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Allow targets to override default codegen backend

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This commit is contained in:
Maybe Waffle 2024-02-14 23:43:00 +00:00
parent ee9c7c940c
commit a03d19ef63
7 changed files with 130 additions and 46 deletions
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19
compiler/rustc_driver_impl/src/lib.rs
View File

@ -35,7 +35,7 @@
use rustc_session::config::{ErrorOutputType, Input, OutFileName, OutputType};
use rustc_session::getopts::{self, Matches};
use rustc_session::lint::{Lint, LintId};
use rustc_session::{config, EarlyDiagCtxt, Session};
use rustc_session::{config, filesearch, EarlyDiagCtxt, Session};
use rustc_span::def_id::LOCAL_CRATE;
use rustc_span::source_map::FileLoader;
use rustc_span::symbol::sym;
@ -887,7 +887,13 @@ pub fn version_at_macro_invocation(
let debug_flags = matches.opt_strs("Z");
let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
get_codegen_backend(early_dcx, &None, backend_name).print_version();
let opts = config::Options::default();
let sysroot = opts.maybe_sysroot.clone().unwrap_or_else(|| {
filesearch::get_or_default_sysroot().expect("Failed finding sysroot")
});
let target = config::build_target_config(early_dcx, &opts, None, &sysroot);
get_codegen_backend(early_dcx, &sysroot, backend_name, &target).print_version();
}
}
@ -1092,7 +1098,14 @@ pub fn describe_flag_categories(early_dcx: &EarlyDiagCtxt, matches: &Matches) ->
if cg_flags.iter().any(|x| *x == "passes=list") {
let backend_name = debug_flags.iter().find_map(|x| x.strip_prefix("codegen-backend="));
get_codegen_backend(early_dcx, &None, backend_name).print_passes();
let opts = config::Options::default();
let sysroot = opts.maybe_sysroot.clone().unwrap_or_else(|| {
filesearch::get_or_default_sysroot().expect("Failed finding sysroot")
});
let target = config::build_target_config(early_dcx, &opts, None, &sysroot);
get_codegen_backend(early_dcx, &sysroot, backend_name, &target).print_passes();
return true;
}

72
compiler/rustc_interface/src/interface.rs
View File

@ -16,7 +16,7 @@
use rustc_query_impl::QueryCtxt;
use rustc_query_system::query::print_query_stack;
use rustc_session::config::{self, Cfg, CheckCfg, ExpectedValues, Input, OutFileName};
use rustc_session::filesearch::sysroot_candidates;
use rustc_session::filesearch::{self, sysroot_candidates};
use rustc_session::parse::ParseSess;
use rustc_session::{lint, CompilerIO, EarlyDiagCtxt, Session};
use rustc_span::source_map::FileLoader;
@ -336,14 +336,66 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
let early_dcx = EarlyDiagCtxt::new(config.opts.error_format);
let codegen_backend = if let Some(make_codegen_backend) = config.make_codegen_backend {
make_codegen_backend(&config.opts)
} else {
util::get_codegen_backend(
let sysroot = match &config.opts.maybe_sysroot {
Some(sysroot) => sysroot.clone(),
None => filesearch::get_or_default_sysroot().expect("Failed finding sysroot"),
};
let (codegen_backend, target_cfg) = match config.make_codegen_backend {
None => {
// Build a target without override, so that it can override the backend if needed
let target =
config::build_target_config(&early_dcx, &config.opts, None, &sysroot);
let backend = util::get_codegen_backend(
&early_dcx,
&config.opts.maybe_sysroot,
&sysroot,
config.opts.unstable_opts.codegen_backend.as_deref(),
)
&target,
);
// target_override is documented to be called before init(), so this is okay
let target_override = backend.target_override(&config.opts);
// Assert that we don't use target's override of the backend and
// backend's override of the target at the same time
if config.opts.unstable_opts.codegen_backend.is_none()
&& target.default_codegen_backend.is_some()
&& target_override.is_some()
{
rustc_middle::bug!(
"Codegen backend requested target override even though the target requested the backend"
);
}
// Re-build target with the (potential) override
let target = config::build_target_config(
&early_dcx,
&config.opts,
target_override,
&sysroot,
);
(backend, target)
}
Some(make_codegen_backend) => {
// N.B. `make_codegen_backend` takes precedence over `target.default_codegen_backend`,
// which is ignored in this case.
let backend = make_codegen_backend(&config.opts);
// target_override is documented to be called before init(), so this is okay
let target_override = backend.target_override(&config.opts);
let target = config::build_target_config(
&early_dcx,
&config.opts,
target_override,
&sysroot,
);
(backend, target)
}
};
let temps_dir = config.opts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
@ -364,9 +416,6 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
let mut locale_resources = Vec::from(config.locale_resources);
locale_resources.push(codegen_backend.locale_resource());
// target_override is documented to be called before init(), so this is okay
let target_override = codegen_backend.target_override(&config.opts);
let mut sess = rustc_session::build_session(
early_dcx,
config.opts,
@ -381,7 +430,8 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
locale_resources,
config.lint_caps,
config.file_loader,
target_override,
target_cfg,
sysroot,
util::rustc_version_str().unwrap_or("unknown"),
config.ice_file,
config.using_internal_features,

14
compiler/rustc_interface/src/tests.rs
View File

@ -37,6 +37,17 @@ fn mk_session(matches: getopts::Matches) -> (Session, Cfg) {
output_file: None,
temps_dir,
};
let sysroot = match &sessopts.maybe_sysroot {
Some(sysroot) => sysroot.clone(),
None => {
rustc_session::filesearch::get_or_default_sysroot().expect("Failed finding sysroot")
}
};
let target_cfg =
rustc_session::config::build_target_config(&early_dcx, &sessopts, None, &sysroot);
let sess = build_session(
early_dcx,
sessopts,
@ -46,7 +57,8 @@ fn mk_session(matches: getopts::Matches) -> (Session, Cfg) {
vec![],
Default::default(),
None,
None,
target_cfg,
sysroot,
"",
None,
Arc::default(),

27
compiler/rustc_interface/src/util.rs
View File

@ -14,14 +14,15 @@
use rustc_span::edit_distance::find_best_match_for_name;
use rustc_span::edition::Edition;
use rustc_span::symbol::{sym, Symbol};
use rustc_target::spec::Target;
use session::EarlyDiagCtxt;
use std::env;
use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
use std::mem;
use std::path::{Path, PathBuf};
use std::sync::atomic::{AtomicBool, Ordering};
use std::sync::OnceLock;
use std::thread;
use std::{env, iter};
/// Function pointer type that constructs a new CodegenBackend.
pub type MakeBackendFn = fn() -> Box<dyn CodegenBackend>;
@ -192,21 +193,25 @@ fn format_err(e: &(dyn std::error::Error + 'static)) -> String {
/// A name of `None` indicates that the default backend should be used.
pub fn get_codegen_backend(
early_dcx: &EarlyDiagCtxt,
maybe_sysroot: &Option<PathBuf>,
sysroot: &Path,
backend_name: Option<&str>,
target: &Target,
) -> Box<dyn CodegenBackend> {
static LOAD: OnceLock<unsafe fn() -> Box<dyn CodegenBackend>> = OnceLock::new();
let load = LOAD.get_or_init(|| {
let default_codegen_backend = option_env!("CFG_DEFAULT_CODEGEN_BACKEND").unwrap_or("llvm");
let backend = backend_name
.or(target.default_codegen_backend.as_deref())
.or(option_env!("CFG_DEFAULT_CODEGEN_BACKEND"))
.unwrap_or("llvm");
match backend_name.unwrap_or(default_codegen_backend) {
match backend {
filename if filename.contains('.') => {
load_backend_from_dylib(early_dcx, filename.as_ref())
}
#[cfg(feature = "llvm")]
"llvm" => rustc_codegen_llvm::LlvmCodegenBackend::new,
backend_name => get_codegen_sysroot(early_dcx, maybe_sysroot, backend_name),
backend_name => get_codegen_sysroot(early_dcx, sysroot, backend_name),
}
});
@ -240,7 +245,7 @@ fn get_rustc_path_inner(bin_path: &str) -> Option<PathBuf> {
fn get_codegen_sysroot(
early_dcx: &EarlyDiagCtxt,
maybe_sysroot: &Option<PathBuf>,
sysroot: &Path,
backend_name: &str,
) -> MakeBackendFn {
// For now we only allow this function to be called once as it'll dlopen a
@ -257,17 +262,16 @@ fn get_codegen_sysroot(
let target = session::config::host_triple();
let sysroot_candidates = sysroot_candidates();
let sysroot = maybe_sysroot
.iter()
.chain(sysroot_candidates.iter())
let sysroot = iter::once(sysroot)
.chain(sysroot_candidates.iter().map(<_>::as_ref))
.map(|sysroot| {
filesearch::make_target_lib_path(sysroot, target).with_file_name("codegen-backends")
})
.find(|f| {
info!("codegen backend candidate: {}", f.display());
f.exists()
});
let sysroot = sysroot.unwrap_or_else(|| {
})
.unwrap_or_else(|| {
let candidates = sysroot_candidates
.iter()
.map(|p| p.display().to_string())
@ -279,6 +283,7 @@ fn get_codegen_sysroot(
);
early_dcx.early_fatal(err);
});
info!("probing {} for a codegen backend", sysroot.display());
let d = sysroot.read_dir().unwrap_or_else(|e| {

2
compiler/rustc_session/src/config.rs
View File

@ -1558,7 +1558,7 @@ pub fn build_configuration(sess: &Session, mut user_cfg: Cfg) -> Cfg {
user_cfg
}
pub(super) fn build_target_config(
pub fn build_target_config(
early_dcx: &EarlyDiagCtxt,
opts: &Options,
target_override: Option<Target>,

9
compiler/rustc_session/src/session.rs
View File

@ -1034,7 +1034,8 @@ pub fn build_session(
fluent_resources: Vec<&'static str>,
driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
target_override: Option<Target>,
target_cfg: Target,
sysroot: PathBuf,
cfg_version: &'static str,
ice_file: Option<PathBuf>,
using_internal_features: Arc<AtomicBool>,
@ -1051,12 +1052,6 @@ pub fn build_session(
let cap_lints_allow = sopts.lint_cap.is_some_and(|cap| cap == lint::Allow);
let can_emit_warnings = !(warnings_allow || cap_lints_allow);
let sysroot = match &sopts.maybe_sysroot {
Some(sysroot) => sysroot.clone(),
None => filesearch::get_or_default_sysroot().expect("Failed finding sysroot"),
};
let target_cfg = config::build_target_config(&early_dcx, &sopts, target_override, &sysroot);
let host_triple = TargetTriple::from_triple(config::host_triple());
let (host, target_warnings) = Target::search(&host_triple, &sysroot).unwrap_or_else(|e| {
early_dcx.early_fatal(format!("Error loading host specification: {e}"))

9
compiler/rustc_target/src/spec/mod.rs
View File

@ -2044,6 +2044,14 @@ pub struct TargetOptions {
/// Default number of codegen units to use in debug mode
pub default_codegen_units: Option<u64>,
/// Default codegen backend used for this target. Defaults to `None`.
///
/// If `None`, then `CFG_DEFAULT_CODEGEN_BACKEND` environmental variable captured when
/// compiling `rustc` will be used instead (or llvm if it is not set).
///
/// N.B. when *using* the compiler, backend can always be overriden with `-Zcodegen-backend`.
pub default_codegen_backend: Option<StaticCow<str>>,
/// Whether to generate trap instructions in places where optimization would
/// otherwise produce control flow that falls through into unrelated memory.
pub trap_unreachable: bool,
@ -2350,6 +2358,7 @@ fn default() -> TargetOptions {
stack_probes: StackProbeType::None,
min_global_align: None,
default_codegen_units: None,
default_codegen_backend: None,
trap_unreachable: true,
requires_lto: false,
singlethread: false,