RFR: 8365579: ml64.exe is not the right assembler for Windows aarch64 [v3]

[Magnus Ihse Bursie]

On Mon, 18 Aug 2025 16:24:30 GMT, Saint Wesonga <duke at openjdk.org> wrote:

>> I wonder why we still have the assembler for 32 bit, as the JDK no longer supports 32 bit Windows ever since Magnus nuked it from the codebase
>
>> I wonder why we still have the assembler for 32 bit, as the JDK no longer supports 32 bit Windows ever since Magnus nuked it from the codebase
> 
> I have filed https://bugs.openjdk.org/browse/JDK-8365707 to address that issue

Is this really so? The [documentation](https://learn.microsoft.com/en-us/cpp/assembler/masm/ml-and-ml64-command-line-reference?view=msvc-170) states:


/Ta filename 	Assembles source file whose name doesn't end with the .asm extension.


We want the compiler to actually do what we tell it to do, even if the files are named .S. 

Maybe this behavior has been changed in later versions, but I am a bit wary about removing it unless we have some official confirmation that `/Ta` is a no-op, and/or information on which version this started to happen.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26791#discussion_r2288537315