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>
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 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.
Co-authored-by: Motiejus Jakštys <motiejus@jakstys.lt>
Co-authored-by: Jakub Konka <kubkon@jakubkonka.com>
Co-authored-by: Samuel Cantero <scanterog@gmail.com>
Co-authored-by: Giorgos Georgiou <giorgos.georgiou@datadoghq.com>
Co-authored-by: Carl Åstholm <carl@astholm.se>
This branch introduced an arena allocator for temporary allocations in
Compilation.update. Almost every implementation of flush() inside the
linker code was already creating a local arena that had the lifetime of
the function call. This commit passes the update arena so that all those
local ones can be deleted, resulting in slightly more efficient memory
usage with every compilation update.
While at it, this commit also removes the Compilation parameter from the
linker flush function API since a reference to the Compilation is now
already stored in `link.File`.
Now, link.File will always be null when -fno-emit-bin is specified, and
in the case that LLVM artifacts are still required, the Zcu instance has
an LlvmObject.
* move wasi_emulated_libs into Compilation
- It needs to be accessed from Compilation, which needs to potentially
build those artifacts.
* Compilation: improve error reporting for two cases
- the setMiscFailure mechanism is handy - let's use it!
* fix one instance of incorrectly checking for emit_bin via
`comp.bin_file != null`. There are more instances of this that need to
be fixed in a future commit.
* fix renameTmpIntoCache not handling the case where it needs to make
the "o" directory in the zig-cache directory.
- while I'm at it, simplify the logic for handling the fact that
Windows returns error.AccessDenied rather than
error.PathAlreadyExists for failure to rename a directory over
another one.
* fix missing cache hash additions
- there are still more to add in a future commit -
addNonIncrementalStuffToCacheManifest is called when bin_file is
always null, and then it incorrectly checks if bin_file is non-null
and only then adds a bunch of stuff to the cache hash. It needs to
instead add to the cache hash based on lf_open_opts.
This is necessary because on COFF, the entry symbol name is not known
until the linker has looked at the set of global symbol names to
determine which of the four possible main entry points is present.
implement builtin.zig file population for all modules rather than
assuming there is only one global builtin.zig module.
move some fields from link.File to Compilation
move some fields from Module to Compilation
compute debug_format in global Compilation config resolution
wire up C compilation to the concept of owner modules
make whole cache mode call link.File.createEmpty() instead of
link.File.open()
