when a value is larger than
159 // a stack slot (jlong/jdouble) that we capture the proper part
160 // of the value for the stack slot in question.
161 //
162 switch( loc.type() ) {
163 case Location::float_in_dbl: { // Holds a float in a double register?
164 // The callee has no clue whether the register holds a float,
165 // double or is unused. He always saves a double. Here we know
166 // a double was saved, but we only want a float back. Narrow the
167 // saved double to the float that the JVM wants.
168 assert( loc.is_register(), "floats always saved to stack in 1 word" );
169 union { intptr_t p; jfloat jf; } value;
170 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
171 value.jf = (jfloat) *(jdouble*) value_addr;
172 return new StackValue(value.p); // 64-bit high half is stack junk
173 }
174 case Location::int_in_long: { // Holds an int in a long register?
175 // The callee has no clue whether the register holds an int,
176 // long or is unused. He always saves a long. Here we know
177 // a long was saved, but we only want an int back. Narrow the
178 // saved long to the int that the JVM wants.
179 assert( loc.is_register(), "ints always saved to stack in 1 word" );
180 union { intptr_t p; jint ji;} value;
181 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
182 value.ji = (jint) *(jlong*) value_addr;
183 return new StackValue(value.p); // 64-bit high half is stack junk
184 }
185 #ifdef _LP64
186 case Location::dbl:
187 // Double value in an aligned adjacent pair
188 return new StackValue(*(intptr_t*)value_addr);
189 case Location::lng:
190 // Long value in an aligned adjacent pair
191 return new StackValue(*(intptr_t*)value_addr);
192 case Location::narrowoop:
193 return create_stack_value_from_narrowOop_location(reg_map->stack_chunk()(), (void*)value_addr, loc.is_register());
194 #endif
195 case Location::oop:
196 return create_stack_value_from_oop_location(reg_map->stack_chunk()(), (void*)value_addr);
197 case Location::addr: {
198 loc.print_on(tty);
199 ShouldNotReachHere(); // both C1 and C2 now inline jsrs
200 }
201 case Location::normal: {
202 // Just copy all other bits straight through
203 union { intptr_t p; jint ji;} value;
204 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
205 value.ji = *(jint*)value_addr;
206 return new StackValue(value.p);
207 }
208 case Location::invalid: {
209 return new StackValue();
210 }
211 case Location::vector: {
212 loc.print_on(tty);
213 ShouldNotReachHere(); // should be handled by VectorSupport::allocate_vector()
214 }
215 default:
216 loc.print_on(tty);
217 ShouldNotReachHere();
218 }
219
220 } else if (sv->is_constant_int()) {
221 // Constant int: treat same as register int.
222 union { intptr_t p; jint ji;} value;
223 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
224 value.ji = (jint)((ConstantIntValue*)sv)->value();
225 return new StackValue(value.p);
226 } else if (sv->is_constant_oop()) {
227 // constant oop
228 return new StackValue(sv->as_ConstantOopReadValue()->value());
229 #ifdef _LP64
230 } else if (sv->is_constant_double()) {
231 // Constant double in a single stack slot
232 union { intptr_t p; double d; } value;
233 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
234 value.d = ((ConstantDoubleValue *)sv)->value();
235 return new StackValue(value.p);
236 } else if (sv->is_constant_long()) {
237 // Constant long in a single stack slot
238 union { intptr_t p; jlong jl; } value;
239 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
240 value.jl = ((ConstantLongValue *)sv)->value();
241 return new StackValue(value.p);
242 #endif
243 } else if (sv->is_object()) { // Scalar replaced object in compiled frame
244 ObjectValue* ov = (ObjectValue *)sv;
245 Handle hdl = ov->value();
246 bool scalar_replaced = hdl.is_null() && ov->is_scalar_replaced();
247 if (ov->has_properties()) {
248 Klass* k = java_lang_Class::as_Klass(ov->klass()->as_ConstantOopReadValue()->value()());
249 if (!k->is_array_klass()) {
250 // Don't treat inline type as scalar replaced if it is null
251 jint null_marker = StackValue::create_stack_value(fr, reg_map, ov->properties())->get_jint();
252 scalar_replaced &= (null_marker != 0);
253 }
254 }
255 return new StackValue(hdl, scalar_replaced ? 1 : 0);
256 } else if (sv->is_marker()) {
257 // Should never need to directly construct a marker.
258 ShouldNotReachHere();
259 }
260 // Unknown ScopeValue type
261 ShouldNotReachHere();
262 return new StackValue((intptr_t) 0); // dummy
263 }
264
265 template address StackValue::stack_value_address(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv);
266 template address StackValue::stack_value_address(const frame* fr, const SmallRegisterMapNoArgs* reg_map, ScopeValue* sv);
267
268 template<typename RegisterMapT>
269 address StackValue::stack_value_address(const frame* fr, const RegisterMapT* reg_map, ScopeValue* sv) {
270 if (!sv->is_location()) {
271 return nullptr;
272 }
273 Location loc = ((LocationValue *)sv)->location();
274 if (loc.type() == Location::invalid) {
275 return nullptr;
276 }
277
278 if (!reg_map->in_cont()) {
279 address value_addr = loc.is_register()
280 // Value was in a callee-save register
281 ? reg_map->location(VMRegImpl::as_VMReg(loc.register_number()), fr->sp())
282 // Else value was directly saved on the stack. The frame's original stack pointer,
283 // before any extension by its callee (due to Compiler1 linkage on SPARC), must be used.
284 : ((address)fr->unextended_sp()) + loc.stack_offset();
285
286 assert(value_addr == nullptr || reg_map->thread() == nullptr || reg_map->thread()->is_in_usable_stack(value_addr), INTPTR_FORMAT, p2i(value_addr));
287 return value_addr;
288 }
289
290 address value_addr = loc.is_register()
291 ? reg_map->as_RegisterMap()->stack_chunk()->reg_to_location(*fr, reg_map->as_RegisterMap(), VMRegImpl::as_VMReg(loc.register_number()))
292 : reg_map->as_RegisterMap()->stack_chunk()->usp_offset_to_location(*fr, loc.stack_offset());
293
294 assert(value_addr == nullptr || Continuation::is_in_usable_stack(value_addr, reg_map->as_RegisterMap()) || (reg_map->thread() != nullptr && reg_map->thread()->is_in_usable_stack(value_addr)), INTPTR_FORMAT, p2i(value_addr));
295 return value_addr;
296 }
297
298 BasicLock* StackValue::resolve_monitor_lock(const frame& fr, Location location) {
299 assert(location.is_stack(), "for now we only look at the stack");
300 int word_offset = location.stack_offset() / wordSize;
301 // (stack picture)
302 // high: [ ] word_offset + 1
303 // low [ ] word_offset
304 //
305 // sp-> [ ] 0
306 // the word_offset is the distance from the stack pointer to the lowest address
307 // The frame's original stack pointer, before any extension by its callee
308 // (due to Compiler1 linkage on SPARC), must be used.
309 return (BasicLock*) (fr.unextended_sp() + word_offset);
310 }
311
312
313 #ifndef PRODUCT
314
315 void StackValue::print_on(outputStream* st) const {
316 switch(_type) {
317 case T_INT:
318 st->print("%d (int) %f (float) %x (hex)", *(int *)&_integer_value, *(float *)&_integer_value, *(int *)&_integer_value);
319 break;
320
321 case T_OBJECT:
322 if (_handle_value() != nullptr) {
323 _handle_value()->print_value_on(st);
324 } else {
325 st->print("null");
326 }
327 st->print(" <" INTPTR_FORMAT ">", p2i(_handle_value()));
328 break;
329
330 case T_CONFLICT:
331 st->print("conflict");
332 break;
333
334 default:
335 ShouldNotReachHere();
336 }
337 }
338
339 #endif