There are some differences vs. the union encoding in the LLVM backend:
- Tagged unions with a 0-bit payload do not become their tag type. Instead,
they are a struct with an empty `union` as their payload field.
- We do not order the `payload`/`tag` storage based on their alignment
There are some restrictions here.
- We either need C11 or a compiler that supports the aligned attribute
- We cannot provide align less than the type's natural C alignment.
In the behavior test listings, I had to move type_info.zig test import
to a section that did not include the x86 backend because it got to the
point where adding another test to the file, even if it was an empty
test that just returned immediately, caused a runtime failure when
executing the test binary.
Anyway, type info for opaques is implemented, and the declarations slice
is shared between it, enums, and unions.
Still TODO is the `data` field of a `Declaration`. I want to consider
removing it from the data returned from `@typeInfo` and introducing
`@declInfo` or similar for this data. This would avoid the complexity of
a lazy mechanism.
The ZIR instructions `switch_capture_else` and `switch_capture_ref` are
removed because they are not needed. Instead, the prong index is set to
max int for the special prong.
Else prong with error sets is not handled yet.
Adds a new behavior test because there was not a prior on to cover only
the capture value of else on a switch.
* implement `genSetStack` for `ptr_stack_offset`
* handle `ptr_add`
* implement storing from register into pointer in register
* split alignment and array tests into those that pass on x86_64 and
those that do not
* pass more tests on x86_64
Add a variant of the `validate_struct_init` ZIR instruction:
`validate_struct_init_comptime` which is the same thing except it
indicates a comptime scope.
Sema code for this instruction now handles default struct field
values and detects when the struct initialization resulted in a
comptime value, replacing the already-emitted AIR instructions
to store each individual field with a single `store` instruction
with a comptime struct value as the operand.
In the case of a comptime scope, there is a simpler path that only
evals the implicit store instructions for default field values, avoiding
the mechanism for detecting comptime values.
This regressed one test case for the wasm backend, but it's just hitting
a different prong of `emitConstant` which currently has "TODO" in there,
so I think it's fine.
This allows Zig code to perform conditional compilation based on a tag
by which a Zig compiler implementation identifies itself.
See the doc comment in this commit for more details.
We now detect if the return type will be set by passing the first argument
as a pointer to stack memory from the callee's frame. This way, we do not have to
worry about stack memory being overwritten.
Besides this, we implement memset by either using wasm's memory.fill instruction when available,
or lower it manually. In the future we can lower this to a compiler_rt call.
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.
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 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.
