< prev index next > src/hotspot/cpu/x86/gc/shenandoah/shenandoahBarrierSetAssembler_x86.cpp
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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/interpreter.hpp"
+ #include "nativeInst_x86.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/sharedRuntime.hpp"
#include "utilities/macros.hpp"
#ifdef COMPILER1
#include "c1/c1_LIRAssembler.hpp"
}
void ShenandoahBarrierStubC2::enter_if_gc_state(MacroAssembler& masm, const char test_state, Register tmp) {
Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
- Address gc_state_fast(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(test_state)));
- __ cmpb(gc_state_fast, 0);
- __ jcc(Assembler::notEqual, *entry());
+ // Emit the unconditional branch in the first version of the method.
+ // Let the rest of runtime figure out how to manage it.
+ __ relocate(barrier_Relocation::spec(), ShenandoahNMethod::gc_state_to_reloc(test_state));
+ __ jmp(*entry(), /* maybe_short = */ 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 void insert_5_byte_nop(address pc) {
+ *(pc + 0) = 0x0F;
+ *(pc + 1) = 0x1F;
+ *(pc + 2) = 0x44;
+ *(pc + 3) = 0x00;
+ *(pc + 4) = 0x00;
+ ICache::invalidate_range(pc, 5);
+ }
+
+ static bool is_5_byte_nop(address pc) {
+ if (*(pc + 0) != 0x0F) return false;
+ if (*(pc + 1) != 0x1F) return false;
+ if (*(pc + 2) != 0x44) return false;
+ if (*(pc + 3) != 0x00) return false;
+ if (*(pc + 4) != 0x00) return false;
+ return true;
+ }
+
+ static void check_at(bool cond, address pc, const char* msg) {
+ assert(cond, "%s: at PC " PTR_FORMAT ": %02x%02x%02x%02x%02x",
+ msg, p2i(pc), *(pc + 0), *(pc + 1), *(pc + 2), *(pc + 3), *(pc + 4));
+ }
+
+ bool ShenandoahBarrierSetAssembler::is_active(address pc) {
+ NativeInstruction* ni = nativeInstruction_at(pc);
+ return ni->is_jump();
+ }
+
+ void ShenandoahBarrierSetAssembler::patch_branch_to_nop(address pc) {
+ NativeInstruction* ni = nativeInstruction_at(pc);
+ if (ni->is_jump()) {
+ insert_5_byte_nop(pc);
+ } else {
+ check_at(is_5_byte_nop(pc), pc, "Should already be nop");
+ }
+ }
+
+ void ShenandoahBarrierSetAssembler::patch_nop_to_branch(address pc, address stub_addr) {
+ NativeInstruction* ni = nativeInstruction_at(pc);
+ if (is_5_byte_nop(pc)) {
+ NativeJump::insert(pc, stub_addr);
+ } else {
+ check_at(ni->is_jump(), pc, "Should already be jump");
+ check_at(nativeJump_at(pc)->jump_destination() == stub_addr, pc, "Jump should be to the same address");
+ }
+ }
+
void ShenandoahBarrierStubC2::emit_code(MacroAssembler& masm) {
Assembler::InlineSkippedInstructionsCounter skip_counter(&masm);
assert(_needs_keep_alive_barrier || _needs_load_ref_barrier, "Why are you here?");
// On x86, there is a significant penalty with unaligned branch target, for example
ShouldNotReachHere();
}
}
void ShenandoahBarrierStubC2::keepalive(MacroAssembler& masm, Label* L_done) {
- Address gc_state_fast(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::MARKING)));
Address index(r15_thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_index_offset()));
Address buffer(r15_thread, in_bytes(ShenandoahThreadLocalData::satb_mark_queue_buffer_offset()));
Label L_through, L_pop_and_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_load_ref_barrier) {
- assert(L_done == nullptr, "L_done is always null when _needs_load_ref_barrier is true");
- __ cmpb(gc_state_fast, 0);
- __ jcc(Assembler::equal, L_through);
+ assert(L_done == nullptr, "Should be");
+ // Emit the unconditional branch in the first version of the method.
+ // Let the rest of runtime figure out how to manage it.
+ // TODO: We could have spared the over-jump if patching knew we need the inverse branch.
+ char state_to_check = ShenandoahHeap::MARKING;
+ Label L_over;
+ __ relocate(barrier_Relocation::spec(), ShenandoahNMethod::gc_state_to_reloc(state_to_check));
+ __ jmp(L_over, /* maybe_short = */ false);
+ __ jmp(L_through);
+ __ bind(L_over);
}
// Need temp to work, allocate one now.
bool tmp_live;
Register tmp = select_temp_register(tmp_live);
}
void ShenandoahBarrierStubC2::lrb(MacroAssembler& masm) {
Label L_pop_and_slow, L_slow;
- // If another barrier is enabled as well, do a runtime 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(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(state_to_check)));
- __ cmpb(gc_state_fast, 0);
- __ jcc(Assembler::equal, *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(r15_thread, in_bytes(ShenandoahThreadLocalData::gc_state_fast_array_offset(ShenandoahHeap::WEAK_ROOTS)));
- __ cmpb(gc_state_fast, 0);
- __ jccb(Assembler::notEqual, L_slow);
+ char state_to_check = ShenandoahHeap::WEAK_ROOTS;
+ __ relocate(barrier_Relocation::spec(), ShenandoahNMethod::gc_state_to_reloc(state_to_check));
+ __ jmp(L_slow, /* maybe_short = */ false);
+ }
+
+ if (_needs_keep_alive_barrier) {
+ // Emit the unconditional branch in the first version of the method.
+ // Let the rest of runtime figure out how to manage it.
+ // TODO: We could have spared the over-jump if patching knew we need the inverse branch.
+ char state_to_check = ShenandoahHeap::HAS_FORWARDED | (_needs_load_ref_weak_barrier ? ShenandoahHeap::WEAK_ROOTS : 0);
+ Label L_over;
+ __ relocate(barrier_Relocation::spec(), ShenandoahNMethod::gc_state_to_reloc(state_to_check));
+ __ jmp(L_over, /* maybe_short = */ false);
+ __ jmp(*continuation());
+ __ bind(L_over);
}
bool is_aot = AOTCodeCache::is_on_for_dump();
// Need temp to work, allocate one now.
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