We use long calls for these just like thumb*-linux-* to prevent range issues as
the binaries grow larger over time.
We also need function and data sections due to the many __stack_chk_guard
references within the std test binary; without these options, the linker is not
able to insert range thunks in between functions because the std binary just has
one giant .text section that's opaque to the linker.
closes https://codeberg.org/ziglang/zig/issues/30923
e2338edb47 didn't *quite* do it, the call sites of all switch prong related
functions now have to do their part too and be a little more precise about
what kind of prong they're currently analyzing.
Also removes some unused/unnecessary stuff.
This fixes a regression from a couple of commits ago; breaking from the
`else` block of a loop to the loop's tag should be allowed when explicitly
targeting the label by name.
This commit aims to simplify and de-duplicate the logic required for
semantically analyzing `switch` expressions.
The core logic has been moved to `analyzeSwitchBlock`, `resolveSwitchBlock`
and `finishSwitchBlock` and has been rewritten around the new iterator-based
API exposed by `Zir.UnwrappedSwitchBlock`.
All validation logic and switch prong item resolution have been moved to
`validateSwitchBlock`, which produces a `ValidatedSwitchBlock` containing
all the necessary information for further analysis.
`Zir.UnwrappedSwitchBlock`, `ValidatedSwitchBlock` and `SwitchOperand`
replace `SwitchProngAnalysis` while adding more flexibility, mainly for
better integration with `switch_block_err_union`.
`analyzeSwitchBlock` has an explicit code path for OPV types which lowers
them to either a `block`-`br` or a `loop`-`repeat` construct instead of a
switch. Backends expect `switch` to actually have an operand that exists
at runtime, so this is a bug fix and avoids further special cases in the
rest of the switch logic.
`resolveSwitchBlock` and `finishSwitchBr` exclusively deal with operands
which can have more than one value, at comptime and at runtime respectively.
This commit also reworks `RangeSet` to be an unmanaged container and adds
`Air.SwitchBr.BranchHints` to offload some complexity from Sema to there
and save a few bytes of memory in the process.
Additionally, some new features have been implemented:
- decl literals and everything else requiring a result type (`@enumFromInt`!)
may now be used as switch prong items
- union tag captures are now allowed for all prongs, not just `inline` ones
- switch prongs may contain errors which are not in the error set being
switched on, if these prongs contain `=> comptime unreachable`
and some bugs have been fixed:
- lots of issues with switching on OPV types are now fixed
- the rules around unreachable `else` prongs when switching on errors now
apply to *any* switch on an error, not just to `switch_block_err_union`,
and are applied properly based on the AST
- switching on `void` no longer requires an `else` prong unconditionally
- lazy values are properly resolved before any comparisons with prong items
- evaluation order between all kinds of switch statements is now the same,
with or without label
Enhances `GenZir` to allow labels to provide separate `break` and `continue`
target blocks and adds some more information on continue targets to
communicate whether the target is a switch block or cannot be targeted by
`continue` at all.
The main motivation is enabling this:
```
const result: u32 = operand catch |err| label: switch (err) {
else => continue :label error.MyError,
error.MyError => break :label 1,
};
```
to be lowered to something like this:
```
%1 = block({
%2 = is_non_err(%operand)
%3 = condbr(%2, {
%4 = err_union_payload_unsafe(%operand)
%5 = break(%1, result) // targets enclosing `block`
}, {
%6 = err_union_code(%operand)
%7 = switch_block(%6,
else => {
%8 = switch_continue(%7, "error.MyError") // targets `switch_block`
},
"error.MyError" => {
%9 = break(%1, @one) // targets enclosing `block`
},
)
%10 = break(%1, @void_value)
})
})
```
which makes the non-error case and all breaks from switch prongs, but not
continues from switch prongs, peers.
This is required to avoid the problems described in gh#11957 for labeled
switches without having to introduce a fairly complex special case to the
`switch_block_err_union` logic. Since this construct is very rare in practice,
introducing this additional complexity just to save a few ZIR bytes is
likely not worth it, so the simplified lowering described above will be
used instead.
As a nice bonus, AstGen can now also detect a `continue` trying to target
a labeled block and emit an appropriate error message.
Previously Zig allowed you to write something like,
```zig
switch (x) {
.y => |_| {
```
This seems a bit strange because in other cases, such as when
capturing the tag in a switch case,
```zig
switch (x) {
.y => |_, _| {
```
this produces an error.
The only usecase I can think of for the previous behaviour is
if you wanted to assert that all union payloads are able
to coerce,
```zig
const X = union(enum) { y: u8, z: f32 };
switch (x) {
.y, .z => |_| {
```
This will compile-error with the `|_|` and pass without it.
I don't believe this usecase is strong enough to keep the current
behaviour; it was never used in the Zig codebase and I cannot
find a single usage of this behaviour in the real world, searching
through Sourcegraph.
If the float can store all possible values of the integer without
rounding, coercion is allowed. The integer's precision must be less than
or equal to the float's significand precision.
Closes#18614
Our implementation did the classic add-sub rounding trick `(y = x +/- C =+ C - x)`
with `C = 1 / eps(T) = 2^(mantissa - 1)`. This approach only works for values whose
magnitude is below the rounding capacity of the constant. For a 64-bit mantissa
(like f80 has), `C = 2^63` only rounds for `|x| < 2^63`. Before we allowed this to
be ran on `e < bias + 64` aka `|x| < 2^64`. And because it isn't large enough,
we lose a bit to rounding.
For reference, the musl implementation does the same thing, using `mantissa - 1`:
https://git.musl-libc.org/cgit/musl/tree/src/math/ceill.c#n18
where `LDBL_MANT_DIG` is 64 for `long double` on x86.
This commit also combines the floor and ceil implementations into one generic one.
Remove the RemoveDir step with no replacement. This step had no valid
purpose. Mutating source files? That should be done with
UpdateSourceFiles step. Deleting temporary directories? That required
creating the tmp directories in the configure phase which is broken.
Deleting cached artifacts? That's going to cause problems.
Similarly, remove the `Build.makeTempPath` function. This was used to
create a temporary path in the configure place which, again, is the
wrong place to do it.
Instead, the WriteFile step has been updated with more functionality:
tmp mode: In this mode, the directory will be placed inside "tmp" rather
than "o", and caching will be skipped. During the `make` phase, the step
will always do all the file system operations, and on successful build
completion, the dir will be deleted along with all other tmp
directories. The directory is therefore eligible to be used for
mutations by other steps. `Build.addTempFiles` is introduced to
initialize a WriteFile step with this mode.
mutate mode: The operations will not be performed against a freshly
created directory, but instead act against a temporary directory.
`Build.addMutateFiles` is introduced to initialize a WriteFile step with
this mode.
`Build.tmpPath` is introduced, which is a shortcut for
`Build.addTempFiles` followed by `WriteFile.getDirectory`.
* give Cache a gpa rather than arena because that's what it asks for
