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8217874: Shenandoah: Clobbered register in ShenandoahBarrierSetAssembler::cmpxchg_oop()

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Reviewed-by: adinn
This commit is contained in:
Roman Kennke 2019-02-11 16:49:08 +01:00
parent 9bc10ee9bf
commit 7e1347391a
1 changed files with 21 additions and 19 deletions
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40
src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp
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@ -425,54 +425,56 @@ void ShenandoahBarrierSetAssembler::resolve(MacroAssembler* masm, DecoratorSet d
void ShenandoahBarrierSetAssembler::cmpxchg_oop(MacroAssembler* masm, Register addr, Register expected, Register new_val,
bool acquire, bool release, bool weak, bool is_cae,
Register result) {
Register tmp = rscratch2;
Register tmp1 = rscratch1;
Register tmp2 = rscratch2;
bool is_narrow = UseCompressedOops;
Assembler::operand_size size = is_narrow ? Assembler::word : Assembler::xword;
assert_different_registers(addr, expected, new_val, result, tmp);
assert_different_registers(addr, expected, new_val, tmp1, tmp2);
Label retry, done, fail;
// CAS, using LL/SC pair.
__ bind(retry);
__ load_exclusive(result, addr, size, acquire);
__ load_exclusive(tmp1, addr, size, acquire);
if (is_narrow) {
__ cmpw(result, expected);
__ cmpw(tmp1, expected);
} else {
__ cmp(result, expected);
__ cmp(tmp1, expected);
}
__ br(Assembler::NE, fail);
__ store_exclusive(tmp, new_val, addr, size, release);
__ store_exclusive(tmp2, new_val, addr, size, release);
if (weak) {
__ cmpw(tmp, 0u); // If the store fails, return NE to our caller
__ cmpw(tmp2, 0u); // If the store fails, return NE to our caller
} else {
__ cbnzw(tmp, retry);
__ cbnzw(tmp2, retry);
}
__ b(done);
__ bind(fail);
// Check if rb(expected)==rb(result)
// Check if rb(expected)==rb(tmp1)
// Shuffle registers so that we have memory value ready for next expected.
__ mov(tmp, expected);
__ mov(expected, result);
__ mov(tmp2, expected);
__ mov(expected, tmp1);
if (is_narrow) {
__ decode_heap_oop(result, result);
__ decode_heap_oop(tmp, tmp);
__ decode_heap_oop(tmp1, tmp1);
__ decode_heap_oop(tmp2, tmp2);
}
read_barrier_impl(masm, result);
read_barrier_impl(masm, tmp);
__ cmp(result, tmp);
read_barrier_impl(masm, tmp1);
read_barrier_impl(masm, tmp2);
__ cmp(tmp1, tmp2);
// Retry with expected now being the value we just loaded from addr.
__ br(Assembler::EQ, retry);
if (is_cae && is_narrow) {
// For cmp-and-exchange and narrow oops, we need to restore
// the compressed old-value. We moved it to 'expected' a few lines up.
__ mov(result, expected);
__ mov(tmp1, expected);
}
__ bind(done);
if (!is_cae) {
if (is_cae) {
__ mov(result, tmp1);
} else {
__ cset(result, Assembler::EQ);
}
}