Tracking Issue for LLVM Control Flow Integrity (CFI) Support for Rust #89653

This is a tracking issue for the LLVM Control Flow Integrity (CFI) Support for Rust project (see the design document).

Steps

LLVM CFI support for Rust work will be implemented in these steps:

• Add option to the Rust compiler driver and frontend. (Add LLVM CFI support to the Rust compiler #89652)
• Add support for emitting type metadata and checks to the Rust compiler code generation. (Add LLVM CFI support to the Rust compiler #89652)
• Implement Rust-compiled code only LLVM CFI support by using Rust-specific type metadata identifiers. (Add LLVM CFI support to the Rust compiler #89652, Add fine-grained LLVM CFI support to the Rust compiler #95548)
• Define type metadata identifiers for cross-language LLVM CFI support. (See the design document.)
• Change initial implementation to use the defined type metadata identifiers for cross-language LLVM CFI support. (Add fine-grained LLVM CFI support to the Rust compiler #95548, RFC: Improve C types for cross-language LLVM CFI support rfcs#3296, Add cross-language LLVM CFI support to the Rust compiler #105452)
• Create documentation and tests. (Add LLVM CFI support to the Rust compiler #89652, Add documentation for LLVM CFI support rustc-dev-guide#1234, Add fine-grained LLVM CFI support to the Rust compiler #95548, Add cross-language LLVM CFI support to the Rust compiler #105452)

Unresolved Questions

• Should integers always be normalized?

Implementation history

1. Add LLVM CFI support to the Rust compiler #89652
2. Add documentation for LLVM CFI support rustc-dev-guide#1234
3. Add fine-grained LLVM CFI support to the Rust compiler #95548
4. RFC: Improve C types for cross-language LLVM CFI support rfcs#3296
5. [LLVM] Add CFI integer types normalization to Clang compiler
6. Add cross-language LLVM CFI support to the Rust compiler #105452

Bonus implementation

1. Add LLVM KCFI support to the Rust compiler #105109
2. Add documentation for LLVM KCFI support rustc-dev-guide#1529

Known issues

https://github.com/rust-lang/rust/issues?q=is:open+label:PG-exploit-mitigations+-label:C-tracking-issue+CFI