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Auto merge of rust-lang#115964 - bjorn3:cgu_reuse_tracker_global_stat…
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…e, r=cjgillot

Remove cgu_reuse_tracker from Session

This removes a bit of global mutable state.

It will now miss post-lto cgu reuse when ThinLTO determines that a cgu doesn't get changed, but there weren't any tests for this anyway and a test for it would be fragile to the exact implementation of ThinLTO in LLVM.
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@bors
bors committed Oct 13, 2023
2 parents e20cb77 + f0b5820 commit 130ff8c
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Showing 19 changed files with 274 additions and 322 deletions.
1 change: 1 addition & 0 deletions Cargo.lock
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Original file line number Diff line number Diff line change
Expand Up @@ -3650,6 +3650,7 @@ dependencies = [
"serde_json",
"smallvec",
"tempfile",
"thin-vec",
"thorin-dwp",
"tracing",
"windows",
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98 changes: 37 additions & 61 deletions compiler/rustc_codegen_cranelift/src/driver/aot.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,14 +7,15 @@ use std::sync::Arc;
use std::thread::JoinHandle;

use cranelift_object::{ObjectBuilder, ObjectModule};
use rustc_codegen_ssa::assert_module_sources::CguReuse;
use rustc_codegen_ssa::back::metadata::create_compressed_metadata_file;
use rustc_codegen_ssa::base::determine_cgu_reuse;
use rustc_codegen_ssa::{CodegenResults, CompiledModule, CrateInfo, ModuleKind};
use rustc_data_structures::profiling::SelfProfilerRef;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_metadata::EncodedMetadata;
use rustc_middle::dep_graph::{WorkProduct, WorkProductId};
use rustc_middle::mir::mono::{CodegenUnit, MonoItem};
use rustc_session::cgu_reuse_tracker::CguReuse;
use rustc_session::config::{DebugInfo, OutputFilenames, OutputType};
use rustc_session::Session;

Expand Down Expand Up @@ -374,43 +375,47 @@ pub(crate) fn run_aot(
}
}

// Calculate the CGU reuse
let cgu_reuse = tcx.sess.time("find_cgu_reuse", || {
cgus.iter().map(|cgu| determine_cgu_reuse(tcx, &cgu)).collect::<Vec<_>>()
});

rustc_codegen_ssa::assert_module_sources::assert_module_sources(tcx, &|cgu_reuse_tracker| {
for (i, cgu) in cgus.iter().enumerate() {
let cgu_reuse = cgu_reuse[i];
cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);
}
});

let global_asm_config = Arc::new(crate::global_asm::GlobalAsmConfig::new(tcx));

let mut concurrency_limiter = ConcurrencyLimiter::new(tcx.sess, cgus.len());

let modules = tcx.sess.time("codegen mono items", || {
cgus.iter()
.map(|cgu| {
let cgu_reuse = if backend_config.disable_incr_cache {
CguReuse::No
} else {
determine_cgu_reuse(tcx, cgu)
};
tcx.sess.cgu_reuse_tracker.set_actual_reuse(cgu.name().as_str(), cgu_reuse);

match cgu_reuse {
CguReuse::No => {
let dep_node = cgu.codegen_dep_node(tcx);
tcx.dep_graph
.with_task(
dep_node,
tcx,
(
backend_config.clone(),
global_asm_config.clone(),
cgu.name(),
concurrency_limiter.acquire(tcx.sess.diagnostic()),
),
module_codegen,
Some(rustc_middle::dep_graph::hash_result),
)
.0
}
CguReuse::PreLto => unreachable!(),
CguReuse::PostLto => {
concurrency_limiter.job_already_done();
OngoingModuleCodegen::Sync(reuse_workproduct_for_cgu(tcx, cgu))
}
.enumerate()
.map(|(i, cgu)| match cgu_reuse[i] {
CguReuse::No => {
let dep_node = cgu.codegen_dep_node(tcx);
tcx.dep_graph
.with_task(
dep_node,
tcx,
(
backend_config.clone(),
global_asm_config.clone(),
cgu.name(),
concurrency_limiter.acquire(tcx.sess.diagnostic()),
),
module_codegen,
Some(rustc_middle::dep_graph::hash_result),
)
.0
}
CguReuse::PreLto => unreachable!("LTO not yet supported"),
CguReuse::PostLto => {
concurrency_limiter.job_already_done();
OngoingModuleCodegen::Sync(reuse_workproduct_for_cgu(tcx, cgu))
}
})
.collect::<Vec<_>>()
Expand Down Expand Up @@ -489,32 +494,3 @@ pub(crate) fn run_aot(
concurrency_limiter,
})
}

// Adapted from https://github.com/rust-lang/rust/blob/303d8aff6092709edd4dbd35b1c88e9aa40bf6d8/src/librustc_codegen_ssa/base.rs#L922-L953
fn determine_cgu_reuse<'tcx>(tcx: TyCtxt<'tcx>, cgu: &CodegenUnit<'tcx>) -> CguReuse {
if !tcx.dep_graph.is_fully_enabled() {
return CguReuse::No;
}

let work_product_id = &cgu.work_product_id();
if tcx.dep_graph.previous_work_product(work_product_id).is_none() {
// We don't have anything cached for this CGU. This can happen
// if the CGU did not exist in the previous session.
return CguReuse::No;
}

// Try to mark the CGU as green. If it we can do so, it means that nothing
// affecting the LLVM module has changed and we can re-use a cached version.
// If we compile with any kind of LTO, this means we can re-use the bitcode
// of the Pre-LTO stage (possibly also the Post-LTO version but we'll only
// know that later). If we are not doing LTO, there is only one optimized
// version of each module, so we re-use that.
let dep_node = cgu.codegen_dep_node(tcx);
assert!(
!tcx.dep_graph.dep_node_exists(&dep_node),
"CompileCodegenUnit dep-node for CGU `{}` already exists before marking.",
cgu.name()
);

if tcx.try_mark_green(&dep_node) { CguReuse::PostLto } else { CguReuse::No }
}
2 changes: 0 additions & 2 deletions compiler/rustc_codegen_llvm/src/back/lto.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,6 @@ use rustc_hir::def_id::LOCAL_CRATE;
use rustc_middle::bug;
use rustc_middle::dep_graph::WorkProduct;
use rustc_middle::middle::exported_symbols::{SymbolExportInfo, SymbolExportLevel};
use rustc_session::cgu_reuse_tracker::CguReuse;
use rustc_session::config::{self, CrateType, Lto};

use std::ffi::{CStr, CString};
Expand Down Expand Up @@ -584,7 +583,6 @@ fn thin_lto(
copy_jobs.push(work_product);
info!(" - {}: re-used", module_name);
assert!(cgcx.incr_comp_session_dir.is_some());
cgcx.cgu_reuse_tracker.set_actual_reuse(module_name, CguReuse::PostLto);
continue;
}
}
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1 change: 1 addition & 0 deletions compiler/rustc_codegen_ssa/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ pathdiff = "0.2.0"
serde_json = "1.0.59"
smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
regex = "1.4"
thin-vec = "0.2.12"

rustc_serialize = { path = "../rustc_serialize" }
rustc_arena = { path = "../rustc_arena" }
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24 changes: 24 additions & 0 deletions compiler/rustc_codegen_ssa/messages.ftl
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Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,9 @@ codegen_ssa_atomic_compare_exchange = Atomic compare-exchange intrinsic missing
codegen_ssa_binary_output_to_tty = option `-o` or `--emit` is used to write binary output type `{$shorthand}` to stdout, but stdout is a tty
codegen_ssa_cgu_not_recorded =
CGU-reuse for `{$cgu_user_name}` is (mangled: `{$cgu_name}`) was not recorded
codegen_ssa_check_installed_visual_studio = please ensure that Visual Studio 2017 or later, or Build Tools for Visual Studio were installed with the Visual C++ option.
codegen_ssa_copy_path = could not copy {$from} to {$to}: {$error}
Expand Down Expand Up @@ -39,13 +42,21 @@ codegen_ssa_failed_to_get_layout = failed to get layout for {$ty}: {$err}
codegen_ssa_failed_to_write = failed to write {$path}: {$error}
codegen_ssa_field_associated_value_expected = associated value expected for `{$name}`
codegen_ssa_ignoring_emit_path = ignoring emit path because multiple .{$extension} files were produced
codegen_ssa_ignoring_output = ignoring -o because multiple .{$extension} files were produced
codegen_ssa_illegal_link_ordinal_format = illegal ordinal format in `link_ordinal`
.note = an unsuffixed integer value, e.g., `1`, is expected
codegen_ssa_incorrect_cgu_reuse_type =
CGU-reuse for `{$cgu_user_name}` is `{$actual_reuse}` but should be {$at_least ->
[one] {"at least "}
*[other] {""}
}`{$expected_reuse}`
codegen_ssa_insufficient_vs_code_product = VS Code is a different product, and is not sufficient.
codegen_ssa_invalid_link_ordinal_nargs = incorrect number of arguments to `#[link_ordinal]`
Expand Down Expand Up @@ -153,19 +164,30 @@ codegen_ssa_linker_unsupported_modifier = `as-needed` modifier not supported for
codegen_ssa_linking_failed = linking with `{$linker_path}` failed: {$exit_status}
codegen_ssa_malformed_cgu_name =
found malformed codegen unit name `{$user_path}`. codegen units names must always start with the name of the crate (`{$crate_name}` in this case).
codegen_ssa_metadata_object_file_write = error writing metadata object file: {$error}
codegen_ssa_missing_cpp_build_tool_component = or a necessary component may be missing from the "C++ build tools" workload
codegen_ssa_missing_memory_ordering = Atomic intrinsic missing memory ordering
codegen_ssa_missing_query_depgraph =
found CGU-reuse attribute but `-Zquery-dep-graph` was not specified
codegen_ssa_msvc_missing_linker = the msvc targets depend on the msvc linker but `link.exe` was not found
codegen_ssa_multiple_external_func_decl = multiple declarations of external function `{$function}` from library `{$library_name}` have different calling conventions
codegen_ssa_multiple_main_functions = entry symbol `main` declared multiple times
.help = did you use `#[no_mangle]` on `fn main`? Use `#[start]` instead
codegen_ssa_no_field = no field `{$name}`
codegen_ssa_no_module_named =
no module named `{$user_path}` (mangled: {$cgu_name}). available modules: {$cgu_names}
codegen_ssa_no_natvis_directory = error enumerating natvis directory: {$error}
codegen_ssa_processing_dymutil_failed = processing debug info with `dsymutil` failed: {$status}
Expand Down Expand Up @@ -297,6 +319,8 @@ codegen_ssa_unknown_atomic_operation = unknown atomic operation
codegen_ssa_unknown_atomic_ordering = unknown ordering in atomic intrinsic
codegen_ssa_unknown_reuse_kind = unknown cgu-reuse-kind `{$kind}` specified
codegen_ssa_unsupported_arch = unsupported arch `{$arch}` for os `{$os}`
codegen_ssa_unsupported_link_self_contained = option `-C link-self-contained` is not supported on this target
Expand Down
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