< prev index next > src/hotspot/cpu/aarch64/gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.cpp
Print this page
#include "gc/shenandoah/mode/shenandoahMode.hpp"
#include "gc/shenandoah/shenandoahBarrierSet.hpp"
#include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.hpp"
+ #include "gc/shenandoah/shenandoahNMethod.inline.hpp"
#include "gc/shenandoah/shenandoahRuntime.hpp"
#include "gc/shenandoah/shenandoahThreadLocalData.hpp"
#include "interpreter/interp_masm.hpp"
#include "interpreter/interpreter.hpp"
+ #include "nativeInst_aarch64.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/sharedRuntime.hpp"
#ifdef COMPILER1
#include "c1/c1_LIRAssembler.hpp"
#include "c1/c1_MacroAssembler.hpp"
__ bind(L_done);
}
#undef __
+ address ShenandoahBarrierSetAssembler::parse_jump_address(address pc) {
+ NativeInstruction* ni = nativeInstruction_at(pc);
+ assert(ni->is_jump(), "Initial code version: GC barrier fastpath must be a jump");
+ NativeJump* jmp = nativeJump_at(pc);
+ return jmp->jump_destination();
+ }
+
+ static uint32_t encode_patchable_nop() {
+ return 0xD503201F;
+ }
+
+ static uint32_t encode_patchable_jump(address pc, address target_pc) {
+ int32_t disp = checked_cast<int32_t>((intptr_t)target_pc - (intptr_t)pc);
+ int64_t imm26 = disp >> 2;
+ guarantee(Assembler::is_simm(imm26, 26), "Maximum offset is 128MiB");
+ return 0x14000000 | (imm26 & 0x03FFFFFF);
+ }
+
+ void ShenandoahBarrierSetAssembler::insert_patchable_nop(address pc) {
+ *((uint32_t*)pc) = encode_patchable_nop();
+ assert(nativeInstruction_at(pc)->is_nop(), "Sanity");
+ }
+
+ void ShenandoahBarrierSetAssembler::insert_patchable_jump(address pc, address target_pc) {
+ *((uint32_t*)pc) = encode_patchable_jump(pc, target_pc);
+ }
+
+ bool ShenandoahBarrierSetAssembler::is_patchable_nop(address pc) {
+ return *((uint32_t*)pc) == encode_patchable_nop();
+ }
+
+ bool ShenandoahBarrierSetAssembler::is_patchable_jump(address pc, address target_pc) {
+ return *((uint32_t*)pc) == encode_patchable_jump(pc, target_pc);
+ }
+
#ifdef COMPILER1
#define __ ce->masm()->
void ShenandoahBarrierSetAssembler::keepalive_barrier_c1_stub(LIR_Assembler* ce, ShenandoahKeepaliveBarrierStub* stub) {
} else {
__ strb(zr, Address(tmp2));
}
}
- void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp) {
- Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
+ void ShenandoahBarrierStubC2::patchable_jump(MacroAssembler& masm, const char gc_state, bool jump_when_state, Register tmp1, Register tmp2, Label* L_target) {
+ const size_t check_size = 8;
+
PhaseOutput* const output = Compile::current()->output();
- Address gc_state_fast(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(test_state)));
+ if (output->in_scratch_emit_size()) {
+ // Avoid binding L_target and emitting more branches in scratch emits.
+ // We know the patched check is exactly 1 instruction long in release,
+ // and verification adds more instructions.
+ for (size_t c = 0; c < 1 DEBUG_ONLY(+ check_size); c++) {
+ __ nop();
+ }
+ return;
+ }
- // We piggyback on scratch_emit_size mode to compute the slowpath stub size.
- // We'll use that information to decide whether we need a far jump to the
- // stub entry point or not. In scratch_emit_size mode we don't bind entry()
- // because otherwise it will be rebound when we later emit the instructions
- // for real.
- if (_needs_far_jump) {
- __ ldrb(tmp, gc_state_fast);
- __ cbz(tmp, *continuation());
- __ b(output->in_scratch_emit_size() ? *continuation() : *entry());
+ #ifdef ASSERT
+ Label L_fake_entry, L_skip;
+ Address gc_state_addr(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_offset()));
+
+ address check_start = __ pc();
+
+ __ ldrb(tmp1, gc_state_addr);
+ __ mov(tmp2, gc_state);
+ __ andr(tmp2, tmp1, tmp2);
+
+ // Emit the secondary jump and use it to cross-check against the actual GC state.
+ // This also checks that all interesting GC state transitions are done non-racily
+ // from the perspective of the thread executing the nmethod.
+ __ relocate(patchable_barrier_Relocation::spec(ShenandoahNMethod::encode_to_reloc(gc_state, jump_when_state)));
+ __ b(L_fake_entry);
+
+ // Currently hot-patched to NOP.
+ if (jump_when_state) {
+ __ cbz(tmp2, L_skip);
} else {
- __ ldrb(tmp, gc_state_fast);
- __ cbnz(tmp, output->in_scratch_emit_size() ? *continuation() : *entry());
+ __ cbnz(tmp2, L_skip);
}
+ __ hlt(0);
- // This is were the slowpath stub will return to or the code above will
- // jump to if the checks are false
+ // Currently hot-patched to JUMP.
+ __ bind(L_fake_entry);
+ if (jump_when_state) {
+ __ cbnz(tmp2, L_skip);
+ } else {
+ __ cbz(tmp2, L_skip);
+ }
+ __ hlt(0);
+
+ __ bind(L_skip);
+
+ address check_end = __ pc();
+ size_t actual_check_size = pointer_delta(check_end, check_start, Assembler::instruction_size);
+ assert(check_size == actual_check_size, "Must match: %zu != %zu", check_size, actual_check_size);
+ #endif
+
+ // Emit the unconditional branch in the first version of the method.
+ // Let the rest of runtime figure out how to manage it.
+ __ relocate(patchable_barrier_Relocation::spec(ShenandoahNMethod::encode_to_reloc(gc_state, jump_when_state)));
+ __ b(*L_target);
+ }
+
+ void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp1, Register tmp2) {
+ Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
+ patchable_jump_if_gc_state(masm, test_state, tmp1, tmp2, entry());
__ bind(*continuation());
}
void ShenandoahBarrierStubC2::emit_code(MacroAssembler& masm) {
Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
__ cbz(reg, *continuation());
}
}
void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Label* L_done) {
- Address gcstate(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::MARKING)));
Address index(rthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
Address buffer(rthread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
Label L_through, L_slowpath;
- // If another barrier is enabled as well, do a runtime check for a specific barrier.
+ // If another barrier is enabled as well, do a check for a specific barrier.
if (_needs_load_ref_barrier) {
- assert(L_done == nullptr, "L_done is always null when _needs_load_ref_barrier is true");
- __ ldrb(_tmp1, gcstate);
- __ cbz(_tmp1, L_through);
+ assert(L_done == nullptr, "Should be");
+ char state_to_check = ShenandoahHeap::MARKING;
+ patchable_jump_if_not_gc_state(masm, state_to_check, _tmp1, _tmp2, &L_through);
}
// Fast-path: put object into buffer.
// If buffer is already full, go slow.
__ ldr(_tmp1, index);
}
void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm) {
Label L_slow;
- // If another barrier is enabled as well, do a runtime check for a specific barrier.
+ // If another barrier is enabled as well, do a check for a specific barrier.
if (_needs_keep_alive_barrier) {
char state_to_check = ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0);
- Address gc_state_fast(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(state_to_check)));
- __ ldrb(_tmp1, gc_state_fast);
- maybe_far_jump_if_zero(masm, _tmp1);
+ patchable_jump_if_not_gc_state(masm, state_to_check, _tmp1, _tmp2, continuation());
}
// If weak references are being processed, weak/phantom loads need to go slow,
// regardless of their cset status.
if (_needs_load_ref_weak_barrier) {
- Address gc_state_fast(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::WEAK_ROOTS)));
- __ ldrb(_tmp1, gc_state_fast);
- __ cbnz(_tmp1, L_slow);
+ char state_to_check = ShenandoahHeap::WEAK_ROOTS;
+ patchable_jump_if_gc_state(masm, state_to_check, _tmp1, _tmp2, &L_slow);
}
// Cset-check. Fall-through to slow if in collection set.
bool is_aot = AOTCodeCache::is_on_for_dump();
if (!is_aot) {
< prev index next >