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/*
- * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2014, 2021, Red Hat Inc. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
- #include <sys/types.h>
-
#include "precompiled.hpp"
#include "jvm.h"
#include "asm/assembler.hpp"
#include "asm/assembler.inline.hpp"
#include "ci/ciEnv.hpp"
#include "oops/klass.inline.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/icache.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/jniHandles.inline.hpp"
+ #include "runtime/objectMonitor.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "runtime/thread.hpp"
+ #include "utilities/globalDefinitions.hpp"
#include "utilities/powerOfTwo.hpp"
#ifdef COMPILER1
#include "c1/c1_LIRAssembler.hpp"
#endif
#ifdef COMPILER2
#include "opto/compile.hpp"
#include "opto/node.hpp"
#include "opto/output.hpp"
#endif
+ #include <sys/types.h>
+
#ifdef PRODUCT
#define BLOCK_COMMENT(str) /* nothing */
#else
#define BLOCK_COMMENT(str) block_comment(str)
#endif
BLOCK_COMMENT("cmpxchg {");
if (UseLSE) {
mov(result, expected);
lse_cas(result, new_val, addr, size, acquire, release, /*not_pair*/ true);
compare_eq(result, expected, size);
+ #ifdef ASSERT
+ // Poison rscratch1 which is written on !UseLSE branch
+ mov(rscratch1, 0x1f1f1f1f1f1f1f1f);
+ #endif
} else {
Label retry_load, done;
if ((VM_Version::features() & VM_Version::CPU_STXR_PREFETCH))
prfm(Address(addr), PSTL1STRM);
bind(retry_load);
ldr(holder, Address(method, Method::const_offset())); // ConstMethod*
ldr(holder, Address(holder, ConstMethod::constants_offset())); // ConstantPool*
ldr(holder, Address(holder, ConstantPool::pool_holder_offset_in_bytes())); // InstanceKlass*
}
- void MacroAssembler::load_klass(Register dst, Register src) {
- if (UseCompressedClassPointers) {
+ // Loads the obj's Klass* into dst.
+ // src and dst must be distinct registers
+ // Preserves all registers (incl src, rscratch1 and rscratch2), but clobbers condition flags
+ void MacroAssembler::load_nklass(Register dst, Register src) {
+ assert(UseCompressedClassPointers, "expects UseCompressedClassPointers");
+
+ if (!UseCompactObjectHeaders) {
ldrw(dst, Address(src, oopDesc::klass_offset_in_bytes()));
+ return;
+ }
+
+ Label fast;
+
+ // Check if we can take the (common) fast path, if obj is unlocked.
+ ldr(dst, Address(src, oopDesc::mark_offset_in_bytes()));
+ tbz(dst, exact_log2(markWord::monitor_value), fast);
+
+ // Fetch displaced header
+ ldr(dst, Address(dst, OM_OFFSET_NO_MONITOR_VALUE_TAG(header)));
+
+ // Fast-path: shift and decode Klass*.
+ bind(fast);
+ lsr(dst, dst, markWord::klass_shift);
+ }
+
+ void MacroAssembler::load_klass(Register dst, Register src, bool null_check_src) {
+ if (null_check_src) {
+ if (UseCompactObjectHeaders) {
+ null_check(src, oopDesc::mark_offset_in_bytes());
+ } else {
+ null_check(src, oopDesc::klass_offset_in_bytes());
+ }
+ }
+
+ if (UseCompressedClassPointers) {
+ if (UseCompactObjectHeaders) {
+ load_nklass(dst, src);
+ } else {
+ ldrw(dst, Address(src, oopDesc::klass_offset_in_bytes()));
+ }
decode_klass_not_null(dst);
} else {
ldr(dst, Address(src, oopDesc::klass_offset_in_bytes()));
}
}
ldr(dst, Address(dst, mirror_offset));
resolve_oop_handle(dst, tmp);
}
void MacroAssembler::cmp_klass(Register oop, Register trial_klass, Register tmp) {
+ assert_different_registers(oop, trial_klass, tmp);
if (UseCompressedClassPointers) {
- ldrw(tmp, Address(oop, oopDesc::klass_offset_in_bytes()));
+ if (UseCompactObjectHeaders) {
+ load_nklass(tmp, oop);
+ } else {
+ ldrw(tmp, Address(oop, oopDesc::klass_offset_in_bytes()));
+ }
if (CompressedKlassPointers::base() == NULL) {
cmp(trial_klass, tmp, LSL, CompressedKlassPointers::shift());
return;
} else if (((uint64_t)CompressedKlassPointers::base() & 0xffffffff) == 0
&& CompressedKlassPointers::shift() == 0) {
ldr(tmp, Address(oop, oopDesc::klass_offset_in_bytes()));
}
cmp(trial_klass, tmp);
}
- void MacroAssembler::load_prototype_header(Register dst, Register src) {
- load_klass(dst, src);
- ldr(dst, Address(dst, Klass::prototype_header_offset()));
- }
-
void MacroAssembler::store_klass(Register dst, Register src) {
// FIXME: Should this be a store release? concurrent gcs assumes
// klass length is valid if klass field is not null.
if (UseCompressedClassPointers) {
encode_klass_not_null(src);
// Store to klass gap in destination
strw(src, Address(dst, oopDesc::klass_gap_offset_in_bytes()));
}
}
+ void MacroAssembler::load_prototype_header(Register dst, Register src) {
+ load_klass(dst, src);
+ ldr(dst, Address(dst, Klass::prototype_header_offset()));
+ }
+
// Algorithm must match CompressedOops::encode.
void MacroAssembler::encode_heap_oop(Register d, Register s) {
#ifdef ASSERT
verify_heapbase("MacroAssembler::encode_heap_oop: heap base corrupted?");
#endif
default:
ShouldNotReachHere();
}
}
}
+
+ // Implements lightweight-locking.
+ //
+ // - obj: the object to be locked
+ // - t1, t2, t3: temporary registers, will be destroyed
+ // - slow: branched to if locking fails, absolute offset may larger than 32KB (imm14 encoding).
+ void MacroAssembler::lightweight_lock(Register obj, Register t1, Register t2, Register t3, Label& slow) {
+ assert(LockingMode == LM_LIGHTWEIGHT, "only used with new lightweight locking");
+ assert_different_registers(obj, t1, t2, t3, rscratch1);
+
+ Label push;
+ const Register top = t1;
+ const Register mark = t2;
+ const Register t = t3;
+
+ // Preload the markWord. It is important that this is the first
+ // instruction emitted as it is part of C1's null check semantics.
+ ldr(mark, Address(obj, oopDesc::mark_offset_in_bytes()));
+
+ // Check if the lock-stack is full.
+ ldrw(top, Address(rthread, JavaThread::lock_stack_top_offset()));
+ cmpw(top, (unsigned)LockStack::end_offset());
+ br(Assembler::GE, slow);
+
+ // Check for recursion.
+ subw(t, top, oopSize);
+ ldr(t, Address(rthread, t));
+ cmp(obj, t);
+ br(Assembler::EQ, push);
+
+ // Check header for monitor (0b10).
+ tst(mark, markWord::monitor_value);
+ br(Assembler::NE, slow);
+
+ // Try to lock. Transition lock bits 0b01 => 0b00
+ assert(oopDesc::mark_offset_in_bytes() == 0, "required to avoid lea");
+ orr(mark, mark, markWord::unlocked_value);
+ eor(t, mark, markWord::unlocked_value);
+ cmpxchg(/*addr*/ obj, /*expected*/ mark, /*new*/ t, Assembler::xword,
+ /*acquire*/ true, /*release*/ false, /*weak*/ false, noreg);
+ br(Assembler::NE, slow);
+
+ bind(push);
+ // After successful lock, push object on lock-stack.
+ str(obj, Address(rthread, top));
+ addw(top, top, oopSize);
+ strw(top, Address(rthread, JavaThread::lock_stack_top_offset()));
+ }
+
+ // Implements lightweight-unlocking.
+ //
+ // - obj: the object to be unlocked
+ // - t1, t2, t3: temporary registers
+ // - slow: branched to if unlocking fails, absolute offset may larger than 32KB (imm14 encoding).
+ void MacroAssembler::lightweight_unlock(Register obj, Register t1, Register t2, Register t3, Label& slow) {
+ assert(LockingMode == LM_LIGHTWEIGHT, "only used with new lightweight locking");
+ // cmpxchg clobbers rscratch1.
+ assert_different_registers(obj, t1, t2, t3, rscratch1);
+
+ #ifdef ASSERT
+ {
+ // Check for lock-stack underflow.
+ Label stack_ok;
+ ldrw(t1, Address(rthread, JavaThread::lock_stack_top_offset()));
+ cmpw(t1, (unsigned)LockStack::start_offset());
+ br(Assembler::GE, stack_ok);
+ STOP("Lock-stack underflow");
+ bind(stack_ok);
+ }
+ #endif
+
+ Label unlocked, push_and_slow;
+ const Register top = t1;
+ const Register mark = t2;
+ const Register t = t3;
+
+ // Check if obj is top of lock-stack.
+ ldrw(top, Address(rthread, JavaThread::lock_stack_top_offset()));
+ subw(top, top, oopSize);
+ ldr(t, Address(rthread, top));
+ cmp(obj, t);
+ br(Assembler::NE, slow);
+
+ // Pop lock-stack.
+ DEBUG_ONLY(str(zr, Address(rthread, top));)
+ strw(top, Address(rthread, JavaThread::lock_stack_top_offset()));
+
+ // Check if recursive.
+ subw(t, top, oopSize);
+ ldr(t, Address(rthread, t));
+ cmp(obj, t);
+ br(Assembler::EQ, unlocked);
+
+ // Not recursive. Check header for monitor (0b10).
+ ldr(mark, Address(obj, oopDesc::mark_offset_in_bytes()));
+ tbnz(mark, log2i_exact(markWord::monitor_value), push_and_slow);
+
+ #ifdef ASSERT
+ // Check header not unlocked (0b01).
+ Label not_unlocked;
+ tbz(mark, log2i_exact(markWord::unlocked_value), not_unlocked);
+ stop("lightweight_unlock already unlocked");
+ bind(not_unlocked);
+ #endif
+
+ // Try to unlock. Transition lock bits 0b00 => 0b01
+ assert(oopDesc::mark_offset_in_bytes() == 0, "required to avoid lea");
+ orr(t, mark, markWord::unlocked_value);
+ cmpxchg(obj, mark, t, Assembler::xword,
+ /*acquire*/ false, /*release*/ true, /*weak*/ false, noreg);
+ br(Assembler::EQ, unlocked);
+
+ bind(push_and_slow);
+ // Restore lock-stack and handle the unlock in runtime.
+ DEBUG_ONLY(str(obj, Address(rthread, top));)
+ addw(top, top, oopSize);
+ strw(top, Address(rthread, JavaThread::lock_stack_top_offset()));
+ b(slow);
+
+ bind(unlocked);
+ }
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