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rust/compiler/rustc_codegen_llvm
Nilstrieb 645c0fddd2 Put noundef on all scalars that don't allow uninit
Previously, it was only put on scalars with range validity invariants
like bool, was uninit was obviously invalid for those.

Since then, we have normatively declared all uninit primitives to be
undefined behavior and can therefore put `noundef` on them.

The remaining concern was the `mem::uninitialized` function, which cause
quite a lot of UB in the older parts of the ecosystem. This function now
doesn't return uninit values anymore, making users of it safe from this
change.

The only real sources of UB where people could encounter uninit
primitives are `MaybeUninit::uninit().assume_init()`, which has always
be clear in the docs about being UB and from heap allocations (like
reading from the spare capacity of a vec. This is hopefully rare enough
to not break anything.
2023-01-17 08:14:35 +01:00
..
src Put noundef on all scalars that don't allow uninit 2023-01-17 08:14:35 +01:00
Cargo.toml Fix aarch64-unknown-linux-gnu_ilp32 target 2023-01-09 17:49:24 +00:00
README.md mv compiler to compiler/ 2020-08-30 18:45:07 +03:00

The codegen crate contains the code to convert from MIR into LLVM IR, and then from LLVM IR into machine code. In general it contains code that runs towards the end of the compilation process.

For more information about how codegen works, see the rustc dev guide.