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| -rw-r--r-- | compiler/rustc_span/src/lib.rs | 2116 |
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diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs new file mode 100644 index 000000000..cf3069281 --- /dev/null +++ b/compiler/rustc_span/src/lib.rs @@ -0,0 +1,2116 @@ +//! Source positions and related helper functions. +//! +//! Important concepts in this module include: +//! +//! - the *span*, represented by [`SpanData`] and related types; +//! - source code as represented by a [`SourceMap`]; and +//! - interned strings, represented by [`Symbol`]s, with some common symbols available statically in the [`sym`] module. +//! +//! Unlike most compilers, the span contains not only the position in the source code, but also various other metadata, +//! such as the edition and macro hygiene. This metadata is stored in [`SyntaxContext`] and [`ExpnData`]. +//! +//! ## Note +//! +//! This API is completely unstable and subject to change. + +#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")] +#![feature(array_windows)] +#![feature(let_else)] +#![feature(if_let_guard)] +#![feature(negative_impls)] +#![feature(min_specialization)] +#![feature(rustc_attrs)] + +#[macro_use] +extern crate rustc_macros; + +#[macro_use] +extern crate tracing; + +use rustc_data_structures::AtomicRef; +use rustc_macros::HashStable_Generic; +use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; + +mod caching_source_map_view; +pub mod source_map; +pub use self::caching_source_map_view::CachingSourceMapView; +use source_map::SourceMap; + +pub mod edition; +use edition::Edition; +pub mod hygiene; +use hygiene::Transparency; +pub use hygiene::{DesugaringKind, ExpnKind, MacroKind}; +pub use hygiene::{ExpnData, ExpnHash, ExpnId, LocalExpnId, SyntaxContext}; +use rustc_data_structures::stable_hasher::HashingControls; +pub mod def_id; +use def_id::{CrateNum, DefId, DefPathHash, LocalDefId, LOCAL_CRATE}; +pub mod lev_distance; +mod span_encoding; +pub use span_encoding::{Span, DUMMY_SP}; + +pub mod symbol; +pub use symbol::{sym, Symbol}; + +mod analyze_source_file; +pub mod fatal_error; + +pub mod profiling; + +use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; +use rustc_data_structures::sync::{Lock, Lrc}; + +use std::borrow::Cow; +use std::cmp::{self, Ordering}; +use std::fmt; +use std::hash::Hash; +use std::ops::{Add, Range, Sub}; +use std::path::{Path, PathBuf}; +use std::str::FromStr; +use std::sync::Arc; + +use md5::Digest; +use md5::Md5; +use sha1::Sha1; +use sha2::Sha256; + +use tracing::debug; + +#[cfg(test)] +mod tests; + +// Per-session global variables: this struct is stored in thread-local storage +// in such a way that it is accessible without any kind of handle to all +// threads within the compilation session, but is not accessible outside the +// session. +pub struct SessionGlobals { + symbol_interner: symbol::Interner, + span_interner: Lock<span_encoding::SpanInterner>, + hygiene_data: Lock<hygiene::HygieneData>, + source_map: Lock<Option<Lrc<SourceMap>>>, +} + +impl SessionGlobals { + pub fn new(edition: Edition) -> SessionGlobals { + SessionGlobals { + symbol_interner: symbol::Interner::fresh(), + span_interner: Lock::new(span_encoding::SpanInterner::default()), + hygiene_data: Lock::new(hygiene::HygieneData::new(edition)), + source_map: Lock::new(None), + } + } +} + +#[inline] +pub fn create_session_globals_then<R>(edition: Edition, f: impl FnOnce() -> R) -> R { + assert!( + !SESSION_GLOBALS.is_set(), + "SESSION_GLOBALS should never be overwritten! \ + Use another thread if you need another SessionGlobals" + ); + let session_globals = SessionGlobals::new(edition); + SESSION_GLOBALS.set(&session_globals, f) +} + +#[inline] +pub fn set_session_globals_then<R>(session_globals: &SessionGlobals, f: impl FnOnce() -> R) -> R { + assert!( + !SESSION_GLOBALS.is_set(), + "SESSION_GLOBALS should never be overwritten! \ + Use another thread if you need another SessionGlobals" + ); + SESSION_GLOBALS.set(session_globals, f) +} + +#[inline] +pub fn create_default_session_if_not_set_then<R, F>(f: F) -> R +where + F: FnOnce(&SessionGlobals) -> R, +{ + create_session_if_not_set_then(edition::DEFAULT_EDITION, f) +} + +#[inline] +pub fn create_session_if_not_set_then<R, F>(edition: Edition, f: F) -> R +where + F: FnOnce(&SessionGlobals) -> R, +{ + if !SESSION_GLOBALS.is_set() { + let session_globals = SessionGlobals::new(edition); + SESSION_GLOBALS.set(&session_globals, || SESSION_GLOBALS.with(f)) + } else { + SESSION_GLOBALS.with(f) + } +} + +#[inline] +pub fn with_session_globals<R, F>(f: F) -> R +where + F: FnOnce(&SessionGlobals) -> R, +{ + SESSION_GLOBALS.with(f) +} + +#[inline] +pub fn create_default_session_globals_then<R>(f: impl FnOnce() -> R) -> R { + create_session_globals_then(edition::DEFAULT_EDITION, f) +} + +// If this ever becomes non thread-local, `decode_syntax_context` +// and `decode_expn_id` will need to be updated to handle concurrent +// deserialization. +scoped_tls::scoped_thread_local!(static SESSION_GLOBALS: SessionGlobals); + +// FIXME: We should use this enum or something like it to get rid of the +// use of magic `/rust/1.x/...` paths across the board. +#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd)] +#[derive(Decodable)] +pub enum RealFileName { + LocalPath(PathBuf), + /// For remapped paths (namely paths into libstd that have been mapped + /// to the appropriate spot on the local host's file system, and local file + /// system paths that have been remapped with `FilePathMapping`), + Remapped { + /// `local_path` is the (host-dependent) local path to the file. This is + /// None if the file was imported from another crate + local_path: Option<PathBuf>, + /// `virtual_name` is the stable path rustc will store internally within + /// build artifacts. + virtual_name: PathBuf, + }, +} + +impl Hash for RealFileName { + fn hash<H: std::hash::Hasher>(&self, state: &mut H) { + // To prevent #70924 from happening again we should only hash the + // remapped (virtualized) path if that exists. This is because + // virtualized paths to sysroot crates (/rust/$hash or /rust/$version) + // remain stable even if the corresponding local_path changes + self.remapped_path_if_available().hash(state) + } +} + +// This is functionally identical to #[derive(Encodable)], with the exception of +// an added assert statement +impl<S: Encoder> Encodable<S> for RealFileName { + fn encode(&self, encoder: &mut S) { + match *self { + RealFileName::LocalPath(ref local_path) => encoder.emit_enum_variant(0, |encoder| { + local_path.encode(encoder); + }), + + RealFileName::Remapped { ref local_path, ref virtual_name } => encoder + .emit_enum_variant(1, |encoder| { + // For privacy and build reproducibility, we must not embed host-dependant path in artifacts + // if they have been remapped by --remap-path-prefix + assert!(local_path.is_none()); + local_path.encode(encoder); + virtual_name.encode(encoder); + }), + } + } +} + +impl RealFileName { + /// Returns the path suitable for reading from the file system on the local host, + /// if this information exists. + /// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that. + pub fn local_path(&self) -> Option<&Path> { + match self { + RealFileName::LocalPath(p) => Some(p), + RealFileName::Remapped { local_path: p, virtual_name: _ } => { + p.as_ref().map(PathBuf::as_path) + } + } + } + + /// Returns the path suitable for reading from the file system on the local host, + /// if this information exists. + /// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that. + pub fn into_local_path(self) -> Option<PathBuf> { + match self { + RealFileName::LocalPath(p) => Some(p), + RealFileName::Remapped { local_path: p, virtual_name: _ } => p, + } + } + + /// Returns the path suitable for embedding into build artifacts. This would still + /// be a local path if it has not been remapped. A remapped path will not correspond + /// to a valid file system path: see `local_path_if_available()` for something that + /// is more likely to return paths into the local host file system. + pub fn remapped_path_if_available(&self) -> &Path { + match self { + RealFileName::LocalPath(p) + | RealFileName::Remapped { local_path: _, virtual_name: p } => &p, + } + } + + /// Returns the path suitable for reading from the file system on the local host, + /// if this information exists. Otherwise returns the remapped name. + /// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that. + pub fn local_path_if_available(&self) -> &Path { + match self { + RealFileName::LocalPath(path) + | RealFileName::Remapped { local_path: None, virtual_name: path } + | RealFileName::Remapped { local_path: Some(path), virtual_name: _ } => path, + } + } + + pub fn to_string_lossy(&self, display_pref: FileNameDisplayPreference) -> Cow<'_, str> { + match display_pref { + FileNameDisplayPreference::Local => self.local_path_if_available().to_string_lossy(), + FileNameDisplayPreference::Remapped => { + self.remapped_path_if_available().to_string_lossy() + } + } + } +} + +/// Differentiates between real files and common virtual files. +#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash)] +#[derive(Decodable, Encodable)] +pub enum FileName { + Real(RealFileName), + /// Call to `quote!`. + QuoteExpansion(u64), + /// Command line. + Anon(u64), + /// Hack in `src/librustc_ast/parse.rs`. + // FIXME(jseyfried) + MacroExpansion(u64), + ProcMacroSourceCode(u64), + /// Strings provided as `--cfg [cfgspec]` stored in a `crate_cfg`. + CfgSpec(u64), + /// Strings provided as crate attributes in the CLI. + CliCrateAttr(u64), + /// Custom sources for explicit parser calls from plugins and drivers. + Custom(String), + DocTest(PathBuf, isize), + /// Post-substitution inline assembly from LLVM. + InlineAsm(u64), +} + +impl From<PathBuf> for FileName { + fn from(p: PathBuf) -> Self { + assert!(!p.to_string_lossy().ends_with('>')); + FileName::Real(RealFileName::LocalPath(p)) + } +} + +#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug)] +pub enum FileNameDisplayPreference { + Remapped, + Local, +} + +pub struct FileNameDisplay<'a> { + inner: &'a FileName, + display_pref: FileNameDisplayPreference, +} + +impl fmt::Display for FileNameDisplay<'_> { + fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + use FileName::*; + match *self.inner { + Real(ref name) => { + write!(fmt, "{}", name.to_string_lossy(self.display_pref)) + } + QuoteExpansion(_) => write!(fmt, "<quote expansion>"), + MacroExpansion(_) => write!(fmt, "<macro expansion>"), + Anon(_) => write!(fmt, "<anon>"), + ProcMacroSourceCode(_) => write!(fmt, "<proc-macro source code>"), + CfgSpec(_) => write!(fmt, "<cfgspec>"), + CliCrateAttr(_) => write!(fmt, "<crate attribute>"), + Custom(ref s) => write!(fmt, "<{}>", s), + DocTest(ref path, _) => write!(fmt, "{}", path.display()), + InlineAsm(_) => write!(fmt, "<inline asm>"), + } + } +} + +impl<'a> FileNameDisplay<'a> { + pub fn to_string_lossy(&self) -> Cow<'a, str> { + match self.inner { + FileName::Real(ref inner) => inner.to_string_lossy(self.display_pref), + _ => Cow::from(self.to_string()), + } + } +} + +impl FileName { + pub fn is_real(&self) -> bool { + use FileName::*; + match *self { + Real(_) => true, + Anon(_) + | MacroExpansion(_) + | ProcMacroSourceCode(_) + | CfgSpec(_) + | CliCrateAttr(_) + | Custom(_) + | QuoteExpansion(_) + | DocTest(_, _) + | InlineAsm(_) => false, + } + } + + pub fn prefer_remapped(&self) -> FileNameDisplay<'_> { + FileNameDisplay { inner: self, display_pref: FileNameDisplayPreference::Remapped } + } + + // This may include transient local filesystem information. + // Must not be embedded in build outputs. + pub fn prefer_local(&self) -> FileNameDisplay<'_> { + FileNameDisplay { inner: self, display_pref: FileNameDisplayPreference::Local } + } + + pub fn display(&self, display_pref: FileNameDisplayPreference) -> FileNameDisplay<'_> { + FileNameDisplay { inner: self, display_pref } + } + + pub fn macro_expansion_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::MacroExpansion(hasher.finish()) + } + + pub fn anon_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::Anon(hasher.finish()) + } + + pub fn proc_macro_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::ProcMacroSourceCode(hasher.finish()) + } + + pub fn cfg_spec_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::QuoteExpansion(hasher.finish()) + } + + pub fn cli_crate_attr_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::CliCrateAttr(hasher.finish()) + } + + pub fn doc_test_source_code(path: PathBuf, line: isize) -> FileName { + FileName::DocTest(path, line) + } + + pub fn inline_asm_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::InlineAsm(hasher.finish()) + } +} + +/// Represents a span. +/// +/// Spans represent a region of code, used for error reporting. Positions in spans +/// are *absolute* positions from the beginning of the [`SourceMap`], not positions +/// relative to [`SourceFile`]s. Methods on the `SourceMap` can be used to relate spans back +/// to the original source. +/// +/// You must be careful if the span crosses more than one file, since you will not be +/// able to use many of the functions on spans in source_map and you cannot assume +/// that the length of the span is equal to `span.hi - span.lo`; there may be space in the +/// [`BytePos`] range between files. +/// +/// `SpanData` is public because `Span` uses a thread-local interner and can't be +/// sent to other threads, but some pieces of performance infra run in a separate thread. +/// Using `Span` is generally preferred. +#[derive(Clone, Copy, Hash, PartialEq, Eq)] +pub struct SpanData { + pub lo: BytePos, + pub hi: BytePos, + /// Information about where the macro came from, if this piece of + /// code was created by a macro expansion. + pub ctxt: SyntaxContext, + pub parent: Option<LocalDefId>, +} + +// Order spans by position in the file. +impl Ord for SpanData { + fn cmp(&self, other: &Self) -> Ordering { + let SpanData { + lo: s_lo, + hi: s_hi, + ctxt: s_ctxt, + // `LocalDefId` does not implement `Ord`. + // The other fields are enough to determine in-file order. + parent: _, + } = self; + let SpanData { + lo: o_lo, + hi: o_hi, + ctxt: o_ctxt, + // `LocalDefId` does not implement `Ord`. + // The other fields are enough to determine in-file order. + parent: _, + } = other; + + (s_lo, s_hi, s_ctxt).cmp(&(o_lo, o_hi, o_ctxt)) + } +} + +impl PartialOrd for SpanData { + fn partial_cmp(&self, other: &Self) -> Option<Ordering> { + Some(self.cmp(other)) + } +} + +impl SpanData { + #[inline] + pub fn span(&self) -> Span { + Span::new(self.lo, self.hi, self.ctxt, self.parent) + } + #[inline] + pub fn with_lo(&self, lo: BytePos) -> Span { + Span::new(lo, self.hi, self.ctxt, self.parent) + } + #[inline] + pub fn with_hi(&self, hi: BytePos) -> Span { + Span::new(self.lo, hi, self.ctxt, self.parent) + } + #[inline] + pub fn with_ctxt(&self, ctxt: SyntaxContext) -> Span { + Span::new(self.lo, self.hi, ctxt, self.parent) + } + #[inline] + pub fn with_parent(&self, parent: Option<LocalDefId>) -> Span { + Span::new(self.lo, self.hi, self.ctxt, parent) + } + /// Returns `true` if this is a dummy span with any hygienic context. + #[inline] + pub fn is_dummy(self) -> bool { + self.lo.0 == 0 && self.hi.0 == 0 + } + /// Returns `true` if `self` fully encloses `other`. + pub fn contains(self, other: Self) -> bool { + self.lo <= other.lo && other.hi <= self.hi + } +} + +// The interner is pointed to by a thread local value which is only set on the main thread +// with parallelization is disabled. So we don't allow `Span` to transfer between threads +// to avoid panics and other errors, even though it would be memory safe to do so. +#[cfg(not(parallel_compiler))] +impl !Send for Span {} +#[cfg(not(parallel_compiler))] +impl !Sync for Span {} + +impl PartialOrd for Span { + fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> { + PartialOrd::partial_cmp(&self.data(), &rhs.data()) + } +} +impl Ord for Span { + fn cmp(&self, rhs: &Self) -> Ordering { + Ord::cmp(&self.data(), &rhs.data()) + } +} + +impl Span { + #[inline] + pub fn lo(self) -> BytePos { + self.data().lo + } + #[inline] + pub fn with_lo(self, lo: BytePos) -> Span { + self.data().with_lo(lo) + } + #[inline] + pub fn hi(self) -> BytePos { + self.data().hi + } + #[inline] + pub fn with_hi(self, hi: BytePos) -> Span { + self.data().with_hi(hi) + } + #[inline] + pub fn ctxt(self) -> SyntaxContext { + self.data_untracked().ctxt + } + pub fn eq_ctxt(self, other: Span) -> bool { + self.data_untracked().ctxt == other.data_untracked().ctxt + } + #[inline] + pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span { + self.data_untracked().with_ctxt(ctxt) + } + #[inline] + pub fn parent(self) -> Option<LocalDefId> { + self.data().parent + } + #[inline] + pub fn with_parent(self, ctxt: Option<LocalDefId>) -> Span { + self.data().with_parent(ctxt) + } + + /// Returns `true` if this is a dummy span with any hygienic context. + #[inline] + pub fn is_dummy(self) -> bool { + self.data_untracked().is_dummy() + } + + /// Returns `true` if this span comes from a macro or desugaring. + #[inline] + pub fn from_expansion(self) -> bool { + self.ctxt() != SyntaxContext::root() + } + + /// Returns `true` if `span` originates in a derive-macro's expansion. + pub fn in_derive_expansion(self) -> bool { + matches!(self.ctxt().outer_expn_data().kind, ExpnKind::Macro(MacroKind::Derive, _)) + } + + /// Gate suggestions that would not be appropriate in a context the user didn't write. + pub fn can_be_used_for_suggestions(self) -> bool { + !self.from_expansion() + // FIXME: If this span comes from a `derive` macro but it points at code the user wrote, + // the callsite span and the span will be pointing at different places. It also means that + // we can safely provide suggestions on this span. + || (matches!(self.ctxt().outer_expn_data().kind, ExpnKind::Macro(MacroKind::Derive, _)) + && self.parent_callsite().map(|p| (p.lo(), p.hi())) != Some((self.lo(), self.hi()))) + } + + #[inline] + pub fn with_root_ctxt(lo: BytePos, hi: BytePos) -> Span { + Span::new(lo, hi, SyntaxContext::root(), None) + } + + /// Returns a new span representing an empty span at the beginning of this span. + #[inline] + pub fn shrink_to_lo(self) -> Span { + let span = self.data_untracked(); + span.with_hi(span.lo) + } + /// Returns a new span representing an empty span at the end of this span. + #[inline] + pub fn shrink_to_hi(self) -> Span { + let span = self.data_untracked(); + span.with_lo(span.hi) + } + + #[inline] + /// Returns `true` if `hi == lo`. + pub fn is_empty(self) -> bool { + let span = self.data_untracked(); + span.hi == span.lo + } + + /// Returns `self` if `self` is not the dummy span, and `other` otherwise. + pub fn substitute_dummy(self, other: Span) -> Span { + if self.is_dummy() { other } else { self } + } + + /// Returns `true` if `self` fully encloses `other`. + pub fn contains(self, other: Span) -> bool { + let span = self.data(); + let other = other.data(); + span.contains(other) + } + + /// Returns `true` if `self` touches `other`. + pub fn overlaps(self, other: Span) -> bool { + let span = self.data(); + let other = other.data(); + span.lo < other.hi && other.lo < span.hi + } + + /// Returns `true` if the spans are equal with regards to the source text. + /// + /// Use this instead of `==` when either span could be generated code, + /// and you only care that they point to the same bytes of source text. + pub fn source_equal(self, other: Span) -> bool { + let span = self.data(); + let other = other.data(); + span.lo == other.lo && span.hi == other.hi + } + + /// Returns `Some(span)`, where the start is trimmed by the end of `other`. + pub fn trim_start(self, other: Span) -> Option<Span> { + let span = self.data(); + let other = other.data(); + if span.hi > other.hi { Some(span.with_lo(cmp::max(span.lo, other.hi))) } else { None } + } + + /// Returns the source span -- this is either the supplied span, or the span for + /// the macro callsite that expanded to it. + pub fn source_callsite(self) -> Span { + let expn_data = self.ctxt().outer_expn_data(); + if !expn_data.is_root() { expn_data.call_site.source_callsite() } else { self } + } + + /// The `Span` for the tokens in the previous macro expansion from which `self` was generated, + /// if any. + pub fn parent_callsite(self) -> Option<Span> { + let expn_data = self.ctxt().outer_expn_data(); + if !expn_data.is_root() { Some(expn_data.call_site) } else { None } + } + + /// Walk down the expansion ancestors to find a span that's contained within `outer`. + pub fn find_ancestor_inside(mut self, outer: Span) -> Option<Span> { + while !outer.contains(self) { + self = self.parent_callsite()?; + } + Some(self) + } + + /// Edition of the crate from which this span came. + pub fn edition(self) -> edition::Edition { + self.ctxt().edition() + } + + #[inline] + pub fn rust_2015(self) -> bool { + self.edition() == edition::Edition::Edition2015 + } + + #[inline] + pub fn rust_2018(self) -> bool { + self.edition() >= edition::Edition::Edition2018 + } + + #[inline] + pub fn rust_2021(self) -> bool { + self.edition() >= edition::Edition::Edition2021 + } + + #[inline] + pub fn rust_2024(self) -> bool { + self.edition() >= edition::Edition::Edition2024 + } + + /// Returns the source callee. + /// + /// Returns `None` if the supplied span has no expansion trace, + /// else returns the `ExpnData` for the macro definition + /// corresponding to the source callsite. + pub fn source_callee(self) -> Option<ExpnData> { + fn source_callee(expn_data: ExpnData) -> ExpnData { + let next_expn_data = expn_data.call_site.ctxt().outer_expn_data(); + if !next_expn_data.is_root() { source_callee(next_expn_data) } else { expn_data } + } + let expn_data = self.ctxt().outer_expn_data(); + if !expn_data.is_root() { Some(source_callee(expn_data)) } else { None } + } + + /// Checks if a span is "internal" to a macro in which `#[unstable]` + /// items can be used (that is, a macro marked with + /// `#[allow_internal_unstable]`). + pub fn allows_unstable(self, feature: Symbol) -> bool { + self.ctxt() + .outer_expn_data() + .allow_internal_unstable + .map_or(false, |features| features.iter().any(|&f| f == feature)) + } + + /// Checks if this span arises from a compiler desugaring of kind `kind`. + pub fn is_desugaring(self, kind: DesugaringKind) -> bool { + match self.ctxt().outer_expn_data().kind { + ExpnKind::Desugaring(k) => k == kind, + _ => false, + } + } + + /// Returns the compiler desugaring that created this span, or `None` + /// if this span is not from a desugaring. + pub fn desugaring_kind(self) -> Option<DesugaringKind> { + match self.ctxt().outer_expn_data().kind { + ExpnKind::Desugaring(k) => Some(k), + _ => None, + } + } + + /// Checks if a span is "internal" to a macro in which `unsafe` + /// can be used without triggering the `unsafe_code` lint. + // (that is, a macro marked with `#[allow_internal_unsafe]`). + pub fn allows_unsafe(self) -> bool { + self.ctxt().outer_expn_data().allow_internal_unsafe + } + + pub fn macro_backtrace(mut self) -> impl Iterator<Item = ExpnData> { + let mut prev_span = DUMMY_SP; + std::iter::from_fn(move || { + loop { + let expn_data = self.ctxt().outer_expn_data(); + if expn_data.is_root() { + return None; + } + + let is_recursive = expn_data.call_site.source_equal(prev_span); + + prev_span = self; + self = expn_data.call_site; + + // Don't print recursive invocations. + if !is_recursive { + return Some(expn_data); + } + } + }) + } + + /// Returns a `Span` that would enclose both `self` and `end`. + /// + /// ```text + /// ____ ___ + /// self lorem ipsum end + /// ^^^^^^^^^^^^^^^^^^^^ + /// ``` + pub fn to(self, end: Span) -> Span { + let span_data = self.data(); + let end_data = end.data(); + // FIXME(jseyfried): `self.ctxt` should always equal `end.ctxt` here (cf. issue #23480). + // Return the macro span on its own to avoid weird diagnostic output. It is preferable to + // have an incomplete span than a completely nonsensical one. + if span_data.ctxt != end_data.ctxt { + if span_data.ctxt == SyntaxContext::root() { + return end; + } else if end_data.ctxt == SyntaxContext::root() { + return self; + } + // Both spans fall within a macro. + // FIXME(estebank): check if it is the *same* macro. + } + Span::new( + cmp::min(span_data.lo, end_data.lo), + cmp::max(span_data.hi, end_data.hi), + if span_data.ctxt == SyntaxContext::root() { end_data.ctxt } else { span_data.ctxt }, + if span_data.parent == end_data.parent { span_data.parent } else { None }, + ) + } + + /// Returns a `Span` between the end of `self` to the beginning of `end`. + /// + /// ```text + /// ____ ___ + /// self lorem ipsum end + /// ^^^^^^^^^^^^^ + /// ``` + pub fn between(self, end: Span) -> Span { + let span = self.data(); + let end = end.data(); + Span::new( + span.hi, + end.lo, + if end.ctxt == SyntaxContext::root() { end.ctxt } else { span.ctxt }, + if span.parent == end.parent { span.parent } else { None }, + ) + } + + /// Returns a `Span` from the beginning of `self` until the beginning of `end`. + /// + /// ```text + /// ____ ___ + /// self lorem ipsum end + /// ^^^^^^^^^^^^^^^^^ + /// ``` + pub fn until(self, end: Span) -> Span { + // Most of this function's body is copied from `to`. + // We can't just do `self.to(end.shrink_to_lo())`, + // because to also does some magic where it uses min/max so + // it can handle overlapping spans. Some advanced mis-use of + // `until` with different ctxts makes this visible. + let span_data = self.data(); + let end_data = end.data(); + // FIXME(jseyfried): `self.ctxt` should always equal `end.ctxt` here (cf. issue #23480). + // Return the macro span on its own to avoid weird diagnostic output. It is preferable to + // have an incomplete span than a completely nonsensical one. + if span_data.ctxt != end_data.ctxt { + if span_data.ctxt == SyntaxContext::root() { + return end; + } else if end_data.ctxt == SyntaxContext::root() { + return self; + } + // Both spans fall within a macro. + // FIXME(estebank): check if it is the *same* macro. + } + Span::new( + span_data.lo, + end_data.lo, + if end_data.ctxt == SyntaxContext::root() { end_data.ctxt } else { span_data.ctxt }, + if span_data.parent == end_data.parent { span_data.parent } else { None }, + ) + } + + pub fn from_inner(self, inner: InnerSpan) -> Span { + let span = self.data(); + Span::new( + span.lo + BytePos::from_usize(inner.start), + span.lo + BytePos::from_usize(inner.end), + span.ctxt, + span.parent, + ) + } + + /// Equivalent of `Span::def_site` from the proc macro API, + /// except that the location is taken from the `self` span. + pub fn with_def_site_ctxt(self, expn_id: ExpnId) -> Span { + self.with_ctxt_from_mark(expn_id, Transparency::Opaque) + } + + /// Equivalent of `Span::call_site` from the proc macro API, + /// except that the location is taken from the `self` span. + pub fn with_call_site_ctxt(self, expn_id: ExpnId) -> Span { + self.with_ctxt_from_mark(expn_id, Transparency::Transparent) + } + + /// Equivalent of `Span::mixed_site` from the proc macro API, + /// except that the location is taken from the `self` span. + pub fn with_mixed_site_ctxt(self, expn_id: ExpnId) -> Span { + self.with_ctxt_from_mark(expn_id, Transparency::SemiTransparent) + } + + /// Produces a span with the same location as `self` and context produced by a macro with the + /// given ID and transparency, assuming that macro was defined directly and not produced by + /// some other macro (which is the case for built-in and procedural macros). + pub fn with_ctxt_from_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span { + self.with_ctxt(SyntaxContext::root().apply_mark(expn_id, transparency)) + } + + #[inline] + pub fn apply_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span { + let span = self.data(); + span.with_ctxt(span.ctxt.apply_mark(expn_id, transparency)) + } + + #[inline] + pub fn remove_mark(&mut self) -> ExpnId { + let mut span = self.data(); + let mark = span.ctxt.remove_mark(); + *self = Span::new(span.lo, span.hi, span.ctxt, span.parent); + mark + } + + #[inline] + pub fn adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> { + let mut span = self.data(); + let mark = span.ctxt.adjust(expn_id); + *self = Span::new(span.lo, span.hi, span.ctxt, span.parent); + mark + } + + #[inline] + pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> { + let mut span = self.data(); + let mark = span.ctxt.normalize_to_macros_2_0_and_adjust(expn_id); + *self = Span::new(span.lo, span.hi, span.ctxt, span.parent); + mark + } + + #[inline] + pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option<Option<ExpnId>> { + let mut span = self.data(); + let mark = span.ctxt.glob_adjust(expn_id, glob_span); + *self = Span::new(span.lo, span.hi, span.ctxt, span.parent); + mark + } + + #[inline] + pub fn reverse_glob_adjust( + &mut self, + expn_id: ExpnId, + glob_span: Span, + ) -> Option<Option<ExpnId>> { + let mut span = self.data(); + let mark = span.ctxt.reverse_glob_adjust(expn_id, glob_span); + *self = Span::new(span.lo, span.hi, span.ctxt, span.parent); + mark + } + + #[inline] + pub fn normalize_to_macros_2_0(self) -> Span { + let span = self.data(); + span.with_ctxt(span.ctxt.normalize_to_macros_2_0()) + } + + #[inline] + pub fn normalize_to_macro_rules(self) -> Span { + let span = self.data(); + span.with_ctxt(span.ctxt.normalize_to_macro_rules()) + } +} + +impl Default for Span { + fn default() -> Self { + DUMMY_SP + } +} + +impl<E: Encoder> Encodable<E> for Span { + default fn encode(&self, s: &mut E) { + let span = self.data(); + span.lo.encode(s); + span.hi.encode(s); + } +} +impl<D: Decoder> Decodable<D> for Span { + default fn decode(s: &mut D) -> Span { + let lo = Decodable::decode(s); + let hi = Decodable::decode(s); + + Span::new(lo, hi, SyntaxContext::root(), None) + } +} + +/// Calls the provided closure, using the provided `SourceMap` to format +/// any spans that are debug-printed during the closure's execution. +/// +/// Normally, the global `TyCtxt` is used to retrieve the `SourceMap` +/// (see `rustc_interface::callbacks::span_debug1`). However, some parts +/// of the compiler (e.g. `rustc_parse`) may debug-print `Span`s before +/// a `TyCtxt` is available. In this case, we fall back to +/// the `SourceMap` provided to this function. If that is not available, +/// we fall back to printing the raw `Span` field values. +pub fn with_source_map<T, F: FnOnce() -> T>(source_map: Lrc<SourceMap>, f: F) -> T { + with_session_globals(|session_globals| { + *session_globals.source_map.borrow_mut() = Some(source_map); + }); + struct ClearSourceMap; + impl Drop for ClearSourceMap { + fn drop(&mut self) { + with_session_globals(|session_globals| { + session_globals.source_map.borrow_mut().take(); + }); + } + } + + let _guard = ClearSourceMap; + f() +} + +impl fmt::Debug for Span { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + with_session_globals(|session_globals| { + if let Some(source_map) = &*session_globals.source_map.borrow() { + write!(f, "{} ({:?})", source_map.span_to_diagnostic_string(*self), self.ctxt()) + } else { + f.debug_struct("Span") + .field("lo", &self.lo()) + .field("hi", &self.hi()) + .field("ctxt", &self.ctxt()) + .finish() + } + }) + } +} + +impl fmt::Debug for SpanData { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + fmt::Debug::fmt(&Span::new(self.lo, self.hi, self.ctxt, self.parent), f) + } +} + +/// Identifies an offset of a multi-byte character in a `SourceFile`. +#[derive(Copy, Clone, Encodable, Decodable, Eq, PartialEq, Debug)] +pub struct MultiByteChar { + /// The absolute offset of the character in the `SourceMap`. + pub pos: BytePos, + /// The number of bytes, `>= 2`. + pub bytes: u8, +} + +/// Identifies an offset of a non-narrow character in a `SourceFile`. +#[derive(Copy, Clone, Encodable, Decodable, Eq, PartialEq, Debug)] +pub enum NonNarrowChar { + /// Represents a zero-width character. + ZeroWidth(BytePos), + /// Represents a wide (full-width) character. + Wide(BytePos), + /// Represents a tab character, represented visually with a width of 4 characters. + Tab(BytePos), +} + +impl NonNarrowChar { + fn new(pos: BytePos, width: usize) -> Self { + match width { + 0 => NonNarrowChar::ZeroWidth(pos), + 2 => NonNarrowChar::Wide(pos), + 4 => NonNarrowChar::Tab(pos), + _ => panic!("width {} given for non-narrow character", width), + } + } + + /// Returns the absolute offset of the character in the `SourceMap`. + pub fn pos(&self) -> BytePos { + match *self { + NonNarrowChar::ZeroWidth(p) | NonNarrowChar::Wide(p) | NonNarrowChar::Tab(p) => p, + } + } + + /// Returns the width of the character, 0 (zero-width) or 2 (wide). + pub fn width(&self) -> usize { + match *self { + NonNarrowChar::ZeroWidth(_) => 0, + NonNarrowChar::Wide(_) => 2, + NonNarrowChar::Tab(_) => 4, + } + } +} + +impl Add<BytePos> for NonNarrowChar { + type Output = Self; + + fn add(self, rhs: BytePos) -> Self { + match self { + NonNarrowChar::ZeroWidth(pos) => NonNarrowChar::ZeroWidth(pos + rhs), + NonNarrowChar::Wide(pos) => NonNarrowChar::Wide(pos + rhs), + NonNarrowChar::Tab(pos) => NonNarrowChar::Tab(pos + rhs), + } + } +} + +impl Sub<BytePos> for NonNarrowChar { + type Output = Self; + + fn sub(self, rhs: BytePos) -> Self { + match self { + NonNarrowChar::ZeroWidth(pos) => NonNarrowChar::ZeroWidth(pos - rhs), + NonNarrowChar::Wide(pos) => NonNarrowChar::Wide(pos - rhs), + NonNarrowChar::Tab(pos) => NonNarrowChar::Tab(pos - rhs), + } + } +} + +/// Identifies an offset of a character that was normalized away from `SourceFile`. +#[derive(Copy, Clone, Encodable, Decodable, Eq, PartialEq, Debug)] +pub struct NormalizedPos { + /// The absolute offset of the character in the `SourceMap`. + pub pos: BytePos, + /// The difference between original and normalized string at position. + pub diff: u32, +} + +#[derive(PartialEq, Eq, Clone, Debug)] +pub enum ExternalSource { + /// No external source has to be loaded, since the `SourceFile` represents a local crate. + Unneeded, + Foreign { + kind: ExternalSourceKind, + /// This SourceFile's byte-offset within the source_map of its original crate. + original_start_pos: BytePos, + /// The end of this SourceFile within the source_map of its original crate. + original_end_pos: BytePos, + }, +} + +/// The state of the lazy external source loading mechanism of a `SourceFile`. +#[derive(PartialEq, Eq, Clone, Debug)] +pub enum ExternalSourceKind { + /// The external source has been loaded already. + Present(Lrc<String>), + /// No attempt has been made to load the external source. + AbsentOk, + /// A failed attempt has been made to load the external source. + AbsentErr, + Unneeded, +} + +impl ExternalSource { + pub fn get_source(&self) -> Option<&Lrc<String>> { + match self { + ExternalSource::Foreign { kind: ExternalSourceKind::Present(ref src), .. } => Some(src), + _ => None, + } + } +} + +#[derive(Debug)] +pub struct OffsetOverflowError; + +#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)] +#[derive(HashStable_Generic)] +pub enum SourceFileHashAlgorithm { + Md5, + Sha1, + Sha256, +} + +impl FromStr for SourceFileHashAlgorithm { + type Err = (); + + fn from_str(s: &str) -> Result<SourceFileHashAlgorithm, ()> { + match s { + "md5" => Ok(SourceFileHashAlgorithm::Md5), + "sha1" => Ok(SourceFileHashAlgorithm::Sha1), + "sha256" => Ok(SourceFileHashAlgorithm::Sha256), + _ => Err(()), + } + } +} + +/// The hash of the on-disk source file used for debug info. +#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)] +#[derive(HashStable_Generic, Encodable, Decodable)] +pub struct SourceFileHash { + pub kind: SourceFileHashAlgorithm, + value: [u8; 32], +} + +impl SourceFileHash { + pub fn new(kind: SourceFileHashAlgorithm, src: &str) -> SourceFileHash { + let mut hash = SourceFileHash { kind, value: Default::default() }; + let len = hash.hash_len(); + let value = &mut hash.value[..len]; + let data = src.as_bytes(); + match kind { + SourceFileHashAlgorithm::Md5 => { + value.copy_from_slice(&Md5::digest(data)); + } + SourceFileHashAlgorithm::Sha1 => { + value.copy_from_slice(&Sha1::digest(data)); + } + SourceFileHashAlgorithm::Sha256 => { + value.copy_from_slice(&Sha256::digest(data)); + } + } + hash + } + + /// Check if the stored hash matches the hash of the string. + pub fn matches(&self, src: &str) -> bool { + Self::new(self.kind, src) == *self + } + + /// The bytes of the hash. + pub fn hash_bytes(&self) -> &[u8] { + let len = self.hash_len(); + &self.value[..len] + } + + fn hash_len(&self) -> usize { + match self.kind { + SourceFileHashAlgorithm::Md5 => 16, + SourceFileHashAlgorithm::Sha1 => 20, + SourceFileHashAlgorithm::Sha256 => 32, + } + } +} + +#[derive(HashStable_Generic)] +#[derive(Copy, PartialEq, PartialOrd, Clone, Ord, Eq, Hash, Debug, Encodable, Decodable)] +pub enum DebuggerVisualizerType { + Natvis, + GdbPrettyPrinter, +} + +/// A single debugger visualizer file. +#[derive(HashStable_Generic)] +#[derive(Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord, Encodable, Decodable)] +pub struct DebuggerVisualizerFile { + /// The complete debugger visualizer source. + pub src: Arc<[u8]>, + /// Indicates which visualizer type this targets. + pub visualizer_type: DebuggerVisualizerType, +} + +impl DebuggerVisualizerFile { + pub fn new(src: Arc<[u8]>, visualizer_type: DebuggerVisualizerType) -> Self { + DebuggerVisualizerFile { src, visualizer_type } + } +} + +#[derive(Clone)] +pub enum SourceFileLines { + /// The source file lines, in decoded (random-access) form. + Lines(Vec<BytePos>), + + /// The source file lines, in undecoded difference list form. + Diffs(SourceFileDiffs), +} + +impl SourceFileLines { + pub fn is_lines(&self) -> bool { + matches!(self, SourceFileLines::Lines(_)) + } +} + +/// The source file lines in difference list form. This matches the form +/// used within metadata, which saves space by exploiting the fact that the +/// lines list is sorted and individual lines are usually not that long. +/// +/// We read it directly from metadata and only decode it into `Lines` form +/// when necessary. This is a significant performance win, especially for +/// small crates where very little of `std`'s metadata is used. +#[derive(Clone)] +pub struct SourceFileDiffs { + /// Position of the first line. Note that this is always encoded as a + /// `BytePos` because it is often much larger than any of the + /// differences. + line_start: BytePos, + + /// Always 1, 2, or 4. Always as small as possible, while being big + /// enough to hold the length of the longest line in the source file. + /// The 1 case is by far the most common. + bytes_per_diff: usize, + + /// The number of diffs encoded in `raw_diffs`. Always one less than + /// the number of lines in the source file. + num_diffs: usize, + + /// The diffs in "raw" form. Each segment of `bytes_per_diff` length + /// encodes one little-endian diff. Note that they aren't LEB128 + /// encoded. This makes for much faster decoding. Besides, the + /// bytes_per_diff==1 case is by far the most common, and LEB128 + /// encoding has no effect on that case. + raw_diffs: Vec<u8>, +} + +/// A single source in the [`SourceMap`]. +#[derive(Clone)] +pub struct SourceFile { + /// The name of the file that the source came from. Source that doesn't + /// originate from files has names between angle brackets by convention + /// (e.g., `<anon>`). + pub name: FileName, + /// The complete source code. + pub src: Option<Lrc<String>>, + /// The source code's hash. + pub src_hash: SourceFileHash, + /// The external source code (used for external crates, which will have a `None` + /// value as `self.src`. + pub external_src: Lock<ExternalSource>, + /// The start position of this source in the `SourceMap`. + pub start_pos: BytePos, + /// The end position of this source in the `SourceMap`. + pub end_pos: BytePos, + /// Locations of lines beginnings in the source code. + pub lines: Lock<SourceFileLines>, + /// Locations of multi-byte characters in the source code. + pub multibyte_chars: Vec<MultiByteChar>, + /// Width of characters that are not narrow in the source code. + pub non_narrow_chars: Vec<NonNarrowChar>, + /// Locations of characters removed during normalization. + pub normalized_pos: Vec<NormalizedPos>, + /// A hash of the filename, used for speeding up hashing in incremental compilation. + pub name_hash: u128, + /// Indicates which crate this `SourceFile` was imported from. + pub cnum: CrateNum, +} + +impl<S: Encoder> Encodable<S> for SourceFile { + fn encode(&self, s: &mut S) { + self.name.encode(s); + self.src_hash.encode(s); + self.start_pos.encode(s); + self.end_pos.encode(s); + + // We are always in `Lines` form by the time we reach here. + assert!(self.lines.borrow().is_lines()); + self.lines(|lines| { + // Store the length. + s.emit_u32(lines.len() as u32); + + // Compute and store the difference list. + if lines.len() != 0 { + let max_line_length = if lines.len() == 1 { + 0 + } else { + lines + .array_windows() + .map(|&[fst, snd]| snd - fst) + .map(|bp| bp.to_usize()) + .max() + .unwrap() + }; + + let bytes_per_diff: usize = match max_line_length { + 0..=0xFF => 1, + 0x100..=0xFFFF => 2, + _ => 4, + }; + + // Encode the number of bytes used per diff. + s.emit_u8(bytes_per_diff as u8); + + // Encode the first element. + lines[0].encode(s); + + // Encode the difference list. + let diff_iter = lines.array_windows().map(|&[fst, snd]| snd - fst); + let num_diffs = lines.len() - 1; + let mut raw_diffs; + match bytes_per_diff { + 1 => { + raw_diffs = Vec::with_capacity(num_diffs); + for diff in diff_iter { + raw_diffs.push(diff.0 as u8); + } + } + 2 => { + raw_diffs = Vec::with_capacity(bytes_per_diff * num_diffs); + for diff in diff_iter { + raw_diffs.extend_from_slice(&(diff.0 as u16).to_le_bytes()); + } + } + 4 => { + raw_diffs = Vec::with_capacity(bytes_per_diff * num_diffs); + for diff in diff_iter { + raw_diffs.extend_from_slice(&(diff.0 as u32).to_le_bytes()); + } + } + _ => unreachable!(), + } + s.emit_raw_bytes(&raw_diffs); + } + }); + + self.multibyte_chars.encode(s); + self.non_narrow_chars.encode(s); + self.name_hash.encode(s); + self.normalized_pos.encode(s); + self.cnum.encode(s); + } +} + +impl<D: Decoder> Decodable<D> for SourceFile { + fn decode(d: &mut D) -> SourceFile { + let name: FileName = Decodable::decode(d); + let src_hash: SourceFileHash = Decodable::decode(d); + let start_pos: BytePos = Decodable::decode(d); + let end_pos: BytePos = Decodable::decode(d); + let lines = { + let num_lines: u32 = Decodable::decode(d); + if num_lines > 0 { + // Read the number of bytes used per diff. + let bytes_per_diff = d.read_u8() as usize; + + // Read the first element. + let line_start: BytePos = Decodable::decode(d); + + // Read the difference list. + let num_diffs = num_lines as usize - 1; + let raw_diffs = d.read_raw_bytes(bytes_per_diff * num_diffs).to_vec(); + SourceFileLines::Diffs(SourceFileDiffs { + line_start, + bytes_per_diff, + num_diffs, + raw_diffs, + }) + } else { + SourceFileLines::Lines(vec![]) + } + }; + let multibyte_chars: Vec<MultiByteChar> = Decodable::decode(d); + let non_narrow_chars: Vec<NonNarrowChar> = Decodable::decode(d); + let name_hash: u128 = Decodable::decode(d); + let normalized_pos: Vec<NormalizedPos> = Decodable::decode(d); + let cnum: CrateNum = Decodable::decode(d); + SourceFile { + name, + start_pos, + end_pos, + src: None, + src_hash, + // Unused - the metadata decoder will construct + // a new SourceFile, filling in `external_src` properly + external_src: Lock::new(ExternalSource::Unneeded), + lines: Lock::new(lines), + multibyte_chars, + non_narrow_chars, + normalized_pos, + name_hash, + cnum, + } + } +} + +impl fmt::Debug for SourceFile { + fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(fmt, "SourceFile({:?})", self.name) + } +} + +impl SourceFile { + pub fn new( + name: FileName, + mut src: String, + start_pos: BytePos, + hash_kind: SourceFileHashAlgorithm, + ) -> Self { + // Compute the file hash before any normalization. + let src_hash = SourceFileHash::new(hash_kind, &src); + let normalized_pos = normalize_src(&mut src, start_pos); + + let name_hash = { + let mut hasher: StableHasher = StableHasher::new(); + name.hash(&mut hasher); + hasher.finish::<u128>() + }; + let end_pos = start_pos.to_usize() + src.len(); + assert!(end_pos <= u32::MAX as usize); + + let (lines, multibyte_chars, non_narrow_chars) = + analyze_source_file::analyze_source_file(&src, start_pos); + + SourceFile { + name, + src: Some(Lrc::new(src)), + src_hash, + external_src: Lock::new(ExternalSource::Unneeded), + start_pos, + end_pos: Pos::from_usize(end_pos), + lines: Lock::new(SourceFileLines::Lines(lines)), + multibyte_chars, + non_narrow_chars, + normalized_pos, + name_hash, + cnum: LOCAL_CRATE, + } + } + + pub fn lines<F, R>(&self, f: F) -> R + where + F: FnOnce(&[BytePos]) -> R, + { + let mut guard = self.lines.borrow_mut(); + match &*guard { + SourceFileLines::Lines(lines) => f(lines), + SourceFileLines::Diffs(SourceFileDiffs { + mut line_start, + bytes_per_diff, + num_diffs, + raw_diffs, + }) => { + // Convert from "diffs" form to "lines" form. + let num_lines = num_diffs + 1; + let mut lines = Vec::with_capacity(num_lines); + lines.push(line_start); + + assert_eq!(*num_diffs, raw_diffs.len() / bytes_per_diff); + match bytes_per_diff { + 1 => { + lines.extend(raw_diffs.into_iter().map(|&diff| { + line_start = line_start + BytePos(diff as u32); + line_start + })); + } + 2 => { + lines.extend((0..*num_diffs).map(|i| { + let pos = bytes_per_diff * i; + let bytes = [raw_diffs[pos], raw_diffs[pos + 1]]; + let diff = u16::from_le_bytes(bytes); + line_start = line_start + BytePos(diff as u32); + line_start + })); + } + 4 => { + lines.extend((0..*num_diffs).map(|i| { + let pos = bytes_per_diff * i; + let bytes = [ + raw_diffs[pos], + raw_diffs[pos + 1], + raw_diffs[pos + 2], + raw_diffs[pos + 3], + ]; + let diff = u32::from_le_bytes(bytes); + line_start = line_start + BytePos(diff); + line_start + })); + } + _ => unreachable!(), + } + let res = f(&lines); + *guard = SourceFileLines::Lines(lines); + res + } + } + } + + /// Returns the `BytePos` of the beginning of the current line. + pub fn line_begin_pos(&self, pos: BytePos) -> BytePos { + let line_index = self.lookup_line(pos).unwrap(); + self.lines(|lines| lines[line_index]) + } + + /// Add externally loaded source. + /// If the hash of the input doesn't match or no input is supplied via None, + /// it is interpreted as an error and the corresponding enum variant is set. + /// The return value signifies whether some kind of source is present. + pub fn add_external_src<F>(&self, get_src: F) -> bool + where + F: FnOnce() -> Option<String>, + { + if matches!( + *self.external_src.borrow(), + ExternalSource::Foreign { kind: ExternalSourceKind::AbsentOk, .. } + ) { + let src = get_src(); + let mut external_src = self.external_src.borrow_mut(); + // Check that no-one else have provided the source while we were getting it + if let ExternalSource::Foreign { + kind: src_kind @ ExternalSourceKind::AbsentOk, .. + } = &mut *external_src + { + if let Some(mut src) = src { + // The src_hash needs to be computed on the pre-normalized src. + if self.src_hash.matches(&src) { + normalize_src(&mut src, BytePos::from_usize(0)); + *src_kind = ExternalSourceKind::Present(Lrc::new(src)); + return true; + } + } else { + *src_kind = ExternalSourceKind::AbsentErr; + } + + false + } else { + self.src.is_some() || external_src.get_source().is_some() + } + } else { + self.src.is_some() || self.external_src.borrow().get_source().is_some() + } + } + + /// Gets a line from the list of pre-computed line-beginnings. + /// The line number here is 0-based. + pub fn get_line(&self, line_number: usize) -> Option<Cow<'_, str>> { + fn get_until_newline(src: &str, begin: usize) -> &str { + // We can't use `lines.get(line_number+1)` because we might + // be parsing when we call this function and thus the current + // line is the last one we have line info for. + let slice = &src[begin..]; + match slice.find('\n') { + Some(e) => &slice[..e], + None => slice, + } + } + + let begin = { + let line = self.lines(|lines| lines.get(line_number).copied())?; + let begin: BytePos = line - self.start_pos; + begin.to_usize() + }; + + if let Some(ref src) = self.src { + Some(Cow::from(get_until_newline(src, begin))) + } else if let Some(src) = self.external_src.borrow().get_source() { + Some(Cow::Owned(String::from(get_until_newline(src, begin)))) + } else { + None + } + } + + pub fn is_real_file(&self) -> bool { + self.name.is_real() + } + + #[inline] + pub fn is_imported(&self) -> bool { + self.src.is_none() + } + + pub fn count_lines(&self) -> usize { + self.lines(|lines| lines.len()) + } + + /// Finds the line containing the given position. The return value is the + /// index into the `lines` array of this `SourceFile`, not the 1-based line + /// number. If the source_file is empty or the position is located before the + /// first line, `None` is returned. + pub fn lookup_line(&self, pos: BytePos) -> Option<usize> { + self.lines(|lines| match lines.binary_search(&pos) { + Ok(idx) => Some(idx), + Err(0) => None, + Err(idx) => Some(idx - 1), + }) + } + + pub fn line_bounds(&self, line_index: usize) -> Range<BytePos> { + if self.is_empty() { + return self.start_pos..self.end_pos; + } + + self.lines(|lines| { + assert!(line_index < lines.len()); + if line_index == (lines.len() - 1) { + lines[line_index]..self.end_pos + } else { + lines[line_index]..lines[line_index + 1] + } + }) + } + + /// Returns whether or not the file contains the given `SourceMap` byte + /// position. The position one past the end of the file is considered to be + /// contained by the file. This implies that files for which `is_empty` + /// returns true still contain one byte position according to this function. + #[inline] + pub fn contains(&self, byte_pos: BytePos) -> bool { + byte_pos >= self.start_pos && byte_pos <= self.end_pos + } + + #[inline] + pub fn is_empty(&self) -> bool { + self.start_pos == self.end_pos + } + + /// Calculates the original byte position relative to the start of the file + /// based on the given byte position. + pub fn original_relative_byte_pos(&self, pos: BytePos) -> BytePos { + // Diff before any records is 0. Otherwise use the previously recorded + // diff as that applies to the following characters until a new diff + // is recorded. + let diff = match self.normalized_pos.binary_search_by(|np| np.pos.cmp(&pos)) { + Ok(i) => self.normalized_pos[i].diff, + Err(i) if i == 0 => 0, + Err(i) => self.normalized_pos[i - 1].diff, + }; + + BytePos::from_u32(pos.0 - self.start_pos.0 + diff) + } + + /// Converts an absolute `BytePos` to a `CharPos` relative to the `SourceFile`. + pub fn bytepos_to_file_charpos(&self, bpos: BytePos) -> CharPos { + // The number of extra bytes due to multibyte chars in the `SourceFile`. + let mut total_extra_bytes = 0; + + for mbc in self.multibyte_chars.iter() { + debug!("{}-byte char at {:?}", mbc.bytes, mbc.pos); + if mbc.pos < bpos { + // Every character is at least one byte, so we only + // count the actual extra bytes. + total_extra_bytes += mbc.bytes as u32 - 1; + // We should never see a byte position in the middle of a + // character. + assert!(bpos.to_u32() >= mbc.pos.to_u32() + mbc.bytes as u32); + } else { + break; + } + } + + assert!(self.start_pos.to_u32() + total_extra_bytes <= bpos.to_u32()); + CharPos(bpos.to_usize() - self.start_pos.to_usize() - total_extra_bytes as usize) + } + + /// Looks up the file's (1-based) line number and (0-based `CharPos`) column offset, for a + /// given `BytePos`. + pub fn lookup_file_pos(&self, pos: BytePos) -> (usize, CharPos) { + let chpos = self.bytepos_to_file_charpos(pos); + match self.lookup_line(pos) { + Some(a) => { + let line = a + 1; // Line numbers start at 1 + let linebpos = self.lines(|lines| lines[a]); + let linechpos = self.bytepos_to_file_charpos(linebpos); + let col = chpos - linechpos; + debug!("byte pos {:?} is on the line at byte pos {:?}", pos, linebpos); + debug!("char pos {:?} is on the line at char pos {:?}", chpos, linechpos); + debug!("byte is on line: {}", line); + assert!(chpos >= linechpos); + (line, col) + } + None => (0, chpos), + } + } + + /// Looks up the file's (1-based) line number, (0-based `CharPos`) column offset, and (0-based) + /// column offset when displayed, for a given `BytePos`. + pub fn lookup_file_pos_with_col_display(&self, pos: BytePos) -> (usize, CharPos, usize) { + let (line, col_or_chpos) = self.lookup_file_pos(pos); + if line > 0 { + let col = col_or_chpos; + let linebpos = self.lines(|lines| lines[line - 1]); + let col_display = { + let start_width_idx = self + .non_narrow_chars + .binary_search_by_key(&linebpos, |x| x.pos()) + .unwrap_or_else(|x| x); + let end_width_idx = self + .non_narrow_chars + .binary_search_by_key(&pos, |x| x.pos()) + .unwrap_or_else(|x| x); + let special_chars = end_width_idx - start_width_idx; + let non_narrow: usize = self.non_narrow_chars[start_width_idx..end_width_idx] + .iter() + .map(|x| x.width()) + .sum(); + col.0 - special_chars + non_narrow + }; + (line, col, col_display) + } else { + let chpos = col_or_chpos; + let col_display = { + let end_width_idx = self + .non_narrow_chars + .binary_search_by_key(&pos, |x| x.pos()) + .unwrap_or_else(|x| x); + let non_narrow: usize = + self.non_narrow_chars[0..end_width_idx].iter().map(|x| x.width()).sum(); + chpos.0 - end_width_idx + non_narrow + }; + (0, chpos, col_display) + } + } +} + +/// Normalizes the source code and records the normalizations. +fn normalize_src(src: &mut String, start_pos: BytePos) -> Vec<NormalizedPos> { + let mut normalized_pos = vec![]; + remove_bom(src, &mut normalized_pos); + normalize_newlines(src, &mut normalized_pos); + + // Offset all the positions by start_pos to match the final file positions. + for np in &mut normalized_pos { + np.pos.0 += start_pos.0; + } + + normalized_pos +} + +/// Removes UTF-8 BOM, if any. +fn remove_bom(src: &mut String, normalized_pos: &mut Vec<NormalizedPos>) { + if src.starts_with('\u{feff}') { + src.drain(..3); + normalized_pos.push(NormalizedPos { pos: BytePos(0), diff: 3 }); + } +} + +/// Replaces `\r\n` with `\n` in-place in `src`. +/// +/// Returns error if there's a lone `\r` in the string. +fn normalize_newlines(src: &mut String, normalized_pos: &mut Vec<NormalizedPos>) { + if !src.as_bytes().contains(&b'\r') { + return; + } + + // We replace `\r\n` with `\n` in-place, which doesn't break utf-8 encoding. + // While we *can* call `as_mut_vec` and do surgery on the live string + // directly, let's rather steal the contents of `src`. This makes the code + // safe even if a panic occurs. + + let mut buf = std::mem::replace(src, String::new()).into_bytes(); + let mut gap_len = 0; + let mut tail = buf.as_mut_slice(); + let mut cursor = 0; + let original_gap = normalized_pos.last().map_or(0, |l| l.diff); + loop { + let idx = match find_crlf(&tail[gap_len..]) { + None => tail.len(), + Some(idx) => idx + gap_len, + }; + tail.copy_within(gap_len..idx, 0); + tail = &mut tail[idx - gap_len..]; + if tail.len() == gap_len { + break; + } + cursor += idx - gap_len; + gap_len += 1; + normalized_pos.push(NormalizedPos { + pos: BytePos::from_usize(cursor + 1), + diff: original_gap + gap_len as u32, + }); + } + + // Account for removed `\r`. + // After `set_len`, `buf` is guaranteed to contain utf-8 again. + let new_len = buf.len() - gap_len; + unsafe { + buf.set_len(new_len); + *src = String::from_utf8_unchecked(buf); + } + + fn find_crlf(src: &[u8]) -> Option<usize> { + let mut search_idx = 0; + while let Some(idx) = find_cr(&src[search_idx..]) { + if src[search_idx..].get(idx + 1) != Some(&b'\n') { + search_idx += idx + 1; + continue; + } + return Some(search_idx + idx); + } + None + } + + fn find_cr(src: &[u8]) -> Option<usize> { + src.iter().position(|&b| b == b'\r') + } +} + +// _____________________________________________________________________________ +// Pos, BytePos, CharPos +// + +pub trait Pos { + fn from_usize(n: usize) -> Self; + fn to_usize(&self) -> usize; + fn from_u32(n: u32) -> Self; + fn to_u32(&self) -> u32; +} + +macro_rules! impl_pos { + ( + $( + $(#[$attr:meta])* + $vis:vis struct $ident:ident($inner_vis:vis $inner_ty:ty); + )* + ) => { + $( + $(#[$attr])* + $vis struct $ident($inner_vis $inner_ty); + + impl Pos for $ident { + #[inline(always)] + fn from_usize(n: usize) -> $ident { + $ident(n as $inner_ty) + } + + #[inline(always)] + fn to_usize(&self) -> usize { + self.0 as usize + } + + #[inline(always)] + fn from_u32(n: u32) -> $ident { + $ident(n as $inner_ty) + } + + #[inline(always)] + fn to_u32(&self) -> u32 { + self.0 as u32 + } + } + + impl Add for $ident { + type Output = $ident; + + #[inline(always)] + fn add(self, rhs: $ident) -> $ident { + $ident(self.0 + rhs.0) + } + } + + impl Sub for $ident { + type Output = $ident; + + #[inline(always)] + fn sub(self, rhs: $ident) -> $ident { + $ident(self.0 - rhs.0) + } + } + )* + }; +} + +impl_pos! { + /// A byte offset. + /// + /// Keep this small (currently 32-bits), as AST contains a lot of them. + #[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)] + pub struct BytePos(pub u32); + + /// A character offset. + /// + /// Because of multibyte UTF-8 characters, a byte offset + /// is not equivalent to a character offset. The [`SourceMap`] will convert [`BytePos`] + /// values to `CharPos` values as necessary. + #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug)] + pub struct CharPos(pub usize); +} + +impl<S: Encoder> Encodable<S> for BytePos { + fn encode(&self, s: &mut S) { + s.emit_u32(self.0); + } +} + +impl<D: Decoder> Decodable<D> for BytePos { + fn decode(d: &mut D) -> BytePos { + BytePos(d.read_u32()) + } +} + +// _____________________________________________________________________________ +// Loc, SourceFileAndLine, SourceFileAndBytePos +// + +/// A source code location used for error reporting. +#[derive(Debug, Clone)] +pub struct Loc { + /// Information about the original source. + pub file: Lrc<SourceFile>, + /// The (1-based) line number. + pub line: usize, + /// The (0-based) column offset. + pub col: CharPos, + /// The (0-based) column offset when displayed. + pub col_display: usize, +} + +// Used to be structural records. +#[derive(Debug)] +pub struct SourceFileAndLine { + pub sf: Lrc<SourceFile>, + /// Index of line, starting from 0. + pub line: usize, +} +#[derive(Debug)] +pub struct SourceFileAndBytePos { + pub sf: Lrc<SourceFile>, + pub pos: BytePos, +} + +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +pub struct LineInfo { + /// Index of line, starting from 0. + pub line_index: usize, + + /// Column in line where span begins, starting from 0. + pub start_col: CharPos, + + /// Column in line where span ends, starting from 0, exclusive. + pub end_col: CharPos, +} + +pub struct FileLines { + pub file: Lrc<SourceFile>, + pub lines: Vec<LineInfo>, +} + +pub static SPAN_TRACK: AtomicRef<fn(LocalDefId)> = AtomicRef::new(&((|_| {}) as fn(_))); + +// _____________________________________________________________________________ +// SpanLinesError, SpanSnippetError, DistinctSources, MalformedSourceMapPositions +// + +pub type FileLinesResult = Result<FileLines, SpanLinesError>; + +#[derive(Clone, PartialEq, Eq, Debug)] +pub enum SpanLinesError { + DistinctSources(DistinctSources), +} + +#[derive(Clone, PartialEq, Eq, Debug)] +pub enum SpanSnippetError { + IllFormedSpan(Span), + DistinctSources(DistinctSources), + MalformedForSourcemap(MalformedSourceMapPositions), + SourceNotAvailable { filename: FileName }, +} + +#[derive(Clone, PartialEq, Eq, Debug)] +pub struct DistinctSources { + pub begin: (FileName, BytePos), + pub end: (FileName, BytePos), +} + +#[derive(Clone, PartialEq, Eq, Debug)] +pub struct MalformedSourceMapPositions { + pub name: FileName, + pub source_len: usize, + pub begin_pos: BytePos, + pub end_pos: BytePos, +} + +/// Range inside of a `Span` used for diagnostics when we only have access to relative positions. +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +pub struct InnerSpan { + pub start: usize, + pub end: usize, +} + +impl InnerSpan { + pub fn new(start: usize, end: usize) -> InnerSpan { + InnerSpan { start, end } + } +} + +/// Requirements for a `StableHashingContext` to be used in this crate. +/// +/// This is a hack to allow using the [`HashStable_Generic`] derive macro +/// instead of implementing everything in rustc_middle. +pub trait HashStableContext { + fn def_path_hash(&self, def_id: DefId) -> DefPathHash; + fn hash_spans(&self) -> bool; + /// Accesses `sess.opts.unstable_opts.incremental_ignore_spans` since + /// we don't have easy access to a `Session` + fn unstable_opts_incremental_ignore_spans(&self) -> bool; + fn def_span(&self, def_id: LocalDefId) -> Span; + fn span_data_to_lines_and_cols( + &mut self, + span: &SpanData, + ) -> Option<(Lrc<SourceFile>, usize, BytePos, usize, BytePos)>; + fn hashing_controls(&self) -> HashingControls; +} + +impl<CTX> HashStable<CTX> for Span +where + CTX: HashStableContext, +{ + /// Hashes a span in a stable way. We can't directly hash the span's `BytePos` + /// fields (that would be similar to hashing pointers, since those are just + /// offsets into the `SourceMap`). Instead, we hash the (file name, line, column) + /// triple, which stays the same even if the containing `SourceFile` has moved + /// within the `SourceMap`. + /// + /// Also note that we are hashing byte offsets for the column, not unicode + /// codepoint offsets. For the purpose of the hash that's sufficient. + /// Also, hashing filenames is expensive so we avoid doing it twice when the + /// span starts and ends in the same file, which is almost always the case. + fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) { + const TAG_VALID_SPAN: u8 = 0; + const TAG_INVALID_SPAN: u8 = 1; + const TAG_RELATIVE_SPAN: u8 = 2; + + if !ctx.hash_spans() { + return; + } + + let span = self.data_untracked(); + span.ctxt.hash_stable(ctx, hasher); + span.parent.hash_stable(ctx, hasher); + + if span.is_dummy() { + Hash::hash(&TAG_INVALID_SPAN, hasher); + return; + } + + if let Some(parent) = span.parent { + let def_span = ctx.def_span(parent).data_untracked(); + if def_span.contains(span) { + // This span is enclosed in a definition: only hash the relative position. + Hash::hash(&TAG_RELATIVE_SPAN, hasher); + (span.lo - def_span.lo).to_u32().hash_stable(ctx, hasher); + (span.hi - def_span.lo).to_u32().hash_stable(ctx, hasher); + return; + } + } + + // If this is not an empty or invalid span, we want to hash the last + // position that belongs to it, as opposed to hashing the first + // position past it. + let Some((file, line_lo, col_lo, line_hi, col_hi)) = ctx.span_data_to_lines_and_cols(&span) else { + Hash::hash(&TAG_INVALID_SPAN, hasher); + return; + }; + + Hash::hash(&TAG_VALID_SPAN, hasher); + // We truncate the stable ID hash and line and column numbers. The chances + // of causing a collision this way should be minimal. + Hash::hash(&(file.name_hash as u64), hasher); + + // Hash both the length and the end location (line/column) of a span. If we + // hash only the length, for example, then two otherwise equal spans with + // different end locations will have the same hash. This can cause a problem + // during incremental compilation wherein a previous result for a query that + // depends on the end location of a span will be incorrectly reused when the + // end location of the span it depends on has changed (see issue #74890). A + // similar analysis applies if some query depends specifically on the length + // of the span, but we only hash the end location. So hash both. + + let col_lo_trunc = (col_lo.0 as u64) & 0xFF; + let line_lo_trunc = ((line_lo as u64) & 0xFF_FF_FF) << 8; + let col_hi_trunc = (col_hi.0 as u64) & 0xFF << 32; + let line_hi_trunc = ((line_hi as u64) & 0xFF_FF_FF) << 40; + let col_line = col_lo_trunc | line_lo_trunc | col_hi_trunc | line_hi_trunc; + let len = (span.hi - span.lo).0; + Hash::hash(&col_line, hasher); + Hash::hash(&len, hasher); + } +} |