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Diffstat (limited to 'compiler/rustc_span/src/lib.rs')
| -rw-r--r-- | compiler/rustc_span/src/lib.rs | 1872 |
1 files changed, 1872 insertions, 0 deletions
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs new file mode 100644 index 00000000000..c654dade2ab --- /dev/null +++ b/compiler/rustc_span/src/lib.rs @@ -0,0 +1,1872 @@ +//! The source positions and related helper functions. +//! +//! ## Note +//! +//! This API is completely unstable and subject to change. + +#![doc(html_root_url = "https://doc.rust-lang.org/nightly/")] +#![feature(crate_visibility_modifier)] +#![feature(const_fn)] +#![feature(const_panic)] +#![feature(negative_impls)] +#![feature(nll)] +#![feature(optin_builtin_traits)] +#![feature(min_specialization)] +#![feature(option_expect_none)] +#![feature(refcell_take)] + +#[macro_use] +extern crate rustc_macros; + +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; +pub use hygiene::SyntaxContext; +use hygiene::Transparency; +pub use hygiene::{DesugaringKind, ExpnData, ExpnId, ExpnKind, ForLoopLoc, MacroKind}; +pub mod def_id; +use def_id::{CrateNum, DefId, LOCAL_CRATE}; +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; + +use rustc_data_structures::fingerprint::Fingerprint; +use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; +use rustc_data_structures::sync::{Lock, Lrc}; + +use std::borrow::Cow; +use std::cell::RefCell; +use std::cmp::{self, Ordering}; +use std::fmt; +use std::hash::Hash; +use std::ops::{Add, Sub}; +use std::path::{Path, PathBuf}; +use std::str::FromStr; + +use md5::Md5; +use sha1::Digest; +use sha1::Sha1; + +#[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: Lock<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: Lock::new(symbol::Interner::fresh()), + span_interner: Lock::new(span_encoding::SpanInterner::default()), + hygiene_data: Lock::new(hygiene::HygieneData::new(edition)), + source_map: Lock::new(None), + } + } +} + +pub fn with_session_globals<R>(edition: Edition, f: impl FnOnce() -> R) -> R { + let session_globals = SessionGlobals::new(edition); + SESSION_GLOBALS.set(&session_globals, f) +} + +pub fn with_default_session_globals<R>(f: impl FnOnce() -> R) -> R { + with_session_globals(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!(pub static SESSION_GLOBALS: SessionGlobals); + +// FIXME: Perhaps this should not implement Rustc{Decodable, Encodable} +// +// 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, Hash)] +#[derive(HashStable_Generic, Decodable, Encodable)] +pub enum RealFileName { + Named(PathBuf), + /// For de-virtualized paths (namely paths into libstd that have been mapped + /// to the appropriate spot on the local host's file system), + Devirtualized { + /// `local_path` is the (host-dependent) local path to the file. + local_path: PathBuf, + /// `virtual_name` is the stable path rustc will store internally within + /// build artifacts. + virtual_name: PathBuf, + }, +} + +impl RealFileName { + /// Returns the path suitable for reading from the file system on the local host. + /// Avoid embedding this in build artifacts; see `stable_name` for that. + pub fn local_path(&self) -> &Path { + match self { + RealFileName::Named(p) + | RealFileName::Devirtualized { local_path: p, virtual_name: _ } => &p, + } + } + + /// Returns the path suitable for reading from the file system on the local host. + /// Avoid embedding this in build artifacts; see `stable_name` for that. + pub fn into_local_path(self) -> PathBuf { + match self { + RealFileName::Named(p) + | RealFileName::Devirtualized { local_path: p, virtual_name: _ } => p, + } + } + + /// Returns the path suitable for embedding into build artifacts. Note that + /// a virtualized path will not correspond to a valid file system path; see + /// `local_path` for something that is more likely to return paths into the + /// local host file system. + pub fn stable_name(&self) -> &Path { + match self { + RealFileName::Named(p) + | RealFileName::Devirtualized { local_path: _, virtual_name: p } => &p, + } + } +} + +/// Differentiates between real files and common virtual files. +#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash)] +#[derive(HashStable_Generic, 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 std::fmt::Display for FileName { + fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + use FileName::*; + match *self { + Real(RealFileName::Named(ref path)) => write!(fmt, "{}", path.display()), + // FIXME: might be nice to display both compoments of Devirtualized. + // But for now (to backport fix for issue #70924), best to not + // perturb diagnostics so its obvious test suite still works. + Real(RealFileName::Devirtualized { ref local_path, virtual_name: _ }) => { + write!(fmt, "{}", local_path.display()) + } + 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 From<PathBuf> for FileName { + fn from(p: PathBuf) -> Self { + assert!(!p.to_string_lossy().ends_with('>')); + FileName::Real(RealFileName::Named(p)) + } +} + +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 quote_expansion_source_code(src: &str) -> FileName { + let mut hasher = StableHasher::new(); + src.hash(&mut hasher); + FileName::QuoteExpansion(hasher.finish()) + } + + 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()) + } +} + +/// Spans represent a region of code, used for error reporting. Positions in spans +/// are *absolute* positions from the beginning of the source_map, 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 - 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 = hi - 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, Ord, PartialOrd)] +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, +} + +impl SpanData { + #[inline] + pub fn with_lo(&self, lo: BytePos) -> Span { + Span::new(lo, self.hi, self.ctxt) + } + #[inline] + pub fn with_hi(&self, hi: BytePos) -> Span { + Span::new(self.lo, hi, self.ctxt) + } + #[inline] + pub fn with_ctxt(&self, ctxt: SyntaxContext) -> Span { + Span::new(self.lo, self.hi, ctxt) + } +} + +// 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()) + } +} + +/// A collection of `Span`s. +/// +/// Spans have two orthogonal attributes: +/// +/// - They can be *primary spans*. In this case they are the locus of +/// the error, and would be rendered with `^^^`. +/// - They can have a *label*. In this case, the label is written next +/// to the mark in the snippet when we render. +#[derive(Clone, Debug, Hash, PartialEq, Eq, Encodable, Decodable)] +pub struct MultiSpan { + primary_spans: Vec<Span>, + span_labels: Vec<(Span, String)>, +} + +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().ctxt + } + #[inline] + pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span { + self.data().with_ctxt(ctxt) + } + + /// Returns `true` if this is a dummy span with any hygienic context. + #[inline] + pub fn is_dummy(self) -> bool { + let span = self.data(); + span.lo.0 == 0 && span.hi.0 == 0 + } + + /// 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, _)) + } + + #[inline] + pub fn with_root_ctxt(lo: BytePos, hi: BytePos) -> Span { + Span::new(lo, hi, SyntaxContext::root()) + } + + /// 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(); + 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(); + span.with_lo(span.hi) + } + + /// 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.lo <= other.lo && other.hi <= span.hi + } + + /// 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(self) -> Option<Span> { + let expn_data = self.ctxt().outer_expn_data(); + if !expn_data.is_root() { Some(expn_data.call_site) } else { None } + } + + /// Edition of the crate from which this span came. + pub fn edition(self) -> edition::Edition { + self.ctxt().outer_expn_data().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 + } + + /// 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 || f == sym::allow_internal_unstable_backcompat_hack) + }) + } + + /// 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`. + 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 }, + ) + } + + /// Returns a `Span` between the end of `self` to the beginning of `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 }, + ) + } + + /// Returns a `Span` between the beginning of `self` to the beginning of `end`. + pub fn until(self, end: Span) -> Span { + let span = self.data(); + let end = end.data(); + Span::new( + span.lo, + end.lo, + if end.ctxt == SyntaxContext::root() { end.ctxt } else { span.ctxt }, + ) + } + + 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, + ) + } + + /// 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); + 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); + 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); + 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); + 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); + 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()) + } +} + +#[derive(Clone, Debug)] +pub struct SpanLabel { + /// The span we are going to include in the final snippet. + pub span: Span, + + /// Is this a primary span? This is the "locus" of the message, + /// and is indicated with a `^^^^` underline, versus `----`. + pub is_primary: bool, + + /// What label should we attach to this span (if any)? + pub label: Option<String>, +} + +impl Default for Span { + fn default() -> Self { + DUMMY_SP + } +} + +impl<E: Encoder> Encodable<E> for Span { + default fn encode(&self, s: &mut E) -> Result<(), E::Error> { + let span = self.data(); + s.emit_struct("Span", 2, |s| { + s.emit_struct_field("lo", 0, |s| span.lo.encode(s))?; + s.emit_struct_field("hi", 1, |s| span.hi.encode(s)) + }) + } +} +impl<D: Decoder> Decodable<D> for Span { + default fn decode(s: &mut D) -> Result<Span, D::Error> { + s.read_struct("Span", 2, |d| { + let lo = d.read_struct_field("lo", 0, Decodable::decode)?; + let hi = d.read_struct_field("hi", 1, Decodable::decode)?; + + Ok(Span::new(lo, hi, SyntaxContext::root())) + }) + } +} + +/// Calls the provided closure, using the provided `SourceMap` to format +/// any spans that are debug-printed during the closure'e exectuino. +/// +/// 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 { + SESSION_GLOBALS.with(|session_globals| { + *session_globals.source_map.borrow_mut() = Some(source_map); + }); + struct ClearSourceMap; + impl Drop for ClearSourceMap { + fn drop(&mut self) { + SESSION_GLOBALS.with(|session_globals| { + session_globals.source_map.borrow_mut().take(); + }); + } + } + + let _guard = ClearSourceMap; + f() +} + +pub fn debug_with_source_map( + span: Span, + f: &mut fmt::Formatter<'_>, + source_map: &SourceMap, +) -> fmt::Result { + write!(f, "{} ({:?})", source_map.span_to_string(span), span.ctxt()) +} + +pub fn default_span_debug(span: Span, f: &mut fmt::Formatter<'_>) -> fmt::Result { + SESSION_GLOBALS.with(|session_globals| { + if let Some(source_map) = &*session_globals.source_map.borrow() { + debug_with_source_map(span, f, source_map) + } else { + f.debug_struct("Span") + .field("lo", &span.lo()) + .field("hi", &span.hi()) + .field("ctxt", &span.ctxt()) + .finish() + } + }) +} + +impl fmt::Debug for Span { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + (*SPAN_DEBUG)(*self, f) + } +} + +impl fmt::Debug for SpanData { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + (*SPAN_DEBUG)(Span::new(self.lo, self.hi, self.ctxt), f) + } +} + +impl MultiSpan { + #[inline] + pub fn new() -> MultiSpan { + MultiSpan { primary_spans: vec![], span_labels: vec![] } + } + + pub fn from_span(primary_span: Span) -> MultiSpan { + MultiSpan { primary_spans: vec![primary_span], span_labels: vec![] } + } + + pub fn from_spans(mut vec: Vec<Span>) -> MultiSpan { + vec.sort(); + MultiSpan { primary_spans: vec, span_labels: vec![] } + } + + pub fn push_span_label(&mut self, span: Span, label: String) { + self.span_labels.push((span, label)); + } + + /// Selects the first primary span (if any). + pub fn primary_span(&self) -> Option<Span> { + self.primary_spans.first().cloned() + } + + /// Returns all primary spans. + pub fn primary_spans(&self) -> &[Span] { + &self.primary_spans + } + + /// Returns `true` if any of the primary spans are displayable. + pub fn has_primary_spans(&self) -> bool { + self.primary_spans.iter().any(|sp| !sp.is_dummy()) + } + + /// Returns `true` if this contains only a dummy primary span with any hygienic context. + pub fn is_dummy(&self) -> bool { + let mut is_dummy = true; + for span in &self.primary_spans { + if !span.is_dummy() { + is_dummy = false; + } + } + is_dummy + } + + /// Replaces all occurrences of one Span with another. Used to move `Span`s in areas that don't + /// display well (like std macros). Returns whether replacements occurred. + pub fn replace(&mut self, before: Span, after: Span) -> bool { + let mut replacements_occurred = false; + for primary_span in &mut self.primary_spans { + if *primary_span == before { + *primary_span = after; + replacements_occurred = true; + } + } + for span_label in &mut self.span_labels { + if span_label.0 == before { + span_label.0 = after; + replacements_occurred = true; + } + } + replacements_occurred + } + + /// Returns the strings to highlight. We always ensure that there + /// is an entry for each of the primary spans -- for each primary + /// span `P`, if there is at least one label with span `P`, we return + /// those labels (marked as primary). But otherwise we return + /// `SpanLabel` instances with empty labels. + pub fn span_labels(&self) -> Vec<SpanLabel> { + let is_primary = |span| self.primary_spans.contains(&span); + + let mut span_labels = self + .span_labels + .iter() + .map(|&(span, ref label)| SpanLabel { + span, + is_primary: is_primary(span), + label: Some(label.clone()), + }) + .collect::<Vec<_>>(); + + for &span in &self.primary_spans { + if !span_labels.iter().any(|sl| sl.span == span) { + span_labels.push(SpanLabel { span, is_primary: true, label: None }); + } + } + + span_labels + } + + /// Returns `true` if any of the span labels is displayable. + pub fn has_span_labels(&self) -> bool { + self.span_labels.iter().any(|(sp, _)| !sp.is_dummy()) + } +} + +impl From<Span> for MultiSpan { + fn from(span: Span) -> MultiSpan { + MultiSpan::from_span(span) + } +} + +impl From<Vec<Span>> for MultiSpan { + fn from(spans: Vec<Span>) -> MultiSpan { + MultiSpan::from_spans(spans) + } +} + +/// 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 is_absent(&self) -> bool { + match self { + ExternalSource::Foreign { kind: ExternalSourceKind::Present(_), .. } => false, + _ => true, + } + } + + 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)] +pub enum SourceFileHashAlgorithm { + Md5, + Sha1, +} + +impl FromStr for SourceFileHashAlgorithm { + type Err = (); + + fn from_str(s: &str) -> Result<SourceFileHashAlgorithm, ()> { + match s { + "md5" => Ok(SourceFileHashAlgorithm::Md5), + "sha1" => Ok(SourceFileHashAlgorithm::Sha1), + _ => Err(()), + } + } +} + +rustc_data_structures::impl_stable_hash_via_hash!(SourceFileHashAlgorithm); + +/// The hash of the on-disk source file used for debug info. +#[derive(Copy, Clone, PartialEq, Eq, Debug)] +#[derive(HashStable_Generic, Encodable, Decodable)] +pub struct SourceFileHash { + pub kind: SourceFileHashAlgorithm, + value: [u8; 20], +} + +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)); + } + } + 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, + } + } +} + +/// 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, + /// `true` if the `name` field above has been modified by `--remap-path-prefix`. + pub name_was_remapped: bool, + /// The unmapped path of the file that the source came from. + /// Set to `None` if the `SourceFile` was imported from an external crate. + pub unmapped_path: Option<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: Vec<BytePos>, + /// 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) -> Result<(), S::Error> { + s.emit_struct("SourceFile", 8, |s| { + s.emit_struct_field("name", 0, |s| self.name.encode(s))?; + s.emit_struct_field("name_was_remapped", 1, |s| self.name_was_remapped.encode(s))?; + s.emit_struct_field("src_hash", 2, |s| self.src_hash.encode(s))?; + s.emit_struct_field("start_pos", 3, |s| self.start_pos.encode(s))?; + s.emit_struct_field("end_pos", 4, |s| self.end_pos.encode(s))?; + s.emit_struct_field("lines", 5, |s| { + let lines = &self.lines[..]; + // Store the length. + s.emit_u32(lines.len() as u32)?; + + if !lines.is_empty() { + // In order to preserve some space, we exploit the fact that + // the lines list is sorted and individual lines are + // probably not that long. Because of that we can store lines + // as a difference list, using as little space as possible + // for the differences. + let max_line_length = if lines.len() == 1 { + 0 + } else { + lines.windows(2).map(|w| w[1] - w[0]).map(|bp| bp.to_usize()).max().unwrap() + }; + + let bytes_per_diff: u8 = match max_line_length { + 0..=0xFF => 1, + 0x100..=0xFFFF => 2, + _ => 4, + }; + + // Encode the number of bytes used per diff. + bytes_per_diff.encode(s)?; + + // Encode the first element. + lines[0].encode(s)?; + + let diff_iter = (&lines[..]).windows(2).map(|w| (w[1] - w[0])); + + match bytes_per_diff { + 1 => { + for diff in diff_iter { + (diff.0 as u8).encode(s)? + } + } + 2 => { + for diff in diff_iter { + (diff.0 as u16).encode(s)? + } + } + 4 => { + for diff in diff_iter { + diff.0.encode(s)? + } + } + _ => unreachable!(), + } + } + + Ok(()) + })?; + s.emit_struct_field("multibyte_chars", 6, |s| self.multibyte_chars.encode(s))?; + s.emit_struct_field("non_narrow_chars", 7, |s| self.non_narrow_chars.encode(s))?; + s.emit_struct_field("name_hash", 8, |s| self.name_hash.encode(s))?; + s.emit_struct_field("normalized_pos", 9, |s| self.normalized_pos.encode(s))?; + s.emit_struct_field("cnum", 10, |s| self.cnum.encode(s)) + }) + } +} + +impl<D: Decoder> Decodable<D> for SourceFile { + fn decode(d: &mut D) -> Result<SourceFile, D::Error> { + d.read_struct("SourceFile", 8, |d| { + let name: FileName = d.read_struct_field("name", 0, |d| Decodable::decode(d))?; + let name_was_remapped: bool = + d.read_struct_field("name_was_remapped", 1, |d| Decodable::decode(d))?; + let src_hash: SourceFileHash = + d.read_struct_field("src_hash", 2, |d| Decodable::decode(d))?; + let start_pos: BytePos = + d.read_struct_field("start_pos", 3, |d| Decodable::decode(d))?; + let end_pos: BytePos = d.read_struct_field("end_pos", 4, |d| Decodable::decode(d))?; + let lines: Vec<BytePos> = d.read_struct_field("lines", 5, |d| { + let num_lines: u32 = Decodable::decode(d)?; + let mut lines = Vec::with_capacity(num_lines as usize); + + if num_lines > 0 { + // Read the number of bytes used per diff. + let bytes_per_diff: u8 = Decodable::decode(d)?; + + // Read the first element. + let mut line_start: BytePos = Decodable::decode(d)?; + lines.push(line_start); + + for _ in 1..num_lines { + let diff = match bytes_per_diff { + 1 => d.read_u8()? as u32, + 2 => d.read_u16()? as u32, + 4 => d.read_u32()?, + _ => unreachable!(), + }; + + line_start = line_start + BytePos(diff); + + lines.push(line_start); + } + } + + Ok(lines) + })?; + let multibyte_chars: Vec<MultiByteChar> = + d.read_struct_field("multibyte_chars", 6, |d| Decodable::decode(d))?; + let non_narrow_chars: Vec<NonNarrowChar> = + d.read_struct_field("non_narrow_chars", 7, |d| Decodable::decode(d))?; + let name_hash: u128 = d.read_struct_field("name_hash", 8, |d| Decodable::decode(d))?; + let normalized_pos: Vec<NormalizedPos> = + d.read_struct_field("normalized_pos", 9, |d| Decodable::decode(d))?; + let cnum: CrateNum = d.read_struct_field("cnum", 10, |d| Decodable::decode(d))?; + Ok(SourceFile { + name, + name_was_remapped, + unmapped_path: None, + 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, + 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, + name_was_remapped: bool, + unmapped_path: 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, + name_was_remapped, + unmapped_path: Some(unmapped_path), + src: Some(Lrc::new(src)), + src_hash, + external_src: Lock::new(ExternalSource::Unneeded), + start_pos, + end_pos: Pos::from_usize(end_pos), + lines, + multibyte_chars, + non_narrow_chars, + normalized_pos, + name_hash, + cnum: LOCAL_CRATE, + } + } + + /// 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[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.get(line_number)?; + 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() + } + + pub fn is_imported(&self) -> bool { + self.src.is_none() + } + + pub fn byte_length(&self) -> u32 { + self.end_pos.0 - self.start_pos.0 + } + pub fn count_lines(&self) -> usize { + self.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> { + if self.lines.is_empty() { + return None; + } + + let line_index = lookup_line(&self.lines[..], pos); + assert!(line_index < self.lines.len() as isize); + if line_index >= 0 { Some(line_index as usize) } else { None } + } + + pub fn line_bounds(&self, line_index: usize) -> (BytePos, BytePos) { + if self.start_pos == self.end_pos { + return (self.start_pos, self.end_pos); + } + + assert!(line_index < self.lines.len()); + if line_index == (self.lines.len() - 1) { + (self.lines[line_index], self.end_pos) + } else { + (self.lines[line_index], self.lines[line_index + 1]) + } + } + + #[inline] + pub fn contains(&self, byte_pos: BytePos) -> bool { + byte_pos >= self.start_pos && byte_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) + } +} + +/// 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; +} + +/// 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(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)] +pub struct CharPos(pub usize); + +// FIXME: lots of boilerplate in these impls, but so far my attempts to fix +// have been unsuccessful. + +impl Pos for BytePos { + #[inline(always)] + fn from_usize(n: usize) -> BytePos { + BytePos(n as u32) + } + + #[inline(always)] + fn to_usize(&self) -> usize { + self.0 as usize + } + + #[inline(always)] + fn from_u32(n: u32) -> BytePos { + BytePos(n) + } + + #[inline(always)] + fn to_u32(&self) -> u32 { + self.0 + } +} + +impl Add for BytePos { + type Output = BytePos; + + #[inline(always)] + fn add(self, rhs: BytePos) -> BytePos { + BytePos((self.to_usize() + rhs.to_usize()) as u32) + } +} + +impl Sub for BytePos { + type Output = BytePos; + + #[inline(always)] + fn sub(self, rhs: BytePos) -> BytePos { + BytePos((self.to_usize() - rhs.to_usize()) as u32) + } +} + +impl<S: rustc_serialize::Encoder> Encodable<S> for BytePos { + fn encode(&self, s: &mut S) -> Result<(), S::Error> { + s.emit_u32(self.0) + } +} + +impl<D: rustc_serialize::Decoder> Decodable<D> for BytePos { + fn decode(d: &mut D) -> Result<BytePos, D::Error> { + Ok(BytePos(d.read_u32()?)) + } +} + +impl Pos for CharPos { + #[inline(always)] + fn from_usize(n: usize) -> CharPos { + CharPos(n) + } + + #[inline(always)] + fn to_usize(&self) -> usize { + self.0 + } + + #[inline(always)] + fn from_u32(n: u32) -> CharPos { + CharPos(n as usize) + } + + #[inline(always)] + fn to_u32(&self) -> u32 { + self.0 as u32 + } +} + +impl Add for CharPos { + type Output = CharPos; + + #[inline(always)] + fn add(self, rhs: CharPos) -> CharPos { + CharPos(self.to_usize() + rhs.to_usize()) + } +} + +impl Sub for CharPos { + type Output = CharPos; + + #[inline(always)] + fn sub(self, rhs: CharPos) -> CharPos { + CharPos(self.to_usize() - rhs.to_usize()) + } +} + +// _____________________________________________________________________________ +// 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>, + 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_DEBUG: AtomicRef<fn(Span, &mut fmt::Formatter<'_>) -> fmt::Result> = + AtomicRef::new(&(default_span_debug as fn(_, &mut fmt::Formatter<'_>) -> _)); + +// _____________________________________________________________________________ +// 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 } + } +} + +// Given a slice of line start positions and a position, returns the index of +// the line the position is on. Returns -1 if the position is located before +// the first line. +fn lookup_line(lines: &[BytePos], pos: BytePos) -> isize { + match lines.binary_search(&pos) { + Ok(line) => line as isize, + Err(line) => line as isize - 1, + } +} + +/// 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 librustc_middle. +pub trait HashStableContext { + fn hash_def_id(&mut self, _: DefId, hasher: &mut StableHasher); + fn hash_crate_num(&mut self, _: CrateNum, hasher: &mut StableHasher); + fn hash_spans(&self) -> bool; + fn byte_pos_to_line_and_col( + &mut self, + byte: BytePos, + ) -> Option<(Lrc<SourceFile>, usize, BytePos)>; +} + +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; + + if !ctx.hash_spans() { + return; + } + + if *self == DUMMY_SP { + std::hash::Hash::hash(&TAG_INVALID_SPAN, 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 span = self.data(); + let (file_lo, line_lo, col_lo) = match ctx.byte_pos_to_line_and_col(span.lo) { + Some(pos) => pos, + None => { + std::hash::Hash::hash(&TAG_INVALID_SPAN, hasher); + span.ctxt.hash_stable(ctx, hasher); + return; + } + }; + + if !file_lo.contains(span.hi) { + std::hash::Hash::hash(&TAG_INVALID_SPAN, hasher); + span.ctxt.hash_stable(ctx, hasher); + return; + } + + std::hash::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. + std::hash::Hash::hash(&(file_lo.name_hash as u64), hasher); + + let col = (col_lo.0 as u64) & 0xFF; + let line = ((line_lo as u64) & 0xFF_FF_FF) << 8; + let len = ((span.hi - span.lo).0 as u64) << 32; + let line_col_len = col | line | len; + std::hash::Hash::hash(&line_col_len, hasher); + span.ctxt.hash_stable(ctx, hasher); + } +} + +impl<CTX: HashStableContext> HashStable<CTX> for SyntaxContext { + fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) { + const TAG_EXPANSION: u8 = 0; + const TAG_NO_EXPANSION: u8 = 1; + + if *self == SyntaxContext::root() { + TAG_NO_EXPANSION.hash_stable(ctx, hasher); + } else { + TAG_EXPANSION.hash_stable(ctx, hasher); + let (expn_id, transparency) = self.outer_mark(); + expn_id.hash_stable(ctx, hasher); + transparency.hash_stable(ctx, hasher); + } + } +} + +impl<CTX: HashStableContext> HashStable<CTX> for ExpnId { + fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) { + // Since the same expansion context is usually referenced many + // times, we cache a stable hash of it and hash that instead of + // recursing every time. + thread_local! { + static CACHE: RefCell<Vec<Option<Fingerprint>>> = Default::default(); + } + + const TAG_ROOT: u8 = 0; + const TAG_NOT_ROOT: u8 = 1; + + if *self == ExpnId::root() { + TAG_ROOT.hash_stable(ctx, hasher); + return; + } + + TAG_NOT_ROOT.hash_stable(ctx, hasher); + let index = self.as_u32() as usize; + + let res = CACHE.with(|cache| cache.borrow().get(index).copied().flatten()); + + if let Some(res) = res { + res.hash_stable(ctx, hasher); + } else { + let new_len = index + 1; + + let mut sub_hasher = StableHasher::new(); + self.expn_data().hash_stable(ctx, &mut sub_hasher); + let sub_hash: Fingerprint = sub_hasher.finish(); + + CACHE.with(|cache| { + let mut cache = cache.borrow_mut(); + if cache.len() < new_len { + cache.resize(new_len, None); + } + cache[index].replace(sub_hash).expect_none("Cache slot was filled"); + }); + sub_hash.hash_stable(ctx, hasher); + } + } +} |