1 /*
2 * Copyright (c) 1999, 2025, 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/frame.inline.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 (LockingMode == LM_LIGHTWEIGHT) {
60 lightweight_lock(disp_hdr, obj, hdr, tmp, slow_case);
61 } else if (LockingMode == LM_LEGACY) {
62 Label done;
63
64 if (DiagnoseSyncOnValueBasedClasses != 0) {
65 load_klass(hdr, obj, rscratch1);
66 testb(Address(hdr, Klass::misc_flags_offset()), KlassFlags::_misc_is_value_based_class);
67 jcc(Assembler::notZero, slow_case);
68 }
69
70 // Load object header
71 movptr(hdr, Address(obj, hdr_offset));
72 // and mark it as unlocked
73 orptr(hdr, markWord::unlocked_value);
74 if (EnableValhalla) {
75 // Mask inline_type bit such that we go to the slow path if object is an inline type
76 andptr(hdr, ~((int) markWord::inline_type_bit_in_place));
77 }
78 // save unlocked object header into the displaced header location on the stack
79 movptr(Address(disp_hdr, 0), hdr);
80 // test if object header is still the same (i.e. unlocked), and if so, store the
81 // displaced header address in the object header - if it is not the same, get the
82 // object header instead
83 MacroAssembler::lock(); // must be immediately before cmpxchg!
84 cmpxchgptr(disp_hdr, Address(obj, hdr_offset));
85 // if the object header was the same, we're done
86 jcc(Assembler::equal, done);
87 // if the object header was not the same, it is now in the hdr register
88 // => test if it is a stack pointer into the same stack (recursive locking), i.e.:
89 //
90 // 1) (hdr & aligned_mask) == 0
91 // 2) rsp <= hdr
92 // 3) hdr <= rsp + page_size
93 //
94 // these 3 tests can be done by evaluating the following expression:
95 //
96 // (hdr - rsp) & (aligned_mask - page_size)
97 //
98 // assuming both the stack pointer and page_size have their least
99 // significant 2 bits cleared and page_size is a power of 2
100 subptr(hdr, rsp);
101 andptr(hdr, aligned_mask - (int)os::vm_page_size());
102 // for recursive locking, the result is zero => save it in the displaced header
103 // location (null in the displaced hdr location indicates recursive locking)
104 movptr(Address(disp_hdr, 0), hdr);
105 // otherwise we don't care about the result and handle locking via runtime call
106 jcc(Assembler::notZero, slow_case);
107 // done
108 bind(done);
109 inc_held_monitor_count();
110 }
111
112 return null_check_offset;
113 }
114
115 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
116 const int aligned_mask = BytesPerWord -1;
117 const int hdr_offset = oopDesc::mark_offset_in_bytes();
118 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
119 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
120 Label done;
121
122 if (LockingMode != LM_LIGHTWEIGHT) {
123 // load displaced header
124 movptr(hdr, Address(disp_hdr, 0));
125 // if the loaded hdr is null we had recursive locking
126 testptr(hdr, hdr);
127 // if we had recursive locking, we are done
128 jcc(Assembler::zero, done);
129 }
130
131 // load object
132 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset()));
133 verify_oop(obj);
134
135 if (LockingMode == LM_LIGHTWEIGHT) {
136 lightweight_unlock(obj, disp_hdr, hdr, slow_case);
137 } else if (LockingMode == LM_LEGACY) {
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 MacroAssembler::lock(); // must be immediately before cmpxchg!
142 cmpxchgptr(hdr, Address(obj, hdr_offset));
143 // if the object header was not pointing to the displaced header,
144 // we do unlocking via runtime call
145 jcc(Assembler::notEqual, slow_case);
146 // done
147 bind(done);
148 dec_held_monitor_count();
149 }
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 jmp(slow_case);
159 }
160 }
161
162
163 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
164 assert_different_registers(obj, klass, len, t1, t2);
165 if (UseCompactObjectHeaders || EnableValhalla) {
166 movptr(t1, Address(klass, Klass::prototype_header_offset()));
167 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), t1);
168 } else {
169 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value()));
170 }
171 if (UseCompressedClassPointers) { // Take care not to kill klass
172 movptr(t1, klass);
173 encode_klass_not_null(t1, rscratch1);
174 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1);
175 } else if (!UseCompactObjectHeaders) {
176 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass);
177 }
178
179 if (len->is_valid()) {
180 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len);
181 int base_offset = arrayOopDesc::length_offset_in_bytes() + BytesPerInt;
182 if (!is_aligned(base_offset, BytesPerWord)) {
183 assert(is_aligned(base_offset, BytesPerInt), "must be 4-byte aligned");
184 // Clear gap/first 4 bytes following the length field.
185 xorl(t1, t1);
186 movl(Address(obj, base_offset), t1);
187 }
188 } else if (UseCompressedClassPointers && !UseCompactObjectHeaders) {
189 xorptr(t1, t1);
190 store_klass_gap(obj, t1);
191 }
192 }
193
194
195 // preserves obj, destroys len_in_bytes
196 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) {
197 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0");
198 Label done;
199
200 // len_in_bytes is positive and ptr sized
201 subptr(len_in_bytes, hdr_size_in_bytes);
202 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1);
203 bind(done);
204 }
205
206
207 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) {
208 assert(obj == rax, "obj must be in rax, for cmpxchg");
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 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) {
218 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0,
219 "con_size_in_bytes is not multiple of alignment");
220 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize;
221 if (UseCompactObjectHeaders) {
222 assert(hdr_size_in_bytes == 8, "check object headers size");
223 }
224 initialize_header(obj, klass, noreg, t1, t2);
225
226 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) {
227 // clear rest of allocated space
228 const Register t1_zero = t1;
229 const Register index = t2;
230 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below)
231 if (var_size_in_bytes != noreg) {
232 mov(index, var_size_in_bytes);
233 initialize_body(obj, index, hdr_size_in_bytes, t1_zero);
234 } else if (con_size_in_bytes <= threshold) {
235 // use explicit null stores
236 // code size = 2 + 3*n bytes (n = number of fields to clear)
237 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
238 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord)
239 movptr(Address(obj, i), t1_zero);
240 } else if (con_size_in_bytes > hdr_size_in_bytes) {
241 // use loop to null out the fields
242 // code size = 16 bytes for even n (n = number of fields to clear)
243 // initialize last object field first if odd number of fields
244 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code)
245 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3);
246 // initialize last object field if constant size is odd
247 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0)
248 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero);
249 // initialize remaining object fields: rdx is a multiple of 2
250 { Label loop;
251 bind(loop);
252 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*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(C1StubId::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, bool zero_array) {
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, 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 if (zero_array) {
291 const Register len_zero = len;
292 // Align-up to word boundary, because we clear the 4 bytes potentially
293 // following the length field in initialize_header().
294 int base_offset = align_up(base_offset_in_bytes, BytesPerWord);
295 initialize_body(obj, arr_size, base_offset, len_zero);
296 }
297
298 if (CURRENT_ENV->dtrace_alloc_probes()) {
299 assert(obj == rax, "must be");
300 call(RuntimeAddress(Runtime1::entry_for(C1StubId::dtrace_object_alloc_id)));
301 }
302
303 verify_oop(obj);
304 }
305
306 void C1_MacroAssembler::build_frame_helper(int frame_size_in_bytes, int sp_offset_for_orig_pc, int sp_inc, bool reset_orig_pc, bool needs_stack_repair) {
307 push(rbp);
308 if (PreserveFramePointer) {
309 mov(rbp, rsp);
310 }
311 decrement(rsp, frame_size_in_bytes);
312
313 if (needs_stack_repair) {
314 // Save stack increment (also account for fixed framesize and rbp)
315 assert((sp_inc & (StackAlignmentInBytes-1)) == 0, "stack increment not aligned");
316 int real_frame_size = sp_inc + frame_size_in_bytes + wordSize;
317 movptr(Address(rsp, frame_size_in_bytes - wordSize), real_frame_size);
318 }
319 if (reset_orig_pc) {
320 // Zero orig_pc to detect deoptimization during buffering in the entry points
321 movptr(Address(rsp, sp_offset_for_orig_pc), 0);
322 }
323 }
324
325 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes, int sp_offset_for_orig_pc, bool needs_stack_repair, bool has_scalarized_args, Label* verified_inline_entry_label) {
326 // Make sure there is enough stack space for this method's activation.
327 // Note that we do this before doing an enter(). This matches the
328 // ordering of C2's stack overflow check / rsp decrement and allows
329 // the SharedRuntime stack overflow handling to be consistent
330 // between the two compilers.
331 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
332 generate_stack_overflow_check(bang_size_in_bytes);
333
334 build_frame_helper(frame_size_in_bytes, sp_offset_for_orig_pc, 0, has_scalarized_args, needs_stack_repair);
335
336 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
337 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
338 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */);
339
340 if (verified_inline_entry_label != nullptr) {
341 // Jump here from the scalarized entry points that already created the frame.
342 bind(*verified_inline_entry_label);
343 }
344 }
345
346 void C1_MacroAssembler::verified_entry(bool breakAtEntry) {
347 if (breakAtEntry) {
348 // Verified Entry first instruction should be 5 bytes long for correct
349 // patching by patch_verified_entry().
350 //
351 // Breakpoint has one byte first instruction.
352 // Also first instruction will be one byte "push(rbp)" if stack banging
353 // code is not generated (see build_frame() above).
354 // For all these cases generate long instruction first.
355 fat_nop();
356 }
357 if (breakAtEntry) int3();
358 // build frame
359 }
360
361 int C1_MacroAssembler::scalarized_entry(const CompiledEntrySignature* ces, int frame_size_in_bytes, int bang_size_in_bytes, int sp_offset_for_orig_pc, Label& verified_inline_entry_label, bool is_inline_ro_entry) {
362 assert(InlineTypePassFieldsAsArgs, "sanity");
363 // Make sure there is enough stack space for this method's activation.
364 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect");
365 generate_stack_overflow_check(bang_size_in_bytes);
366
367 GrowableArray<SigEntry>* sig = ces->sig();
368 GrowableArray<SigEntry>* sig_cc = is_inline_ro_entry ? ces->sig_cc_ro() : ces->sig_cc();
369 VMRegPair* regs = ces->regs();
370 VMRegPair* regs_cc = is_inline_ro_entry ? ces->regs_cc_ro() : ces->regs_cc();
371 int args_on_stack = ces->args_on_stack();
372 int args_on_stack_cc = is_inline_ro_entry ? ces->args_on_stack_cc_ro() : ces->args_on_stack_cc();
373
374 assert(sig->length() <= sig_cc->length(), "Zero-sized inline class not allowed!");
375 BasicType* sig_bt = NEW_RESOURCE_ARRAY(BasicType, sig_cc->length());
376 int args_passed = sig->length();
377 int args_passed_cc = SigEntry::fill_sig_bt(sig_cc, sig_bt);
378
379 // Create a temp frame so we can call into the runtime. It must be properly set up to accommodate GC.
380 build_frame_helper(frame_size_in_bytes, sp_offset_for_orig_pc, 0, true, ces->c1_needs_stack_repair());
381
382 // The runtime call might safepoint, make sure nmethod entry barrier is executed
383 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
384 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub
385 bs->nmethod_entry_barrier(this, nullptr /* slow_path */, nullptr /* continuation */);
386
387 // FIXME -- call runtime only if we cannot in-line allocate all the incoming inline type args.
388 movptr(rbx, (intptr_t)(ces->method()));
389 if (is_inline_ro_entry) {
390 call(RuntimeAddress(Runtime1::entry_for(C1StubId::buffer_inline_args_no_receiver_id)));
391 } else {
392 call(RuntimeAddress(Runtime1::entry_for(C1StubId::buffer_inline_args_id)));
393 }
394 int rt_call_offset = offset();
395
396 // Remove the temp frame
397 addptr(rsp, frame_size_in_bytes);
398 pop(rbp);
399
400 // Check if we need to extend the stack for packing
401 int sp_inc = 0;
402 if (args_on_stack > args_on_stack_cc) {
403 sp_inc = extend_stack_for_inline_args(args_on_stack);
404 }
405
406 shuffle_inline_args(true, is_inline_ro_entry, sig_cc,
407 args_passed_cc, args_on_stack_cc, regs_cc, // from
408 args_passed, args_on_stack, regs, // to
409 sp_inc, rax);
410
411 // Create the real frame. Below jump will then skip over the stack banging and frame
412 // setup code in the verified_inline_entry (which has a different real_frame_size).
413 build_frame_helper(frame_size_in_bytes, sp_offset_for_orig_pc, sp_inc, false, ces->c1_needs_stack_repair());
414
415 jmp(verified_inline_entry_label);
416 return rt_call_offset;
417 }
418
419 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) {
420 // rbp, + 0: link
421 // + 1: return address
422 // + 2: argument with offset 0
423 // + 3: argument with offset 1
424 // + 4: ...
425
426 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord));
427 }
428
429 #ifndef PRODUCT
430
431 void C1_MacroAssembler::verify_stack_oop(int stack_offset) {
432 if (!VerifyOops) return;
433 verify_oop_addr(Address(rsp, stack_offset));
434 }
435
436 void C1_MacroAssembler::verify_not_null_oop(Register r) {
437 if (!VerifyOops) return;
438 Label not_null;
439 testptr(r, r);
440 jcc(Assembler::notZero, not_null);
441 stop("non-null oop required");
442 bind(not_null);
443 verify_oop(r);
444 }
445
446 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) {
447 #ifdef ASSERT
448 if (inv_rax) movptr(rax, 0xDEAD);
449 if (inv_rbx) movptr(rbx, 0xDEAD);
450 if (inv_rcx) movptr(rcx, 0xDEAD);
451 if (inv_rdx) movptr(rdx, 0xDEAD);
452 if (inv_rsi) movptr(rsi, 0xDEAD);
453 if (inv_rdi) movptr(rdi, 0xDEAD);
454 #endif
455 }
456
457 #endif // ifndef PRODUCT