[llvm-dev] (Question regarding the) incomplete "builtins library" of "Compiler-RT"

[Friedman, Eli via llvm-dev]

On 11/30/2018 8:31 AM, Stefan Kanthak via llvm-dev wrote:
> Hi @ll,
>
> compiler-rt implements (for example) the MSVC (really Windows)
> specific routines compiler-rt/lib/builtins/i386/chkstk.S and
> compiler-rt/lib/builtins/x86_64/chkstk.S as __chkstk_ms()
> See <http://msdn.microsoft.com/en-us/library/ms648426.aspx>
>
> Is there any special reason why compiler-rt doesn't implement
> other MSVC specific functions (alias builtins or "compiler
> intrinsics") for which clang/LLVM but generates calls?

There are two "Windows" targets supported by LLVM: one using the MinGW 
runtime, and the other using the MSVC runtime.  If you're targeting the 
MSVC runtime, it provides _aulldiv and friends; if you're targeting 
MinGW, LLVM won't refer to those routines.  So I can't see a scenario 
where we would need those routines in compiler-rt.

-Eli

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