Implement the stub for Elf.
I believe that separating the concerns, namely, having an interface
function that is responsible for signalling the linker to lower
the anon decl only, and a separate function to obtain the decl's
vaddr is preferable since it allows us to handle codegen errors
in a simpler way.
Introduce the new mechanism needed to render anonymous decls to C code
that the frontend is now using.
The current strategy is to collect the set of used anonymous decls into
one ArrayHashMap for the entire compilation, and then render them during
flush().
In the future this may need to be adjusted for incremental compilation
purposes, so that removing a Decl from decl_table means that newly
unused anonymous decls are no longer rendered. However, let's do one
thing at a time. The only goal of this branch is to stop using
Module.Decl objects for unnamed constants.
Start keeping track of dependencies on anon decls for dependency
ordering during flush()
Currently this causes use of undefined symbols because these
dependencies need to get rendered into the output.
- Adds `illumos` to the `Target.Os.Tag` enum. A new function,
`isSolarish` has been added that returns true if the tag is either
Solaris or Illumos. This matches the naming convention found in Rust's
`libc` crate[1].
- Add the tag wherever `.solaris` is being checked against.
- Check for the C pre-processor macro `__illumos__` in CMake to set the
proper target tuple. Illumos distros patch their compilers to have
this in the "built-in" set (verified with `echo | cc -dM -E -`).
Alternatively you could check the output of `uname -o`.
Right now, both Solaris and Illumos import from `c/solaris.zig`. In the
future it may be worth putting the shared ABI bits in a base file, and
mixing that in with specific `c/solaris.zig`/`c/illumos.zig` files.
[1]: 6e02a329a2/src/unix/solarish
When the compiler's state lives through multiple Compilation.update()
calls, the C backend stores the rendered C source code for each
decl code body and forward declarations.
With this commit, the state is still stored, but it is managed in one
big array list in link/C.zig rather than many array lists, one for each
decl. This means simpler serialization and deserialization.
