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