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.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "c1/c1_MacroAssembler.hpp"
27 #include "c1/c1_Runtime1.hpp"
28 #include "code/compiledIC.hpp"
29 #include "compiler/compilerDefinitions.inline.hpp"
30 #include "gc/shared/barrierSet.hpp"
31 #include "gc/shared/barrierSetAssembler.hpp"
32 #include "gc/shared/collectedHeap.hpp"
33 #include "gc/shared/tlab_globals.hpp"
34 #include "interpreter/interpreter.hpp"
35 #include "oops/arrayOop.hpp"
36 #include "oops/markWord.hpp"
37 #include "runtime/basicLock.hpp"
38 #include "runtime/globals.hpp"
39 #include "runtime/os.hpp"
40 #include "runtime/sharedRuntime.hpp"
41 #include "runtime/stubRoutines.hpp"
42 #include "utilities/checkedCast.hpp"
43 #include "utilities/globalDefinitions.hpp"
44
45 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Register tmp, Label& slow_case) {
46 const int aligned_mask = BytesPerWord -1;
47 const int hdr_offset = oopDesc::mark_offset_in_bytes();
48 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
49 assert_different_registers(hdr, obj, disp_hdr, tmp);
50 int null_check_offset = -1;
51
52 verify_oop(obj);
53
54 // save object being locked into the BasicObjectLock
55 movptr(Address(disp_hdr, BasicObjectLock::obj_offset()), obj);
56
57 null_check_offset = offset();
58
59 if (DiagnoseSyncOnValueBasedClasses != 0) {
60 load_klass(hdr, obj, rscratch1);
61 movl(hdr, Address(hdr, Klass::access_flags_offset()));
62 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
63 jcc(Assembler::notZero, slow_case);
64 }
65
66 if (LockingMode == LM_LIGHTWEIGHT) {
67 #ifdef _LP64
68 const Register thread = r15_thread;
69 #else
70 const Register thread = disp_hdr;
71 get_thread(thread);
72 #endif
73 lightweight_lock(obj, hdr, thread, tmp, slow_case);
74 } else if (LockingMode == LM_LEGACY) {
75 Label done;
76 // Load object header
77 movptr(hdr, Address(obj, hdr_offset));
78 // and mark it as unlocked
79 orptr(hdr, markWord::unlocked_value);
80 // save unlocked object header into the displaced header location on the stack
81 movptr(Address(disp_hdr, 0), hdr);
82 // test if object header is still the same (i.e. unlocked), and if so, store the
83 // displaced header address in the object header - if it is not the same, get the
84 // object header instead
85 MacroAssembler::lock(); // must be immediately before cmpxchg!
86 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
87 // if the object header was the same, we're done
88 jcc(Assembler::equal, done);
89 // if the object header was not the same, it is now in the hdr register
90 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
91 //
92 // 1) (hdr & aligned_mask) == 0
93 // 2) rsp <= hdr
94 // 3) hdr <= rsp + page_size
95 //
96 // these 3 tests can be done by evaluating the following expression:
97 //
98 // (hdr - rsp) & (aligned_mask - page_size)
99 //
100 // assuming both the stack pointer and page_size have their least
101 // significant 2 bits cleared and page_size is a power of 2
102 subptr(hdr, rsp);
103 andptr(hdr, aligned_mask - (int)os::vm_page_size());
104 // for recursive locking, the result is zero => save it in the displaced header
105 // location (null in the displaced hdr location indicates recursive locking)
106 movptr(Address(disp_hdr, 0), hdr);
107 // otherwise we don't care about the result and handle locking via runtime call
108 jcc(Assembler::notZero, slow_case);
109 // done
110 bind(done);
111 }
112
113 inc_held_monitor_count();
114
115 return null_check_offset;
116 }
117
118 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
119 const int aligned_mask = BytesPerWord -1;
120 const int hdr_offset = oopDesc::mark_offset_in_bytes();
121 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
122 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
123 Label done;
124
125 if (LockingMode != LM_LIGHTWEIGHT) {
126 // load displaced header
127 movptr(hdr, Address(disp_hdr, 0));
128 // if the loaded hdr is null we had recursive locking
129 testptr(hdr, hdr);
130 // if we had recursive locking, we are done
131 jcc(Assembler::zero, done);
132 }
133
134 // load object
135 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
136 verify_oop(obj);
137
138 if (LockingMode == LM_LIGHTWEIGHT) {
139 #ifdef _LP64
140 lightweight_unlock(obj, disp_hdr, r15_thread, hdr, slow_case);
141 #else
142 // This relies on the implementation of lightweight_unlock being able to handle
143 // that the reg_rax and thread Register parameters may alias each other.
144 get_thread(disp_hdr);
145 lightweight_unlock(obj, disp_hdr, disp_hdr, hdr, slow_case);
146 #endif
147 } else if (LockingMode == LM_LEGACY) {
148 // test if object header is pointing to the displaced header, and if so, restore
149 // the displaced header in the object - if the object header is not pointing to
150 // the displaced header, get the object header instead
151 MacroAssembler::lock(); // must be immediately before cmpxchg!
152 cmpxchgptr(hdr, Address(obj, hdr_offset));
153 // if the object header was not pointing to the displaced header,
154 // we do unlocking via runtime call
155 jcc(Assembler::notEqual, slow_case);
156 // done
157 }
158 bind(done);
159 dec_held_monitor_count();
160 }
161
162
163 // Defines obj, preserves var_size_in_bytes
164 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
165 if (UseTLAB) {
166 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
167 } else {
168 jmp(slow_case);
169 }
170 }
171
172
173 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
174 assert_different_registers(obj, klass, len);
175 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
176 #ifdef _LP64
177 if (UseCompressedClassPointers) { // Take care not to kill klass
178 movptr(t1, klass);
179 encode_klass_not_null(t1, rscratch1);
180 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
181 } else
182 #endif
183 {
184 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
185 }
186
187 if (len->is_valid()) {
188 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
189 }
190 #ifdef _LP64
191 else if (UseCompressedClassPointers) {
192 xorptr(t1, t1);
193 store_klass_gap(obj, t1);
194 }
195 #endif
196 }
197
198
199 // preserves obj, destroys len_in_bytes
200 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
201 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
202 Label done;
203
204 // len_in_bytes is positive and ptr sized
205 subptr(len_in_bytes, hdr_size_in_bytes);
206 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
207 bind(done);
208 }
209
210
211 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
212 assert(obj == rax, "obj must be in rax, for cmpxchg");
213 assert_different_registers(obj, t1, t2); // XXX really?
214 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
215
216 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
217
218 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
219 }
220
221 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) {
222 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
223 "con_size_in_bytes is not multiple of alignment");
224 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
225
226 initialize_header(obj, klass, noreg, t1, t2);
227
228 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
229 // clear rest of allocated space
230 const Register t1_zero = t1;
231 const Register index = t2;
232 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
233 if (var_size_in_bytes != noreg) {
234 mov(index, var_size_in_bytes);
235 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
236 } else if (con_size_in_bytes <= threshold) {
237 // use explicit null stores
238 // code size = 2 + 3*n bytes (n = number of fields to clear)
239 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
240 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
241 movptr(Address(obj, i), t1_zero);
242 } else if (con_size_in_bytes > hdr_size_in_bytes) {
243 // use loop to null out the fields
244 // code size = 16 bytes for even n (n = number of fields to clear)
245 // initialize last object field first if odd number of fields
246 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
247 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
248 // initialize last object field if constant size is odd
249 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
250 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
251 // initialize remaining object fields: rdx is a multiple of 2
252 { Label loop;
253 bind(loop);
254 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
255 t1_zero);
256 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)),
257 t1_zero);)
258 decrement(index);
259 jcc(Assembler::notZero, loop);
260 }
261 }
262 }
263
264 if (CURRENT_ENV->dtrace_alloc_probes()) {
265 assert(obj == rax, "must be");
266 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
267 }
268
269 verify_oop(obj);
270 }
271
272 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) {
273 assert(obj == rax, "obj must be in rax, for cmpxchg");
274 assert_different_registers(obj, len, t1, t2, klass);
275
276 // determine alignment mask
277 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
278
279 // check for negative or excessive length
280 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length));
281 jcc(Assembler::above, slow_case);
282
283 const Register arr_size = t2; // okay to be the same
284 // align object end
285 movptr(arr_size, header_size * BytesPerWord + MinObjAlignmentInBytesMask);
286 lea(arr_size, Address(arr_size, len, f));
287 andptr(arr_size, ~MinObjAlignmentInBytesMask);
288
289 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
290
291 initialize_header(obj, klass, len, t1, t2);
292
293 // clear rest of allocated space
294 const Register len_zero = len;
295 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
296
297 if (CURRENT_ENV->dtrace_alloc_probes()) {
298 assert(obj == rax, "must be");
299 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
300 }
301
302 verify_oop(obj);
303 }
304
305 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
306 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
307 // Make sure there is enough stack space for this method's activation.
308 // Note that we do this before doing an enter(). This matches the
309 // ordering of C2's stack overflow check / rsp decrement and allows
310 // the SharedRuntime stack overflow handling to be consistent
311 // between the two compilers.
312 generate_stack_overflow_check(bang_size_in_bytes);
313
314 push(rbp);
315 if (PreserveFramePointer) {
316 mov(rbp, rsp);
317 }
318 #if !defined(_LP64) && defined(COMPILER2)
319 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) {
320 // c2 leaves fpu stack dirty. Clean it on entry
321 empty_FPU_stack();
322 }
323 #endif // !_LP64 && COMPILER2
324 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
325
326 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
327 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
328 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */);
329 }
330
331
332 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
333 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
334 pop(rbp);
335 }
336
337
338 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
339 if (breakAtEntry || VerifyFPU) {
340 // Verified Entry first instruction should be 5 bytes long for correct
341 // patching by patch_verified_entry().
342 //
343 // Breakpoint and VerifyFPU have one byte first instruction.
344 // Also first instruction will be one byte "push(rbp)" if stack banging
345 // code is not generated (see build_frame() above).
346 // For all these cases generate long instruction first.
347 fat_nop();
348 }
349 if (breakAtEntry) int3();
350 // build frame
351 IA32_ONLY( verify_FPU(0, "method_entry"); )
352 }
353
354 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
355 // rbp, + 0: link
356 // + 1: return address
357 // + 2: argument with offset 0
358 // + 3: argument with offset 1
359 // + 4: ...
360
361 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
362 }
363
364 #ifndef PRODUCT
365
366 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
367 if (!VerifyOops) return;
368 verify_oop_addr(Address(rsp, stack_offset));
369 }
370
371 void C1_MacroAssembler::verify_not_null_oop(Register r) {
372 if (!VerifyOops) return;
373 Label not_null;
374 testptr(r, r);
375 jcc(Assembler::notZero, not_null);
376 stop("non-null oop required");
377 bind(not_null);
378 verify_oop(r);
379 }
380
381 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
382 #ifdef ASSERT
383 if (inv_rax) movptr(rax, 0xDEAD);
384 if (inv_rbx) movptr(rbx, 0xDEAD);
385 if (inv_rcx) movptr(rcx, 0xDEAD);
386 if (inv_rdx) movptr(rdx, 0xDEAD);
387 if (inv_rsi) movptr(rsi, 0xDEAD);
388 if (inv_rdi) movptr(rdi, 0xDEAD);
389 #endif
390 }
391
392 #endif // ifndef PRODUCT