compiler/rustc_mir/src/util/spanview.rs

   1 use rustc_hir::def_id::DefId;
   2 use rustc_middle::hir;
   3 use rustc_middle::mir::*;
   4 use rustc_middle::ty::TyCtxt;
   5 use rustc_session::config::MirSpanview;
   6 use rustc_span::{BytePos, Pos, Span, SyntaxContext};
   7
   8 use std::cmp;
   9 use std::io::{self, Write};
  10
  11 pub const TOOLTIP_INDENT: &str = "    ";
  12
  13 const CARET: char = '\u{2038}'; // Unicode `CARET`
  14 const ANNOTATION_LEFT_BRACKET: char = '\u{298a}'; // Unicode `Z NOTATION RIGHT BINDING BRACKET
  15 const ANNOTATION_RIGHT_BRACKET: char = '\u{2989}'; // Unicode `Z NOTATION LEFT BINDING BRACKET`
  16 const NEW_LINE_SPAN: &str = "</span>\n<span class=\"line\">";
  17 const HEADER: &str = r#"<!DOCTYPE html>
  18 <html>
  19 <head>"#;
  20 const START_BODY: &str = r#"</head>
  21 <body>"#;
  22 const FOOTER: &str = r#"</body>
  23 </html>"#;
  24
  25 const STYLE_SECTION: &str = r#"<style>
  26     .line {
  27         counter-increment: line;
  28     }
  29     .line:before {
  30         content: counter(line) ": ";
  31         font-family: Menlo, Monaco, monospace;
  32         font-style: italic;
  33         width: 3.8em;
  34         display: inline-block;
  35         text-align: right;
  36         filter: opacity(50%);
  37         -webkit-user-select: none;
  38     }
  39     .code {
  40         color: #dddddd;
  41         background-color: #222222;
  42         font-family: Menlo, Monaco, monospace;
  43         line-height: 1.4em;
  44         border-bottom: 2px solid #222222;
  45         white-space: pre;
  46         display: inline-block;
  47     }
  48     .odd {
  49         background-color: #55bbff;
  50         color: #223311;
  51     }
  52     .even {
  53         background-color: #ee7756;
  54         color: #551133;
  55     }
  56     .code {
  57         --index: calc(var(--layer) - 1);
  58         padding-top: calc(var(--index) * 0.15em);
  59         filter:
  60             hue-rotate(calc(var(--index) * 25deg))
  61             saturate(calc(100% - (var(--index) * 2%)))
  62             brightness(calc(100% - (var(--index) * 1.5%)));
  63     }
  64     .annotation {
  65         color: #4444ff;
  66         font-family: monospace;
  67         font-style: italic;
  68         display: none;
  69         -webkit-user-select: none;
  70     }
  71     body:active .annotation {
  72         /* requires holding mouse down anywhere on the page */
  73         display: inline-block;
  74     }
  75     span:hover .annotation {
  76         /* requires hover over a span ONLY on its first line */
  77         display: inline-block;
  78     }
  79 </style>"#;
  80
  81 /// Metadata to highlight the span of a MIR BasicBlock, Statement, or Terminator.
  82 #[derive(Clone, Debug)]
  83 pub struct SpanViewable {
  84     pub bb: BasicBlock,
  85     pub span: Span,
  86     pub id: String,
  87     pub tooltip: String,
  88 }
  89
  90 /// Write a spanview HTML+CSS file to analyze MIR element spans.
  91 pub fn write_mir_fn_spanview<'tcx, W>(
  92     tcx: TyCtxt<'tcx>,
  93     body: &Body<'tcx>,
  94     spanview: MirSpanview,
  95     title: &str,
  96     w: &mut W,
  97 ) -> io::Result<()>
  98 where
  99     W: Write,
 100 {
 101     let def_id = body.source.def_id();
 102     let hir_body = hir_body(tcx, def_id);
 103     if hir_body.is_none() {
 104         return Ok(());
 105     }
 106     let body_span = hir_body.unwrap().value.span;
 107     let mut span_viewables = Vec::new();
 108     for (bb, data) in body.basic_blocks().iter_enumerated() {
 109         match spanview {
 110             MirSpanview::Statement => {
 111                 for (i, statement) in data.statements.iter().enumerate() {
 112                     if let Some(span_viewable) =
 113                         statement_span_viewable(tcx, body_span, bb, i, statement)
 114                     {
 115                         span_viewables.push(span_viewable);
 116                     }
 117                 }
 118                 if let Some(span_viewable) = terminator_span_viewable(tcx, body_span, bb, data) {
 119                     span_viewables.push(span_viewable);
 120                 }
 121             }
 122             MirSpanview::Terminator => {
 123                 if let Some(span_viewable) = terminator_span_viewable(tcx, body_span, bb, data) {
 124                     span_viewables.push(span_viewable);
 125                 }
 126             }
 127             MirSpanview::Block => {
 128                 if let Some(span_viewable) = block_span_viewable(tcx, body_span, bb, data) {
 129                     span_viewables.push(span_viewable);
 130                 }
 131             }
 132         }
 133     }
 134     write_document(tcx, fn_span(tcx, def_id), span_viewables, title, w)?;
 135     Ok(())
 136 }
 137
 138 /// Generate a spanview HTML+CSS document for the given local function `def_id`, and a pre-generated
 139 /// list `SpanViewable`s.
 140 pub fn write_document<'tcx, W>(
 141     tcx: TyCtxt<'tcx>,
 142     spanview_span: Span,
 143     mut span_viewables: Vec<SpanViewable>,
 144     title: &str,
 145     w: &mut W,
 146 ) -> io::Result<()>
 147 where
 148     W: Write,
 149 {
 150     let mut from_pos = spanview_span.lo();
 151     let end_pos = spanview_span.hi();
 152     let source_map = tcx.sess.source_map();
 153     let start = source_map.lookup_char_pos(from_pos);
 154     let indent_to_initial_start_col = " ".repeat(start.col.to_usize());
 155     debug!(
 156         "spanview_span={:?}; source is:\n{}{}",
 157         spanview_span,
 158         indent_to_initial_start_col,
 159         source_map.span_to_snippet(spanview_span).expect("function should have printable source")
 160     );
 161     writeln!(w, "{}", HEADER)?;
 162     writeln!(w, "<title>{}</title>", title)?;
 163     writeln!(w, "{}", STYLE_SECTION)?;
 164     writeln!(w, "{}", START_BODY)?;
 165     write!(
 166         w,
 167         r#"<div class="code" style="counter-reset: line {}"><span class="line">{}"#,
 168         start.line - 1,
 169         indent_to_initial_start_col,
 170     )?;
 171     span_viewables.sort_unstable_by(|a, b| {
 172         let a = a.span;
 173         let b = b.span;
 174         if a.lo() == b.lo() {
 175             // Sort hi() in reverse order so shorter spans are attempted after longer spans.
 176             // This should give shorter spans a higher "layer", so they are not covered by
 177             // the longer spans.
 178             b.hi().partial_cmp(&a.hi())
 179         } else {
 180             a.lo().partial_cmp(&b.lo())
 181         }
 182         .unwrap()
 183     });
 184     let mut ordered_viewables = &span_viewables[..];
 185     const LOWEST_VIEWABLE_LAYER: usize = 1;
 186     let mut alt = false;
 187     while ordered_viewables.len() > 0 {
 188         debug!(
 189             "calling write_next_viewable with from_pos={}, end_pos={}, and viewables len={}",
 190             from_pos.to_usize(),
 191             end_pos.to_usize(),
 192             ordered_viewables.len()
 193         );
 194         let curr_id = &ordered_viewables[0].id;
 195         let (next_from_pos, next_ordered_viewables) = write_next_viewable_with_overlaps(
 196             tcx,
 197             from_pos,
 198             end_pos,
 199             ordered_viewables,
 200             alt,
 201             LOWEST_VIEWABLE_LAYER,
 202             w,
 203         )?;
 204         debug!(
 205             "DONE calling write_next_viewable, with new from_pos={}, \
 206              and remaining viewables len={}",
 207             next_from_pos.to_usize(),
 208             next_ordered_viewables.len()
 209         );
 210         assert!(
 211             from_pos != next_from_pos || ordered_viewables.len() != next_ordered_viewables.len(),
 212             "write_next_viewable_with_overlaps() must make a state change"
 213         );
 214         from_pos = next_from_pos;
 215         if next_ordered_viewables.len() != ordered_viewables.len() {
 216             ordered_viewables = next_ordered_viewables;
 217             if let Some(next_ordered_viewable) = ordered_viewables.first() {
 218                 if &next_ordered_viewable.id != curr_id {
 219                     alt = !alt;
 220                 }
 221             }
 222         }
 223     }
 224     if from_pos < end_pos {
 225         write_coverage_gap(tcx, from_pos, end_pos, w)?;
 226     }
 227     writeln!(w, r#"</span></div>"#)?;
 228     writeln!(w, "{}", FOOTER)?;
 229     Ok(())
 230 }
 231
 232 /// Format a string showing the start line and column, and end line and column within a file.
 233 pub fn source_range_no_file<'tcx>(tcx: TyCtxt<'tcx>, span: &Span) -> String {
 234     let source_map = tcx.sess.source_map();
 235     let start = source_map.lookup_char_pos(span.lo());
 236     let end = source_map.lookup_char_pos(span.hi());
 237     format!("{}:{}-{}:{}", start.line, start.col.to_usize() + 1, end.line, end.col.to_usize() + 1)
 238 }
 239
 240 pub fn statement_kind_name(statement: &Statement<'_>) -> &'static str {
 241     use StatementKind::*;
 242     match statement.kind {
 243         Assign(..) => "Assign",
 244         FakeRead(..) => "FakeRead",
 245         SetDiscriminant { .. } => "SetDiscriminant",
 246         StorageLive(..) => "StorageLive",
 247         StorageDead(..) => "StorageDead",
 248         LlvmInlineAsm(..) => "LlvmInlineAsm",
 249         Retag(..) => "Retag",
 250         AscribeUserType(..) => "AscribeUserType",
 251         Coverage(..) => "Coverage",
 252         CopyNonOverlapping(..) => "CopyNonOverlapping",
 253         Nop => "Nop",
 254     }
 255 }
 256
 257 pub fn terminator_kind_name(term: &Terminator<'_>) -> &'static str {
 258     use TerminatorKind::*;
 259     match term.kind {
 260         Goto { .. } => "Goto",
 261         SwitchInt { .. } => "SwitchInt",
 262         Resume => "Resume",
 263         Abort => "Abort",
 264         Return => "Return",
 265         Unreachable => "Unreachable",
 266         Drop { .. } => "Drop",
 267         DropAndReplace { .. } => "DropAndReplace",
 268         Call { .. } => "Call",
 269         Assert { .. } => "Assert",
 270         Yield { .. } => "Yield",
 271         GeneratorDrop => "GeneratorDrop",
 272         FalseEdge { .. } => "FalseEdge",
 273         FalseUnwind { .. } => "FalseUnwind",
 274         InlineAsm { .. } => "InlineAsm",
 275     }
 276 }
 277
 278 fn statement_span_viewable<'tcx>(
 279     tcx: TyCtxt<'tcx>,
 280     body_span: Span,
 281     bb: BasicBlock,
 282     i: usize,
 283     statement: &Statement<'tcx>,
 284 ) -> Option<SpanViewable> {
 285     let span = statement.source_info.span;
 286     if !body_span.contains(span) {
 287         return None;
 288     }
 289     let id = format!("{}[{}]", bb.index(), i);
 290     let tooltip = tooltip(tcx, &id, span, vec![statement.clone()], &None);
 291     Some(SpanViewable { bb, span, id, tooltip })
 292 }
 293
 294 fn terminator_span_viewable<'tcx>(
 295     tcx: TyCtxt<'tcx>,
 296     body_span: Span,
 297     bb: BasicBlock,
 298     data: &BasicBlockData<'tcx>,
 299 ) -> Option<SpanViewable> {
 300     let term = data.terminator();
 301     let span = term.source_info.span;
 302     if !body_span.contains(span) {
 303         return None;
 304     }
 305     let id = format!("{}:{}", bb.index(), terminator_kind_name(term));
 306     let tooltip = tooltip(tcx, &id, span, vec![], &data.terminator);
 307     Some(SpanViewable { bb, span, id, tooltip })
 308 }
 309
 310 fn block_span_viewable<'tcx>(
 311     tcx: TyCtxt<'tcx>,
 312     body_span: Span,
 313     bb: BasicBlock,
 314     data: &BasicBlockData<'tcx>,
 315 ) -> Option<SpanViewable> {
 316     let span = compute_block_span(data, body_span);
 317     if !body_span.contains(span) {
 318         return None;
 319     }
 320     let id = format!("{}", bb.index());
 321     let tooltip = tooltip(tcx, &id, span, data.statements.clone(), &data.terminator);
 322     Some(SpanViewable { bb, span, id, tooltip })
 323 }
 324
 325 fn compute_block_span<'tcx>(data: &BasicBlockData<'tcx>, body_span: Span) -> Span {
 326     let mut span = data.terminator().source_info.span;
 327     for statement_span in data.statements.iter().map(|statement| statement.source_info.span) {
 328         // Only combine Spans from the root context, and within the function's body_span.
 329         if statement_span.ctxt() == SyntaxContext::root() && body_span.contains(statement_span) {
 330             span = span.to(statement_span);
 331         }
 332     }
 333     span
 334 }
 335
 336 /// Recursively process each ordered span. Spans that overlap will have progressively varying
 337 /// styles, such as increased padding for each overlap. Non-overlapping adjacent spans will
 338 /// have alternating style choices, to help distinguish between them if, visually adjacent.
 339 /// The `layer` is incremented for each overlap, and the `alt` bool alternates between true
 340 /// and false, for each adjacent non-overlapping span. Source code between the spans (code
 341 /// that is not in any coverage region) has neutral styling.
 342 fn write_next_viewable_with_overlaps<'tcx, 'b, W>(
 343     tcx: TyCtxt<'tcx>,
 344     mut from_pos: BytePos,
 345     mut to_pos: BytePos,
 346     ordered_viewables: &'b [SpanViewable],
 347     alt: bool,
 348     layer: usize,
 349     w: &mut W,
 350 ) -> io::Result<(BytePos, &'b [SpanViewable])>
 351 where
 352     W: Write,
 353 {
 354     let debug_indent = "  ".repeat(layer);
 355     let (viewable, mut remaining_viewables) =
 356         ordered_viewables.split_first().expect("ordered_viewables should have some");
 357
 358     if from_pos < viewable.span.lo() {
 359         debug!(
 360             "{}advance from_pos to next SpanViewable (from from_pos={} to viewable.span.lo()={} \
 361              of {:?}), with to_pos={}",
 362             debug_indent,
 363             from_pos.to_usize(),
 364             viewable.span.lo().to_usize(),
 365             viewable.span,
 366             to_pos.to_usize()
 367         );
 368         let hi = cmp::min(viewable.span.lo(), to_pos);
 369         write_coverage_gap(tcx, from_pos, hi, w)?;
 370         from_pos = hi;
 371         if from_pos < viewable.span.lo() {
 372             debug!(
 373                 "{}EARLY RETURN: stopped before getting to next SpanViewable, at {}",
 374                 debug_indent,
 375                 from_pos.to_usize()
 376             );
 377             return Ok((from_pos, ordered_viewables));
 378         }
 379     }
 380
 381     if from_pos < viewable.span.hi() {
 382         // Set to_pos to the end of this `viewable` to ensure the recursive calls stop writing
 383         // with room to print the tail.
 384         to_pos = cmp::min(viewable.span.hi(), to_pos);
 385         debug!(
 386             "{}update to_pos (if not closer) to viewable.span.hi()={}; to_pos is now {}",
 387             debug_indent,
 388             viewable.span.hi().to_usize(),
 389             to_pos.to_usize()
 390         );
 391     }
 392
 393     let mut subalt = false;
 394     while remaining_viewables.len() > 0 && remaining_viewables[0].span.overlaps(viewable.span) {
 395         let overlapping_viewable = &remaining_viewables[0];
 396         debug!("{}overlapping_viewable.span={:?}", debug_indent, overlapping_viewable.span);
 397
 398         let span =
 399             trim_span(viewable.span, from_pos, cmp::min(overlapping_viewable.span.lo(), to_pos));
 400         let mut some_html_snippet = if from_pos <= viewable.span.hi() || viewable.span.is_empty() {
 401             // `viewable` is not yet fully rendered, so start writing the span, up to either the
 402             // `to_pos` or the next `overlapping_viewable`, whichever comes first.
 403             debug!(
 404                 "{}make html_snippet (may not write it if early exit) for partial span {:?} \
 405                  of viewable.span {:?}",
 406                 debug_indent, span, viewable.span
 407             );
 408             from_pos = span.hi();
 409             make_html_snippet(tcx, span, Some(&viewable))
 410         } else {
 411             None
 412         };
 413
 414         // Defer writing the HTML snippet (until after early return checks) ONLY for empty spans.
 415         // An empty Span with Some(html_snippet) is probably a tail marker. If there is an early
 416         // exit, there should be another opportunity to write the tail marker.
 417         if !span.is_empty() {
 418             if let Some(ref html_snippet) = some_html_snippet {
 419                 debug!(
 420                     "{}write html_snippet for that partial span of viewable.span {:?}",
 421                     debug_indent, viewable.span
 422                 );
 423                 write_span(html_snippet, &viewable.tooltip, alt, layer, w)?;
 424             }
 425             some_html_snippet = None;
 426         }
 427
 428         if from_pos < overlapping_viewable.span.lo() {
 429             debug!(
 430                 "{}EARLY RETURN: from_pos={} has not yet reached the \
 431                  overlapping_viewable.span {:?}",
 432                 debug_indent,
 433                 from_pos.to_usize(),
 434                 overlapping_viewable.span
 435             );
 436             // must have reached `to_pos` before reaching the start of the
 437             // `overlapping_viewable.span`
 438             return Ok((from_pos, ordered_viewables));
 439         }
 440
 441         if from_pos == to_pos
 442             && !(from_pos == overlapping_viewable.span.lo() && overlapping_viewable.span.is_empty())
 443         {
 444             debug!(
 445                 "{}EARLY RETURN: from_pos=to_pos={} and overlapping_viewable.span {:?} is not \
 446                  empty, or not from_pos",
 447                 debug_indent,
 448                 to_pos.to_usize(),
 449                 overlapping_viewable.span
 450             );
 451             // `to_pos` must have occurred before the overlapping viewable. Return
 452             // `ordered_viewables` so we can continue rendering the `viewable`, from after the
 453             // `to_pos`.
 454             return Ok((from_pos, ordered_viewables));
 455         }
 456
 457         if let Some(ref html_snippet) = some_html_snippet {
 458             debug!(
 459                 "{}write html_snippet for that partial span of viewable.span {:?}",
 460                 debug_indent, viewable.span
 461             );
 462             write_span(html_snippet, &viewable.tooltip, alt, layer, w)?;
 463         }
 464
 465         debug!(
 466             "{}recursively calling write_next_viewable with from_pos={}, to_pos={}, \
 467              and viewables len={}",
 468             debug_indent,
 469             from_pos.to_usize(),
 470             to_pos.to_usize(),
 471             remaining_viewables.len()
 472         );
 473         // Write the overlaps (and the overlaps' overlaps, if any) up to `to_pos`.
 474         let curr_id = &remaining_viewables[0].id;
 475         let (next_from_pos, next_remaining_viewables) = write_next_viewable_with_overlaps(
 476             tcx,
 477             from_pos,
 478             to_pos,
 479             &remaining_viewables,
 480             subalt,
 481             layer + 1,
 482             w,
 483         )?;
 484         debug!(
 485             "{}DONE recursively calling write_next_viewable, with new from_pos={}, and remaining \
 486              viewables len={}",
 487             debug_indent,
 488             next_from_pos.to_usize(),
 489             next_remaining_viewables.len()
 490         );
 491         assert!(
 492             from_pos != next_from_pos
 493                 || remaining_viewables.len() != next_remaining_viewables.len(),
 494             "write_next_viewable_with_overlaps() must make a state change"
 495         );
 496         from_pos = next_from_pos;
 497         if next_remaining_viewables.len() != remaining_viewables.len() {
 498             remaining_viewables = next_remaining_viewables;
 499             if let Some(next_ordered_viewable) = remaining_viewables.first() {
 500                 if &next_ordered_viewable.id != curr_id {
 501                     subalt = !subalt;
 502                 }
 503             }
 504         }
 505     }
 506     if from_pos <= viewable.span.hi() {
 507         let span = trim_span(viewable.span, from_pos, to_pos);
 508         debug!(
 509             "{}After overlaps, writing (end span?) {:?} of viewable.span {:?}",
 510             debug_indent, span, viewable.span
 511         );
 512         if let Some(ref html_snippet) = make_html_snippet(tcx, span, Some(&viewable)) {
 513             from_pos = span.hi();
 514             write_span(html_snippet, &viewable.tooltip, alt, layer, w)?;
 515         }
 516     }
 517     debug!("{}RETURN: No more overlap", debug_indent);
 518     Ok((
 519         from_pos,
 520         if from_pos < viewable.span.hi() { ordered_viewables } else { remaining_viewables },
 521     ))
 522 }
 523
 524 #[inline(always)]
 525 fn write_coverage_gap<'tcx, W>(
 526     tcx: TyCtxt<'tcx>,
 527     lo: BytePos,
 528     hi: BytePos,
 529     w: &mut W,
 530 ) -> io::Result<()>
 531 where
 532     W: Write,
 533 {
 534     let span = Span::with_root_ctxt(lo, hi);
 535     if let Some(ref html_snippet) = make_html_snippet(tcx, span, None) {
 536         write_span(html_snippet, "", false, 0, w)
 537     } else {
 538         Ok(())
 539     }
 540 }
 541
 542 fn write_span<W>(
 543     html_snippet: &str,
 544     tooltip: &str,
 545     alt: bool,
 546     layer: usize,
 547     w: &mut W,
 548 ) -> io::Result<()>
 549 where
 550     W: Write,
 551 {
 552     let maybe_alt_class = if layer > 0 {
 553         if alt { " odd" } else { " even" }
 554     } else {
 555         ""
 556     };
 557     let maybe_title_attr = if !tooltip.is_empty() {
 558         format!(" title=\"{}\"", escape_attr(tooltip))
 559     } else {
 560         "".to_owned()
 561     };
 562     if layer == 1 {
 563         write!(w, "<span>")?;
 564     }
 565     for (i, line) in html_snippet.lines().enumerate() {
 566         if i > 0 {
 567             write!(w, "{}", NEW_LINE_SPAN)?;
 568         }
 569         write!(
 570             w,
 571             r#"<span class="code{}" style="--layer: {}"{}>{}</span>"#,
 572             maybe_alt_class, layer, maybe_title_attr, line
 573         )?;
 574     }
 575     // Check for and translate trailing newlines, because `str::lines()` ignores them
 576     if html_snippet.ends_with('\n') {
 577         write!(w, "{}", NEW_LINE_SPAN)?;
 578     }
 579     if layer == 1 {
 580         write!(w, "</span>")?;
 581     }
 582     Ok(())
 583 }
 584
 585 fn make_html_snippet<'tcx>(
 586     tcx: TyCtxt<'tcx>,
 587     span: Span,
 588     some_viewable: Option<&SpanViewable>,
 589 ) -> Option<String> {
 590     let source_map = tcx.sess.source_map();
 591     let snippet = source_map
 592         .span_to_snippet(span)
 593         .unwrap_or_else(|err| bug!("span_to_snippet error for span {:?}: {:?}", span, err));
 594     let html_snippet = if let Some(viewable) = some_viewable {
 595         let is_head = span.lo() == viewable.span.lo();
 596         let is_tail = span.hi() == viewable.span.hi();
 597         let mut labeled_snippet = if is_head {
 598             format!(r#"<span class="annotation">{}{}</span>"#, viewable.id, ANNOTATION_LEFT_BRACKET)
 599         } else {
 600             "".to_owned()
 601         };
 602         if span.is_empty() {
 603             if is_head && is_tail {
 604                 labeled_snippet.push(CARET);
 605             }
 606         } else {
 607             labeled_snippet.push_str(&escape_html(&snippet));
 608         };
 609         if is_tail {
 610             labeled_snippet.push_str(&format!(
 611                 r#"<span class="annotation">{}{}</span>"#,
 612                 ANNOTATION_RIGHT_BRACKET, viewable.id
 613             ));
 614         }
 615         labeled_snippet
 616     } else {
 617         escape_html(&snippet)
 618     };
 619     if html_snippet.is_empty() { None } else { Some(html_snippet) }
 620 }
 621
 622 fn tooltip<'tcx>(
 623     tcx: TyCtxt<'tcx>,
 624     spanview_id: &str,
 625     span: Span,
 626     statements: Vec<Statement<'tcx>>,
 627     terminator: &Option<Terminator<'tcx>>,
 628 ) -> String {
 629     let source_map = tcx.sess.source_map();
 630     let mut text = Vec::new();
 631     text.push(format!("{}: {}:", spanview_id, &source_map.span_to_embeddable_string(span)));
 632     for statement in statements {
 633         let source_range = source_range_no_file(tcx, &statement.source_info.span);
 634         text.push(format!(
 635             "\n{}{}: {}: {}",
 636             TOOLTIP_INDENT,
 637             source_range,
 638             statement_kind_name(&statement),
 639             format!("{:?}", statement)
 640         ));
 641     }
 642     if let Some(term) = terminator {
 643         let source_range = source_range_no_file(tcx, &term.source_info.span);
 644         text.push(format!(
 645             "\n{}{}: {}: {:?}",
 646             TOOLTIP_INDENT,
 647             source_range,
 648             terminator_kind_name(term),
 649             term.kind
 650         ));
 651     }
 652     text.join("")
 653 }
 654
 655 fn trim_span(span: Span, from_pos: BytePos, to_pos: BytePos) -> Span {
 656     trim_span_hi(trim_span_lo(span, from_pos), to_pos)
 657 }
 658
 659 fn trim_span_lo(span: Span, from_pos: BytePos) -> Span {
 660     if from_pos <= span.lo() { span } else { span.with_lo(cmp::min(span.hi(), from_pos)) }
 661 }
 662
 663 fn trim_span_hi(span: Span, to_pos: BytePos) -> Span {
 664     if to_pos >= span.hi() { span } else { span.with_hi(cmp::max(span.lo(), to_pos)) }
 665 }
 666
 667 fn fn_span<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Span {
 668     let hir_id =
 669         tcx.hir().local_def_id_to_hir_id(def_id.as_local().expect("expected DefId is local"));
 670     let fn_decl_span = tcx.hir().span(hir_id);
 671     if let Some(body_span) = hir_body(tcx, def_id).map(|hir_body| hir_body.value.span) {
 672         if fn_decl_span.ctxt() == body_span.ctxt() { fn_decl_span.to(body_span) } else { body_span }
 673     } else {
 674         fn_decl_span
 675     }
 676 }
 677
 678 fn hir_body<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<&'tcx rustc_hir::Body<'tcx>> {
 679     let hir_node = tcx.hir().get_if_local(def_id).expect("expected DefId is local");
 680     hir::map::associated_body(hir_node).map(|fn_body_id| tcx.hir().body(fn_body_id))
 681 }
 682
 683 fn escape_html(s: &str) -> String {
 684     s.replace("&", "&amp;").replace("<", "&lt;").replace(">", "&gt;")
 685 }
 686
 687 fn escape_attr(s: &str) -> String {
 688     s.replace("&", "&amp;")
 689         .replace("\"", "&quot;")
 690         .replace("'", "&#39;")
 691         .replace("<", "&lt;")
 692         .replace(">", "&gt;")
 693 }