We currently have `isRef` return true for any type of union, including
packed unions. This means we can simply load it from the data section
to the exact type we want. In the future we can optimize it so it works
similarly to packed structs below 64 bits which do not get stored in
the data section and are not passed by ref.
Previously we would only store the payload, but not the actual tag
that was set. This meant miscompilations where it would incorrectly
return the tag value.
This also adds a tiny optimization for payloads which are not `byRef`
by directly storing them based on offset, rather than first calculating
a pointer to an offset.
Previously it was incorrectly assumed that all memcopy's generated by
the `memcpy` AIR instruction had an element size of 1 byte. However,
this would result in miscompilations for pointer's to arrays where
the element size of the array was larger than 1 byte. We now corectly
calculate this size.
`-l :path/to/lib.so` behavior on gcc/clang is:
- the path is recorded as-is: no paths, exact filename (`libX.so.Y`).
- no rpaths.
The previous version removed the `:` and pretended it's a positional
argument to the linker. That works in almost all cases, except in how
rules_go[1] does things (the Bazel wrapper for Go).
Test case in #15743, output:
gcc rpath:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
0x000000000000001d (RUNPATH) Library runpath: [$ORIGIN/x]
gcc plain:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
zig cc rpath:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
0x000000000000001d (RUNPATH) Library runpath: [$ORIGIN/x]
zig cc plain:
0x0000000000000001 (NEEDED) Shared library: [libversioned.so.2]
Fixes#15743
[1]: https://github.com/bazelbuild/rules_go
The idea here is that there are two ways we can reference a function at runtime:
* Through a direct call, i.e. where the function is comptime-known
* Through a function pointer
This means we can easily perform a form of rudimentary escape analysis
on functions. If we ever see a `decl_ref` or `ref` of a function, we
have a function pointer, which could "leak" into runtime code, so we
emit the function; but for a plain `decl_val`, there's no need to.
This change means that `comptime { _ = f; }` no longer forces a function
to be emitted, which was used for some things (mainly tests). These use
sites have been replaced with `_ = &f;`, which still triggers analysis
of the function body, since you're taking a pointer to the function.
Resolves: #6256Resolves: #15353
* move `ptrBitWidth` from Arch to Target since it needs to know about the abi
* double isn't always 8 bits
* AVR uses 1-byte alignment for everything in GCC
Also get rid of the TTY wrapper struct, which was exlusively used as a
namespace - this is done by the tty.zig root struct now.
detectTTYConfig has been renamed to just detectConfig, which is enough
given the new namespace. Additionally, a doc comment had been added.
Also remove all the wasi-libc files we used to ship, but never compile.
The latest wasi-libc HEAD has an extra commit (a6f871343313220b76009827ed0153586361c0d5), which makes preopen initialization lazy.
Unfortunately, that breaks quite a lot of things on our end. Applications now need to explicitly call __wasilibc_populate_preopens() everywhere when the libc is linked. That can wait after 0.11.
This commit removes the `field_call_bind` and `field_call_bind_named` ZIR
instructions, replacing them with a `field_call` instruction which does the bind
and call in one.
`field_call_bind` is an unfortunate instruction. It's tied into one very
specific usage pattern - its result can only be used as a callee. This means
that it creates a value of a "pseudo-type" of sorts, `bound_fn` - this type used
to exist in Zig, but now we just hide it from the user and have AstGen ensure
it's only used in one way. This is quite silly - `Type` and `Value` should, as
much as possible, reflect real Zig types and values.
It makes sense to instead encode the `a.b()` syntax as its own ZIR instruction,
so that's what we do here. This commit introduces a new instruction,
`field_call`. It's like `call`, but rather than a callee ref, it contains a ref
to the object pointer (`&a` in `a.b()`) and the string field name (`b`). This
eliminates `bound_fn` from the language, and slightly decreases the size of
generated ZIR - stats below.
This commit does remove a few usages which used to be allowed:
- `@field(a, "b")()`
- `@call(.auto, a.b, .{})`
- `@call(.auto, @field(a, "b"), .{})`
These forms used to work just like `a.b()`, but are no longer allowed. I believe
this is the correct choice for a few reasons:
- `a.b()` is a purely *syntactic* form; for instance, `(a.b)()` is not valid.
This means it is *not* inconsistent to not allow it in these cases; the
special case here isn't "a field access as a callee", but rather this exact
syntactic form.
- The second argument to `@call` looks much more visually distinct from the
callee in standard call syntax. To me, this makes it seem strange for that
argument to not work like a normal expression in this context.
- A more practical argument: it's confusing! `@field` and `@call` are used in
very different contexts to standard function calls: the former normally hints
at some comptime machinery, and the latter that you want more precise control
over parts of a function call. In these contexts, you don't want implicit
arguments adding extra confusion: you want to be very explicit about what
you're doing.
Lastly, some stats. I mentioned before that this change slightly reduces the
size of ZIR - this is due to two instructions (`field_call_bind` then `call`)
being replaced with one (`field_call`). Here are some numbers:
+--------------+----------+----------+--------+
| File | Before | After | Change |
+--------------+----------+----------+--------+
| Sema.zig | 4.72M | 4.53M | -4% |
| AstGen.zig | 1.52M | 1.48M | -3% |
| hash_map.zig | 283.9K | 276.2K | -3% |
| math.zig | 312.6K | 305.3K | -2% |
+--------------+----------+----------+--------+
This is in preparation of removing indirect lowering again. Also
modifies constant() to accept a repr so that both direct as well
as indirect representations can be generated. Indirect is not yet
used, but will be used for globals.
Previously the tag type was generated even if it was nonexistant,
triggering an assertion that an integer type should never have
zero bits. Now its only generated when the tag type is actually emitted.
The first dereference of PtrAccessChain returns a pointer of the same type
as the base pointer, in contrast to AccessChain, where the first dereference
returns a pointer of the dereferenced type of the base pointer.
This instruction is not really working well in the LLVM SPIRV translator,
as it is not implemented.
This commit also intruces the constructStruct helper function to initialize
structs at runtime. This is ALSO buggy in the translator, and we must work
around OpCompositeConstruct not working when some of the constituents are
runtime-known only.
Some other improvements are made:
- improved variable() so that it is more useful and no longer requires the
address space. It always puts values in the Function address space,
and returns a pointer to the Generic address space
- adds a boolToInt utility function
This ensures that we can also cast enums and error sets here. In the future
this function will need to be changed to support composite and strange
integers, but that is fine.
It turns out that the Khronos LLVM SPIRV translator does not support OpPtrEqual.
Therefore, this instruction is emitted using a series of conversions.
This commit breaks intToEnum, because enum was removed from the arithmetic type
info. The enum should be converted to an int before this function is called.
When initializing a packed struct, we must ensure the result local
is zero'd. Previously we would do this by ensuring a new local is
allocated. Although a local is always zero by default, it meant that
if such an initialization was being done inside a loop, it would re-
use that very same local that could potentially still hold a different
value. Because this value is `or`'d with the value, it would result
in a miscompilation. By manually setting this result to 0, we guarantee
the correct behavior.
Previously we incorrectly assumed all memset's to have its element
abi-size be 1 byte. This would set the region of memory incorrectly.
We now have a more efficient loop, as well as support any element
type by re-using the `store` function for each element and moving
the pointer by 1 element.
Previously we would use the address of the slice itself, which would
result in miscompilations and accidently setting the memory region
of the slice itself, rather than based on the `ptr` field.
