From cae7c76d509386ea29a90c4001bb8dbc59c79d22 Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Sun, 28 Jul 2024 16:54:14 -0400
Subject: [PATCH 1/2] Avoid no-op unlink+link dances in incr comp
---
.../rustc_codegen_cranelift/src/driver/aot.rs | 8 ++++-
compiler/rustc_codegen_ssa/src/back/write.rs | 21 ++++++++----
compiler/rustc_codegen_ssa/src/base.rs | 1 +
compiler/rustc_codegen_ssa/src/lib.rs | 2 ++
compiler/rustc_fs_util/src/lib.rs | 32 +++++++++++--------
.../src/persist/work_product.rs | 7 +++-
6 files changed, 50 insertions(+), 21 deletions(-)
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
index a52b18573b152..d1843f90a07d0 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/aot.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -103,12 +103,14 @@ impl OngoingCodegen {
("o", &module_regular.object.as_ref().unwrap()),
("asm.o", &module_global_asm.object.as_ref().unwrap()),
],
+ &[],
)
} else {
rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
sess,
&module_regular.name,
&[("o", &module_regular.object.as_ref().unwrap())],
+ &[],
)
};
if let Some((work_product_id, work_product)) = work_product {
@@ -381,6 +383,7 @@ fn emit_cgu(
bytecode: None,
assembly: None,
llvm_ir: None,
+ links_from_incr_cache: Vec::new(),
}),
existing_work_product: None,
})
@@ -437,6 +440,7 @@ fn emit_module(
bytecode: None,
assembly: None,
llvm_ir: None,
+ links_from_incr_cache: Vec::new(),
})
}
@@ -487,6 +491,7 @@ fn reuse_workproduct_for_cgu(
bytecode: None,
assembly: None,
llvm_ir: None,
+ links_from_incr_cache: Vec::new(),
},
module_global_asm: has_global_asm.then(|| CompiledModule {
name: cgu.name().to_string(),
@@ -496,6 +501,7 @@ fn reuse_workproduct_for_cgu(
bytecode: None,
assembly: None,
llvm_ir: None,
+ links_from_incr_cache: Vec::new(),
}),
existing_work_product: Some((cgu.work_product_id(), work_product)),
})
@@ -637,6 +643,7 @@ fn emit_metadata_module(tcx: TyCtxt<'_>, metadata: &EncodedMetadata) -> Compiled
bytecode: None,
assembly: None,
llvm_ir: None,
+ links_from_incr_cache: Vec::new(),
}
}
@@ -745,7 +752,6 @@ pub(crate) fn run_aot(
let metadata_module =
if need_metadata_module { Some(emit_metadata_module(tcx, &metadata)) } else { None };
-
Box::new(OngoingCodegen {
modules,
allocator_module,
diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs
index f008bd12ed8fe..b8dc6f93349bf 100644
--- a/compiler/rustc_codegen_ssa/src/back/write.rs
+++ b/compiler/rustc_codegen_ssa/src/back/write.rs
@@ -540,9 +540,12 @@ fn copy_all_cgu_workproducts_to_incr_comp_cache_dir(
if let Some(path) = &module.bytecode {
files.push((OutputType::Bitcode.extension(), path.as_path()));
}
- if let Some((id, product)) =
- copy_cgu_workproduct_to_incr_comp_cache_dir(sess, &module.name, files.as_slice())
- {
+ if let Some((id, product)) = copy_cgu_workproduct_to_incr_comp_cache_dir(
+ sess,
+ &module.name,
+ files.as_slice(),
+ &module.links_from_incr_cache,
+ ) {
work_products.insert(id, product);
}
}
@@ -934,7 +937,9 @@ fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
) -> WorkItemResult<B> {
let incr_comp_session_dir = cgcx.incr_comp_session_dir.as_ref().unwrap();
- let load_from_incr_comp_dir = |output_path: PathBuf, saved_path: &str| {
+ let mut links_from_incr_cache = Vec::new();
+
+ let mut load_from_incr_comp_dir = |output_path: PathBuf, saved_path: &str| {
let source_file = in_incr_comp_dir(incr_comp_session_dir, saved_path);
debug!(
"copying preexisting module `{}` from {:?} to {}",
@@ -943,7 +948,10 @@ fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
output_path.display()
);
match link_or_copy(&source_file, &output_path) {
- Ok(_) => Some(output_path),
+ Ok(_) => {
+ links_from_incr_cache.push(source_file);
+ Some(output_path)
+ }
Err(error) => {
cgcx.create_dcx().handle().emit_err(errors::CopyPathBuf {
source_file,
@@ -966,7 +974,7 @@ fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
load_from_incr_comp_dir(dwarf_obj_out, saved_dwarf_object_file)
});
- let load_from_incr_cache = |perform, output_type: OutputType| {
+ let mut load_from_incr_cache = |perform, output_type: OutputType| {
if perform {
let saved_file = module.source.saved_files.get(output_type.extension())?;
let output_path = cgcx.output_filenames.temp_path(output_type, Some(&module.name));
@@ -986,6 +994,7 @@ fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
}
WorkItemResult::Finished(CompiledModule {
+ links_from_incr_cache,
name: module.name,
kind: ModuleKind::Regular,
object,
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 40238f4b4915a..e4db2bed9e8d9 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -656,6 +656,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
bytecode: None,
assembly: None,
llvm_ir: None,
+ links_from_incr_cache: Vec::new(),
}
})
});
diff --git a/compiler/rustc_codegen_ssa/src/lib.rs b/compiler/rustc_codegen_ssa/src/lib.rs
index 9d2ac219d592c..7ff97f127e033 100644
--- a/compiler/rustc_codegen_ssa/src/lib.rs
+++ b/compiler/rustc_codegen_ssa/src/lib.rs
@@ -102,6 +102,7 @@ impl<M> ModuleCodegen<M> {
bytecode,
assembly,
llvm_ir,
+ links_from_incr_cache: Vec::new(),
}
}
}
@@ -115,6 +116,7 @@ pub struct CompiledModule {
pub bytecode: Option<PathBuf>,
pub assembly: Option<PathBuf>, // --emit=asm
pub llvm_ir: Option<PathBuf>, // --emit=llvm-ir, llvm-bc is in bytecode
+ pub links_from_incr_cache: Vec<PathBuf>,
}
impl CompiledModule {
diff --git a/compiler/rustc_fs_util/src/lib.rs b/compiler/rustc_fs_util/src/lib.rs
index 4e9d21c900df6..0df1b243d697e 100644
--- a/compiler/rustc_fs_util/src/lib.rs
+++ b/compiler/rustc_fs_util/src/lib.rs
@@ -55,25 +55,31 @@ pub enum LinkOrCopy {
Copy,
}
-/// Copies `p` into `q`, preferring to use hard-linking if possible. If
-/// `q` already exists, it is removed first.
+/// Copies `p` into `q`, preferring to use hard-linking if possible.
/// The result indicates which of the two operations has been performed.
pub fn link_or_copy<P: AsRef<Path>, Q: AsRef<Path>>(p: P, q: Q) -> io::Result<LinkOrCopy> {
+ // Creating a hard-link will fail if the destination path already exists. We could defensively
+ // call remove_file in this function, but that pessimizes callers who can avoid such calls.
+ // Incremental compilation calls this function a lot, and is able to avoid calls that
+ // would fail the first hard_link attempt.
+
let p = p.as_ref();
let q = q.as_ref();
- match fs::remove_file(q) {
- Ok(()) => (),
- Err(err) if err.kind() == io::ErrorKind::NotFound => (),
- Err(err) => return Err(err),
- }
- match fs::hard_link(p, q) {
- Ok(()) => Ok(LinkOrCopy::Link),
- Err(_) => match fs::copy(p, q) {
- Ok(_) => Ok(LinkOrCopy::Copy),
- Err(e) => Err(e),
- },
+ let err = match fs::hard_link(p, q) {
+ Ok(()) => return Ok(LinkOrCopy::Link),
+ Err(err) => err,
+ };
+
+ if err.kind() == io::ErrorKind::AlreadyExists {
+ fs::remove_file(q)?;
+ if fs::hard_link(p, q).is_ok() {
+ return Ok(LinkOrCopy::Link);
+ }
}
+
+ // Hard linking failed, fall back to copying.
+ fs::copy(p, q).map(|_| LinkOrCopy::Copy)
}
#[cfg(any(unix, all(target_os = "wasi", target_env = "p1")))]
diff --git a/compiler/rustc_incremental/src/persist/work_product.rs b/compiler/rustc_incremental/src/persist/work_product.rs
index 048981f0d5ce3..7b1eb0a82e397 100644
--- a/compiler/rustc_incremental/src/persist/work_product.rs
+++ b/compiler/rustc_incremental/src/persist/work_product.rs
@@ -3,7 +3,7 @@
//! [work products]: WorkProduct
use std::fs as std_fs;
-use std::path::Path;
+use std::path::{Path, PathBuf};
use rustc_data_structures::unord::UnordMap;
use rustc_fs_util::link_or_copy;
@@ -20,6 +20,7 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
sess: &Session,
cgu_name: &str,
files: &[(&'static str, &Path)],
+ known_links: &[PathBuf],
) -> Option<(WorkProductId, WorkProduct)> {
debug!(?cgu_name, ?files);
sess.opts.incremental.as_ref()?;
@@ -28,6 +29,10 @@ pub fn copy_cgu_workproduct_to_incr_comp_cache_dir(
for (ext, path) in files {
let file_name = format!("{cgu_name}.{ext}");
let path_in_incr_dir = in_incr_comp_dir_sess(sess, &file_name);
+ if known_links.contains(&path_in_incr_dir) {
+ let _ = saved_files.insert(ext.to_string(), file_name);
+ continue;
+ }
match link_or_copy(path, &path_in_incr_dir) {
Ok(_) => {
let _ = saved_files.insert(ext.to_string(), file_name);
From e21502cf9ed247bbf879132b8c62e423d959bd38 Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Tue, 25 Feb 2025 18:41:49 -0500
Subject: [PATCH 2/2] Fill out links_from_incr_cache in cg_clif
---
.../rustc_codegen_cranelift/src/driver/aot.rs | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/compiler/rustc_codegen_cranelift/src/driver/aot.rs b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
index d1843f90a07d0..fb7864ae6124b 100644
--- a/compiler/rustc_codegen_cranelift/src/driver/aot.rs
+++ b/compiler/rustc_codegen_cranelift/src/driver/aot.rs
@@ -464,22 +464,23 @@ fn reuse_workproduct_for_cgu(
err
));
}
+
let obj_out_global_asm =
crate::global_asm::add_file_stem_postfix(obj_out_regular.clone(), ".asm");
- let has_global_asm = if let Some(asm_o) = work_product.saved_files.get("asm.o") {
+ let source_file_global_asm = if let Some(asm_o) = work_product.saved_files.get("asm.o") {
let source_file_global_asm = rustc_incremental::in_incr_comp_dir_sess(&tcx.sess, asm_o);
if let Err(err) = rustc_fs_util::link_or_copy(&source_file_global_asm, &obj_out_global_asm)
{
return Err(format!(
"unable to copy {} to {}: {}",
- source_file_regular.display(),
- obj_out_regular.display(),
+ source_file_global_asm.display(),
+ obj_out_global_asm.display(),
err
));
}
- true
+ Some(source_file_global_asm)
} else {
- false
+ None
};
Ok(ModuleCodegenResult {
@@ -491,9 +492,9 @@ fn reuse_workproduct_for_cgu(
bytecode: None,
assembly: None,
llvm_ir: None,
- links_from_incr_cache: Vec::new(),
+ links_from_incr_cache: vec![source_file_regular],
},
- module_global_asm: has_global_asm.then(|| CompiledModule {
+ module_global_asm: source_file_global_asm.map(|source_file| CompiledModule {
name: cgu.name().to_string(),
kind: ModuleKind::Regular,
object: Some(obj_out_global_asm),
@@ -501,7 +502,7 @@ fn reuse_workproduct_for_cgu(
bytecode: None,
assembly: None,
llvm_ir: None,
- links_from_incr_cache: Vec::new(),
+ links_from_incr_cache: vec![source_file],
}),
existing_work_product: Some((cgu.work_product_id(), work_product)),
})
@@ -752,6 +753,7 @@ pub(crate) fn run_aot(
let metadata_module =
if need_metadata_module { Some(emit_metadata_module(tcx, &metadata)) } else { None };
+
Box::new(OngoingCodegen {
modules,
allocator_module,