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