On Thu, 9 Apr 2026 12:32:12 GMT, Paul Hübner <[email protected]> wrote:

>> Stefan Karlsson has updated the pull request incrementally with one 
>> additional commit since the last revision:
>> 
>>   Update markWord.hpp
>
> src/hotspot/share/oops/markWord.hpp line 142:
> 
>> 140:   static const int hash_shift                     = 
>> valhalla_reserved_shift + valhalla_reserved_bits;
>> 141: 
>> 142:   #define mask_in_place(bits, shift) (right_n_bits(bits) << (shift))
> 
> Nit: I skimmed the HotSpot style guide and couldn't find anything regarding 
> case, but I was under the impression we used all uppercase for runtime 
> macros. For example, `#define DISABLE_FLAG_AND_WARN_IF_NOT_DEFAULT(flag)`.

You are probably right, but I really dislike seeing screamy macros in my code. 
I would rather just get rid of these macros and checks just to not have to 
pollute this code with upper-case macros.

I had one version of this that used template functions, but I couldn't get it 
to work confined to the markWord class. One alternative would be to put those 
functions high up in the file, but I prefer to keep the markWord class the 
first entity in this file. Another alternative would be to put it in 
globalDefinitions.hpp, but `bit_in_place` is somewhat obscure because of the 
static assert.

Let me think a little bit about this.

> src/hotspot/share/oops/markWord.hpp line 156:
> 
>> 154:   static const uintptr_t null_free_array_bit_in_place = 
>> bit_in_place(null_free_array_bits,  null_free_array_shift);
>> 155:   static const uintptr_t flat_array_bit_in_place  = 
>> bit_in_place(flat_array_bits, flat_array_shift);
>> 156:   static const uintptr_t valhalla_reserved_bit_in_place = 
>> bit_in_place(valhalla_reserved_bits, valhalla_reserved_shift);
> 
> Nit: alignment.

Could you clarify what alignment you want me to fix? There's a pre-existing 
alignment issue because these names are so long. Fixing that would require 
re-aligning all constants in this file. I can do that, but I think it would be 
nice to do so as a follow-up. But maybe there was some other alignment issue 
you were thinking about. I saw a double space in the vicinity, so I removed 
that one.

-------------

PR Review Comment: 
https://git.openjdk.org/valhalla/pull/2310#discussion_r3057996989
PR Review Comment: 
https://git.openjdk.org/valhalla/pull/2310#discussion_r3058022612

Reply via email to