void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
const int aligned_mask = BytesPerWord -1;
const int hdr_offset = oopDesc::mark_offset_in_bytes();
assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction");
assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different");
Label done;
if (UseBiasedLocking) {
// load object
movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
biased_locking_exit(obj, hdr, done);
}
// load displaced header
movptr(hdr, Address(disp_hdr, 0));
// if the loaded hdr is NULL we had recursive locking
testptr(hdr, hdr);
// if we had recursive locking, we are done
jcc(Assembler::zero, done);
if (!UseBiasedLocking) {
// load object
movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
}
verify_oop(obj);
// test if object header is pointing to the displaced header, and if so, restore
// the displaced header in the object - if the object header is not pointing to
// the displaced header, get the object header instead
if (os::is_MP()) MacroAssembler::lock(); // must be immediately before cmpxchg!
cmpxchgptr(hdr, Address(obj, hdr_offset));
// if the object header was not pointing to the displaced header,
// we do unlocking via runtime call
jcc(Assembler::notEqual, slow_case);
// done
bind(done);
}
void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) {
const int aligned_mask = BytesPerWord -1;
const int hdr_offset = oopDesc::mark_offset_in_bytes();
assert_different_registers(hdr, obj, disp_hdr);
NearLabel done;
if (UseBiasedLocking) {
// Load object.
z_lg(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
biased_locking_exit(obj, hdr, done);
}
// Load displaced header.
z_ltg(hdr, Address(disp_hdr, (intptr_t)0));
// If the loaded hdr is NULL we had recursive locking, and we are done.
z_bre(done);
if (!UseBiasedLocking) {
// Load object.
z_lg(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()));
}
verify_oop(obj);
// Test if object header is pointing to the displaced header, and if so, restore
// the displaced header in the object. If the object header is not pointing to
// the displaced header, get the object header instead.
z_csg(disp_hdr, hdr, hdr_offset, obj);
// If the object header was not pointing to the displaced header,
// we do unlocking via runtime call.
branch_optimized(Assembler::bcondNotEqual, slow_case);
// done
bind(done);
}
void C1_MacroAssembler::unlock_object(Register Rmark, Register Roop, Register Rbox, Label& slow_case) {
assert_different_registers(Rmark, Roop, Rbox);
Label done;
Address mark_addr(Roop, oopDesc::mark_offset_in_bytes());
assert(mark_addr.disp() == 0, "cas must take a zero displacement");
if (UseBiasedLocking) {
// load the object out of the BasicObjectLock
ld_ptr(Rbox, BasicObjectLock::obj_offset_in_bytes(), Roop);
verify_oop(Roop);
biased_locking_exit(mark_addr, Rmark, done);
}
// Test first it it is a fast recursive unlock
ld_ptr(Rbox, BasicLock::displaced_header_offset_in_bytes(), Rmark);
br_null_short(Rmark, Assembler::pt, done);
if (!UseBiasedLocking) {
// load object
ld_ptr(Rbox, BasicObjectLock::obj_offset_in_bytes(), Roop);
verify_oop(Roop);
}
// Check if it is still a light weight lock, this is is true if we see
// the stack address of the basicLock in the markOop of the object
cas_ptr(mark_addr.base(), Rbox, Rmark);
cmp(Rbox, Rmark);
brx(Assembler::notEqual, false, Assembler::pn, slow_case);
delayed()->nop();
// Done
bind(done);
}
void C1_MacroAssembler::unlock_object(Register Rmark, Register Roop, Register Rbox, Label& slow_case) {
assert_different_registers(Rmark, Roop, Rbox);
Label slow_int, done;
Address mark_addr(Roop, oopDesc::mark_offset_in_bytes());
assert(mark_addr.disp() == 0, "cas must take a zero displacement");
if (UseBiasedLocking) {
// Load the object out of the BasicObjectLock.
ld(Roop, BasicObjectLock::obj_offset_in_bytes(), Rbox);
verify_oop(Roop);
biased_locking_exit(CCR0, Roop, R0, done);
}
// Test first it it is a fast recursive unlock.
ld(Rmark, BasicLock::displaced_header_offset_in_bytes(), Rbox);
cmpdi(CCR0, Rmark, 0);
beq(CCR0, done);
if (!UseBiasedLocking) {
// Load object.
ld(Roop, BasicObjectLock::obj_offset_in_bytes(), Rbox);
verify_oop(Roop);
}
// Check if it is still a light weight lock, this is is true if we see
// the stack address of the basicLock in the markOop of the object.
cmpxchgd(/*flag=*/CCR0,
/*current_value=*/R0,
/*compare_value=*/Rbox,
/*exchange_value=*/Rmark,
/*where=*/Roop,
MacroAssembler::MemBarRel,
MacroAssembler::cmpxchgx_hint_release_lock(),
noreg,
&slow_int);
b(done);
bind(slow_int);
b(slow_case); // far
// Done
bind(done);
}
