This replaces the constant `Zir.Inst.Ref` tags (and the analagous tags
in `Air.Inst.Ref`, `InternPool.Index`) referring to types in
`std.builtin` with a ZIR instruction `extended(builtin_type(...))` which
instructs Sema to fetch such a type, effectively as if it were a
shorthand for the ZIR for `@import("std").builtin.xyz`.
Previously, this was achieved through constant tags in `Ref`. The
analagous `InternPool` indices began as `simple_type` values, and were
later rewritten to the correct type information. This system was kind of
brittle, and more importantly, isn't compatible with incremental
compilation of std, since incremental compilation relies on the ability
to recreate types at different indices when they change. Replacing the
old system with this instruction slightly increases the size of ZIR, but
it simplifies logic and allows incremental compilation to work correctly
on the standard library.
This shouldn't have a significant impact on ZIR size or compiler
performance, but I will take measurements in the PR to confirm this.
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.
This function now has to allocate anyway to resolve references, so we
may as well just build the error bundle and check its length.
Also remove some unnecessary calls of this function for efficiency.
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.
When a type becomes outdated, there will still be lingering references
to the old index -- for instance, any declaration whose value was that
type holds a reference to that index. These references may live for an
arbitrarily long time in some cases. So, we can't just remove the type
from the pool -- the old `Index` must remain valid!
Instead, we want to preserve the old `Index`, but avoid it from ever
appearing in lookups. (It's okay if analysis of something referencing
the old `Index` does weird stuff -- such analysis are guaranteed by the
incremental compilation model to always be unreferenced.) So, we use the
new `InternPool.putKeyReplace` to replace the shard entry for this index
with the newly-created index.
An enum type is kind of like a struct or union type, in that field
errors are happening during type resolution. The only difference is that
type resolution happens at the time the type is created. So, errors in
fields should not cause the type to be deleted: we've already added a
reference entry, and incremenetal dependencies which must be invalidated
if the compile error is fixed. Once we call `WipEnumType.prepare`, we
should never call `WipEnumType.cancel`. This is analagous to logic for
enum declarations in `Sema.zirEnumDecl`.
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.
This fixes the failure to find CLANG_LIBRARIES on debian, which packages
the relevant .so file at these paths:
libclang-cpp18: /usr/lib/llvm-18/lib/libclang-cpp.so.18.1
libclang-cpp18: /usr/lib/x86_64-linux-gnu/libclang-cpp.so.18.1
libclang-cpp18: /usr/lib/x86_64-linux-gnu/libclang-cpp.so.18
(The latter two paths are symlinks to the first.)
