1 /*
2 * Copyright (c) 1999, 2022, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2014, 2021, Red Hat Inc. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "c1/c1_MacroAssembler.hpp"
28 #include "c1/c1_Runtime1.hpp"
29 #include "gc/shared/barrierSetAssembler.hpp"
30 #include "gc/shared/collectedHeap.hpp"
31 #include "gc/shared/tlab_globals.hpp"
32 #include "interpreter/interpreter.hpp"
33 #include "oops/arrayOop.hpp"
34 #include "oops/markWord.hpp"
35 #include "runtime/basicLock.hpp"
36 #include "runtime/os.hpp"
37 #include "runtime/sharedRuntime.hpp"
38 #include "runtime/stubRoutines.hpp"
39
40 void C1_MacroAssembler::float_cmp(bool is_float, int unordered_result,
41 FloatRegister f0, FloatRegister f1,
42 Register result)
43 {
44 Label done;
45 if (is_float) {
46 fcmps(f0, f1);
47 } else {
48 fcmpd(f0, f1);
49 }
50 if (unordered_result < 0) {
51 // we want -1 for unordered or less than, 0 for equal and 1 for
52 // greater than.
53 cset(result, NE); // Not equal or unordered
54 cneg(result, result, LT); // Less than or unordered
55 } else {
56 // we want -1 for less than, 0 for equal and 1 for unordered or
57 // greater than.
58 cset(result, NE); // Not equal or unordered
59 cneg(result, result, LO); // Less than
60 }
61 }
62
63 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
64 const int aligned_mask = BytesPerWord -1;
65 const int hdr_offset = oopDesc::mark_offset_in_bytes();
66 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
67 Label done;
68 int null_check_offset = -1;
69
70 verify_oop(obj);
71
72 // save object being locked into the BasicObjectLock
73 str(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
74
75 null_check_offset = offset();
76
77 if (DiagnoseSyncOnValueBasedClasses != 0) {
78 load_klass(hdr, obj);
79 ldrw(hdr, Address(hdr, Klass::access_flags_offset()));
80 tstw(hdr, JVM_ACC_IS_VALUE_BASED_CLASS);
81 br(Assembler::NE, slow_case);
82 }
83
84 // Load object header
85 ldr(hdr, Address(obj, hdr_offset));
86 // and mark it as unlocked
87 orr(hdr, hdr, markWord::unlocked_value);
88 // save unlocked object header into the displaced header location on the stack
89 str(hdr, Address(disp_hdr, 0));
90 // test if object header is still the same (i.e. unlocked), and if so, store the
91 // displaced header address in the object header - if it is not the same, get the
92 // object header instead
93 lea(rscratch2, Address(obj, hdr_offset));
94 cmpxchgptr(hdr, disp_hdr, rscratch2, rscratch1, done, /*fallthough*/NULL);
95 // if the object header was the same, we're done
96 // if the object header was not the same, it is now in the hdr register
97 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
98 //
99 // 1) (hdr & aligned_mask) == 0
100 // 2) sp <= hdr
101 // 3) hdr <= sp + page_size
102 //
103 // these 3 tests can be done by evaluating the following expression:
104 //
105 // (hdr - sp) & (aligned_mask - page_size)
106 //
107 // assuming both the stack pointer and page_size have their least
108 // significant 2 bits cleared and page_size is a power of 2
109 mov(rscratch1, sp);
110 sub(hdr, hdr, rscratch1);
111 ands(hdr, hdr, aligned_mask - os::vm_page_size());
112 // for recursive locking, the result is zero => save it in the displaced header
113 // location (NULL in the displaced hdr location indicates recursive locking)
114 str(hdr, Address(disp_hdr, 0));
115 // otherwise we don't care about the result and handle locking via runtime call
116 cbnz(hdr, slow_case);
117 // done
118 bind(done);
119 increment(Address(rthread, JavaThread::held_monitor_count_offset()));
120 return null_check_offset;
121 }
122
123
124 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
125 const int aligned_mask = BytesPerWord -1;
126 const int hdr_offset = oopDesc::mark_offset_in_bytes();
127 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
128 Label done;
129
130 // load displaced header
131 ldr(hdr, Address(disp_hdr, 0));
132 // if the loaded hdr is NULL we had recursive locking
133 // if we had recursive locking, we are done
134 cbz(hdr, done);
135 // load object
136 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
137 verify_oop(obj);
138 // test if object header is pointing to the displaced header, and if so, restore
139 // the displaced header in the object - if the object header is not pointing to
140 // the displaced header, get the object header instead
141 // if the object header was not pointing to the displaced header,
142 // we do unlocking via runtime call
143 if (hdr_offset) {
144 lea(rscratch1, Address(obj, hdr_offset));
145 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
146 } else {
147 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
148 }
149 // done
150 bind(done);
151 decrement(Address(rthread, JavaThread::held_monitor_count_offset()));
152 }
153
154
155 // Defines obj, preserves var_size_in_bytes
156 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
157 if (UseTLAB) {
158 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
159 } else {
160 b(slow_case);
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);
166 // This assumes that all prototype bits fit in an int32_t
167 mov(t1, (int32_t)(intptr_t)markWord::prototype().value());
168 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
169
170 if (UseCompressedClassPointers) { // Take care not to kill klass
171 encode_klass_not_null(t1, klass);
172 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
173 } else {
174 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
175 }
176
177 if (len->is_valid()) {
178 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
179 } else if (UseCompressedClassPointers) {
180 store_klass_gap(obj, zr);
181 }
182 }
183
184 // preserves obj, destroys len_in_bytes
185 //
186 // Scratch registers: t1 = r10, t2 = r11
187 //
188 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1, Register t2) {
189 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
190 assert(t1 == r10 && t2 == r11, "must be");
191
192 Label done;
193
194 // len_in_bytes is positive and ptr sized
195 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
196 br(Assembler::EQ, done);
197
198 // zero_words() takes ptr in r10 and count in words in r11
199 mov(rscratch1, len_in_bytes);
200 lea(t1, Address(obj, hdr_size_in_bytes));
201 lsr(t2, rscratch1, LogBytesPerWord);
202 zero_words(t1, t2);
203
204 bind(done);
205 }
206
207
208 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
209 assert_different_registers(obj, t1, t2); // XXX really?
210 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
211
212 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
213
214 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
215 }
216
217 // Scratch registers: t1 = r10, t2 = r11
218 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) {
219 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
220 "con_size_in_bytes is not multiple of alignment");
221 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
222
223 initialize_header(obj, klass, noreg, t1, t2);
224
225 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
226 // clear rest of allocated space
227 const Register index = t2;
228 if (var_size_in_bytes != noreg) {
229 mov(index, var_size_in_bytes);
230 initialize_body(obj, index, hdr_size_in_bytes, t1, t2);
231 } else if (con_size_in_bytes > hdr_size_in_bytes) {
232 con_size_in_bytes -= hdr_size_in_bytes;
233 lea(t1, Address(obj, hdr_size_in_bytes));
234 zero_words(t1, con_size_in_bytes / BytesPerWord);
235 }
236 }
237
238 membar(StoreStore);
239
240 if (CURRENT_ENV->dtrace_alloc_probes()) {
241 assert(obj == r0, "must be");
242 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
243 }
244
245 verify_oop(obj);
246 }
247 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
248 assert_different_registers(obj, len, t1, t2, klass);
249
250 // determine alignment mask
251 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
252
253 // check for negative or excessive length
254 mov(rscratch1, (int32_t)max_array_allocation_length);
255 cmp(len, rscratch1);
256 br(Assembler::HS, slow_case);
257
258 const Register arr_size = t2; // okay to be the same
259 // align object end
260 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
261 add(arr_size, arr_size, len, ext::uxtw, f);
262 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
263
264 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
265
266 initialize_header(obj, klass, len, t1, t2);
267
268 // clear rest of allocated space
269 initialize_body(obj, arr_size, header_size * BytesPerWord, t1, t2);
270
271 membar(StoreStore);
272
273 if (CURRENT_ENV->dtrace_alloc_probes()) {
274 assert(obj == r0, "must be");
275 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
276 }
277
278 verify_oop(obj);
279 }
280
281
282 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
283 verify_oop(receiver);
284 // explicit NULL check not needed since load from [klass_offset] causes a trap
285 // check against inline cache
286 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
287
288 cmp_klass(receiver, iCache, rscratch1);
289 }
290
291
292 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
293 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
294 // Make sure there is enough stack space for this method's activation.
295 // Note that we do this before creating a frame.
296 generate_stack_overflow_check(bang_size_in_bytes);
297 MacroAssembler::build_frame(framesize);
298
299 // Insert nmethod entry barrier into frame.
300 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
301 bs->nmethod_entry_barrier(this, NULL /* slow_path */, NULL /* continuation */, NULL /* guard */);
302 }
303
304 void C1_MacroAssembler::remove_frame(int framesize) {
305 MacroAssembler::remove_frame(framesize);
306 }
307
308
309 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
310 // If we have to make this method not-entrant we'll overwrite its
311 // first instruction with a jump. For this action to be legal we
312 // must ensure that this first instruction is a B, BL, NOP, BKPT,
313 // SVC, HVC, or SMC. Make it a NOP.
314 nop();
315 }
316
317 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
318 // rfp, + 0: link
319 // + 1: return address
320 // + 2: argument with offset 0
321 // + 3: argument with offset 1
322 // + 4: ...
323
324 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
325 }
326
327 #ifndef PRODUCT
328
329 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
330 if (!VerifyOops) return;
331 verify_oop_addr(Address(sp, stack_offset));
332 }
333
334 void C1_MacroAssembler::verify_not_null_oop(Register r) {
335 if (!VerifyOops) return;
336 Label not_null;
337 cbnz(r, not_null);
338 stop("non-null oop required");
339 bind(not_null);
340 verify_oop(r);
341 }
342
343 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
344 #ifdef ASSERT
345 static int nn;
346 if (inv_r0) mov(r0, 0xDEAD);
347 if (inv_r19) mov(r19, 0xDEAD);
348 if (inv_r2) mov(r2, nn++);
349 if (inv_r3) mov(r3, 0xDEAD);
350 if (inv_r4) mov(r4, 0xDEAD);
351 if (inv_r5) mov(r5, 0xDEAD);
352 #endif
353 }
354 #endif // ifndef PRODUCT