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8338379: Accesses to class init state should be properly synchronized #21110

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8338379: Accesses to class init state should be properly synchronized #21110

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66dc20b
Initial version
shipilev Sep 19, 2024
179d8aa
Relax to just a release
shipilev Sep 23, 2024
d34a669
Pick up PPC64 patch from Martin
shipilev Sep 30, 2024
a7895d9
Merge branch 'master' into JDK-8338379-class-init-checks
shipilev Sep 30, 2024
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2 changes: 1 addition & 1 deletion src/hotspot/cpu/ppc/c1_LIRAssembler_ppc.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2274,7 +2274,7 @@ void LIR_Assembler::emit_alloc_obj(LIR_OpAllocObj* op) {
}
__ lbz(op->tmp1()->as_register(),
in_bytes(InstanceKlass::init_state_offset()), op->klass()->as_register());
__ lwsync(); // acquire
// acquire barrier included in membar_storestore() which follows the allocation immediately.
__ cmpwi(CCR0, op->tmp1()->as_register(), InstanceKlass::fully_initialized);
__ bc_far_optimized(Assembler::bcondCRbiIs0, __ bi0(CCR0, Assembler::equal), *op->stub()->entry());
}
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9 changes: 6 additions & 3 deletions src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2410,7 +2410,7 @@ void MacroAssembler::verify_secondary_supers_table(Register r_sub_klass,
void MacroAssembler::clinit_barrier(Register klass, Register thread, Label* L_fast_path, Label* L_slow_path) {
assert(L_fast_path != nullptr || L_slow_path != nullptr, "at least one is required");

Label L_fallthrough;
Label L_check_thread, L_fallthrough;
if (L_fast_path == nullptr) {
L_fast_path = &L_fallthrough;
} else if (L_slow_path == nullptr) {
Expand All @@ -2419,11 +2419,14 @@ void MacroAssembler::clinit_barrier(Register klass, Register thread, Label* L_fa

// Fast path check: class is fully initialized
lbz(R0, in_bytes(InstanceKlass::init_state_offset()), klass);
lwsync(); // acquire
// acquire by cmp-branch-isync if fully_initialized
cmpwi(CCR0, R0, InstanceKlass::fully_initialized);
beq(CCR0, *L_fast_path);
bne(CCR0, L_check_thread);
isync();
b(*L_fast_path);

// Fast path check: current thread is initializer thread
bind(L_check_thread);
ld(R0, in_bytes(InstanceKlass::init_thread_offset()), klass);
cmpd(CCR0, thread, R0);
if (L_slow_path == &L_fallthrough) {
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