| //! cfg and check-cfg configuration |
| //! |
| //! This module contains the definition of [`Cfg`] and [`CheckCfg`] |
| //! as well as the logic for creating the default configuration for a |
| //! given [`Session`]. |
| //! |
| //! It also contains the filling of the well known configs, which should |
| //! ALWAYS be in sync with the default_configuration. |
| //! |
| //! ## Adding a new cfg |
| //! |
| //! Adding a new feature requires two new symbols one for the cfg itself |
| //! and the second one for the unstable feature gate, those are defined in |
| //! `rustc_span::symbol`. |
| //! |
| //! As well as the following points, |
| //! - Add the activation logic in [`default_configuration`] |
| //! - Add the cfg to [`CheckCfg::fill_well_known`] (and related files), |
| //! so that the compiler can know the cfg is expected |
| //! - Add the cfg in [`disallow_cfgs`] to disallow users from setting it via `--cfg` |
| //! - Add the feature gating in `compiler/rustc_feature/src/builtin_attrs.rs` |
| |
| use std::hash::Hash; |
| use std::iter; |
| |
| use rustc_abi::Align; |
| use rustc_ast::ast; |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet}; |
| use rustc_lint_defs::BuiltinLintDiag; |
| use rustc_lint_defs::builtin::EXPLICIT_BUILTIN_CFGS_IN_FLAGS; |
| use rustc_span::{Symbol, sym}; |
| use rustc_target::spec::{PanicStrategy, RelocModel, SanitizerSet, Target}; |
| |
| use crate::Session; |
| use crate::config::{CrateType, FmtDebug}; |
| |
| /// The parsed `--cfg` options that define the compilation environment of the |
| /// crate, used to drive conditional compilation. |
| /// |
| /// An `FxIndexSet` is used to ensure deterministic ordering of error messages |
| /// relating to `--cfg`. |
| pub type Cfg = FxIndexSet<(Symbol, Option<Symbol>)>; |
| |
| /// The parsed `--check-cfg` options. |
| #[derive(Default)] |
| pub struct CheckCfg { |
| /// Is well known names activated |
| pub exhaustive_names: bool, |
| /// Is well known values activated |
| pub exhaustive_values: bool, |
| /// All the expected values for a config name |
| pub expecteds: FxHashMap<Symbol, ExpectedValues<Symbol>>, |
| /// Well known names (only used for diagnostics purposes) |
| pub well_known_names: FxHashSet<Symbol>, |
| } |
| |
| pub enum ExpectedValues<T> { |
| Some(FxHashSet<Option<T>>), |
| Any, |
| } |
| |
| impl<T: Eq + Hash> ExpectedValues<T> { |
| fn insert(&mut self, value: T) -> bool { |
| match self { |
| ExpectedValues::Some(expecteds) => expecteds.insert(Some(value)), |
| ExpectedValues::Any => false, |
| } |
| } |
| } |
| |
| impl<T: Eq + Hash> Extend<T> for ExpectedValues<T> { |
| fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) { |
| match self { |
| ExpectedValues::Some(expecteds) => expecteds.extend(iter.into_iter().map(Some)), |
| ExpectedValues::Any => {} |
| } |
| } |
| } |
| |
| impl<'a, T: Eq + Hash + Copy + 'a> Extend<&'a T> for ExpectedValues<T> { |
| fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I) { |
| match self { |
| ExpectedValues::Some(expecteds) => expecteds.extend(iter.into_iter().map(|a| Some(*a))), |
| ExpectedValues::Any => {} |
| } |
| } |
| } |
| |
| /// Disallow builtin cfgs from the CLI. |
| pub(crate) fn disallow_cfgs(sess: &Session, user_cfgs: &Cfg) { |
| let disallow = |cfg: &(Symbol, Option<Symbol>), controlled_by| { |
| let cfg_name = cfg.0; |
| let cfg = if let Some(value) = cfg.1 { |
| format!(r#"{}="{}""#, cfg_name, value) |
| } else { |
| format!("{}", cfg_name) |
| }; |
| sess.psess.opt_span_buffer_lint( |
| EXPLICIT_BUILTIN_CFGS_IN_FLAGS, |
| None, |
| ast::CRATE_NODE_ID, |
| BuiltinLintDiag::UnexpectedBuiltinCfg { cfg, cfg_name, controlled_by }, |
| ) |
| }; |
| |
| // We want to restrict setting builtin cfgs that will produce incoherent behavior |
| // between the cfg and the rustc cli flag that sets it. |
| // |
| // The tests are in tests/ui/cfg/disallowed-cli-cfgs.rs. |
| |
| // By-default all builtin cfgs are disallowed, only those are allowed: |
| // - test: as it makes sense to the have the `test` cfg active without the builtin |
| // test harness. See Cargo `harness = false` config. |
| // |
| // Cargo `--cfg test`: https://github.com/rust-lang/cargo/blob/bc89bffa5987d4af8f71011c7557119b39e44a65/src/cargo/core/compiler/mod.rs#L1124 |
| |
| for cfg in user_cfgs { |
| match cfg { |
| (sym::overflow_checks, None) => disallow(cfg, "-C overflow-checks"), |
| (sym::debug_assertions, None) => disallow(cfg, "-C debug-assertions"), |
| (sym::ub_checks, None) => disallow(cfg, "-Z ub-checks"), |
| (sym::contract_checks, None) => disallow(cfg, "-Z contract-checks"), |
| (sym::sanitize, None | Some(_)) => disallow(cfg, "-Z sanitizer"), |
| ( |
| sym::sanitizer_cfi_generalize_pointers | sym::sanitizer_cfi_normalize_integers, |
| None | Some(_), |
| ) => disallow(cfg, "-Z sanitizer=cfi"), |
| (sym::proc_macro, None) => disallow(cfg, "--crate-type proc-macro"), |
| (sym::panic, Some(sym::abort | sym::unwind)) => disallow(cfg, "-C panic"), |
| (sym::target_feature, Some(_)) => disallow(cfg, "-C target-feature"), |
| (sym::unix, None) |
| | (sym::windows, None) |
| | (sym::relocation_model, Some(_)) |
| | (sym::target_abi, None | Some(_)) |
| | (sym::target_arch, Some(_)) |
| | (sym::target_endian, Some(_)) |
| | (sym::target_env, None | Some(_)) |
| | (sym::target_family, Some(_)) |
| | (sym::target_os, Some(_)) |
| | (sym::target_pointer_width, Some(_)) |
| | (sym::target_vendor, None | Some(_)) |
| | (sym::target_has_atomic, Some(_)) |
| | (sym::target_has_atomic_equal_alignment, Some(_)) |
| | (sym::target_has_atomic_load_store, Some(_)) |
| | (sym::target_has_reliable_f16, None | Some(_)) |
| | (sym::target_has_reliable_f16_math, None | Some(_)) |
| | (sym::target_has_reliable_f128, None | Some(_)) |
| | (sym::target_has_reliable_f128_math, None | Some(_)) |
| | (sym::target_thread_local, None) => disallow(cfg, "--target"), |
| (sym::fmt_debug, None | Some(_)) => disallow(cfg, "-Z fmt-debug"), |
| (sym::emscripten_wasm_eh, None | Some(_)) => disallow(cfg, "-Z emscripten_wasm_eh"), |
| _ => {} |
| } |
| } |
| } |
| |
| /// Generate the default configs for a given session |
| pub(crate) fn default_configuration(sess: &Session) -> Cfg { |
| let mut ret = Cfg::default(); |
| |
| macro_rules! ins_none { |
| ($key:expr) => { |
| ret.insert(($key, None)); |
| }; |
| } |
| macro_rules! ins_str { |
| ($key:expr, $val_str:expr) => { |
| ret.insert(($key, Some(Symbol::intern($val_str)))); |
| }; |
| } |
| macro_rules! ins_sym { |
| ($key:expr, $val_sym:expr) => { |
| ret.insert(($key, Some($val_sym))); |
| }; |
| } |
| |
| // Symbols are inserted in alphabetical order as much as possible. |
| // The exceptions are where control flow forces things out of order. |
| // |
| // Run `rustc --print cfg` to see the configuration in practice. |
| // |
| // NOTE: These insertions should be kept in sync with |
| // `CheckCfg::fill_well_known` below. |
| |
| if sess.opts.debug_assertions { |
| ins_none!(sym::debug_assertions); |
| } |
| |
| if sess.is_nightly_build() { |
| match sess.opts.unstable_opts.fmt_debug { |
| FmtDebug::Full => { |
| ins_sym!(sym::fmt_debug, sym::full); |
| } |
| FmtDebug::Shallow => { |
| ins_sym!(sym::fmt_debug, sym::shallow); |
| } |
| FmtDebug::None => { |
| ins_sym!(sym::fmt_debug, sym::none); |
| } |
| } |
| } |
| |
| if sess.overflow_checks() { |
| ins_none!(sym::overflow_checks); |
| } |
| |
| ins_sym!(sym::panic, sess.panic_strategy().desc_symbol()); |
| |
| // JUSTIFICATION: before wrapper fn is available |
| #[allow(rustc::bad_opt_access)] |
| if sess.opts.crate_types.contains(&CrateType::ProcMacro) { |
| ins_none!(sym::proc_macro); |
| } |
| |
| if sess.is_nightly_build() { |
| ins_sym!(sym::relocation_model, sess.target.relocation_model.desc_symbol()); |
| } |
| |
| for mut s in sess.opts.unstable_opts.sanitizer { |
| // KASAN is still ASAN under the hood, so it uses the same attribute. |
| if s == SanitizerSet::KERNELADDRESS { |
| s = SanitizerSet::ADDRESS; |
| } |
| ins_str!(sym::sanitize, &s.to_string()); |
| } |
| |
| if sess.is_sanitizer_cfi_generalize_pointers_enabled() { |
| ins_none!(sym::sanitizer_cfi_generalize_pointers); |
| } |
| if sess.is_sanitizer_cfi_normalize_integers_enabled() { |
| ins_none!(sym::sanitizer_cfi_normalize_integers); |
| } |
| |
| ins_str!(sym::target_abi, &sess.target.abi); |
| ins_str!(sym::target_arch, &sess.target.arch); |
| ins_str!(sym::target_endian, sess.target.endian.as_str()); |
| ins_str!(sym::target_env, &sess.target.env); |
| |
| for family in sess.target.families.as_ref() { |
| ins_str!(sym::target_family, family); |
| if family == "windows" { |
| ins_none!(sym::windows); |
| } else if family == "unix" { |
| ins_none!(sym::unix); |
| } |
| } |
| |
| // `target_has_atomic*` |
| let layout = sess.target.parse_data_layout().unwrap_or_else(|err| { |
| sess.dcx().emit_fatal(err); |
| }); |
| let mut has_atomic = false; |
| for (i, align) in [ |
| (8, layout.i8_align.abi), |
| (16, layout.i16_align.abi), |
| (32, layout.i32_align.abi), |
| (64, layout.i64_align.abi), |
| (128, layout.i128_align.abi), |
| ] { |
| if i >= sess.target.min_atomic_width() && i <= sess.target.max_atomic_width() { |
| if !has_atomic { |
| has_atomic = true; |
| if sess.is_nightly_build() { |
| if sess.target.atomic_cas { |
| ins_none!(sym::target_has_atomic); |
| } |
| ins_none!(sym::target_has_atomic_load_store); |
| } |
| } |
| let mut insert_atomic = |sym, align: Align| { |
| if sess.target.atomic_cas { |
| ins_sym!(sym::target_has_atomic, sym); |
| } |
| if align.bits() == i { |
| ins_sym!(sym::target_has_atomic_equal_alignment, sym); |
| } |
| ins_sym!(sym::target_has_atomic_load_store, sym); |
| }; |
| insert_atomic(sym::integer(i), align); |
| if sess.target.pointer_width as u64 == i { |
| insert_atomic(sym::ptr, layout.pointer_align().abi); |
| } |
| } |
| } |
| |
| ins_str!(sym::target_os, &sess.target.os); |
| ins_sym!(sym::target_pointer_width, sym::integer(sess.target.pointer_width)); |
| |
| if sess.opts.unstable_opts.has_thread_local.unwrap_or(sess.target.has_thread_local) { |
| ins_none!(sym::target_thread_local); |
| } |
| |
| ins_str!(sym::target_vendor, &sess.target.vendor); |
| |
| // If the user wants a test runner, then add the test cfg. |
| if sess.is_test_crate() { |
| ins_none!(sym::test); |
| } |
| |
| if sess.ub_checks() { |
| ins_none!(sym::ub_checks); |
| } |
| |
| // Nightly-only implementation detail for the `panic_unwind` and `unwind` crates. |
| if sess.is_nightly_build() && sess.opts.unstable_opts.emscripten_wasm_eh { |
| ins_none!(sym::emscripten_wasm_eh); |
| } |
| |
| if sess.contract_checks() { |
| ins_none!(sym::contract_checks); |
| } |
| |
| ret |
| } |
| |
| impl CheckCfg { |
| /// Fill the current [`CheckCfg`] with all the well known cfgs |
| pub fn fill_well_known(&mut self, current_target: &Target) { |
| if !self.exhaustive_values && !self.exhaustive_names { |
| return; |
| } |
| |
| // for `#[cfg(foo)]` (ie. cfg value is none) |
| let no_values = || { |
| let mut values = FxHashSet::default(); |
| values.insert(None); |
| ExpectedValues::Some(values) |
| }; |
| |
| // preparation for inserting some values |
| let empty_values = || { |
| let values = FxHashSet::default(); |
| ExpectedValues::Some(values) |
| }; |
| |
| macro_rules! ins { |
| ($name:expr, $values:expr) => {{ |
| self.well_known_names.insert($name); |
| self.expecteds.entry($name).or_insert_with($values) |
| }}; |
| } |
| |
| // Symbols are inserted in alphabetical order as much as possible. |
| // The exceptions are where control flow forces things out of order. |
| // |
| // NOTE: This should be kept in sync with `default_configuration`. |
| // Note that symbols inserted conditionally in `default_configuration` |
| // are inserted unconditionally here. |
| // |
| // One exception is the `test` cfg which is consider to be a "user-space" |
| // cfg, despite being also set by in `default_configuration` above. |
| // It allows the build system to "deny" using the config by not marking it |
| // as expected (e.g. `lib.test = false` for Cargo). |
| // |
| // When adding a new config here you should also update |
| // `tests/ui/check-cfg/well-known-values.rs` (in order to test the |
| // expected values of the new config) and bless the all directory. |
| // |
| // Don't forget to update `src/doc/rustc/src/check-cfg.md` |
| // in the unstable book as well! |
| |
| ins!(sym::debug_assertions, no_values); |
| |
| ins!(sym::fmt_debug, empty_values).extend(FmtDebug::all()); |
| |
| // These four are never set by rustc, but we set them anyway; they |
| // should not trigger the lint because `cargo clippy`, `cargo doc`, |
| // `cargo test`, `cargo miri run` and `cargo fmt` (respectively) |
| // can set them. |
| ins!(sym::clippy, no_values); |
| ins!(sym::doc, no_values); |
| ins!(sym::doctest, no_values); |
| ins!(sym::miri, no_values); |
| ins!(sym::rustfmt, no_values); |
| |
| ins!(sym::overflow_checks, no_values); |
| |
| ins!(sym::panic, empty_values).extend(&PanicStrategy::all()); |
| |
| ins!(sym::proc_macro, no_values); |
| |
| ins!(sym::relocation_model, empty_values).extend(RelocModel::all()); |
| |
| let sanitize_values = SanitizerSet::all() |
| .into_iter() |
| .map(|sanitizer| Symbol::intern(sanitizer.as_str().unwrap())); |
| ins!(sym::sanitize, empty_values).extend(sanitize_values); |
| |
| ins!(sym::sanitizer_cfi_generalize_pointers, no_values); |
| ins!(sym::sanitizer_cfi_normalize_integers, no_values); |
| |
| ins!(sym::target_feature, empty_values).extend( |
| rustc_target::target_features::all_rust_features() |
| .filter(|(_, s)| s.in_cfg()) |
| .map(|(f, _s)| f) |
| .chain(rustc_target::target_features::RUSTC_SPECIFIC_FEATURES.iter().cloned()) |
| .map(Symbol::intern), |
| ); |
| |
| // sym::target_* |
| { |
| const VALUES: [&Symbol; 8] = [ |
| &sym::target_abi, |
| &sym::target_arch, |
| &sym::target_endian, |
| &sym::target_env, |
| &sym::target_family, |
| &sym::target_os, |
| &sym::target_pointer_width, |
| &sym::target_vendor, |
| ]; |
| |
| // Initialize (if not already initialized) |
| for &e in VALUES { |
| if !self.exhaustive_values { |
| ins!(e, || ExpectedValues::Any); |
| } else { |
| ins!(e, empty_values); |
| } |
| } |
| |
| if self.exhaustive_values { |
| // Get all values map at once otherwise it would be costly. |
| // (8 values * 220 targets ~= 1760 times, at the time of writing this comment). |
| let [ |
| Some(values_target_abi), |
| Some(values_target_arch), |
| Some(values_target_endian), |
| Some(values_target_env), |
| Some(values_target_family), |
| Some(values_target_os), |
| Some(values_target_pointer_width), |
| Some(values_target_vendor), |
| ] = self.expecteds.get_disjoint_mut(VALUES) |
| else { |
| panic!("unable to get all the check-cfg values buckets"); |
| }; |
| |
| for target in Target::builtins().chain(iter::once(current_target.clone())) { |
| values_target_abi.insert(Symbol::intern(&target.options.abi)); |
| values_target_arch.insert(Symbol::intern(&target.arch)); |
| values_target_endian.insert(Symbol::intern(target.options.endian.as_str())); |
| values_target_env.insert(Symbol::intern(&target.options.env)); |
| values_target_family.extend( |
| target.options.families.iter().map(|family| Symbol::intern(family)), |
| ); |
| values_target_os.insert(Symbol::intern(&target.options.os)); |
| values_target_pointer_width.insert(sym::integer(target.pointer_width)); |
| values_target_vendor.insert(Symbol::intern(&target.options.vendor)); |
| } |
| } |
| } |
| |
| let atomic_values = &[ |
| sym::ptr, |
| sym::integer(8usize), |
| sym::integer(16usize), |
| sym::integer(32usize), |
| sym::integer(64usize), |
| sym::integer(128usize), |
| ]; |
| for sym in [ |
| sym::target_has_atomic, |
| sym::target_has_atomic_equal_alignment, |
| sym::target_has_atomic_load_store, |
| ] { |
| ins!(sym, no_values).extend(atomic_values); |
| } |
| |
| ins!(sym::target_thread_local, no_values); |
| |
| ins!(sym::ub_checks, no_values); |
| ins!(sym::contract_checks, no_values); |
| |
| ins!(sym::unix, no_values); |
| ins!(sym::windows, no_values); |
| } |
| } |
