This type is exactly the same as std.Build.Cache.Path, except for
one function which is not used anymore. Therefore we can replace
it without consequences.
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>
Primarily, this commit removes 2 fields from File, relying on the data
being stored in the `files` field, with the key as the path digest, and
the value as the struct decl corresponding to the File. This table is
serialized into the compiler state that survives between incremental
updates.
Meanwhile, the File struct remains ephemeral data that can be
reconstructed the first time it is needed by the compiler process, as
well as operated on by independent worker threads.
A key outcome of this commit is that there is now a stable index that
can be used to refer to a File. This will be needed when serializing
error messages to survive incremental compilation updates.
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.
`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`.
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`.
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()
These options are only supposed to be provided to the initialization
functions, resolved, and then computed values stored in the appropriate
place (base struct or the object-format-specific structs).
Many more to go...
This reverts commit 7161ed79c4abcaccdd56fe0b4fbd3d93472d41b8, reversing
changes made to 3f2a65594e1d3c0a4f4943a4ea522e8405db81e0.
Unfortunately, this sat in the PR queue too long and the merge broke the
zig1.wasm bootstrap process.
The main motivating change here is to prevent the creation of a fake
Decl object by the frontend in order to `@export()` a value.
Instead, `link.updateDeclExports` is renamed to `link.updateExports` and
accepts a tagged union which can be either a Decl.Index or a
InternPool.Index.
Commit 5393e56500d499753dbc39704c0161b47d1e4d5c has a flaw pointed out
by @mlugg: the `ty` field of pointer values changes when comptime values
are pointer-casted. This commit introduces a new encoding which
additionally stores the "original pointer type" which is used to store
the alignment of the anonymous decl, and potentially other information
in the future such as section and pointer address space. However, this
new encoding is only used when the original pointer type differs from
the casted pointer type in a meaningful way.
I was able to make the LLVM backend and the C backend lower anonymous
decls with the appropriate alignment, however I will need some help
figuring out how to do this for the backends that lower anonymous decls
via src/codegen.zig and the wasm backend.
Introduce the new mechanism needed to render anonymous decls to C code
that the frontend is now using.
The current strategy is to collect the set of used anonymous decls into
one ArrayHashMap for the entire compilation, and then render them during
flush().
In the future this may need to be adjusted for incremental compilation
purposes, so that removing a Decl from decl_table means that newly
unused anonymous decls are no longer rendered. However, let's do one
thing at a time. The only goal of this branch is to stop using
Module.Decl objects for unnamed constants.
Start keeping track of dependencies on anon decls for dependency
ordering during flush()
Currently this causes use of undefined symbols because these
dependencies need to get rendered into the output.
When the compiler's state lives through multiple Compilation.update()
calls, the C backend stores the rendered C source code for each
decl code body and forward declarations.
With this commit, the state is still stored, but it is managed in one
big array list in link/C.zig rather than many array lists, one for each
decl. This means simpler serialization and deserialization.
Abridged summary:
* Move `Module.Fn` into `InternPool`.
* Delete a lot of confusing and problematic `Sema` logic related to
generic function calls.
This commit removes `Module.Fn` and replaces it with two new
`InternPool.Tag` values:
* `func_decl` - corresponding to a function declared in the source
code. This one contains line/column numbers, zir_body_inst, etc.
* `func_instance` - one for each monomorphization of a generic
function. Contains a reference to the `func_decl` from whence the
instantiation came, along with the `comptime` parameter values (or
types in the case of `anytype`)
Since `InternPool` provides deduplication on these values, these fields
are now deleted from `Module`:
* `monomorphed_func_keys`
* `monomorphed_funcs`
* `align_stack_fns`
Instead of these, Sema logic for generic function instantiation now
unconditionally evaluates the function prototype expression for every
generic callsite. This is technically required in order for type
coercions to work. The previous code had some dubious, probably wrong
hacks to make things work, such as `hashUncoerced`. I'm not 100% sure
how we were able to eliminate that function and still pass all the
behavior tests, but I'm pretty sure things were still broken without
doing type coercion for every generic function call argument.
After the function prototype is evaluated, it produces a deduplicated
`func_instance` `InternPool.Index` which can then be used for the
generic function call.
Some other nice things made by this simplification are the removal of
`comptime_args_fn_inst` and `preallocated_new_func` from `Sema`, and the
messy logic associated with them.
I have not yet been able to measure the perf of this against master
branch. On one hand, it reduces memory usage and pointer chasing of the
most heavily used `InternPool` Tag - function bodies - but on the other
hand, it does evaluate function prototype expressions more than before.
We will soon find out.
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
These are frequently invalidated whenever a string is interned, so avoid
creating pointers to `string_bytes` wherever possible. This is an
attempt to fix random CI failures.
The main motivation for this commit is eliminating Decl.value_arena.
Everything else is dominoes.
Decl.name used to be stored in the GPA, now it is stored in InternPool.
It ended up being simpler to migrate other strings to be interned as
well, such as struct field names, union field names, and a few others.
This ended up requiring a big diff, sorry about that. But the changes
are pretty nice, we finally start to take advantage of InternPool's
existence.
global_error_set and error_name_list are simplified. Now it is a single
ArrayHashMap(NullTerminatedString, void) and the index is the error tag
value.
Module.tmp_hack_arena is re-introduced (it was removed in
eeff407941560ce8eb5b737b2436dfa93cfd3a0c) in order to deal with
comptime_args, optimized_order, and struct and union fields. After
structs and unions get moved into InternPool properly, tmp_hack_arena
can be deleted again.
