This is supposed to be the case, similar to how pointers to generic
functions are comptime-only (several pieces of logic already assumed
this). These types being considered runtime was causing `dbg_var_val`
AIR instructions to be wrongly emitted for such values, causing codegen
backends to create a runtime reference to the inline function, which (at
least on the LLVM backend) triggers an error.
Resolves: #38
This change implements the following syntax into the compiler:
```zig
const x: u32, var y, foo.bar = .{ 1, 2, 3 };
```
A destructure expression may only appear within a block (i.e. not at
comtainer scope). The LHS consists of a sequence of comma-separated var
decls and/or lvalue expressions. The RHS is a normal expression.
A new result location type, `destructure`, is used, which contains
result pointers for each component of the destructure. This means that
when the RHS is a more complicated expression, peer type resolution is
not used: each result value is individually destructured and written to
the result pointers. RLS is always used for destructure expressions,
meaning every `const` on the LHS of such an expression creates a true
stack allocation.
Aside from anonymous array literals, Sema is capable of destructuring
the following types:
* Tuples
* Arrays
* Vectors
A destructure may be prefixed with the `comptime` keyword, in which case
the entire destructure is evaluated at comptime: this means all `var`s
in the LHS are `comptime var`s, every lvalue expression is evaluated at
comptime, and the RHS is evaluated at comptime. If every LHS is a
`const`, this is not allowed: as with single declarations, the user
should instead mark the RHS as `comptime`.
There are a few subtleties in the grammar changes here. For one thing,
if every LHS is an lvalue expression (rather than a var decl), a
destructure is considered an expression. This makes, for instance,
`if (cond) x, y = .{ 1, 2 };` valid Zig code. A destructure is allowed
in almost every context where a standard assignment expression is
permitted. The exception is `switch` prongs, which cannot be
destructures as the comma is ambiguous with the end of the prong.
A follow-up commit will begin utilizing this syntax in the Zig compiler.
Resolves: #498
The `coerce_result_ptr` instruction is highly problematic and leads to
unintentional memory reinterpretation in some cases. It is more correct
to simply not forward result pointers through this builtin.
`coerce_result_ptr` is still used for struct and array initializations,
where it can still cause issues. Eliminating this usage will be a future
change.
Resolves: #16991
The following cast builtins did not previously work on vectors, and have
been made to:
* `@floatCast`
* `@ptrFromInt`
* `@intFromPtr`
* `@floatFromInt`
* `@intFromFloat`
* `@intFromBool`
Resolves: #16267
`TailQueue` was implemented as a doubly-linked list, but named after an
abstract data type. This was inconsistent with `SinglyLinkedList`, which
can be used to implement an abstract data type, but is still named after
the implementation. Renaming `TailQueue` to `DoublyLinkedList` improves
consistency between the two type names, and should help discoverability.
`TailQueue` is now a deprecated alias of `DoublyLinkedList`.
Related to issues #1629 and #8233.
There are a couple concepts here worth understanding:
Key.UnionType - This type is available *before* resolving the union's
fields. The enum tag type, number of fields, and field names, field
types, and field alignments are not available with this.
InternPool.UnionType - This one can be obtained from the above type with
`InternPool.loadUnionType` which asserts that the union's enum tag type
has been resolved. This one has all the information available.
Additionally:
* ZIR: Turn an unused bit into `any_aligned_fields` flag to help
semantic analysis know whether a union has explicit alignment on any
fields (usually not).
* Sema: delete `resolveTypeRequiresComptime` which had the same type
signature and near-duplicate logic to `typeRequiresComptime`.
- Make opaque types not report comptime-only (this was inconsistent
between the two implementations of this function).
* Implement accepted proposal #12556 which is a breaking change.
* Generalise NaN handling and make std.math.nan() give quiet NaNs
* Address uses of std.math.qnan_* and std.math.nan_* consts
* Comment out failing test due to issues with signalling NaN
* Fix issue in c_builtins.zig where we need qnan_u32
as explainded at https://llvm.org/docs/LangRef.html#vector-type :
"In general vector elements are laid out in memory in the same way as array types.
Such an analogy works fine as long as the vector elements are byte sized.
However, when the elements of the vector aren’t byte sized it gets a bit more complicated.
One way to describe the layout is by describing what happens when a vector such
as <N x iM> is bitcasted to an integer type with N*M bits, and then following the
rules for storing such an integer to memory."
"When <N*M> isn’t evenly divisible by the byte size the exact memory layout
is unspecified (just like it is for an integral type of the same size)."
AstGen provides all function call arguments with a result location,
referenced through the call instruction index. The idea is that this
should be the parameter type, but for `anytype` parameters, we use
generic poison, which is required to be handled correctly.
Previously, generic instantiations and inline calls worked by evaluating
all args in advance, before resolving generic parameter types. This
means any generic parameter (not just `anytype` ones) had generic poison
result types. This caused missing result locations in some cases.
Additionally, the generic instantiation logic caused `zirParam` to
analyze the argument types a second time before coercion. This meant
that for nominal types (struct/enum/etc), a *new* type was created,
distinct to the result type which was previously forwarded to the
argument expression.
This commit fixes both of these issues. Generic parameter type
resolution is now interleaved with argument analysis, so that we don't
have unnecessary generic poison types, and generic instantiation logic
now handles parameters itself rather than falling through to the
standard zirParam logic, so avoids duplicating the types.
Resolves: #16566Resolves: #16258Resolves: #16753
Well, this was a journey!
The original issue I was trying to fix is covered by the new behavior
test in array.zig: in essence, `ty` and `coerced_ty` result locations
were not correctly propagated.
While fixing this, I noticed a similar bug in struct inits: the type was
propagated to *fields* fine, but the actual struct init was
unnecessarily anonymous, which could lead to unnecessary copies. Note
that the behavior test added in struct.zig was already passing - the bug
here didn't change any easy-to-test behavior - but I figured I'd add it
anyway.
This is a little harder than it seems, because the result type may not
itself be an array/struct type: it could be an optional / error union
wrapper. A new ZIR instruction is introduced to unwrap these.
This is also made a little tricky by the fact that it's possible for
result types to be unknown at the time of semantic analysis (due to
`anytype` parameters), leading to generic poison. In these cases, we
must essentially downgrade to an anonymous initialization.
Fixing these issues exposed *another* bug, related to type resolution in
Sema. That issue is now tracked by #16603. As a temporary workaround for
this bug, a few result locations for builtin function operands have been
disabled in AstGen. This is technically a breaking change, but it's very
minor: I doubt it'll cause any breakage in the wild.
This function does not seem to differ in any interesting way from
`!typeRequiresComptime`, other than the `is_extern` param which is only
used in one place, and some differences did not seem correct anyway.
My reasoning for changing opaque types to be comptime-only is that
`explainWhyTypeIsComptime` is quite happy to explain why they are. :D
After fixing some issues with inline assembly in the C backend, the std
cleanups have the side effect of making these functions compatible with
the backend, allowing it to be used on linux without linking libc.
This change allows the following types to appear in extern structs:
* Zero-bit integers
* void
* zero-sized structs and packed structs
* enums with zero-bit backing integers
* arrays of any length with zero-size elements
When acessing a packed struct member via a byte aligned ptr (from the optimisation in Sema.structFieldPtrByIndex())
the codegen must apply the parent ptr packed_offset in addition to the field offset itself.
resolves https://github.com/ziglang/zig/issues/16609
This commit does two things which seem unrelated at first, but,
together, solve a miscompilation, and potentially slightly speed up
compiler perf, at the expense of making #2765 trickier to implement in
the future.
Sema: avoid returning a false positive for whether an inferred error set
is comptime-known to be empty.
AstGen: mark function calls as not being interested in a result
location. This prevents the test case "ret_ptr doesn't cause own
inferred error set to be resolved" from being regressed. If we want to
accept and implement #2765 in the future, it will require solving this
problem a different way, but the principle of YAGNI tells us to go ahead
with this change.
Old ZIR looks like this:
%97 = ret_ptr()
%101 = store_node(%97, %100)
%102 = load(%97)
%103 = ret_is_non_err(%102)
New ZIR looks like this:
%97 = ret_type()
%101 = as_node(%97, %100)
%102 = ret_is_non_err(%101)
closes#15669
The special case to take advantage of llvm's intrinsic
was generating invalid llvm ir:
```
Invalid bitcast
%60 = bitcast <2 x i2> %59 to i8, !dbg !3122
thread 145453 panic: LLVM module verification failed
```
fixes#10731
Thanks @nektro for previous work in #14878
This change creates a small breaking change:
It removes the `is_pub` field of a decl in `@typeInfo`
When a signed integer's bitsize is not 32 or 64, but the given
bitsize and wanted bitsize are either both represented by Wasm's i32
or i64, we must either sign extend or wrap the integer.
