1 /*
2 * Copyright (c) 1999, 2026, 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 "c1/c1_MacroAssembler.hpp"
26 #include "c1/c1_Runtime1.hpp"
27 #include "code/compiledIC.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/checkedCast.hpp"
42 #include "utilities/globalDefinitions.hpp"
43
44 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register basic_lock, Register tmp, Label& slow_case) {
45 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction");
46 assert_different_registers(hdr, obj, basic_lock, tmp);
47 int null_check_offset = -1;
48
49 verify_oop(obj);
50
51 // save object being locked into the BasicObjectLock
52 movptr(Address(basic_lock, BasicObjectLock::obj_offset()), obj);
53
54 null_check_offset = offset();
55
56 fast_lock(basic_lock, obj, hdr, tmp, slow_case);
57
58 return null_check_offset;
59 }
60
61 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register basic_lock, Label& slow_case) {
62 assert(basic_lock == rax, "basic_lock must be rax, for the cmpxchg instruction");
63 assert(hdr != obj && hdr != basic_lock && obj != basic_lock, "registers must be different");
64
65 // load object
66 movptr(obj, Address(basic_lock, BasicObjectLock::obj_offset()));
67 verify_oop(obj);
68
69 fast_unlock(obj, rax, hdr, slow_case);
70 }
71
72
73 // Defines obj, preserves var_size_in_bytes
74 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) {
75 if (UseTLAB) {
76 tlab_allocate(obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case);
77 } else {
78 jmp(slow_case);
79 }
80 }
81
82
83 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
84 assert_different_registers(obj, klass, len, t1, t2);
85 if (UseCompactObjectHeaders) {
86 movptr(t1, Address(klass, Klass::prototype_header_offset()));
87 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
88 } else { // Take care not to kill klass
89 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
90 movptr(t1, klass);
91 encode_klass_not_null(t1, rscratch1);
92 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
93 }
94
95 if (len->is_valid()) {
96 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
97 int base_offset = arrayOopDesc::length_offset_in_bytes() + BytesPerInt;
98 if (!is_aligned(base_offset, BytesPerWord)) {
99 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned");
100 // Clear gap/first 4 bytes following the length field.
101 xorl(t1, t1);
102 movl(Address(obj, base_offset), t1);
103 }
104 } else if (!UseCompactObjectHeaders) {
105 xorptr(t1, t1);
106 store_klass_gap(obj, t1);
107 }
108 }
109
110
111 // preserves obj, destroys len_in_bytes
112 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
113 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
114 Label done;
115
116 // len_in_bytes is positive and ptr sized
117 subptr(len_in_bytes, hdr_size_in_bytes);
118 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
119 bind(done);
120 }
121
122
123 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
124 assert(obj == rax, "obj must be in rax, for cmpxchg");
125 assert_different_registers(obj, t1, t2); // XXX really?
126 assert(header_size >= 0 && object_size >= header_size, "illegal sizes");
127
128 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case);
129
130 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB);
131 }
132
133 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) {
134 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
135 "con_size_in_bytes is not multiple of alignment");
136 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
137 if (UseCompactObjectHeaders) {
138 assert(hdr_size_in_bytes == 8, "check object headers size");
139 }
140 initialize_header(obj, klass, noreg, t1, t2);
141
142 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
143 // clear rest of allocated space
144 const Register t1_zero = t1;
145 const Register index = t2;
146 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
147 if (var_size_in_bytes != noreg) {
148 mov(index, var_size_in_bytes);
149 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
150 } else if (con_size_in_bytes <= threshold) {
151 // use explicit null stores
152 // code size = 2 + 3*n bytes (n = number of fields to clear)
153 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
154 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
155 movptr(Address(obj, i), t1_zero);
156 } else if (con_size_in_bytes > hdr_size_in_bytes) {
157 // use loop to null out the fields
158 // code size = 16 bytes for even n (n = number of fields to clear)
159 // initialize last object field first if odd number of fields
160 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
161 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
162 // initialize last object field if constant size is odd
163 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
164 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
165 // initialize remaining object fields: rdx is a multiple of 2
166 { Label loop;
167 bind(loop);
168 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)),
169 t1_zero);
170 decrement(index);
171 jcc(Assembler::notZero, loop);
172 }
173 }
174 }
175
176 if (CURRENT_ENV->dtrace_alloc_probes()) {
177 assert(obj == rax, "must be");
178 call(RuntimeAddress(Runtime1::entry_for(StubId::c1_dtrace_object_alloc_id)));
179 }
180
181 verify_oop(obj);
182 }
183
184 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, bool zero_array) {
185 assert(obj == rax, "obj must be in rax, for cmpxchg");
186 assert_different_registers(obj, len, t1, t2, klass);
187
188 // determine alignment mask
189 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
190
191 // check for negative or excessive length
192 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length));
193 jcc(Assembler::above, slow_case);
194
195 const Register arr_size = t2; // okay to be the same
196 // align object end
197 movptr(arr_size, base_offset_in_bytes + MinObjAlignmentInBytesMask);
198 lea(arr_size, Address(arr_size, len, f));
199 andptr(arr_size, ~MinObjAlignmentInBytesMask);
200
201 try_allocate(obj, arr_size, 0, t1, t2, slow_case);
202
203 initialize_header(obj, klass, len, t1, t2);
204
205 // clear rest of allocated space
206 if (zero_array) {
207 const Register len_zero = len;
208 // Align-up to word boundary, because we clear the 4 bytes potentially
209 // following the length field in initialize_header().
210 int base_offset = align_up(base_offset_in_bytes, BytesPerWord);
211 initialize_body(obj, arr_size, base_offset, len_zero);
212 }
213
214 if (CURRENT_ENV->dtrace_alloc_probes()) {
215 assert(obj == rax, "must be");
216 call(RuntimeAddress(Runtime1::entry_for(StubId::c1_dtrace_object_alloc_id)));
217 }
218
219 verify_oop(obj);
220 }
221
222 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) {
223 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
224 // Make sure there is enough stack space for this method's activation.
225 // Note that we do this before doing an enter(). This matches the
226 // ordering of C2's stack overflow check / rsp decrement and allows
227 // the SharedRuntime stack overflow handling to be consistent
228 // between the two compilers.
229 generate_stack_overflow_check(bang_size_in_bytes);
230
231 push(rbp);
232 if (PreserveFramePointer) {
233 mov(rbp, rsp);
234 }
235 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0
236
237 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
238 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
239 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */);
240 }
241
242
243 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) {
244 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0
245 pop(rbp);
246 }
247
248
249 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
250 if (breakAtEntry) int3();
251 // build frame
252 }
253
254 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
255 // rbp, + 0: link
256 // + 1: return address
257 // + 2: argument with offset 0
258 // + 3: argument with offset 1
259 // + 4: ...
260
261 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
262 }
263
264 #ifndef PRODUCT
265
266 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
267 if (!VerifyOops) return;
268 verify_oop_addr(Address(rsp, stack_offset));
269 }
270
271 void C1_MacroAssembler::verify_not_null_oop(Register r) {
272 if (!VerifyOops) return;
273 Label not_null;
274 testptr(r, r);
275 jcc(Assembler::notZero, not_null);
276 stop("non-null oop required");
277 bind(not_null);
278 verify_oop(r);
279 }
280
281 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
282 #ifdef ASSERT
283 if (inv_rax) movptr(rax, 0xDEAD);
284 if (inv_rbx) movptr(rbx, 0xDEAD);
285 if (inv_rcx) movptr(rcx, 0xDEAD);
286 if (inv_rdx) movptr(rdx, 0xDEAD);
287 if (inv_rsi) movptr(rsi, 0xDEAD);
288 if (inv_rdi) movptr(rdi, 0xDEAD);
289 #endif
290 }
291
292 #endif // ifndef PRODUCT