Ensure all previous test cases are still passing, as well as add some basic tests for now
for testing pointers to the stack.
This means we can start implementing wasm's C ABI found at: https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md
We also simplified the block logic by always using 'void' block types and instead writing the value to a local,
which can then be referenced by continues instructions, as done currently by AIR.
Besides this, we also no longer need to insert blocks at an offset, as we simply write the saved temporary
after we create the block.
- This ensures we honor the user's integer size when performing wrapping operations.
- Also, instead of using ensureCapacity, we now use ensureUnusedCapacity.
* implement enough of ret_err_value to pass wasm tests
* only do the proper `@panic` implementation for the backends which
support it, which is currently only the C backend. The other backends
will see `@breakpoint(); unreachable;` same as before.
- I plan to do AIR memory layout reworking as a prerequisite to
fixing other backends, because that will help me put all the
constants up front, which will allow the codegen to lower to memory
without jumps.
* `@panic` is implemented using anon decls for the message. Makes it
easier on the backends. Might want to look into re-using decls for
this in the future.
* implement DWARF .debug_info for pointer-like optionals.
Since v0.23 release of Wasmtime, if we want to iterate a directory
Y then directory Y needed to have been granted `fd_readdir` right.
However, it is now also required for directory X to carry `fd_readdir`
right, and so on, up-chain all the way until we reach the preopen
(which possesses all rights by default).
This caused problems for us since our libstd implementation is more
fine-grained and allowed for parent dirs not to carry the right while
allow for iterating on its children. My proposal here is to always
grant `fd_readdir` right as part of
`std.fs.Dir.OpenDirOptions.access_sub_paths`. This seems to be the
approach taken by Rust also, plus we should be justified to take this
approach since WASI is experimental and snapshot1 will be discontinued
eventually and replaced with a new approach to access management
that will require a complete rewrite of our libstd anyhow.
This allows us to differentiate between regular locals and variables that create multiple locals
on the stack such as optionals and structs.
Now `struct_a = struct_b;` works and only updates a reference, rather than update all local's values.
Also created more test cases to test against this.
- When returning within a block, we must use an explicit return opcode. For now always emit the opcode when calling return, rather than using implicit return statements.
- Also added a more comprehensive test case to test for enum values using conditions
