The compiler actually doesn't need any functional changes for this: Sema
does reification based on the tag indices of `std.builtin.Type` already!
So, no zig1.wasm update is necessary.
This change is necessary to disallow name clashes between fields and
decls on a type, which is a prerequisite of #9938.
Without this, incremental updates which would change inferred error sets
fail, since they assume the IES is resolved and equals the old set,
resulting in false positive compile errors when e.g. coercing to an IES.
The old logic here had bitrotted, largely because there were some
incorrect `else` cases. This is now implemented correctly for all
current ZIR instructions. This prevents instructions being lost in
incremental updates, which is important for updates to be minimal.
Another big commit, sorry! This commit makes all fixes necessary for
incremental updates of the compiler itself (specifically, adding a
breakpoint to `zirCompileLog`) to succeed, at least on the frontend.
The biggest change here is a reform to how types are handled. It works
like this:
* When a type is first created in `zirStructDecl` etc, its namespace is
scanned. If the type requires resolution, an `interned` dependency is
declared for the containing `AnalUnit`.
* `zirThis` also declared an `interned` dependency for its `AnalUnit` on
the namespace's owner type.
* If the type's namespace changes, the surrounding source declaration
changes hash, so `zirStructDecl` etc will be hit again. We check
whether the namespace has been scanned this generation, and re-scan it
if not.
* Namespace lookups also check whether the namespace in question
requires a re-scan based on the generation. This is because there's no
guarantee that the `zirStructDecl` is re-analyzed before the namespace
lookup is re-analyzed.
* If a type's structure (essentially its fields) change, then the type's
`Cau` is considered outdated. When the type is re-analyzed due to
being outdated, or the `zirStructDecl` is re-analyzed by being
transitively outdated, or a corresponding `zirThis` is re-analyzed by
being transitively outdated, the struct type is recreated at a new
`InternPool` index. The namespace's owner is updated (but not
re-scanned, since that is handled by the mechanisms above), and the
old type, while remaining a valid `Index`, is removed from the map
metadata so it will never be found by lookups. `zirStructDecl` and
`zirThis` store an `interned` dependency on the *new* type.
Two fixes here.
* Prevent a crash when sorting the list of analysis errors when some
errors refer to lost source locations. These errors can be sorted
anywhere in the list, because they are (in theory) guaranteed to never
be emitted by the `resolveReferences` logic. This case occurs, for
instance, when a declaration has compile errors in the initial update
and is deleted in the second update.
* Prevent a crash when resolving the source location for `entire_file`
errors for a non-existent file. This is the bug underlying #20954.
Resolves: #20954.
This commit updates `Zcu.resolveReferences` to traverse the graph of
`AnalUnit` references (starting from the 1-3 roots of analysis) in order
to determine which `AnalUnit`s are referenced in an update. Errors for
unreferenced entities are omitted from the error bundle. However, note
that unreferenced `Nav`s are not removed from the binary.
This commit makes more progress towards incremental compilation, fixing
some crashes in the frontend. Notably, it fixes the regressions introduced
by #20964. It also cleans up the "outdated file root" mechanism, by
virtue of deleting it: we now detect outdated file roots just after
updating ZIR refs, and re-scan their namespaces.
Some of this is arbitrary since spirv (as opposed to spirv32/spirv64) refers to
the version with logical memory layout, i.e. no 'real' pointers. This change at
least matches what clang does.
The type `Zcu.Decl` in the compiler is problematic: over time it has
gained many responsibilities. Every source declaration, container type,
generic instantiation, and `@extern` has a `Decl`. The functions of
these `Decl`s are in some cases entirely disjoint.
After careful analysis, I determined that the two main responsibilities
of `Decl` are as follows:
* A `Decl` acts as the "subject" of semantic analysis at comptime. A
single unit of analysis is either a runtime function body, or a
`Decl`. It registers incremental dependencies, tracks analysis errors,
etc.
* A `Decl` acts as a "global variable": a pointer to it is consistent,
and it may be lowered to a specific symbol by the codegen backend.
This commit eliminates `Decl` and introduces new types to model these
responsibilities: `Cau` (Comptime Analysis Unit) and `Nav` (Named
Addressable Value).
Every source declaration, and every container type requiring resolution
(so *not* including `opaque`), has a `Cau`. For a source declaration,
this `Cau` performs the resolution of its value. (When #131 is
implemented, it is unsolved whether type and value resolution will share
a `Cau` or have two distinct `Cau`s.) For a type, this `Cau` is the
context in which type resolution occurs.
Every non-`comptime` source declaration, every generic instantiation,
and every distinct `extern` has a `Nav`. These are sent to codegen/link:
the backends by definition do not care about `Cau`s.
This commit has some minor technically-breaking changes surrounding
`usingnamespace`. I don't think they'll impact anyone, since the changes
are fixes around semantics which were previously inconsistent (the
behavior changed depending on hashmap iteration order!).
Aside from that, this changeset has no significant user-facing changes.
Instead, it is an internal refactor which makes it easier to correctly
model the responsibilities of different objects, particularly regarding
incremental compilation. The performance impact should be negligible,
but I will take measurements before merging this work into `master`.
Co-authored-by: Jacob Young <jacobly0@users.noreply.github.com>
Co-authored-by: Jakub Konka <kubkon@jakubkonka.com>
What is `sparcel`, you might ask? Good question!
If you take a peek in the SPARC v8 manual, §2.2, it is quite explicit that SPARC
v8 is a big-endian architecture. No little-endian or mixed-endian support to be
found here.
On the other hand, the SPARC v9 manual, in §3.2.1.2, states that it has support
for mixed-endian operation, with big-endian mode being the default.
Ok, so `sparcel` must just be referring to SPARC v9 running in little-endian
mode, surely?
Nope:
* 40b4fd7a3e/llvm/lib/Target/Sparc/SparcTargetMachine.cpp (L226)
* 40b4fd7a3e/llvm/lib/Target/Sparc/SparcTargetMachine.cpp (L104)
So, `sparcel` in LLVM is referring to some sort of fantastical little-endian
SPARC v8 architecture. I've scoured the internet and I can find absolutely no
evidence that such a thing exists or has ever existed. In fact, I can find no
evidence that a little-endian implementation of SPARC v9 ever existed, either.
Or any SPARC version, actually!
The support was added here: https://reviews.llvm.org/D8741
Notably, there is no mention whatsoever of what CPU this might be referring to,
and no justification given for the "but some are little" comment added in the
patch.
My best guess is that this might have been some private exercise in creating a
little-endian version of SPARC that never saw the light of day. Given that SPARC
v8 explicitly doesn't support little-endian operation (let alone little-endian
instruction encoding!), and no CPU is known to be implemented as such, I think
it's very reasonable for us to just remove this support.
This is a misfeature that we inherited from LLVM:
* https://reviews.llvm.org/D61259
* https://reviews.llvm.org/D61939
(`aarch64_32` and `arm64_32` are equivalent.)
I truly have no idea why this triple passed review in LLVM. It is, to date, the
*only* tag in the architecture component that is not, in fact, an architecture.
In reality, it is just an ILP32 ABI for AArch64 (*not* AArch32).
The triples that use `aarch64_32` look like `aarch64_32-apple-watchos`. Yes,
that triple is exactly what you think; it has no ABI component. They really,
seriously did this.
Since only Apple could come up with silliness like this, it should come as no
surprise that no one else uses `aarch64_32`. Later on, a GNU ILP32 ABI for
AArch64 was developed, and support was added to LLVM:
* https://reviews.llvm.org/D94143
* https://reviews.llvm.org/D104931
Here, sanity seems to have prevailed, and a triple using this ABI looks like
`aarch64-linux-gnu_ilp32` as you would expect.
As can be seen from the diffs in this commit, there was plenty of confusion
throughout the Zig codebase about what exactly `aarch64_32` was. So let's just
remove it. In its place, we'll use `aarch64-watchos-ilp32`,
`aarch64-linux-gnuilp32`, and so on. We'll then translate these appropriately
when talking to LLVM. Hence, this commit adds the `ilp32` ABI tag (we already
have `gnuilp32`).
This was added as an architecture to LLVM's target triple parser and the Clang
driver in 2015. No backend ever materialized as far as I can see (same for GCC).
In 2016, other code referring to it started using "Myriad" instead. Ultimately,
all code related to it that isn't in the target triple parser was removed. It
seems to be a real product, just... literally no one seems to know anything
about the ISA. I figure after almost a decade with no public ISA documentation
to speak of, and no LLVM backend to reference, it's probably safe to assume that
we're not going to learn much about this ISA, making it useless for Zig.
See: 1b5767f72b
See: 84a7564b28
See: 8cfe9d8f2a
Remove --debug-incremental
This flag is also added to the build system. Importantly, this tells
Compile step whether or not to keep the compiler running between
rebuilds. It defaults off because it is currently crashing
zirUpdateRefs.
This allows the mutate mutex to only be locked during actual grows,
which are rare. For the lists that didn't previously have a mutex, this
change has little effect since grows are rare and there is zero
contention on a mutex that is only ever locked by one thread. This
change allows `extra` to be mutated without racing with a grow.
