This change modifies `Zcu.ErrorMsg` to store a `Zcu.LazySrcLoc` rather
than a `Zcu.SrcLoc`. Everything else is dominoes.
The reason for this change is incremental compilation. If a failed
`AnalUnit` is up-to-date on an update, we want to re-use the old error
messages. However, the file containing the error location may have been
modified, and `SrcLoc` cannot survive such a modification. `LazySrcLoc`
is designed to be correct across incremental updates. Therefore, we
defer source location resolution until `Compilation` gathers the compile
errors into the `ErrorBundle`.
This change seeks to more appropriately model the way semantic analysis
works by drawing a more clear line between errors emitted by analyzing a
`Decl` (in future a `Cau`) and errors emitted by analyzing a runtime
function.
This does change a few compile errors surrounding compile logs by adding
more "also here" notes. The new notes are more technically correct, but
perhaps not so helpful. They're not doing enough harm for me to put
extensive thought into this for now.
This commit reworks our representation of exported Decls and values in
Zcu to be memory-optimized and trivially serialized.
All exports are now stored in the `all_exports` array on `Zcu`. An
`AnalUnit` which performs an export (either through an `export`
annotation or by containing an analyzed `@export`) gains an entry into
`single_exports` if it performs only one export, or `multi_exports` if
it performs multiple.
We no longer store a persistent mapping from a `Decl`/value to all
exports of that entity; this state is not necessary for the majority of
the pipeline. Instead, we construct it in `Zcu.processExports`, just
before flush. This does not affect the algorithmic complexity of
`processExports`, since this function already iterates all exports in
the `Zcu`.
The elimination of `decl_exports` and `value_exports` led to a few
non-trivial backend changes. The LLVM backend has been wrangled into a
more reasonable state in general regarding exports and externs. The C
backend is currently disabled in this commit, because its support for
`export` was quite broken, and that was exposed by this work -- I'm
hoping @jacobly0 will be able to pick this up!
This patch is a pure rename plus only changing the file path in
`@import` sites, so it is expected to not create version control
conflicts, even when rebasing.
`LazySrcLoc` now stores a reference to the "base AST node" to which it
is relative. The previous tagged union is `LazySrcLoc.Offset`. To make
working with this structure convenient, `Sema.Block` contains a
convenience `src` method which takes an `Offset` and returns a
`LazySrcLoc`.
The "base node" of a source location is no longer given by a `Decl`, but
rather a `TrackedInst` representing either a `declaration`,
`struct_decl`, `union_decl`, `enum_decl`, or `opaque_decl`. This is a
more appropriate model, and removes an unnecessary responsibility from
`Decl` in preparation for the upcoming refactor which will split it into
`Nav` and `Cau`.
As a part of these `Decl` reworks, the `src_node` field is eliminated.
This change aids incremental compilation, and simplifies `Decl`. In some
cases -- particularly in backends -- the source location of a
declaration is desired. This was previously `Decl.srcLoc` and worked for
any `Decl`. Now, it is `Decl.navSrcLoc` in reference to the upcoming
refactor, since the set of `Decl`s this works for precisely corresponds
to what will in future become a `Nav` -- that is, source-level
declarations and generic function instantiations, but *not* type owner
Decls.
This commit introduces more tags to `LazySrcLoc.Offset` so as to
eliminate the concept of `error.NeededSourceLocation`. Now, `.unneeded`
should only be used to assert that an error path is unreachable. In the
future, uses of `.unneeded` can probably be replaced with `undefined`.
The `src_decl` field of `Sema.Block` no longer has a role in type
resolution. Its main remaining purpose is to handle namespacing of type
names. It will be eliminated entirely in a future commit to remove
another undue responsibility from `Decl`.
It is worth noting that in future, the `Zcu.SrcLoc` type should probably
be eliminated entirely in favour of storing `Zcu.LazySrcLoc` values.
This is because `Zcu.SrcLoc` is not valid across incremental updates,
and we want to be able to reuse error messages from previous updates
even if the source file in question changed. The error reporting logic
should instead simply resolve the location from the `LazySrcLoc` on the
fly.
This is in preparation for some upcoming changes to how we represent
source locations in the compiler. The bulk of the change here is dealing
with the removal of `src()` methods from `Zir` types.
Deprecated aliases that are now compile errors:
- `std.fs.MAX_PATH_BYTES` (renamed to `std.fs.max_path_bytes`)
- `std.mem.tokenize` (split into `tokenizeAny`, `tokenizeSequence`, `tokenizeScalar`)
- `std.mem.split` (split into `splitSequence`, `splitAny`, `splitScalar`)
- `std.mem.splitBackwards` (split into `splitBackwardsSequence`, `splitBackwardsAny`, `splitBackwardsScalar`)
- `std.unicode`
+ `utf16leToUtf8Alloc`, `utf16leToUtf8AllocZ`, `utf16leToUtf8`, `fmtUtf16le` (all renamed to have capitalized `Le`)
+ `utf8ToUtf16LeWithNull` (renamed to `utf8ToUtf16LeAllocZ`)
- `std.zig.CrossTarget` (moved to `std.Target.Query`)
Deprecated `lib/std/std.zig` decls were deleted instead of made a `@compileError` because the `refAllDecls` in the test block would trigger the `@compileError`. The deleted top-level `std` namespaces are:
- `std.rand` (renamed to `std.Random`)
- `std.TailQueue` (renamed to `std.DoublyLinkedList`)
- `std.ChildProcess` (renamed/moved to `std.process.Child`)
This is not exhaustive. Deprecated aliases that I didn't touch:
+ `std.io.*`
+ `std.Build.*`
+ `std.builtin.Mode`
+ `std.zig.c_translation.CIntLiteralRadix`
+ anything in `src/`
This reverts commit a7de02e052.
This did not implement the accepted proposal, and I did not sign off
on the changes. I would like a chance to review this, please.
Clang 17 passed struct{f128} parameters using rdi and rax, while Clang
18 matches GCC 13.2 behavior, passing them using xmm0.
This commit makes Zig's LLVM backend match Clang 18 and GCC 13.2. The
commit deletes a hack in x86_64/abi.zig which miscategorized f128 as
"memory" which obviously disagreed with the spec.
LLVM now refuses to lower arguments and return values on x86 targets
when the total vector bit size is >= 512.
This code detects such a situation and uses byref instead of byval.
* some manual fixes to generated CPU features code. In the future it
would be nice to make the script do those automatically.
* add to various target OS switches. Some of the values I was unsure of
and added TODO panics, for example in the case of spirv CPU arch.
This was a "fake" type used to handle C varargs parameters, much like
generic poison. In fact, it is treated identically to generic poison in
all cases other than one (the final coercion of a call argument), which
is trivially special-cased. Thus, it makes sense to remove this special
tag and instead use `generic_poison_type` in its place. This fixes
several bugs in Sema related to missing handling of this tag.
Resolves: #19781
We've got a big one here! This commit reworks how we represent pointers
in the InternPool, and rewrites the logic for loading and storing from
them at comptime.
Firstly, the pointer representation. Previously, pointers were
represented in a highly structured manner: pointers to fields, array
elements, etc, were explicitly represented. This works well for simple
cases, but is quite difficult to handle in the cases of unusual
reinterpretations, pointer casts, offsets, etc. Therefore, pointers are
now represented in a more "flat" manner. For types without well-defined
layouts -- such as comptime-only types, automatic-layout aggregates, and
so on -- we still use this "hierarchical" structure. However, for types
with well-defined layouts, we use a byte offset associated with the
pointer. This allows the comptime pointer access logic to deal with
reinterpreted pointers far more gracefully, because the "base address"
of a pointer -- for instance a `field` -- is a single value which
pointer accesses cannot exceed since the parent has undefined layout.
This strategy is also more useful to most backends -- see the updated
logic in `codegen.zig` and `codegen/llvm.zig`. For backends which do
prefer a chain of field and elements accesses for lowering pointer
values, such as SPIR-V, there is a helpful function in `Value` which
creates a strategy to derive a pointer value using ideally only field
and element accesses. This is actually more correct than the previous
logic, since it correctly handles pointer casts which, after the dust
has settled, end up referring exactly to an aggregate field or array
element.
In terms of the pointer access code, it has been rewritten from the
ground up. The old logic had become rather a mess of special cases being
added whenever bugs were hit, and was still riddled with bugs. The new
logic was written to handle the "difficult" cases correctly, the most
notable of which is restructuring of a comptime-only array (for
instance, converting a `[3][2]comptime_int` to a `[2][3]comptime_int`.
Currently, the logic for loading and storing work somewhat differently,
but a future change will likely improve the loading logic to bring it
more in line with the store strategy. As far as I can tell, the rewrite
has fixed all bugs exposed by #19414.
As a part of this, the comptime bitcast logic has also been rewritten.
Previously, bitcasts simply worked by serializing the entire value into
an in-memory buffer, then deserializing it. This strategy has two key
weaknesses: pointers, and undefined values. Representations of these
values at comptime cannot be easily serialized/deserialized whilst
preserving data, which means many bitcasts would become runtime-known if
pointers were involved, or would turn `undefined` values into `0xAA`.
The new logic works by "flattening" the datastructure to be cast into a
sequence of bit-packed atomic values, and then "unflattening" it; using
serialization when necessary, but with special handling for `undefined`
values and for pointers which align in virtual memory. The resulting
code is definitely slower -- more on this later -- but it is correct.
The pointer access and bitcast logic required some helper functions and
types which are not generally useful elsewhere, so I opted to split them
into separate files `Sema/comptime_ptr_access.zig` and
`Sema/bitcast.zig`, with simple re-exports in `Sema.zig` for their small
public APIs.
Whilst working on this branch, I caught various unrelated bugs with
transitive Sema errors, and with the handling of `undefined` values.
These bugs have been fixed, and corresponding behavior test added.
In terms of performance, I do anticipate that this commit will regress
performance somewhat, because the new pointer access and bitcast logic
is necessarily more complex. I have not yet taken performance
measurements, but will do shortly, and post the results in this PR. If
the performance regression is severe, I will do work to to optimize the
new logic before merge.
Resolves: #19452Resolves: #19460
Legacy anon decls now have three uses:
* Type owner decls
* Function owner decls
* `@export` and `@extern`
Therefore, there are no longer any cases where we wish to explicitly
omit legacy anon decls from the binary. This means we can remove the
concept of an "alive" vs "dead" `Decl`, which also allows us to remove
the separate `anon_work_queue` in `Compilation`.
Good riddance!
Most of these changes are trivial. There's a fix for a minor bug this
exposed in `Value.readFromPackedMemory`, but aside from that, it's all
just things like changing `intern` calls to `toIntern`.
`Decl` can no longer store un-interned values, so this field is now
unnecessary. The type can instead be fetched with the new `typeOf`
helper method, which just gets the type of the Decl's `Value`.
