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rust/rust/084e6e7320342b603834af97d4e1f521c249fc2f/./compiler/rustc_span/src/lib.rs
blob: d647ec28aae5c52cfd4d8c058d7517d7076ccebe [file]
//! Source positions and related helper functions.
//!
//! Important concepts in this module include:
//!
//! - the *span*, represented by [`SpanData`] and related types;
//! - source code as represented by a [`SourceMap`]; and
//! - interned strings, represented by [`Symbol`]s, with some common symbols available statically
//! in the [`sym`] module.
//!
//! Unlike most compilers, the span contains not only the position in the source code, but also
//! various other metadata, such as the edition and macro hygiene. This metadata is stored in
//! [`SyntaxContext`] and [`ExpnData`].
//!
//! ## Note
//!
//! This API is completely unstable and subject to change.
// tidy-alphabetical-start
#![allow(internal_features)]
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![doc(rust_logo)]
#![feature(array_windows)]
#![feature(cfg_select)]
#![feature(core_io_borrowed_buf)]
#![feature(if_let_guard)]
#![feature(map_try_insert)]
#![feature(negative_impls)]
#![feature(read_buf)]
#![feature(round_char_boundary)]
#![feature(rustc_attrs)]
#![feature(rustdoc_internals)]
// tidy-alphabetical-end
// The code produced by the `Encodable`/`Decodable` derive macros refer to
// `rustc_span::Span{Encoder,Decoder}`. That's fine outside this crate, but doesn't work inside
// this crate without this line making `rustc_span` available.
extern crate self as rustc_span;
use derive_where::derive_where;
use rustc_data_structures::{AtomicRef, outline};
use rustc_macros::{Decodable, Encodable, HashStable_Generic};
use rustc_serialize::opaque::{FileEncoder, MemDecoder};
use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
use tracing::debug;
mod caching_source_map_view;
pub mod source_map;
use source_map::{SourceMap, SourceMapInputs};
pub use self::caching_source_map_view::CachingSourceMapView;
use crate::fatal_error::FatalError;
pub mod edition;
use edition::Edition;
pub mod hygiene;
use hygiene::Transparency;
pub use hygiene::{
DesugaringKind, ExpnData, ExpnHash, ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext,
};
use rustc_data_structures::stable_hasher::HashingControls;
pub mod def_id;
use def_id::{CrateNum, DefId, DefIndex, DefPathHash, LOCAL_CRATE, LocalDefId, StableCrateId};
pub mod edit_distance;
mod span_encoding;
pub use span_encoding::{DUMMY_SP, Span};
pub mod symbol;
pub use symbol::{
ByteSymbol, Ident, MacroRulesNormalizedIdent, Macros20NormalizedIdent, STDLIB_STABLE_CRATES,
Symbol, kw, sym,
};
mod analyze_source_file;
pub mod fatal_error;
pub mod profiling;
use std::borrow::Cow;
use std::cmp::{self, Ordering};
use std::fmt::Display;
use std::hash::Hash;
use std::io::{self, Read};
use std::ops::{Add, Range, Sub};
use std::path::{Path, PathBuf};
use std::str::FromStr;
use std::sync::Arc;
use std::{fmt, iter};
use md5::{Digest, Md5};
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::{FreezeLock, FreezeWriteGuard, Lock};
use rustc_data_structures::unord::UnordMap;
use rustc_hashes::{Hash64, Hash128};
use sha1::Sha1;
use sha2::Sha256;
#[cfg(test)]
mod tests;
/// Per-session global variables: this struct is stored in thread-local storage
/// in such a way that it is accessible without any kind of handle to all
/// threads within the compilation session, but is not accessible outside the
/// session.
pub struct SessionGlobals {
symbol_interner: symbol::Interner,
span_interner: Lock<span_encoding::SpanInterner>,
/// Maps a macro argument token into use of the corresponding metavariable in the macro body.
/// Collisions are possible and processed in `maybe_use_metavar_location` on best effort basis.
metavar_spans: MetavarSpansMap,
hygiene_data: Lock<hygiene::HygieneData>,
/// The session's source map, if there is one. This field should only be
/// used in places where the `Session` is truly not available, such as
/// `<Span as Debug>::fmt`.
source_map: Option<Arc<SourceMap>>,
}
impl SessionGlobals {
pub fn new(
edition: Edition,
extra_symbols: &[&'static str],
sm_inputs: Option<SourceMapInputs>,
) -> SessionGlobals {
SessionGlobals {
symbol_interner: symbol::Interner::with_extra_symbols(extra_symbols),
span_interner: Lock::new(span_encoding::SpanInterner::default()),
metavar_spans: Default::default(),
hygiene_data: Lock::new(hygiene::HygieneData::new(edition)),
source_map: sm_inputs.map(|inputs| Arc::new(SourceMap::with_inputs(inputs))),
}
}
}
pub fn create_session_globals_then<R>(
edition: Edition,
extra_symbols: &[&'static str],
sm_inputs: Option<SourceMapInputs>,
f: impl FnOnce() -> R,
) -> R {
assert!(
!SESSION_GLOBALS.is_set(),
"SESSION_GLOBALS should never be overwritten! \
Use another thread if you need another SessionGlobals"
);
let session_globals = SessionGlobals::new(edition, extra_symbols, sm_inputs);
SESSION_GLOBALS.set(&session_globals, f)
}
pub fn set_session_globals_then<R>(session_globals: &SessionGlobals, f: impl FnOnce() -> R) -> R {
assert!(
!SESSION_GLOBALS.is_set(),
"SESSION_GLOBALS should never be overwritten! \
Use another thread if you need another SessionGlobals"
);
SESSION_GLOBALS.set(session_globals, f)
}
/// No source map.
pub fn create_session_if_not_set_then<R, F>(edition: Edition, f: F) -> R
where
F: FnOnce(&SessionGlobals) -> R,
{
if !SESSION_GLOBALS.is_set() {
let session_globals = SessionGlobals::new(edition, &[], None);
SESSION_GLOBALS.set(&session_globals, || SESSION_GLOBALS.with(f))
} else {
SESSION_GLOBALS.with(f)
}
}
#[inline]
pub fn with_session_globals<R, F>(f: F) -> R
where
F: FnOnce(&SessionGlobals) -> R,
{
SESSION_GLOBALS.with(f)
}
/// Default edition, no source map.
pub fn create_default_session_globals_then<R>(f: impl FnOnce() -> R) -> R {
create_session_globals_then(edition::DEFAULT_EDITION, &[], None, f)
}
// If this ever becomes non thread-local, `decode_syntax_context`
// and `decode_expn_id` will need to be updated to handle concurrent
// deserialization.
scoped_tls::scoped_thread_local!(static SESSION_GLOBALS: SessionGlobals);
#[derive(Default)]
pub struct MetavarSpansMap(FreezeLock<UnordMap<Span, (Span, bool)>>);
impl MetavarSpansMap {
pub fn insert(&self, span: Span, var_span: Span) -> bool {
match self.0.write().try_insert(span, (var_span, false)) {
Ok(_) => true,
Err(entry) => entry.entry.get().0 == var_span,
}
}
/// Read a span and record that it was read.
pub fn get(&self, span: Span) -> Option<Span> {
if let Some(mut mspans) = self.0.try_write() {
if let Some((var_span, read)) = mspans.get_mut(&span) {
*read = true;
Some(*var_span)
} else {
None
}
} else {
if let Some((span, true)) = self.0.read().get(&span) { Some(*span) } else { None }
}
}
/// Freeze the set, and return the spans which have been read.
///
/// After this is frozen, no spans that have not been read can be read.
pub fn freeze_and_get_read_spans(&self) -> UnordMap<Span, Span> {
self.0.freeze().items().filter(|(_, (_, b))| *b).map(|(s1, (s2, _))| (*s1, *s2)).collect()
}
}
#[inline]
pub fn with_metavar_spans<R>(f: impl FnOnce(&MetavarSpansMap) -> R) -> R {
with_session_globals(|session_globals| f(&session_globals.metavar_spans))
}
// 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, Decodable, Encodable)]
pub enum RealFileName {
LocalPath(PathBuf),
/// For remapped paths (namely paths into libstd that have been mapped
/// to the appropriate spot on the local host's file system, and local file
/// system paths that have been remapped with `FilePathMapping`),
Remapped {
/// `local_path` is the (host-dependent) local path to the file. This is
/// None if the file was imported from another crate
local_path: Option<PathBuf>,
/// `virtual_name` is the stable path rustc will store internally within
/// build artifacts.
virtual_name: PathBuf,
},
}
impl Hash for RealFileName {
fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
// To prevent #70924 from happening again we should only hash the
// remapped (virtualized) path if that exists. This is because
// virtualized paths to sysroot crates (/rust/$hash or /rust/$version)
// remain stable even if the corresponding local_path changes
self.remapped_path_if_available().hash(state)
}
}
impl RealFileName {
/// Returns the path suitable for reading from the file system on the local host,
/// if this information exists.
/// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that.
pub fn local_path(&self) -> Option<&Path> {
match self {
RealFileName::LocalPath(p) => Some(p),
RealFileName::Remapped { local_path, virtual_name: _ } => local_path.as_deref(),
}
}
/// Returns the path suitable for reading from the file system on the local host,
/// if this information exists.
/// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that.
pub fn into_local_path(self) -> Option<PathBuf> {
match self {
RealFileName::LocalPath(p) => Some(p),
RealFileName::Remapped { local_path: p, virtual_name: _ } => p,
}
}
/// Returns the path suitable for embedding into build artifacts. This would still
/// be a local path if it has not been remapped. A remapped path will not correspond
/// to a valid file system path: see `local_path_if_available()` for something that
/// is more likely to return paths into the local host file system.
pub fn remapped_path_if_available(&self) -> &Path {
match self {
RealFileName::LocalPath(p)
| RealFileName::Remapped { local_path: _, virtual_name: p } => p,
}
}
/// Returns the path suitable for reading from the file system on the local host,
/// if this information exists. Otherwise returns the remapped name.
/// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that.
pub fn local_path_if_available(&self) -> &Path {
match self {
RealFileName::LocalPath(path)
| RealFileName::Remapped { local_path: None, virtual_name: path }
| RealFileName::Remapped { local_path: Some(path), virtual_name: _ } => path,
}
}
/// Return the path remapped or not depending on the [`FileNameDisplayPreference`].
///
/// For the purpose of this function, local and short preference are equal.
pub fn to_path(&self, display_pref: FileNameDisplayPreference) -> &Path {
match display_pref {
FileNameDisplayPreference::Local | FileNameDisplayPreference::Short => {
self.local_path_if_available()
}
FileNameDisplayPreference::Remapped => self.remapped_path_if_available(),
}
}
pub fn to_string_lossy(&self, display_pref: FileNameDisplayPreference) -> Cow<'_, str> {
match display_pref {
FileNameDisplayPreference::Local => self.local_path_if_available().to_string_lossy(),
FileNameDisplayPreference::Remapped => {
self.remapped_path_if_available().to_string_lossy()
}
FileNameDisplayPreference::Short => self
.local_path_if_available()
.file_name()
.map_or_else(|| "".into(), |f| f.to_string_lossy()),
}
}
}
/// Differentiates between real files and common virtual files.
#[derive(Debug, Eq, PartialEq, Clone, Ord, PartialOrd, Hash, Decodable, Encodable)]
pub enum FileName {
Real(RealFileName),
/// Strings provided as `--cfg [cfgspec]`.
CfgSpec(Hash64),
/// Command line.
Anon(Hash64),
/// Hack in `src/librustc_ast/parse.rs`.
// FIXME(jseyfried)
MacroExpansion(Hash64),
ProcMacroSourceCode(Hash64),
/// Strings provided as crate attributes in the CLI.
CliCrateAttr(Hash64),
/// Custom sources for explicit parser calls from plugins and drivers.
Custom(String),
DocTest(PathBuf, isize),
/// Post-substitution inline assembly from LLVM.
InlineAsm(Hash64),
}
impl From<PathBuf> for FileName {
fn from(p: PathBuf) -> Self {
FileName::Real(RealFileName::LocalPath(p))
}
}
#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug)]
pub enum FileNameEmbeddablePreference {
/// If a remapped path is available, only embed the `virtual_path` and omit the `local_path`.
///
/// Otherwise embed the local-path into the `virtual_path`.
RemappedOnly,
/// Embed the original path as well as its remapped `virtual_path` component if available.
LocalAndRemapped,
}
#[derive(Clone, Copy, Eq, PartialEq, Hash, Debug)]
pub enum FileNameDisplayPreference {
/// Display the path after the application of rewrite rules provided via `--remap-path-prefix`.
/// This is appropriate for paths that get embedded into files produced by the compiler.
Remapped,
/// Display the path before the application of rewrite rules provided via `--remap-path-prefix`.
/// This is appropriate for use in user-facing output (such as diagnostics).
Local,
/// Display only the filename, as a way to reduce the verbosity of the output.
/// This is appropriate for use in user-facing output (such as diagnostics).
Short,
}
pub struct FileNameDisplay<'a> {
inner: &'a FileName,
display_pref: FileNameDisplayPreference,
}
impl fmt::Display for FileNameDisplay<'_> {
fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
use FileName::*;
match *self.inner {
Real(ref name) => {
write!(fmt, "{}", name.to_string_lossy(self.display_pref))
}
CfgSpec(_) => write!(fmt, "<cfgspec>"),
MacroExpansion(_) => write!(fmt, "<macro expansion>"),
Anon(_) => write!(fmt, "<anon>"),
ProcMacroSourceCode(_) => write!(fmt, "<proc-macro source code>"),
CliCrateAttr(_) => write!(fmt, "<crate attribute>"),
Custom(ref s) => write!(fmt, "<{s}>"),
DocTest(ref path, _) => write!(fmt, "{}", path.display()),
InlineAsm(_) => write!(fmt, "<inline asm>"),
}
}
}
impl<'a> FileNameDisplay<'a> {
pub fn to_string_lossy(&self) -> Cow<'a, str> {
match self.inner {
FileName::Real(inner) => inner.to_string_lossy(self.display_pref),
_ => Cow::from(self.to_string()),
}
}
}
impl FileName {
pub fn is_real(&self) -> bool {
use FileName::*;
match *self {
Real(_) => true,
Anon(_)
| MacroExpansion(_)
| ProcMacroSourceCode(_)
| CliCrateAttr(_)
| Custom(_)
| CfgSpec(_)
| DocTest(_, _)
| InlineAsm(_) => false,
}
}
pub fn prefer_remapped_unconditionally(&self) -> FileNameDisplay<'_> {
FileNameDisplay { inner: self, display_pref: FileNameDisplayPreference::Remapped }
}
/// This may include transient local filesystem information.
/// Must not be embedded in build outputs.
pub fn prefer_local(&self) -> FileNameDisplay<'_> {
FileNameDisplay { inner: self, display_pref: FileNameDisplayPreference::Local }
}
pub fn display(&self, display_pref: FileNameDisplayPreference) -> FileNameDisplay<'_> {
FileNameDisplay { inner: self, display_pref }
}
pub fn macro_expansion_source_code(src: &str) -> FileName {
let mut hasher = StableHasher::new();
src.hash(&mut hasher);
FileName::MacroExpansion(hasher.finish())
}
pub fn anon_source_code(src: &str) -> FileName {
let mut hasher = StableHasher::new();
src.hash(&mut hasher);
FileName::Anon(hasher.finish())
}
pub fn proc_macro_source_code(src: &str) -> FileName {
let mut hasher = StableHasher::new();
src.hash(&mut hasher);
FileName::ProcMacroSourceCode(hasher.finish())
}
pub fn cfg_spec_source_code(src: &str) -> FileName {
let mut hasher = StableHasher::new();
src.hash(&mut hasher);
FileName::CfgSpec(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())
}
/// Returns the path suitable for reading from the file system on the local host,
/// if this information exists.
/// Avoid embedding this in build artifacts; see `remapped_path_if_available()` for that.
pub fn into_local_path(self) -> Option<PathBuf> {
match self {
FileName::Real(path) => path.into_local_path(),
FileName::DocTest(path, _) => Some(path),
_ => None,
}
}
}
/// Represents a span.
///
/// Spans represent a region of code, used for error reporting. Positions in spans
/// are *absolute* positions from the beginning of the [`SourceMap`], not positions
/// relative to [`SourceFile`]s. Methods on the `SourceMap` can be used to relate spans back
/// to the original source.
///
/// You must be careful if the span crosses more than one file, since you will not be
/// able to use many of the functions on spans in source_map and you cannot assume
/// that the length of the span is equal to `span.hi - span.lo`; there may be space in the
/// [`BytePos`] range between files.
///
/// `SpanData` is public because `Span` uses a thread-local interner and can't be
/// sent to other threads, but some pieces of performance infra run in a separate thread.
/// Using `Span` is generally preferred.
#[derive(Clone, Copy, Hash, PartialEq, Eq)]
#[derive_where(PartialOrd, Ord)]
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.
#[derive_where(skip)]
// `SyntaxContext` does not implement `Ord`.
// The other fields are enough to determine in-file order.
pub ctxt: SyntaxContext,
#[derive_where(skip)]
// `LocalDefId` does not implement `Ord`.
// The other fields are enough to determine in-file order.
pub parent: Option<LocalDefId>,
}
impl SpanData {
#[inline]
pub fn span(&self) -> Span {
Span::new(self.lo, self.hi, self.ctxt, self.parent)
}
#[inline]
pub fn with_lo(&self, lo: BytePos) -> Span {
Span::new(lo, self.hi, self.ctxt, self.parent)
}
#[inline]
pub fn with_hi(&self, hi: BytePos) -> Span {
Span::new(self.lo, hi, self.ctxt, self.parent)
}
/// Avoid if possible, `Span::map_ctxt` should be preferred.
#[inline]
fn with_ctxt(&self, ctxt: SyntaxContext) -> Span {
Span::new(self.lo, self.hi, ctxt, self.parent)
}
/// Avoid if possible, `Span::with_parent` should be preferred.
#[inline]
fn with_parent(&self, parent: Option<LocalDefId>) -> Span {
Span::new(self.lo, self.hi, self.ctxt, parent)
}
/// Returns `true` if this is a dummy span with any hygienic context.
#[inline]
pub fn is_dummy(self) -> bool {
self.lo.0 == 0 && self.hi.0 == 0
}
/// Returns `true` if `self` fully encloses `other`.
pub fn contains(self, other: Self) -> bool {
self.lo <= other.lo && other.hi <= self.hi
}
}
impl Default for SpanData {
fn default() -> Self {
Self { lo: BytePos(0), hi: BytePos(0), ctxt: SyntaxContext::root(), parent: None }
}
}
impl PartialOrd for Span {
fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
PartialOrd::partial_cmp(&self.data(), &rhs.data())
}
}
impl Ord for Span {
fn cmp(&self, rhs: &Self) -> Ordering {
Ord::cmp(&self.data(), &rhs.data())
}
}
impl Span {
#[inline]
pub fn lo(self) -> BytePos {
self.data().lo
}
#[inline]
pub fn with_lo(self, lo: BytePos) -> Span {
self.data().with_lo(lo)
}
#[inline]
pub fn hi(self) -> BytePos {
self.data().hi
}
#[inline]
pub fn with_hi(self, hi: BytePos) -> Span {
self.data().with_hi(hi)
}
#[inline]
pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span {
self.map_ctxt(|_| ctxt)
}
#[inline]
pub fn is_visible(self, sm: &SourceMap) -> bool {
!self.is_dummy() && sm.is_span_accessible(self)
}
/// Returns whether this span originates in a foreign crate's external macro.
///
/// This is used to test whether a lint should not even begin to figure out whether it should
/// be reported on the current node.
#[inline]
pub fn in_external_macro(self, sm: &SourceMap) -> bool {
self.ctxt().in_external_macro(sm)
}
/// 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, _))
}
/// Return whether `span` is generated by `async` or `await`.
pub fn is_from_async_await(self) -> bool {
matches!(
self.ctxt().outer_expn_data().kind,
ExpnKind::Desugaring(DesugaringKind::Async | DesugaringKind::Await),
)
}
/// Gate suggestions that would not be appropriate in a context the user didn't write.
pub fn can_be_used_for_suggestions(self) -> bool {
!self.from_expansion()
// FIXME: If this span comes from a `derive` macro but it points at code the user wrote,
// the callsite span and the span will be pointing at different places. It also means that
// we can safely provide suggestions on this span.
|| (self.in_derive_expansion()
&& self.parent_callsite().map(|p| (p.lo(), p.hi())) != Some((self.lo(), self.hi())))
}
#[inline]
pub fn with_root_ctxt(lo: BytePos, hi: BytePos) -> Span {
Span::new(lo, hi, SyntaxContext::root(), None)
}
/// Returns a new span representing an empty span at the beginning of this span.
#[inline]
pub fn shrink_to_lo(self) -> Span {
let span = self.data_untracked();
span.with_hi(span.lo)
}
/// Returns a new span representing an empty span at the end of this span.
#[inline]
pub fn shrink_to_hi(self) -> Span {
let span = self.data_untracked();
span.with_lo(span.hi)
}
#[inline]
/// Returns `true` if `hi == lo`.
pub fn is_empty(self) -> bool {
let span = self.data_untracked();
span.hi == span.lo
}
/// Returns `self` if `self` is not the dummy span, and `other` otherwise.
pub fn substitute_dummy(self, other: Span) -> Span {
if self.is_dummy() { other } else { self }
}
/// Returns `true` if `self` fully encloses `other`.
pub fn contains(self, other: Span) -> bool {
let span = self.data();
let other = other.data();
span.contains(other)
}
/// Returns `true` if `self` touches `other`.
pub fn overlaps(self, other: Span) -> bool {
let span = self.data();
let other = other.data();
span.lo < other.hi && other.lo < span.hi
}
/// Returns `true` if `self` touches or adjoins `other`.
pub fn overlaps_or_adjacent(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 `Some(span)`, where the end is trimmed by the start of `other`.
pub fn trim_end(self, other: Span) -> Option<Span> {
let span = self.data();
let other = other.data();
if span.lo < other.lo { Some(span.with_hi(cmp::min(span.hi, other.lo))) } 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 ctxt = self.ctxt();
if !ctxt.is_root() { ctxt.outer_expn_data().call_site.source_callsite() } else { self }
}
/// The `Span` for the tokens in the previous macro expansion from which `self` was generated,
/// if any.
pub fn parent_callsite(self) -> Option<Span> {
let ctxt = self.ctxt();
(!ctxt.is_root()).then(|| ctxt.outer_expn_data().call_site)
}
/// Find the first ancestor span that's contained within `outer`.
///
/// This method traverses the macro expansion ancestors until it finds the first span
/// that's contained within `outer`.
///
/// The span returned by this method may have a different [`SyntaxContext`] than `outer`.
/// If you need to extend the span, use [`find_ancestor_inside_same_ctxt`] instead,
/// because joining spans with different syntax contexts can create unexpected results.
///
/// This is used to find the span of the macro call when a parent expr span, i.e. `outer`, is known.
///
/// [`find_ancestor_inside_same_ctxt`]: Self::find_ancestor_inside_same_ctxt
pub fn find_ancestor_inside(mut self, outer: Span) -> Option<Span> {
while !outer.contains(self) {
self = self.parent_callsite()?;
}
Some(self)
}
/// Find the first ancestor span with the same [`SyntaxContext`] as `other`.
///
/// This method traverses the macro expansion ancestors until it finds a span
/// that has the same [`SyntaxContext`] as `other`.
///
/// Like [`find_ancestor_inside_same_ctxt`], but specifically for when spans might not
/// overlap. Take care when using this, and prefer [`find_ancestor_inside`] or
/// [`find_ancestor_inside_same_ctxt`] when you know that the spans are nested (modulo
/// macro expansion).
///
/// [`find_ancestor_inside`]: Self::find_ancestor_inside
/// [`find_ancestor_inside_same_ctxt`]: Self::find_ancestor_inside_same_ctxt
pub fn find_ancestor_in_same_ctxt(mut self, other: Span) -> Option<Span> {
while !self.eq_ctxt(other) {
self = self.parent_callsite()?;
}
Some(self)
}
/// Find the first ancestor span that's contained within `outer` and
/// has the same [`SyntaxContext`] as `outer`.
///
/// This method traverses the macro expansion ancestors until it finds a span
/// that is both contained within `outer` and has the same [`SyntaxContext`] as `outer`.
///
/// This method is the combination of [`find_ancestor_inside`] and
/// [`find_ancestor_in_same_ctxt`] and should be preferred when extending the returned span.
/// If you do not need to modify the span, use [`find_ancestor_inside`] instead.
///
/// [`find_ancestor_inside`]: Self::find_ancestor_inside
/// [`find_ancestor_in_same_ctxt`]: Self::find_ancestor_in_same_ctxt
pub fn find_ancestor_inside_same_ctxt(mut self, outer: Span) -> Option<Span> {
while !outer.contains(self) || !self.eq_ctxt(outer) {
self = self.parent_callsite()?;
}
Some(self)
}
/// Find the first ancestor span that does not come from an external macro.
///
/// This method traverses the macro expansion ancestors until it finds a span
/// that is either from user-written code or from a local macro (defined in the current crate).
///
/// External macros are those defined in dependencies or the standard library.
/// This method is useful for reporting errors in user-controllable code and avoiding
/// diagnostics inside external macros.
///
/// # See also
///
/// - [`Self::find_ancestor_not_from_macro`]
/// - [`Self::in_external_macro`]
pub fn find_ancestor_not_from_extern_macro(mut self, sm: &SourceMap) -> Option<Span> {
while self.in_external_macro(sm) {
self = self.parent_callsite()?;
}
Some(self)
}
/// Find the first ancestor span that does not come from any macro expansion.
///
/// This method traverses the macro expansion ancestors until it finds a span
/// that originates from user-written code rather than any macro-generated code.
///
/// This method is useful for reporting errors at the exact location users wrote code
/// and providing suggestions at directly editable locations.
///
/// # See also
///
/// - [`Self::find_ancestor_not_from_extern_macro`]
/// - [`Span::from_expansion`]
pub fn find_ancestor_not_from_macro(mut self) -> Option<Span> {
while self.from_expansion() {
self = self.parent_callsite()?;
}
Some(self)
}
/// Edition of the crate from which this span came.
pub fn edition(self) -> edition::Edition {
self.ctxt().edition()
}
/// Is this edition 2015?
#[inline]
pub fn is_rust_2015(self) -> bool {
self.edition().is_rust_2015()
}
/// Are we allowed to use features from the Rust 2018 edition?
#[inline]
pub fn at_least_rust_2018(self) -> bool {
self.edition().at_least_rust_2018()
}
/// Are we allowed to use features from the Rust 2021 edition?
#[inline]
pub fn at_least_rust_2021(self) -> bool {
self.edition().at_least_rust_2021()
}
/// Are we allowed to use features from the Rust 2024 edition?
#[inline]
pub fn at_least_rust_2024(self) -> bool {
self.edition().at_least_rust_2024()
}
/// 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> {
let mut ctxt = self.ctxt();
let mut opt_expn_data = None;
while !ctxt.is_root() {
let expn_data = ctxt.outer_expn_data();
ctxt = expn_data.call_site.ctxt();
opt_expn_data = Some(expn_data);
}
opt_expn_data
}
/// 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
.is_some_and(|features| features.contains(&feature))
}
/// Checks if this span arises from a compiler desugaring of kind `kind`.
pub fn is_desugaring(self, kind: DesugaringKind) -> bool {
match self.ctxt().outer_expn_data().kind {
ExpnKind::Desugaring(k) => k == kind,
_ => false,
}
}
/// Returns the compiler desugaring that created this span, or `None`
/// if this span is not from a desugaring.
pub fn desugaring_kind(self) -> Option<DesugaringKind> {
match self.ctxt().outer_expn_data().kind {
ExpnKind::Desugaring(k) => Some(k),
_ => None,
}
}
/// Checks if a span is "internal" to a macro in which `unsafe`
/// can be used without triggering the `unsafe_code` lint.
/// (that is, a macro marked with `#[allow_internal_unsafe]`).
pub fn allows_unsafe(self) -> bool {
self.ctxt().outer_expn_data().allow_internal_unsafe
}
pub fn macro_backtrace(mut self) -> impl Iterator<Item = ExpnData> {
let mut prev_span = DUMMY_SP;
iter::from_fn(move || {
loop {
let ctxt = self.ctxt();
if ctxt.is_root() {
return None;
}
let expn_data = ctxt.outer_expn_data();
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);
}
}
})
}
/// Splits a span into two composite spans around a certain position.
pub fn split_at(self, pos: u32) -> (Span, Span) {
let len = self.hi().0 - self.lo().0;
debug_assert!(pos <= len);
let split_pos = BytePos(self.lo().0 + pos);
(
Span::new(self.lo(), split_pos, self.ctxt(), self.parent()),
Span::new(split_pos, self.hi(), self.ctxt(), self.parent()),
)
}
/// Check if you can select metavar spans for the given spans to get matching contexts.
fn try_metavars(a: SpanData, b: SpanData, a_orig: Span, b_orig: Span) -> (SpanData, SpanData) {
match with_metavar_spans(|mspans| (mspans.get(a_orig), mspans.get(b_orig))) {
(None, None) => {}
(Some(meta_a), None) => {
let meta_a = meta_a.data();
if meta_a.ctxt == b.ctxt {
return (meta_a, b);
}
}
(None, Some(meta_b)) => {
let meta_b = meta_b.data();
if a.ctxt == meta_b.ctxt {
return (a, meta_b);
}
}
(Some(meta_a), Some(meta_b)) => {
let meta_b = meta_b.data();
if a.ctxt == meta_b.ctxt {
return (a, meta_b);
}
let meta_a = meta_a.data();
if meta_a.ctxt == b.ctxt {
return (meta_a, b);
} else if meta_a.ctxt == meta_b.ctxt {
return (meta_a, meta_b);
}
}
}
(a, b)
}
/// Prepare two spans to a combine operation like `to` or `between`.
fn prepare_to_combine(
a_orig: Span,
b_orig: Span,
) -> Result<(SpanData, SpanData, Option<LocalDefId>), Span> {
let (a, b) = (a_orig.data(), b_orig.data());
if a.ctxt == b.ctxt {
return Ok((a, b, if a.parent == b.parent { a.parent } else { None }));
}
let (a, b) = Span::try_metavars(a, b, a_orig, b_orig);
if a.ctxt == b.ctxt {
return Ok((a, b, if a.parent == b.parent { a.parent } else { None }));
}
// Context mismatches usually happen when procedural macros combine spans copied from
// the macro input with spans produced by the macro (`Span::*_site`).
// In that case we consider the combined span to be produced by the macro and return
// the original macro-produced span as the result.
// Otherwise we just fall back to returning the first span.
// Combining locations typically doesn't make sense in case of context mismatches.
// `is_root` here is a fast path optimization.
let a_is_callsite = a.ctxt.is_root() || a.ctxt == b.span().source_callsite().ctxt();
Err(if a_is_callsite { b_orig } else { a_orig })
}
/// This span, but in a larger context, may switch to the metavariable span if suitable.
pub fn with_neighbor(self, neighbor: Span) -> Span {
match Span::prepare_to_combine(self, neighbor) {
Ok((this, ..)) => this.span(),
Err(_) => self,
}
}
/// Returns a `Span` that would enclose both `self` and `end`.
///
/// Note that this can also be used to extend the span "backwards":
/// `start.to(end)` and `end.to(start)` return the same `Span`.
///
/// ```text
/// ____ ___
/// self lorem ipsum end
/// ^^^^^^^^^^^^^^^^^^^^
/// ```
pub fn to(self, end: Span) -> Span {
match Span::prepare_to_combine(self, end) {
Ok((from, to, parent)) => {
Span::new(cmp::min(from.lo, to.lo), cmp::max(from.hi, to.hi), from.ctxt, parent)
}
Err(fallback) => fallback,
}
}
/// Returns a `Span` between the end of `self` to the beginning of `end`.
///
/// ```text
/// ____ ___
/// self lorem ipsum end
/// ^^^^^^^^^^^^^
/// ```
pub fn between(self, end: Span) -> Span {
match Span::prepare_to_combine(self, end) {
Ok((from, to, parent)) => {
Span::new(cmp::min(from.hi, to.hi), cmp::max(from.lo, to.lo), from.ctxt, parent)
}
Err(fallback) => fallback,
}
}
/// Returns a `Span` from the beginning of `self` until the beginning of `end`.
///
/// ```text
/// ____ ___
/// self lorem ipsum end
/// ^^^^^^^^^^^^^^^^^
/// ```
pub fn until(self, end: Span) -> Span {
match Span::prepare_to_combine(self, end) {
Ok((from, to, parent)) => {
Span::new(cmp::min(from.lo, to.lo), cmp::max(from.lo, to.lo), from.ctxt, parent)
}
Err(fallback) => fallback,
}
}
/// Returns the `Span` within the syntax context of "within". This is useful when
/// "self" is an expansion from a macro variable, since this can be used for
/// providing extra macro expansion context for certain errors.
///
/// ```text
/// macro_rules! m {
/// ($ident:ident) => { ($ident,) }
/// }
///
/// m!(outer_ident);
/// ```
///
/// If "self" is the span of the outer_ident, and "within" is the span of the `($ident,)`
/// expr, then this will return the span of the `$ident` macro variable.
pub fn within_macro(self, within: Span, sm: &SourceMap) -> Option<Span> {
match Span::prepare_to_combine(self, within) {
// Only return something if it doesn't overlap with the original span,
// and the span isn't "imported" (i.e. from unavailable sources).
// FIXME: This does limit the usefulness of the error when the macro is
// from a foreign crate; we could also take into account `-Zmacro-backtrace`,
// which doesn't redact this span (but that would mean passing in even more
// args to this function, lol).
Ok((self_, _, parent))
if self_.hi < self.lo() || self.hi() < self_.lo && !sm.is_imported(within) =>
{
Some(Span::new(self_.lo, self_.hi, self_.ctxt, parent))
}
_ => None,
}
}
pub fn from_inner(self, inner: InnerSpan) -> Span {
let span = self.data();
Span::new(
span.lo + BytePos::from_usize(inner.start),
span.lo + BytePos::from_usize(inner.end),
span.ctxt,
span.parent,
)
}
/// Equivalent of `Span::def_site` from the proc macro API,
/// except that the location is taken from the `self` span.
pub fn with_def_site_ctxt(self, expn_id: ExpnId) -> Span {
self.with_ctxt_from_mark(expn_id, Transparency::Opaque)
}
/// Equivalent of `Span::call_site` from the proc macro API,
/// except that the location is taken from the `self` span.
pub fn with_call_site_ctxt(self, expn_id: ExpnId) -> Span {
self.with_ctxt_from_mark(expn_id, Transparency::Transparent)
}
/// Equivalent of `Span::mixed_site` from the proc macro API,
/// except that the location is taken from the `self` span.
pub fn with_mixed_site_ctxt(self, expn_id: ExpnId) -> Span {
self.with_ctxt_from_mark(expn_id, Transparency::SemiOpaque)
}
/// 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).
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 {
self.map_ctxt(|ctxt| ctxt.apply_mark(expn_id, transparency))
}
#[inline]
pub fn remove_mark(&mut self) -> ExpnId {
let mut mark = ExpnId::root();
*self = self.map_ctxt(|mut ctxt| {
mark = ctxt.remove_mark();
ctxt
});
mark
}
#[inline]
pub fn adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
let mut mark = None;
*self = self.map_ctxt(|mut ctxt| {
mark = ctxt.adjust(expn_id);
ctxt
});
mark
}
#[inline]
pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
let mut mark = None;
*self = self.map_ctxt(|mut ctxt| {
mark = ctxt.normalize_to_macros_2_0_and_adjust(expn_id);
ctxt
});
mark
}
#[inline]
pub fn glob_adjust(&mut self, expn_id: ExpnId, glob_span: Span) -> Option<Option<ExpnId>> {
let mut mark = None;
*self = self.map_ctxt(|mut ctxt| {
mark = ctxt.glob_adjust(expn_id, glob_span);
ctxt
});
mark
}
#[inline]
pub fn reverse_glob_adjust(
&mut self,
expn_id: ExpnId,
glob_span: Span,
) -> Option<Option<ExpnId>> {
let mut mark = None;
*self = self.map_ctxt(|mut ctxt| {
mark = ctxt.reverse_glob_adjust(expn_id, glob_span);
ctxt
});
mark
}
#[inline]
pub fn normalize_to_macros_2_0(self) -> Span {
self.map_ctxt(|ctxt| ctxt.normalize_to_macros_2_0())
}
#[inline]
pub fn normalize_to_macro_rules(self) -> Span {
self.map_ctxt(|ctxt| ctxt.normalize_to_macro_rules())
}
}
impl Default for Span {
fn default() -> Self {
DUMMY_SP
}
}
rustc_index::newtype_index! {
#[orderable]
#[debug_format = "AttrId({})"]
pub struct AttrId {}
}
/// This trait is used to allow encoder specific encodings of certain types.
/// It is similar to rustc_type_ir's TyEncoder.
pub trait SpanEncoder: Encoder {
fn encode_span(&mut self, span: Span);
fn encode_symbol(&mut self, sym: Symbol);
fn encode_byte_symbol(&mut self, byte_sym: ByteSymbol);
fn encode_expn_id(&mut self, expn_id: ExpnId);
fn encode_syntax_context(&mut self, syntax_context: SyntaxContext);
/// As a local identifier, a `CrateNum` is only meaningful within its context, e.g. within a
/// tcx. Therefore, make sure to include the context when encode a `CrateNum`.
fn encode_crate_num(&mut self, crate_num: CrateNum);
fn encode_def_index(&mut self, def_index: DefIndex);
fn encode_def_id(&mut self, def_id: DefId);
}
impl SpanEncoder for FileEncoder {
fn encode_span(&mut self, span: Span) {
let span = span.data();
span.lo.encode(self);
span.hi.encode(self);
}
fn encode_symbol(&mut self, sym: Symbol) {
self.emit_str(sym.as_str());
}
fn encode_byte_symbol(&mut self, byte_sym: ByteSymbol) {
self.emit_byte_str(byte_sym.as_byte_str());
}
fn encode_expn_id(&mut self, _expn_id: ExpnId) {
panic!("cannot encode `ExpnId` with `FileEncoder`");
}
fn encode_syntax_context(&mut self, _syntax_context: SyntaxContext) {
panic!("cannot encode `SyntaxContext` with `FileEncoder`");
}
fn encode_crate_num(&mut self, crate_num: CrateNum) {
self.emit_u32(crate_num.as_u32());
}
fn encode_def_index(&mut self, _def_index: DefIndex) {
panic!("cannot encode `DefIndex` with `FileEncoder`");
}
fn encode_def_id(&mut self, def_id: DefId) {
def_id.krate.encode(self);
def_id.index.encode(self);
}
}
impl<E: SpanEncoder> Encodable<E> for Span {
fn encode(&self, s: &mut E) {
s.encode_span(*self);
}
}
impl<E: SpanEncoder> Encodable<E> for Symbol {
fn encode(&self, s: &mut E) {
s.encode_symbol(*self);
}
}
impl<E: SpanEncoder> Encodable<E> for ByteSymbol {
fn encode(&self, s: &mut E) {
s.encode_byte_symbol(*self);
}
}
impl<E: SpanEncoder> Encodable<E> for ExpnId {
fn encode(&self, s: &mut E) {
s.encode_expn_id(*self)
}
}
impl<E: SpanEncoder> Encodable<E> for SyntaxContext {
fn encode(&self, s: &mut E) {
s.encode_syntax_context(*self)
}
}
impl<E: SpanEncoder> Encodable<E> for CrateNum {
fn encode(&self, s: &mut E) {
s.encode_crate_num(*self)
}
}
impl<E: SpanEncoder> Encodable<E> for DefIndex {
fn encode(&self, s: &mut E) {
s.encode_def_index(*self)
}
}
impl<E: SpanEncoder> Encodable<E> for DefId {
fn encode(&self, s: &mut E) {
s.encode_def_id(*self)
}
}
impl<E: SpanEncoder> Encodable<E> for AttrId {
fn encode(&self, _s: &mut E) {
// A fresh id will be generated when decoding
}
}
/// This trait is used to allow decoder specific encodings of certain types.
/// It is similar to rustc_type_ir's TyDecoder.
pub trait SpanDecoder: Decoder {
fn decode_span(&mut self) -> Span;
fn decode_symbol(&mut self) -> Symbol;
fn decode_byte_symbol(&mut self) -> ByteSymbol;
fn decode_expn_id(&mut self) -> ExpnId;
fn decode_syntax_context(&mut self) -> SyntaxContext;
fn decode_crate_num(&mut self) -> CrateNum;
fn decode_def_index(&mut self) -> DefIndex;
fn decode_def_id(&mut self) -> DefId;
fn decode_attr_id(&mut self) -> AttrId;
}
impl SpanDecoder for MemDecoder<'_> {
fn decode_span(&mut self) -> Span {
let lo = Decodable::decode(self);
let hi = Decodable::decode(self);
Span::new(lo, hi, SyntaxContext::root(), None)
}
fn decode_symbol(&mut self) -> Symbol {
Symbol::intern(self.read_str())
}
fn decode_byte_symbol(&mut self) -> ByteSymbol {
ByteSymbol::intern(self.read_byte_str())
}
fn decode_expn_id(&mut self) -> ExpnId {
panic!("cannot decode `ExpnId` with `MemDecoder`");
}
fn decode_syntax_context(&mut self) -> SyntaxContext {
panic!("cannot decode `SyntaxContext` with `MemDecoder`");
}
fn decode_crate_num(&mut self) -> CrateNum {
CrateNum::from_u32(self.read_u32())
}
fn decode_def_index(&mut self) -> DefIndex {
panic!("cannot decode `DefIndex` with `MemDecoder`");
}
fn decode_def_id(&mut self) -> DefId {
DefId { krate: Decodable::decode(self), index: Decodable::decode(self) }
}
fn decode_attr_id(&mut self) -> AttrId {
panic!("cannot decode `AttrId` with `MemDecoder`");
}
}
impl<D: SpanDecoder> Decodable<D> for Span {
fn decode(s: &mut D) -> Span {
s.decode_span()
}
}
impl<D: SpanDecoder> Decodable<D> for Symbol {
fn decode(s: &mut D) -> Symbol {
s.decode_symbol()
}
}
impl<D: SpanDecoder> Decodable<D> for ByteSymbol {
fn decode(s: &mut D) -> ByteSymbol {
s.decode_byte_symbol()
}
}
impl<D: SpanDecoder> Decodable<D> for ExpnId {
fn decode(s: &mut D) -> ExpnId {
s.decode_expn_id()
}
}
impl<D: SpanDecoder> Decodable<D> for SyntaxContext {
fn decode(s: &mut D) -> SyntaxContext {
s.decode_syntax_context()
}
}
impl<D: SpanDecoder> Decodable<D> for CrateNum {
fn decode(s: &mut D) -> CrateNum {
s.decode_crate_num()
}
}
impl<D: SpanDecoder> Decodable<D> for DefIndex {
fn decode(s: &mut D) -> DefIndex {
s.decode_def_index()
}
}
impl<D: SpanDecoder> Decodable<D> for DefId {
fn decode(s: &mut D) -> DefId {
s.decode_def_id()
}
}
impl<D: SpanDecoder> Decodable<D> for AttrId {
fn decode(s: &mut D) -> AttrId {
s.decode_attr_id()
}
}
impl fmt::Debug for Span {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
// Use the global `SourceMap` to print the span. If that's not
// available, fall back to printing the raw values.
fn fallback(span: Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("Span")
.field("lo", &span.lo())
.field("hi", &span.hi())
.field("ctxt", &span.ctxt())
.finish()
}
if SESSION_GLOBALS.is_set() {
with_session_globals(|session_globals| {
if let Some(source_map) = &session_globals.source_map {
write!(f, "{} ({:?})", source_map.span_to_diagnostic_string(*self), self.ctxt())
} else {
fallback(*self, f)
}
})
} else {
fallback(*self, f)
}
}
}
impl fmt::Debug for SpanData {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.span(), f)
}
}
/// Identifies an offset of a multi-byte character in a `SourceFile`.
#[derive(Copy, Clone, Encodable, Decodable, Eq, PartialEq, Debug, HashStable_Generic)]
pub struct MultiByteChar {
/// The relative offset of the character in the `SourceFile`.
pub pos: RelativeBytePos,
/// The number of bytes, `>= 2`.
pub bytes: u8,
}
/// Identifies an offset of a character that was normalized away from `SourceFile`.
#[derive(Copy, Clone, Encodable, Decodable, Eq, PartialEq, Debug, HashStable_Generic)]
pub struct NormalizedPos {
/// The relative offset of the character in the `SourceFile`.
pub pos: RelativeBytePos,
/// 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,
/// Index of the file inside metadata.
metadata_index: u32,
},
}
/// 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(Arc<String>),
/// No attempt has been made to load the external source.
AbsentOk,
/// A failed attempt has been made to load the external source.
AbsentErr,
}
impl ExternalSource {
pub fn get_source(&self) -> Option<&str> {
match self {
ExternalSource::Foreign { kind: ExternalSourceKind::Present(src), .. } => Some(src),
_ => None,
}
}
}
#[derive(Debug)]
pub struct OffsetOverflowError;
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Encodable, Decodable)]
#[derive(HashStable_Generic)]
pub enum SourceFileHashAlgorithm {
Md5,
Sha1,
Sha256,
Blake3,
}
impl Display for SourceFileHashAlgorithm {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(match self {
Self::Md5 => "md5",
Self::Sha1 => "sha1",
Self::Sha256 => "sha256",
Self::Blake3 => "blake3",
})
}
}
impl FromStr for SourceFileHashAlgorithm {
type Err = ();
fn from_str(s: &str) -> Result<SourceFileHashAlgorithm, ()> {
match s {
"md5" => Ok(SourceFileHashAlgorithm::Md5),
"sha1" => Ok(SourceFileHashAlgorithm::Sha1),
"sha256" => Ok(SourceFileHashAlgorithm::Sha256),
"blake3" => Ok(SourceFileHashAlgorithm::Blake3),
_ => Err(()),
}
}
}
/// The hash of the on-disk source file used for debug info and cargo freshness checks.
#[derive(Copy, Clone, PartialEq, Eq, Debug, Hash)]
#[derive(HashStable_Generic, Encodable, Decodable)]
pub struct SourceFileHash {
pub kind: SourceFileHashAlgorithm,
value: [u8; 32],
}
impl Display for SourceFileHash {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(f, "{}=", self.kind)?;
for byte in self.value[0..self.hash_len()].into_iter() {
write!(f, "{byte:02x}")?;
}
Ok(())
}
}
impl SourceFileHash {
pub fn new_in_memory(kind: SourceFileHashAlgorithm, src: impl AsRef<[u8]>) -> SourceFileHash {
let mut hash = SourceFileHash { kind, value: Default::default() };
let len = hash.hash_len();
let value = &mut hash.value[..len];
let data = src.as_ref();
match kind {
SourceFileHashAlgorithm::Md5 => {
value.copy_from_slice(&Md5::digest(data));
}
SourceFileHashAlgorithm::Sha1 => {
value.copy_from_slice(&Sha1::digest(data));
}
SourceFileHashAlgorithm::Sha256 => {
value.copy_from_slice(&Sha256::digest(data));
}
SourceFileHashAlgorithm::Blake3 => value.copy_from_slice(blake3::hash(data).as_bytes()),
};
hash
}
pub fn new(kind: SourceFileHashAlgorithm, src: impl Read) -> Result<SourceFileHash, io::Error> {
let mut hash = SourceFileHash { kind, value: Default::default() };
let len = hash.hash_len();
let value = &mut hash.value[..len];
// Buffer size is the recommended amount to fully leverage SIMD instructions on AVX-512 as per
// blake3 documentation.
let mut buf = vec![0; 16 * 1024];
fn digest<T>(
mut hasher: T,
mut update: impl FnMut(&mut T, &[u8]),
finish: impl FnOnce(T, &mut [u8]),
mut src: impl Read,
buf: &mut [u8],
value: &mut [u8],
) -> Result<(), io::Error> {
loop {
let bytes_read = src.read(buf)?;
if bytes_read == 0 {
break;
}
update(&mut hasher, &buf[0..bytes_read]);
}
finish(hasher, value);
Ok(())
}
match kind {
SourceFileHashAlgorithm::Sha256 => {
digest(
Sha256::new(),
|h, b| {
h.update(b);
},
|h, out| out.copy_from_slice(&h.finalize()),
src,
&mut buf,
value,
)?;
}
SourceFileHashAlgorithm::Sha1 => {
digest(
Sha1::new(),
|h, b| {
h.update(b);
},
|h, out| out.copy_from_slice(&h.finalize()),
src,
&mut buf,
value,
)?;
}
SourceFileHashAlgorithm::Md5 => {
digest(
Md5::new(),
|h, b| {
h.update(b);
},
|h, out| out.copy_from_slice(&h.finalize()),
src,
&mut buf,
value,
)?;
}
SourceFileHashAlgorithm::Blake3 => {
digest(
blake3::Hasher::new(),
|h, b| {
h.update(b);
},
|h, out| out.copy_from_slice(h.finalize().as_bytes()),
src,
&mut buf,
value,
)?;
}
}
Ok(hash)
}
/// Check if the stored hash matches the hash of the string.
pub fn matches(&self, src: &str) -> bool {
Self::new_in_memory(self.kind, src.as_bytes()) == *self
}
/// The bytes of the hash.
pub fn hash_bytes(&self) -> &[u8] {
let len = self.hash_len();
&self.value[..len]
}
fn hash_len(&self) -> usize {
match self.kind {
SourceFileHashAlgorithm::Md5 => 16,
SourceFileHashAlgorithm::Sha1 => 20,
SourceFileHashAlgorithm::Sha256 | SourceFileHashAlgorithm::Blake3 => 32,
}
}
}
#[derive(Clone)]
pub enum SourceFileLines {
/// The source file lines, in decoded (random-access) form.
Lines(Vec<RelativeBytePos>),
/// The source file lines, in undecoded difference list form.
Diffs(SourceFileDiffs),
}
impl SourceFileLines {
pub fn is_lines(&self) -> bool {
matches!(self, SourceFileLines::Lines(_))
}
}
/// The source file lines in difference list form. This matches the form
/// used within metadata, which saves space by exploiting the fact that the
/// lines list is sorted and individual lines are usually not that long.
///
/// We read it directly from metadata and only decode it into `Lines` form
/// when necessary. This is a significant performance win, especially for
/// small crates where very little of `std`'s metadata is used.
#[derive(Clone)]
pub struct SourceFileDiffs {
/// Always 1, 2, or 4. Always as small as possible, while being big
/// enough to hold the length of the longest line in the source file.
/// The 1 case is by far the most common.
bytes_per_diff: usize,
/// The number of diffs encoded in `raw_diffs`. Always one less than
/// the number of lines in the source file.
num_diffs: usize,
/// The diffs in "raw" form. Each segment of `bytes_per_diff` length
/// encodes one little-endian diff. Note that they aren't LEB128
/// encoded. This makes for much faster decoding. Besides, the
/// bytes_per_diff==1 case is by far the most common, and LEB128
/// encoding has no effect on that case.
raw_diffs: Vec<u8>,
}
/// A single source in the [`SourceMap`].
pub struct SourceFile {
/// The name of the file that the source came from. Source that doesn't
/// originate from files has names between angle brackets by convention
/// (e.g., `<anon>`).
pub name: FileName,
/// The complete source code.
pub src: Option<Arc<String>>,
/// The source code's hash.
pub src_hash: SourceFileHash,
/// Used to enable cargo to use checksums to check if a crate is fresh rather
/// than mtimes. This might be the same as `src_hash`, and if the requested algorithm
/// is identical we won't compute it twice.
pub checksum_hash: Option<SourceFileHash>,
/// The external source code (used for external crates, which will have a `None`
/// value as `self.src`.
pub external_src: FreezeLock<ExternalSource>,
/// The start position of this source in the `SourceMap`.
pub start_pos: BytePos,
/// The byte length of this source.
pub source_len: RelativeBytePos,
/// Locations of lines beginnings in the source code.
pub lines: FreezeLock<SourceFileLines>,
/// Locations of multi-byte characters in the source code.
pub multibyte_chars: Vec<MultiByteChar>,
/// Locations of characters removed during normalization.
pub normalized_pos: Vec<NormalizedPos>,
/// A hash of the filename & crate-id, used for uniquely identifying source
/// files within the crate graph and for speeding up hashing in incremental
/// compilation.
pub stable_id: StableSourceFileId,
/// Indicates which crate this `SourceFile` was imported from.
pub cnum: CrateNum,
}
impl Clone for SourceFile {
fn clone(&self) -> Self {
Self {
name: self.name.clone(),
src: self.src.clone(),
src_hash: self.src_hash,
checksum_hash: self.checksum_hash,
external_src: self.external_src.clone(),
start_pos: self.start_pos,
source_len: self.source_len,
lines: self.lines.clone(),
multibyte_chars: self.multibyte_chars.clone(),
normalized_pos: self.normalized_pos.clone(),
stable_id: self.stable_id,
cnum: self.cnum,
}
}
}
impl<S: SpanEncoder> Encodable<S> for SourceFile {
fn encode(&self, s: &mut S) {
self.name.encode(s);
self.src_hash.encode(s);
self.checksum_hash.encode(s);
// Do not encode `start_pos` as it's global state for this session.
self.source_len.encode(s);
// We are always in `Lines` form by the time we reach here.
assert!(self.lines.read().is_lines());
let lines = self.lines();
// Store the length.
s.emit_u32(lines.len() as u32);
// Compute and store the difference list.
if lines.len() != 0 {
let max_line_length = if lines.len() == 1 {
0
} else {
lines
.array_windows()
.map(|&[fst, snd]| snd - fst)
.map(|bp| bp.to_usize())
.max()
.unwrap()
};
let bytes_per_diff: usize = match max_line_length {
0..=0xFF => 1,
0x100..=0xFFFF => 2,
_ => 4,
};
// Encode the number of bytes used per diff.
s.emit_u8(bytes_per_diff as u8);
// Encode the first element.
assert_eq!(lines[0], RelativeBytePos(0));
// Encode the difference list.
let diff_iter = lines.array_windows().map(|&[fst, snd]| snd - fst);
let num_diffs = lines.len() - 1;
let mut raw_diffs;
match bytes_per_diff {
1 => {
raw_diffs = Vec::with_capacity(num_diffs);
for diff in diff_iter {
raw_diffs.push(diff.0 as u8);
}
}
2 => {
raw_diffs = Vec::with_capacity(bytes_per_diff * num_diffs);
for diff in diff_iter {
raw_diffs.extend_from_slice(&(diff.0 as u16).to_le_bytes());
}
}
4 => {
raw_diffs = Vec::with_capacity(bytes_per_diff * num_diffs);
for diff in diff_iter {
raw_diffs.extend_from_slice(&(diff.0).to_le_bytes());
}
}
_ => unreachable!(),
}
s.emit_raw_bytes(&raw_diffs);
}
self.multibyte_chars.encode(s);
self.stable_id.encode(s);
self.normalized_pos.encode(s);
self.cnum.encode(s);
}
}
impl<D: SpanDecoder> Decodable<D> for SourceFile {
fn decode(d: &mut D) -> SourceFile {
let name: FileName = Decodable::decode(d);
let src_hash: SourceFileHash = Decodable::decode(d);
let checksum_hash: Option<SourceFileHash> = Decodable::decode(d);
let source_len: RelativeBytePos = Decodable::decode(d);
let lines = {
let num_lines: u32 = Decodable::decode(d);
if num_lines > 0 {
// Read the number of bytes used per diff.
let bytes_per_diff = d.read_u8() as usize;
// Read the difference list.
let num_diffs = num_lines as usize - 1;
let raw_diffs = d.read_raw_bytes(bytes_per_diff * num_diffs).to_vec();
SourceFileLines::Diffs(SourceFileDiffs { bytes_per_diff, num_diffs, raw_diffs })
} else {
SourceFileLines::Lines(vec![])
}
};
let multibyte_chars: Vec<MultiByteChar> = Decodable::decode(d);
let stable_id = Decodable::decode(d);
let normalized_pos: Vec<NormalizedPos> = Decodable::decode(d);
let cnum: CrateNum = Decodable::decode(d);
SourceFile {
name,
start_pos: BytePos::from_u32(0),
source_len,
src: None,
src_hash,
checksum_hash,
// Unused - the metadata decoder will construct
// a new SourceFile, filling in `external_src` properly
external_src: FreezeLock::frozen(ExternalSource::Unneeded),
lines: FreezeLock::new(lines),
multibyte_chars,
normalized_pos,
stable_id,
cnum,
}
}
}
impl fmt::Debug for SourceFile {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(fmt, "SourceFile({:?})", self.name)
}
}
/// 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).
///
/// It is a hash value (so we can efficiently consume it when stable-hashing
/// spans) that consists of the `FileName` and the `StableCrateId` of the crate
/// the source file is from. The crate id is needed because sometimes the
/// `FileName` is not unique within the crate graph (think `src/lib.rs`, for
/// example).
///
/// The way the crate-id part is handled is a bit special: source files of the
/// local crate are hashed as `(filename, None)`, while source files from
/// upstream crates have a hash of `(filename, Some(stable_crate_id))`. This
/// is because SourceFiles for the local crate are allocated very early in the
/// compilation process when the `StableCrateId` is not yet known. If, due to
/// some refactoring of the compiler, the `StableCrateId` of the local crate
/// were to become available, it would be better to uniformly make this a
/// hash of `(filename, stable_crate_id)`.
///
/// When `SourceFile`s are exported in crate metadata, the `StableSourceFileId`
/// is updated to incorporate the `StableCrateId` of the exporting crate.
#[derive(
Debug,
Clone,
Copy,
Hash,
PartialEq,
Eq,
HashStable_Generic,
Encodable,
Decodable,
Default,
PartialOrd,
Ord
)]
pub struct StableSourceFileId(Hash128);
impl StableSourceFileId {
fn from_filename_in_current_crate(filename: &FileName) -> Self {
Self::from_filename_and_stable_crate_id(filename, None)
}
pub fn from_filename_for_export(
filename: &FileName,
local_crate_stable_crate_id: StableCrateId,
) -> Self {
Self::from_filename_and_stable_crate_id(filename, Some(local_crate_stable_crate_id))
}
fn from_filename_and_stable_crate_id(
filename: &FileName,
stable_crate_id: Option<StableCrateId>,
) -> Self {
let mut hasher = StableHasher::new();
filename.hash(&mut hasher);
stable_crate_id.hash(&mut hasher);
StableSourceFileId(hasher.finish())
}
}
impl SourceFile {
const MAX_FILE_SIZE: u32 = u32::MAX - 1;
pub fn new(
name: FileName,
mut src: String,
hash_kind: SourceFileHashAlgorithm,
checksum_hash_kind: Option<SourceFileHashAlgorithm>,
) -> Result<Self, OffsetOverflowError> {
// Compute the file hash before any normalization.
let src_hash = SourceFileHash::new_in_memory(hash_kind, src.as_bytes());
let checksum_hash = checksum_hash_kind.map(|checksum_hash_kind| {
if checksum_hash_kind == hash_kind {
src_hash
} else {
SourceFileHash::new_in_memory(checksum_hash_kind, src.as_bytes())
}
});
let normalized_pos = normalize_src(&mut src);
let stable_id = StableSourceFileId::from_filename_in_current_crate(&name);
let source_len = src.len();
let source_len = u32::try_from(source_len).map_err(|_| OffsetOverflowError)?;
if source_len > Self::MAX_FILE_SIZE {
return Err(OffsetOverflowError);
}
let (lines, multibyte_chars) = analyze_source_file::analyze_source_file(&src);
Ok(SourceFile {
name,
src: Some(Arc::new(src)),
src_hash,
checksum_hash,
external_src: FreezeLock::frozen(ExternalSource::Unneeded),
start_pos: BytePos::from_u32(0),
source_len: RelativeBytePos::from_u32(source_len),
lines: FreezeLock::frozen(SourceFileLines::Lines(lines)),
multibyte_chars,
normalized_pos,
stable_id,
cnum: LOCAL_CRATE,
})
}
/// This converts the `lines` field to contain `SourceFileLines::Lines` if needed and freezes
/// it.
fn convert_diffs_to_lines_frozen(&self) {
let mut guard = if let Some(guard) = self.lines.try_write() { guard } else { return };
let SourceFileDiffs { bytes_per_diff, num_diffs, raw_diffs } = match &*guard {
SourceFileLines::Diffs(diffs) => diffs,
SourceFileLines::Lines(..) => {
FreezeWriteGuard::freeze(guard);
return;
}
};
// Convert from "diffs" form to "lines" form.
let num_lines = num_diffs + 1;
let mut lines = Vec::with_capacity(num_lines);
let mut line_start = RelativeBytePos(0);
lines.push(line_start);
assert_eq!(*num_diffs, raw_diffs.len() / bytes_per_diff);
match bytes_per_diff {
1 => {
lines.extend(raw_diffs.into_iter().map(|&diff| {
line_start = line_start + RelativeBytePos(diff as u32);
line_start
}));
}
2 => {
lines.extend((0..*num_diffs).map(|i| {
let pos = bytes_per_diff * i;
let bytes = [raw_diffs[pos], raw_diffs[pos + 1]];
let diff = u16::from_le_bytes(bytes);
line_start = line_start + RelativeBytePos(diff as u32);
line_start
}));
}
4 => {
lines.extend((0..*num_diffs).map(|i| {
let pos = bytes_per_diff * i;
let bytes = [
raw_diffs[pos],
raw_diffs[pos + 1],
raw_diffs[pos + 2],
raw_diffs[pos + 3],
];
let diff = u32::from_le_bytes(bytes);
line_start = line_start + RelativeBytePos(diff);
line_start
}));
}
_ => unreachable!(),
}
*guard = SourceFileLines::Lines(lines);
FreezeWriteGuard::freeze(guard);
}
pub fn lines(&self) -> &[RelativeBytePos] {
if let Some(SourceFileLines::Lines(lines)) = self.lines.get() {
return &lines[..];
}
outline(|| {
self.convert_diffs_to_lines_frozen();
if let Some(SourceFileLines::Lines(lines)) = self.lines.get() {
return &lines[..];
}
unreachable!()
})
}
/// Returns the `BytePos` of the beginning of the current line.
pub fn line_begin_pos(&self, pos: BytePos) -> BytePos {
let pos = self.relative_position(pos);
let line_index = self.lookup_line(pos).unwrap();
let line_start_pos = self.lines()[line_index];
self.absolute_position(line_start_pos)
}
/// 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 !self.external_src.is_frozen() {
let src = get_src();
let src = src.and_then(|mut src| {
// The src_hash needs to be computed on the pre-normalized src.
self.src_hash.matches(&src).then(|| {
normalize_src(&mut src);
src
})
});
self.external_src.try_write().map(|mut external_src| {
if let ExternalSource::Foreign {
kind: src_kind @ ExternalSourceKind::AbsentOk,
..
} = &mut *external_src
{
*src_kind = if let Some(src) = src {
ExternalSourceKind::Present(Arc::new(src))
} else {
ExternalSourceKind::AbsentErr
};
} else {
panic!("unexpected state {:?}", *external_src)
}
// Freeze this so we don't try to load the source again.
FreezeWriteGuard::freeze(external_src)
});
}
self.src.is_some() || self.external_src.read().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).copied()?;
line.to_usize()
};
if let Some(ref src) = self.src {
Some(Cow::from(get_until_newline(src, begin)))
} else {
self.external_src
.borrow()
.get_source()
.map(|src| Cow::Owned(String::from(get_until_newline(src, begin))))
}
}
pub fn is_real_file(&self) -> bool {
self.name.is_real()
}
#[inline]
pub fn is_imported(&self) -> bool {
self.src.is_none()
}
pub fn count_lines(&self) -> usize {
self.lines().len()
}
#[inline]
pub fn absolute_position(&self, pos: RelativeBytePos) -> BytePos {
BytePos::from_u32(pos.to_u32() + self.start_pos.to_u32())
}
#[inline]
pub fn relative_position(&self, pos: BytePos) -> RelativeBytePos {
RelativeBytePos::from_u32(pos.to_u32() - self.start_pos.to_u32())
}
#[inline]
pub fn end_position(&self) -> BytePos {
self.absolute_position(self.source_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: RelativeBytePos) -> Option<usize> {
self.lines().partition_point(|x| x <= &pos).checked_sub(1)
}
pub fn line_bounds(&self, line_index: usize) -> Range<BytePos> {
if self.is_empty() {
return self.start_pos..self.start_pos;
}
let lines = self.lines();
assert!(line_index < lines.len());
if line_index == (lines.len() - 1) {
self.absolute_position(lines[line_index])..self.end_position()
} else {
self.absolute_position(lines[line_index])..self.absolute_position(lines[line_index + 1])
}
}
/// Returns whether or not the file contains the given `SourceMap` byte
/// position. The position one past the end of the file is considered to be
/// contained by the file. This implies that files for which `is_empty`
/// returns true still contain one byte position according to this function.
#[inline]
pub fn contains(&self, byte_pos: BytePos) -> bool {
byte_pos >= self.start_pos && byte_pos <= self.end_position()
}
#[inline]
pub fn is_empty(&self) -> bool {
self.source_len.to_u32() == 0
}
/// 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) -> RelativeBytePos {
let pos = self.relative_position(pos);
// 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(0) => 0,
Err(i) => self.normalized_pos[i - 1].diff,
};
RelativeBytePos::from_u32(pos.0 + diff)
}
/// Calculates a normalized byte position from a byte offset relative to the
/// start of the file.
///
/// When we get an inline assembler error from LLVM during codegen, we
/// import the expanded assembly code as a new `SourceFile`, which can then
/// be used for error reporting with spans. However the byte offsets given
/// to us by LLVM are relative to the start of the original buffer, not the
/// normalized one. Hence we need to convert those offsets to the normalized
/// form when constructing spans.
pub fn normalized_byte_pos(&self, offset: u32) -> BytePos {
let diff = match self
.normalized_pos
.binary_search_by(|np| (np.pos.0 + np.diff).cmp(&(self.start_pos.0 + offset)))
{
Ok(i) => self.normalized_pos[i].diff,
Err(0) => 0,
Err(i) => self.normalized_pos[i - 1].diff,
};
BytePos::from_u32(self.start_pos.0 + offset - diff)
}
/// Converts an relative `RelativeBytePos` to a `CharPos` relative to the `SourceFile`.
fn bytepos_to_file_charpos(&self, bpos: RelativeBytePos) -> CharPos {
// The number of extra bytes due to multibyte chars in the `SourceFile`.
let mut total_extra_bytes = 0;
for mbc in self.multibyte_chars.iter() {
debug!("{}-byte char at {:?}", mbc.bytes, mbc.pos);
if mbc.pos < bpos {
// Every character is at least one byte, so we only
// count the actual extra bytes.
total_extra_bytes += mbc.bytes as u32 - 1;
// We should never see a byte position in the middle of a
// character.
assert!(bpos.to_u32() >= mbc.pos.to_u32() + mbc.bytes as u32);
} else {
break;
}
}
assert!(total_extra_bytes <= bpos.to_u32());
CharPos(bpos.to_usize() - total_extra_bytes as usize)
}
/// Looks up the file's (1-based) line number and (0-based `CharPos`) column offset, for a
/// given `RelativeBytePos`.
fn lookup_file_pos(&self, pos: RelativeBytePos) -> (usize, CharPos) {
let chpos = self.bytepos_to_file_charpos(pos);
match self.lookup_line(pos) {
Some(a) => {
let line = a + 1; // Line numbers start at 1
let linebpos = self.lines()[a];
let linechpos = self.bytepos_to_file_charpos(linebpos);
let col = chpos - linechpos;
debug!("byte pos {:?} is on the line at byte pos {:?}", pos, linebpos);
debug!("char pos {:?} is on the line at char pos {:?}", chpos, linechpos);
debug!("byte is on line: {}", line);
assert!(chpos >= linechpos);
(line, col)
}
None => (0, chpos),
}
}
/// Looks up the file's (1-based) line number, (0-based `CharPos`) column offset, and (0-based)
/// column offset when displayed, for a given `BytePos`.
pub fn lookup_file_pos_with_col_display(&self, pos: BytePos) -> (usize, CharPos, usize) {
let pos = self.relative_position(pos);
let (line, col_or_chpos) = self.lookup_file_pos(pos);
if line > 0 {
let Some(code) = self.get_line(line - 1) else {
// If we don't have the code available, it is ok as a fallback to return the bytepos
// instead of the "display" column, which is only used to properly show underlines
// in the terminal.
// FIXME: we'll want better handling of this in the future for the sake of tools
// that want to use the display col instead of byte offsets to modify Rust code, but
// that is a problem for another day, the previous code was already incorrect for
// both displaying *and* third party tools using the json output naïvely.
tracing::info!("couldn't find line {line} {:?}", self.name);
return (line, col_or_chpos, col_or_chpos.0);
};
let display_col = code.chars().take(col_or_chpos.0).map(|ch| char_width(ch)).sum();
(line, col_or_chpos, display_col)
} else {
// This is never meant to happen?
(0, col_or_chpos, col_or_chpos.0)
}
}
}
pub fn char_width(ch: char) -> usize {
// FIXME: `unicode_width` sometimes disagrees with terminals on how wide a `char` is. For now,
// just accept that sometimes the code line will be longer than desired.
match ch {
'\t' => 4,
// Keep the following list in sync with `rustc_errors::emitter::OUTPUT_REPLACEMENTS`. These
// are control points that we replace before printing with a visible codepoint for the sake
// of being able to point at them with underlines.
'\u{0000}' | '\u{0001}' | '\u{0002}' | '\u{0003}' | '\u{0004}' | '\u{0005}'
| '\u{0006}' | '\u{0007}' | '\u{0008}' | '\u{000B}' | '\u{000C}' | '\u{000D}'
| '\u{000E}' | '\u{000F}' | '\u{0010}' | '\u{0011}' | '\u{0012}' | '\u{0013}'
| '\u{0014}' | '\u{0015}' | '\u{0016}' | '\u{0017}' | '\u{0018}' | '\u{0019}'
| '\u{001A}' | '\u{001B}' | '\u{001C}' | '\u{001D}' | '\u{001E}' | '\u{001F}'
| '\u{007F}' | '\u{202A}' | '\u{202B}' | '\u{202D}' | '\u{202E}' | '\u{2066}'
| '\u{2067}' | '\u{2068}' | '\u{202C}' | '\u{2069}' => 1,
_ => unicode_width::UnicodeWidthChar::width(ch).unwrap_or(1),
}
}
pub fn str_width(s: &str) -> usize {
s.chars().map(char_width).sum()
}
/// Normalizes the source code and records the normalizations.
fn normalize_src(src: &mut String) -> Vec<NormalizedPos> {
let mut normalized_pos = vec![];
remove_bom(src, &mut normalized_pos);
normalize_newlines(src, &mut normalized_pos);
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: RelativeBytePos(0), diff: 3 });
}
}
/// Replaces `\r\n` with `\n` in-place in `src`.
///
/// Leaves any occurrences of lone `\r` unchanged.
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: RelativeBytePos::from_usize(cursor + 1),
diff: original_gap + gap_len as u32,
});
}
// Account for removed `\r`.
// After `set_len`, `buf` is guaranteed to contain utf-8 again.
let new_len = buf.len() - gap_len;
unsafe {
buf.set_len(new_len);
*src = String::from_utf8_unchecked(buf);
}
fn find_crlf(src: &[u8]) -> Option<usize> {
let mut search_idx = 0;
while let Some(idx) = find_cr(&src[search_idx..]) {
if src[search_idx..].get(idx + 1) != Some(&b'\n') {
search_idx += idx + 1;
continue;
}
return Some(search_idx + idx);
}
None
}
fn find_cr(src: &[u8]) -> Option<usize> {
src.iter().position(|&b| b == b'\r')
}
}
// _____________________________________________________________________________
// Pos, BytePos, CharPos
//
pub trait Pos {
fn from_usize(n: usize) -> Self;
fn to_usize(&self) -> usize;
fn from_u32(n: u32) -> Self;
fn to_u32(&self) -> u32;
}
macro_rules! impl_pos {
(
$(
$(#[$attr:meta])*
$vis:vis struct $ident:ident($inner_vis:vis $inner_ty:ty);
)*
) => {
$(
$(#[$attr])*
$vis struct $ident($inner_vis $inner_ty);
impl Pos for $ident {
#[inline(always)]
fn from_usize(n: usize) -> $ident {
$ident(n as $inner_ty)
}
#[inline(always)]
fn to_usize(&self) -> usize {
self.0 as usize
}
#[inline(always)]
fn from_u32(n: u32) -> $ident {
$ident(n as $inner_ty)
}
#[inline(always)]
fn to_u32(&self) -> u32 {
self.0 as u32
}
}
impl Add for $ident {
type Output = $ident;
#[inline(always)]
fn add(self, rhs: $ident) -> $ident {
$ident(self.0 + rhs.0)
}
}
impl Sub for $ident {
type Output = $ident;
#[inline(always)]
fn sub(self, rhs: $ident) -> $ident {
$ident(self.0 - rhs.0)
}
}
)*
};
}
impl_pos! {
/// A byte offset.
///
/// Keep this small (currently 32-bits), as AST contains a lot of them.
#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)]
pub struct BytePos(pub u32);
/// A byte offset relative to file beginning.
#[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Ord, Debug)]
pub struct RelativeBytePos(pub u32);
/// A character offset.
///
/// Because of multibyte UTF-8 characters, a byte offset
/// is not equivalent to a character offset. The [`SourceMap`] will convert [`BytePos`]
/// values to `CharPos` values as necessary.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug)]
pub struct CharPos(pub usize);
}
impl<S: Encoder> Encodable<S> for BytePos {
fn encode(&self, s: &mut S) {
s.emit_u32(self.0);
}
}
impl<D: Decoder> Decodable<D> for BytePos {
fn decode(d: &mut D) -> BytePos {
BytePos(d.read_u32())
}
}
impl<H: HashStableContext> HashStable<H> for RelativeBytePos {
fn hash_stable(&self, hcx: &mut H, hasher: &mut StableHasher) {
self.0.hash_stable(hcx, hasher);
}
}
impl<S: Encoder> Encodable<S> for RelativeBytePos {
fn encode(&self, s: &mut S) {
s.emit_u32(self.0);
}
}
impl<D: Decoder> Decodable<D> for RelativeBytePos {
fn decode(d: &mut D) -> RelativeBytePos {
RelativeBytePos(d.read_u32())
}
}
// _____________________________________________________________________________
// Loc, SourceFileAndLine, SourceFileAndBytePos
//
/// A source code location used for error reporting.
#[derive(Debug, Clone)]
pub struct Loc {
/// Information about the original source.
pub file: Arc<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: Arc<SourceFile>,
/// Index of line, starting from 0.
pub line: usize,
}
#[derive(Debug)]
pub struct SourceFileAndBytePos {
pub sf: Arc<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: Arc<SourceFile>,
pub lines: Vec<LineInfo>,
}
pub static SPAN_TRACK: AtomicRef<fn(LocalDefId)> = AtomicRef::new(&((|_| {}) as fn(_)));
// _____________________________________________________________________________
// SpanLinesError, SpanSnippetError, DistinctSources, MalformedSourceMapPositions
//
pub type FileLinesResult = Result<FileLines, SpanLinesError>;
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum SpanLinesError {
DistinctSources(Box<DistinctSources>),
}
#[derive(Clone, PartialEq, Eq, Debug)]
pub enum SpanSnippetError {
IllFormedSpan(Span),
DistinctSources(Box<DistinctSources>),
MalformedForSourcemap(MalformedSourceMapPositions),
SourceNotAvailable { filename: FileName },
}
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct DistinctSources {
pub begin: (FileName, BytePos),
pub end: (FileName, BytePos),
}
#[derive(Clone, PartialEq, Eq, Debug)]
pub struct MalformedSourceMapPositions {
pub name: FileName,
pub source_len: usize,
pub begin_pos: BytePos,
pub end_pos: BytePos,
}
/// Range inside of a `Span` used for diagnostics when we only have access to relative positions.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub struct InnerSpan {
pub start: usize,
pub end: usize,
}
impl InnerSpan {
pub fn new(start: usize, end: usize) -> InnerSpan {
InnerSpan { start, end }
}
}
/// Requirements for a `StableHashingContext` to be used in this crate.
///
/// This is a hack to allow using the [`HashStable_Generic`] derive macro
/// instead of implementing everything in rustc_middle.
pub trait HashStableContext {
fn def_path_hash(&self, def_id: DefId) -> DefPathHash;
fn hash_spans(&self) -> bool;
/// Accesses `sess.opts.unstable_opts.incremental_ignore_spans` since
/// we don't have easy access to a `Session`
fn unstable_opts_incremental_ignore_spans(&self) -> bool;
fn def_span(&self, def_id: LocalDefId) -> Span;
fn span_data_to_lines_and_cols(
&mut self,
span: &SpanData,
) -> Option<(StableSourceFileId, usize, BytePos, usize, BytePos)>;
fn hashing_controls(&self) -> HashingControls;
}
impl<CTX> HashStable<CTX> for Span
where
CTX: HashStableContext,
{
/// Hashes a span in a stable way. We can't directly hash the span's `BytePos`
/// fields (that would be similar to hashing pointers, since those are just
/// offsets into the `SourceMap`). Instead, we hash the (file name, line, column)
/// triple, which stays the same even if the containing `SourceFile` has moved
/// within the `SourceMap`.
///
/// Also note that we are hashing byte offsets for the column, not unicode
/// codepoint offsets. For the purpose of the hash that's sufficient.
/// Also, hashing filenames is expensive so we avoid doing it twice when the
/// span starts and ends in the same file, which is almost always the case.
fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher) {
const TAG_VALID_SPAN: u8 = 0;
const TAG_INVALID_SPAN: u8 = 1;
const TAG_RELATIVE_SPAN: u8 = 2;
if !ctx.hash_spans() {
return;
}
let span = self.data_untracked();
span.ctxt.hash_stable(ctx, hasher);
span.parent.hash_stable(ctx, hasher);
if span.is_dummy() {
Hash::hash(&TAG_INVALID_SPAN, hasher);
return;
}
if let Some(parent) = span.parent {
let def_span = ctx.def_span(parent).data_untracked();
if def_span.contains(span) {
// This span is enclosed in a definition: only hash the relative position.
Hash::hash(&TAG_RELATIVE_SPAN, hasher);
(span.lo - def_span.lo).to_u32().hash_stable(ctx, hasher);
(span.hi - def_span.lo).to_u32().hash_stable(ctx, hasher);
return;
}
}
// If this is not an empty or invalid span, we want to hash the last
// position that belongs to it, as opposed to hashing the first
// position past it.
let Some((file, line_lo, col_lo, line_hi, col_hi)) = ctx.span_data_to_lines_and_cols(&span)
else {
Hash::hash(&TAG_INVALID_SPAN, hasher);
return;
};
Hash::hash(&TAG_VALID_SPAN, hasher);
Hash::hash(&file, hasher);
// Hash both the length and the end location (line/column) of a span. If we
// hash only the length, for example, then two otherwise equal spans with
// different end locations will have the same hash. This can cause a problem
// during incremental compilation wherein a previous result for a query that
// depends on the end location of a span will be incorrectly reused when the
// end location of the span it depends on has changed (see issue #74890). A
// similar analysis applies if some query depends specifically on the length
// of the span, but we only hash the end location. So hash both.
let col_lo_trunc = (col_lo.0 as u64) & 0xFF;
let line_lo_trunc = ((line_lo as u64) & 0xFF_FF_FF) << 8;
let col_hi_trunc = (col_hi.0 as u64) & 0xFF << 32;
let line_hi_trunc = ((line_hi as u64) & 0xFF_FF_FF) << 40;
let col_line = col_lo_trunc | line_lo_trunc | col_hi_trunc | line_hi_trunc;
let len = (span.hi - span.lo).0;
Hash::hash(&col_line, hasher);
Hash::hash(&len, hasher);
}
}
/// Useful type to use with `Result<>` indicate that an error has already
/// been reported to the user, so no need to continue checking.
///
/// The `()` field is necessary: it is non-`pub`, which means values of this
/// type cannot be constructed outside of this crate.
#[derive(Clone, Copy, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
#[derive(HashStable_Generic)]
pub struct ErrorGuaranteed(());
impl ErrorGuaranteed {
/// Don't use this outside of `DiagCtxtInner::emit_diagnostic`!
#[deprecated = "should only be used in `DiagCtxtInner::emit_diagnostic`"]
pub fn unchecked_error_guaranteed() -> Self {
ErrorGuaranteed(())
}
pub fn raise_fatal(self) -> ! {
FatalError.raise()
}
}
impl<E: rustc_serialize::Encoder> Encodable<E> for ErrorGuaranteed {
#[inline]
fn encode(&self, _e: &mut E) {
panic!(
"should never serialize an `ErrorGuaranteed`, as we do not write metadata or \
incremental caches in case errors occurred"
)
}
}
impl<D: rustc_serialize::Decoder> Decodable<D> for ErrorGuaranteed {
#[inline]
fn decode(_d: &mut D) -> ErrorGuaranteed {
panic!(
"`ErrorGuaranteed` should never have been serialized to metadata or incremental caches"
)
}
}