From a17193dbb931ea0c8b66d82f640385bce8b4929a Mon Sep 17 00:00:00 2001 From: Michael Benfield Date: Fri, 7 May 2021 07:41:37 +0000 Subject: Enable AutoFDO. This largely involves implementing the options debug-info-for-profiling and profile-sample-use and forwarding them on to LLVM. AutoFDO can be used on x86-64 Linux like this: rustc -O -Cdebug-info-for-profiling main.rs -o main perf record -b ./main create_llvm_prof --binary=main --out=code.prof rustc -O -Cprofile-sample-use=code.prof main.rs -o main2 Now `main2` will have feedback directed optimization applied to it. The create_llvm_prof tool can be obtained from this github repository: https://github.com/google/autofdo Fixes #64892. --- compiler/rustc_codegen_ssa/src/back/linker.rs | 3 +++ compiler/rustc_codegen_ssa/src/back/write.rs | 4 ++++ 2 files changed, 7 insertions(+) (limited to 'compiler/rustc_codegen_ssa') diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs index e3b0eea0d89..429dc45d6a4 100644 --- a/compiler/rustc_codegen_ssa/src/back/linker.rs +++ b/compiler/rustc_codegen_ssa/src/back/linker.rs @@ -286,6 +286,9 @@ impl<'a> GccLinker<'a> { config::OptLevel::Aggressive => "O3", }; + if let Some(path) = &self.sess.opts.debugging_opts.profile_sample_use { + self.linker_arg(&format!("-plugin-opt=sample-profile={}", path.display())); + }; self.linker_arg(&format!("-plugin-opt={}", opt_level)); self.linker_arg(&format!("-plugin-opt=mcpu={}", self.target_cpu)); } diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs index 31722d07414..da34612ce76 100644 --- a/compiler/rustc_codegen_ssa/src/back/write.rs +++ b/compiler/rustc_codegen_ssa/src/back/write.rs @@ -83,6 +83,8 @@ pub struct ModuleConfig { pub pgo_gen: SwitchWithOptPath, pub pgo_use: Option, + pub pgo_sample_use: Option, + pub debug_info_for_profiling: bool, pub instrument_coverage: bool, pub instrument_gcov: bool, @@ -176,6 +178,8 @@ impl ModuleConfig { SwitchWithOptPath::Disabled ), pgo_use: if_regular!(sess.opts.cg.profile_use.clone(), None), + pgo_sample_use: if_regular!(sess.opts.debugging_opts.profile_sample_use.clone(), None), + debug_info_for_profiling: sess.opts.debugging_opts.debug_info_for_profiling, instrument_coverage: if_regular!(sess.instrument_coverage(), false), instrument_gcov: if_regular!( // compiler_builtins overrides the codegen-units settings, -- cgit 1.4.1-3-g733a5