When analyzing the `validate_ref_ty` ZIR instruction, an assertion would
trip if the result type was a var args function argument. The fix is the
same as e6b73be870a39f4da7a08a40da23e38b5e9613da - inline the logic of
`resolveType` and handle the case of var args.
Closes#17494
When analyzing the `as` ZIR instruction, an assertion would trip if the
result type was a var args function argument. The fix is simple: inline
a little bit of the `resolveType` logic into `analyzeAs` to make it
detect this situation - which it was already attempting to do.
Closes#16197
The following pairs of functions have been combined using the "advanced"
pattern used for other type queries:
* `Sema.fnHasRuntimeBits`, `Type.isFnOrHasRuntimeBits`
* `Sema.typeRequiresComptime`, `Type.comptimeOnly`
* add Module instances for each package's build.zig and attach it to the
dependencies.zig module with the hash digest hex string as the name.
* fix incorrectly skipping the wrong packages for creating
dependencies.zig
* a couple more renaming of "package" to "module"
Finish the work started in 4c4fb839972f66f55aa44fc0aca5f80b0608c731.
Now the compiler compiles again.
Wire up dependency tree fetching code in the CLI for `zig build`.
Everything is hooked up except for `createDependenciesModule` is not yet
implemented.
Instead of explicitly creating a `Module.Decl` object for each anonymous
declaration, each `InternPool.Index` value is implicitly understood to
be an anonymous declaration when encountered by backend codegen.
The memory management strategy for these anonymous decls then becomes to
garbage collect them along with standard InternPool garbage.
In the interest of a smooth transition, this commit only implements this
new scheme for string literals and leaves all the previous mechanisms in
place.
My previous change for reading / writing to unions at comptime did not handle
union field read/writes correctly in all cases. Previously, if a field was
written to a union, it would overwrite the entire value. This is problematic
when a field of a larger size is subsequently read, because the value would not
be long enough, causing a panic.
Additionally, the writing behaviour itself was incorrect. Writing to a field of
a packed or extern union should only overwrite the bits corresponding to that
field, allowing for memory reintepretation via field writes / reads.
I addressed these problems as follows:
Add the concept of a "backing type" for extern / packed unions
(`Type.unionBackingType`). For extern unions, this is a `u8` array, for packed
unions it's an integer matching the `bitSize` of the union. Whenever union
memory is read at comptime, it's read as this type.
When union memory is written at comptime, the tag may still be known. If so, the
memory is written using the tagged type. If the tag is unknown (because this
union had previously been read from memory), it's simply written back out as the
backing type.
I added `write_packed` to the `reinterpret` field of
`ComptimePtrMutationKit`. This causes writes of the operand to be packed - which
is necessary when writing to a field of a packed union. Without this, writing a
value to a `u1` field would overwrite the entire byte it occupied.
The final case to address was reading a different (potentially larger) field
from a union when it was written with a known tag. To handle this, a new kind of
bitcast was introduced (`bitCastUnionFieldVal`) which supports reading a larger
field by using a backing buffer that has the unwritten bits set to
undefined. The reason to support this (vs always just writing the union as it's
backing type), is that no reads to larger fields ever occur at comptime, it
would be strictly worse to have spent time writing the full backing type.
This reverts commit 21780899eb17a0cb795ff40e5fae6556c38ea13e.
After this commit, a version of the compiler which supports the new
`@abs` builtin is required.
Instead of linear search every time a packed struct field's bit or byte
offset is wanted, they are computed once during resolution of the packed
struct's backing int type, and stored in InternPool for O(1) lookup.
Closes#17178
This commit introduces the new `ref_coerced_ty` result type into AstGen.
This represents a expression which we want to treat as an lvalue, and
the pointer will be coerced to a given type.
This change gives known result types to many expressions, in particular
struct and array initializations. This allows certain casts to work
which previously required explicitly specifying types via `@as`. It also
eliminates our dependence on anonymous struct types for expressions of
the form `&.{ ... }` - this paves the way for #16865, and also results
in less Sema magic happening for such initializations, also leading to
potentially better runtime code.
As part of these changes, this commit also implements #17194 by
disallowing RLS on explicitly-typed struct and array initializations.
Apologies for linking these changes - it seemed rather pointless to try
and separate them, since they both make big changes to struct and array
initializations in AstGen. The rationale for this change can be found in
the proposal - in essence, performing RLS whilst maintaining the
semantics of the intermediary type is a very difficult problem to solve.
This allowed the problematic `coerce_result_ptr` ZIR instruction to be
completely eliminated, which in turn also simplified the logic for
inferred allocations in Sema - thanks to this, we almost break even on
line count!
In doing this, the ZIR instructions surrounding these initializations
have been restructured - some have been added and removed, and others
renamed for clarity (and their semantics changed slightly). In order to
optimize ZIR tag count, the `struct_init_anon_ref` and
`array_init_anon_ref` instructions have been removed in favour of using
`ref` on a standard anonymous value initialization, since these
instructions are now virtually never used.
Lastly, it's worth noting that this commit introduces a slightly strange
source of generic poison types: in the expression `@as(*anyopaque, &x)`,
the sub-expression `x` has a generic poison result type, despite no
generic code being involved. This turns out to be a logical choice,
because we don't know the result type for `x`, and the generic poison
type represents precisely this case, providing the semantics we need.
Resolves: #16512Resolves: #17194
When the tag is not known, it's set to `.none`. In this case, the value is either an
array of bytes (for extern unions) or an integer (for packed unions).
This was previously implemented by analyzing the AIR prior to the ZIR
`make_ptr_const` instruction. This solution was highly delicate, and in
particular broke down whenever there was a second `alloc` between the
`store` and `alloc` instructions, which is especially common in
destructure statements.
Sema now uses a different strategy to detect whether a `const` is
comptime-known. When the `alloc` is created, Sema begins tracking all
pointers and stores which refer to that allocation in temporary local
state. If any store is not comptime-known or has a higher runtime index
than the allocation, the allocation is marked as being runtime-known.
When we reach the `make_ptr_const` instruction, if the allocation is not
marked as runtime-known, it must be comptime-known. Sema will use the
set of `store` instructions to re-initialize the value in comptime
memory. We optimize for the common case of a single `store` instruction
by not creating a comptime alloc in this case, instead directly plucking
the result value from the instruction.
Resolves: #16083
Previously, @memset at comptime performed N pointer stores. This is less
efficient than just storing a whole array of values at once. The
difference can be quite drastic when reinterpreting memory - a test case
which is 40s on master branch now takes under a second on a debug
compiler build.
Resolves: #17214
When struct types have no field names, the names are implicitly
understood to be strings corresponding to the field indexes in
declaration order. It used to be the case that a NullTerminatedString
would be stored for each field in this case, however, now, callers must
handle the possibility that there are no names stored at all. This
commit introduces `legacyStructFieldName`, a function to fake the
previous behavior. Probably something better could be done by reworking
all the callsites of this function.
This changeset fixes the handling of alignment in several places. The
new rules are:
* `@alignOf(T)` where `T` is a runtime zero-bit type is at least 1,
maybe greater.
* Zero-bit fields in `extern` structs *do* force alignment, potentially
offsetting following fields.
* Zero-bit fields *do* have addresses within structs which can be
observed and are consistent with `@offsetOf`.
These are not necessarily all implemented correctly yet (see disabled
test), but this commit fixes all regressions compared to master, and
makes one new test pass.
Previously it would canonicalize or not depending on some volatile
internal state of the compiler, now it forces resolution of the element
type to determine the alignment if it needs to.
