Date: Thu, 31 Mar 2016 17:35:11 -0700 From: Dan Gohman <sunfish@...illa.com> To: musl@...ts.openwall.com Subject: Re: size_t and int64_t on a new platform On Thu, Mar 31, 2016 at 12:25 PM, Rich Felker <dalias@...c.org> wrote: > On Thu, Mar 31, 2016 at 11:20:22AM -0700, Dan Gohman wrote: > > I'm working on a new architecture (WebAssembly, aka wasm) and am hoping > to > > have a compatible ABI at the level of a "freestanding implementation" > > between all libc ports. > > > > The current design would translate into the following in a musl port (in > > ..../bits/alltypes.h.in): > > > > #define _Addr long > > #define _Int64 long long > > > > Both the ILP32 and LP64 platform variants would use the same definitions. > > This helps minimize differences between the two variants, which aligns > with > > an overall goal of the platform. > > > > However, this differs from musl's convention of using "int" for _Addr on > > ILP32 systems and using "long" for _Int64 on LP64 systems. But, as far > as I > > can tell, no musl code actually depends on this convention. Almost all > code > > in musl is either fully portable and can't, or is architecture-specific > and > > can just do the right thing for its own architecture. > > > > Legacy code may have assumptions, though I'm aware of the issues and > don't > > believe it's a significant practical problem for WebAssembly. > > > > If we decide to contribute wasm support upstream to the musl project in > the > > future, would the musl maintainers expect to be ok with the above > > definitions? > > At some point we'll probably have to make this relaxation anyway. I've > heard there's at least one arch we're planning to add (maybe > powerpc64? I forget) that's using long instead of int for _Addr types. > What would be most helpful to us (to keep things simple) is just > ensuring that all the relevant types (size_t, ssize_t, ptrdiff_t, > [u]intptr_t, etc.) are defined consistently as int or as long; > otherwise we have to pop a hole in the abstraction they're modeled > with now. That wouldn't be a huge problem either but it just adds more > redundancy to arch/*/bits/alltypes.h.in files. > Sounds good. And I agree; size_t, ssize_t, ptrdiff_t, [u]intptr_t, etc. would all remain consistent with each other. And to answer the concerns about compilers, I'm also a developer on the first C/C++ compiler being ported to this platform, so I'll make sure that the compiler's types agree with those defined in the library headers. Thanks, Dan Content of type "text/html" skipped
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