1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 // ignore-lexer-test FIXME #15679
13 //! The CodeMap tracks all the source code used within a single crate, mapping
14 //! from integer byte positions to the original source code location. Each bit
15 //! of source parsed during crate parsing (typically files, in-memory strings,
16 //! or various bits of macro expansion) cover a continuous range of bytes in the
17 //! CodeMap and are represented by FileMaps. Byte positions are stored in
18 //! `spans` and used pervasively in the compiler. They are absolute positions
19 //! within the CodeMap, which upon request can be converted to line and column
20 //! information, source code snippets, etc.
22 pub use self::MacroFormat::*;
24 use std::cell::RefCell;
25 use std::num::ToPrimitive;
26 use std::ops::{Add, Sub};
30 use serialize::{Encodable, Decodable, Encoder, Decoder};
33 fn from_uint(n: uint) -> Self;
34 fn to_uint(&self) -> uint;
37 /// A byte offset. Keep this small (currently 32-bits), as AST contains
39 #[derive(Clone, Copy, PartialEq, Eq, Hash, PartialOrd, Show)]
40 pub struct BytePos(pub u32);
42 /// A character offset. Because of multibyte utf8 characters, a byte offset
43 /// is not equivalent to a character offset. The CodeMap will convert BytePos
44 /// values to CharPos values as necessary.
45 #[derive(Copy, PartialEq, Hash, PartialOrd, Show)]
46 pub struct CharPos(pub uint);
48 // FIXME: Lots of boilerplate in these impls, but so far my attempts to fix
49 // have been unsuccessful
51 impl Pos for BytePos {
52 fn from_uint(n: uint) -> BytePos { BytePos(n as u32) }
53 fn to_uint(&self) -> uint { let BytePos(n) = *self; n as uint }
56 impl Add for BytePos {
57 type Output = BytePos;
59 fn add(self, rhs: BytePos) -> BytePos {
60 BytePos((self.to_uint() + rhs.to_uint()) as u32)
64 impl Sub for BytePos {
65 type Output = BytePos;
67 fn sub(self, rhs: BytePos) -> BytePos {
68 BytePos((self.to_uint() - rhs.to_uint()) as u32)
72 impl Pos for CharPos {
73 fn from_uint(n: uint) -> CharPos { CharPos(n) }
74 fn to_uint(&self) -> uint { let CharPos(n) = *self; n }
77 impl Add for CharPos {
78 type Output = CharPos;
80 fn add(self, rhs: CharPos) -> CharPos {
81 CharPos(self.to_uint() + rhs.to_uint())
85 impl Sub for CharPos {
86 type Output = CharPos;
88 fn sub(self, rhs: CharPos) -> CharPos {
89 CharPos(self.to_uint() - rhs.to_uint())
93 /// Spans represent a region of code, used for error reporting. Positions in spans
94 /// are *absolute* positions from the beginning of the codemap, not positions
95 /// relative to FileMaps. Methods on the CodeMap can be used to relate spans back
96 /// to the original source.
97 #[derive(Clone, Copy, Show, Hash)]
101 /// Information about where the macro came from, if this piece of
102 /// code was created by a macro expansion.
106 pub const DUMMY_SP: Span = Span { lo: BytePos(0), hi: BytePos(0), expn_id: NO_EXPANSION };
108 // Generic span to be used for code originating from the command line
109 pub const COMMAND_LINE_SP: Span = Span { lo: BytePos(0),
111 expn_id: COMMAND_LINE_EXPN };
113 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Show, Copy)]
114 pub struct Spanned<T> {
119 impl PartialEq for Span {
120 fn eq(&self, other: &Span) -> bool {
121 return (*self).lo == (*other).lo && (*self).hi == (*other).hi;
123 fn ne(&self, other: &Span) -> bool { !(*self).eq(other) }
128 impl Encodable for Span {
129 /* Note #1972 -- spans are encoded but not decoded */
130 fn encode<S: Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
135 impl Decodable for Span {
136 fn decode<D: Decoder>(_d: &mut D) -> Result<Span, D::Error> {
141 pub fn spanned<T>(lo: BytePos, hi: BytePos, t: T) -> Spanned<T> {
142 respan(mk_sp(lo, hi), t)
145 pub fn respan<T>(sp: Span, t: T) -> Spanned<T> {
146 Spanned {node: t, span: sp}
149 pub fn dummy_spanned<T>(t: T) -> Spanned<T> {
153 /* assuming that we're not in macro expansion */
154 pub fn mk_sp(lo: BytePos, hi: BytePos) -> Span {
155 Span {lo: lo, hi: hi, expn_id: NO_EXPANSION}
158 /// Return the span itself if it doesn't come from a macro expansion,
159 /// otherwise return the call site span up to the `enclosing_sp` by
160 /// following the `expn_info` chain.
161 pub fn original_sp(cm: &CodeMap, sp: Span, enclosing_sp: Span) -> Span {
162 let call_site1 = cm.with_expn_info(sp.expn_id, |ei| ei.map(|ei| ei.call_site));
163 let call_site2 = cm.with_expn_info(enclosing_sp.expn_id, |ei| ei.map(|ei| ei.call_site));
164 match (call_site1, call_site2) {
166 (Some(call_site1), Some(call_site2)) if call_site1 == call_site2 => sp,
167 (Some(call_site1), _) => original_sp(cm, call_site1, enclosing_sp),
171 /// A source code location used for error reporting
173 /// Information about the original source
174 pub file: Rc<FileMap>,
175 /// The (1-based) line number
177 /// The (0-based) column offset
181 /// A source code location used as the result of lookup_char_pos_adj
182 // Actually, *none* of the clients use the filename *or* file field;
183 // perhaps they should just be removed.
184 pub struct LocWithOpt {
185 pub filename: FileName,
188 pub file: Option<Rc<FileMap>>,
191 // used to be structural records. Better names, anyone?
192 pub struct FileMapAndLine { pub fm: Rc<FileMap>, pub line: uint }
193 pub struct FileMapAndBytePos { pub fm: Rc<FileMap>, pub pos: BytePos }
195 /// The syntax with which a macro was invoked.
196 #[derive(Clone, Copy, Hash, Show)]
197 pub enum MacroFormat {
198 /// e.g. #[derive(...)] <item>
204 #[derive(Clone, Hash, Show)]
205 pub struct NameAndSpan {
206 /// The name of the macro that was invoked to create the thing
209 /// The format with which the macro was invoked.
210 pub format: MacroFormat,
211 /// The span of the macro definition itself. The macro may not
212 /// have a sensible definition span (e.g. something defined
213 /// completely inside libsyntax) in which case this is None.
214 pub span: Option<Span>
217 /// Extra information for tracking macro expansion of spans
218 #[derive(Hash, Show)]
219 pub struct ExpnInfo {
220 /// The location of the actual macro invocation, e.g. `let x =
223 /// This may recursively refer to other macro invocations, e.g. if
224 /// `foo!()` invoked `bar!()` internally, and there was an
225 /// expression inside `bar!`; the call_site of the expression in
226 /// the expansion would point to the `bar!` invocation; that
227 /// call_site span would have its own ExpnInfo, with the call_site
228 /// pointing to the `foo!` invocation.
230 /// Information about the macro and its definition.
232 /// The `callee` of the inner expression in the `call_site`
233 /// example would point to the `macro_rules! bar { ... }` and that
234 /// of the `bar!()` invocation would point to the `macro_rules!
236 pub callee: NameAndSpan
239 #[derive(PartialEq, Eq, Clone, Show, Hash, RustcEncodable, RustcDecodable, Copy)]
240 pub struct ExpnId(u32);
242 pub const NO_EXPANSION: ExpnId = ExpnId(-1);
243 // For code appearing from the command line
244 pub const COMMAND_LINE_EXPN: ExpnId = ExpnId(-2);
247 pub fn from_llvm_cookie(cookie: c_uint) -> ExpnId {
248 ExpnId(cookie as u32)
251 pub fn to_llvm_cookie(self) -> i32 {
252 let ExpnId(cookie) = self;
257 pub type FileName = String;
259 pub struct FileLines {
260 pub file: Rc<FileMap>,
264 /// Identifies an offset of a multi-byte character in a FileMap
266 pub struct MultiByteChar {
267 /// The absolute offset of the character in the CodeMap
269 /// The number of bytes, >=2
273 /// A single source in the CodeMap
275 /// The name of the file that the source came from, source that doesn't
276 /// originate from files has names between angle brackets by convention,
279 /// The complete source code
281 /// The start position of this source in the CodeMap
282 pub start_pos: BytePos,
283 /// Locations of lines beginnings in the source code
284 pub lines: RefCell<Vec<BytePos> >,
285 /// Locations of multi-byte characters in the source code
286 pub multibyte_chars: RefCell<Vec<MultiByteChar> >,
290 /// EFFECT: register a start-of-line offset in the
291 /// table of line-beginnings.
292 /// UNCHECKED INVARIANT: these offsets must be added in the right
293 /// order and must be in the right places; there is shared knowledge
294 /// about what ends a line between this file and parse.rs
295 /// WARNING: pos param here is the offset relative to start of CodeMap,
296 /// and CodeMap will append a newline when adding a filemap without a newline at the end,
297 /// so the safe way to call this is with value calculated as
298 /// filemap.start_pos + newline_offset_relative_to_the_start_of_filemap.
299 pub fn next_line(&self, pos: BytePos) {
300 // the new charpos must be > the last one (or it's the first one).
301 let mut lines = self.lines.borrow_mut();
302 let line_len = lines.len();
303 assert!(line_len == 0 || ((*lines)[line_len - 1] < pos));
307 /// get a line from the list of pre-computed line-beginnings
309 pub fn get_line(&self, line_number: uint) -> Option<String> {
310 let lines = self.lines.borrow();
311 lines.get(line_number).map(|&line| {
312 let begin: BytePos = line - self.start_pos;
313 let begin = begin.to_uint();
314 let slice = &self.src[begin..];
315 match slice.find('\n') {
316 Some(e) => &slice[0..e],
322 pub fn record_multibyte_char(&self, pos: BytePos, bytes: uint) {
323 assert!(bytes >=2 && bytes <= 4);
324 let mbc = MultiByteChar {
328 self.multibyte_chars.borrow_mut().push(mbc);
331 pub fn is_real_file(&self) -> bool {
332 !(self.name.starts_with("<") &&
333 self.name.ends_with(">"))
338 pub files: RefCell<Vec<Rc<FileMap>>>,
339 expansions: RefCell<Vec<ExpnInfo>>
343 pub fn new() -> CodeMap {
345 files: RefCell::new(Vec::new()),
346 expansions: RefCell::new(Vec::new()),
350 pub fn new_filemap(&self, filename: FileName, src: String) -> Rc<FileMap> {
351 let mut files = self.files.borrow_mut();
352 let start_pos = match files.last() {
354 Some(last) => last.start_pos.to_uint() + last.src.len(),
357 // Remove utf-8 BOM if any.
358 // FIXME #12884: no efficient/safe way to remove from the start of a string
359 // and reuse the allocation.
360 let mut src = if src.starts_with("\u{feff}") {
361 String::from_str(&src[3..])
363 String::from_str(&src[])
366 // Append '\n' in case it's not already there.
367 // This is a workaround to prevent CodeMap.lookup_filemap_idx from accidentally
368 // overflowing into the next filemap in case the last byte of span is also the last
369 // byte of filemap, which leads to incorrect results from CodeMap.span_to_*.
370 if src.len() > 0 && !src.ends_with("\n") {
374 let filemap = Rc::new(FileMap {
376 src: src.to_string(),
377 start_pos: Pos::from_uint(start_pos),
378 lines: RefCell::new(Vec::new()),
379 multibyte_chars: RefCell::new(Vec::new()),
382 files.push(filemap.clone());
387 pub fn mk_substr_filename(&self, sp: Span) -> String {
388 let pos = self.lookup_char_pos(sp.lo);
389 (format!("<{}:{}:{}>",
392 pos.col.to_uint() + 1)).to_string()
395 /// Lookup source information about a BytePos
396 pub fn lookup_char_pos(&self, pos: BytePos) -> Loc {
400 pub fn lookup_char_pos_adj(&self, pos: BytePos) -> LocWithOpt {
401 let loc = self.lookup_char_pos(pos);
403 filename: loc.file.name.to_string(),
410 pub fn span_to_string(&self, sp: Span) -> String {
411 if self.files.borrow().len() == 0 && sp == DUMMY_SP {
412 return "no-location".to_string();
415 let lo = self.lookup_char_pos_adj(sp.lo);
416 let hi = self.lookup_char_pos_adj(sp.hi);
417 return (format!("{}:{}:{}: {}:{}",
420 lo.col.to_uint() + 1,
422 hi.col.to_uint() + 1)).to_string()
425 pub fn span_to_filename(&self, sp: Span) -> FileName {
426 self.lookup_char_pos(sp.lo).file.name.to_string()
429 pub fn span_to_lines(&self, sp: Span) -> FileLines {
430 let lo = self.lookup_char_pos(sp.lo);
431 let hi = self.lookup_char_pos(sp.hi);
432 let mut lines = Vec::new();
433 for i in range(lo.line - 1u, hi.line as uint) {
436 FileLines {file: lo.file, lines: lines}
439 pub fn span_to_snippet(&self, sp: Span) -> Option<String> {
440 let begin = self.lookup_byte_offset(sp.lo);
441 let end = self.lookup_byte_offset(sp.hi);
443 // FIXME #8256: this used to be an assert but whatever precondition
444 // it's testing isn't true for all spans in the AST, so to allow the
445 // caller to not have to panic (and it can't catch it since the CodeMap
446 // isn't sendable), return None
447 if begin.fm.start_pos != end.fm.start_pos {
450 Some((&begin.fm.src[begin.pos.to_uint()..end.pos.to_uint()]).to_string())
454 pub fn get_filemap(&self, filename: &str) -> Rc<FileMap> {
455 for fm in self.files.borrow().iter() {
456 if filename == fm.name {
460 panic!("asking for {} which we don't know about", filename);
463 pub fn lookup_byte_offset(&self, bpos: BytePos) -> FileMapAndBytePos {
464 let idx = self.lookup_filemap_idx(bpos);
465 let fm = (*self.files.borrow())[idx].clone();
466 let offset = bpos - fm.start_pos;
467 FileMapAndBytePos {fm: fm, pos: offset}
470 /// Converts an absolute BytePos to a CharPos relative to the filemap and above.
471 pub fn bytepos_to_file_charpos(&self, bpos: BytePos) -> CharPos {
472 let idx = self.lookup_filemap_idx(bpos);
473 let files = self.files.borrow();
474 let map = &(*files)[idx];
476 // The number of extra bytes due to multibyte chars in the FileMap
477 let mut total_extra_bytes = 0;
479 for mbc in map.multibyte_chars.borrow().iter() {
480 debug!("{}-byte char at {:?}", mbc.bytes, mbc.pos);
482 // every character is at least one byte, so we only
483 // count the actual extra bytes.
484 total_extra_bytes += mbc.bytes - 1;
485 // We should never see a byte position in the middle of a
487 assert!(bpos.to_uint() >= mbc.pos.to_uint() + mbc.bytes);
493 assert!(map.start_pos.to_uint() + total_extra_bytes <= bpos.to_uint());
494 CharPos(bpos.to_uint() - map.start_pos.to_uint() - total_extra_bytes)
497 fn lookup_filemap_idx(&self, pos: BytePos) -> uint {
498 let files = self.files.borrow();
500 let len = files.len();
504 let m = (a + b) / 2u;
505 if files[m].start_pos > pos {
511 // There can be filemaps with length 0. These have the same start_pos as
512 // the previous filemap, but are not the filemaps we want (because they
513 // are length 0, they cannot contain what we are looking for). So,
514 // rewind until we find a useful filemap.
516 let lines = files[a].lines.borrow();
522 panic!("position {} does not resolve to a source location",
528 panic!("position {} does not resolve to a source location",
535 fn lookup_line(&self, pos: BytePos) -> FileMapAndLine {
536 let idx = self.lookup_filemap_idx(pos);
538 let files = self.files.borrow();
539 let f = (*files)[idx].clone();
542 let lines = f.lines.borrow();
543 let mut b = lines.len();
545 let m = (a + b) / 2u;
546 if (*lines)[m] > pos { b = m; } else { a = m; }
549 FileMapAndLine {fm: f, line: a}
552 fn lookup_pos(&self, pos: BytePos) -> Loc {
553 let FileMapAndLine {fm: f, line: a} = self.lookup_line(pos);
554 let line = a + 1u; // Line numbers start at 1
555 let chpos = self.bytepos_to_file_charpos(pos);
556 let linebpos = (*f.lines.borrow())[a];
557 let linechpos = self.bytepos_to_file_charpos(linebpos);
558 debug!("byte pos {:?} is on the line at byte pos {:?}",
560 debug!("char pos {:?} is on the line at char pos {:?}",
562 debug!("byte is on line: {}", line);
563 assert!(chpos >= linechpos);
567 col: chpos - linechpos
571 pub fn record_expansion(&self, expn_info: ExpnInfo) -> ExpnId {
572 let mut expansions = self.expansions.borrow_mut();
573 expansions.push(expn_info);
574 ExpnId(expansions.len().to_u32().expect("too many ExpnInfo's!") - 1)
577 pub fn with_expn_info<T, F>(&self, id: ExpnId, f: F) -> T where
578 F: FnOnce(Option<&ExpnInfo>) -> T,
581 NO_EXPANSION => f(None),
582 ExpnId(i) => f(Some(&(*self.expansions.borrow())[i as uint]))
586 /// Check if a span is "internal" to a macro. This means that it is entirely generated by a
587 /// macro expansion and contains no code that was passed in as an argument.
588 pub fn span_is_internal(&self, span: Span) -> bool {
589 // first, check if the given expression was generated by a macro or not
590 // we need to go back the expn_info tree to check only the arguments
591 // of the initial macro call, not the nested ones.
592 let mut is_internal = false;
593 let mut expnid = span.expn_id;
594 while self.with_expn_info(expnid, |expninfo| {
597 // save the parent expn_id for next loop iteration
598 expnid = info.call_site.expn_id;
599 if info.callee.name == "format_args" {
600 // This is a hack because the format_args builtin calls unstable APIs.
601 // I spent like 6 hours trying to solve this more generally but am stupid.
604 } else if info.callee.span.is_none() {
605 // it's a compiler built-in, we *really* don't want to mess with it
606 // so we skip it, unless it was called by a regular macro, in which case
607 // we will handle the caller macro next turn
609 true // continue looping
611 // was this expression from the current macro arguments ?
612 is_internal = !( span.lo > info.call_site.lo &&
613 span.hi < info.call_site.hi );
614 true // continue looping
617 _ => false // stop looping
619 }) { /* empty while loop body */ }
630 let cm = CodeMap::new();
631 let fm = cm.new_filemap("blork.rs".to_string(),
632 "first line.\nsecond line".to_string());
633 fm.next_line(BytePos(0));
634 assert_eq!(fm.get_line(0), Some("first line.".to_string()));
635 // TESTING BROKEN BEHAVIOR:
636 fm.next_line(BytePos(10));
637 assert_eq!(fm.get_line(1), Some(".".to_string()));
643 let cm = CodeMap::new();
644 let fm = cm.new_filemap("blork.rs".to_string(),
645 "first line.\nsecond line".to_string());
646 // TESTING *REALLY* BROKEN BEHAVIOR:
647 fm.next_line(BytePos(0));
648 fm.next_line(BytePos(10));
649 fm.next_line(BytePos(2));
652 fn init_code_map() -> CodeMap {
653 let cm = CodeMap::new();
654 let fm1 = cm.new_filemap("blork.rs".to_string(),
655 "first line.\nsecond line".to_string());
656 let fm2 = cm.new_filemap("empty.rs".to_string(),
658 let fm3 = cm.new_filemap("blork2.rs".to_string(),
659 "first line.\nsecond line".to_string());
661 fm1.next_line(BytePos(0));
662 fm1.next_line(BytePos(12));
663 fm2.next_line(BytePos(24));
664 fm3.next_line(BytePos(24));
665 fm3.next_line(BytePos(34));
672 // Test lookup_byte_offset
673 let cm = init_code_map();
675 let fmabp1 = cm.lookup_byte_offset(BytePos(22));
676 assert_eq!(fmabp1.fm.name, "blork.rs");
677 assert_eq!(fmabp1.pos, BytePos(22));
679 let fmabp2 = cm.lookup_byte_offset(BytePos(24));
680 assert_eq!(fmabp2.fm.name, "blork2.rs");
681 assert_eq!(fmabp2.pos, BytePos(0));
686 // Test bytepos_to_file_charpos
687 let cm = init_code_map();
689 let cp1 = cm.bytepos_to_file_charpos(BytePos(22));
690 assert_eq!(cp1, CharPos(22));
692 let cp2 = cm.bytepos_to_file_charpos(BytePos(24));
693 assert_eq!(cp2, CharPos(0));
698 // Test zero-length filemaps.
699 let cm = init_code_map();
701 let loc1 = cm.lookup_char_pos(BytePos(22));
702 assert_eq!(loc1.file.name, "blork.rs");
703 assert_eq!(loc1.line, 2);
704 assert_eq!(loc1.col, CharPos(10));
706 let loc2 = cm.lookup_char_pos(BytePos(24));
707 assert_eq!(loc2.file.name, "blork2.rs");
708 assert_eq!(loc2.line, 1);
709 assert_eq!(loc2.col, CharPos(0));
712 fn init_code_map_mbc() -> CodeMap {
713 let cm = CodeMap::new();
714 // € is a three byte utf8 char.
716 cm.new_filemap("blork.rs".to_string(),
717 "fir€st €€€€ line.\nsecond line".to_string());
718 let fm2 = cm.new_filemap("blork2.rs".to_string(),
719 "first line€€.\n€ second line".to_string());
721 fm1.next_line(BytePos(0));
722 fm1.next_line(BytePos(22));
723 fm2.next_line(BytePos(40));
724 fm2.next_line(BytePos(58));
726 fm1.record_multibyte_char(BytePos(3), 3);
727 fm1.record_multibyte_char(BytePos(9), 3);
728 fm1.record_multibyte_char(BytePos(12), 3);
729 fm1.record_multibyte_char(BytePos(15), 3);
730 fm1.record_multibyte_char(BytePos(18), 3);
731 fm2.record_multibyte_char(BytePos(50), 3);
732 fm2.record_multibyte_char(BytePos(53), 3);
733 fm2.record_multibyte_char(BytePos(58), 3);
740 // Test bytepos_to_file_charpos in the presence of multi-byte chars
741 let cm = init_code_map_mbc();
743 let cp1 = cm.bytepos_to_file_charpos(BytePos(3));
744 assert_eq!(cp1, CharPos(3));
746 let cp2 = cm.bytepos_to_file_charpos(BytePos(6));
747 assert_eq!(cp2, CharPos(4));
749 let cp3 = cm.bytepos_to_file_charpos(BytePos(56));
750 assert_eq!(cp3, CharPos(12));
752 let cp4 = cm.bytepos_to_file_charpos(BytePos(61));
753 assert_eq!(cp4, CharPos(15));
758 // Test span_to_lines for a span ending at the end of filemap
759 let cm = init_code_map();
760 let span = Span {lo: BytePos(12), hi: BytePos(23), expn_id: NO_EXPANSION};
761 let file_lines = cm.span_to_lines(span);
763 assert_eq!(file_lines.file.name, "blork.rs");
764 assert_eq!(file_lines.lines.len(), 1);
765 assert_eq!(file_lines.lines[0], 1u);
770 // Test span_to_snippet for a span ending at the end of filemap
771 let cm = init_code_map();
772 let span = Span {lo: BytePos(12), hi: BytePos(23), expn_id: NO_EXPANSION};
773 let snippet = cm.span_to_snippet(span);
775 assert_eq!(snippet, Some("second line".to_string()));
780 // Test span_to_str for a span ending at the end of filemap
781 let cm = init_code_map();
782 let span = Span {lo: BytePos(12), hi: BytePos(23), expn_id: NO_EXPANSION};
783 let sstr = cm.span_to_string(span);
785 assert_eq!(sstr, "blork.rs:2:1: 2:12");