Use reloc info to find guard location

Author: tkrodriguez

src/hotspot/cpu/aarch64/gc/shared/barrierSetNMethod_aarch64.cpp

@@ -62,8 +62,13 @@ class NativeNMethodBarrier {
     address barrier_address;
 #if INCLUDE_JVMCI
     if (nm->is_compiled_by_jvmci()) {
-      _instruction_address = nm->code_begin() + nm->frame_complete_offset();
-      _guard_addr = reinterpret_cast<int*>(nm->consts_begin() + nm->jvmci_nmethod_data()->nmethod_entry_patch_offset());
+      address pc = nm->code_begin() + nm->jvmci_nmethod_data()->nmethod_entry_patch_offset();
+      RelocIterator iter(nm, pc, pc + 4);
+      guarantee(iter.next(), "missing relocs");
+      guarantee(iter.type() == relocInfo::section_word_type, "unexpected reloc");
+
+      _guard_addr = (int*) iter.section_word_reloc()->target();
+      _instruction_address = pc;
     } else
 #endif
       {

src/hotspot/cpu/aarch64/jvmciCodeInstaller_aarch64.cpp

@@ -90,10 +90,6 @@ void CodeInstaller::pd_patch_DataSectionReference(int pc_offset, int data_offset
   if (inst->is_adr_aligned() || inst->is_ldr_literal()
       || (NativeInstruction::maybe_cpool_ref(pc))) {
     address dest = _constants->start() + data_offset;
-    if (_nmethod_entry_patch_offset == pc_offset) {
-      // Remember the offset into constants
-      _nmethod_entry_patch_offset = data_offset;
-    }
     _instructions->relocate(pc, section_word_Relocation::spec((address) dest, CodeBuffer::SECT_CONSTS));
     JVMCI_event_3("relocating at " PTR_FORMAT " (+%d) with destination at %d", p2i(pc), pc_offset, data_offset);
   } else {