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Auto merge of #122993 - RalfJung:default-sysroot, r=<try>
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give rustc_driver users a chance to overwrite the default sysroot

and then use that in Miri.

This lets us get rid of an annoying arg-patching hack, and may help with rust-lang/miri#3404.

Unfortunately the computation of `real_rust_source_base_dir` depended on knowing the default sysroot, so I had to move that around a bit. I have no idea how all this `Session` and `Options` stuff works  so I hope this makes sense.
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@bors
bors committed Mar 25, 2024
2 parents fa374a8 + dedcc8b commit 92652ed
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Showing 6 changed files with 75 additions and 73 deletions.
4 changes: 0 additions & 4 deletions compiler/rustc_interface/src/tests.rs
View file
Expand Up @@ -642,10 +642,6 @@ fn test_top_level_options_tracked_no_crate() {

// Make sure that changing a [TRACKED_NO_CRATE_HASH] option leaves the crate hash unchanged but changes the incremental hash.
// tidy-alphabetical-start
tracked!(
real_rust_source_base_dir,
Some("/home/bors/rust/.rustup/toolchains/nightly/lib/rustlib/src/rust".into())
);
tracked!(remap_path_prefix, vec![("/home/bors/rust".into(), "src".into())]);
// tidy-alphabetical-end
}
Expand Down
29 changes: 21 additions & 8 deletions compiler/rustc_metadata/src/rmeta/decoder.rs
View file
Expand Up @@ -30,7 +30,7 @@ use rustc_span::{BytePos, Pos, SpanData, SpanDecoder, SyntaxContext, DUMMY_SP};

use proc_macro::bridge::client::ProcMacro;
use std::iter::TrustedLen;
use std::path::Path;
use std::path::{Path, PathBuf};
use std::{io, iter, mem};

pub(super) use cstore_impl::provide;
Expand Down Expand Up @@ -1589,10 +1589,14 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
/// Proc macro crates don't currently export spans, so this function does not have
/// to work for them.
fn imported_source_file(self, source_file_index: u32, sess: &Session) -> ImportedSourceFile {
fn filter<'a>(sess: &Session, path: Option<&'a Path>) -> Option<&'a Path> {
fn filter<'a>(
sess: &Session,
real_rust_source_base_dir: &Option<PathBuf>,
path: Option<&'a Path>,
) -> Option<&'a Path> {
path.filter(|_| {
// Only spend time on further checks if we have what to translate *to*.
sess.opts.real_rust_source_base_dir.is_some()
real_rust_source_base_dir.is_some()
// Some tests need the translation to be always skipped.
&& sess.opts.unstable_opts.translate_remapped_path_to_local_path
})
Expand All @@ -1604,25 +1608,34 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
})
}

let real_rust_source_base_dir = sess.real_rust_source_base_dir();
let try_to_translate_virtual_to_real = |name: &mut rustc_span::FileName| {
// Translate the virtual `/rustc/$hash` prefix back to a real directory
// that should hold actual sources, where possible.
//
// NOTE: if you update this, you might need to also update bootstrap's code for generating
// the `rust-src` component in `Src::run` in `src/bootstrap/dist.rs`.
let virtual_rust_source_base_dir = [
filter(sess, option_env!("CFG_VIRTUAL_RUST_SOURCE_BASE_DIR").map(Path::new)),
filter(sess, sess.opts.unstable_opts.simulate_remapped_rust_src_base.as_deref()),
filter(
sess,
&real_rust_source_base_dir,
option_env!("CFG_VIRTUAL_RUST_SOURCE_BASE_DIR").map(Path::new),
),
filter(
sess,
&real_rust_source_base_dir,
sess.opts.unstable_opts.simulate_remapped_rust_src_base.as_deref(),
),
];

debug!(
"try_to_translate_virtual_to_real(name={:?}): \
virtual_rust_source_base_dir={:?}, real_rust_source_base_dir={:?}",
name, virtual_rust_source_base_dir, sess.opts.real_rust_source_base_dir,
name, virtual_rust_source_base_dir, real_rust_source_base_dir,
);

for virtual_dir in virtual_rust_source_base_dir.iter().flatten() {
if let Some(real_dir) = &sess.opts.real_rust_source_base_dir {
if let Some(real_dir) = &real_rust_source_base_dir {
if let rustc_span::FileName::Real(old_name) = name {
if let rustc_span::RealFileName::Remapped { local_path: _, virtual_name } =
old_name
Expand Down Expand Up @@ -1713,7 +1726,7 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
// `try_to_translate_virtual_to_real` don't have to worry about how the
// compiler is bootstrapped.
if let Some(virtual_dir) = &sess.opts.unstable_opts.simulate_remapped_rust_src_base
&& let Some(real_dir) = &sess.opts.real_rust_source_base_dir
&& let Some(real_dir) = &real_rust_source_base_dir
&& let rustc_span::FileName::Real(ref mut old_name) = name
{
let relative_path = match old_name {
Expand Down
28 changes: 3 additions & 25 deletions compiler/rustc_session/src/config.rs
View file
Expand Up @@ -8,7 +8,7 @@ pub use crate::options::*;
use crate::errors::FileWriteFail;
use crate::search_paths::SearchPath;
use crate::utils::{CanonicalizedPath, NativeLib, NativeLibKind};
use crate::{filesearch, lint, HashStableContext};
use crate::{lint, HashStableContext};
use crate::{EarlyDiagCtxt, Session};
use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
use rustc_data_structures::stable_hasher::{StableOrd, ToStableHashKey};
Expand Down Expand Up @@ -1066,7 +1066,6 @@ impl Default for Options {
cli_forced_codegen_units: None,
cli_forced_local_thinlto_off: false,
remap_path_prefix: Vec::new(),
real_rust_source_base_dir: None,
edition: DEFAULT_EDITION,
json_artifact_notifications: false,
json_unused_externs: JsonUnusedExterns::No,
Expand Down Expand Up @@ -2780,7 +2779,7 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M

let cg = cg;

let sysroot_opt = matches.opt_str("sysroot").map(|m| PathBuf::from(&m));
let maybe_sysroot = matches.opt_str("sysroot").map(|m| PathBuf::from(&m));
let target_triple = parse_target_triple(early_dcx, matches);
let opt_level = parse_opt_level(early_dcx, matches, &cg);
// The `-g` and `-C debuginfo` flags specify the same setting, so we want to be able
Expand Down Expand Up @@ -2823,26 +2822,6 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M

let logical_env = parse_logical_env(early_dcx, matches);

let sysroot = filesearch::materialize_sysroot(sysroot_opt);

let real_rust_source_base_dir = {
// This is the location used by the `rust-src` `rustup` component.
let mut candidate = sysroot.join("lib/rustlib/src/rust");
if let Ok(metadata) = candidate.symlink_metadata() {
// Replace the symlink rustbuild creates, with its destination.
// We could try to use `fs::canonicalize` instead, but that might
// produce unnecessarily verbose path.
if metadata.file_type().is_symlink() {
if let Ok(symlink_dest) = std::fs::read_link(&candidate) {
candidate = symlink_dest;
}
}
}

// Only use this directory if it has a file we can expect to always find.
candidate.join("library/std/src/lib.rs").is_file().then_some(candidate)
};

let working_dir = std::env::current_dir().unwrap_or_else(|e| {
early_dcx.early_fatal(format!("Current directory is invalid: {e}"));
});
Expand All @@ -2868,7 +2847,7 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
describe_lints,
output_types,
search_paths,
maybe_sysroot: Some(sysroot),
maybe_sysroot,
target_triple,
test,
incremental,
Expand All @@ -2889,7 +2868,6 @@ pub fn build_session_options(early_dcx: &mut EarlyDiagCtxt, matches: &getopts::M
cli_forced_codegen_units: codegen_units,
cli_forced_local_thinlto_off: disable_local_thinlto,
remap_path_prefix,
real_rust_source_base_dir,
edition,
json_artifact_notifications,
json_unused_externs,
Expand Down
8 changes: 0 additions & 8 deletions compiler/rustc_session/src/options.rs
View file
Expand Up @@ -197,14 +197,6 @@ top_level_options!(

/// Remap source path prefixes in all output (messages, object files, debug, etc.).
remap_path_prefix: Vec<(PathBuf, PathBuf)> [TRACKED_NO_CRATE_HASH],
/// Base directory containing the `src/` for the Rust standard library, and
/// potentially `rustc` as well, if we can find it. Right now it's always
/// `$sysroot/lib/rustlib/src/rust` (i.e. the `rustup` `rust-src` component).
///
/// This directory is what the virtual `/rustc/$hash` is translated back to,
/// if Rust was built with path remapping to `/rustc/$hash` enabled
/// (the `rust.remap-debuginfo` option in `config.toml`).
real_rust_source_base_dir: Option<PathBuf> [TRACKED_NO_CRATE_HASH],

edition: Edition [TRACKED],

Expand Down
26 changes: 26 additions & 0 deletions compiler/rustc_session/src/session.rs
View file
Expand Up @@ -616,6 +616,32 @@ impl Session {
.default_hidden_visibility
.unwrap_or(self.target.options.default_hidden_visibility)
}

/// Base directory containing the `src/` for the Rust standard library, and
/// potentially `rustc` as well, if we can find it. Right now it's always
/// `$sysroot/lib/rustlib/src/rust` (i.e. the `rustup` `rust-src` component).
///
/// This directory is what the virtual `/rustc/$hash` is translated back to,
/// if Rust was built with path remapping to `/rustc/$hash` enabled
/// (the `rust.remap-debuginfo` option in `config.toml`).
pub fn real_rust_source_base_dir(&self) -> Option<PathBuf> {
// This is the location used by the `rust-src` `rustup` component.
let sysroot = filesearch::materialize_sysroot(self.opts.maybe_sysroot.clone());
let mut candidate = sysroot.join("lib/rustlib/src/rust");
if let Ok(metadata) = candidate.symlink_metadata() {
// Replace the symlink rustbuild creates, with its destination.
// We could try to use `fs::canonicalize` instead, but that might
// produce an unnecessarily verbose path.
if metadata.file_type().is_symlink() {
if let Ok(symlink_dest) = std::fs::read_link(&candidate) {
candidate = symlink_dest;
}
}
}

// Only use this directory if it has a file we can expect to always find.
candidate.join("library/std/src/lib.rs").is_file().then_some(candidate)
}
}

// JUSTIFICATION: defn of the suggested wrapper fns
Expand Down
53 changes: 25 additions & 28 deletions src/tools/miri/src/bin/miri.rs
View file
Expand Up @@ -45,12 +45,34 @@ use rustc_session::{CtfeBacktrace, EarlyDiagCtxt};

use miri::{BacktraceStyle, BorrowTrackerMethod, ProvenanceMode, RetagFields};

fn show_error(msg: &impl std::fmt::Display) -> ! {
eprintln!("fatal error: {msg}");
std::process::exit(1)
}

macro_rules! show_error {
($($tt:tt)*) => { show_error(&format_args!($($tt)*)) };
}

struct MiriCompilerCalls {
miri_config: miri::MiriConfig,
}

fn set_default_sysroot_for_target_crate(config: &mut Config) {
if config.opts.maybe_sysroot.is_none() {
// Overwrite the default.
let miri_sysroot = env::var("MIRI_SYSROOT").unwrap_or_else(|_| {
show_error!(
"Miri was invoked in 'target' mode without `MIRI_SYSROOT` or `--sysroot` being set"
)
});
config.opts.maybe_sysroot = Some(PathBuf::from(miri_sysroot));
}
}

impl rustc_driver::Callbacks for MiriCompilerCalls {
fn config(&mut self, config: &mut Config) {
set_default_sysroot_for_target_crate(config);
config.override_queries = Some(|_, providers| {
providers.extern_queries.used_crate_source = |tcx, cnum| {
let mut providers = Providers::default();
Expand Down Expand Up @@ -130,6 +152,9 @@ struct MiriBeRustCompilerCalls {
impl rustc_driver::Callbacks for MiriBeRustCompilerCalls {
#[allow(rustc::potential_query_instability)] // rustc_codegen_ssa (where this code is copied from) also allows this lint
fn config(&mut self, config: &mut Config) {
if self.target_crate {
set_default_sysroot_for_target_crate(config);
}
if config.opts.prints.is_empty() && self.target_crate {
// Queries overridden here affect the data stored in `rmeta` files of dependencies,
// which will be used later in non-`MIRI_BE_RUSTC` mode.
Expand Down Expand Up @@ -201,15 +226,6 @@ impl rustc_driver::Callbacks for MiriBeRustCompilerCalls {
}
}

fn show_error(msg: &impl std::fmt::Display) -> ! {
eprintln!("fatal error: {msg}");
std::process::exit(1)
}

macro_rules! show_error {
($($tt:tt)*) => { show_error(&format_args!($($tt)*)) };
}

fn rustc_logger_config() -> rustc_log::LoggerConfig {
// Start with the usual env vars.
let mut cfg = rustc_log::LoggerConfig::from_env("RUSTC_LOG");
Expand Down Expand Up @@ -271,25 +287,6 @@ fn run_compiler(
callbacks: &mut (dyn rustc_driver::Callbacks + Send),
using_internal_features: std::sync::Arc<std::sync::atomic::AtomicBool>,
) -> ! {
if target_crate {
// Miri needs a custom sysroot for target crates.
// If no `--sysroot` is given, the `MIRI_SYSROOT` env var is consulted to find where
// that sysroot lives, and that is passed to rustc.
let sysroot_flag = "--sysroot";
if !args.iter().any(|e| e == sysroot_flag) {
// Using the built-in default here would be plain wrong, so we *require*
// the env var to make sure things make sense.
let miri_sysroot = env::var("MIRI_SYSROOT").unwrap_or_else(|_| {
show_error!(
"Miri was invoked in 'target' mode without `MIRI_SYSROOT` or `--sysroot` being set"
)
});

args.push(sysroot_flag.to_owned());
args.push(miri_sysroot);
}
}

// Don't insert `MIRI_DEFAULT_ARGS`, in particular, `--cfg=miri`, if we are building
// a "host" crate. That may cause procedural macros (and probably build scripts) to
// depend on Miri-only symbols, such as `miri_resolve_frame`:
Expand Down

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