Previously, the `load` instruction would just pass the pointer to the next instruction
for types that comply to `isByRef`. However, this meant that a defer would directly write
to the reference, rather than a copy. After this commit, we always copy the value.
- This implements all pointer arithmetic related instructions such as ptr_add, ptr_sub, ptr_elem_val
- We refactored the code, to use `isByRef` to ensure consistancy.
- Pointers will now be loaded correctly, rather then being passed around.
- The behaviour test for pointers is now passing.
- Previously the table index and function type index were switched.
This commit swaps them.
- This also emits the correct indirect function calls count when importing the function table
- Add method to easily create local for virtual stack
- Ensure function pointers are passed correctly
- Correctly handle slices as return types and values
- Fix wrapping error sets/payloads.
- Handle ptr-like optionals correctly, by using address '0' as null.
- Implement `array_to_slice`
- linker: Always emit a table, so call_indirect inside bodies do not fail if there's no table.
TODO: Only do this when we emit a call_indirect but the relocation cannot be resolved.
* load address (pointer) to a stack variable in a register via
`lea` instruction
* store value on the stack via a pointer stored in a register via
`mov [reg], imm` instruction
* the lowerings naturally are handled automatically by Mir -> Isel
layer
* add initial (without safety) implementation of `.optional_payload`
* add matching stage2 test cases
Effectively a small continuation of #10152
This allows the for.zig behavior tests to pass. Unfortunately to fully test everything I had to move a lot of behavior tests from array.zig; most of them now pass (sorry @rainbowbismuth!)
I'm also conflicted on how I store constants into arrays because it's kind of stupid; array's can't be re-initialized using the same syntax, so instead of initializing each element, a new array is made which is copied into the destination. This also required that renderValue can't emit string literals for byte arrays given that they need to always have an extra byte for the NULL terminator, meaning that strings are no longer grep-able in the output.
* fix handling of `ah`, `bh`, `ch`, and `dh` registers (which are
actually used as aliases to `dil`, etc. registers). Currenly, we
treat them as aliases only meaning when we encounter `ah` we make
sure to set the REX.W to promote the instruction to 64bits and use
`dil` register instead - otherwise we might have mismatch between
registers used in different parts of the codegen. In the future,
we can and should use `ah`, etc. as upper 8bit halves of 16bit
registers `ax`, etc.
* fix bug in `airCmp` where `.cmp` MIR instruction shouldn't force
type `Bool` but let the type of the original type propagate downwards
- we need this to make an informed choice of the target register
size and hence choose the right encoding down the line.
* implement lowering of 1-byte and 2-byte values to stack and add
matching stage2 tests for x86_64 codegen
* `Module.Union.getLayout`: fixes to support components of the union
being 0 bits.
* Implement `@typeInfo` for unions.
* Add missing calls to `resolveTypeFields`.
* Fix explicitly-provided union tag types passing a `Zir.Inst.Ref`
where an `Air.Inst.Ref` was expected. We don't have any type safety
for this; these typess are aliases.
* Fix explicitly-provided `union(enum)` tag Values allocated to the
wrong arena.
* reduce number of branches in zirCmpEq
* implement equality comparison for enums and unions
* fix coercion from union to its tag type resulting in the wrong type
* fix method calls of unions
* implement peer type resolution for unions, enums, and enum literals
* fix union tag type memory in the wrong arena
Comment from this commit reproduced here:
LLVM does not allow us to change the type of globals. So we must
create a new global with the correct type, copy all its attributes,
and then update all references to point to the new global,
delete the original, and rename the new one to the old one's name.
This is necessary because LLVM does not support const bitcasting
a struct with padding bytes, which is needed to lower a const union value
to LLVM, when a field other than the most-aligned is active. Instead,
we must lower to an unnamed struct, and pointer cast at usage sites
of the global. Such an unnamed struct is the cause of the global type
mismatch, because we don't have the LLVM type until the *value* is created,
whereas the global needs to be created based on the type alone, because
lowering the value may reference the global as a pointer.
* fix initialisation of void* fields of structs (initialises to 0xaa.. rather than {})
* don't generate struct fields when the field type does not have codegen bits
* in airAlloc generate a void* literal if the element type does not have codegen bits
The main problem was that the loop body was treated as an expression
that was one of the peer result values of a loop, when in reality the
loop body is noreturn and only the `break` operands are the result
values of loops.
This was solved by introducing an override that prevents rvalue() from
emitting a store to result location instruction for loop bodies.
An orthogonal change also included in this commit is switching
`elem_val` index expressions to using `coerced_ty` and doing the
coercion to `usize` inside `Sema`, resulting in smaller ZIR (since the
cast becomes implied).
I also changed the break operand expression to use `reachableExpr`,
introducing a new compile error for double break.
This makes a few more behavior tests pass for `while` and `for` loops.
Introduced a new AIR instruction: `tag_name`. Reasons to do this
instead of lowering it in Sema to a switch, function call, array
lookup, or if-else tower:
* Sema is a bottleneck; do less work in Sema whenever possible.
* If any optimization passes run, and the operand to becomes
comptime-known, then it could change to have a comptime result
value instead of lowering to a function or array or something which
would then have to be garbage-collected.
* Backends may want to choose to use a function and a switch branch,
or they may want to use a different strategy.
Codegen for `@tagName` is implemented for the LLVM backend but not any
others yet.
Introduced some new `Type` tags:
* `const_slice_u8_sentinel_0`
* `manyptr_const_u8_sentinel_0`
The motivation for this was to make typeof() on the tag_name AIR
instruction non-allocating.
A bunch more enum tests are passing now.
* remove false positive "all prongs handled" compile error for
non-exhaustive enums.
* implement `@TypeInfo` for enums, except enums which have any
declarations is still TODO.
* `getBuiltin` uses nomespaceLookup/analyzeDeclVal rather than
namespaceLookupRef/analyzeLoad. Avoids a detour through an
unnecessary type, and adds a detour through a caching mechanism.
* `Value.eql`: add missing code to handle enum comparisons for
non-exhaustive enums. It works by converting the enum tags to numeric
values and comparing those.
Layout algorithm: all `align(0)` fields are squished together as if they
were a single integer with a number of bits equal to `@bitSizeOf` each
field added together. Then the natural ABI alignment of that integer is
used for that pseudo-field.
Previously, this function would return an incorrect result for structs
and unions which did not have their fields resolved yet.
This required introducing more logic in Sema to resolve types before
doing certain things such as creating an anonmyous Decl and emitting
function call AIR.
As a result a couple more struct tests pass.
Oh, and I implemented the language change to make sizeOf for pointers
always return pointer size bytes even if the element type is 0 bits.
* Extract common logic between `zirStructInitEmpty` and
`zirStructInit`.
* `resolveTypeFields` additionally sets status to `have_layout` if the
total number of fields is 0.
