Bug#1032317: libc++-15-dev: after installing libc++-15-dev, wasi-wasm32 stddef.h stops declaring size_t

[Sylvestre Ledru]

Le 08/03/2023 à 02:30, Faidon Liambotis a écrit :
> On Fri, Mar 03, 2023 at 05:31:41PM +0000, Simon McVittie wrote:
>> # clang++-15 -c --target=wasi-wasm32 -ostddef-cpp.o stddef.cpp
>> # apt-get install --no-install-recommends libc++-15-dev
>> # clang++-15 -c --target=wasi-wasm32 -ostddef-cpp.o stddef.cpp
>>
>> Expected result: both clang++-15 calls succeed (stddef.h declares size_t)
>>
>> Actual result: the second clang++-15 call fails:
> (Super helpful bug report, thanks!)
>
> As I mentioned in #1029010 just now, this is a regression from 14->15.
> Retracing the same steps with clang-14 & libc++-14-dev-wasm32, there are
> no errors and everything works as intended.
>
> Looking at the differences of the include paths between the two by
> passing -v to clang, one can see:
>    /usr/include/wasm32-wasi/c++/v1
> - /usr/lib/llvm-14/lib/clang/14.0.6/include
> + /usr/include/c++/v1
> + /usr/lib/llvm-15/lib/clang/15.0.7/include
>    /usr/local/include
>    /usr/include/wasm32-wasi
>    /usr/include
> i.e. /usr/include/c++/v1 (i.e. libc++-15-dev) is included in the include
> path only with clang-15. It shouldn't be.
>
> Looking at the interdiff of d/patches/wasm/wasm-sysroot-usr.diff[1]
> patch between llvm-toolchain 1:14.0.6-12 and 1:15.0.7-1, it looks line
> there are a few hunks that are missing.
>
> Specifically, it looks like the entire patching of the method
> WebAssembly::AddClangCXXStdlibIncludeArgs isn't happening anymore. One
> of these differences was exactly about this -- the comment says:
>    // don't include the host architecture's headers in the search path
>
> Sylvestre, I think you did the 14->15 porting, right? Do you
> know/remember what happened there?

Maybe i did a mistake in the merge?!
Sorry if I did
S