This fixes 2 entrypoints within the self-hosted wasm linker that would be called
for the llvm backend, whereas we should simply call into the llvm backend to perform such action.
i.e. not allocate a decl index when we have an llvm object, and when flushing a module,
we should be calling it on llvm's object, rather than have the wasm linker perform the operation.
Also, this fixes the wasm intrinsics for wasm.memory.size and wasm.memory.grow.
Lastly, this commit ensures that when an extern function is being resolved, we tell LLVM how
to import such function.
Like decl code generation, also unify the wasm backend and the wasm linker to call into
the general purpose `codegen.zig` to generate the code for a function.
This also unifies the wasm backend to use `generateSymbol` when lowering a constant
that cannot be lowered to an immediate value.
As both decls and constants are now refactored, the old `genTypedValue` is removed.
To unify the wasm backend with the other backends, we will now call `generateSymbol` to
lower a Decl into bytes. This means we also have to change some function signatures
to comply with the linker interface.
Since the general purpose generateSymbol is less featureful than wasm's, some tests are
temporarily disabled.
When an union had a zero-sized payload type, we would lower the tag twice. This is fixed
by exiting early when `payload_size` is 0.
With regards to error unions, we were only accounting for padding for the payload field.
However, the errorset value can have a smaller alignment than the payload as well, i.e. error!usize.
We fix this by also accounting for padding/alignment of the error set tag of an error union.
This makes the following work properly (as it does in stage1, too):
var zero_ptr: [*:0]const u8 = undefined;
var no_zero_ptr: [*]const u8 = zero_ptr;
Prior to this this would fail with an "expected type" error since
coercion failed.
This brings back #10950, which was reverted in 5ab5e2e6731a9f1198df6c53134545ccc6a6bbd3
because it [introduced a regression in `zig run`](https://github.com/ziglang/zig/pull/10950#issuecomment-1049481212)
where the runtime arguments passed were incorrect.
I've fixed the issue, and notably this was the only location where we
directly relied on accessing arguments by index in this code still (all
other locations use the iterator proper) and so we should be all good to
go now.
Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
stage1 peer resolves the given test to `[*c]u8` but stage2 makes that a
const u8. I believe stage2 behavior is correct since the pointer itself
is const.
Before this we would see ZIR code like this:
```
%69 = alloc_inferred_mut()
%70 = array_base_ptr(%69)
%71 = elem_ptr_imm(%70, 0)
```
This would crash the compiler because it expects to see a
`coerce_result_ptr` instruction after `alloc_inferred_mut`, but that
does not happen in this case because there is no type to coerce the
result pointer to.
In this commit I modified AstGen so that it has similar codegen as when
using a const instead of a var:
```
%69 = alloc_inferred_mut()
%76 = array_init_anon(.{%71, %73, %75})
%77 = store_to_inferred_ptr(%69, %76)
```
This does not obey result locations, meaning if you call a function
inside the initializer, it will end up doing a copy into the LHS.
Solving this problem, or changing the language to make this legal,
will be left for my future self to deal with. Hi future self!
I see you reading this commit log. Hope you're doing OK buddy.
Sema for `store_ptr` of a tuple where the pointer is in fact the same
element type as the operand had an issue where the comptime fields would
get incorrectly lowered to runtime stores to bogus addresses. This is
solved with an exception to the optimization in Sema for storing
pointers that handles tuples element-wise. In the case that we are
storing a tuple to itself, it skips the optimization. This results in
better code and avoids the problem. However this caused a regression in
GeneralPurposeAllocator from the standard library.
I regressed the test runner code back to the simpler path. It's too
hard to debug standard library code in the LLVM backend right now since
we don't have debug info hooked up. Also, we didn't have any behavior
test coverage of whatever was regressed, so let's try to get that
coverage added as a stepping stone to getting the standard library
working.
The checks detecting such no-op branches (essentially instructions
that branch to the instruction immediately following the branch) were
tightened to catch more of these occurrences.
Now it's centered around a switch on the chosen type tag which gives us
easy access to pointer data.
The logic is simplied and in some cases logic is removed when it is
sufficient to choose the type that is a better coercion target without
knowing whether such coercion will succeed ahead of time.
A bug is fixed at the bottom of the function; we were doing the opposite
of what we were supposed to with `seen_const`.
Also the bottom of the function has a more complete handling of the
possible combinations of `any_are_null`, `convert_to_slice`, and
`err_set_ty`.
In the behavior tests, not as many backends needed to be skipped.
* AIR: use pl_op instead of ty_pl for wasm_memory_size. No need to
store the type because the type is always `u32`.
* AstGen: use coerced_ty for `@wasmMemorySize` and `@wasmMemoryGrow`
and do the coercions in Sema.
* Sema: use more accurate source locations for errors.
* Provide more information in the compiler error message.
* Codegen: use liveness data to avoid lowering unused
`@wasmMemorySize`.
* LLVM backend: add implementation
- I wasn't able to test it because we are hitting a linker error for
`-target wasm32-wasi -fLLVM`.
* C backend: use `zig_unimplemented()` instead of silently doing wrong
behavior for these builtins.
* behavior tests: branch only on stage2_arch for inclusion of the
wasm.zig file. We would change it to `builtin.cpu.arch` but that is
causing a compiler crash on some backends.
This implements the wasm builtins by lowering to builtins that are supported by c-compilers.
In this case: Clang.
This also simplifies the `AIR` instruction as it now uses the payload field of `ty_pl` and `pl_op`
directly to store the index argument rather than storing it inside Extra. This saves us 4 bytes
per builtin call.
Similarly to the other wasm builtin, this implements the grow variation where the memory
index is a comptime known value. The operand as well as the result are runtime values.
This also verifies during semantic analysis the target we're building for is wasm, or else
emits a compilation error. This means that other backends do not have to handle this AIR instruction,
other than the wasm and LLVM backends.
This implements the `wasmMemorySize` builtin, in Sema and the Wasm backend.
The Stage2 implementation differs from stage1 in the way that `index` must be a comptime value.
The stage1 variant is incorrect, as the index is part of the instruction encoding, and therefore,
cannot be a runtime value.
