src/hotspot/share/gc/z/zBarrierSet.cpp

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#include "gc/z/zBarrierSet.hpp"
#include "gc/z/zBarrierSetAssembler.hpp"
#include "gc/z/zBarrierSetNMethod.hpp"
#include "gc/z/zBarrierSetStackChunk.hpp"
#include "gc/z/zGeneration.inline.hpp"
#include "gc/z/zGlobals.hpp"
#include "gc/z/zHeap.inline.hpp"
#include "gc/z/zStackWatermark.hpp"
#include "gc/z/zThreadLocalData.hpp"
#include "runtime/deoptimization.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/registerMap.hpp"
#include "runtime/stackWatermarkSet.hpp"
#include "utilities/macros.hpp"
#ifdef COMPILER1
#include "gc/z/c1/zBarrierSetC1.hpp"
#endif
#ifdef COMPILER2
#include "gc/z/c2/zBarrierSetC2.hpp"
#endif

class ZBarrierSetC1;
class ZBarrierSetC2;

ZBarrierSet::ZBarrierSet()
  : BarrierSet(make_barrier_set_assembler<ZBarrierSetAssembler>(),
               make_barrier_set_c1<ZBarrierSetC1>(),
               make_barrier_set_c2<ZBarrierSetC2>(),
               new ZBarrierSetNMethod(),
               new ZBarrierSetStackChunk(),
               BarrierSet::FakeRtti(BarrierSet::ZBarrierSet)) {}

ZBarrierSetAssembler* ZBarrierSet::assembler() {
  BarrierSetAssembler* const bsa = BarrierSet::barrier_set()->barrier_set_assembler();
  return reinterpret_cast<ZBarrierSetAssembler*>(bsa);
}

bool ZBarrierSet::barrier_needed(DecoratorSet decorators, BasicType type) {
  assert((decorators & AS_RAW) == 0, "Unexpected decorator");
  //assert((decorators & ON_UNKNOWN_OOP_REF) == 0, "Unexpected decorator");

  if (is_reference_type(type)) {
    assert((decorators & (IN_HEAP | IN_NATIVE)) != 0, "Where is reference?");
    // Barrier needed even when IN_NATIVE, to allow concurrent scanning.
    return true;
  }

  // Barrier not needed
  return false;
}

void ZBarrierSet::on_thread_create(Thread* thread) {
  // Create thread local data
  ZThreadLocalData::create(thread);
}

void ZBarrierSet::on_thread_destroy(Thread* thread) {
  // Destroy thread local data
  ZThreadLocalData::destroy(thread);
}

void ZBarrierSet::on_thread_attach(Thread* thread) {
  // Set thread local masks
  ZThreadLocalData::set_load_bad_mask(thread, ZPointerLoadBadMask);
  ZThreadLocalData::set_load_good_mask(thread, ZPointerLoadGoodMask);
  ZThreadLocalData::set_mark_bad_mask(thread, ZPointerMarkBadMask);
  ZThreadLocalData::set_store_bad_mask(thread, ZPointerStoreBadMask);
  ZThreadLocalData::set_store_good_mask(thread, ZPointerStoreGoodMask);
  ZThreadLocalData::set_nmethod_disarmed(thread, ZPointerStoreGoodMask);
  if (thread->is_Java_thread()) {
    JavaThread* const jt = JavaThread::cast(thread);
    StackWatermark* const watermark = new ZStackWatermark(jt);
    StackWatermarkSet::add_watermark(jt, watermark);
    ZThreadLocalData::store_barrier_buffer(jt)->initialize();
  }
}

void ZBarrierSet::on_thread_detach(Thread* thread) {
  // Flush and free any remaining mark stacks
  ZHeap::heap()->mark_flush(thread);
}

static void deoptimize_allocation(JavaThread* thread) {
  RegisterMap reg_map(thread, RegisterMap::UpdateMap::skip,
                      RegisterMap::ProcessFrames::include,
                      RegisterMap::WalkContinuation::skip);
  const frame runtime_frame = thread->last_frame();
  assert(runtime_frame.is_runtime_frame(), "must be runtime frame");

  const frame caller_frame = runtime_frame.sender(&reg_map);
  assert(caller_frame.is_compiled_frame(), "must be compiled");

  const nmethod* const nm = caller_frame.cb()->as_nmethod();
  if ((nm->is_compiled_by_c2() || nm->is_compiled_by_jvmci()) && !caller_frame.is_deoptimized_frame()) {
    // The JIT might have elided barriers on this object so deoptimize the frame and let the
    // intepreter deal with it.
    Deoptimization::deoptimize_frame(thread, caller_frame.id());
  }
}

void ZBarrierSet::on_slowpath_allocation_exit(JavaThread* thread, oop new_obj) {
  const ZPage* const page = ZHeap::heap()->page(to_zaddress(new_obj));
  const ZPageAge age = page->age();
  if (age == ZPageAge::old) {
    // We promised C2 that its allocations would end up in young gen. This object
    // breaks that promise. Take a few steps in the interpreter instead, which has
    // no such assumptions about where an object resides.
    deoptimize_allocation(thread);
    return;
  }

  if (!ZGeneration::young()->is_phase_mark_complete()) {
    return;
  }

  if (!page->is_relocatable()) {
    return;
  }

  if (ZRelocate::compute_to_age(age) != ZPageAge::old) {
    return;
  }

  // If the object is young, we have to still be careful that it isn't racingly
  // about to get promoted to the old generation. That causes issues when null
  // pointers are supposed to be coloured, but the JIT is a bit sloppy and
  // reinitializes memory with raw nulls. We detect this situation and detune
  // rather than relying on the JIT to never be sloppy with redundant initialization.
  deoptimize_allocation(thread);
}

void ZBarrierSet::clone_obj_array(objArrayOop src_obj, objArrayOop dst_obj) {
  volatile zpointer* src = (volatile zpointer*)src_obj->base();
  volatile zpointer* dst = (volatile zpointer*)dst_obj->base();
  const int length = src_obj->length();

  for (const volatile zpointer* const end = src + length; src < end; src++, dst++) {
    zaddress elem = ZBarrier::load_barrier_on_oop_field(src);
    // We avoid healing here because the store below colors the pointer store good,
    // hence avoiding the cost of a CAS.
    ZBarrier::store_barrier_on_heap_oop_field(dst, false /* heal */);
    Atomic::store(dst, ZAddress::store_good(elem));
  }
}

void ZBarrierSet::print_on(outputStream* st) const {
  st->print_cr("ZBarrierSet");
}