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Merge pull request #918 from bjorn3/incr_cache

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Implement incremental caching of object files
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bjorn3 2020-03-11 21:51:11 +01:00 committed by GitHub
commit c2962a603c
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3 changed files with 193 additions and 54 deletions
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2
Readme.md
View File

@ -18,6 +18,7 @@ $ ./test.sh --release
### Cargo
```bash
$ export CG_CLIF_INCR_CACHE=1 # Enable caching of object files in the incremental cache
$ CHANNEL="release" $cg_clif_dir/cargo.sh run
```
@ -26,6 +27,7 @@ If you compiled cg_clif in debug mode you should use `CHANNEL="debug"` instead o
### Rustc
```bash
$ export CG_CLIF_INCR_CACHE=1 # Enable caching of object files in the incremental cache
$ rustc -Cpanic=abort -Zcodegen-backend=$cg_clif_dir/target/release/librustc_codegen_cranelift.so --sysroot $cg_clif_dir/build_sysroot/sysroot my_crate.rs
```

229
src/driver.rs
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@ -2,9 +2,11 @@
use std::ffi::CString;
use std::os::raw::{c_char, c_int};
use rustc::dep_graph::{WorkProduct, WorkProductFileKind, WorkProductId};
use rustc::middle::cstore::EncodedMetadata;
use rustc::mir::mono::{Linkage as RLinkage, Visibility};
use rustc::mir::mono::{CodegenUnit, Linkage as RLinkage, Visibility};
use rustc::session::config::{DebugInfo, OutputType};
use rustc_session::cgu_reuse_tracker::CguReuse;
use rustc_codegen_ssa::back::linker::LinkerInfo;
use rustc_codegen_ssa::CrateInfo;
@ -172,20 +174,32 @@ fn run_aot(
tcx: TyCtxt<'_>,
metadata: EncodedMetadata,
need_metadata_module: bool,
) -> Box<CodegenResults> {
let new_module = |name: String| {
) -> Box<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>)> {
let mut work_products = FxHashMap::default();
fn new_module(tcx: TyCtxt<'_>, name: String) -> Module<crate::backend::Backend> {
let module = crate::backend::make_module(tcx.sess, name);
assert_eq!(pointer_ty(tcx), module.target_config().pointer_type());
module
};
struct ModuleCodegenResult(CompiledModule, Option<(WorkProductId, WorkProduct)>);
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
impl<HCX> HashStable<HCX> for ModuleCodegenResult {
fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) {
// do nothing
}
}
fn emit_module<B: Backend>(
tcx: TyCtxt<'_>,
name: String,
kind: ModuleKind,
mut module: Module<B>,
debug: Option<DebugContext>,
) -> CompiledModule
) -> ModuleCodegenResult
where B::Product: Emit + WriteDebugInfo,
{
module.finalize_definitions();
@ -200,54 +214,146 @@ fn emit_module<B: Backend>(
.temp_path(OutputType::Object, Some(&name));
let obj = product.emit();
std::fs::write(&tmp_file, obj).unwrap();
CompiledModule {
name,
kind,
object: Some(tmp_file),
bytecode: None,
bytecode_compressed: None,
}
};
let (_, cgus) = tcx.collect_and_partition_mono_items(LOCAL_CRATE);
let modules = time(tcx.sess, "codegen mono items", move || {
cgus.iter().map(|cgu| {
let mono_items = cgu.items_in_deterministic_order(tcx);
let mut module = new_module(cgu.name().as_str().to_string());
let mut debug = if tcx.sess.opts.debuginfo != DebugInfo::None {
let debug = DebugContext::new(
tcx,
module.target_config().pointer_type().bytes() as u8,
);
Some(debug)
let work_product = if std::env::var("CG_CLIF_INCR_CACHE").is_ok() {
rustc_incremental::copy_cgu_workproducts_to_incr_comp_cache_dir(
tcx.sess,
&name,
&[(WorkProductFileKind::Object, tmp_file.clone())],
)
} else {
None
};
codegen_mono_items(tcx, &mut module, debug.as_mut(), mono_items);
crate::main_shim::maybe_create_entry_wrapper(tcx, &mut module);
emit_module(
tcx,
cgu.name().as_str().to_string(),
ModuleKind::Regular,
module,
debug,
ModuleCodegenResult(
CompiledModule {
name,
kind,
object: Some(tmp_file),
bytecode: None,
bytecode_compressed: None,
},
work_product,
)
};
let (_, cgus) = tcx.collect_and_partition_mono_items(LOCAL_CRATE);
if tcx.dep_graph.is_fully_enabled() {
for cgu in &*cgus {
tcx.codegen_unit(cgu.name());
}
}
let modules = time(tcx.sess, "codegen mono items", || {
cgus.iter().map(|cgu| {
let cgu_reuse = determine_cgu_reuse(tcx, cgu);
tcx.sess.cgu_reuse_tracker.set_actual_reuse(&cgu.name().as_str(), cgu_reuse);
match cgu_reuse {
CguReuse::No => {}
CguReuse::PreLto => {
let incr_comp_session_dir = tcx.sess.incr_comp_session_dir();
let mut object = None;
let work_product = cgu.work_product(tcx);
for (kind, saved_file) in &work_product.saved_files {
let obj_out = match kind {
WorkProductFileKind::Object => {
let path = tcx.output_filenames(LOCAL_CRATE).temp_path(OutputType::Object, Some(&cgu.name().as_str()));
object = Some(path.clone());
path
}
WorkProductFileKind::Bytecode | WorkProductFileKind::BytecodeCompressed => {
panic!("cg_clif doesn't use bytecode");
}
};
let source_file = rustc_incremental::in_incr_comp_dir(&incr_comp_session_dir, &saved_file);
if let Err(err) = rustc_fs_util::link_or_copy(&source_file, &obj_out) {
tcx.sess.err(&format!(
"unable to copy {} to {}: {}",
source_file.display(),
obj_out.display(),
err
));
}
}
work_products.insert(cgu.work_product_id(), work_product);
return CompiledModule {
name: cgu.name().to_string(),
kind: ModuleKind::Regular,
object,
bytecode: None,
bytecode_compressed: None,
};
}
CguReuse::PostLto => unreachable!(),
}
let dep_node = cgu.codegen_dep_node(tcx);
let (ModuleCodegenResult(module, work_product), _) =
tcx.dep_graph.with_task(dep_node, tcx, cgu.name(), module_codegen, rustc::dep_graph::hash_result);
fn module_codegen(tcx: TyCtxt<'_>, cgu_name: rustc_span::Symbol) -> ModuleCodegenResult {
let cgu = tcx.codegen_unit(cgu_name);
let mono_items = cgu.items_in_deterministic_order(tcx);
let mut module = new_module(tcx, cgu_name.as_str().to_string());
let mut debug = if tcx.sess.opts.debuginfo != DebugInfo::None {
let debug = DebugContext::new(
tcx,
module.target_config().pointer_type().bytes() as u8,
);
Some(debug)
} else {
None
};
codegen_mono_items(tcx, &mut module, debug.as_mut(), mono_items);
crate::main_shim::maybe_create_entry_wrapper(tcx, &mut module);
emit_module(
tcx,
cgu.name().as_str().to_string(),
ModuleKind::Regular,
module,
debug,
)
}
if let Some((id, product)) = work_product {
work_products.insert(id, product);
}
module
}).collect::<Vec<_>>()
});
tcx.sess.abort_if_errors();
let mut allocator_module = new_module("allocator_shim".to_string());
let mut allocator_module = new_module(tcx, "allocator_shim".to_string());
let created_alloc_shim = crate::allocator::codegen(tcx, &mut allocator_module);
let allocator_module = if created_alloc_shim {
let ModuleCodegenResult(module, work_product) = emit_module(
tcx,
"allocator_shim".to_string(),
ModuleKind::Allocator,
allocator_module,
None,
);
if let Some((id, product)) = work_product {
work_products.insert(id, product);
}
Some(module)
} else {
None
};
rustc_incremental::assert_dep_graph(tcx);
rustc_incremental::save_dep_graph(tcx);
rustc_incremental::finalize_session_directory(tcx.sess, tcx.crate_hash(LOCAL_CRATE));
let metadata_module = if need_metadata_module {
let _timer = tcx.prof.generic_activity("codegen crate metadata");
@ -284,27 +390,17 @@ fn emit_module<B: Backend>(
None
};
Box::new(CodegenResults {
Box::new((CodegenResults {
crate_name: tcx.crate_name(LOCAL_CRATE),
modules,
allocator_module: if created_alloc_shim {
Some(emit_module(
tcx,
"allocator_shim".to_string(),
ModuleKind::Allocator,
allocator_module,
None,
))
} else {
None
},
allocator_module,
metadata_module,
crate_hash: tcx.crate_hash(LOCAL_CRATE),
metadata,
windows_subsystem: None, // Windows is not yet supported
linker_info: LinkerInfo::new(tcx),
crate_info: CrateInfo::new(tcx),
})
}, work_products))
}
fn codegen_mono_items<'tcx>(
@ -402,3 +498,36 @@ fn time<R>(sess: &Session, name: &'static str, f: impl FnOnce() -> R) -> R {
println!("[{}] end time: {:?}", name, after - before);
res
}
// Adapted from https://github.com/rust-lang/rust/blob/303d8aff6092709edd4dbd35b1c88e9aa40bf6d8/src/librustc_codegen_ssa/base.rs#L922-L953
fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
if !tcx.dep_graph.is_fully_enabled() {
return CguReuse::No;
}
let work_product_id = &cgu.work_product_id();
if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
// We don't have anything cached for this CGU. This can happen
// if the CGU did not exist in the previous session.
return CguReuse::No;
}
// Try to mark the CGU as green. If it we can do so, it means that nothing
// affecting the LLVM module has changed and we can re-use a cached version.
// If we compile with any kind of LTO, this means we can re-use the bitcode
// of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
// know that later). If we are not doing LTO, there is only one optimized
// version of each module, so we re-use that.
let dep_node = cgu.codegen_dep_node(tcx);
assert!(
!tcx.dep_graph.dep_node_exists(&dep_node),
"CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
cgu.name()
);
if tcx.dep_graph.try_mark_green(tcx, &dep_node).is_some() {
CguReuse::PreLto
} else {
CguReuse::No
}
}

16
src/lib.rs
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@ -21,7 +21,7 @@
use std::any::Any;
use rustc::dep_graph::DepGraph;
use rustc::dep_graph::{DepGraph, WorkProduct, WorkProductId};
use rustc::middle::cstore::{EncodedMetadata, MetadataLoader};
use rustc::session::config::OutputFilenames;
use rustc::ty::query::Providers;
@ -216,10 +216,16 @@ fn codegen_crate<'tcx>(
fn join_codegen(
&self,
ongoing_codegen: Box<dyn Any>,
_sess: &Session,
_dep_graph: &DepGraph,
sess: &Session,
dep_graph: &DepGraph,
) -> Result<Box<dyn Any>, ErrorReported> {
Ok(ongoing_codegen)
let (codegen_results, work_products) = *ongoing_codegen.downcast::<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>)>().unwrap();
sess.time("serialize_work_products", move || {
rustc_incremental::save_work_product_index(sess, &dep_graph, work_products)
});
Ok(Box::new(codegen_results))
}
fn link(
@ -247,6 +253,8 @@ fn link(
);
});
rustc_incremental::finalize_session_directory(sess, codegen_results.crate_hash);
Ok(())
}
}