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Rollup merge of #143388 - bjorn3:lto_refactors, r=compiler-errors

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Various refactors to the LTO handling code

In particular reducing the sharing of code paths between fat and thin-LTO and making the fat LTO implementation more self-contained. This also moves some autodiff handling out of cg_ssa into cg_llvm given that Enzyme only works with LLVM anyway and an implementation for another backend may do things entirely differently. This will also make it a bit easier to split LTO handling out of the coordinator thread main loop into a separate loop, which should reduce the complexity of the coordinator thread.
This commit is contained in:
León Orell Valerian Liehr
2025-07-17 03:58:28 +02:00
committed by GitHub
parent 9ac88eabed 21026cae8d
commit be5f8f299d
13 changed files with 154 additions and 240 deletions
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17
compiler/rustc_codegen_llvm/src/back/lto.rs
View File

@@ -7,7 +7,7 @@ use std::sync::Arc;
use std::{io, iter, slice};
use object::read::archive::ArchiveFile;
use rustc_codegen_ssa::back::lto::{LtoModuleCodegen, SerializedModule, ThinModule, ThinShared};
use rustc_codegen_ssa::back::lto::{SerializedModule, ThinModule, ThinShared};
use rustc_codegen_ssa::back::symbol_export;
use rustc_codegen_ssa::back::write::{CodegenContext, FatLtoInput};
use rustc_codegen_ssa::traits::*;
@@ -201,7 +201,7 @@ pub(crate) fn run_fat(
cgcx: &CodegenContext<LlvmCodegenBackend>,
modules: Vec<FatLtoInput<LlvmCodegenBackend>>,
cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
) -> Result<LtoModuleCodegen<LlvmCodegenBackend>, FatalError> {
) -> Result<ModuleCodegen<ModuleLlvm>, FatalError> {
let dcx = cgcx.create_dcx();
let dcx = dcx.handle();
let (symbols_below_threshold, upstream_modules) = prepare_lto(cgcx, dcx)?;
@@ -217,7 +217,7 @@ pub(crate) fn run_thin(
cgcx: &CodegenContext<LlvmCodegenBackend>,
modules: Vec<(String, ThinBuffer)>,
cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
) -> Result<(Vec<LtoModuleCodegen<LlvmCodegenBackend>>, Vec<WorkProduct>), FatalError> {
) -> Result<(Vec<ThinModule<LlvmCodegenBackend>>, Vec<WorkProduct>), FatalError> {
let dcx = cgcx.create_dcx();
let dcx = dcx.handle();
let (symbols_below_threshold, upstream_modules) = prepare_lto(cgcx, dcx)?;
@@ -248,7 +248,7 @@ fn fat_lto(
cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
mut serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
symbols_below_threshold: &[*const libc::c_char],
) -> Result<LtoModuleCodegen<LlvmCodegenBackend>, FatalError> {
) -> Result<ModuleCodegen<ModuleLlvm>, FatalError> {
let _timer = cgcx.prof.generic_activity("LLVM_fat_lto_build_monolithic_module");
info!("going for a fat lto");
@@ -366,7 +366,7 @@ fn fat_lto(
save_temp_bitcode(cgcx, &module, "lto.after-restriction");
}
Ok(LtoModuleCodegen::Fat(module))
Ok(module)
}
pub(crate) struct Linker<'a>(&'a mut llvm::Linker<'a>);
@@ -436,7 +436,7 @@ fn thin_lto(
serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
cached_modules: Vec<(SerializedModule<ModuleBuffer>, WorkProduct)>,
symbols_below_threshold: &[*const libc::c_char],
) -> Result<(Vec<LtoModuleCodegen<LlvmCodegenBackend>>, Vec<WorkProduct>), FatalError> {
) -> Result<(Vec<ThinModule<LlvmCodegenBackend>>, Vec<WorkProduct>), FatalError> {
let _timer = cgcx.prof.generic_activity("LLVM_thin_lto_global_analysis");
unsafe {
info!("going for that thin, thin LTO");
@@ -568,10 +568,7 @@ fn thin_lto(
}
info!(" - {}: re-compiled", module_name);
opt_jobs.push(LtoModuleCodegen::Thin(ThinModule {
shared: Arc::clone(&shared),
idx: module_index,
}));
opt_jobs.push(ThinModule { shared: Arc::clone(&shared), idx: module_index });
}
// Save the current ThinLTO import information for the next compilation

4
compiler/rustc_codegen_llvm/src/back/write.rs
View File

@@ -817,10 +817,12 @@ pub(crate) fn link(
pub(crate) fn codegen(
cgcx: &CodegenContext<LlvmCodegenBackend>,
dcx: DiagCtxtHandle<'_>,
module: ModuleCodegen<ModuleLlvm>,
config: &ModuleConfig,
) -> Result<CompiledModule, FatalError> {
let dcx = cgcx.create_dcx();
let dcx = dcx.handle();
let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_codegen", &*module.name);
{
let llmod = module.module_llvm.llmod();