Note that with this commit, casting through
multiply-nested unions is forbidden, e.g.
```
U :: union {int, V}
V :: union {bool}
x: U = true
```
does not compile.
(Previously the compiler would simply crash)
This is to avoid situations where adding variants
can lead to unexpected changes in the value.
For example if `U` is changed to have a `bool`
variant of its own:
```
U :: union {int, bool, V}
```
Then `x: U = true` would equal
`U(true)` instead of `U(V(true))`.
Single-variant unions are exempt, primarily to
improve the ergonomics of `Maybe` in cases like:
```
x: Maybe(union{int, bool}) = 1
```
Fix#6100Fix#6699Fix#6895Fix#6896Fix#6897Fix#7036Fix#7083Fix#7091
arm32: implement AAPCS32 homogeneous float aggregates incl unions,
arm32: fix reversed arguments in the small-struct return coercion,abi test: __aeabi_uldivmod so the arm32 corpus links
Fixes#6926.
If `build` is a subdirectory in the current directory, then `odin build . -out:build` will place `.S`, `.obj` and `.ll` files there if the corresponding `-build-mode` is given.
With ThinLTO, the linker runs sanitizer passes at link time via
-fsanitize= flags, where it has whole-program visibility. Running
them at bitcode emission too double-instruments every module,
producing hundreds of "Redundant instrumentation detected" warnings.
Per-function sanitize/no_sanitize attributes are preserved in the
bitcode and respected by the linker's pass.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add -lto:thin and -lto:thin-files CLI flags with validation
- Emit LLVM bitcode (.bc) instead of object files when LTO is enabled
- Pass -flto=thin and -flto-jobs to clang/lld linkers
- Guard linkage corrections to skip declarations without definitions
(required for LTO where declarations appear across modules)
- Allow module-per-file with LTO even at higher optimization levels
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
