ZGC: Concurrent execution stack processing

Author: fisk

src/hotspot/cpu/aarch64/aarch64.ad

@@ -1958,9 +1958,10 @@ void MachEpilogNode::format(PhaseRegAlloc *ra_, outputStream *st) const {
   }
 
   if (do_polling() && C->is_method_compilation()) {
-    st->print("# touch polling page\n\t");
-    st->print("ldr rscratch1, [rthread],#polling_page_offset\n\t");
-    st->print("ldr zr, [rscratch1]");
+    st->print("# test polling word\n\t");
+    st->print("ldr  rscratch1, [rthread],#%d\n\t", in_bytes(JavaThread::polling_word_offset()));
+    st->print("cmp  sp, rscratch1\n\t");
+    st->print("bhi #slow_path");
   }
 }
 #endif
@@ -1977,7 +1978,13 @@ void MachEpilogNode::emit(CodeBuffer &cbuf, PhaseRegAlloc *ra_) const {
   }
 
   if (do_polling() && C->is_method_compilation()) {
-    __ fetch_and_read_polling_page(rscratch1, relocInfo::poll_return_type);
+    Label dummy_label;
+    Label* code_stub = &dummy_label;
+    if (!C->output()->in_scratch_emit_size()) {
+      code_stub = &C->output()->safepoint_poll_table()->add_safepoint(_masm);
+    }
+    __ relocate(relocInfo::poll_return_type);
+    __ safepoint_poll(*code_stub, true /* at_return */, false /* acquire */, true /* in_nmethod */);
   }
 }
 

src/hotspot/cpu/aarch64/c1_CodeStubs_aarch64.cpp

@@ -38,6 +38,19 @@
 
 #define __ ce->masm()->
 
+void C1SafepointPollStub::emit_code(LIR_Assembler* ce) {
+  __ bind(_entry);
+  InternalAddress safepoint_pc(ce->masm()->pc() - ce->masm()->offset() + safepoint_offset());
+  __ lea(rscratch1, safepoint_pc);
+  __ str(rscratch1, Address(rthread, JavaThread::saved_exception_pc_offset()));
+
+  assert(SharedRuntime::polling_page_return_handler_blob() != NULL,
+         "polling page return stub not created yet");
+  address stub = SharedRuntime::polling_page_return_handler_blob()->entry_point();
+
+  __ far_jump(RuntimeAddress(stub));
+}
+
 void CounterOverflowStub::emit_code(LIR_Assembler* ce) {
   __ bind(_entry);
   Metadata *m = _method->as_constant_ptr()->as_metadata();