This change adds support for locating the Zig executable and the library
and global cache directories, based on looking in the fixed "/zig" and
"/cache" directories.
Since our argv[0] on WASI is just the basename (any absolute/relative
path information is deleted by the runtime), there's very limited
introspection we can do on WASI, so we rely on these fixed directories.
These can be provided on the command-line using `--mapdir`, as follows:
```
wasmtime --mapdir=/cwd::. --mapdir=/cache::"$HOME/.cache/zig" --mapdir=/zig::./zig-out/ ./zig-out/bin/zig.wasm
```
Two major changes here:
1. We store the CWD as a simple `[]const u8` and lookup Preopens for
every absolute or CWD-referenced file operation, based on the
Preopen with the longest match (i.e. most specific path)
2. Preorders are normalized to POSIX absolute paths at init time.
Behavior depends on the "cwd_root" parameter of `initPreopensWasi`:
`cwd_root` is used for any Preopens that start with "."
For example:
"./foo/bar" - inits to -> "{cwd_root}/foo/bar"
"foo/bar" - inits to -> "/foo/bar"
"/foo/bar" - inits to -> "/foo/bar"
`cwd_root` must be an absolute path.
Using "/" as `cwd_root` gives behavior similar to wasi-libc.
According to Apple docs, the long double type is a double precision
IEEE754 binary floating-point type, which makes it identical to the
double type. This behavior contrasts to the standard specification,
in which a long double is a quad-precision, IEEE754 binary,
floating-point type.
Thus, we need to take this into account when using the compiler
intrinsics so that we select the correct function version for
FloatMulAdd.
The call to `makeDir` for the top-level component of `sub_path`
can return `error.FileNotFound` if the directory represented by
`self` has been deleted.
Fixes#11397
Some SPARC CPUs (particularly old and/or embedded ones) only has atomic
TAS instruction available (`ldstub`). This adds support for emitting
that instruction in the spinlock.
Previously, the data segments were being aligned twice.
This caused us to overalign the segment and therefore allocate a much larger
size for each segment than was required. This fix ensures we align and set the size
just once, ensuring semantically correct binaries as well as smaller binaries.
When linking with an object file, verify if a relocation is a table index relocation.
If that's the case, add the relocation target to the function table.
This fixes a memory leak when an object file contains one or more element sections which
then contains one or more function indexes. This commit ensures the slice of index functions
for each element section will be freed upon resource deallocation also.
