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Diffstat (limited to 'compiler/rustc_span/src/source_map.rs')
| -rw-r--r-- | compiler/rustc_span/src/source_map.rs | 1281 |
1 files changed, 1281 insertions, 0 deletions
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs new file mode 100644 index 000000000..28381157d --- /dev/null +++ b/compiler/rustc_span/src/source_map.rs @@ -0,0 +1,1281 @@ +//! Types for tracking pieces of source code within a crate. +//! +//! The [`SourceMap`] tracks all the source code used within a single crate, mapping +//! from integer byte positions to the original source code location. Each bit +//! of source parsed during crate parsing (typically files, in-memory strings, +//! or various bits of macro expansion) cover a continuous range of bytes in the +//! `SourceMap` and are represented by [`SourceFile`]s. Byte positions are stored in +//! [`Span`] and used pervasively in the compiler. They are absolute positions +//! within the `SourceMap`, which upon request can be converted to line and column +//! information, source code snippets, etc. + +pub use crate::hygiene::{ExpnData, ExpnKind}; +pub use crate::*; + +use rustc_data_structures::fx::FxHashMap; +use rustc_data_structures::stable_hasher::StableHasher; +use rustc_data_structures::sync::{AtomicU32, Lrc, MappedReadGuard, ReadGuard, RwLock}; +use std::hash::Hash; +use std::path::{Path, PathBuf}; +use std::sync::atomic::Ordering; +use std::{clone::Clone, cmp}; +use std::{convert::TryFrom, unreachable}; + +use std::fs; +use std::io; +use tracing::debug; + +#[cfg(test)] +mod tests; + +/// Returns the span itself if it doesn't come from a macro expansion, +/// otherwise return the call site span up to the `enclosing_sp` by +/// following the `expn_data` chain. +pub fn original_sp(sp: Span, enclosing_sp: Span) -> Span { + let expn_data1 = sp.ctxt().outer_expn_data(); + let expn_data2 = enclosing_sp.ctxt().outer_expn_data(); + if expn_data1.is_root() || !expn_data2.is_root() && expn_data1.call_site == expn_data2.call_site + { + sp + } else { + original_sp(expn_data1.call_site, enclosing_sp) + } +} + +pub mod monotonic { + use std::ops::{Deref, DerefMut}; + + /// A `MonotonicVec` is a `Vec` which can only be grown. + /// Once inserted, an element can never be removed or swapped, + /// guaranteeing that any indices into a `MonotonicVec` are stable + // This is declared in its own module to ensure that the private + // field is inaccessible + pub struct MonotonicVec<T>(Vec<T>); + impl<T> MonotonicVec<T> { + pub fn new(val: Vec<T>) -> MonotonicVec<T> { + MonotonicVec(val) + } + + pub fn push(&mut self, val: T) { + self.0.push(val); + } + } + + impl<T> Default for MonotonicVec<T> { + fn default() -> Self { + MonotonicVec::new(vec![]) + } + } + + impl<T> Deref for MonotonicVec<T> { + type Target = Vec<T>; + fn deref(&self) -> &Self::Target { + &self.0 + } + } + + impl<T> !DerefMut for MonotonicVec<T> {} +} + +#[derive(Clone, Encodable, Decodable, Debug, Copy, HashStable_Generic)] +pub struct Spanned<T> { + pub node: T, + pub span: Span, +} + +pub fn respan<T>(sp: Span, t: T) -> Spanned<T> { + Spanned { node: t, span: sp } +} + +pub fn dummy_spanned<T>(t: T) -> Spanned<T> { + respan(DUMMY_SP, t) +} + +// _____________________________________________________________________________ +// SourceFile, MultiByteChar, FileName, FileLines +// + +/// An abstraction over the fs operations used by the Parser. +pub trait FileLoader { + /// Query the existence of a file. + fn file_exists(&self, path: &Path) -> bool; + + /// Read the contents of a UTF-8 file into memory. + fn read_file(&self, path: &Path) -> io::Result<String>; +} + +/// A FileLoader that uses std::fs to load real files. +pub struct RealFileLoader; + +impl FileLoader for RealFileLoader { + fn file_exists(&self, path: &Path) -> bool { + path.exists() + } + + fn read_file(&self, path: &Path) -> io::Result<String> { + fs::read_to_string(path) + } +} + +/// This is a [SourceFile] identifier that is used to correlate source files between +/// subsequent compilation sessions (which is something we need to do during +/// incremental compilation). +/// +/// The [StableSourceFileId] also contains the CrateNum of the crate the source +/// file was originally parsed for. This way we get two separate entries in +/// the [SourceMap] if the same file is part of both the local and an upstream +/// crate. Trying to only have one entry for both cases is problematic because +/// at the point where we discover that there's a local use of the file in +/// addition to the upstream one, we might already have made decisions based on +/// the assumption that it's an upstream file. Treating the two files as +/// different has no real downsides. +#[derive(Copy, Clone, PartialEq, Eq, Hash, Encodable, Decodable, Debug)] +pub struct StableSourceFileId { + // A hash of the source file's FileName. This is hash so that it's size + // is more predictable than if we included the actual FileName value. + pub file_name_hash: u64, + + // The CrateNum of the crate this source file was originally parsed for. + // We cannot include this information in the hash because at the time + // of hashing we don't have the context to map from the CrateNum's numeric + // value to a StableCrateId. + pub cnum: CrateNum, +} + +// FIXME: we need a more globally consistent approach to the problem solved by +// StableSourceFileId, perhaps built atop source_file.name_hash. +impl StableSourceFileId { + pub fn new(source_file: &SourceFile) -> StableSourceFileId { + StableSourceFileId::new_from_name(&source_file.name, source_file.cnum) + } + + fn new_from_name(name: &FileName, cnum: CrateNum) -> StableSourceFileId { + let mut hasher = StableHasher::new(); + name.hash(&mut hasher); + StableSourceFileId { file_name_hash: hasher.finish(), cnum } + } +} + +// _____________________________________________________________________________ +// SourceMap +// + +#[derive(Default)] +pub(super) struct SourceMapFiles { + source_files: monotonic::MonotonicVec<Lrc<SourceFile>>, + stable_id_to_source_file: FxHashMap<StableSourceFileId, Lrc<SourceFile>>, +} + +pub struct SourceMap { + /// The address space below this value is currently used by the files in the source map. + used_address_space: AtomicU32, + + files: RwLock<SourceMapFiles>, + file_loader: Box<dyn FileLoader + Sync + Send>, + // This is used to apply the file path remapping as specified via + // `--remap-path-prefix` to all `SourceFile`s allocated within this `SourceMap`. + path_mapping: FilePathMapping, + + /// The algorithm used for hashing the contents of each source file. + hash_kind: SourceFileHashAlgorithm, +} + +impl SourceMap { + pub fn new(path_mapping: FilePathMapping) -> SourceMap { + Self::with_file_loader_and_hash_kind( + Box::new(RealFileLoader), + path_mapping, + SourceFileHashAlgorithm::Md5, + ) + } + + pub fn with_file_loader_and_hash_kind( + file_loader: Box<dyn FileLoader + Sync + Send>, + path_mapping: FilePathMapping, + hash_kind: SourceFileHashAlgorithm, + ) -> SourceMap { + SourceMap { + used_address_space: AtomicU32::new(0), + files: Default::default(), + file_loader, + path_mapping, + hash_kind, + } + } + + pub fn path_mapping(&self) -> &FilePathMapping { + &self.path_mapping + } + + pub fn file_exists(&self, path: &Path) -> bool { + self.file_loader.file_exists(path) + } + + pub fn load_file(&self, path: &Path) -> io::Result<Lrc<SourceFile>> { + let src = self.file_loader.read_file(path)?; + let filename = path.to_owned().into(); + Ok(self.new_source_file(filename, src)) + } + + /// Loads source file as a binary blob. + /// + /// Unlike `load_file`, guarantees that no normalization like BOM-removal + /// takes place. + pub fn load_binary_file(&self, path: &Path) -> io::Result<Vec<u8>> { + // Ideally, this should use `self.file_loader`, but it can't + // deal with binary files yet. + let bytes = fs::read(path)?; + + // We need to add file to the `SourceMap`, so that it is present + // in dep-info. There's also an edge case that file might be both + // loaded as a binary via `include_bytes!` and as proper `SourceFile` + // via `mod`, so we try to use real file contents and not just an + // empty string. + let text = std::str::from_utf8(&bytes).unwrap_or("").to_string(); + self.new_source_file(path.to_owned().into(), text); + Ok(bytes) + } + + // By returning a `MonotonicVec`, we ensure that consumers cannot invalidate + // any existing indices pointing into `files`. + pub fn files(&self) -> MappedReadGuard<'_, monotonic::MonotonicVec<Lrc<SourceFile>>> { + ReadGuard::map(self.files.borrow(), |files| &files.source_files) + } + + pub fn source_file_by_stable_id( + &self, + stable_id: StableSourceFileId, + ) -> Option<Lrc<SourceFile>> { + self.files.borrow().stable_id_to_source_file.get(&stable_id).cloned() + } + + fn allocate_address_space(&self, size: usize) -> Result<usize, OffsetOverflowError> { + let size = u32::try_from(size).map_err(|_| OffsetOverflowError)?; + + loop { + let current = self.used_address_space.load(Ordering::Relaxed); + let next = current + .checked_add(size) + // Add one so there is some space between files. This lets us distinguish + // positions in the `SourceMap`, even in the presence of zero-length files. + .and_then(|next| next.checked_add(1)) + .ok_or(OffsetOverflowError)?; + + if self + .used_address_space + .compare_exchange(current, next, Ordering::Relaxed, Ordering::Relaxed) + .is_ok() + { + return Ok(usize::try_from(current).unwrap()); + } + } + } + + /// Creates a new `SourceFile`. + /// If a file already exists in the `SourceMap` with the same ID, that file is returned + /// unmodified. + pub fn new_source_file(&self, filename: FileName, src: String) -> Lrc<SourceFile> { + self.try_new_source_file(filename, src).unwrap_or_else(|OffsetOverflowError| { + eprintln!("fatal error: rustc does not support files larger than 4GB"); + crate::fatal_error::FatalError.raise() + }) + } + + fn try_new_source_file( + &self, + filename: FileName, + src: String, + ) -> Result<Lrc<SourceFile>, OffsetOverflowError> { + // Note that filename may not be a valid path, eg it may be `<anon>` etc, + // but this is okay because the directory determined by `path.pop()` will + // be empty, so the working directory will be used. + let (filename, _) = self.path_mapping.map_filename_prefix(&filename); + + let file_id = StableSourceFileId::new_from_name(&filename, LOCAL_CRATE); + + let lrc_sf = match self.source_file_by_stable_id(file_id) { + Some(lrc_sf) => lrc_sf, + None => { + let start_pos = self.allocate_address_space(src.len())?; + + let source_file = Lrc::new(SourceFile::new( + filename, + src, + Pos::from_usize(start_pos), + self.hash_kind, + )); + + // Let's make sure the file_id we generated above actually matches + // the ID we generate for the SourceFile we just created. + debug_assert_eq!(StableSourceFileId::new(&source_file), file_id); + + let mut files = self.files.borrow_mut(); + + files.source_files.push(source_file.clone()); + files.stable_id_to_source_file.insert(file_id, source_file.clone()); + + source_file + } + }; + Ok(lrc_sf) + } + + /// Allocates a new `SourceFile` representing a source file from an external + /// crate. The source code of such an "imported `SourceFile`" is not available, + /// but we still know enough to generate accurate debuginfo location + /// information for things inlined from other crates. + pub fn new_imported_source_file( + &self, + filename: FileName, + src_hash: SourceFileHash, + name_hash: u128, + source_len: usize, + cnum: CrateNum, + file_local_lines: Lock<SourceFileLines>, + mut file_local_multibyte_chars: Vec<MultiByteChar>, + mut file_local_non_narrow_chars: Vec<NonNarrowChar>, + mut file_local_normalized_pos: Vec<NormalizedPos>, + original_start_pos: BytePos, + original_end_pos: BytePos, + ) -> Lrc<SourceFile> { + let start_pos = self + .allocate_address_space(source_len) + .expect("not enough address space for imported source file"); + + let end_pos = Pos::from_usize(start_pos + source_len); + let start_pos = Pos::from_usize(start_pos); + + // Translate these positions into the new global frame of reference, + // now that the offset of the SourceFile is known. + // + // These are all unsigned values. `original_start_pos` may be larger or + // smaller than `start_pos`, but `pos` is always larger than both. + // Therefore, `(pos - original_start_pos) + start_pos` won't overflow + // but `start_pos - original_start_pos` might. So we use the former + // form rather than pre-computing the offset into a local variable. The + // compiler backend can optimize away the repeated computations in a + // way that won't trigger overflow checks. + match &mut *file_local_lines.borrow_mut() { + SourceFileLines::Lines(lines) => { + for pos in lines { + *pos = (*pos - original_start_pos) + start_pos; + } + } + SourceFileLines::Diffs(SourceFileDiffs { line_start, .. }) => { + *line_start = (*line_start - original_start_pos) + start_pos; + } + } + for mbc in &mut file_local_multibyte_chars { + mbc.pos = (mbc.pos - original_start_pos) + start_pos; + } + for swc in &mut file_local_non_narrow_chars { + *swc = (*swc - original_start_pos) + start_pos; + } + for nc in &mut file_local_normalized_pos { + nc.pos = (nc.pos - original_start_pos) + start_pos; + } + + let source_file = Lrc::new(SourceFile { + name: filename, + src: None, + src_hash, + external_src: Lock::new(ExternalSource::Foreign { + kind: ExternalSourceKind::AbsentOk, + original_start_pos, + original_end_pos, + }), + start_pos, + end_pos, + lines: file_local_lines, + multibyte_chars: file_local_multibyte_chars, + non_narrow_chars: file_local_non_narrow_chars, + normalized_pos: file_local_normalized_pos, + name_hash, + cnum, + }); + + let mut files = self.files.borrow_mut(); + + files.source_files.push(source_file.clone()); + files + .stable_id_to_source_file + .insert(StableSourceFileId::new(&source_file), source_file.clone()); + + source_file + } + + // If there is a doctest offset, applies it to the line. + pub fn doctest_offset_line(&self, file: &FileName, orig: usize) -> usize { + match file { + FileName::DocTest(_, offset) => { + if *offset < 0 { + orig - (-(*offset)) as usize + } else { + orig + *offset as usize + } + } + _ => orig, + } + } + + /// Return the SourceFile that contains the given `BytePos` + pub fn lookup_source_file(&self, pos: BytePos) -> Lrc<SourceFile> { + let idx = self.lookup_source_file_idx(pos); + (*self.files.borrow().source_files)[idx].clone() + } + + /// Looks up source information about a `BytePos`. + pub fn lookup_char_pos(&self, pos: BytePos) -> Loc { + let sf = self.lookup_source_file(pos); + let (line, col, col_display) = sf.lookup_file_pos_with_col_display(pos); + Loc { file: sf, line, col, col_display } + } + + // If the corresponding `SourceFile` is empty, does not return a line number. + pub fn lookup_line(&self, pos: BytePos) -> Result<SourceFileAndLine, Lrc<SourceFile>> { + let f = self.lookup_source_file(pos); + + match f.lookup_line(pos) { + Some(line) => Ok(SourceFileAndLine { sf: f, line }), + None => Err(f), + } + } + + fn span_to_string(&self, sp: Span, filename_display_pref: FileNameDisplayPreference) -> String { + if self.files.borrow().source_files.is_empty() || sp.is_dummy() { + return "no-location".to_string(); + } + + let lo = self.lookup_char_pos(sp.lo()); + let hi = self.lookup_char_pos(sp.hi()); + format!( + "{}:{}:{}: {}:{}", + lo.file.name.display(filename_display_pref), + lo.line, + lo.col.to_usize() + 1, + hi.line, + hi.col.to_usize() + 1, + ) + } + + /// Format the span location suitable for embedding in build artifacts + pub fn span_to_embeddable_string(&self, sp: Span) -> String { + self.span_to_string(sp, FileNameDisplayPreference::Remapped) + } + + /// Format the span location suitable for pretty printing anotations with relative line numbers + pub fn span_to_relative_line_string(&self, sp: Span, relative_to: Span) -> String { + if self.files.borrow().source_files.is_empty() || sp.is_dummy() || relative_to.is_dummy() { + return "no-location".to_string(); + } + + let lo = self.lookup_char_pos(sp.lo()); + let hi = self.lookup_char_pos(sp.hi()); + let offset = self.lookup_char_pos(relative_to.lo()); + + if lo.file.name != offset.file.name { + return self.span_to_embeddable_string(sp); + } + + let lo_line = lo.line.saturating_sub(offset.line); + let hi_line = hi.line.saturating_sub(offset.line); + + format!( + "{}:+{}:{}: +{}:{}", + lo.file.name.display(FileNameDisplayPreference::Remapped), + lo_line, + lo.col.to_usize() + 1, + hi_line, + hi.col.to_usize() + 1, + ) + } + + /// Format the span location to be printed in diagnostics. Must not be emitted + /// to build artifacts as this may leak local file paths. Use span_to_embeddable_string + /// for string suitable for embedding. + pub fn span_to_diagnostic_string(&self, sp: Span) -> String { + self.span_to_string(sp, self.path_mapping.filename_display_for_diagnostics) + } + + pub fn span_to_filename(&self, sp: Span) -> FileName { + self.lookup_char_pos(sp.lo()).file.name.clone() + } + + pub fn filename_for_diagnostics<'a>(&self, filename: &'a FileName) -> FileNameDisplay<'a> { + filename.display(self.path_mapping.filename_display_for_diagnostics) + } + + pub fn is_multiline(&self, sp: Span) -> bool { + let lo = self.lookup_source_file_idx(sp.lo()); + let hi = self.lookup_source_file_idx(sp.hi()); + if lo != hi { + return true; + } + let f = (*self.files.borrow().source_files)[lo].clone(); + f.lookup_line(sp.lo()) != f.lookup_line(sp.hi()) + } + + #[instrument(skip(self), level = "trace")] + pub fn is_valid_span(&self, sp: Span) -> Result<(Loc, Loc), SpanLinesError> { + let lo = self.lookup_char_pos(sp.lo()); + trace!(?lo); + let hi = self.lookup_char_pos(sp.hi()); + trace!(?hi); + if lo.file.start_pos != hi.file.start_pos { + return Err(SpanLinesError::DistinctSources(DistinctSources { + begin: (lo.file.name.clone(), lo.file.start_pos), + end: (hi.file.name.clone(), hi.file.start_pos), + })); + } + Ok((lo, hi)) + } + + pub fn is_line_before_span_empty(&self, sp: Span) -> bool { + match self.span_to_prev_source(sp) { + Ok(s) => s.rsplit_once('\n').unwrap_or(("", &s)).1.trim_start().is_empty(), + Err(_) => false, + } + } + + pub fn span_to_lines(&self, sp: Span) -> FileLinesResult { + debug!("span_to_lines(sp={:?})", sp); + let (lo, hi) = self.is_valid_span(sp)?; + assert!(hi.line >= lo.line); + + if sp.is_dummy() { + return Ok(FileLines { file: lo.file, lines: Vec::new() }); + } + + let mut lines = Vec::with_capacity(hi.line - lo.line + 1); + + // The span starts partway through the first line, + // but after that it starts from offset 0. + let mut start_col = lo.col; + + // For every line but the last, it extends from `start_col` + // and to the end of the line. Be careful because the line + // numbers in Loc are 1-based, so we subtract 1 to get 0-based + // lines. + // + // FIXME: now that we handle DUMMY_SP up above, we should consider + // asserting that the line numbers here are all indeed 1-based. + let hi_line = hi.line.saturating_sub(1); + for line_index in lo.line.saturating_sub(1)..hi_line { + let line_len = lo.file.get_line(line_index).map_or(0, |s| s.chars().count()); + lines.push(LineInfo { line_index, start_col, end_col: CharPos::from_usize(line_len) }); + start_col = CharPos::from_usize(0); + } + + // For the last line, it extends from `start_col` to `hi.col`: + lines.push(LineInfo { line_index: hi_line, start_col, end_col: hi.col }); + + Ok(FileLines { file: lo.file, lines }) + } + + /// Extracts the source surrounding the given `Span` using the `extract_source` function. The + /// extract function takes three arguments: a string slice containing the source, an index in + /// the slice for the beginning of the span and an index in the slice for the end of the span. + fn span_to_source<F, T>(&self, sp: Span, extract_source: F) -> Result<T, SpanSnippetError> + where + F: Fn(&str, usize, usize) -> Result<T, SpanSnippetError>, + { + let local_begin = self.lookup_byte_offset(sp.lo()); + let local_end = self.lookup_byte_offset(sp.hi()); + + if local_begin.sf.start_pos != local_end.sf.start_pos { + Err(SpanSnippetError::DistinctSources(DistinctSources { + begin: (local_begin.sf.name.clone(), local_begin.sf.start_pos), + end: (local_end.sf.name.clone(), local_end.sf.start_pos), + })) + } else { + self.ensure_source_file_source_present(local_begin.sf.clone()); + + let start_index = local_begin.pos.to_usize(); + let end_index = local_end.pos.to_usize(); + let source_len = (local_begin.sf.end_pos - local_begin.sf.start_pos).to_usize(); + + if start_index > end_index || end_index > source_len { + return Err(SpanSnippetError::MalformedForSourcemap(MalformedSourceMapPositions { + name: local_begin.sf.name.clone(), + source_len, + begin_pos: local_begin.pos, + end_pos: local_end.pos, + })); + } + + if let Some(ref src) = local_begin.sf.src { + extract_source(src, start_index, end_index) + } else if let Some(src) = local_begin.sf.external_src.borrow().get_source() { + extract_source(src, start_index, end_index) + } else { + Err(SpanSnippetError::SourceNotAvailable { filename: local_begin.sf.name.clone() }) + } + } + } + + pub fn is_span_accessible(&self, sp: Span) -> bool { + self.span_to_source(sp, |src, start_index, end_index| { + Ok(src.get(start_index..end_index).is_some()) + }) + .map_or(false, |is_accessible| is_accessible) + } + + /// Returns the source snippet as `String` corresponding to the given `Span`. + pub fn span_to_snippet(&self, sp: Span) -> Result<String, SpanSnippetError> { + self.span_to_source(sp, |src, start_index, end_index| { + src.get(start_index..end_index) + .map(|s| s.to_string()) + .ok_or(SpanSnippetError::IllFormedSpan(sp)) + }) + } + + pub fn span_to_margin(&self, sp: Span) -> Option<usize> { + Some(self.indentation_before(sp)?.len()) + } + + pub fn indentation_before(&self, sp: Span) -> Option<String> { + self.span_to_source(sp, |src, start_index, _| { + let before = &src[..start_index]; + let last_line = before.rsplit_once('\n').map_or(before, |(_, last)| last); + Ok(last_line + .split_once(|c: char| !c.is_whitespace()) + .map_or(last_line, |(indent, _)| indent) + .to_string()) + }) + .ok() + } + + /// Returns the source snippet as `String` before the given `Span`. + pub fn span_to_prev_source(&self, sp: Span) -> Result<String, SpanSnippetError> { + self.span_to_source(sp, |src, start_index, _| { + src.get(..start_index).map(|s| s.to_string()).ok_or(SpanSnippetError::IllFormedSpan(sp)) + }) + } + + /// Extends the given `Span` to just after the previous occurrence of `c`. Return the same span + /// if no character could be found or if an error occurred while retrieving the code snippet. + pub fn span_extend_to_prev_char(&self, sp: Span, c: char, accept_newlines: bool) -> Span { + if let Ok(prev_source) = self.span_to_prev_source(sp) { + let prev_source = prev_source.rsplit(c).next().unwrap_or(""); + if !prev_source.is_empty() && (accept_newlines || !prev_source.contains('\n')) { + return sp.with_lo(BytePos(sp.lo().0 - prev_source.len() as u32)); + } + } + + sp + } + + /// Extends the given `Span` to just after the previous occurrence of `pat` when surrounded by + /// whitespace. Returns None if the pattern could not be found or if an error occurred while + /// retrieving the code snippet. + pub fn span_extend_to_prev_str( + &self, + sp: Span, + pat: &str, + accept_newlines: bool, + include_whitespace: bool, + ) -> Option<Span> { + // assure that the pattern is delimited, to avoid the following + // fn my_fn() + // ^^^^ returned span without the check + // ---------- correct span + let prev_source = self.span_to_prev_source(sp).ok()?; + for ws in &[" ", "\t", "\n"] { + let pat = pat.to_owned() + ws; + if let Some(pat_pos) = prev_source.rfind(&pat) { + let just_after_pat_pos = pat_pos + pat.len() - 1; + let just_after_pat_plus_ws = if include_whitespace { + just_after_pat_pos + + prev_source[just_after_pat_pos..] + .find(|c: char| !c.is_whitespace()) + .unwrap_or(0) + } else { + just_after_pat_pos + }; + let len = prev_source.len() - just_after_pat_plus_ws; + let prev_source = &prev_source[just_after_pat_plus_ws..]; + if accept_newlines || !prev_source.trim_start().contains('\n') { + return Some(sp.with_lo(BytePos(sp.lo().0 - len as u32))); + } + } + } + + None + } + + /// Returns the source snippet as `String` after the given `Span`. + pub fn span_to_next_source(&self, sp: Span) -> Result<String, SpanSnippetError> { + self.span_to_source(sp, |src, _, end_index| { + src.get(end_index..).map(|s| s.to_string()).ok_or(SpanSnippetError::IllFormedSpan(sp)) + }) + } + + /// Extends the given `Span` while the next character matches the predicate + pub fn span_extend_while( + &self, + span: Span, + f: impl Fn(char) -> bool, + ) -> Result<Span, SpanSnippetError> { + self.span_to_source(span, |s, _start, end| { + let n = s[end..].char_indices().find(|&(_, c)| !f(c)).map_or(s.len() - end, |(i, _)| i); + Ok(span.with_hi(span.hi() + BytePos(n as u32))) + }) + } + + /// Extends the given `Span` to just after the next occurrence of `c`. + pub fn span_extend_to_next_char(&self, sp: Span, c: char, accept_newlines: bool) -> Span { + if let Ok(next_source) = self.span_to_next_source(sp) { + let next_source = next_source.split(c).next().unwrap_or(""); + if !next_source.is_empty() && (accept_newlines || !next_source.contains('\n')) { + return sp.with_hi(BytePos(sp.hi().0 + next_source.len() as u32)); + } + } + + sp + } + + /// Extends the given `Span` to contain the entire line it is on. + pub fn span_extend_to_line(&self, sp: Span) -> Span { + self.span_extend_to_prev_char(self.span_extend_to_next_char(sp, '\n', true), '\n', true) + } + + /// Given a `Span`, tries to get a shorter span ending before the first occurrence of `char` + /// `c`. + pub fn span_until_char(&self, sp: Span, c: char) -> Span { + match self.span_to_snippet(sp) { + Ok(snippet) => { + let snippet = snippet.split(c).next().unwrap_or("").trim_end(); + if !snippet.is_empty() && !snippet.contains('\n') { + sp.with_hi(BytePos(sp.lo().0 + snippet.len() as u32)) + } else { + sp + } + } + _ => sp, + } + } + + /// Given a `Span`, tries to get a shorter span ending just after the first occurrence of `char` + /// `c`. + pub fn span_through_char(&self, sp: Span, c: char) -> Span { + if let Ok(snippet) = self.span_to_snippet(sp) { + if let Some(offset) = snippet.find(c) { + return sp.with_hi(BytePos(sp.lo().0 + (offset + c.len_utf8()) as u32)); + } + } + sp + } + + /// Given a `Span`, gets a new `Span` covering the first token and all its trailing whitespace + /// or the original `Span`. + /// + /// If `sp` points to `"let mut x"`, then a span pointing at `"let "` will be returned. + pub fn span_until_non_whitespace(&self, sp: Span) -> Span { + let mut whitespace_found = false; + + self.span_take_while(sp, |c| { + if !whitespace_found && c.is_whitespace() { + whitespace_found = true; + } + + !whitespace_found || c.is_whitespace() + }) + } + + /// Given a `Span`, gets a new `Span` covering the first token without its trailing whitespace + /// or the original `Span` in case of error. + /// + /// If `sp` points to `"let mut x"`, then a span pointing at `"let"` will be returned. + pub fn span_until_whitespace(&self, sp: Span) -> Span { + self.span_take_while(sp, |c| !c.is_whitespace()) + } + + /// Given a `Span`, gets a shorter one until `predicate` yields `false`. + pub fn span_take_while<P>(&self, sp: Span, predicate: P) -> Span + where + P: for<'r> FnMut(&'r char) -> bool, + { + if let Ok(snippet) = self.span_to_snippet(sp) { + let offset = snippet.chars().take_while(predicate).map(|c| c.len_utf8()).sum::<usize>(); + + sp.with_hi(BytePos(sp.lo().0 + (offset as u32))) + } else { + sp + } + } + + /// Given a `Span`, return a span ending in the closest `{`. This is useful when you have a + /// `Span` enclosing a whole item but we need to point at only the head (usually the first + /// line) of that item. + /// + /// *Only suitable for diagnostics.* + pub fn guess_head_span(&self, sp: Span) -> Span { + // FIXME: extend the AST items to have a head span, or replace callers with pointing at + // the item's ident when appropriate. + self.span_until_char(sp, '{') + } + + /// Returns a new span representing just the first character of the given span. + pub fn start_point(&self, sp: Span) -> Span { + let width = { + let sp = sp.data(); + let local_begin = self.lookup_byte_offset(sp.lo); + let start_index = local_begin.pos.to_usize(); + let src = local_begin.sf.external_src.borrow(); + + let snippet = if let Some(ref src) = local_begin.sf.src { + Some(&src[start_index..]) + } else if let Some(src) = src.get_source() { + Some(&src[start_index..]) + } else { + None + }; + + match snippet { + None => 1, + Some(snippet) => match snippet.chars().next() { + None => 1, + Some(c) => c.len_utf8(), + }, + } + }; + + sp.with_hi(BytePos(sp.lo().0 + width as u32)) + } + + /// Returns a new span representing just the last character of this span. + pub fn end_point(&self, sp: Span) -> Span { + let pos = sp.hi().0; + + let width = self.find_width_of_character_at_span(sp, false); + let corrected_end_position = pos.checked_sub(width).unwrap_or(pos); + + let end_point = BytePos(cmp::max(corrected_end_position, sp.lo().0)); + sp.with_lo(end_point) + } + + /// Returns a new span representing the next character after the end-point of this span. + pub fn next_point(&self, sp: Span) -> Span { + if sp.is_dummy() { + return sp; + } + let start_of_next_point = sp.hi().0; + + let width = self.find_width_of_character_at_span(sp.shrink_to_hi(), true); + // If the width is 1, then the next span should point to the same `lo` and `hi`. However, + // in the case of a multibyte character, where the width != 1, the next span should + // span multiple bytes to include the whole character. + let end_of_next_point = + start_of_next_point.checked_add(width - 1).unwrap_or(start_of_next_point); + + let end_of_next_point = BytePos(cmp::max(sp.lo().0 + 1, end_of_next_point)); + Span::new(BytePos(start_of_next_point), end_of_next_point, sp.ctxt(), None) + } + + /// Finds the width of the character, either before or after the end of provided span, + /// depending on the `forwards` parameter. + fn find_width_of_character_at_span(&self, sp: Span, forwards: bool) -> u32 { + let sp = sp.data(); + if sp.lo == sp.hi { + debug!("find_width_of_character_at_span: early return empty span"); + return 1; + } + + let local_begin = self.lookup_byte_offset(sp.lo); + let local_end = self.lookup_byte_offset(sp.hi); + debug!( + "find_width_of_character_at_span: local_begin=`{:?}`, local_end=`{:?}`", + local_begin, local_end + ); + + if local_begin.sf.start_pos != local_end.sf.start_pos { + debug!("find_width_of_character_at_span: begin and end are in different files"); + return 1; + } + + let start_index = local_begin.pos.to_usize(); + let end_index = local_end.pos.to_usize(); + debug!( + "find_width_of_character_at_span: start_index=`{:?}`, end_index=`{:?}`", + start_index, end_index + ); + + // Disregard indexes that are at the start or end of their spans, they can't fit bigger + // characters. + if (!forwards && end_index == usize::MIN) || (forwards && start_index == usize::MAX) { + debug!("find_width_of_character_at_span: start or end of span, cannot be multibyte"); + return 1; + } + + let source_len = (local_begin.sf.end_pos - local_begin.sf.start_pos).to_usize(); + debug!("find_width_of_character_at_span: source_len=`{:?}`", source_len); + // Ensure indexes are also not malformed. + if start_index > end_index || end_index > source_len { + debug!("find_width_of_character_at_span: source indexes are malformed"); + return 1; + } + + let src = local_begin.sf.external_src.borrow(); + + // We need to extend the snippet to the end of the src rather than to end_index so when + // searching forwards for boundaries we've got somewhere to search. + let snippet = if let Some(ref src) = local_begin.sf.src { + &src[start_index..] + } else if let Some(src) = src.get_source() { + &src[start_index..] + } else { + return 1; + }; + debug!("find_width_of_character_at_span: snippet=`{:?}`", snippet); + + let mut target = if forwards { end_index + 1 } else { end_index - 1 }; + debug!("find_width_of_character_at_span: initial target=`{:?}`", target); + + while !snippet.is_char_boundary(target - start_index) && target < source_len { + target = if forwards { + target + 1 + } else { + match target.checked_sub(1) { + Some(target) => target, + None => { + break; + } + } + }; + debug!("find_width_of_character_at_span: target=`{:?}`", target); + } + debug!("find_width_of_character_at_span: final target=`{:?}`", target); + + if forwards { (target - end_index) as u32 } else { (end_index - target) as u32 } + } + + pub fn get_source_file(&self, filename: &FileName) -> Option<Lrc<SourceFile>> { + // Remap filename before lookup + let filename = self.path_mapping().map_filename_prefix(filename).0; + for sf in self.files.borrow().source_files.iter() { + if filename == sf.name { + return Some(sf.clone()); + } + } + None + } + + /// For a global `BytePos`, computes the local offset within the containing `SourceFile`. + pub fn lookup_byte_offset(&self, bpos: BytePos) -> SourceFileAndBytePos { + let idx = self.lookup_source_file_idx(bpos); + let sf = (*self.files.borrow().source_files)[idx].clone(); + let offset = bpos - sf.start_pos; + SourceFileAndBytePos { sf, pos: offset } + } + + // Returns the index of the `SourceFile` (in `self.files`) that contains `pos`. + // This index is guaranteed to be valid for the lifetime of this `SourceMap`, + // since `source_files` is a `MonotonicVec` + pub fn lookup_source_file_idx(&self, pos: BytePos) -> usize { + self.files + .borrow() + .source_files + .binary_search_by_key(&pos, |key| key.start_pos) + .unwrap_or_else(|p| p - 1) + } + + pub fn count_lines(&self) -> usize { + self.files().iter().fold(0, |a, f| a + f.count_lines()) + } + + pub fn generate_fn_name_span(&self, span: Span) -> Option<Span> { + let prev_span = self.span_extend_to_prev_str(span, "fn", true, true)?; + if let Ok(snippet) = self.span_to_snippet(prev_span) { + debug!( + "generate_fn_name_span: span={:?}, prev_span={:?}, snippet={:?}", + span, prev_span, snippet + ); + + if snippet.is_empty() { + return None; + }; + + let len = snippet + .find(|c: char| !c.is_alphanumeric() && c != '_') + .expect("no label after fn"); + Some(prev_span.with_hi(BytePos(prev_span.lo().0 + len as u32))) + } else { + None + } + } + + /// Takes the span of a type parameter in a function signature and try to generate a span for + /// the function name (with generics) and a new snippet for this span with the pointed type + /// parameter as a new local type parameter. + /// + /// For instance: + /// ```rust,ignore (pseudo-Rust) + /// // Given span + /// fn my_function(param: T) + /// // ^ Original span + /// + /// // Result + /// fn my_function(param: T) + /// // ^^^^^^^^^^^ Generated span with snippet `my_function<T>` + /// ``` + /// + /// Attention: The method used is very fragile since it essentially duplicates the work of the + /// parser. If you need to use this function or something similar, please consider updating the + /// `SourceMap` functions and this function to something more robust. + pub fn generate_local_type_param_snippet(&self, span: Span) -> Option<(Span, String)> { + // Try to extend the span to the previous "fn" keyword to retrieve the function + // signature. + if let Some(sugg_span) = self.span_extend_to_prev_str(span, "fn", false, true) { + if let Ok(snippet) = self.span_to_snippet(sugg_span) { + // Consume the function name. + let mut offset = snippet + .find(|c: char| !c.is_alphanumeric() && c != '_') + .expect("no label after fn"); + + // Consume the generics part of the function signature. + let mut bracket_counter = 0; + let mut last_char = None; + for c in snippet[offset..].chars() { + match c { + '<' => bracket_counter += 1, + '>' => bracket_counter -= 1, + '(' => { + if bracket_counter == 0 { + break; + } + } + _ => {} + } + offset += c.len_utf8(); + last_char = Some(c); + } + + // Adjust the suggestion span to encompass the function name with its generics. + let sugg_span = sugg_span.with_hi(BytePos(sugg_span.lo().0 + offset as u32)); + + // Prepare the new suggested snippet to append the type parameter that triggered + // the error in the generics of the function signature. + let mut new_snippet = if last_char == Some('>') { + format!("{}, ", &snippet[..(offset - '>'.len_utf8())]) + } else { + format!("{}<", &snippet[..offset]) + }; + new_snippet + .push_str(&self.span_to_snippet(span).unwrap_or_else(|_| "T".to_string())); + new_snippet.push('>'); + + return Some((sugg_span, new_snippet)); + } + } + + None + } + pub fn ensure_source_file_source_present(&self, source_file: Lrc<SourceFile>) -> bool { + source_file.add_external_src(|| { + match source_file.name { + FileName::Real(ref name) if let Some(local_path) = name.local_path() => { + self.file_loader.read_file(local_path).ok() + } + _ => None, + } + }) + } + + pub fn is_imported(&self, sp: Span) -> bool { + let source_file_index = self.lookup_source_file_idx(sp.lo()); + let source_file = &self.files()[source_file_index]; + source_file.is_imported() + } + + /// Gets the span of a statement. If the statement is a macro expansion, the + /// span in the context of the block span is found. The trailing semicolon is included + /// on a best-effort basis. + pub fn stmt_span(&self, stmt_span: Span, block_span: Span) -> Span { + if !stmt_span.from_expansion() { + return stmt_span; + } + let mac_call = original_sp(stmt_span, block_span); + self.mac_call_stmt_semi_span(mac_call).map_or(mac_call, |s| mac_call.with_hi(s.hi())) + } + + /// Tries to find the span of the semicolon of a macro call statement. + /// The input must be the *call site* span of a statement from macro expansion. + /// ```ignore (illustrative) + /// // v output + /// mac!(); + /// // ^^^^^^ input + /// ``` + pub fn mac_call_stmt_semi_span(&self, mac_call: Span) -> Option<Span> { + let span = self.span_extend_while(mac_call, char::is_whitespace).ok()?; + let span = span.shrink_to_hi().with_hi(BytePos(span.hi().0.checked_add(1)?)); + if self.span_to_snippet(span).as_deref() != Ok(";") { + return None; + } + Some(span) + } +} + +#[derive(Clone)] +pub struct FilePathMapping { + mapping: Vec<(PathBuf, PathBuf)>, + filename_display_for_diagnostics: FileNameDisplayPreference, +} + +impl FilePathMapping { + pub fn empty() -> FilePathMapping { + FilePathMapping::new(Vec::new()) + } + + pub fn new(mapping: Vec<(PathBuf, PathBuf)>) -> FilePathMapping { + let filename_display_for_diagnostics = if mapping.is_empty() { + FileNameDisplayPreference::Local + } else { + FileNameDisplayPreference::Remapped + }; + + FilePathMapping { mapping, filename_display_for_diagnostics } + } + + /// Applies any path prefix substitution as defined by the mapping. + /// The return value is the remapped path and a boolean indicating whether + /// the path was affected by the mapping. + pub fn map_prefix(&self, path: PathBuf) -> (PathBuf, bool) { + if path.as_os_str().is_empty() { + // Exit early if the path is empty and therefore there's nothing to remap. + // This is mostly to reduce spam for `RUSTC_LOG=[remap_path_prefix]`. + return (path, false); + } + + return remap_path_prefix(&self.mapping, path); + + #[instrument(level = "debug", skip(mapping))] + fn remap_path_prefix(mapping: &[(PathBuf, PathBuf)], path: PathBuf) -> (PathBuf, bool) { + // NOTE: We are iterating over the mapping entries from last to first + // because entries specified later on the command line should + // take precedence. + for &(ref from, ref to) in mapping.iter().rev() { + debug!("Trying to apply {:?} => {:?}", from, to); + + if let Ok(rest) = path.strip_prefix(from) { + let remapped = if rest.as_os_str().is_empty() { + // This is subtle, joining an empty path onto e.g. `foo/bar` will + // result in `foo/bar/`, that is, there'll be an additional directory + // separator at the end. This can lead to duplicated directory separators + // in remapped paths down the line. + // So, if we have an exact match, we just return that without a call + // to `Path::join()`. + to.clone() + } else { + to.join(rest) + }; + debug!("Match - remapped {:?} => {:?}", path, remapped); + + return (remapped, true); + } else { + debug!("No match - prefix {:?} does not match {:?}", from, path); + } + } + + debug!("Path {:?} was not remapped", path); + (path, false) + } + } + + fn map_filename_prefix(&self, file: &FileName) -> (FileName, bool) { + match file { + FileName::Real(realfile) if let RealFileName::LocalPath(local_path) = realfile => { + let (mapped_path, mapped) = self.map_prefix(local_path.to_path_buf()); + let realfile = if mapped { + RealFileName::Remapped { + local_path: Some(local_path.clone()), + virtual_name: mapped_path, + } + } else { + realfile.clone() + }; + (FileName::Real(realfile), mapped) + } + FileName::Real(_) => unreachable!("attempted to remap an already remapped filename"), + other => (other.clone(), false), + } + } + + /// Expand a relative path to an absolute path with remapping taken into account. + /// Use this when absolute paths are required (e.g. debuginfo or crate metadata). + /// + /// The resulting `RealFileName` will have its `local_path` portion erased if + /// possible (i.e. if there's also a remapped path). + pub fn to_embeddable_absolute_path( + &self, + file_path: RealFileName, + working_directory: &RealFileName, + ) -> RealFileName { + match file_path { + // Anything that's already remapped we don't modify, except for erasing + // the `local_path` portion. + RealFileName::Remapped { local_path: _, virtual_name } => { + RealFileName::Remapped { + // We do not want any local path to be exported into metadata + local_path: None, + // We use the remapped name verbatim, even if it looks like a relative + // path. The assumption is that the user doesn't want us to further + // process paths that have gone through remapping. + virtual_name, + } + } + + RealFileName::LocalPath(unmapped_file_path) => { + // If no remapping has been applied yet, try to do so + let (new_path, was_remapped) = self.map_prefix(unmapped_file_path); + if was_remapped { + // It was remapped, so don't modify further + return RealFileName::Remapped { local_path: None, virtual_name: new_path }; + } + + if new_path.is_absolute() { + // No remapping has applied to this path and it is absolute, + // so the working directory cannot influence it either, so + // we are done. + return RealFileName::LocalPath(new_path); + } + + debug_assert!(new_path.is_relative()); + let unmapped_file_path_rel = new_path; + + match working_directory { + RealFileName::LocalPath(unmapped_working_dir_abs) => { + let file_path_abs = unmapped_working_dir_abs.join(unmapped_file_path_rel); + + // Although neither `working_directory` nor the file name were subject + // to path remapping, the concatenation between the two may be. Hence + // we need to do a remapping here. + let (file_path_abs, was_remapped) = self.map_prefix(file_path_abs); + if was_remapped { + RealFileName::Remapped { + // Erase the actual path + local_path: None, + virtual_name: file_path_abs, + } + } else { + // No kind of remapping applied to this path, so + // we leave it as it is. + RealFileName::LocalPath(file_path_abs) + } + } + RealFileName::Remapped { + local_path: _, + virtual_name: remapped_working_dir_abs, + } => { + // If working_directory has been remapped, then we emit + // Remapped variant as the expanded path won't be valid + RealFileName::Remapped { + local_path: None, + virtual_name: Path::new(remapped_working_dir_abs) + .join(unmapped_file_path_rel), + } + } + } + } + } + } +} |