wasi-libc's copy of libpreopen has evolved so many local changes that
it's no longer worth keeping the upstream code structure and marking
changes with __wasilibc_unmodified_upstream.
This PR merges the source files into a single file, removes all
__wasilibc_unmodified_upstream code, eliminates the ability to
allocate multiple preopen lists, eliminates the need for
__wasilibc_init_preopen, eliminates the non-standard eaccess, and
makes several other cleanups. It also enables NDEBUG so that internal
assertions are disabled in release builds.
utime.h, sysmacros.h, and libintl.h are all currently unsupported.
Removing them helps programs that autodetect features based on the
existence of headers.
POSIX requires `environ` to be a pointer to a NULL-terminated array of
pointers, so it itself can't be NULL.
This fixes a regression in src/functional/env.c in wasi-libc-test.
* Link `populate_args` only if we actually need command-line arguments.
This avoids linking in the argv/argc initialization code,
and the __wasi_args_sizes_get and __wasi_args_get imports, in
programs that don't use command-line arguments. The way this works is,
if the user writes `int main(int argc, char *argv[])`, the argument
initialization code is loaded, and if they write `int main(void)`,
it's not loaded.
This promotes the `__original_main` mechanism into an effective contract
between the compiler and libc, which wasn't its original purpose,
however it seems to fit this purpose quite well.
* Document that `__original_main` may be the user's zero-arg `main`.
* Link `populate_environ` only if we actually need environment variables.
This avoids linking in the environment variable initialization code,
and the __wasi_environ_sizes_get and __wasi_environ_get imports, in
programs that don't use environment variables.
This also removes the "___environ" (three underscores) alias symbol,
which is only in musl for backwards compatibility.
* Switch to //-style comments.
* If malloc fails, don't leave `__environ` pointing to an uninitialized buffer.
* Fix a memory leak if one malloc succeeds and the other fails.
* Use calloc to handle multiplication overflow.
This also handles the NULL terminator.
* Don't initialize __environ until everything has succeeded.
* Avoid leaking in case __wasi_environ_get fails.
* Handle overflow in the add too.
* Add #include <stdlib.h> for malloc etc.
* If the environment is empty, don't allocate any memory.
* Remove -fno-builtin.
-fno-builtin suppresses optimizations such as turning calls to `sqrt`
or `fabs` into `f64.sqrt` or `f64.abs` instructions inline. Libc code
itself benefits from these optimizations.
I originally added this flag because historically it was needed when
building libc to avoid the compiler pattern-matching the body of memcpy
into a memcpy call, however clang no longer requires this.
* Expand the comment about why we use USE_DL_PREFIX in dlmalloc.
We already use the compiler's versions of these; this just moves from
having libc #include_next them to having libc just omit them entirely,
which is simpler.
This removes the special code to define musl's include guard, however
I originally added that when I was still working out how WASI's stddef.h
would interact with other code. I believe it's no longer important.
This isn't strictly required, as wasm SIMD loads and stores work on
unaligned memory. However, it may provide better performance. That said,
this isn't currently studied by any benchmarking.
The lseek optimization turns lseek calls into __wasilibc_tell calls when
possible, using macros and __builtin_constant_p. However, this isn't
safe in C++ code in the presence of namespaces and `using` declarations,
to just disable it in C++ for now.
For functions like sqrt, fabs, and others, use the builtin functions,
which provide single-instruction implementations, rather than using
musl's portable implementations.
My understanding is that these dummy libs represent libraries who's
contents, under musl, live in libc itself rather than being split out
into separate libs.
libc++/libc++abi are not provided my musl so doesn't make sense to
pretend that we provide them.
This replaces our custom `unlink` wrapper with an upstream one. We still
end up replacing the entire body with local changes, but this makes it
easier to see what those changes are.
The other change here is a fix to ignore repeated '/'s in paths.
WASI's values for SEEK_CUR, SEEK_SET, and SEEK_END differ from musl's
values, so fix musl code that bakes in knowledge of these values.
This fixes src/functional/memstream.c.
POSIX requires fcntl.h to define the SEEK_* macros, so this satisfies
that requirement. Also, this allows <stdio.h> to avoid including as much
unnecessary content.
This fixes one issue with src/api/fcntl.c.
These functions aren't specific to the underlying system call interface,
so they don't need to be in the "bottom half".
This also fixes src/functional/inet_pton.c and
src/regression/inet_pton-empty-last-field.c in musl's libc-test.
This was commented out earlier when timezone handling was more in flux,
but it's ok to minimally support this now.
This fixes src/functional/strftime.c in libc-test.
