This commit enhances AstGen to introduce a form of error resilience
which allows valid ZIR to be emitted even when AstGen errors occur.
When a non-fatal AstGen error (e.g. `appendErrorNode`) occurs, ZIR
generation is not affected; the error is added to `astgen.errors` and
ultimately to the errors stored in `extra`, but that doesn't stop us
getting valid ZIR. Fatal AstGen errors (e.g. `failNode`) are a bit
trickier. These errors return `error.AnalysisFail`, which is propagated
up the stack. In theory, any parent expression can catch this error and
handle it, continuing ZIR generation whilst throwing away whatever was
lost. For now, we only do this in one place: when creating declarations.
If a call to `fnDecl`, `comptimeDecl`, `globalVarDecl`, etc, returns
`error.AnalysisFail`, the `declaration` instruction is still created,
but its body simply contains the new `extended(astgen_error())`
instruction, which instructs Sema to terminate semantic analysis with a
transitive error. This means that a fatal AstGen error causes the
innermost declaration containing the error to fail, but the rest of the
file remains intact.
If a source file contains parse errors, or an `error.AnalysisFail`
happens when lowering the top-level struct (e.g. there is an error in
one of its fields, or a name has multiple declarations), then lowering
for the entire file fails. Alongside the existing `Zir.hasCompileErrors`
query, this commit introduces `Zir.loweringFailed`, which returns `true`
only in this case.
The end result here is that files with AstGen failures will almost
always still emit valid ZIR, and hence can undergo semantic analysis on
the parts of the file which are (from AstGen's perspective) valid. This
is a noteworthy improvement to UX, but the main motivation here is
actually incremental compilation. Previously, AstGen failures caused
lots of semantic analysis work to be thrown out, because all `AnalUnit`s
in the file required re-analysis so as to trigger necessary transitive
failures and remove stored compile errors which would no longer make
sense (because a fresh compilation of this code would not emit those
errors, as the units those errors applied to would fail sooner due to
referencing a failed file). Now, this case only applies when a file has
severe top-level errors, which is far less common than something like
having an unused variable.
Lastly, this commit changes a few errors in `AstGen` to become fatal
when they were previously non-fatal and vice versa. If there is still a
reasonable way to continue AstGen and lower to ZIR after an error, it is
non-fatal; otherwise, it is fatal. For instance, `comptime const`, while
redundant syntax, has a clear meaning we can lower; on the other hand,
using an undeclared identifer has no sane lowering, so must trigger a
fatal error.
/home/alexrp/.cache/zig/b/18236e302af25e3fb99bc6a232ddc447/builtin.zig:6:5: error: TODO (SPIR-V): Implement unsigned composite int type of 64 bits
pub const zig_backend = std.builtin.CompilerBackend.stage2_spirv64;
~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
These cases have been disabled for a while, and we have transitioned to
using a compact file format for incremental test cases.
I was originally planning to port all of these cases, but the vast
majority aren't testing anything interesting, so it wasn't worth the
effort. I did look through each one; anything interesting being tested
has been extracted into a new case in `test/incremental/`.
Two of the new tests are currently failing with the self-hosted ELF
linker, and thus are currently only enabled with the C backend.
Resolves: #12844
This commit reworks how anonymous struct literals and tuples work.
Previously, an untyped anonymous struct literal
(e.g. `const x = .{ .a = 123 }`) was given an "anonymous struct type",
which is a special kind of struct which coerces using structural
equivalence. This mechanism was a holdover from before we used
RLS / result types as the primary mechanism of type inference. This
commit changes the language so that the type assigned here is a "normal"
struct type. It uses a form of equivalence based on the AST node and the
type's structure, much like a reified (`@Type`) type.
Additionally, tuples have been simplified. The distinction between
"simple" and "complex" tuple types is eliminated. All tuples, even those
explicitly declared using `struct { ... }` syntax, use structural
equivalence, and do not undergo staged type resolution. Tuples are very
restricted: they cannot have non-`auto` layouts, cannot have aligned
fields, and cannot have default values with the exception of `comptime`
fields. Tuples currently do not have optimized layout, but this can be
changed in the future.
This change simplifies the language, and fixes some problematic
coercions through pointers which led to unintuitive behavior.
Resolves: #16865
Also, start using labeled switch statements when dispatching
maybe-runtime instructions like condbr to comptime-only variants like
condbr_inline.
This can't be merged until we get a zig1.wasm update due to #21385.
Resolves: #21405
The print order of error sets depends on the order that the compiler
adds names to its internal state. These names can be anything, and
do not necessarily need to be from the same error set or be errors
at all. When the last remaining reference to builtin.cpu.arch was
removed in start.zig in 9b42bc1ce5, this order changed. Likely there
is something that has the name 'C' that is referenced somewhere
recursively from builtin.cpu.arch.
This all causes these few tests to fail, and hence the expected
order is simply updated now. Perhaps there is a better way to
add this.
Under some architecture/operating system combinations it is forbidden
to return a pointer from a merge, as these pointers must point to a
location at compile time. This adds a check for those cases when
returning a pointer from a block merge.
This experimental target has no recent active maintainer. It's the only
linker backend complaining about this branch and I can't make sense of
the stack trace.
This can be fixed asynchronously by anyone who wants to maintain plan9
support. It does not need to block this branch.
although they would also pass simply reverted to master branch because
I made the deprecated API still work for now (to be removed after 0.14.0
is tagged)
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.
