Reorganize how the binOp and genBinOp functions work.
I've spent quite a while here reading exactly through the spec and so many
tests are enabled because of several critical issues the old design had.
There are some regressions that will take a long time to figure out individually
so I will ignore them for now, and pray they get fixed by themselves. When
we're closer to 100% passing is when I will start diving into them one-by-one.
what was happening is that instructions like `lb` were only affecting the lower bytes of the register and leaving the top dirty. this would lead to situtations were `cmp_eq` for example was using `xor`, which was failing because of the left-over stuff in the top of the register.
with this commit, we now zero out or truncate depending on the context, to ensure instructions like xor will provide proper results.
- implements `airSlice`, `airBitAnd`, `airBitOr`, `airShr`.
- got a basic design going for the `airErrorName` but for some reason it simply returns
empty bytes. will investigate further.
- only generating `.got.zig` entries when not compiling an object or shared library
- reduced the total amount of ops a mnemonic can have to 3, simplifying the logic
There is no way to know the expected parent pointer attributes (most
notably alignment) from the type of the field pointer, so provide them
in the first argument.
This change allows struct field inits to use layout information
of their own struct without causing a circular dependency.
`semaStructFields` caches the ranges of the init bodies in the `StructType`
trailing data. The init bodies are then resolved by `resolveStructFieldInits`,
which is called before the inits are actually required.
Within the init bodies, the struct decl's instruction is repurposed to refer
to the field type itself. This is to allow us to easily rebuild the inst_map
mapping required for the init body instructions to refer to the field type.
Thanks to @mlugg for the guidance on this one!
Use inline to vastly simplify the exposed API. This allows a
comptime-known endian parameter to be propogated, making extra functions
for a specific endianness completely unnecessary.
As suggested by mlugg, always returns `error.NeedLazy`. If this has a
performance impact, it could be replaced by adding lazy handling to
`comptimeOnlyAdvanced`.
This removes the strategy where union with different active
fields would be generated, and instead simply pointer casts
the active field type where required. This also allows removing
spv.ptrType and using self.ptrType instead, and allows caching
all union types (because there is only the canonical one).
This fixes a panic in `unionAbiSize` when a 0-length array of a union is used as a struct field.
Because `resolveTypeLayout` does not resolve the `elem_ty` if `arrayLenIncludingSentinel` returns
0 for the array, the child union type is not guaranteed to have a resolved layout at this point.
Fixed this case by just returning 0 here.
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
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.
