src/hotspot/cpu/riscv/c1_MacroAssembler_riscv.cpp

@@ -179,10 +179,14 @@
      sd(klass, Address(obj, oopDesc::klass_offset_in_bytes()));
    }
  
    if (len->is_valid()) {
      sw(len, Address(obj, arrayOopDesc::length_offset_in_bytes()));
+     if (!is_aligned(arrayOopDesc::header_size_in_bytes(), BytesPerWord)) {
+       assert(is_aligned(arrayOopDesc::header_size_in_bytes(), BytesPerInt), "must be 4-byte aligned");
+       sw(zr, Address(obj, arrayOopDesc::header_size_in_bytes()));
+     }
    } else if (UseCompressedClassPointers) {
      store_klass_gap(obj, zr);
    }
  }
  

@@ -278,11 +282,11 @@
    }
  
    verify_oop(obj);
  }
  
- void C1_MacroAssembler::allocate_array(Register obj, Register len, Register tmp1, Register tmp2, int header_size, int f, Register klass, Label& slow_case) {
+ void C1_MacroAssembler::allocate_array(Register obj, Register len, Register tmp1, Register tmp2, int base_offset_in_bytes, int f, Register klass, Label& slow_case) {
    assert_different_registers(obj, len, tmp1, tmp2, klass);
  
    // determine alignment mask
    assert(!(BytesPerWord & 1), "must be multiple of 2 for masking code to work");
  

@@ -290,21 +294,24 @@
    mv(t0, (int32_t)max_array_allocation_length);
    bgeu(len, t0, slow_case, /* is_far */ true);
  
    const Register arr_size = tmp2; // okay to be the same
    // align object end
-   mv(arr_size, (int32_t)header_size * BytesPerWord + MinObjAlignmentInBytesMask);
+   mv(arr_size, (int32_t)base_offset_in_bytes + MinObjAlignmentInBytesMask);
    shadd(arr_size, len, arr_size, t0, f);
    andi(arr_size, arr_size, ~(uint)MinObjAlignmentInBytesMask);
  
    try_allocate(obj, arr_size, 0, tmp1, tmp2, slow_case);
  
    initialize_header(obj, klass, len, tmp1, tmp2);
  
    // clear rest of allocated space
    const Register len_zero = len;
-   initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero);
+   // We align-up the header size to word-size, because we clear the
+   // possible alignment gap in initialize_header().
+   int hdr_size = align_up(base_offset_in_bytes, BytesPerWord);
+   initialize_body(obj, arr_size, hdr_size, len_zero);
  
    membar(MacroAssembler::StoreStore);
  
    if (CURRENT_ENV->dtrace_alloc_probes()) {
      assert(obj == x10, "must be");