On Wed, 27 May 2026 15:29:17 GMT, George Adams <[email protected]> wrote:
>> Building the JDK on macOS with the Xcode 26 linker (ld version 1267)
>> produces:
>>
>>
>> ld: warning: reducing alignment of section __DATA,__common from 0x8000 to
>> 0x4000 because it exceeds segment maximum alignment
>>
>>
>> This comes from libawt, specifically the tentative definitions of
>> `mul8table` and `div8table` in `AlphaMath.c`. These are 64KB uninitialized
>> global arrays that the compiler places in the __common section with 32KB
>> alignment. The Xcode 26 linker caps segment alignment at 16KB (the arm64
>> page size) and warns when clamping.
>>
>> The fix is to change the tentative definitions to explicit zero-initialized
>> definitions:
>>
>> Before:
>>
>> JNIEXPORT unsigned char mul8table[256][256];
>> JNIEXPORT unsigned char div8table[256][256];
>>
>>
>> After:
>>
>> JNIEXPORT unsigned char mul8table[256][256] = { { 0 } };
>> JNIEXPORT unsigned char div8table[256][256] = { { 0 } };
>>
>>
>> This moves the symbols from __common to __bss, avoiding the alignment
>> warning. Both sections are zero-filled at load time, and `initAlphaTables()`
>> populates the actual values at runtime, so the change is functionally
>> identical. No impact on other platforms.
>>
>> ---------
>> - [x] I confirm that I make this contribution in accordance with the
>> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai).
>
> George Adams has updated the pull request incrementally with one additional
> commit since the last revision:
>
> bump copyright year
Hah. I've been seeing that warning for months and I didn't realise it was
because of 2d code .. I assumed hotspot :-)
Never had time to look into it.
The change silences it .. let me just run our tests.
-------------
PR Comment: https://git.openjdk.org/jdk/pull/31294#issuecomment-4557110448
