src/hotspot/cpu/aarch64/c1_MacroAssembler_aarch64.cpp

@@ -161,25 +161,15 @@
    }
  }
  
  void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) {
    assert_different_registers(obj, klass, len);
-   // This assumes that all prototype bits fit in an int32_t
-   mov(t1, (int32_t)(intptr_t)markWord::prototype().value());
+   ldr(t1, Address(klass, Klass::prototype_header_offset()));
    str(t1, Address(obj, oopDesc::mark_offset_in_bytes()));
  
-   if (UseCompressedClassPointers) { // Take care not to kill klass
-     encode_klass_not_null(t1, klass);
-     strw(t1, Address(obj, oopDesc::klass_offset_in_bytes()));
-   } else {
-     str(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
-   }
- 
    if (len->is_valid()) {
      strw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
-   } else if (UseCompressedClassPointers) {
-     store_klass_gap(obj, zr);
    }
  }
  
  // preserves obj, destroys len_in_bytes
  //

@@ -193,10 +183,16 @@
  
    // len_in_bytes is positive and ptr sized
    subs(len_in_bytes, len_in_bytes, hdr_size_in_bytes);
    br(Assembler::EQ, done);
  
+   // Zero first 4 bytes, if start offset is not word aligned.
+   if (!is_aligned(hdr_size_in_bytes, BytesPerWord)) {
+     strw(zr, Address(obj, hdr_size_in_bytes));
+     hdr_size_in_bytes += BytesPerInt;
+   }
+ 
    // zero_words() takes ptr in r10 and count in words in r11
    mov(rscratch1, len_in_bytes);
    lea(t1, Address(obj, hdr_size_in_bytes));
    lsr(t2, rscratch1, LogBytesPerWord);
    zero_words(t1, t2);

@@ -242,11 +238,11 @@
      far_call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id)));
    }
  
    verify_oop(obj);
  }
- void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, int f, Register klass, Label& slow_case) {
+ void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int base_offset_in_bytes, int f, Register klass, Label& slow_case) {
    assert_different_registers(obj, len, t1, t2, klass);
  
    // determine alignment mask
    assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work");
  

@@ -255,20 +251,20 @@
    cmp(len, rscratch1);
    br(Assembler::HS, slow_case);
  
    const Register arr_size = t2; // okay to be the same
    // align object end
-   mov(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
+   mov(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
    add(arr_size, arr_size, len, ext::uxtw, f);
    andr(arr_size, arr_size, ~MinObjAlignmentInBytesMask);
  
    try_allocate(obj, arr_size, 0, t1, t2, slow_case);
  
    initialize_header(obj, klass, len, t1, t2);
  
    // clear rest of allocated space
-   initialize_body(obj, arr_size, header_size * BytesPerWord, t1, t2);
+   initialize_body(obj, arr_size, base_offset_in_bytes, t1, t2);
  
    membar(StoreStore);
  
    if (CURRENT_ENV->dtrace_alloc_probes()) {
      assert(obj == r0, "must be");

@@ -281,11 +277,11 @@
  
  void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) {
    verify_oop(receiver);
    // explicit NULL check not needed since load from [klass_offset] causes a trap
    // check against inline cache
-   assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check");
+   assert(!MacroAssembler::needs_explicit_null_check(oopDesc::mark_offset_in_bytes()), "must add explicit null check");
  
    cmp_klass(receiver, iCache, rscratch1);
  }