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#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"
} else {
__ strb(zr, Address(tmp2));
}
}
+ void ShenandoahBarrierStubC2::patchable_jump_if_gc_state(MacroAssembler& masm, const char test_state, Label* L_target) {
+ // 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(test_state, false)));
+ __ b(*L_target);
+ }
+
+ void ShenandoahBarrierStubC2::patchable_jump_if_not_gc_state(MacroAssembler& masm, const char test_state, Label* L_target) {
+ // 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(test_state, true)));
+ __ b(*L_target);
+ }
+
void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp) {
Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
PhaseOutput* const output = Compile::current()->output();
- Address gc_state_fast(rthread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(test_state)));
- // 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());
+ if (output->in_scratch_emit_size()) {
+ // 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.
+ __ nop();
} else {
- __ ldrb(tmp, gc_state_fast);
- __ cbnz(tmp, output->in_scratch_emit_size() ? *continuation() : *entry());
+ patchable_jump_if_gc_state(masm, test_state, entry());
}
// This is were the slowpath stub will return to or the code above will
// jump to if the checks are false
__ bind(*continuation());
}
+ address ShenandoahBarrierSetAssembler::parse_stub_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 bool is_patchable_nop(address pc) {
+ if (*(pc + 0) != 0x1F) return false;
+ if (*(pc + 1) != 0x20) return false;
+ if (*(pc + 2) != 0x03) return false;
+ if (*(pc + 3) != 0xD5) return false;
+ return true;
+ }
+
+ static void insert_patchable_nop(address pc) {
+ *reinterpret_cast<int32_t*>(pc) = 0xD503201F;
+ }
+
+ static void insert_patchable_jump(address code_pos, address entry) {
+ intptr_t disp = (intptr_t)entry - ((intptr_t)code_pos);
+ int64_t imm26 = disp >> 2;
+ guarantee(Assembler::is_simm(imm26, 26), "maximum offset is 128MiB, requested %ld", imm26);
+
+ uint32_t new_val = 0x14000000 | (imm26 & 0x03FFFFFF);
+ AtomicAccess::store((uint32_t*)code_pos, new_val);
+ }
+
+ static void check_at(bool cond, address pc, const char* msg) {
+ assert(cond, "%s: at PC " PTR_FORMAT ": %02x%02x%02x%02x",
+ msg, p2i(pc), *(pc + 0), *(pc + 1), *(pc + 2), *(pc + 3));
+ }
+
+ bool ShenandoahBarrierSetAssembler::patch_branch_to_nop(address pc) {
+ NativeInstruction* ni = nativeInstruction_at(pc);
+ bool patching = ni->is_jump();
+ if (patching) {
+ insert_patchable_nop(pc);
+ }
+ check_at(is_patchable_nop(pc), pc, "Should be nop");
+ return patching;
+ }
+
+ bool ShenandoahBarrierSetAssembler::patch_nop_to_branch(address pc, address stub_addr) {
+ bool patching = is_patchable_nop(pc);
+ if (patching) {
+ insert_patchable_jump(pc, stub_addr);
+ }
+
+ NativeInstruction* ni = nativeInstruction_at(pc);
+ check_at(ni->is_jump(), pc, "Should be jump");
+ check_at(nativeJump_at(pc)->jump_destination() == stub_addr, pc, "Jump should be to the same address");
+ return patching;
+ }
+
void ShenandoahBarrierStubC2::emit_code(MacroAssembler& masm) {
Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
assert(_needs_keep_alive_barrier || _needs_load_ref_barrier, "Why are you here?");
PhaseOutput* const output = Compile::current()->output();
__ 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, &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, 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, &L_slow);
}
// Cset-check. Fall-through to slow if in collection set.
bool is_aot = AOTCodeCache::is_on_for_dump();
if (!is_aot) {
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