Beyond adding default zero-initialization, this commit changes undefined
initialization to zero, as some cases reserved the padding and on other
cases, I've found some systems act strange when giving uninit instead of
zero even when it shouldn't be an issue, one example being
FileProtocol.Open's attributes, which *should* be ignored when not
creating a file, but ended up giving an unrelated error.
There is a mechanism to avoid redundant `as` ZIR instructions which is
to pass `ResultLoc.coerced_ty` instead of `ResultLoc.ty` when it is
known by AstGen that Sema will do the coercion.
This commit downgrades `coerced_ty` to `ty` when a result location
passes through an expression that branches, such as `if`, `switch`,
`while`, and `for`, causing the `as` ZIR instruction to be emitted.
This ensures that the type of a result location will be applied to, e.g.
a `comptime_int` on either side of a branch on a runtime condition.
I've seen having this be wrong break some cross-compilers, and it's
also how it is in other files so it's best to be consistent.
It's also just the actual casing of the file.
It is the job of codegen backends to mark Decls that are referenced as
alive so that the frontend does not sweep them with the garbage. This
commit unifies the code between the backends with an added method on
Decl.
The implementation is more complete than before, switching on the Decl
val tag and recursing into sub-values.
As a result, two more array tests are passing.
also use the common naming convention for glibc versions ("2.33" rather
than "2-33").
I also verified that these files are exactly identical to the previous
files from before zig updated to glibc 2.34.
__libc_start_main() from glibc.2.33.so or older needs to have a __libc_csu_init function callback parameter.
glibc-2.34 on the other hand has a different __libc_start_main() that does not use it,
and the start.S file from glibc-2.34 no longer construct the init function and pass null when calling __libc_start_main.
So, When targetting an older glibc, use the start.s files as they were in glibc-2.33 and construct the __libc_csu_init function.
fixes#10386#10512
Introduce `validate_array_init_comptime`, similar to
`validate_struct_init_comptime` introduced in
713d2a9b3883942491b40738245232680877cc66.
`zirValidateArrayInit` is improved to detect comptime array literals and
emit AIR accordingly. This code is very similar to the changes
introduced in that same commit for `zirValidateStructInit`.
The C backend needed some improvements to continue passing the same set
of tests:
* `resolveInst` for arrays now will add a local `static const` with the
array value and so then `elem_val` instructions reference that local.
It memoizes accesses using `value_map`, which is changed to use
`Air.Inst.Ref` as the key rather than `Air.Inst.Index`.
* This required a mechanism for writing to a "header" which is lines
that appear at the beginning of a function body, before everything
else.
* dbg_stmt output comments rather than `#line` directives.
TODO comment reproduced here:
We need to re-evaluate whether to emit these or not. If we naively emit
these directives, the output file will report bogus line numbers because
every newline after the #line directive adds one to the line.
We also don't print the filename yet, so the output is strictly unhelpful.
If we wanted to go this route, we would need to go all the way and not output
newlines until the next dbg_stmt occurs.
Perhaps an additional compilation option is in order?
`Value.elemValue` is improved to support `elem_ptr` values.
Handle `__DATA,.rustc` section containing `rustc` metadata - this
is required to get crates like `serde_derive` link properly.
Note to self: this special section has to be copied __verbatim__
from the relocatable object file - this includes preserving its size
even though unpadded according the section's required alignment.
