8146886: aarch64: fails to build following 8136525 and 8139864

Fix several build errors and warnings

Reviewed-by: aph
diff --git a/hotspot/src/cpu/aarch64/vm/macroAssembler_aarch64.cpp b/hotspot/src/cpu/aarch64/vm/macroAssembler_aarch64.cpp
index c64f127..f114981 100644
--- a/hotspot/src/cpu/aarch64/vm/macroAssembler_aarch64.cpp
+++ b/hotspot/src/cpu/aarch64/vm/macroAssembler_aarch64.cpp
@@ -3938,7 +3938,7 @@
   // was post-decremented.)  Skip this address by starting at i=1, and
   // touch a few more pages below.  N.B.  It is important to touch all
   // the way down to and including i=StackShadowPages.
-  for (int i = 0; i < (JavaThread::stack_shadow_zone_size() / os::vm_page_size()) - 1; i++) {
+  for (int i = 0; i < (int)(JavaThread::stack_shadow_zone_size() / os::vm_page_size()) - 1; i++) {
     // this could be any sized move but this is can be a debugging crumb
     // so the bigger the better.
     lea(tmp, Address(tmp, -os::vm_page_size()));
diff --git a/hotspot/src/cpu/aarch64/vm/templateInterpreterGenerator_aarch64.cpp b/hotspot/src/cpu/aarch64/vm/templateInterpreterGenerator_aarch64.cpp
index 37176c7..c363bca 100644
--- a/hotspot/src/cpu/aarch64/vm/templateInterpreterGenerator_aarch64.cpp
+++ b/hotspot/src/cpu/aarch64/vm/templateInterpreterGenerator_aarch64.cpp
@@ -716,7 +716,7 @@
 
   // If G1 is not enabled then attempt to go through the accessor entry point
   // Reference.get is an accessor
-  return generate_accessor_entry();
+  return NULL;
 }
 
 /**
@@ -842,7 +842,7 @@
   // an interpreter frame with greater than a page of locals, so each page
   // needs to be checked.  Only true for non-native.
   if (UseStackBanging) {
-    const int size_t n_shadow_pages = JavaThread::stack_shadow_zone_size() / os::vm_page_size();
+    const int n_shadow_pages = JavaThread::stack_shadow_zone_size() / os::vm_page_size();
     const int start_page = native_call ? n_shadow_pages : 1;
     const int page_size = os::vm_page_size();
     for (int pages = start_page; pages <= n_shadow_pages ; pages++) {
@@ -1184,8 +1184,8 @@
   {
     Label no_reguard;
     __ lea(rscratch1, Address(rthread, in_bytes(JavaThread::stack_guard_state_offset())));
-    __ ldrb(rscratch1, Address(rscratch1));
-    __ cmp(rscratch1, JavaThread::stack_guard_yellow_disabled);
+    __ ldrw(rscratch1, Address(rscratch1));
+    __ cmp(rscratch1, JavaThread::stack_guard_yellow_reserved_disabled);
     __ br(Assembler::NE, no_reguard);
 
     __ pusha(); // XXX only save smashed registers