Because `std.Io` forces analysis of unused functions in the vtable,
there are now references to 4 more WASI functions, even though the
compiler does not actually call them at runtime.
Therefore, these new stubs fix the bootstrap process after a zig1.wasm
update (though this branch does *not* update zig1.wasm).
It turns out we did use these in the C backend. However, it's really
just as easy, if not easier, to replicate the logic directly in C.
Synchronizes stage1/zig.h to make sure the bootstrap doesn't depend on
these functions either. The actual zig1 tarball is unmodified because
regenerating it is unnecessary in this instance.
This was causing a zig2 miscomp, which emitted slightly broken debug
information, which caused extremely slow stack unwinding. We're working
on fixing or reporting this upstream, but we can use this workaround for
now, because GCC guarantees arithmetic signed shift.
necessary because to pass `zig fmt --check` we need to use the canonical
identifier syntax, which means changing `.@"async"` to `.async` which
previous zig1 is unable to parse.
* Fix warning WasmMut_toC not all control paths return a value
This is a follow up to https://github.com/ziglang/zig/pull/24206 where
I had previously submitted different mechanisms to fix this warning.
This PR is a suggestion by Alex to return NULL instead and Andrew
confirmed this is his preference.
`wasm2c` uses an interesting mechanism to "fake" the existence of cache
directories. However, `wasi_snapshot_preview1_fd_seek` was not correctly
integrated with this system, so previously crashed when run on a file in
a cache directory due to trying to call `fseek` on a `FILE *` which was
`NULL`.
Implementing the changes from the prior commit, to prepare for the
following commit.
This also means that zig1 now uses the new value interpret mode, so
that adding and removing fields from `std.builtin` types is easier.
Signed-off-by: mlugg <mlugg@mlugg.co.uk>
* Make it work for thumb and aarch64.
* Clean up std.os.windows.teb() a bit.
I also updated stage1/zig.h since the changes are backwards-compatible and are
necessary due to the std.os.windows changes that call the newly-added functions.
I took a slightly unconventional approach to detecting endianness here. We have
no compiler/platform-specific preprocessor checks in the stage1 C code today,
and I think that's a property worth maintaining.
As well as being necessary for the `CallingConvention` changes, this
update includes the following notable changes:
* Fix unlabeled `break` targeting the wrong scope in the presence of
labeled continue, unblocking #21422
* Implement `@FieldType`
* Implement `@splat` on arrays
Signed-off-by: mlugg <mlugg@mlugg.co.uk>
This was causing zig2.exe to crash during bootstrap, because there was an atomic
load of read-only memory, and the attempt to write to it as part of the (idempotent)
atomic exchange was invalid.
Aligned reads (of u32 / u64) are atomic on x86 / x64, so this is replaced with an
optimization-proof load (`__iso_volatile_load8*`) and a reordering barrier.
Using zig cc to compile and run wasm2c on zig.wasm on Windows triggers
what appears to be a sanitizer crash. The FuncGen reuse array pointer is
initialized to null and at some point it's resized to a length of zero,
which triggers this code to execute:
memcpy(&self->reuse[self->reuse_i], &self->reuse[reuse_top], sizeof(uint32_t) * reuse_n);
Given the current values, this equates to:
memcpy(&(NULL)[0], &(NULL)[0], 0);
Taking the address of the first element of a null pointer doesn't trigger
any actual runtime problem, since the pointer won't be dereferenced because
were passing 0 as the length to memcpy, however, it seems that the C spec
considers indexing a null pointer to be undefined behavior even if you
don't use the resulting value (or are just taking the address of an
indexed pointer).
Alex Rønne Petersen