rust/compiler/rustc_codegen_llvm
bors a8207df49e Auto merge of #105812 - ojeda:no-jump-tables, r=nikic
Add `-Zno-jump-tables`

This flag mimics GCC/Clang's `-fno-jump-tables` [1][2], which makes the codegen backend avoid generating jump tables when lowering switches.

In the case of LLVM, the `"no-jump-tables"="true"` function attribute is added to every function.

The kernel currently needs it for x86 when enabling IBT [3], as well as for Alpha (plus VDSO objects in MIPS/LoongArch).

[1] https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#index-fno-jump-tables
[2] https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-fjump-tables
[3] https://github.com/torvalds/linux/blob/v6.1/arch/x86/Makefile#L75-L83
2022-12-21 17:38:38 +00:00
..
src Auto merge of #105812 - ojeda:no-jump-tables, r=nikic 2022-12-21 17:38:38 +00:00
Cargo.toml Rewrite LLVM's archive writer in Rust 2022-11-26 19:35:32 +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.