rust/compiler/rustc_codegen_llvm
bors 0c72c0d11a Auto merge of #133250 - DianQK:embed-bitcode-pgo, r=nikic
The embedded bitcode should always be prepared for LTO/ThinLTO

Fixes #115344. Fixes #117220.

There are currently two methods for generating bitcode that used for LTO. One method involves using `-C linker-plugin-lto` to emit object files as bitcode, which is the typical setting used by cargo. The other method is through `-C embed-bitcode=yes`.

When using with `-C embed-bitcode=yes -C lto=no`, we run a complete non-LTO LLVM pipeline to obtain bitcode, then the bitcode is used for LTO. We run the Call Graph Profile Pass twice on the same module.

This PR is doing something similar to LLVM's `buildFatLTODefaultPipeline`, obtaining the bitcode for embedding after running `buildThinLTOPreLinkDefaultPipeline`.

r? nikic
2025-03-01 08:22:18 +00:00
..
src Auto merge of #133250 - DianQK:embed-bitcode-pgo, r=nikic 2025-03-01 08:22:18 +00:00
Cargo.toml Upgrade the compiler to edition 2024 2025-02-22 00:01:48 +00:00
messages.ftl update autodiff flags 2025-02-21 21:51:20 -05:00
README.md

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.