1 /*
2 * Copyright (c) 1999, 2024, 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.
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23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_MacroAssembler.hpp"
27 #include "c1/c1_Runtime1.hpp"
28 #include "compiler/compilerDefinitions.inline.hpp"
29 #include "gc/shared/barrierSet.hpp"
30 #include "gc/shared/barrierSetAssembler.hpp"
31 #include "gc/shared/collectedHeap.hpp"
32 #include "gc/shared/tlab_globals.hpp"
33 #include "interpreter/interpreter.hpp"
34 #include "oops/arrayOop.hpp"
35 #include "oops/markWord.hpp"
36 #include "runtime/basicLock.hpp"
37 #include "runtime/globals.hpp"
38 #include "runtime/os.hpp"
39 #include "runtime/sharedRuntime.hpp"
40 #include "runtime/stubRoutines.hpp"
41 #include "utilities/globalDefinitions.hpp"
42
43 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register tmp, Label& slow_case) {
44 const int aligned_mask = BytesPerWord -1;
45 const int hdr_offset = oopDesc::mark_offset_in_bytes();
46 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
47 assert_different_registers(hdr, obj, disp_hdr, tmp);
48 int null_check_offset = -1;
49
50 verify_oop(obj);
51
52 // save object being locked into the BasicObjectLock
53 movptr(Address(disp_hdr, BasicObjectLock::obj_offset()), obj);
54
55 null_check_offset = offset();
56
57 if (DiagnoseSyncOnValueBasedClasses != 0) {
58 load_klass(hdr, obj, rscratch1);
59 movl(hdr, Address(hdr, Klass::access_flags_offset()));
60 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
61 jcc(Assembler::notZero, slow_case);
62 }
63
64 if (LockingMode == LM_LIGHTWEIGHT) {
65 #ifdef _LP64
66 const Register thread = r15_thread;
67 #else
68 const Register thread = disp_hdr;
69 get_thread(thread);
70 #endif
71 lightweight_lock(obj, hdr, thread, tmp, slow_case);
72 } else if (LockingMode == LM_LEGACY) {
73 Label done;
74 // Load object header
75 movptr(hdr, Address(obj, hdr_offset));
76 // and mark it as unlocked
77 orptr(hdr, markWord::unlocked_value);
78 // save unlocked object header into the displaced header location on the stack
79 movptr(Address(disp_hdr, 0), hdr);
80 // test if object header is still the same (i.e. unlocked), and if so, store the
81 // displaced header address in the object header - if it is not the same, get the
82 // object header instead
83 MacroAssembler::lock(); // must be immediately before cmpxchg!
84 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
85 // if the object header was the same, we're done
86 jcc(Assembler::equal, done);
87 // if the object header was not the same, it is now in the hdr register
88 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
89 //
90 // 1) (hdr & aligned_mask) == 0
91 // 2) rsp <= hdr
92 // 3) hdr <= rsp + page_size
93 //
94 // these 3 tests can be done by evaluating the following expression:
95 //
96 // (hdr - rsp) & (aligned_mask - page_size)
97 //
98 // assuming both the stack pointer and page_size have their least
99 // significant 2 bits cleared and page_size is a power of 2
100 subptr(hdr, rsp);
101 andptr(hdr, aligned_mask - (int)os::vm_page_size());
102 // for recursive locking, the result is zero => save it in the displaced header
103 // location (null in the displaced hdr location indicates recursive locking)
104 movptr(Address(disp_hdr, 0), hdr);
105 // otherwise we don't care about the result and handle locking via runtime call
106 jcc(Assembler::notZero, slow_case);
107 // done
108 bind(done);
109 }
110
111 inc_held_monitor_count();
112
113 return null_check_offset;
114 }
115
116 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
117 const int aligned_mask = BytesPerWord -1;
118 const int hdr_offset = oopDesc::mark_offset_in_bytes();
119 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
120 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
121 Label done;
122
123 if (LockingMode != LM_LIGHTWEIGHT) {
124 // load displaced header
125 movptr(hdr, Address(disp_hdr, 0));
126 // if the loaded hdr is null we had recursive locking
127 testptr(hdr, hdr);
128 // if we had recursive locking, we are done
129 jcc(Assembler::zero, done);
130 }
131
132 // load object
133 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
134 verify_oop(obj);
135
136 if (LockingMode == LM_LIGHTWEIGHT) {
137 #ifdef _LP64
138 lightweight_unlock(obj, disp_hdr, r15_thread, hdr, slow_case);
139 #else
140 // This relies on the implementation of lightweight_unlock being able to handle
141 // that the reg_rax and thread Register parameters may alias each other.
142 get_thread(disp_hdr);
143 lightweight_unlock(obj, disp_hdr, disp_hdr, hdr, slow_case);
144 #endif
145 } else if (LockingMode == LM_LEGACY) {
146 // test if object header is pointing to the displaced header, and if so, restore
147 // the displaced header in the object - if the object header is not pointing to
148 // the displaced header, get the object header instead
149 MacroAssembler::lock(); // must be immediately before cmpxchg!
150 cmpxchgptr(hdr, Address(obj, hdr_offset));
151 // if the object header was not pointing to the displaced header,
152 // we do unlocking via runtime call
153 jcc(Assembler::notEqual, slow_case);
154 // done
155 }
156 bind(done);
157 dec_held_monitor_count();
158 }
159
160
161 // Defines obj, preserves var_size_in_bytes
162 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
163 if (UseTLAB) {
164 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
165 } else {
166 jmp(slow_case);
167 }
168 }
169
170
171 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
172 assert_different_registers(obj, klass, len, t1, t2);
173 #ifdef _LP64
174 if (UseCompactObjectHeaders) {
175 movptr(t1, Address(klass, Klass::prototype_header_offset()));
176 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
177 } else if (UseCompressedClassPointers) { // Take care not to kill klass
178 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
179 movptr(t1, klass);
180 encode_klass_not_null(t1, rscratch1);
181 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
182 } else
183 #endif
184 {
185 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
186 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
187 }
188
189 if (len->is_valid()) {
190 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
191 }
192 #ifdef _LP64
193 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) {
194 xorptr(t1, t1);
195 store_klass_gap(obj, t1);
196 }
197 #endif
198 }
199
200
201 // preserves obj, destroys len_in_bytes
202 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
203 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
204 Label done;
205
206 // len_in_bytes is positive and ptr sized
207 subptr(len_in_bytes, hdr_size_in_bytes);
208 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
209 bind(done);
210 }
211
212
213 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
214 assert(obj == rax, "obj must be in rax, for cmpxchg");
215 assert_different_registers(obj, t1, t2); // XXX really?
216 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
217
218 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
219
220 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
221 }
222
223 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, bool is_tlab_allocated) {
224 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
225 "con_size_in_bytes is not multiple of alignment");
226 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
227 assert(!UseCompactObjectHeaders || hdr_size_in_bytes == 8, "check object headers size");
228
229 initialize_header(obj, klass, noreg, t1, t2);
230
231 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
232 // clear rest of allocated space
233 const Register t1_zero = t1;
234 const Register index = t2;
235 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
236 if (var_size_in_bytes != noreg) {
237 mov(index, var_size_in_bytes);
238 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
239 } else if (con_size_in_bytes <= threshold) {
240 // use explicit null stores
241 // code size = 2 + 3*n bytes (n = number of fields to clear)
242 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
243 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
244 movptr(Address(obj, i), t1_zero);
245 } else if (con_size_in_bytes > hdr_size_in_bytes) {
246 // use loop to null out the fields
247 // code size = 16 bytes for even n (n = number of fields to clear)
248 // initialize last object field first if odd number of fields
249 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
250 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
251 // initialize last object field if constant size is odd
252 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
253 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
254 // initialize remaining object fields: rdx is a multiple of 2
255 { Label loop;
256 bind(loop);
257 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
258 t1_zero);
259 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
260 t1_zero);)
261 decrement(index);
262 jcc(Assembler::notZero, loop);
263 }
264 }
265 }
266
267 if (CURRENT_ENV->dtrace_alloc_probes()) {
268 assert(obj == rax, "must be");
269 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
270 }
271
272 verify_oop(obj);
273 }
274
275 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int base_offset_in_bytes, Address::ScaleFactor f, Register klass, Label& slow_case) {
276 assert(obj == rax, "obj must be in rax, for cmpxchg");
277 assert_different_registers(obj, len, t1, t2, klass);
278
279 // determine alignment mask
280 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
281
282 // check for negative or excessive length
283 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length));
284 jcc(Assembler::above, slow_case);
285
286 const Register arr_size = t2; // okay to be the same
287 // align object end
288 movptr(arr_size, base_offset_in_bytes + MinObjAlignmentInBytesMask);
289 lea(arr_size, Address(arr_size, len, f));
290 andptr(arr_size, ~MinObjAlignmentInBytesMask);
291
292 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
293
294 initialize_header(obj, klass, len, t1, t2);
295
296 // Clear leading 4 bytes, if necessary.
297 // TODO: This could perhaps go into initialize_body() and also clear the leading 4 bytes
298 // for non-array objects, thereby replacing the klass-gap clearing code in initialize_header().
299 int base_offset = base_offset_in_bytes;
300 #ifdef _LP64
301 if (!is_aligned(base_offset, BytesPerWord)) {
302 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned");
303 movl(Address(obj, base_offset), 0);
304 base_offset += BytesPerInt;
305 }
306 #endif
307 assert(is_aligned(base_offset, BytesPerWord), "must be word aligned");
308
309 // clear rest of allocated space
310 const Register len_zero = len;
311 initialize_body(obj, arr_size, base_offset, len_zero);
312
313 if (CURRENT_ENV->dtrace_alloc_probes()) {
314 assert(obj == rax, "must be");
315 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
316 }
317
318 verify_oop(obj);
319 }
320
321
322
323 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
324 verify_oop(receiver);
325 // explicit null check not needed since load from [klass_offset] causes a trap
326 // check against inline cache. This is checked in Universe::genesis().
327 int start_offset = offset();
328
329 if (UseCompressedClassPointers) {
330 load_klass(rscratch1, receiver, rscratch2);
331 cmpptr(rscratch1, iCache);
332 } else {
333 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
334 }
335 // if icache check fails, then jump to runtime routine
336 // Note: RECEIVER must still contain the receiver!
337 jump_cc(Assembler::notEqual,
338 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
339 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
340 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
341 }
342
343
344 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
345 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
346 // Make sure there is enough stack space for this method's activation.
347 // Note that we do this before doing an enter(). This matches the
348 // ordering of C2's stack overflow check / rsp decrement and allows
349 // the SharedRuntime stack overflow handling to be consistent
350 // between the two compilers.
351 generate_stack_overflow_check(bang_size_in_bytes);
352
353 push(rbp);
354 if (PreserveFramePointer) {
355 mov(rbp, rsp);
356 }
357 #if !defined(_LP64) && defined(COMPILER2)
358 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) {
359 // c2 leaves fpu stack dirty. Clean it on entry
360 empty_FPU_stack();
361 }
362 #endif // !_LP64 && COMPILER2
363 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
364
365 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
366 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
367 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */);
368 }
369
370
371 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
372 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
373 pop(rbp);
374 }
375
376
377 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
378 if (breakAtEntry || VerifyFPU) {
379 // Verified Entry first instruction should be 5 bytes long for correct
380 // patching by patch_verified_entry().
381 //
382 // Breakpoint and VerifyFPU have one byte first instruction.
383 // Also first instruction will be one byte "push(rbp)" if stack banging
384 // code is not generated (see build_frame() above).
385 // For all these cases generate long instruction first.
386 fat_nop();
387 }
388 if (breakAtEntry) int3();
389 // build frame
390 IA32_ONLY( verify_FPU(0, "method_entry"); )
391 }
392
393 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
394 // rbp, + 0: link
395 // + 1: return address
396 // + 2: argument with offset 0
397 // + 3: argument with offset 1
398 // + 4: ...
399
400 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
401 }
402
403 #ifndef PRODUCT
404
405 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
406 if (!VerifyOops) return;
407 verify_oop_addr(Address(rsp, stack_offset));
408 }
409
410 void C1_MacroAssembler::verify_not_null_oop(Register r) {
411 if (!VerifyOops) return;
412 Label not_null;
413 testptr(r, r);
414 jcc(Assembler::notZero, not_null);
415 stop("non-null oop required");
416 bind(not_null);
417 verify_oop(r);
418 }
419
420 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
421 #ifdef ASSERT
422 if (inv_rax) movptr(rax, 0xDEAD);
423 if (inv_rbx) movptr(rbx, 0xDEAD);
424 if (inv_rcx) movptr(rcx, 0xDEAD);
425 if (inv_rdx) movptr(rdx, 0xDEAD);
426 if (inv_rsi) movptr(rsi, 0xDEAD);
427 if (inv_rdi) movptr(rdi, 0xDEAD);
428 #endif
429 }
430
431 #endif // ifndef PRODUCT