1 /*
2 * Copyright (c) 1999, 2021, 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 return null_check_offset;
120 }
121
122
123 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
124 const int aligned_mask = BytesPerWord -1;
125 const int hdr_offset = oopDesc::mark_offset_in_bytes();
126 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
127 Label done;
128
129 // load displaced header
130 ldr(hdr, Address(disp_hdr, 0));
131 // if the loaded hdr is NULL we had recursive locking
132 // if we had recursive locking, we are done
133 cbz(hdr, done);
134 // load object
135 ldr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
136 verify_oop(obj);
137 // test if object header is pointing to the displaced header, and if so, restore
138 // the displaced header in the object - if the object header is not pointing to
139 // the displaced header, get the object header instead
140 // if the object header was not pointing to the displaced header,
141 // we do unlocking via runtime call
142 if (hdr_offset) {
143 lea(rscratch1, Address(obj, hdr_offset));
144 cmpxchgptr(disp_hdr, hdr, rscratch1, rscratch2, done, &slow_case);
145 } else {
146 cmpxchgptr(disp_hdr, hdr, obj, rscratch2, done, &slow_case);
147 }
148 // done
149 bind(done);
150 }
151
152
153 // Defines obj, preserves var_size_in_bytes
154 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
155 if (UseTLAB) {
156 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
157 } else {
158 eden_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, slow_case);
159 }
160 }
161
162 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
163 assert_different_registers(obj, klass, len);
164 ldr(t1, Address(klass, Klass::prototype_header_offset()));
165 str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
166
167 if (UseCompressedClassPointers) { // Take care not to kill klass
168 encode_klass_not_null(t1, klass);
169 strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
170 } else {
171 str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
172 }
173
174 if (len->is_valid()) {
175 strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
176 } else if (UseCompressedClassPointers) {
177 store_klass_gap(obj, zr);
178 }
179 }
180
181 // preserves obj, destroys len_in_bytes
182 //
183 // Scratch registers: t1 = r10, t2 = r11
184 //
185 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1, Register t2) {
186 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
187 assert(t1 == r10 && t2 == r11, "must be");
188
189 Label done;
190
191 // len_in_bytes is positive and ptr sized
192 subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
193 br(Assembler::EQ, done);
194
195 // zero_words() takes ptr in r10 and count in words in r11
196 mov(rscratch1, len_in_bytes);
197 lea(t1, Address(obj, hdr_size_in_bytes));
198 lsr(t2, rscratch1, LogBytesPerWord);
199 zero_words(t1, t2);
200
201 bind(done);
202 }
203
204
205 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
206 assert_different_registers(obj, t1, t2); // XXX really?
207 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
208
209 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
210
211 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
212 }
213
214 // Scratch registers: t1 = r10, t2 = r11
215 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) {
216 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
217 "con_size_in_bytes is not multiple of alignment");
218 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
219
220 initialize_header(obj, klass, noreg, t1, t2);
221
222 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
223 // clear rest of allocated space
224 const Register index = t2;
225 if (var_size_in_bytes != noreg) {
226 mov(index, var_size_in_bytes);
227 initialize_body(obj, index, hdr_size_in_bytes, t1, t2);
228 } else if (con_size_in_bytes > hdr_size_in_bytes) {
229 con_size_in_bytes -= hdr_size_in_bytes;
230 lea(t1, Address(obj, hdr_size_in_bytes));
231 zero_words(t1, con_size_in_bytes / BytesPerWord);
232 }
233 }
234
235 membar(StoreStore);
236
237 if (CURRENT_ENV->dtrace_alloc_probes()) {
238 assert(obj == r0, "must be");
239 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
240 }
241
242 verify_oop(obj);
243 }
244 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
245 assert_different_registers(obj, len, t1, t2, klass);
246
247 // determine alignment mask
248 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
249
250 // check for negative or excessive length
251 mov(rscratch1, (int32_t)max_array_allocation_length);
252 cmp(len, rscratch1);
253 br(Assembler::HS, slow_case);
254
255 const Register arr_size = t2; // okay to be the same
256 // align object end
257 mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
258 add(arr_size, arr_size, len, ext::uxtw, f);
259 andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
260
261 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
262
263 initialize_header(obj, klass, len, t1, t2);
264
265 // clear rest of allocated space
266 initialize_body(obj, arr_size, header_size * BytesPerWord, t1, t2);
267
268 membar(StoreStore);
269
270 if (CURRENT_ENV->dtrace_alloc_probes()) {
271 assert(obj == r0, "must be");
272 far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
273 }
274
275 verify_oop(obj);
276 }
277
278
279 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
280 verify_oop(receiver);
281 // explicit NULL check not needed since load from [klass_offset] causes a trap
282 // check against inline cache
283 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
284
285 cmp_klass(receiver, iCache, rscratch1);
286 }
287
288
289 void C1_MacroAssembler::build_frame(int framesize, int bang_size_in_bytes) {
290 assert(bang_size_in_bytes >= framesize, "stack bang size incorrect");
291 // Make sure there is enough stack space for this method's activation.
292 // Note that we do this before creating a frame.
293 generate_stack_overflow_check(bang_size_in_bytes);
294 MacroAssembler::build_frame(framesize);
295
296 // Insert nmethod entry barrier into frame.
297 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
298 bs->nmethod_entry_barrier(this);
299 }
300
301 void C1_MacroAssembler::remove_frame(int framesize) {
302 MacroAssembler::remove_frame(framesize);
303 }
304
305
306 void C1_MacroAssembler::verified_entry() {
307 // If we have to make this method not-entrant we'll overwrite its
308 // first instruction with a jump. For this action to be legal we
309 // must ensure that this first instruction is a B, BL, NOP, BKPT,
310 // SVC, HVC, or SMC. Make it a NOP.
311 nop();
312 }
313
314 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
315 // rbp, + 0: link
316 // + 1: return address
317 // + 2: argument with offset 0
318 // + 3: argument with offset 1
319 // + 4: ...
320
321 ldr(reg, Address(rfp, (offset_in_words + 2) * BytesPerWord));
322 }
323
324 #ifndef PRODUCT
325
326 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
327 if (!VerifyOops) return;
328 verify_oop_addr(Address(sp, stack_offset), "oop");
329 }
330
331 void C1_MacroAssembler::verify_not_null_oop(Register r) {
332 if (!VerifyOops) return;
333 Label not_null;
334 cbnz(r, not_null);
335 stop("non-null oop required");
336 bind(not_null);
337 verify_oop(r);
338 }
339
340 void C1_MacroAssembler::invalidate_registers(bool inv_r0, bool inv_r19, bool inv_r2, bool inv_r3, bool inv_r4, bool inv_r5) {
341 #ifdef ASSERT
342 static int nn;
343 if (inv_r0) mov(r0, 0xDEAD);
344 if (inv_r19) mov(r19, 0xDEAD);
345 if (inv_r2) mov(r2, nn++);
346 if (inv_r3) mov(r3, 0xDEAD);
347 if (inv_r4) mov(r4, 0xDEAD);
348 if (inv_r5) mov(r5, 0xDEAD);
349 #endif
350 }
351 #endif // ifndef PRODUCT