When the last instruction is a debug instruction, the type of it is void.
Similarly for 'noreturn' emit an 'unreachable' instruction to tell the wasm-validator
the path cannot be reached.
Also respect the '--strip' flag in the self-hosted wasm linker and not emit a 'name' section
when the flag is set to `true`.
There were a few minor bugs in the rounding behavior and Inf/NaN
handling for the f80 __addxf3 and __subtf3 functions.
This change updates the original generic implementation to correctly
handle f80 floats, including the explicit integer bit.
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.
