8255479: [aarch64] assert(src->section_index_of(target) == CodeBuffer::SECT_NONE) failed: sanity

Reviewed-by: aph, neliasso

Author: Patric Hedlin

src/hotspot/cpu/aarch64/gc/g1/g1BarrierSetAssembler_aarch64.cpp

@@ -220,7 +220,6 @@ void G1BarrierSetAssembler::g1_write_barrier_post(MacroAssembler* masm,
 
   // storing region crossing non-NULL, is card already dirty?
 
-  ExternalAddress cardtable((address) ct->byte_map_base());
   const Register card_addr = tmp;
 
   __ lsr(card_addr, store_addr, CardTable::card_shift);

src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp

@@ -4429,18 +4429,9 @@ void MacroAssembler::load_byte_map_base(Register reg) {
   CardTable::CardValue* byte_map_base =
     ((CardTableBarrierSet*)(BarrierSet::barrier_set()))->card_table()->byte_map_base();
 
-  if (is_valid_AArch64_address((address)byte_map_base)) {
-    // Strictly speaking the byte_map_base isn't an address at all,
-    // and it might even be negative.
-    uint64_t offset;
-    adrp(reg, ExternalAddress((address)byte_map_base), offset);
-    // We expect offset to be zero with most collectors.
-    if (offset != 0) {
-      add(reg, reg, offset);
-    }
-  } else {
-    mov(reg, (uint64_t)byte_map_base);
-  }
+  // Strictly speaking the byte_map_base isn't an address at all, and it might
+  // even be negative. It is thus materialised as a constant.
+  mov(reg, (uint64_t)byte_map_base);
 }
 
 void MacroAssembler::build_frame(int framesize) {

src/hotspot/share/code/relocInfo.cpp

@@ -732,16 +732,16 @@ bool static_stub_Relocation::clear_inline_cache() {
 
 
 void external_word_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {
-  address target = _target;
-  if (target == NULL) {
-    // An absolute embedded reference to an external location,
-    // which means there is nothing to fix here.
-    return;
-  }
-  // Probably this reference is absolute, not relative, so the
-  // following is probably a no-op.
-  assert(src->section_index_of(target) == CodeBuffer::SECT_NONE, "sanity");
-  set_value(target);
+  if (_target != NULL) {
+    // Probably this reference is absolute,  not relative, so the following is
+    // probably a no-op.
+    set_value(_target);
+  }
+  // If target is NULL, this is  an absolute embedded reference to an external
+  // location, which means  there is nothing to fix here.  In either case, the
+  // resulting target should be an "external" address.
+  postcond(src->section_index_of(target()) == CodeBuffer::SECT_NONE);
+  postcond(dest->section_index_of(target()) == CodeBuffer::SECT_NONE);
 }