1992 lines
82 KiB
Rust
1992 lines
82 KiB
Rust
use super::link::{self, ensure_removed};
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use super::linker::LinkerInfo;
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use super::lto::{self, SerializedModule};
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use super::symbol_export::symbol_name_for_instance_in_crate;
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use crate::{
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CachedModuleCodegen, CodegenResults, CompiledModule, CrateInfo, ModuleCodegen, ModuleKind,
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};
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use crate::traits::*;
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use jobserver::{Acquired, Client};
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use rustc_data_structures::fx::FxHashMap;
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use rustc_data_structures::profiling::SelfProfilerRef;
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use rustc_data_structures::profiling::TimingGuard;
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use rustc_data_structures::profiling::VerboseTimingGuard;
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use rustc_data_structures::sync::Lrc;
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use rustc_errors::emitter::Emitter;
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use rustc_errors::{DiagnosticId, FatalError, Handler, Level};
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use rustc_fs_util::link_or_copy;
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use rustc_hir::def_id::{CrateNum, LOCAL_CRATE};
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use rustc_incremental::{
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copy_cgu_workproduct_to_incr_comp_cache_dir, in_incr_comp_dir, in_incr_comp_dir_sess,
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};
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use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
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use rustc_middle::middle::cstore::EncodedMetadata;
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use rustc_middle::middle::exported_symbols::SymbolExportLevel;
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use rustc_middle::ty::TyCtxt;
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use rustc_session::cgu_reuse_tracker::CguReuseTracker;
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use rustc_session::config::{self, CrateType, Lto, OutputFilenames, OutputType};
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use rustc_session::config::{Passes, SanitizerSet, SwitchWithOptPath};
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use rustc_session::Session;
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use rustc_span::source_map::SourceMap;
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use rustc_span::symbol::{sym, Symbol};
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use rustc_span::{BytePos, FileName, InnerSpan, Pos, Span};
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use rustc_target::spec::{MergeFunctions, PanicStrategy};
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use std::any::Any;
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use std::fs;
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use std::io;
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use std::mem;
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use std::path::{Path, PathBuf};
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use std::str;
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use std::sync::mpsc::{channel, Receiver, Sender};
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use std::sync::Arc;
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use std::thread;
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const PRE_LTO_BC_EXT: &str = "pre-lto.bc";
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/// What kind of object file to emit.
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#[derive(Clone, Copy, PartialEq)]
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pub enum EmitObj {
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// No object file.
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None,
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// Just uncompressed llvm bitcode. Provides easy compatibility with
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// emscripten's ecc compiler, when used as the linker.
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Bitcode,
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// Object code, possibly augmented with a bitcode section.
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ObjectCode(BitcodeSection),
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}
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/// What kind of llvm bitcode section to embed in an object file.
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#[derive(Clone, Copy, PartialEq)]
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pub enum BitcodeSection {
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// No bitcode section.
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None,
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// A full, uncompressed bitcode section.
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Full,
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}
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/// Module-specific configuration for `optimize_and_codegen`.
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pub struct ModuleConfig {
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/// Names of additional optimization passes to run.
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pub passes: Vec<String>,
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/// Some(level) to optimize at a certain level, or None to run
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/// absolutely no optimizations (used for the metadata module).
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pub opt_level: Option<config::OptLevel>,
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/// Some(level) to optimize binary size, or None to not affect program size.
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pub opt_size: Option<config::OptLevel>,
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pub pgo_gen: SwitchWithOptPath,
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pub pgo_use: Option<PathBuf>,
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pub sanitizer: SanitizerSet,
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pub sanitizer_recover: SanitizerSet,
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pub sanitizer_memory_track_origins: usize,
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// Flags indicating which outputs to produce.
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pub emit_pre_lto_bc: bool,
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pub emit_no_opt_bc: bool,
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pub emit_bc: bool,
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pub emit_ir: bool,
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pub emit_asm: bool,
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pub emit_obj: EmitObj,
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pub bc_cmdline: String,
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// Miscellaneous flags. These are mostly copied from command-line
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// options.
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pub verify_llvm_ir: bool,
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pub no_prepopulate_passes: bool,
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pub no_builtins: bool,
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pub time_module: bool,
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pub vectorize_loop: bool,
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pub vectorize_slp: bool,
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pub merge_functions: bool,
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pub inline_threshold: Option<usize>,
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pub new_llvm_pass_manager: bool,
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pub emit_lifetime_markers: bool,
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}
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impl ModuleConfig {
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fn new(
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kind: ModuleKind,
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sess: &Session,
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no_builtins: bool,
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is_compiler_builtins: bool,
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) -> ModuleConfig {
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// If it's a regular module, use `$regular`, otherwise use `$other`.
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// `$regular` and `$other` are evaluated lazily.
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macro_rules! if_regular {
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($regular: expr, $other: expr) => {
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if let ModuleKind::Regular = kind { $regular } else { $other }
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};
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}
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let opt_level_and_size = if_regular!(Some(sess.opts.optimize), None);
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let save_temps = sess.opts.cg.save_temps;
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let should_emit_obj = sess.opts.output_types.contains_key(&OutputType::Exe)
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|| match kind {
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ModuleKind::Regular => sess.opts.output_types.contains_key(&OutputType::Object),
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ModuleKind::Allocator => false,
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ModuleKind::Metadata => sess.opts.output_types.contains_key(&OutputType::Metadata),
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};
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let emit_obj = if !should_emit_obj {
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EmitObj::None
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} else if sess.target.obj_is_bitcode
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|| (sess.opts.cg.linker_plugin_lto.enabled() && !no_builtins)
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{
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// This case is selected if the target uses objects as bitcode, or
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// if linker plugin LTO is enabled. In the linker plugin LTO case
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// the assumption is that the final link-step will read the bitcode
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// and convert it to object code. This may be done by either the
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// native linker or rustc itself.
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//
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// Note, however, that the linker-plugin-lto requested here is
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// explicitly ignored for `#![no_builtins]` crates. These crates are
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// specifically ignored by rustc's LTO passes and wouldn't work if
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// loaded into the linker. These crates define symbols that LLVM
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// lowers intrinsics to, and these symbol dependencies aren't known
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// until after codegen. As a result any crate marked
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// `#![no_builtins]` is assumed to not participate in LTO and
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// instead goes on to generate object code.
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EmitObj::Bitcode
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} else if need_bitcode_in_object(sess) {
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EmitObj::ObjectCode(BitcodeSection::Full)
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} else {
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EmitObj::ObjectCode(BitcodeSection::None)
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};
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ModuleConfig {
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passes: if_regular!(
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{
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let mut passes = sess.opts.cg.passes.clone();
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// compiler_builtins overrides the codegen-units settings,
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// which is incompatible with -Zprofile which requires that
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// only a single codegen unit is used per crate.
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if sess.opts.debugging_opts.profile && !is_compiler_builtins {
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passes.push("insert-gcov-profiling".to_owned());
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}
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// The rustc option `-Zinstrument_coverage` injects intrinsic calls to
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// `llvm.instrprof.increment()`, which requires the LLVM `instrprof` pass.
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if sess.opts.debugging_opts.instrument_coverage {
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passes.push("instrprof".to_owned());
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}
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passes
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},
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vec![]
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),
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opt_level: opt_level_and_size,
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opt_size: opt_level_and_size,
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pgo_gen: if_regular!(
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sess.opts.cg.profile_generate.clone(),
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SwitchWithOptPath::Disabled
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),
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pgo_use: if_regular!(sess.opts.cg.profile_use.clone(), None),
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sanitizer: if_regular!(sess.opts.debugging_opts.sanitizer, SanitizerSet::empty()),
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sanitizer_recover: if_regular!(
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sess.opts.debugging_opts.sanitizer_recover,
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SanitizerSet::empty()
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),
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sanitizer_memory_track_origins: if_regular!(
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sess.opts.debugging_opts.sanitizer_memory_track_origins,
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0
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),
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emit_pre_lto_bc: if_regular!(
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save_temps || need_pre_lto_bitcode_for_incr_comp(sess),
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false
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),
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emit_no_opt_bc: if_regular!(save_temps, false),
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emit_bc: if_regular!(
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save_temps || sess.opts.output_types.contains_key(&OutputType::Bitcode),
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save_temps
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),
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emit_ir: if_regular!(
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sess.opts.output_types.contains_key(&OutputType::LlvmAssembly),
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false
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),
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emit_asm: if_regular!(
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sess.opts.output_types.contains_key(&OutputType::Assembly),
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false
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),
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emit_obj,
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bc_cmdline: sess.target.bitcode_llvm_cmdline.clone(),
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verify_llvm_ir: sess.verify_llvm_ir(),
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no_prepopulate_passes: sess.opts.cg.no_prepopulate_passes,
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no_builtins: no_builtins || sess.target.no_builtins,
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// Exclude metadata and allocator modules from time_passes output,
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// since they throw off the "LLVM passes" measurement.
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time_module: if_regular!(true, false),
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// Copy what clang does by turning on loop vectorization at O2 and
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// slp vectorization at O3.
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vectorize_loop: !sess.opts.cg.no_vectorize_loops
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&& (sess.opts.optimize == config::OptLevel::Default
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|| sess.opts.optimize == config::OptLevel::Aggressive),
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vectorize_slp: !sess.opts.cg.no_vectorize_slp
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&& sess.opts.optimize == config::OptLevel::Aggressive,
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// Some targets (namely, NVPTX) interact badly with the
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// MergeFunctions pass. This is because MergeFunctions can generate
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// new function calls which may interfere with the target calling
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// convention; e.g. for the NVPTX target, PTX kernels should not
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// call other PTX kernels. MergeFunctions can also be configured to
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// generate aliases instead, but aliases are not supported by some
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// backends (again, NVPTX). Therefore, allow targets to opt out of
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// the MergeFunctions pass, but otherwise keep the pass enabled (at
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// O2 and O3) since it can be useful for reducing code size.
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merge_functions: match sess
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.opts
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.debugging_opts
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.merge_functions
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.unwrap_or(sess.target.merge_functions)
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{
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MergeFunctions::Disabled => false,
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MergeFunctions::Trampolines | MergeFunctions::Aliases => {
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sess.opts.optimize == config::OptLevel::Default
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|| sess.opts.optimize == config::OptLevel::Aggressive
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}
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},
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inline_threshold: sess.opts.cg.inline_threshold,
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new_llvm_pass_manager: sess.opts.debugging_opts.new_llvm_pass_manager,
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emit_lifetime_markers: sess.emit_lifetime_markers(),
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}
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}
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pub fn bitcode_needed(&self) -> bool {
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self.emit_bc
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|| self.emit_obj == EmitObj::Bitcode
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|| self.emit_obj == EmitObj::ObjectCode(BitcodeSection::Full)
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}
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}
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/// Configuration passed to the function returned by the `target_machine_factory`.
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pub struct TargetMachineFactoryConfig {
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/// Split DWARF is enabled in LLVM by checking that `TM.MCOptions.SplitDwarfFile` isn't empty,
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/// so the path to the dwarf object has to be provided when we create the target machine.
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/// This can be ignored by backends which do not need it for their Split DWARF support.
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pub split_dwarf_file: Option<PathBuf>,
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}
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impl TargetMachineFactoryConfig {
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pub fn new(
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cgcx: &CodegenContext<impl WriteBackendMethods>,
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module_name: &str,
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) -> TargetMachineFactoryConfig {
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let split_dwarf_file = if cgcx.target_can_use_split_dwarf {
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cgcx.output_filenames.split_dwarf_path(cgcx.split_debuginfo, Some(module_name))
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} else {
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None
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};
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TargetMachineFactoryConfig { split_dwarf_file }
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}
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}
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pub type TargetMachineFactoryFn<B> = Arc<
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dyn Fn(TargetMachineFactoryConfig) -> Result<<B as WriteBackendMethods>::TargetMachine, String>
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+ Send
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+ Sync,
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>;
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pub type ExportedSymbols = FxHashMap<CrateNum, Arc<Vec<(String, SymbolExportLevel)>>>;
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/// Additional resources used by optimize_and_codegen (not module specific)
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#[derive(Clone)]
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pub struct CodegenContext<B: WriteBackendMethods> {
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// Resources needed when running LTO
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pub backend: B,
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pub prof: SelfProfilerRef,
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pub lto: Lto,
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pub no_landing_pads: bool,
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pub save_temps: bool,
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pub fewer_names: bool,
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pub exported_symbols: Option<Arc<ExportedSymbols>>,
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pub opts: Arc<config::Options>,
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pub crate_types: Vec<CrateType>,
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pub each_linked_rlib_for_lto: Vec<(CrateNum, PathBuf)>,
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pub output_filenames: Arc<OutputFilenames>,
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pub regular_module_config: Arc<ModuleConfig>,
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pub metadata_module_config: Arc<ModuleConfig>,
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pub allocator_module_config: Arc<ModuleConfig>,
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pub tm_factory: TargetMachineFactoryFn<B>,
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pub msvc_imps_needed: bool,
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pub is_pe_coff: bool,
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pub target_can_use_split_dwarf: bool,
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pub target_pointer_width: u32,
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pub target_arch: String,
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pub debuginfo: config::DebugInfo,
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pub split_debuginfo: rustc_target::spec::SplitDebuginfo,
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// Number of cgus excluding the allocator/metadata modules
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pub total_cgus: usize,
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// Handler to use for diagnostics produced during codegen.
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pub diag_emitter: SharedEmitter,
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// LLVM optimizations for which we want to print remarks.
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pub remark: Passes,
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// Worker thread number
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pub worker: usize,
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// The incremental compilation session directory, or None if we are not
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// compiling incrementally
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pub incr_comp_session_dir: Option<PathBuf>,
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// Used to update CGU re-use information during the thinlto phase.
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pub cgu_reuse_tracker: CguReuseTracker,
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// Channel back to the main control thread to send messages to
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pub coordinator_send: Sender<Box<dyn Any + Send>>,
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}
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impl<B: WriteBackendMethods> CodegenContext<B> {
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pub fn create_diag_handler(&self) -> Handler {
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Handler::with_emitter(true, None, Box::new(self.diag_emitter.clone()))
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}
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pub fn config(&self, kind: ModuleKind) -> &ModuleConfig {
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match kind {
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ModuleKind::Regular => &self.regular_module_config,
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ModuleKind::Metadata => &self.metadata_module_config,
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ModuleKind::Allocator => &self.allocator_module_config,
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}
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}
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}
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fn generate_lto_work<B: ExtraBackendMethods>(
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cgcx: &CodegenContext<B>,
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needs_fat_lto: Vec<FatLTOInput<B>>,
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needs_thin_lto: Vec<(String, B::ThinBuffer)>,
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import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>,
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) -> Vec<(WorkItem<B>, u64)> {
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let _prof_timer = cgcx.prof.generic_activity("codegen_generate_lto_work");
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let (lto_modules, copy_jobs) = if !needs_fat_lto.is_empty() {
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assert!(needs_thin_lto.is_empty());
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let lto_module =
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B::run_fat_lto(cgcx, needs_fat_lto, import_only_modules).unwrap_or_else(|e| e.raise());
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(vec![lto_module], vec![])
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} else {
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assert!(needs_fat_lto.is_empty());
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B::run_thin_lto(cgcx, needs_thin_lto, import_only_modules).unwrap_or_else(|e| e.raise())
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};
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lto_modules
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.into_iter()
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.map(|module| {
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let cost = module.cost();
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(WorkItem::LTO(module), cost)
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})
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.chain(copy_jobs.into_iter().map(|wp| {
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(
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WorkItem::CopyPostLtoArtifacts(CachedModuleCodegen {
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name: wp.cgu_name.clone(),
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source: wp,
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}),
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0,
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)
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}))
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.collect()
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}
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pub struct CompiledModules {
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pub modules: Vec<CompiledModule>,
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pub metadata_module: Option<CompiledModule>,
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pub allocator_module: Option<CompiledModule>,
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}
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fn need_bitcode_in_object(sess: &Session) -> bool {
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let requested_for_rlib = sess.opts.cg.embed_bitcode
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&& sess.crate_types().contains(&CrateType::Rlib)
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&& sess.opts.output_types.contains_key(&OutputType::Exe);
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let forced_by_target = sess.target.forces_embed_bitcode;
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requested_for_rlib || forced_by_target
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}
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fn need_pre_lto_bitcode_for_incr_comp(sess: &Session) -> bool {
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if sess.opts.incremental.is_none() {
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return false;
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}
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match sess.lto() {
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Lto::No => false,
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Lto::Fat | Lto::Thin | Lto::ThinLocal => true,
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}
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}
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pub fn start_async_codegen<B: ExtraBackendMethods>(
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backend: B,
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tcx: TyCtxt<'_>,
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metadata: EncodedMetadata,
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total_cgus: usize,
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) -> OngoingCodegen<B> {
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let (coordinator_send, coordinator_receive) = channel();
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let sess = tcx.sess;
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let crate_name = tcx.crate_name(LOCAL_CRATE);
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let crate_attrs = tcx.hir().attrs(rustc_hir::CRATE_HIR_ID);
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let no_builtins = tcx.sess.contains_name(crate_attrs, sym::no_builtins);
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let is_compiler_builtins = tcx.sess.contains_name(crate_attrs, sym::compiler_builtins);
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let subsystem = tcx.sess.first_attr_value_str_by_name(crate_attrs, sym::windows_subsystem);
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let windows_subsystem = subsystem.map(|subsystem| {
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if subsystem != sym::windows && subsystem != sym::console {
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tcx.sess.fatal(&format!(
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"invalid windows subsystem `{}`, only \
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`windows` and `console` are allowed",
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subsystem
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));
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}
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subsystem.to_string()
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});
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let linker_info = LinkerInfo::new(tcx);
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let crate_info = CrateInfo::new(tcx);
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let regular_config =
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ModuleConfig::new(ModuleKind::Regular, sess, no_builtins, is_compiler_builtins);
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let metadata_config =
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ModuleConfig::new(ModuleKind::Metadata, sess, no_builtins, is_compiler_builtins);
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let allocator_config =
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ModuleConfig::new(ModuleKind::Allocator, sess, no_builtins, is_compiler_builtins);
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let (shared_emitter, shared_emitter_main) = SharedEmitter::new();
|
||
let (codegen_worker_send, codegen_worker_receive) = channel();
|
||
|
||
let coordinator_thread = start_executing_work(
|
||
backend.clone(),
|
||
tcx,
|
||
&crate_info,
|
||
shared_emitter,
|
||
codegen_worker_send,
|
||
coordinator_receive,
|
||
total_cgus,
|
||
sess.jobserver.clone(),
|
||
Arc::new(regular_config),
|
||
Arc::new(metadata_config),
|
||
Arc::new(allocator_config),
|
||
coordinator_send.clone(),
|
||
);
|
||
|
||
OngoingCodegen {
|
||
backend,
|
||
crate_name,
|
||
metadata,
|
||
windows_subsystem,
|
||
linker_info,
|
||
crate_info,
|
||
|
||
coordinator_send,
|
||
codegen_worker_receive,
|
||
shared_emitter_main,
|
||
future: coordinator_thread,
|
||
output_filenames: tcx.output_filenames(LOCAL_CRATE),
|
||
}
|
||
}
|
||
|
||
fn copy_all_cgu_workproducts_to_incr_comp_cache_dir(
|
||
sess: &Session,
|
||
compiled_modules: &CompiledModules,
|
||
) -> FxHashMap<WorkProductId, WorkProduct> {
|
||
let mut work_products = FxHashMap::default();
|
||
|
||
if sess.opts.incremental.is_none() {
|
||
return work_products;
|
||
}
|
||
|
||
let _timer = sess.timer("copy_all_cgu_workproducts_to_incr_comp_cache_dir");
|
||
|
||
for module in compiled_modules.modules.iter().filter(|m| m.kind == ModuleKind::Regular) {
|
||
let path = module.object.as_ref().cloned();
|
||
|
||
if let Some((id, product)) =
|
||
copy_cgu_workproduct_to_incr_comp_cache_dir(sess, &module.name, &path)
|
||
{
|
||
work_products.insert(id, product);
|
||
}
|
||
}
|
||
|
||
work_products
|
||
}
|
||
|
||
fn produce_final_output_artifacts(
|
||
sess: &Session,
|
||
compiled_modules: &CompiledModules,
|
||
crate_output: &OutputFilenames,
|
||
) {
|
||
let mut user_wants_bitcode = false;
|
||
let mut user_wants_objects = false;
|
||
|
||
// Produce final compile outputs.
|
||
let copy_gracefully = |from: &Path, to: &Path| {
|
||
if let Err(e) = fs::copy(from, to) {
|
||
sess.err(&format!("could not copy {:?} to {:?}: {}", from, to, e));
|
||
}
|
||
};
|
||
|
||
let copy_if_one_unit = |output_type: OutputType, keep_numbered: bool| {
|
||
if compiled_modules.modules.len() == 1 {
|
||
// 1) Only one codegen unit. In this case it's no difficulty
|
||
// to copy `foo.0.x` to `foo.x`.
|
||
let module_name = Some(&compiled_modules.modules[0].name[..]);
|
||
let path = crate_output.temp_path(output_type, module_name);
|
||
copy_gracefully(&path, &crate_output.path(output_type));
|
||
if !sess.opts.cg.save_temps && !keep_numbered {
|
||
// The user just wants `foo.x`, not `foo.#module-name#.x`.
|
||
ensure_removed(sess.diagnostic(), &path);
|
||
}
|
||
} else {
|
||
let ext = crate_output
|
||
.temp_path(output_type, None)
|
||
.extension()
|
||
.unwrap()
|
||
.to_str()
|
||
.unwrap()
|
||
.to_owned();
|
||
|
||
if crate_output.outputs.contains_key(&output_type) {
|
||
// 2) Multiple codegen units, with `--emit foo=some_name`. We have
|
||
// no good solution for this case, so warn the user.
|
||
sess.warn(&format!(
|
||
"ignoring emit path because multiple .{} files \
|
||
were produced",
|
||
ext
|
||
));
|
||
} else if crate_output.single_output_file.is_some() {
|
||
// 3) Multiple codegen units, with `-o some_name`. We have
|
||
// no good solution for this case, so warn the user.
|
||
sess.warn(&format!(
|
||
"ignoring -o because multiple .{} files \
|
||
were produced",
|
||
ext
|
||
));
|
||
} else {
|
||
// 4) Multiple codegen units, but no explicit name. We
|
||
// just leave the `foo.0.x` files in place.
|
||
// (We don't have to do any work in this case.)
|
||
}
|
||
}
|
||
};
|
||
|
||
// Flag to indicate whether the user explicitly requested bitcode.
|
||
// Otherwise, we produced it only as a temporary output, and will need
|
||
// to get rid of it.
|
||
for output_type in crate_output.outputs.keys() {
|
||
match *output_type {
|
||
OutputType::Bitcode => {
|
||
user_wants_bitcode = true;
|
||
// Copy to .bc, but always keep the .0.bc. There is a later
|
||
// check to figure out if we should delete .0.bc files, or keep
|
||
// them for making an rlib.
|
||
copy_if_one_unit(OutputType::Bitcode, true);
|
||
}
|
||
OutputType::LlvmAssembly => {
|
||
copy_if_one_unit(OutputType::LlvmAssembly, false);
|
||
}
|
||
OutputType::Assembly => {
|
||
copy_if_one_unit(OutputType::Assembly, false);
|
||
}
|
||
OutputType::Object => {
|
||
user_wants_objects = true;
|
||
copy_if_one_unit(OutputType::Object, true);
|
||
}
|
||
OutputType::Mir | OutputType::Metadata | OutputType::Exe | OutputType::DepInfo => {}
|
||
}
|
||
}
|
||
|
||
// Clean up unwanted temporary files.
|
||
|
||
// We create the following files by default:
|
||
// - #crate#.#module-name#.bc
|
||
// - #crate#.#module-name#.o
|
||
// - #crate#.crate.metadata.bc
|
||
// - #crate#.crate.metadata.o
|
||
// - #crate#.o (linked from crate.##.o)
|
||
// - #crate#.bc (copied from crate.##.bc)
|
||
// We may create additional files if requested by the user (through
|
||
// `-C save-temps` or `--emit=` flags).
|
||
|
||
if !sess.opts.cg.save_temps {
|
||
// Remove the temporary .#module-name#.o objects. If the user didn't
|
||
// explicitly request bitcode (with --emit=bc), and the bitcode is not
|
||
// needed for building an rlib, then we must remove .#module-name#.bc as
|
||
// well.
|
||
|
||
// Specific rules for keeping .#module-name#.bc:
|
||
// - If the user requested bitcode (`user_wants_bitcode`), and
|
||
// codegen_units > 1, then keep it.
|
||
// - If the user requested bitcode but codegen_units == 1, then we
|
||
// can toss .#module-name#.bc because we copied it to .bc earlier.
|
||
// - If we're not building an rlib and the user didn't request
|
||
// bitcode, then delete .#module-name#.bc.
|
||
// If you change how this works, also update back::link::link_rlib,
|
||
// where .#module-name#.bc files are (maybe) deleted after making an
|
||
// rlib.
|
||
let needs_crate_object = crate_output.outputs.contains_key(&OutputType::Exe);
|
||
|
||
let keep_numbered_bitcode = user_wants_bitcode && sess.codegen_units() > 1;
|
||
|
||
let keep_numbered_objects =
|
||
needs_crate_object || (user_wants_objects && sess.codegen_units() > 1);
|
||
|
||
for module in compiled_modules.modules.iter() {
|
||
if let Some(ref path) = module.object {
|
||
if !keep_numbered_objects {
|
||
ensure_removed(sess.diagnostic(), path);
|
||
}
|
||
}
|
||
|
||
if let Some(ref path) = module.dwarf_object {
|
||
if !keep_numbered_objects {
|
||
ensure_removed(sess.diagnostic(), path);
|
||
}
|
||
}
|
||
|
||
if let Some(ref path) = module.bytecode {
|
||
if !keep_numbered_bitcode {
|
||
ensure_removed(sess.diagnostic(), path);
|
||
}
|
||
}
|
||
}
|
||
|
||
if !user_wants_bitcode {
|
||
if let Some(ref metadata_module) = compiled_modules.metadata_module {
|
||
if let Some(ref path) = metadata_module.bytecode {
|
||
ensure_removed(sess.diagnostic(), &path);
|
||
}
|
||
}
|
||
|
||
if let Some(ref allocator_module) = compiled_modules.allocator_module {
|
||
if let Some(ref path) = allocator_module.bytecode {
|
||
ensure_removed(sess.diagnostic(), path);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
// We leave the following files around by default:
|
||
// - #crate#.o
|
||
// - #crate#.crate.metadata.o
|
||
// - #crate#.bc
|
||
// These are used in linking steps and will be cleaned up afterward.
|
||
}
|
||
|
||
pub enum WorkItem<B: WriteBackendMethods> {
|
||
/// Optimize a newly codegened, totally unoptimized module.
|
||
Optimize(ModuleCodegen<B::Module>),
|
||
/// Copy the post-LTO artifacts from the incremental cache to the output
|
||
/// directory.
|
||
CopyPostLtoArtifacts(CachedModuleCodegen),
|
||
/// Performs (Thin)LTO on the given module.
|
||
LTO(lto::LtoModuleCodegen<B>),
|
||
}
|
||
|
||
impl<B: WriteBackendMethods> WorkItem<B> {
|
||
pub fn module_kind(&self) -> ModuleKind {
|
||
match *self {
|
||
WorkItem::Optimize(ref m) => m.kind,
|
||
WorkItem::CopyPostLtoArtifacts(_) | WorkItem::LTO(_) => ModuleKind::Regular,
|
||
}
|
||
}
|
||
|
||
fn start_profiling<'a>(&self, cgcx: &'a CodegenContext<B>) -> TimingGuard<'a> {
|
||
match *self {
|
||
WorkItem::Optimize(ref m) => {
|
||
cgcx.prof.generic_activity_with_arg("codegen_module_optimize", &m.name[..])
|
||
}
|
||
WorkItem::CopyPostLtoArtifacts(ref m) => cgcx
|
||
.prof
|
||
.generic_activity_with_arg("codegen_copy_artifacts_from_incr_cache", &m.name[..]),
|
||
WorkItem::LTO(ref m) => {
|
||
cgcx.prof.generic_activity_with_arg("codegen_module_perform_lto", m.name())
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Generate a short description of this work item suitable for use as a thread name.
|
||
fn short_description(&self) -> String {
|
||
// `pthread_setname()` on *nix is limited to 15 characters and longer names are ignored.
|
||
// Use very short descriptions in this case to maximize the space available for the module name.
|
||
// Windows does not have that limitation so use slightly more descriptive names there.
|
||
match self {
|
||
WorkItem::Optimize(m) => {
|
||
#[cfg(windows)]
|
||
return format!("optimize module {}", m.name);
|
||
#[cfg(not(windows))]
|
||
return format!("opt {}", m.name);
|
||
}
|
||
WorkItem::CopyPostLtoArtifacts(m) => {
|
||
#[cfg(windows)]
|
||
return format!("copy LTO artifacts for {}", m.name);
|
||
#[cfg(not(windows))]
|
||
return format!("copy {}", m.name);
|
||
}
|
||
WorkItem::LTO(m) => {
|
||
#[cfg(windows)]
|
||
return format!("LTO module {}", m.name());
|
||
#[cfg(not(windows))]
|
||
return format!("LTO {}", m.name());
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
enum WorkItemResult<B: WriteBackendMethods> {
|
||
Compiled(CompiledModule),
|
||
NeedsLink(ModuleCodegen<B::Module>),
|
||
NeedsFatLTO(FatLTOInput<B>),
|
||
NeedsThinLTO(String, B::ThinBuffer),
|
||
}
|
||
|
||
pub enum FatLTOInput<B: WriteBackendMethods> {
|
||
Serialized { name: String, buffer: B::ModuleBuffer },
|
||
InMemory(ModuleCodegen<B::Module>),
|
||
}
|
||
|
||
fn execute_work_item<B: ExtraBackendMethods>(
|
||
cgcx: &CodegenContext<B>,
|
||
work_item: WorkItem<B>,
|
||
) -> Result<WorkItemResult<B>, FatalError> {
|
||
let module_config = cgcx.config(work_item.module_kind());
|
||
|
||
match work_item {
|
||
WorkItem::Optimize(module) => execute_optimize_work_item(cgcx, module, module_config),
|
||
WorkItem::CopyPostLtoArtifacts(module) => {
|
||
Ok(execute_copy_from_cache_work_item(cgcx, module, module_config))
|
||
}
|
||
WorkItem::LTO(module) => execute_lto_work_item(cgcx, module, module_config),
|
||
}
|
||
}
|
||
|
||
// Actual LTO type we end up choosing based on multiple factors.
|
||
pub enum ComputedLtoType {
|
||
No,
|
||
Thin,
|
||
Fat,
|
||
}
|
||
|
||
pub fn compute_per_cgu_lto_type(
|
||
sess_lto: &Lto,
|
||
opts: &config::Options,
|
||
sess_crate_types: &[CrateType],
|
||
module_kind: ModuleKind,
|
||
) -> ComputedLtoType {
|
||
// Metadata modules never participate in LTO regardless of the lto
|
||
// settings.
|
||
if module_kind == ModuleKind::Metadata {
|
||
return ComputedLtoType::No;
|
||
}
|
||
|
||
// If the linker does LTO, we don't have to do it. Note that we
|
||
// keep doing full LTO, if it is requested, as not to break the
|
||
// assumption that the output will be a single module.
|
||
let linker_does_lto = opts.cg.linker_plugin_lto.enabled();
|
||
|
||
// When we're automatically doing ThinLTO for multi-codegen-unit
|
||
// builds we don't actually want to LTO the allocator modules if
|
||
// it shows up. This is due to various linker shenanigans that
|
||
// we'll encounter later.
|
||
let is_allocator = module_kind == ModuleKind::Allocator;
|
||
|
||
// We ignore a request for full crate grath LTO if the cate type
|
||
// is only an rlib, as there is no full crate graph to process,
|
||
// that'll happen later.
|
||
//
|
||
// This use case currently comes up primarily for targets that
|
||
// require LTO so the request for LTO is always unconditionally
|
||
// passed down to the backend, but we don't actually want to do
|
||
// anything about it yet until we've got a final product.
|
||
let is_rlib = sess_crate_types.len() == 1 && sess_crate_types[0] == CrateType::Rlib;
|
||
|
||
match sess_lto {
|
||
Lto::ThinLocal if !linker_does_lto && !is_allocator => ComputedLtoType::Thin,
|
||
Lto::Thin if !linker_does_lto && !is_rlib => ComputedLtoType::Thin,
|
||
Lto::Fat if !is_rlib => ComputedLtoType::Fat,
|
||
_ => ComputedLtoType::No,
|
||
}
|
||
}
|
||
|
||
fn execute_optimize_work_item<B: ExtraBackendMethods>(
|
||
cgcx: &CodegenContext<B>,
|
||
module: ModuleCodegen<B::Module>,
|
||
module_config: &ModuleConfig,
|
||
) -> Result<WorkItemResult<B>, FatalError> {
|
||
let diag_handler = cgcx.create_diag_handler();
|
||
|
||
unsafe {
|
||
B::optimize(cgcx, &diag_handler, &module, module_config)?;
|
||
}
|
||
|
||
// After we've done the initial round of optimizations we need to
|
||
// decide whether to synchronously codegen this module or ship it
|
||
// back to the coordinator thread for further LTO processing (which
|
||
// has to wait for all the initial modules to be optimized).
|
||
|
||
let lto_type = compute_per_cgu_lto_type(&cgcx.lto, &cgcx.opts, &cgcx.crate_types, module.kind);
|
||
|
||
// If we're doing some form of incremental LTO then we need to be sure to
|
||
// save our module to disk first.
|
||
let bitcode = if cgcx.config(module.kind).emit_pre_lto_bc {
|
||
let filename = pre_lto_bitcode_filename(&module.name);
|
||
cgcx.incr_comp_session_dir.as_ref().map(|path| path.join(&filename))
|
||
} else {
|
||
None
|
||
};
|
||
|
||
match lto_type {
|
||
ComputedLtoType::No => finish_intra_module_work(cgcx, module, module_config),
|
||
ComputedLtoType::Thin => {
|
||
let (name, thin_buffer) = B::prepare_thin(module);
|
||
if let Some(path) = bitcode {
|
||
fs::write(&path, thin_buffer.data()).unwrap_or_else(|e| {
|
||
panic!("Error writing pre-lto-bitcode file `{}`: {}", path.display(), e);
|
||
});
|
||
}
|
||
Ok(WorkItemResult::NeedsThinLTO(name, thin_buffer))
|
||
}
|
||
ComputedLtoType::Fat => match bitcode {
|
||
Some(path) => {
|
||
let (name, buffer) = B::serialize_module(module);
|
||
fs::write(&path, buffer.data()).unwrap_or_else(|e| {
|
||
panic!("Error writing pre-lto-bitcode file `{}`: {}", path.display(), e);
|
||
});
|
||
Ok(WorkItemResult::NeedsFatLTO(FatLTOInput::Serialized { name, buffer }))
|
||
}
|
||
None => Ok(WorkItemResult::NeedsFatLTO(FatLTOInput::InMemory(module))),
|
||
},
|
||
}
|
||
}
|
||
|
||
fn execute_copy_from_cache_work_item<B: ExtraBackendMethods>(
|
||
cgcx: &CodegenContext<B>,
|
||
module: CachedModuleCodegen,
|
||
module_config: &ModuleConfig,
|
||
) -> WorkItemResult<B> {
|
||
let incr_comp_session_dir = cgcx.incr_comp_session_dir.as_ref().unwrap();
|
||
let mut object = None;
|
||
if let Some(saved_file) = module.source.saved_file {
|
||
let obj_out = cgcx.output_filenames.temp_path(OutputType::Object, Some(&module.name));
|
||
object = Some(obj_out.clone());
|
||
let source_file = in_incr_comp_dir(&incr_comp_session_dir, &saved_file);
|
||
debug!(
|
||
"copying pre-existing module `{}` from {:?} to {}",
|
||
module.name,
|
||
source_file,
|
||
obj_out.display()
|
||
);
|
||
if let Err(err) = link_or_copy(&source_file, &obj_out) {
|
||
let diag_handler = cgcx.create_diag_handler();
|
||
diag_handler.err(&format!(
|
||
"unable to copy {} to {}: {}",
|
||
source_file.display(),
|
||
obj_out.display(),
|
||
err
|
||
));
|
||
}
|
||
}
|
||
|
||
assert_eq!(object.is_some(), module_config.emit_obj != EmitObj::None);
|
||
|
||
WorkItemResult::Compiled(CompiledModule {
|
||
name: module.name,
|
||
kind: ModuleKind::Regular,
|
||
object,
|
||
dwarf_object: None,
|
||
bytecode: None,
|
||
})
|
||
}
|
||
|
||
fn execute_lto_work_item<B: ExtraBackendMethods>(
|
||
cgcx: &CodegenContext<B>,
|
||
mut module: lto::LtoModuleCodegen<B>,
|
||
module_config: &ModuleConfig,
|
||
) -> Result<WorkItemResult<B>, FatalError> {
|
||
let module = unsafe { module.optimize(cgcx)? };
|
||
finish_intra_module_work(cgcx, module, module_config)
|
||
}
|
||
|
||
fn finish_intra_module_work<B: ExtraBackendMethods>(
|
||
cgcx: &CodegenContext<B>,
|
||
module: ModuleCodegen<B::Module>,
|
||
module_config: &ModuleConfig,
|
||
) -> Result<WorkItemResult<B>, FatalError> {
|
||
let diag_handler = cgcx.create_diag_handler();
|
||
|
||
if !cgcx.opts.debugging_opts.combine_cgu
|
||
|| module.kind == ModuleKind::Metadata
|
||
|| module.kind == ModuleKind::Allocator
|
||
{
|
||
let module = unsafe { B::codegen(cgcx, &diag_handler, module, module_config)? };
|
||
Ok(WorkItemResult::Compiled(module))
|
||
} else {
|
||
Ok(WorkItemResult::NeedsLink(module))
|
||
}
|
||
}
|
||
|
||
pub enum Message<B: WriteBackendMethods> {
|
||
Token(io::Result<Acquired>),
|
||
NeedsFatLTO {
|
||
result: FatLTOInput<B>,
|
||
worker_id: usize,
|
||
},
|
||
NeedsThinLTO {
|
||
name: String,
|
||
thin_buffer: B::ThinBuffer,
|
||
worker_id: usize,
|
||
},
|
||
NeedsLink {
|
||
module: ModuleCodegen<B::Module>,
|
||
worker_id: usize,
|
||
},
|
||
Done {
|
||
result: Result<CompiledModule, Option<WorkerFatalError>>,
|
||
worker_id: usize,
|
||
},
|
||
CodegenDone {
|
||
llvm_work_item: WorkItem<B>,
|
||
cost: u64,
|
||
},
|
||
AddImportOnlyModule {
|
||
module_data: SerializedModule<B::ModuleBuffer>,
|
||
work_product: WorkProduct,
|
||
},
|
||
CodegenComplete,
|
||
CodegenItem,
|
||
CodegenAborted,
|
||
}
|
||
|
||
struct Diagnostic {
|
||
msg: String,
|
||
code: Option<DiagnosticId>,
|
||
lvl: Level,
|
||
}
|
||
|
||
#[derive(PartialEq, Clone, Copy, Debug)]
|
||
enum MainThreadWorkerState {
|
||
Idle,
|
||
Codegenning,
|
||
LLVMing,
|
||
}
|
||
|
||
fn start_executing_work<B: ExtraBackendMethods>(
|
||
backend: B,
|
||
tcx: TyCtxt<'_>,
|
||
crate_info: &CrateInfo,
|
||
shared_emitter: SharedEmitter,
|
||
codegen_worker_send: Sender<Message<B>>,
|
||
coordinator_receive: Receiver<Box<dyn Any + Send>>,
|
||
total_cgus: usize,
|
||
jobserver: Client,
|
||
regular_config: Arc<ModuleConfig>,
|
||
metadata_config: Arc<ModuleConfig>,
|
||
allocator_config: Arc<ModuleConfig>,
|
||
tx_to_llvm_workers: Sender<Box<dyn Any + Send>>,
|
||
) -> thread::JoinHandle<Result<CompiledModules, ()>> {
|
||
let coordinator_send = tx_to_llvm_workers;
|
||
let sess = tcx.sess;
|
||
|
||
// Compute the set of symbols we need to retain when doing LTO (if we need to)
|
||
let exported_symbols = {
|
||
let mut exported_symbols = FxHashMap::default();
|
||
|
||
let copy_symbols = |cnum| {
|
||
let symbols = tcx
|
||
.exported_symbols(cnum)
|
||
.iter()
|
||
.map(|&(s, lvl)| (symbol_name_for_instance_in_crate(tcx, s, cnum), lvl))
|
||
.collect();
|
||
Arc::new(symbols)
|
||
};
|
||
|
||
match sess.lto() {
|
||
Lto::No => None,
|
||
Lto::ThinLocal => {
|
||
exported_symbols.insert(LOCAL_CRATE, copy_symbols(LOCAL_CRATE));
|
||
Some(Arc::new(exported_symbols))
|
||
}
|
||
Lto::Fat | Lto::Thin => {
|
||
exported_symbols.insert(LOCAL_CRATE, copy_symbols(LOCAL_CRATE));
|
||
for &cnum in tcx.crates().iter() {
|
||
exported_symbols.insert(cnum, copy_symbols(cnum));
|
||
}
|
||
Some(Arc::new(exported_symbols))
|
||
}
|
||
}
|
||
};
|
||
|
||
// First up, convert our jobserver into a helper thread so we can use normal
|
||
// mpsc channels to manage our messages and such.
|
||
// After we've requested tokens then we'll, when we can,
|
||
// get tokens on `coordinator_receive` which will
|
||
// get managed in the main loop below.
|
||
let coordinator_send2 = coordinator_send.clone();
|
||
let helper = jobserver
|
||
.into_helper_thread(move |token| {
|
||
drop(coordinator_send2.send(Box::new(Message::Token::<B>(token))));
|
||
})
|
||
.expect("failed to spawn helper thread");
|
||
|
||
let mut each_linked_rlib_for_lto = Vec::new();
|
||
drop(link::each_linked_rlib(crate_info, &mut |cnum, path| {
|
||
if link::ignored_for_lto(sess, crate_info, cnum) {
|
||
return;
|
||
}
|
||
each_linked_rlib_for_lto.push((cnum, path.to_path_buf()));
|
||
}));
|
||
|
||
let ol = if tcx.sess.opts.debugging_opts.no_codegen
|
||
|| !tcx.sess.opts.output_types.should_codegen()
|
||
{
|
||
// If we know that we won’t be doing codegen, create target machines without optimisation.
|
||
config::OptLevel::No
|
||
} else {
|
||
tcx.backend_optimization_level(LOCAL_CRATE)
|
||
};
|
||
let cgcx = CodegenContext::<B> {
|
||
backend: backend.clone(),
|
||
crate_types: sess.crate_types().to_vec(),
|
||
each_linked_rlib_for_lto,
|
||
lto: sess.lto(),
|
||
no_landing_pads: sess.panic_strategy() == PanicStrategy::Abort,
|
||
fewer_names: sess.fewer_names(),
|
||
save_temps: sess.opts.cg.save_temps,
|
||
opts: Arc::new(sess.opts.clone()),
|
||
prof: sess.prof.clone(),
|
||
exported_symbols,
|
||
remark: sess.opts.cg.remark.clone(),
|
||
worker: 0,
|
||
incr_comp_session_dir: sess.incr_comp_session_dir_opt().map(|r| r.clone()),
|
||
cgu_reuse_tracker: sess.cgu_reuse_tracker.clone(),
|
||
coordinator_send,
|
||
diag_emitter: shared_emitter.clone(),
|
||
output_filenames: tcx.output_filenames(LOCAL_CRATE),
|
||
regular_module_config: regular_config,
|
||
metadata_module_config: metadata_config,
|
||
allocator_module_config: allocator_config,
|
||
tm_factory: backend.target_machine_factory(tcx.sess, ol),
|
||
total_cgus,
|
||
msvc_imps_needed: msvc_imps_needed(tcx),
|
||
is_pe_coff: tcx.sess.target.is_like_windows,
|
||
target_can_use_split_dwarf: tcx.sess.target_can_use_split_dwarf(),
|
||
target_pointer_width: tcx.sess.target.pointer_width,
|
||
target_arch: tcx.sess.target.arch.clone(),
|
||
debuginfo: tcx.sess.opts.debuginfo,
|
||
split_debuginfo: tcx.sess.split_debuginfo(),
|
||
};
|
||
|
||
// This is the "main loop" of parallel work happening for parallel codegen.
|
||
// It's here that we manage parallelism, schedule work, and work with
|
||
// messages coming from clients.
|
||
//
|
||
// There are a few environmental pre-conditions that shape how the system
|
||
// is set up:
|
||
//
|
||
// - Error reporting only can happen on the main thread because that's the
|
||
// only place where we have access to the compiler `Session`.
|
||
// - LLVM work can be done on any thread.
|
||
// - Codegen can only happen on the main thread.
|
||
// - Each thread doing substantial work most be in possession of a `Token`
|
||
// from the `Jobserver`.
|
||
// - The compiler process always holds one `Token`. Any additional `Tokens`
|
||
// have to be requested from the `Jobserver`.
|
||
//
|
||
// Error Reporting
|
||
// ===============
|
||
// The error reporting restriction is handled separately from the rest: We
|
||
// set up a `SharedEmitter` the holds an open channel to the main thread.
|
||
// When an error occurs on any thread, the shared emitter will send the
|
||
// error message to the receiver main thread (`SharedEmitterMain`). The
|
||
// main thread will periodically query this error message queue and emit
|
||
// any error messages it has received. It might even abort compilation if
|
||
// has received a fatal error. In this case we rely on all other threads
|
||
// being torn down automatically with the main thread.
|
||
// Since the main thread will often be busy doing codegen work, error
|
||
// reporting will be somewhat delayed, since the message queue can only be
|
||
// checked in between to work packages.
|
||
//
|
||
// Work Processing Infrastructure
|
||
// ==============================
|
||
// The work processing infrastructure knows three major actors:
|
||
//
|
||
// - the coordinator thread,
|
||
// - the main thread, and
|
||
// - LLVM worker threads
|
||
//
|
||
// The coordinator thread is running a message loop. It instructs the main
|
||
// thread about what work to do when, and it will spawn off LLVM worker
|
||
// threads as open LLVM WorkItems become available.
|
||
//
|
||
// The job of the main thread is to codegen CGUs into LLVM work package
|
||
// (since the main thread is the only thread that can do this). The main
|
||
// thread will block until it receives a message from the coordinator, upon
|
||
// which it will codegen one CGU, send it to the coordinator and block
|
||
// again. This way the coordinator can control what the main thread is
|
||
// doing.
|
||
//
|
||
// The coordinator keeps a queue of LLVM WorkItems, and when a `Token` is
|
||
// available, it will spawn off a new LLVM worker thread and let it process
|
||
// that a WorkItem. When a LLVM worker thread is done with its WorkItem,
|
||
// it will just shut down, which also frees all resources associated with
|
||
// the given LLVM module, and sends a message to the coordinator that the
|
||
// has been completed.
|
||
//
|
||
// Work Scheduling
|
||
// ===============
|
||
// The scheduler's goal is to minimize the time it takes to complete all
|
||
// work there is, however, we also want to keep memory consumption low
|
||
// if possible. These two goals are at odds with each other: If memory
|
||
// consumption were not an issue, we could just let the main thread produce
|
||
// LLVM WorkItems at full speed, assuring maximal utilization of
|
||
// Tokens/LLVM worker threads. However, since codegen usual is faster
|
||
// than LLVM processing, the queue of LLVM WorkItems would fill up and each
|
||
// WorkItem potentially holds on to a substantial amount of memory.
|
||
//
|
||
// So the actual goal is to always produce just enough LLVM WorkItems as
|
||
// not to starve our LLVM worker threads. That means, once we have enough
|
||
// WorkItems in our queue, we can block the main thread, so it does not
|
||
// produce more until we need them.
|
||
//
|
||
// Doing LLVM Work on the Main Thread
|
||
// ----------------------------------
|
||
// Since the main thread owns the compiler processes implicit `Token`, it is
|
||
// wasteful to keep it blocked without doing any work. Therefore, what we do
|
||
// in this case is: We spawn off an additional LLVM worker thread that helps
|
||
// reduce the queue. The work it is doing corresponds to the implicit
|
||
// `Token`. The coordinator will mark the main thread as being busy with
|
||
// LLVM work. (The actual work happens on another OS thread but we just care
|
||
// about `Tokens`, not actual threads).
|
||
//
|
||
// When any LLVM worker thread finishes while the main thread is marked as
|
||
// "busy with LLVM work", we can do a little switcheroo: We give the Token
|
||
// of the just finished thread to the LLVM worker thread that is working on
|
||
// behalf of the main thread's implicit Token, thus freeing up the main
|
||
// thread again. The coordinator can then again decide what the main thread
|
||
// should do. This allows the coordinator to make decisions at more points
|
||
// in time.
|
||
//
|
||
// Striking a Balance between Throughput and Memory Consumption
|
||
// ------------------------------------------------------------
|
||
// Since our two goals, (1) use as many Tokens as possible and (2) keep
|
||
// memory consumption as low as possible, are in conflict with each other,
|
||
// we have to find a trade off between them. Right now, the goal is to keep
|
||
// all workers busy, which means that no worker should find the queue empty
|
||
// when it is ready to start.
|
||
// How do we do achieve this? Good question :) We actually never know how
|
||
// many `Tokens` are potentially available so it's hard to say how much to
|
||
// fill up the queue before switching the main thread to LLVM work. Also we
|
||
// currently don't have a means to estimate how long a running LLVM worker
|
||
// will still be busy with it's current WorkItem. However, we know the
|
||
// maximal count of available Tokens that makes sense (=the number of CPU
|
||
// cores), so we can take a conservative guess. The heuristic we use here
|
||
// is implemented in the `queue_full_enough()` function.
|
||
//
|
||
// Some Background on Jobservers
|
||
// -----------------------------
|
||
// It's worth also touching on the management of parallelism here. We don't
|
||
// want to just spawn a thread per work item because while that's optimal
|
||
// parallelism it may overload a system with too many threads or violate our
|
||
// configuration for the maximum amount of cpu to use for this process. To
|
||
// manage this we use the `jobserver` crate.
|
||
//
|
||
// Job servers are an artifact of GNU make and are used to manage
|
||
// parallelism between processes. A jobserver is a glorified IPC semaphore
|
||
// basically. Whenever we want to run some work we acquire the semaphore,
|
||
// and whenever we're done with that work we release the semaphore. In this
|
||
// manner we can ensure that the maximum number of parallel workers is
|
||
// capped at any one point in time.
|
||
//
|
||
// LTO and the coordinator thread
|
||
// ------------------------------
|
||
//
|
||
// The final job the coordinator thread is responsible for is managing LTO
|
||
// and how that works. When LTO is requested what we'll to is collect all
|
||
// optimized LLVM modules into a local vector on the coordinator. Once all
|
||
// modules have been codegened and optimized we hand this to the `lto`
|
||
// module for further optimization. The `lto` module will return back a list
|
||
// of more modules to work on, which the coordinator will continue to spawn
|
||
// work for.
|
||
//
|
||
// Each LLVM module is automatically sent back to the coordinator for LTO if
|
||
// necessary. There's already optimizations in place to avoid sending work
|
||
// back to the coordinator if LTO isn't requested.
|
||
return thread::spawn(move || {
|
||
let mut worker_id_counter = 0;
|
||
let mut free_worker_ids = Vec::new();
|
||
let mut get_worker_id = |free_worker_ids: &mut Vec<usize>| {
|
||
if let Some(id) = free_worker_ids.pop() {
|
||
id
|
||
} else {
|
||
let id = worker_id_counter;
|
||
worker_id_counter += 1;
|
||
id
|
||
}
|
||
};
|
||
|
||
// This is where we collect codegen units that have gone all the way
|
||
// through codegen and LLVM.
|
||
let mut compiled_modules = vec![];
|
||
let mut compiled_metadata_module = None;
|
||
let mut compiled_allocator_module = None;
|
||
let mut needs_link = Vec::new();
|
||
let mut needs_fat_lto = Vec::new();
|
||
let mut needs_thin_lto = Vec::new();
|
||
let mut lto_import_only_modules = Vec::new();
|
||
let mut started_lto = false;
|
||
let mut codegen_aborted = false;
|
||
|
||
// This flag tracks whether all items have gone through codegens
|
||
let mut codegen_done = false;
|
||
|
||
// This is the queue of LLVM work items that still need processing.
|
||
let mut work_items = Vec::<(WorkItem<B>, u64)>::new();
|
||
|
||
// This are the Jobserver Tokens we currently hold. Does not include
|
||
// the implicit Token the compiler process owns no matter what.
|
||
let mut tokens = Vec::new();
|
||
|
||
let mut main_thread_worker_state = MainThreadWorkerState::Idle;
|
||
let mut running = 0;
|
||
|
||
let prof = &cgcx.prof;
|
||
let mut llvm_start_time: Option<VerboseTimingGuard<'_>> = None;
|
||
|
||
// Run the message loop while there's still anything that needs message
|
||
// processing. Note that as soon as codegen is aborted we simply want to
|
||
// wait for all existing work to finish, so many of the conditions here
|
||
// only apply if codegen hasn't been aborted as they represent pending
|
||
// work to be done.
|
||
while !codegen_done
|
||
|| running > 0
|
||
|| (!codegen_aborted
|
||
&& !(work_items.is_empty()
|
||
&& needs_fat_lto.is_empty()
|
||
&& needs_thin_lto.is_empty()
|
||
&& lto_import_only_modules.is_empty()
|
||
&& main_thread_worker_state == MainThreadWorkerState::Idle))
|
||
{
|
||
// While there are still CGUs to be codegened, the coordinator has
|
||
// to decide how to utilize the compiler processes implicit Token:
|
||
// For codegenning more CGU or for running them through LLVM.
|
||
if !codegen_done {
|
||
if main_thread_worker_state == MainThreadWorkerState::Idle {
|
||
// Compute the number of workers that will be running once we've taken as many
|
||
// items from the work queue as we can, plus one for the main thread. It's not
|
||
// critically important that we use this instead of just `running`, but it
|
||
// prevents the `queue_full_enough` heuristic from fluctuating just because a
|
||
// worker finished up and we decreased the `running` count, even though we're
|
||
// just going to increase it right after this when we put a new worker to work.
|
||
let extra_tokens = tokens.len().checked_sub(running).unwrap();
|
||
let additional_running = std::cmp::min(extra_tokens, work_items.len());
|
||
let anticipated_running = running + additional_running + 1;
|
||
|
||
if !queue_full_enough(work_items.len(), anticipated_running) {
|
||
// The queue is not full enough, codegen more items:
|
||
if codegen_worker_send.send(Message::CodegenItem).is_err() {
|
||
panic!("Could not send Message::CodegenItem to main thread")
|
||
}
|
||
main_thread_worker_state = MainThreadWorkerState::Codegenning;
|
||
} else {
|
||
// The queue is full enough to not let the worker
|
||
// threads starve. Use the implicit Token to do some
|
||
// LLVM work too.
|
||
let (item, _) =
|
||
work_items.pop().expect("queue empty - queue_full_enough() broken?");
|
||
let cgcx = CodegenContext {
|
||
worker: get_worker_id(&mut free_worker_ids),
|
||
..cgcx.clone()
|
||
};
|
||
maybe_start_llvm_timer(
|
||
prof,
|
||
cgcx.config(item.module_kind()),
|
||
&mut llvm_start_time,
|
||
);
|
||
main_thread_worker_state = MainThreadWorkerState::LLVMing;
|
||
spawn_work(cgcx, item);
|
||
}
|
||
}
|
||
} else if codegen_aborted {
|
||
// don't queue up any more work if codegen was aborted, we're
|
||
// just waiting for our existing children to finish
|
||
} else {
|
||
// If we've finished everything related to normal codegen
|
||
// then it must be the case that we've got some LTO work to do.
|
||
// Perform the serial work here of figuring out what we're
|
||
// going to LTO and then push a bunch of work items onto our
|
||
// queue to do LTO
|
||
if work_items.is_empty()
|
||
&& running == 0
|
||
&& main_thread_worker_state == MainThreadWorkerState::Idle
|
||
{
|
||
assert!(!started_lto);
|
||
started_lto = true;
|
||
|
||
let needs_fat_lto = mem::take(&mut needs_fat_lto);
|
||
let needs_thin_lto = mem::take(&mut needs_thin_lto);
|
||
let import_only_modules = mem::take(&mut lto_import_only_modules);
|
||
|
||
for (work, cost) in
|
||
generate_lto_work(&cgcx, needs_fat_lto, needs_thin_lto, import_only_modules)
|
||
{
|
||
let insertion_index = work_items
|
||
.binary_search_by_key(&cost, |&(_, cost)| cost)
|
||
.unwrap_or_else(|e| e);
|
||
work_items.insert(insertion_index, (work, cost));
|
||
if !cgcx.opts.debugging_opts.no_parallel_llvm {
|
||
helper.request_token();
|
||
}
|
||
}
|
||
}
|
||
|
||
// In this branch, we know that everything has been codegened,
|
||
// so it's just a matter of determining whether the implicit
|
||
// Token is free to use for LLVM work.
|
||
match main_thread_worker_state {
|
||
MainThreadWorkerState::Idle => {
|
||
if let Some((item, _)) = work_items.pop() {
|
||
let cgcx = CodegenContext {
|
||
worker: get_worker_id(&mut free_worker_ids),
|
||
..cgcx.clone()
|
||
};
|
||
maybe_start_llvm_timer(
|
||
prof,
|
||
cgcx.config(item.module_kind()),
|
||
&mut llvm_start_time,
|
||
);
|
||
main_thread_worker_state = MainThreadWorkerState::LLVMing;
|
||
spawn_work(cgcx, item);
|
||
} else {
|
||
// There is no unstarted work, so let the main thread
|
||
// take over for a running worker. Otherwise the
|
||
// implicit token would just go to waste.
|
||
// We reduce the `running` counter by one. The
|
||
// `tokens.truncate()` below will take care of
|
||
// giving the Token back.
|
||
debug_assert!(running > 0);
|
||
running -= 1;
|
||
main_thread_worker_state = MainThreadWorkerState::LLVMing;
|
||
}
|
||
}
|
||
MainThreadWorkerState::Codegenning => bug!(
|
||
"codegen worker should not be codegenning after \
|
||
codegen was already completed"
|
||
),
|
||
MainThreadWorkerState::LLVMing => {
|
||
// Already making good use of that token
|
||
}
|
||
}
|
||
}
|
||
|
||
// Spin up what work we can, only doing this while we've got available
|
||
// parallelism slots and work left to spawn.
|
||
while !codegen_aborted && !work_items.is_empty() && running < tokens.len() {
|
||
let (item, _) = work_items.pop().unwrap();
|
||
|
||
maybe_start_llvm_timer(prof, cgcx.config(item.module_kind()), &mut llvm_start_time);
|
||
|
||
let cgcx =
|
||
CodegenContext { worker: get_worker_id(&mut free_worker_ids), ..cgcx.clone() };
|
||
|
||
spawn_work(cgcx, item);
|
||
running += 1;
|
||
}
|
||
|
||
// Relinquish accidentally acquired extra tokens
|
||
tokens.truncate(running);
|
||
|
||
// If a thread exits successfully then we drop a token associated
|
||
// with that worker and update our `running` count. We may later
|
||
// re-acquire a token to continue running more work. We may also not
|
||
// actually drop a token here if the worker was running with an
|
||
// "ephemeral token"
|
||
let mut free_worker = |worker_id| {
|
||
if main_thread_worker_state == MainThreadWorkerState::LLVMing {
|
||
main_thread_worker_state = MainThreadWorkerState::Idle;
|
||
} else {
|
||
running -= 1;
|
||
}
|
||
|
||
free_worker_ids.push(worker_id);
|
||
};
|
||
|
||
let msg = coordinator_receive.recv().unwrap();
|
||
match *msg.downcast::<Message<B>>().ok().unwrap() {
|
||
// Save the token locally and the next turn of the loop will use
|
||
// this to spawn a new unit of work, or it may get dropped
|
||
// immediately if we have no more work to spawn.
|
||
Message::Token(token) => {
|
||
match token {
|
||
Ok(token) => {
|
||
tokens.push(token);
|
||
|
||
if main_thread_worker_state == MainThreadWorkerState::LLVMing {
|
||
// If the main thread token is used for LLVM work
|
||
// at the moment, we turn that thread into a regular
|
||
// LLVM worker thread, so the main thread is free
|
||
// to react to codegen demand.
|
||
main_thread_worker_state = MainThreadWorkerState::Idle;
|
||
running += 1;
|
||
}
|
||
}
|
||
Err(e) => {
|
||
let msg = &format!("failed to acquire jobserver token: {}", e);
|
||
shared_emitter.fatal(msg);
|
||
// Exit the coordinator thread
|
||
panic!("{}", msg)
|
||
}
|
||
}
|
||
}
|
||
|
||
Message::CodegenDone { llvm_work_item, cost } => {
|
||
// We keep the queue sorted by estimated processing cost,
|
||
// so that more expensive items are processed earlier. This
|
||
// is good for throughput as it gives the main thread more
|
||
// time to fill up the queue and it avoids scheduling
|
||
// expensive items to the end.
|
||
// Note, however, that this is not ideal for memory
|
||
// consumption, as LLVM module sizes are not evenly
|
||
// distributed.
|
||
let insertion_index = work_items.binary_search_by_key(&cost, |&(_, cost)| cost);
|
||
let insertion_index = match insertion_index {
|
||
Ok(idx) | Err(idx) => idx,
|
||
};
|
||
work_items.insert(insertion_index, (llvm_work_item, cost));
|
||
|
||
if !cgcx.opts.debugging_opts.no_parallel_llvm {
|
||
helper.request_token();
|
||
}
|
||
assert!(!codegen_aborted);
|
||
assert_eq!(main_thread_worker_state, MainThreadWorkerState::Codegenning);
|
||
main_thread_worker_state = MainThreadWorkerState::Idle;
|
||
}
|
||
|
||
Message::CodegenComplete => {
|
||
codegen_done = true;
|
||
assert!(!codegen_aborted);
|
||
assert_eq!(main_thread_worker_state, MainThreadWorkerState::Codegenning);
|
||
main_thread_worker_state = MainThreadWorkerState::Idle;
|
||
}
|
||
|
||
// If codegen is aborted that means translation was aborted due
|
||
// to some normal-ish compiler error. In this situation we want
|
||
// to exit as soon as possible, but we want to make sure all
|
||
// existing work has finished. Flag codegen as being done, and
|
||
// then conditions above will ensure no more work is spawned but
|
||
// we'll keep executing this loop until `running` hits 0.
|
||
Message::CodegenAborted => {
|
||
assert!(!codegen_aborted);
|
||
codegen_done = true;
|
||
codegen_aborted = true;
|
||
assert_eq!(main_thread_worker_state, MainThreadWorkerState::Codegenning);
|
||
}
|
||
Message::Done { result: Ok(compiled_module), worker_id } => {
|
||
free_worker(worker_id);
|
||
match compiled_module.kind {
|
||
ModuleKind::Regular => {
|
||
compiled_modules.push(compiled_module);
|
||
}
|
||
ModuleKind::Metadata => {
|
||
assert!(compiled_metadata_module.is_none());
|
||
compiled_metadata_module = Some(compiled_module);
|
||
}
|
||
ModuleKind::Allocator => {
|
||
assert!(compiled_allocator_module.is_none());
|
||
compiled_allocator_module = Some(compiled_module);
|
||
}
|
||
}
|
||
}
|
||
Message::NeedsLink { module, worker_id } => {
|
||
free_worker(worker_id);
|
||
needs_link.push(module);
|
||
}
|
||
Message::NeedsFatLTO { result, worker_id } => {
|
||
assert!(!started_lto);
|
||
free_worker(worker_id);
|
||
needs_fat_lto.push(result);
|
||
}
|
||
Message::NeedsThinLTO { name, thin_buffer, worker_id } => {
|
||
assert!(!started_lto);
|
||
free_worker(worker_id);
|
||
needs_thin_lto.push((name, thin_buffer));
|
||
}
|
||
Message::AddImportOnlyModule { module_data, work_product } => {
|
||
assert!(!started_lto);
|
||
assert!(!codegen_done);
|
||
assert_eq!(main_thread_worker_state, MainThreadWorkerState::Codegenning);
|
||
lto_import_only_modules.push((module_data, work_product));
|
||
main_thread_worker_state = MainThreadWorkerState::Idle;
|
||
}
|
||
// If the thread failed that means it panicked, so we abort immediately.
|
||
Message::Done { result: Err(None), worker_id: _ } => {
|
||
bug!("worker thread panicked");
|
||
}
|
||
Message::Done { result: Err(Some(WorkerFatalError)), worker_id: _ } => {
|
||
return Err(());
|
||
}
|
||
Message::CodegenItem => bug!("the coordinator should not receive codegen requests"),
|
||
}
|
||
}
|
||
|
||
let needs_link = mem::take(&mut needs_link);
|
||
if !needs_link.is_empty() {
|
||
assert!(compiled_modules.is_empty());
|
||
let diag_handler = cgcx.create_diag_handler();
|
||
let module = B::run_link(&cgcx, &diag_handler, needs_link).map_err(|_| ())?;
|
||
let module = unsafe {
|
||
B::codegen(&cgcx, &diag_handler, module, cgcx.config(ModuleKind::Regular))
|
||
.map_err(|_| ())?
|
||
};
|
||
compiled_modules.push(module);
|
||
}
|
||
|
||
// Drop to print timings
|
||
drop(llvm_start_time);
|
||
|
||
// Regardless of what order these modules completed in, report them to
|
||
// the backend in the same order every time to ensure that we're handing
|
||
// out deterministic results.
|
||
compiled_modules.sort_by(|a, b| a.name.cmp(&b.name));
|
||
|
||
Ok(CompiledModules {
|
||
modules: compiled_modules,
|
||
metadata_module: compiled_metadata_module,
|
||
allocator_module: compiled_allocator_module,
|
||
})
|
||
});
|
||
|
||
// A heuristic that determines if we have enough LLVM WorkItems in the
|
||
// queue so that the main thread can do LLVM work instead of codegen
|
||
fn queue_full_enough(items_in_queue: usize, workers_running: usize) -> bool {
|
||
// This heuristic scales ahead-of-time codegen according to available
|
||
// concurrency, as measured by `workers_running`. The idea is that the
|
||
// more concurrency we have available, the more demand there will be for
|
||
// work items, and the fuller the queue should be kept to meet demand.
|
||
// An important property of this approach is that we codegen ahead of
|
||
// time only as much as necessary, so as to keep fewer LLVM modules in
|
||
// memory at once, thereby reducing memory consumption.
|
||
//
|
||
// When the number of workers running is less than the max concurrency
|
||
// available to us, this heuristic can cause us to instruct the main
|
||
// thread to work on an LLVM item (that is, tell it to "LLVM") instead
|
||
// of codegen, even though it seems like it *should* be codegenning so
|
||
// that we can create more work items and spawn more LLVM workers.
|
||
//
|
||
// But this is not a problem. When the main thread is told to LLVM,
|
||
// according to this heuristic and how work is scheduled, there is
|
||
// always at least one item in the queue, and therefore at least one
|
||
// pending jobserver token request. If there *is* more concurrency
|
||
// available, we will immediately receive a token, which will upgrade
|
||
// the main thread's LLVM worker to a real one (conceptually), and free
|
||
// up the main thread to codegen if necessary. On the other hand, if
|
||
// there isn't more concurrency, then the main thread working on an LLVM
|
||
// item is appropriate, as long as the queue is full enough for demand.
|
||
//
|
||
// Speaking of which, how full should we keep the queue? Probably less
|
||
// full than you'd think. A lot has to go wrong for the queue not to be
|
||
// full enough and for that to have a negative effect on compile times.
|
||
//
|
||
// Workers are unlikely to finish at exactly the same time, so when one
|
||
// finishes and takes another work item off the queue, we often have
|
||
// ample time to codegen at that point before the next worker finishes.
|
||
// But suppose that codegen takes so long that the workers exhaust the
|
||
// queue, and we have one or more workers that have nothing to work on.
|
||
// Well, it might not be so bad. Of all the LLVM modules we create and
|
||
// optimize, one has to finish last. It's not necessarily the case that
|
||
// by losing some concurrency for a moment, we delay the point at which
|
||
// that last LLVM module is finished and the rest of compilation can
|
||
// proceed. Also, when we can't take advantage of some concurrency, we
|
||
// give tokens back to the job server. That enables some other rustc to
|
||
// potentially make use of the available concurrency. That could even
|
||
// *decrease* overall compile time if we're lucky. But yes, if no other
|
||
// rustc can make use of the concurrency, then we've squandered it.
|
||
//
|
||
// However, keeping the queue full is also beneficial when we have a
|
||
// surge in available concurrency. Then items can be taken from the
|
||
// queue immediately, without having to wait for codegen.
|
||
//
|
||
// So, the heuristic below tries to keep one item in the queue for every
|
||
// four running workers. Based on limited benchmarking, this appears to
|
||
// be more than sufficient to avoid increasing compilation times.
|
||
let quarter_of_workers = workers_running - 3 * workers_running / 4;
|
||
items_in_queue > 0 && items_in_queue >= quarter_of_workers
|
||
}
|
||
|
||
fn maybe_start_llvm_timer<'a>(
|
||
prof: &'a SelfProfilerRef,
|
||
config: &ModuleConfig,
|
||
llvm_start_time: &mut Option<VerboseTimingGuard<'a>>,
|
||
) {
|
||
if config.time_module && llvm_start_time.is_none() {
|
||
*llvm_start_time = Some(prof.extra_verbose_generic_activity("LLVM_passes", "crate"));
|
||
}
|
||
}
|
||
}
|
||
|
||
/// `FatalError` is explicitly not `Send`.
|
||
#[must_use]
|
||
pub struct WorkerFatalError;
|
||
|
||
fn spawn_work<B: ExtraBackendMethods>(cgcx: CodegenContext<B>, work: WorkItem<B>) {
|
||
let builder = thread::Builder::new().name(work.short_description());
|
||
builder
|
||
.spawn(move || {
|
||
// Set up a destructor which will fire off a message that we're done as
|
||
// we exit.
|
||
struct Bomb<B: ExtraBackendMethods> {
|
||
coordinator_send: Sender<Box<dyn Any + Send>>,
|
||
result: Option<Result<WorkItemResult<B>, FatalError>>,
|
||
worker_id: usize,
|
||
}
|
||
impl<B: ExtraBackendMethods> Drop for Bomb<B> {
|
||
fn drop(&mut self) {
|
||
let worker_id = self.worker_id;
|
||
let msg = match self.result.take() {
|
||
Some(Ok(WorkItemResult::Compiled(m))) => {
|
||
Message::Done::<B> { result: Ok(m), worker_id }
|
||
}
|
||
Some(Ok(WorkItemResult::NeedsLink(m))) => {
|
||
Message::NeedsLink::<B> { module: m, worker_id }
|
||
}
|
||
Some(Ok(WorkItemResult::NeedsFatLTO(m))) => {
|
||
Message::NeedsFatLTO::<B> { result: m, worker_id }
|
||
}
|
||
Some(Ok(WorkItemResult::NeedsThinLTO(name, thin_buffer))) => {
|
||
Message::NeedsThinLTO::<B> { name, thin_buffer, worker_id }
|
||
}
|
||
Some(Err(FatalError)) => {
|
||
Message::Done::<B> { result: Err(Some(WorkerFatalError)), worker_id }
|
||
}
|
||
None => Message::Done::<B> { result: Err(None), worker_id },
|
||
};
|
||
drop(self.coordinator_send.send(Box::new(msg)));
|
||
}
|
||
}
|
||
|
||
let mut bomb = Bomb::<B> {
|
||
coordinator_send: cgcx.coordinator_send.clone(),
|
||
result: None,
|
||
worker_id: cgcx.worker,
|
||
};
|
||
|
||
// Execute the work itself, and if it finishes successfully then flag
|
||
// ourselves as a success as well.
|
||
//
|
||
// Note that we ignore any `FatalError` coming out of `execute_work_item`,
|
||
// as a diagnostic was already sent off to the main thread - just
|
||
// surface that there was an error in this worker.
|
||
bomb.result = {
|
||
let _prof_timer = work.start_profiling(&cgcx);
|
||
Some(execute_work_item(&cgcx, work))
|
||
};
|
||
})
|
||
.expect("failed to spawn thread");
|
||
}
|
||
|
||
enum SharedEmitterMessage {
|
||
Diagnostic(Diagnostic),
|
||
InlineAsmError(u32, String, Level, Option<(String, Vec<InnerSpan>)>),
|
||
AbortIfErrors,
|
||
Fatal(String),
|
||
}
|
||
|
||
#[derive(Clone)]
|
||
pub struct SharedEmitter {
|
||
sender: Sender<SharedEmitterMessage>,
|
||
}
|
||
|
||
pub struct SharedEmitterMain {
|
||
receiver: Receiver<SharedEmitterMessage>,
|
||
}
|
||
|
||
impl SharedEmitter {
|
||
pub fn new() -> (SharedEmitter, SharedEmitterMain) {
|
||
let (sender, receiver) = channel();
|
||
|
||
(SharedEmitter { sender }, SharedEmitterMain { receiver })
|
||
}
|
||
|
||
pub fn inline_asm_error(
|
||
&self,
|
||
cookie: u32,
|
||
msg: String,
|
||
level: Level,
|
||
source: Option<(String, Vec<InnerSpan>)>,
|
||
) {
|
||
drop(self.sender.send(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)));
|
||
}
|
||
|
||
pub fn fatal(&self, msg: &str) {
|
||
drop(self.sender.send(SharedEmitterMessage::Fatal(msg.to_string())));
|
||
}
|
||
}
|
||
|
||
impl Emitter for SharedEmitter {
|
||
fn emit_diagnostic(&mut self, diag: &rustc_errors::Diagnostic) {
|
||
drop(self.sender.send(SharedEmitterMessage::Diagnostic(Diagnostic {
|
||
msg: diag.message(),
|
||
code: diag.code.clone(),
|
||
lvl: diag.level,
|
||
})));
|
||
for child in &diag.children {
|
||
drop(self.sender.send(SharedEmitterMessage::Diagnostic(Diagnostic {
|
||
msg: child.message(),
|
||
code: None,
|
||
lvl: child.level,
|
||
})));
|
||
}
|
||
drop(self.sender.send(SharedEmitterMessage::AbortIfErrors));
|
||
}
|
||
fn source_map(&self) -> Option<&Lrc<SourceMap>> {
|
||
None
|
||
}
|
||
}
|
||
|
||
impl SharedEmitterMain {
|
||
pub fn check(&self, sess: &Session, blocking: bool) {
|
||
loop {
|
||
let message = if blocking {
|
||
match self.receiver.recv() {
|
||
Ok(message) => Ok(message),
|
||
Err(_) => Err(()),
|
||
}
|
||
} else {
|
||
match self.receiver.try_recv() {
|
||
Ok(message) => Ok(message),
|
||
Err(_) => Err(()),
|
||
}
|
||
};
|
||
|
||
match message {
|
||
Ok(SharedEmitterMessage::Diagnostic(diag)) => {
|
||
let handler = sess.diagnostic();
|
||
let mut d = rustc_errors::Diagnostic::new(diag.lvl, &diag.msg);
|
||
if let Some(code) = diag.code {
|
||
d.code(code);
|
||
}
|
||
handler.emit_diagnostic(&d);
|
||
}
|
||
Ok(SharedEmitterMessage::InlineAsmError(cookie, msg, level, source)) => {
|
||
let msg = msg.strip_prefix("error: ").unwrap_or(&msg);
|
||
|
||
let mut err = match level {
|
||
Level::Error => sess.struct_err(&msg),
|
||
Level::Warning => sess.struct_warn(&msg),
|
||
Level::Note => sess.struct_note_without_error(&msg),
|
||
_ => bug!("Invalid inline asm diagnostic level"),
|
||
};
|
||
|
||
// If the cookie is 0 then we don't have span information.
|
||
if cookie != 0 {
|
||
let pos = BytePos::from_u32(cookie);
|
||
let span = Span::with_root_ctxt(pos, pos);
|
||
err.set_span(span);
|
||
};
|
||
|
||
// Point to the generated assembly if it is available.
|
||
if let Some((buffer, spans)) = source {
|
||
let source = sess
|
||
.source_map()
|
||
.new_source_file(FileName::inline_asm_source_code(&buffer), buffer);
|
||
let source_span = Span::with_root_ctxt(source.start_pos, source.end_pos);
|
||
let spans: Vec<_> =
|
||
spans.iter().map(|sp| source_span.from_inner(*sp)).collect();
|
||
err.span_note(spans, "instantiated into assembly here");
|
||
}
|
||
|
||
err.emit();
|
||
}
|
||
Ok(SharedEmitterMessage::AbortIfErrors) => {
|
||
sess.abort_if_errors();
|
||
}
|
||
Ok(SharedEmitterMessage::Fatal(msg)) => {
|
||
sess.fatal(&msg);
|
||
}
|
||
Err(_) => {
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
pub struct OngoingCodegen<B: ExtraBackendMethods> {
|
||
pub backend: B,
|
||
pub crate_name: Symbol,
|
||
pub metadata: EncodedMetadata,
|
||
pub windows_subsystem: Option<String>,
|
||
pub linker_info: LinkerInfo,
|
||
pub crate_info: CrateInfo,
|
||
pub coordinator_send: Sender<Box<dyn Any + Send>>,
|
||
pub codegen_worker_receive: Receiver<Message<B>>,
|
||
pub shared_emitter_main: SharedEmitterMain,
|
||
pub future: thread::JoinHandle<Result<CompiledModules, ()>>,
|
||
pub output_filenames: Arc<OutputFilenames>,
|
||
}
|
||
|
||
impl<B: ExtraBackendMethods> OngoingCodegen<B> {
|
||
pub fn join(self, sess: &Session) -> (CodegenResults, FxHashMap<WorkProductId, WorkProduct>) {
|
||
let _timer = sess.timer("finish_ongoing_codegen");
|
||
|
||
self.shared_emitter_main.check(sess, true);
|
||
let future = self.future;
|
||
let compiled_modules = sess.time("join_worker_thread", || match future.join() {
|
||
Ok(Ok(compiled_modules)) => compiled_modules,
|
||
Ok(Err(())) => {
|
||
sess.abort_if_errors();
|
||
panic!("expected abort due to worker thread errors")
|
||
}
|
||
Err(_) => {
|
||
bug!("panic during codegen/LLVM phase");
|
||
}
|
||
});
|
||
|
||
sess.cgu_reuse_tracker.check_expected_reuse(sess.diagnostic());
|
||
|
||
sess.abort_if_errors();
|
||
|
||
let work_products =
|
||
copy_all_cgu_workproducts_to_incr_comp_cache_dir(sess, &compiled_modules);
|
||
produce_final_output_artifacts(sess, &compiled_modules, &self.output_filenames);
|
||
|
||
// FIXME: time_llvm_passes support - does this use a global context or
|
||
// something?
|
||
if sess.codegen_units() == 1 && sess.time_llvm_passes() {
|
||
self.backend.print_pass_timings()
|
||
}
|
||
|
||
(
|
||
CodegenResults {
|
||
crate_name: self.crate_name,
|
||
metadata: self.metadata,
|
||
windows_subsystem: self.windows_subsystem,
|
||
linker_info: self.linker_info,
|
||
crate_info: self.crate_info,
|
||
|
||
modules: compiled_modules.modules,
|
||
allocator_module: compiled_modules.allocator_module,
|
||
metadata_module: compiled_modules.metadata_module,
|
||
},
|
||
work_products,
|
||
)
|
||
}
|
||
|
||
pub fn submit_pre_codegened_module_to_llvm(
|
||
&self,
|
||
tcx: TyCtxt<'_>,
|
||
module: ModuleCodegen<B::Module>,
|
||
) {
|
||
self.wait_for_signal_to_codegen_item();
|
||
self.check_for_errors(tcx.sess);
|
||
|
||
// These are generally cheap and won't throw off scheduling.
|
||
let cost = 0;
|
||
submit_codegened_module_to_llvm(&self.backend, &self.coordinator_send, module, cost);
|
||
}
|
||
|
||
pub fn codegen_finished(&self, tcx: TyCtxt<'_>) {
|
||
self.wait_for_signal_to_codegen_item();
|
||
self.check_for_errors(tcx.sess);
|
||
drop(self.coordinator_send.send(Box::new(Message::CodegenComplete::<B>)));
|
||
}
|
||
|
||
/// Consumes this context indicating that codegen was entirely aborted, and
|
||
/// we need to exit as quickly as possible.
|
||
///
|
||
/// This method blocks the current thread until all worker threads have
|
||
/// finished, and all worker threads should have exited or be real close to
|
||
/// exiting at this point.
|
||
pub fn codegen_aborted(self) {
|
||
// Signal to the coordinator it should spawn no more work and start
|
||
// shutdown.
|
||
drop(self.coordinator_send.send(Box::new(Message::CodegenAborted::<B>)));
|
||
drop(self.future.join());
|
||
}
|
||
|
||
pub fn check_for_errors(&self, sess: &Session) {
|
||
self.shared_emitter_main.check(sess, false);
|
||
}
|
||
|
||
pub fn wait_for_signal_to_codegen_item(&self) {
|
||
match self.codegen_worker_receive.recv() {
|
||
Ok(Message::CodegenItem) => {
|
||
// Nothing to do
|
||
}
|
||
Ok(_) => panic!("unexpected message"),
|
||
Err(_) => {
|
||
// One of the LLVM threads must have panicked, fall through so
|
||
// error handling can be reached.
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
pub fn submit_codegened_module_to_llvm<B: ExtraBackendMethods>(
|
||
_backend: &B,
|
||
tx_to_llvm_workers: &Sender<Box<dyn Any + Send>>,
|
||
module: ModuleCodegen<B::Module>,
|
||
cost: u64,
|
||
) {
|
||
let llvm_work_item = WorkItem::Optimize(module);
|
||
drop(tx_to_llvm_workers.send(Box::new(Message::CodegenDone::<B> { llvm_work_item, cost })));
|
||
}
|
||
|
||
pub fn submit_post_lto_module_to_llvm<B: ExtraBackendMethods>(
|
||
_backend: &B,
|
||
tx_to_llvm_workers: &Sender<Box<dyn Any + Send>>,
|
||
module: CachedModuleCodegen,
|
||
) {
|
||
let llvm_work_item = WorkItem::CopyPostLtoArtifacts(module);
|
||
drop(tx_to_llvm_workers.send(Box::new(Message::CodegenDone::<B> { llvm_work_item, cost: 0 })));
|
||
}
|
||
|
||
pub fn submit_pre_lto_module_to_llvm<B: ExtraBackendMethods>(
|
||
_backend: &B,
|
||
tcx: TyCtxt<'_>,
|
||
tx_to_llvm_workers: &Sender<Box<dyn Any + Send>>,
|
||
module: CachedModuleCodegen,
|
||
) {
|
||
let filename = pre_lto_bitcode_filename(&module.name);
|
||
let bc_path = in_incr_comp_dir_sess(tcx.sess, &filename);
|
||
let file = fs::File::open(&bc_path)
|
||
.unwrap_or_else(|e| panic!("failed to open bitcode file `{}`: {}", bc_path.display(), e));
|
||
|
||
let mmap = unsafe {
|
||
memmap2::Mmap::map(&file).unwrap_or_else(|e| {
|
||
panic!("failed to mmap bitcode file `{}`: {}", bc_path.display(), e)
|
||
})
|
||
};
|
||
// Schedule the module to be loaded
|
||
drop(tx_to_llvm_workers.send(Box::new(Message::AddImportOnlyModule::<B> {
|
||
module_data: SerializedModule::FromUncompressedFile(mmap),
|
||
work_product: module.source,
|
||
})));
|
||
}
|
||
|
||
pub fn pre_lto_bitcode_filename(module_name: &str) -> String {
|
||
format!("{}.{}", module_name, PRE_LTO_BC_EXT)
|
||
}
|
||
|
||
fn msvc_imps_needed(tcx: TyCtxt<'_>) -> bool {
|
||
// This should never be true (because it's not supported). If it is true,
|
||
// something is wrong with commandline arg validation.
|
||
assert!(
|
||
!(tcx.sess.opts.cg.linker_plugin_lto.enabled()
|
||
&& tcx.sess.target.is_like_windows
|
||
&& tcx.sess.opts.cg.prefer_dynamic)
|
||
);
|
||
|
||
tcx.sess.target.is_like_windows &&
|
||
tcx.sess.crate_types().iter().any(|ct| *ct == CrateType::Rlib) &&
|
||
// ThinLTO can't handle this workaround in all cases, so we don't
|
||
// emit the `__imp_` symbols. Instead we make them unnecessary by disallowing
|
||
// dynamic linking when linker plugin LTO is enabled.
|
||
!tcx.sess.opts.cg.linker_plugin_lto.enabled()
|
||
}
|