rust/src/driver/aot.rs

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use std::path::PathBuf;
use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
use rustc_middle::middle::cstore::EncodedMetadata;
use rustc_middle::mir::mono::CodegenUnit;
use rustc_session::config::{DebugInfo, OutputType};
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use rustc_session::cgu_reuse_tracker::CguReuse;
use rustc_codegen_ssa::back::linker::LinkerInfo;
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use rustc_codegen_ssa::{CrateInfo, CodegenResults, CompiledModule, ModuleKind};
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use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
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use crate::prelude::*;
use crate::backend::{Emit, WriteDebugInfo};
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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)>);
impl<HCX> HashStable<HCX> for ModuleCodegenResult {
fn hash_stable(&self, _: &mut HCX, _: &mut StableHasher) {
// do nothing
}
}
fn emit_module<B: Backend>(
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tcx: TyCtxt<'_>,
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name: String,
kind: ModuleKind,
mut module: Module<B>,
debug: Option<DebugContext<'_>>,
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unwind_context: UnwindContext<'_>,
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) -> ModuleCodegenResult
where B::Product: Emit + WriteDebugInfo,
{
module.finalize_definitions();
let mut product = module.finish();
if let Some(mut debug) = debug {
debug.emit(&mut product);
}
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unwind_context.emit(&mut product);
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let tmp_file = tcx
.output_filenames(LOCAL_CRATE)
.temp_path(OutputType::Object, Some(&name));
let obj = product.emit();
std::fs::write(&tmp_file, obj).unwrap();
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let work_product = if std::env::var("CG_CLIF_INCR_CACHE_DISABLED").is_ok() {
None
} else {
rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
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tcx.sess,
&name,
&Some(tmp_file.clone()),
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)
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};
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ModuleCodegenResult(
CompiledModule {
name,
kind,
object: Some(tmp_file),
bytecode: None,
},
work_product,
)
}
fn reuse_workproduct_for_cgu(
tcx: TyCtxt<'_>,
cgu: &CodegenUnit<'_>,
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work_products: &mut FxHashMap<WorkProductId, WorkProduct>,
) -> CompiledModule {
let incr_comp_session_dir = tcx.sess.incr_comp_session_dir();
let mut object = None;
let work_product = cgu.work_product(tcx);
if let Some(saved_file) = &work_product.saved_file {
let obj_out = tcx.output_filenames(LOCAL_CRATE).temp_path(OutputType::Object, Some(&cgu.name().as_str()));
object = Some(obj_out.clone());
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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
));
}
}
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work_products.insert(cgu.work_product_id(), work_product);
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CompiledModule {
name: cgu.name().to_string(),
kind: ModuleKind::Regular,
object,
bytecode: None,
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}
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}
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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);
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let module = new_module(tcx, cgu_name.as_str().to_string());
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let mut global_asm = Vec::new();
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let mut cx = crate::CodegenCx::new(tcx, module, tcx.sess.opts.debuginfo != DebugInfo::None);
super::codegen_mono_items(&mut cx, &mut global_asm, mono_items);
let (mut module, debug, mut unwind_context) = tcx.sess.time("finalize CodegenCx", || cx.finalize());
crate::main_shim::maybe_create_entry_wrapper(tcx, &mut module, &mut unwind_context);
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let global_asm = global_asm.into_iter().map(|hir_id| {
let item = tcx.hir().expect_item(hir_id);
if let rustc_hir::ItemKind::GlobalAsm(rustc_hir::GlobalAsm { asm }) = item.kind {
asm.as_str().to_string()
} else {
bug!("Expected GlobalAsm found {:?}", item);
}
}).collect::<Vec<String>>().join("\n");
let codegen_result = emit_module(
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tcx,
cgu.name().as_str().to_string(),
ModuleKind::Regular,
module,
debug,
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unwind_context,
);
codegen_global_asm(tcx, &cgu.name().as_str(), &global_asm);
codegen_result
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}
pub(super) fn run_aot(
tcx: TyCtxt<'_>,
metadata: EncodedMetadata,
need_metadata_module: bool,
) -> Box<(CodegenResults, FxHashMap<WorkProductId, WorkProduct>)> {
let mut work_products = FxHashMap::default();
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let cgus = if tcx.sess.opts.output_types.should_codegen() {
tcx.collect_and_partition_mono_items(LOCAL_CRATE).1
} else {
// If only `--emit metadata` is used, we shouldn't perform any codegen.
// Also `tcx.collect_and_partition_mono_items` may panic in that case.
&[]
};
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if tcx.dep_graph.is_fully_enabled() {
for cgu in &*cgus {
tcx.ensure().codegen_unit(cgu.name());
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}
}
let modules = super::time(tcx, "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 {
_ if std::env::var("CG_CLIF_INCR_CACHE_DISABLED").is_ok() => {}
CguReuse::No => {}
CguReuse::PreLto => {
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return reuse_workproduct_for_cgu(tcx, &*cgu, &mut work_products);
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}
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_middle::dep_graph::hash_result);
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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(tcx, "allocator_shim".to_string());
let mut allocator_unwind_context = UnwindContext::new(tcx, allocator_module.isa());
let created_alloc_shim = crate::allocator::codegen(
tcx,
&mut allocator_module,
&mut allocator_unwind_context,
);
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let allocator_module = if created_alloc_shim {
let ModuleCodegenResult(module, work_product) = emit_module(
tcx,
"allocator_shim".to_string(),
ModuleKind::Allocator,
allocator_module,
None,
allocator_unwind_context,
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);
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);
let metadata_module = if need_metadata_module {
let _timer = tcx.prof.generic_activity("codegen crate metadata");
let (metadata_cgu_name, tmp_file) = tcx.sess.time("write compressed metadata", || {
use rustc_middle::mir::mono::CodegenUnitNameBuilder;
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let cgu_name_builder = &mut CodegenUnitNameBuilder::new(tcx);
let metadata_cgu_name = cgu_name_builder
.build_cgu_name(LOCAL_CRATE, &["crate"], Some("metadata"))
.as_str()
.to_string();
let tmp_file = tcx
.output_filenames(LOCAL_CRATE)
.temp_path(OutputType::Metadata, Some(&metadata_cgu_name));
let obj = crate::backend::with_object(tcx.sess, &metadata_cgu_name, |object| {
crate::metadata::write_metadata(tcx, object);
});
std::fs::write(&tmp_file, obj).unwrap();
(metadata_cgu_name, tmp_file)
});
Some(CompiledModule {
name: metadata_cgu_name,
kind: ModuleKind::Metadata,
object: Some(tmp_file),
bytecode: None,
})
} else {
None
};
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if tcx.sess.opts.output_types.should_codegen() {
rustc_incremental::assert_module_sources::assert_module_sources(tcx);
}
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Box::new((CodegenResults {
crate_name: tcx.crate_name(LOCAL_CRATE),
modules,
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_global_asm(tcx: TyCtxt<'_>, cgu_name: &str, global_asm: &str) {
use std::io::Write;
use std::process::{Command, Stdio};
if global_asm.is_empty() {
return;
}
let assembler = crate::toolchain::get_toolchain_binary(tcx.sess, "as");
let linker = crate::toolchain::get_toolchain_binary(tcx.sess, "ld");
// Remove all LLVM style comments
let global_asm = global_asm.lines().map(|line| {
if let Some(index) = line.find("//") {
&line[0..index]
} else {
line
}
}).collect::<Vec<_>>().join("\n");
let output_object_file = tcx
.output_filenames(LOCAL_CRATE)
.temp_path(OutputType::Object, Some(cgu_name));
// Assemble `global_asm`
let global_asm_object_file = add_file_stem_postfix(output_object_file.clone(), ".asm");
let mut child = Command::new(assembler)
.arg("-o").arg(&global_asm_object_file)
.stdin(Stdio::piped())
.spawn()
.expect("Failed to spawn `as`.");
child.stdin.take().unwrap().write_all(global_asm.as_bytes()).unwrap();
let status = child.wait().expect("Failed to wait for `as`.");
if !status.success() {
tcx.sess.fatal(&format!("Failed to assemble `{}`", global_asm));
}
// Link the global asm and main object file together
let main_object_file = add_file_stem_postfix(output_object_file.clone(), ".main");
std::fs::rename(&output_object_file, &main_object_file).unwrap();
let status = Command::new(linker)
.arg("-r") // Create a new object file
.arg("-o").arg(output_object_file)
.arg(&main_object_file)
.arg(&global_asm_object_file)
.status()
.unwrap();
if !status.success() {
tcx.sess.fatal(&format!(
"Failed to link `{}` and `{}` together",
main_object_file.display(),
global_asm_object_file.display(),
));
}
std::fs::remove_file(global_asm_object_file).unwrap();
std::fs::remove_file(main_object_file).unwrap();
}
fn add_file_stem_postfix(mut path: PathBuf, postfix: &str) -> PathBuf {
let mut new_filename = path.file_stem().unwrap().to_owned();
new_filename.push(postfix);
if let Some(extension) = path.extension() {
new_filename.push(".");
new_filename.push(extension);
}
path.set_file_name(new_filename);
path
}
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// 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
}
}