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Auto merge of #52266 - michaelwoerister:incr-thinlto-preliminaries, r=alexcrichton

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Preliminary work for incremental ThinLTO.

Since implementing incremental ThinLTO is a bit more involved than I initially thought, I'm splitting out some of the things that already work. This PR (1) adds a way accessing some ThinLTO information in `rustc` and (2) does some cleanup around CGU/object file naming (which makes things quite a bit nicer).

This is probably best reviewed one commit at a time.
This commit is contained in:
bors 2018-07-13 22:06:38 +00:00
commit a14a361c2c
25 changed files with 457 additions and 171 deletions
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102
src/librustc_codegen_llvm/base.rs
View file

@ -29,7 +29,7 @@ use super::ModuleCodegen;
use super::ModuleKind;
use abi;
use back::link;
use back::{link, lto};
use back::write::{self, OngoingCodegen, create_target_machine};
use llvm::{ContextRef, ModuleRef, ValueRef, Vector, get_param};
use llvm;
@ -739,15 +739,18 @@ pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
let link_meta = link::build_link_meta(crate_hash);
// Codegen the metadata.
let llmod_id = "metadata";
let metadata_cgu_name = CodegenUnit::build_cgu_name(tcx,
LOCAL_CRATE,
&["crate"],
Some("metadata")).as_str()
.to_string();
let (metadata_llcx, metadata_llmod, metadata) =
time(tcx.sess, "write metadata", || {
write_metadata(tcx, llmod_id, &link_meta)
write_metadata(tcx, &metadata_cgu_name, &link_meta)
});
let metadata_module = ModuleCodegen {
name: link::METADATA_MODULE_NAME.to_string(),
llmod_id: llmod_id.to_string(),
name: metadata_cgu_name,
source: ModuleSource::Codegened(ModuleLlvm {
llcx: metadata_llcx,
llmod: metadata_llmod,
@ -810,26 +813,30 @@ pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
// Codegen an allocator shim, if any
let allocator_module = if let Some(kind) = *tcx.sess.allocator_kind.get() {
unsafe {
let llmod_id = "allocator";
let (llcx, llmod) =
context::create_context_and_module(tcx.sess, llmod_id);
let modules = ModuleLlvm {
llmod,
llcx,
tm: create_target_machine(tcx.sess, false),
};
time(tcx.sess, "write allocator module", || {
let llmod_id = CodegenUnit::build_cgu_name(tcx,
LOCAL_CRATE,
&["crate"],
Some("allocator")).as_str()
.to_string();
let (llcx, llmod) = unsafe {
context::create_context_and_module(tcx.sess, &llmod_id)
};
let modules = ModuleLlvm {
llmod,
llcx,
tm: create_target_machine(tcx.sess, false),
};
time(tcx.sess, "write allocator module", || {
unsafe {
allocator::codegen(tcx, &modules, kind)
});
}
});
Some(ModuleCodegen {
name: link::ALLOCATOR_MODULE_NAME.to_string(),
llmod_id: llmod_id.to_string(),
source: ModuleSource::Codegened(modules),
kind: ModuleKind::Allocator,
})
}
Some(ModuleCodegen {
name: llmod_id,
source: ModuleSource::Codegened(modules),
kind: ModuleKind::Allocator,
})
} else {
None
};
@ -872,21 +879,10 @@ pub fn codegen_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
// succeed it means that none of the dependencies has changed
// and we can safely re-use.
if let Some(dep_node_index) = tcx.dep_graph.try_mark_green(tcx, dep_node) {
// Append ".rs" to LLVM module identifier.
//
// LLVM code generator emits a ".file filename" directive
// for ELF backends. Value of the "filename" is set as the
// LLVM module identifier. Due to a LLVM MC bug[1], LLVM
// crashes if the module identifier is same as other symbols
// such as a function name in the module.
// 1. http://llvm.org/bugs/show_bug.cgi?id=11479
let llmod_id = format!("{}.rs", cgu.name());
let module = ModuleCodegen {
name: cgu.name().to_string(),
source: ModuleSource::Preexisting(buf),
kind: ModuleKind::Regular,
llmod_id,
};
tcx.dep_graph.mark_loaded_from_cache(dep_node_index, true);
write::submit_codegened_module_to_llvm(tcx, module, 0);
@ -1195,21 +1191,8 @@ fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
{
let cgu_name = cgu.name().to_string();
// Append ".rs" to LLVM module identifier.
//
// LLVM code generator emits a ".file filename" directive
// for ELF backends. Value of the "filename" is set as the
// LLVM module identifier. Due to a LLVM MC bug[1], LLVM
// crashes if the module identifier is same as other symbols
// such as a function name in the module.
// 1. http://llvm.org/bugs/show_bug.cgi?id=11479
let llmod_id = format!("{}-{}.rs",
cgu.name(),
tcx.crate_disambiguator(LOCAL_CRATE)
.to_fingerprint().to_hex());
// Instantiate monomorphizations without filling out definitions yet...
let cx = CodegenCx::new(tcx, cgu, &llmod_id);
let cx = CodegenCx::new(tcx, cgu);
let module = {
let mono_items = cx.codegen_unit
.items_in_deterministic_order(cx.tcx);
@ -1267,7 +1250,6 @@ fn compile_codegen_unit<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
name: cgu_name,
source: ModuleSource::Codegened(llvm_module),
kind: ModuleKind::Regular,
llmod_id,
}
};
@ -1370,6 +1352,27 @@ mod temp_stable_hash_impls {
}
}
#[allow(unused)]
fn load_thin_lto_imports(sess: &Session) -> lto::ThinLTOImports {
let path = rustc_incremental::in_incr_comp_dir_sess(
sess,
lto::THIN_LTO_IMPORTS_INCR_COMP_FILE_NAME
);
if !path.exists() {
return lto::ThinLTOImports::new();
}
match lto::ThinLTOImports::load_from_file(&path) {
Ok(imports) => imports,
Err(e) => {
let msg = format!("Error while trying to load ThinLTO import data \
for incremental compilation: {}", e);
sess.fatal(&msg)
}
}
}
pub fn define_custom_section(cx: &CodegenCx, def_id: DefId) {
use rustc::mir::interpret::GlobalId;
@ -1408,3 +1411,4 @@ pub fn define_custom_section(cx: &CodegenCx, def_id: DefId) {
);
}
}