1 /*
2 * Copyright (c) 1999, 2023, 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 "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/os.hpp"
38 #include "runtime/sharedRuntime.hpp"
39 #include "runtime/stubRoutines.hpp"
40
41 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register tmp, Label& slow_case) {
42 const int aligned_mask = BytesPerWord -1;
43 const int hdr_offset = oopDesc::mark_offset_in_bytes();
44 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
45 assert_different_registers(hdr, obj, disp_hdr, tmp);
46 int null_check_offset = -1;
47
48 verify_oop(obj);
49
50 // save object being locked into the BasicObjectLock
51 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj);
52
53 null_check_offset = offset();
54
55 if (DiagnoseSyncOnValueBasedClasses != 0) {
56 load_klass(hdr, obj, rscratch1);
57 movl(hdr, Address(hdr, Klass::access_flags_offset()));
58 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
59 jcc(Assembler::notZero, slow_case);
60 }
61
62 // Load object header
63 movptr(hdr, Address(obj, hdr_offset));
64
65 if (UseFastLocking) {
66 #ifdef _LP64
67 const Register thread = r15_thread;
68 #else
69 const Register thread = disp_hdr;
70 get_thread(thread);
71 #endif
72 fast_lock_impl(obj, hdr, thread, tmp, slow_case, LP64_ONLY(false) NOT_LP64(true));
73 } else {
74 Label done;
75 orptr(hdr, markWord::unlocked_value);
76 // save unlocked object header into the displaced header location on the stack
77 movptr(Address(disp_hdr, 0), hdr);
78 // test if object header is still the same (i.e. unlocked), and if so, store the
79 // displaced header address in the object header - if it is not the same, get the
80 // object header instead
81 MacroAssembler::lock(); // must be immediately before cmpxchg!
82 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
83 // if the object header was the same, we're done
84 jcc(Assembler::equal, done);
85 // if the object header was not the same, it is now in the hdr register
86 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
87 //
88 // 1) (hdr & aligned_mask) == 0
89 // 2) rsp <= hdr
90 // 3) hdr <= rsp + page_size
91 //
92 // these 3 tests can be done by evaluating the following expression:
93 //
94 // (hdr - rsp) & (aligned_mask - page_size)
95 //
96 // assuming both the stack pointer and page_size have their least
97 // significant 2 bits cleared and page_size is a power of 2
98 subptr(hdr, rsp);
99 andptr(hdr, aligned_mask - (int)os::vm_page_size());
100 // for recursive locking, the result is zero => save it in the displaced header
101 // location (NULL in the displaced hdr location indicates recursive locking)
102 movptr(Address(disp_hdr, 0), hdr);
103 // otherwise we don't care about the result and handle locking via runtime call
104 jcc(Assembler::notZero, slow_case);
105 // done
106 bind(done);
107 }
108
109 inc_held_monitor_count();
110
111 return null_check_offset;
112 }
113
114 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
115 const int aligned_mask = BytesPerWord -1;
116 const int hdr_offset = oopDesc::mark_offset_in_bytes();
117 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
118 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
119 Label done;
120
121 if (!UseFastLocking) {
122 // load displaced header
123 movptr(hdr, Address(disp_hdr, 0));
124 // if the loaded hdr is NULL we had recursive locking
125 testptr(hdr, hdr);
126 // if we had recursive locking, we are done
127 jcc(Assembler::zero, done);
128 }
129
130 // load object
131 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
132 verify_oop(obj);
133
134 if (UseFastLocking) {
135 movptr(disp_hdr, Address(obj, hdr_offset));
136 andptr(disp_hdr, ~(int32_t)markWord::lock_mask_in_place);
137 fast_unlock_impl(obj, disp_hdr, hdr, slow_case);
138 } else {
139 // test if object header is pointing to the displaced header, and if so, restore
140 // the displaced header in the object - if the object header is not pointing to
141 // the displaced header, get the object header instead
142 MacroAssembler::lock(); // must be immediately before cmpxchg!
143 cmpxchgptr(hdr, Address(obj, hdr_offset));
144 // if the object header was not pointing to the displaced header,
145 // we do unlocking via runtime call
146 jcc(Assembler::notEqual, slow_case);
147 // done
148 }
149 bind(done);
150 dec_held_monitor_count();
151 }
152
153
154 // Defines obj, preserves var_size_in_bytes
155 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
156 if (UseTLAB) {
157 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
158 } else {
159 jmp(slow_case);
160 }
161 }
162
163
164 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
165 assert_different_registers(obj, klass, len, t1, t2);
166 if (UseCompactObjectHeaders) {
167 movptr(t1, Address(klass, Klass::prototype_header_offset()));
168 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
169 } else {
170 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
171 #ifdef _LP64
172 if (UseCompressedClassPointers) { // Take care not to kill klass
173 movptr(t1, klass);
174 encode_klass_not_null(t1, rscratch1);
175 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
176 } else
177 #endif
178 {
179 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
180 }
181 }
182 if (len->is_valid()) {
183 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
184 }
185 #ifdef _LP64
186 else if (UseCompressedClassPointers && !UseCompactObjectHeaders) {
187 xorptr(t1, t1);
188 store_klass_gap(obj, t1);
189 }
190 #endif
191 }
192
193
194 // preserves obj, destroys len_in_bytes
195 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
196 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
197 Label done;
198
199 // len_in_bytes is positive and ptr sized
200 subptr(len_in_bytes, hdr_size_in_bytes);
201 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
202 bind(done);
203 }
204
205
206 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
207 assert(obj == rax, "obj must be in rax, for cmpxchg");
208 assert_different_registers(obj, t1, t2); // XXX really?
209 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
210
211 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
212
213 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
214 }
215
216 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) {
217 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
218 "con_size_in_bytes is not multiple of alignment");
219 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
220
221 initialize_header(obj, klass, noreg, t1, t2);
222
223 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
224 // clear rest of allocated space
225 const Register t1_zero = t1;
226 const Register index = t2;
227 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
228 int hdr_size_aligned = align_up(hdr_size_in_bytes, BytesPerWord); // klass gap is already cleared by init_header().
229 if (var_size_in_bytes != noreg) {
230 mov(index, var_size_in_bytes);
231 initialize_body(obj, index, hdr_size_aligned, t1_zero);
232 } else if (con_size_in_bytes <= threshold) {
233 // use explicit null stores
234 // code size = 2 + 3*n bytes (n = number of fields to clear)
235 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
236 for (int i = hdr_size_aligned; i < con_size_in_bytes; i += BytesPerWord)
237 movptr(Address(obj, i), t1_zero);
238 } else if (con_size_in_bytes > hdr_size_aligned) {
239 // use loop to null out the fields
240 // code size = 16 bytes for even n (n = number of fields to clear)
241 // initialize last object field first if odd number of fields
242 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
243 movptr(index, (con_size_in_bytes - hdr_size_aligned) >> 3);
244 // initialize last object field if constant size is odd
245 if (((con_size_in_bytes - hdr_size_aligned) & 4) != 0)
246 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
247 // initialize remaining object fields: rdx is a multiple of 2
248 { Label loop;
249 bind(loop);
250 movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (1*BytesPerWord)),
251 t1_zero);
252 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_aligned - (2*BytesPerWord)),
253 t1_zero);)
254 decrement(index);
255 jcc(Assembler::notZero, loop);
256 }
257 }
258 }
259
260 if (CURRENT_ENV->dtrace_alloc_probes()) {
261 assert(obj == rax, "must be");
262 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
263 }
264
265 verify_oop(obj);
266 }
267
268 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) {
269 assert(obj == rax, "obj must be in rax, for cmpxchg");
270 assert_different_registers(obj, len, t1, t2, klass);
271
272 // determine alignment mask
273 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
274
275 // check for negative or excessive length
276 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length));
277 jcc(Assembler::above, slow_case);
278
279 const Register arr_size = t2; // okay to be the same
280 // align object end
281 movptr(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
282 lea(arr_size, Address(arr_size, len, f));
283 andptr(arr_size, ~MinObjAlignmentInBytesMask);
284
285 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
286
287 initialize_header(obj, klass, len, t1, t2);
288
289 // clear rest of allocated space
290 const Register len_zero = len;
291 initialize_body(obj, arr_size, base_offset_in_bytes, len_zero);
292
293 if (CURRENT_ENV->dtrace_alloc_probes()) {
294 assert(obj == rax, "must be");
295 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
296 }
297
298 verify_oop(obj);
299 }
300
301
302
303 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
304 verify_oop(receiver);
305 // explicit NULL check not needed since load from [klass_offset] causes a trap
306 // check against inline cache
307 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
308 int start_offset = offset();
309
310 if (UseCompressedClassPointers) {
311 load_klass(rscratch1, receiver, rscratch2);
312 cmpptr(rscratch1, iCache);
313 } else {
314 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes()));
315 }
316 // if icache check fails, then jump to runtime routine
317 // Note: RECEIVER must still contain the receiver!
318 jump_cc(Assembler::notEqual,
319 RuntimeAddress(SharedRuntime::get_ic_miss_stub()));
320 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9);
321 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry");
322 }
323
324
325 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes, int max_monitors) {
326 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
327 // Make sure there is enough stack space for this method's activation.
328 // Note that we do this before doing an enter(). This matches the
329 // ordering of C2's stack overflow check / rsp decrement and allows
330 // the SharedRuntime stack overflow handling to be consistent
331 // between the two compilers.
332 generate_stack_overflow_check(bang_size_in_bytes);
333
334 push(rbp);
335 if (PreserveFramePointer) {
336 mov(rbp, rsp);
337 }
338 #if !defined(_LP64) && defined(COMPILER2)
339 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) {
340 // c2 leaves fpu stack dirty. Clean it on entry
341 empty_FPU_stack();
342 }
343 #endif // !_LP64 && COMPILER2
344 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
345
346 #ifdef _LP64
347 if (UseFastLocking && max_monitors > 0) {
348 Label ok;
349 movptr(rax, Address(r15_thread, JavaThread::lock_stack_current_offset()));
350 addptr(rax, max_monitors * wordSize);
351 cmpptr(rax, Address(r15_thread, JavaThread::lock_stack_limit_offset()));
352 jcc(Assembler::less, ok);
353 assert(StubRoutines::x86::check_lock_stack() != NULL, "need runtime call stub");
354 call(RuntimeAddress(StubRoutines::x86::check_lock_stack()));
355 bind(ok);
356 }
357 #endif
358
359 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
360 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
361 bs->nmethod_entry_barrier(this, NULL /* slow_path */, NULL /* continuation */);
362 }
363
364
365 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
366 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
367 pop(rbp);
368 }
369
370
371 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
372 if (breakAtEntry || VerifyFPU) {
373 // Verified Entry first instruction should be 5 bytes long for correct
374 // patching by patch_verified_entry().
375 //
376 // Breakpoint and VerifyFPU have one byte first instruction.
377 // Also first instruction will be one byte "push(rbp)" if stack banging
378 // code is not generated (see build_frame() above).
379 // For all these cases generate long instruction first.
380 fat_nop();
381 }
382 if (breakAtEntry) int3();
383 // build frame
384 IA32_ONLY( verify_FPU(0, "method_entry"); )
385 }
386
387 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
388 // rbp, + 0: link
389 // + 1: return address
390 // + 2: argument with offset 0
391 // + 3: argument with offset 1
392 // + 4: ...
393
394 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
395 }
396
397 #ifndef PRODUCT
398
399 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
400 if (!VerifyOops) return;
401 verify_oop_addr(Address(rsp, stack_offset));
402 }
403
404 void C1_MacroAssembler::verify_not_null_oop(Register r) {
405 if (!VerifyOops) return;
406 Label not_null;
407 testptr(r, r);
408 jcc(Assembler::notZero, not_null);
409 stop("non-null oop required");
410 bind(not_null);
411 verify_oop(r);
412 }
413
414 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
415 #ifdef ASSERT
416 if (inv_rax) movptr(rax, 0xDEAD);
417 if (inv_rbx) movptr(rbx, 0xDEAD);
418 if (inv_rcx) movptr(rcx, 0xDEAD);
419 if (inv_rdx) movptr(rdx, 0xDEAD);
420 if (inv_rsi) movptr(rsi, 0xDEAD);
421 if (inv_rdi) movptr(rdi, 0xDEAD);
422 #endif
423 }
424
425 #endif // ifndef PRODUCT