1 /*
2 * Copyright (c) 1997, 2025, 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 template StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv);
41 template StackValue* StackValue::create_stack_value(const frame* fr, const SmallRegisterMap* reg_map, ScopeValue* sv);
42
43 template<typename RegisterMapT>
44 StackValue* StackValue::create_stack_value(const frame* fr, const RegisterMapT* reg_map, ScopeValue* sv) {
45 return create_stack_value(sv, stack_value_address(fr, reg_map, sv), reg_map);
46 }
47
48 static oop oop_from_oop_location(stackChunkOop chunk, void* addr) {
49 if (addr == nullptr) {
50 return nullptr;
51 }
52
53 if (UseCompressedOops) {
54 // When compressed oops is enabled, an oop location may
55 // contain narrow oop values - we deal with that here
56
57 if (chunk != nullptr && chunk->has_bitmap()) {
58 // Transformed stack chunk with narrow oops
59 return chunk->load_oop((narrowOop*)addr);
60 }
61
62 #ifdef _LP64
63 if (CompressedOops::is_base(*(void**)addr)) {
64 // Compiled code may produce decoded oop = narrow_oop_base
65 // when a narrow oop implicit null check is used.
66 // The narrow_oop_base could be null or be the address
67 // of the page below heap. Use null value for both cases.
68 return nullptr;
69 }
70 #endif
71 }
72
73 if (chunk != nullptr) {
74 // Load oop from chunk
75 return chunk->load_oop((oop*)addr);
76 }
77
78 // Load oop from stack
79 oop val = *(oop*)addr;
80
81 #if INCLUDE_SHENANDOAHGC
82 if (UseShenandoahGC) {
83 // Pass the value through the barrier to avoid capturing bad oops as
84 // stack values. Note: do not heal the location, to avoid accidentally
85 // corrupting the stack. Stack watermark barriers are supposed to handle
86 // the healing.
87 val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
88 }
89 #endif
90
91 return val;
92 }
93
94 static oop oop_from_narrowOop_location(stackChunkOop chunk, void* addr, bool is_register) {
95 assert(UseCompressedOops, "Narrow oops should not exist");
96 assert(addr != nullptr, "Not expecting null address");
97 narrowOop* narrow_addr;
98 if (is_register) {
99 // The callee has no clue whether the register holds an int,
100 // long or is unused. He always saves a long. Here we know
101 // a long was saved, but we only want an int back. Narrow the
102 // saved long to the int that the JVM wants. We can't just
103 // use narrow_oop_cast directly, because we don't know what
104 // the high bits of the value might be.
105 narrow_addr = ((narrowOop*)addr) BIG_ENDIAN_ONLY(+ 1);
106 } else {
107 narrow_addr = (narrowOop*)addr;
108 }
109
110 if (chunk != nullptr) {
111 // Load oop from chunk
112 return chunk->load_oop(narrow_addr);
113 }
114
115 // Load oop from stack
116 oop val = CompressedOops::decode(*narrow_addr);
117
118 #if INCLUDE_SHENANDOAHGC
119 if (UseShenandoahGC) {
120 // Pass the value through the barrier to avoid capturing bad oops as
121 // stack values. Note: do not heal the location, to avoid accidentally
122 // corrupting the stack. Stack watermark barriers are supposed to handle
123 // the healing.
124 val = ShenandoahBarrierSet::barrier_set()->load_reference_barrier(val);
125 }
126 #endif
127
128 return val;
129 }
130
131 StackValue* StackValue::create_stack_value_from_oop_location(stackChunkOop chunk, void* addr) {
132 oop val = oop_from_oop_location(chunk, addr);
133 assert(oopDesc::is_oop_or_null(val), "bad oop found at " INTPTR_FORMAT " in_cont: %d compressed: %d",
134 p2i(addr), chunk != nullptr, chunk != nullptr && chunk->has_bitmap() && UseCompressedOops);
135 Handle h(Thread::current(), val); // Wrap a handle around the oop
136 return new StackValue(h);
137 }
138
139 StackValue* StackValue::create_stack_value_from_narrowOop_location(stackChunkOop chunk, void* addr, bool is_register) {
140 oop val = oop_from_narrowOop_location(chunk, addr, is_register);
141 assert(oopDesc::is_oop_or_null(val), "bad oop found at " INTPTR_FORMAT " in_cont: %d compressed: %d",
142 p2i(addr), chunk != nullptr, chunk != nullptr && chunk->has_bitmap() && UseCompressedOops);
143 Handle h(Thread::current(), val); // Wrap a handle around the oop
144 return new StackValue(h);
145 }
146
147 template<typename RegisterMapT>
148 StackValue* StackValue::create_stack_value(ScopeValue* sv, address value_addr, const RegisterMapT* reg_map) {
149 stackChunkOop chunk = reg_map->stack_chunk()();
150 if (sv->is_location()) {
151 // Stack or register value
152 Location loc = ((LocationValue *)sv)->location();
153
154 // Then package it right depending on type
155 // Note: the transfer of the data is thru a union that contains
156 // an intptr_t. This is because an interpreter stack slot is
157 // really an intptr_t. The use of a union containing an intptr_t
158 // ensures that on a 64 bit platform we have proper alignment
159 // and that we store the value where the interpreter will expect
160 // to find it (i.e. proper endian). Similarly on a 32bit platform
161 // using the intptr_t ensures that when a value is larger than
162 // a stack slot (jlong/jdouble) that we capture the proper part
163 // of the value for the stack slot in question.
164 //
165 switch( loc.type() ) {
166 case Location::float_in_dbl: { // Holds a float in a double register?
167 // The callee has no clue whether the register holds a float,
168 // double or is unused. He always saves a double. Here we know
169 // a double was saved, but we only want a float back. Narrow the
170 // saved double to the float that the JVM wants.
171 assert( loc.is_register(), "floats always saved to stack in 1 word" );
172 union { intptr_t p; jfloat jf; } value;
173 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
174 value.jf = (jfloat) *(jdouble*) value_addr;
175 return new StackValue(value.p); // 64-bit high half is stack junk
176 }
177 case Location::int_in_long: { // Holds an int in a long register?
178 // The callee has no clue whether the register holds an int,
179 // long or is unused. He always saves a long. Here we know
180 // a long was saved, but we only want an int back. Narrow the
181 // saved long to the int that the JVM wants.
182 assert( loc.is_register(), "ints always saved to stack in 1 word" );
183 union { intptr_t p; jint ji;} value;
184 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
185 value.ji = (jint) *(jlong*) value_addr;
186 return new StackValue(value.p); // 64-bit high half is stack junk
187 }
188 #ifdef _LP64
189 case Location::dbl:
190 // Double value in an aligned adjacent pair
191 return new StackValue(*(intptr_t*)value_addr);
192 case Location::lng:
193 // Long value in an aligned adjacent pair
194 return new StackValue(*(intptr_t*)value_addr);
195 case Location::narrowoop:
196 return create_stack_value_from_narrowOop_location(reg_map->stack_chunk()(), (void*)value_addr, loc.is_register());
197 #endif
198 case Location::oop:
199 return create_stack_value_from_oop_location(reg_map->stack_chunk()(), (void*)value_addr);
200 case Location::addr: {
201 loc.print_on(tty);
202 ShouldNotReachHere(); // both C1 and C2 now inline jsrs
203 }
204 case Location::normal: {
205 // Just copy all other bits straight through
206 union { intptr_t p; jint ji;} value;
207 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
208 value.ji = *(jint*)value_addr;
209 return new StackValue(value.p);
210 }
211 case Location::invalid: {
212 return new StackValue();
213 }
214 case Location::vector: {
215 loc.print_on(tty);
216 ShouldNotReachHere(); // should be handled by VectorSupport::allocate_vector()
217 }
218 default:
219 loc.print_on(tty);
220 ShouldNotReachHere();
221 }
222
223 } else if (sv->is_constant_int()) {
224 // Constant int: treat same as register int.
225 union { intptr_t p; jint ji;} value;
226 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
227 value.ji = (jint)((ConstantIntValue*)sv)->value();
228 return new StackValue(value.p);
229 } else if (sv->is_constant_oop()) {
230 // constant oop
231 return new StackValue(sv->as_ConstantOopReadValue()->value());
232 #ifdef _LP64
233 } else if (sv->is_constant_double()) {
234 // Constant double in a single stack slot
235 union { intptr_t p; double d; } value;
236 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
237 value.d = ((ConstantDoubleValue *)sv)->value();
238 return new StackValue(value.p);
239 } else if (sv->is_constant_long()) {
240 // Constant long in a single stack slot
241 union { intptr_t p; jlong jl; } value;
242 value.p = (intptr_t) CONST64(0xDEADDEAFDEADDEAF);
243 value.jl = ((ConstantLongValue *)sv)->value();
244 return new StackValue(value.p);
245 #endif
246 } else if (sv->is_object()) { // Scalar replaced object in compiled frame
247 ObjectValue* ov = (ObjectValue *)sv;
248 Handle hdl = ov->value();
249 return new StackValue(hdl, hdl.is_null() && ov->is_scalar_replaced() ? 1 : 0);
250 } else if (sv->is_marker()) {
251 // Should never need to directly construct a marker.
252 ShouldNotReachHere();
253 }
254 // Unknown ScopeValue type
255 ShouldNotReachHere();
256 return new StackValue((intptr_t) 0); // dummy
257 }
258
259 template address StackValue::stack_value_address(const frame* fr, const RegisterMap* reg_map, ScopeValue* sv);
260 template address StackValue::stack_value_address(const frame* fr, const SmallRegisterMap* reg_map, ScopeValue* sv);
261
262 template<typename RegisterMapT>
263 address StackValue::stack_value_address(const frame* fr, const RegisterMapT* reg_map, ScopeValue* sv) {
264 if (!sv->is_location()) {
265 return nullptr;
266 }
267 Location loc = ((LocationValue *)sv)->location();
268 if (loc.type() == Location::invalid) {
269 return nullptr;
270 }
271
272 if (!reg_map->in_cont()) {
273 address value_addr = loc.is_register()
274 // Value was in a callee-save register
275 ? reg_map->location(VMRegImpl::as_VMReg(loc.register_number()), fr->sp())
276 // Else value was directly saved on the stack. The frame's original stack pointer,
277 // before any extension by its callee (due to Compiler1 linkage on SPARC), must be used.
278 : ((address)fr->unextended_sp()) + loc.stack_offset();
279
280 assert(value_addr == nullptr || reg_map->thread() == nullptr || reg_map->thread()->is_in_usable_stack(value_addr), INTPTR_FORMAT, p2i(value_addr));
281 return value_addr;
282 }
283
284 address value_addr = loc.is_register()
285 ? reg_map->as_RegisterMap()->stack_chunk()->reg_to_location(*fr, reg_map->as_RegisterMap(), VMRegImpl::as_VMReg(loc.register_number()))
286 : reg_map->as_RegisterMap()->stack_chunk()->usp_offset_to_location(*fr, loc.stack_offset());
287
288 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));
289 return value_addr;
290 }
291
292 BasicLock* StackValue::resolve_monitor_lock(const frame& fr, Location location) {
293 assert(location.is_stack(), "for now we only look at the stack");
294 int word_offset = location.stack_offset() / wordSize;
295 // (stack picture)
296 // high: [ ] word_offset + 1
297 // low [ ] word_offset
298 //
299 // sp-> [ ] 0
300 // the word_offset is the distance from the stack pointer to the lowest address
301 // The frame's original stack pointer, before any extension by its callee
302 // (due to Compiler1 linkage on SPARC), must be used.
303 return (BasicLock*) (fr.unextended_sp() + word_offset);
304 }
305
306
307 #ifndef PRODUCT
308
309 void StackValue::print_on(outputStream* st) const {
310 switch(_type) {
311 case T_INT:
312 st->print("%d (int) %f (float) %x (hex)", *(int *)&_integer_value, *(float *)&_integer_value, *(int *)&_integer_value);
313 break;
314
315 case T_OBJECT:
316 if (_handle_value() != nullptr) {
317 _handle_value()->print_value_on(st);
318 } else {
319 st->print("null");
320 }
321 st->print(" <" INTPTR_FORMAT ">", p2i(_handle_value()));
322 break;
323
324 case T_CONFLICT:
325 st->print("conflict");
326 break;
327
328 default:
329 ShouldNotReachHere();
330 }
331 }
332
333 #endif