1b3a5f29dd
Allow loading LLVM plugins with both legacy and new pass manager Opening a draft PR to get feedback and start discussion on this feature. There is already a codegen option `passes` which allow giving a list of LLVM pass names, however we currently can't use a LLVM pass plugin (as described here : https://llvm.org/docs/WritingAnLLVMPass.html), the only available passes are the LLVM built-in ones. The proposed modification would be to add another codegen option `pass-plugins`, which can be set with a list of paths to shared library files. These libraries are loaded using the LLVM function `PassPlugin::Load`, which calls the expected symbol `lvmGetPassPluginInfo`, and register the pipeline parsing and optimization callbacks. An example usage with a single plugin and 3 passes would look like this in the `.cargo/config`: ```toml rustflags = [ "-C", "pass-plugins=/tmp/libLLVMPassPlugin", "-C", "passes=pass1 pass2 pass3", ] ``` This would give the same functionality as the opt LLVM tool directly integrated in rust build system. Additionally, we can also not specify the `passes` option, and use a plugin which inserts passes in the optimization pipeline, as one could do using clang. |
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| Cargo.toml | ||
| 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.