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.
Instead of explicitly creating a `Module.Decl` object for each anonymous
declaration, each `InternPool.Index` value is implicitly understood to
be an anonymous declaration when encountered by backend codegen.
The memory management strategy for these anonymous decls then becomes to
garbage collect them along with standard InternPool garbage.
In the interest of a smooth transition, this commit only implements this
new scheme for string literals and leaves all the previous mechanisms in
place.
* add nested packed struct/union behavior tests
* use ptr_info.packed_offset rather than trying to duplicate the logic from Sema.structFieldPtrByIndex()
* use the container_ptr_info.packed_offset to account for non-aligned nested structs.
* dedup type.packedStructFieldBitOffset() and module.structPackedFieldBitOffset()
zig fetch [options] <url>
zig fetch [options] <path>
Fetches a package which is found at <url> or <path> into the global
cache directory, printing the package hash to stdout.
Closes#16972
Related to #14280
Additionally, this commit:
* Adds uncompressed .tar support to package fetching
* Introduces symlink support to package fetching
- 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
My previous change for reading / writing to unions at comptime did not handle
union field read/writes correctly in all cases. Previously, if a field was
written to a union, it would overwrite the entire value. This is problematic
when a field of a larger size is subsequently read, because the value would not
be long enough, causing a panic.
Additionally, the writing behaviour itself was incorrect. Writing to a field of
a packed or extern union should only overwrite the bits corresponding to that
field, allowing for memory reintepretation via field writes / reads.
I addressed these problems as follows:
Add the concept of a "backing type" for extern / packed unions
(`Type.unionBackingType`). For extern unions, this is a `u8` array, for packed
unions it's an integer matching the `bitSize` of the union. Whenever union
memory is read at comptime, it's read as this type.
When union memory is written at comptime, the tag may still be known. If so, the
memory is written using the tagged type. If the tag is unknown (because this
union had previously been read from memory), it's simply written back out as the
backing type.
I added `write_packed` to the `reinterpret` field of
`ComptimePtrMutationKit`. This causes writes of the operand to be packed - which
is necessary when writing to a field of a packed union. Without this, writing a
value to a `u1` field would overwrite the entire byte it occupied.
The final case to address was reading a different (potentially larger) field
from a union when it was written with a known tag. To handle this, a new kind of
bitcast was introduced (`bitCastUnionFieldVal`) which supports reading a larger
field by using a backing buffer that has the unwritten bits set to
undefined. The reason to support this (vs always just writing the union as it's
backing type), is that no reads to larger fields ever occur at comptime, it
would be strictly worse to have spent time writing the full backing type.
