as explainded at https://llvm.org/docs/LangRef.html#vector-type :
"In general vector elements are laid out in memory in the same way as array types.
Such an analogy works fine as long as the vector elements are byte sized.
However, when the elements of the vector aren’t byte sized it gets a bit more complicated.
One way to describe the layout is by describing what happens when a vector such
as <N x iM> is bitcasted to an integer type with N*M bits, and then following the
rules for storing such an integer to memory."
"When <N*M> isn’t evenly divisible by the byte size the exact memory layout
is unspecified (just like it is for an integral type of the same size)."
The changes to result locations and generic calls has caused mild
changes to some compile errors. Some are slightly better, some slightly
worse, but none of the changes are major.
AstGen provides all function call arguments with a result location,
referenced through the call instruction index. The idea is that this
should be the parameter type, but for `anytype` parameters, we use
generic poison, which is required to be handled correctly.
Previously, generic instantiations and inline calls worked by evaluating
all args in advance, before resolving generic parameter types. This
means any generic parameter (not just `anytype` ones) had generic poison
result types. This caused missing result locations in some cases.
Additionally, the generic instantiation logic caused `zirParam` to
analyze the argument types a second time before coercion. This meant
that for nominal types (struct/enum/etc), a *new* type was created,
distinct to the result type which was previously forwarded to the
argument expression.
This commit fixes both of these issues. Generic parameter type
resolution is now interleaved with argument analysis, so that we don't
have unnecessary generic poison types, and generic instantiation logic
now handles parameters itself rather than falling through to the
standard zirParam logic, so avoids duplicating the types.
Resolves: #16566Resolves: #16258Resolves: #16753
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.
This function does not seem to differ in any interesting way from
`!typeRequiresComptime`, other than the `is_extern` param which is only
used in one place, and some differences did not seem correct anyway.
My reasoning for changing opaque types to be comptime-only is that
`explainWhyTypeIsComptime` is quite happy to explain why they are. :D
After fixing some issues with inline assembly in the C backend, the std
cleanups have the side effect of making these functions compatible with
the backend, allowing it to be used on linux without linking libc.
* introduce LazyPath.cwd_relative variant and use it for --zig-lib-dir. closes#12685
* move overrideZigLibDir and setMainPkgPath to options fields set once
and then never mutated.
* avoid introducing Build/util.zig
* use doc comments for deprecation notices so that they show up in
generated documentation.
* introduce InstallArtifact.Options, accept it as a parameter to
addInstallArtifact, and move override_dest_dir into it. Instead of
configuring the installation via Compile step, configure the
installation via the InstallArtifact step. In retrospect this is
obvious.
* remove calls to pushInstalledFile in InstallArtifact. See #14943
* rewrite InstallArtifact to not incorrectly observe whether a Compile
step has any generated outputs. InstallArtifact is meant to trigger
output generation.
* fix child process evaluation code handling of `-fno-emit-bin`.
* don't store out_h_filename, out_ll_filename, etc., pointlessly. these
are all just simple extensions appended to the root name.
* make emit_directory optional. It's possible to have nothing outputted,
for example, if you're just type-checking.
* avoid passing -femit-foo/-fno-emit-foo when it is the default
* rename ConfigHeader.getTemplate to getOutput
* deprecate addOptionArtifact
* update the random number seed of Options step caching.
* avoid using `inline for` pointlessly
* avoid using `override_Dest_dir` pointlessly
* avoid emitting an executable pointlessly in test cases
Removes forceBuild and forceEmit. Let's consider these additions separately.
Nearly all of the usage sites were suspicious.
This change allows the following types to appear in extern structs:
* Zero-bit integers
* void
* zero-sized structs and packed structs
* enums with zero-bit backing integers
* arrays of any length with zero-size elements
When acessing a packed struct member via a byte aligned ptr (from the optimisation in Sema.structFieldPtrByIndex())
the codegen must apply the parent ptr packed_offset in addition to the field offset itself.
resolves https://github.com/ziglang/zig/issues/16609
This commit does two things which seem unrelated at first, but,
together, solve a miscompilation, and potentially slightly speed up
compiler perf, at the expense of making #2765 trickier to implement in
the future.
Sema: avoid returning a false positive for whether an inferred error set
is comptime-known to be empty.
AstGen: mark function calls as not being interested in a result
location. This prevents the test case "ret_ptr doesn't cause own
inferred error set to be resolved" from being regressed. If we want to
accept and implement #2765 in the future, it will require solving this
problem a different way, but the principle of YAGNI tells us to go ahead
with this change.
Old ZIR looks like this:
%97 = ret_ptr()
%101 = store_node(%97, %100)
%102 = load(%97)
%103 = ret_is_non_err(%102)
New ZIR looks like this:
%97 = ret_type()
%101 = as_node(%97, %100)
%102 = ret_is_non_err(%101)
closes#15669
