diff options
Diffstat (limited to 'compiler/rustc_middle/src/mir/spanview.rs')
| -rw-r--r-- | compiler/rustc_middle/src/mir/spanview.rs | 691 |
1 files changed, 691 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/mir/spanview.rs b/compiler/rustc_middle/src/mir/spanview.rs new file mode 100644 index 000000000..4418b848e --- /dev/null +++ b/compiler/rustc_middle/src/mir/spanview.rs @@ -0,0 +1,691 @@ +use rustc_hir::def_id::DefId; +use rustc_middle::hir; +use rustc_middle::mir::*; +use rustc_middle::ty::TyCtxt; +use rustc_session::config::MirSpanview; +use rustc_span::{BytePos, Pos, Span, SyntaxContext}; + +use std::cmp; +use std::io::{self, Write}; + +pub const TOOLTIP_INDENT: &str = " "; + +const CARET: char = '\u{2038}'; // Unicode `CARET` +const ANNOTATION_LEFT_BRACKET: char = '\u{298a}'; // Unicode `Z NOTATION RIGHT BINDING BRACKET +const ANNOTATION_RIGHT_BRACKET: char = '\u{2989}'; // Unicode `Z NOTATION LEFT BINDING BRACKET` +const NEW_LINE_SPAN: &str = "</span>\n<span class=\"line\">"; +const HEADER: &str = r#"<!DOCTYPE html> +<html> +<head>"#; +const START_BODY: &str = r#"</head> +<body>"#; +const FOOTER: &str = r#"</body> +</html>"#; + +const STYLE_SECTION: &str = r#"<style> + .line { + counter-increment: line; + } + .line:before { + content: counter(line) ": "; + font-family: Menlo, Monaco, monospace; + font-style: italic; + width: 3.8em; + display: inline-block; + text-align: right; + filter: opacity(50%); + -webkit-user-select: none; + } + .code { + color: #dddddd; + background-color: #222222; + font-family: Menlo, Monaco, monospace; + line-height: 1.4em; + border-bottom: 2px solid #222222; + white-space: pre; + display: inline-block; + } + .odd { + background-color: #55bbff; + color: #223311; + } + .even { + background-color: #ee7756; + color: #551133; + } + .code { + --index: calc(var(--layer) - 1); + padding-top: calc(var(--index) * 0.15em); + filter: + hue-rotate(calc(var(--index) * 25deg)) + saturate(calc(100% - (var(--index) * 2%))) + brightness(calc(100% - (var(--index) * 1.5%))); + } + .annotation { + color: #4444ff; + font-family: monospace; + font-style: italic; + display: none; + -webkit-user-select: none; + } + body:active .annotation { + /* requires holding mouse down anywhere on the page */ + display: inline-block; + } + span:hover .annotation { + /* requires hover over a span ONLY on its first line */ + display: inline-block; + } +</style>"#; + +/// Metadata to highlight the span of a MIR BasicBlock, Statement, or Terminator. +#[derive(Clone, Debug)] +pub struct SpanViewable { + pub bb: BasicBlock, + pub span: Span, + pub id: String, + pub tooltip: String, +} + +/// Write a spanview HTML+CSS file to analyze MIR element spans. +pub fn write_mir_fn_spanview<'tcx, W>( + tcx: TyCtxt<'tcx>, + body: &Body<'tcx>, + spanview: MirSpanview, + title: &str, + w: &mut W, +) -> io::Result<()> +where + W: Write, +{ + let def_id = body.source.def_id(); + let hir_body = hir_body(tcx, def_id); + if hir_body.is_none() { + return Ok(()); + } + let body_span = hir_body.unwrap().value.span; + let mut span_viewables = Vec::new(); + for (bb, data) in body.basic_blocks().iter_enumerated() { + match spanview { + MirSpanview::Statement => { + for (i, statement) in data.statements.iter().enumerate() { + if let Some(span_viewable) = + statement_span_viewable(tcx, body_span, bb, i, statement) + { + span_viewables.push(span_viewable); + } + } + if let Some(span_viewable) = terminator_span_viewable(tcx, body_span, bb, data) { + span_viewables.push(span_viewable); + } + } + MirSpanview::Terminator => { + if let Some(span_viewable) = terminator_span_viewable(tcx, body_span, bb, data) { + span_viewables.push(span_viewable); + } + } + MirSpanview::Block => { + if let Some(span_viewable) = block_span_viewable(tcx, body_span, bb, data) { + span_viewables.push(span_viewable); + } + } + } + } + write_document(tcx, fn_span(tcx, def_id), span_viewables, title, w)?; + Ok(()) +} + +/// Generate a spanview HTML+CSS document for the given local function `def_id`, and a pre-generated +/// list `SpanViewable`s. +pub fn write_document<'tcx, W>( + tcx: TyCtxt<'tcx>, + spanview_span: Span, + mut span_viewables: Vec<SpanViewable>, + title: &str, + w: &mut W, +) -> io::Result<()> +where + W: Write, +{ + let mut from_pos = spanview_span.lo(); + let end_pos = spanview_span.hi(); + let source_map = tcx.sess.source_map(); + let start = source_map.lookup_char_pos(from_pos); + let indent_to_initial_start_col = " ".repeat(start.col.to_usize()); + debug!( + "spanview_span={:?}; source is:\n{}{}", + spanview_span, + indent_to_initial_start_col, + source_map.span_to_snippet(spanview_span).expect("function should have printable source") + ); + writeln!(w, "{}", HEADER)?; + writeln!(w, "<title>{}</title>", title)?; + writeln!(w, "{}", STYLE_SECTION)?; + writeln!(w, "{}", START_BODY)?; + write!( + w, + r#"<div class="code" style="counter-reset: line {}"><span class="line">{}"#, + start.line - 1, + indent_to_initial_start_col, + )?; + span_viewables.sort_unstable_by(|a, b| { + let a = a.span; + let b = b.span; + if a.lo() == b.lo() { + // Sort hi() in reverse order so shorter spans are attempted after longer spans. + // This should give shorter spans a higher "layer", so they are not covered by + // the longer spans. + b.hi().partial_cmp(&a.hi()) + } else { + a.lo().partial_cmp(&b.lo()) + } + .unwrap() + }); + let mut ordered_viewables = &span_viewables[..]; + const LOWEST_VIEWABLE_LAYER: usize = 1; + let mut alt = false; + while ordered_viewables.len() > 0 { + debug!( + "calling write_next_viewable with from_pos={}, end_pos={}, and viewables len={}", + from_pos.to_usize(), + end_pos.to_usize(), + ordered_viewables.len() + ); + let curr_id = &ordered_viewables[0].id; + let (next_from_pos, next_ordered_viewables) = write_next_viewable_with_overlaps( + tcx, + from_pos, + end_pos, + ordered_viewables, + alt, + LOWEST_VIEWABLE_LAYER, + w, + )?; + debug!( + "DONE calling write_next_viewable, with new from_pos={}, \ + and remaining viewables len={}", + next_from_pos.to_usize(), + next_ordered_viewables.len() + ); + assert!( + from_pos != next_from_pos || ordered_viewables.len() != next_ordered_viewables.len(), + "write_next_viewable_with_overlaps() must make a state change" + ); + from_pos = next_from_pos; + if next_ordered_viewables.len() != ordered_viewables.len() { + ordered_viewables = next_ordered_viewables; + if let Some(next_ordered_viewable) = ordered_viewables.first() { + if &next_ordered_viewable.id != curr_id { + alt = !alt; + } + } + } + } + if from_pos < end_pos { + write_coverage_gap(tcx, from_pos, end_pos, w)?; + } + writeln!(w, r#"</span></div>"#)?; + writeln!(w, "{}", FOOTER)?; + Ok(()) +} + +/// Format a string showing the start line and column, and end line and column within a file. +pub fn source_range_no_file<'tcx>(tcx: TyCtxt<'tcx>, span: Span) -> String { + let source_map = tcx.sess.source_map(); + let start = source_map.lookup_char_pos(span.lo()); + let end = source_map.lookup_char_pos(span.hi()); + format!("{}:{}-{}:{}", start.line, start.col.to_usize() + 1, end.line, end.col.to_usize() + 1) +} + +pub fn statement_kind_name(statement: &Statement<'_>) -> &'static str { + use StatementKind::*; + match statement.kind { + Assign(..) => "Assign", + FakeRead(..) => "FakeRead", + SetDiscriminant { .. } => "SetDiscriminant", + Deinit(..) => "Deinit", + StorageLive(..) => "StorageLive", + StorageDead(..) => "StorageDead", + Retag(..) => "Retag", + AscribeUserType(..) => "AscribeUserType", + Coverage(..) => "Coverage", + CopyNonOverlapping(..) => "CopyNonOverlapping", + Nop => "Nop", + } +} + +pub fn terminator_kind_name(term: &Terminator<'_>) -> &'static str { + use TerminatorKind::*; + match term.kind { + Goto { .. } => "Goto", + SwitchInt { .. } => "SwitchInt", + Resume => "Resume", + Abort => "Abort", + Return => "Return", + Unreachable => "Unreachable", + Drop { .. } => "Drop", + DropAndReplace { .. } => "DropAndReplace", + Call { .. } => "Call", + Assert { .. } => "Assert", + Yield { .. } => "Yield", + GeneratorDrop => "GeneratorDrop", + FalseEdge { .. } => "FalseEdge", + FalseUnwind { .. } => "FalseUnwind", + InlineAsm { .. } => "InlineAsm", + } +} + +fn statement_span_viewable<'tcx>( + tcx: TyCtxt<'tcx>, + body_span: Span, + bb: BasicBlock, + i: usize, + statement: &Statement<'tcx>, +) -> Option<SpanViewable> { + let span = statement.source_info.span; + if !body_span.contains(span) { + return None; + } + let id = format!("{}[{}]", bb.index(), i); + let tooltip = tooltip(tcx, &id, span, vec![statement.clone()], &None); + Some(SpanViewable { bb, span, id, tooltip }) +} + +fn terminator_span_viewable<'tcx>( + tcx: TyCtxt<'tcx>, + body_span: Span, + bb: BasicBlock, + data: &BasicBlockData<'tcx>, +) -> Option<SpanViewable> { + let term = data.terminator(); + let span = term.source_info.span; + if !body_span.contains(span) { + return None; + } + let id = format!("{}:{}", bb.index(), terminator_kind_name(term)); + let tooltip = tooltip(tcx, &id, span, vec![], &data.terminator); + Some(SpanViewable { bb, span, id, tooltip }) +} + +fn block_span_viewable<'tcx>( + tcx: TyCtxt<'tcx>, + body_span: Span, + bb: BasicBlock, + data: &BasicBlockData<'tcx>, +) -> Option<SpanViewable> { + let span = compute_block_span(data, body_span); + if !body_span.contains(span) { + return None; + } + let id = format!("{}", bb.index()); + let tooltip = tooltip(tcx, &id, span, data.statements.clone(), &data.terminator); + Some(SpanViewable { bb, span, id, tooltip }) +} + +fn compute_block_span<'tcx>(data: &BasicBlockData<'tcx>, body_span: Span) -> Span { + let mut span = data.terminator().source_info.span; + for statement_span in data.statements.iter().map(|statement| statement.source_info.span) { + // Only combine Spans from the root context, and within the function's body_span. + if statement_span.ctxt() == SyntaxContext::root() && body_span.contains(statement_span) { + span = span.to(statement_span); + } + } + span +} + +/// Recursively process each ordered span. Spans that overlap will have progressively varying +/// styles, such as increased padding for each overlap. Non-overlapping adjacent spans will +/// have alternating style choices, to help distinguish between them if, visually adjacent. +/// The `layer` is incremented for each overlap, and the `alt` bool alternates between true +/// and false, for each adjacent non-overlapping span. Source code between the spans (code +/// that is not in any coverage region) has neutral styling. +fn write_next_viewable_with_overlaps<'tcx, 'b, W>( + tcx: TyCtxt<'tcx>, + mut from_pos: BytePos, + mut to_pos: BytePos, + ordered_viewables: &'b [SpanViewable], + alt: bool, + layer: usize, + w: &mut W, +) -> io::Result<(BytePos, &'b [SpanViewable])> +where + W: Write, +{ + let debug_indent = " ".repeat(layer); + let (viewable, mut remaining_viewables) = + ordered_viewables.split_first().expect("ordered_viewables should have some"); + + if from_pos < viewable.span.lo() { + debug!( + "{}advance from_pos to next SpanViewable (from from_pos={} to viewable.span.lo()={} \ + of {:?}), with to_pos={}", + debug_indent, + from_pos.to_usize(), + viewable.span.lo().to_usize(), + viewable.span, + to_pos.to_usize() + ); + let hi = cmp::min(viewable.span.lo(), to_pos); + write_coverage_gap(tcx, from_pos, hi, w)?; + from_pos = hi; + if from_pos < viewable.span.lo() { + debug!( + "{}EARLY RETURN: stopped before getting to next SpanViewable, at {}", + debug_indent, + from_pos.to_usize() + ); + return Ok((from_pos, ordered_viewables)); + } + } + + if from_pos < viewable.span.hi() { + // Set to_pos to the end of this `viewable` to ensure the recursive calls stop writing + // with room to print the tail. + to_pos = cmp::min(viewable.span.hi(), to_pos); + debug!( + "{}update to_pos (if not closer) to viewable.span.hi()={}; to_pos is now {}", + debug_indent, + viewable.span.hi().to_usize(), + to_pos.to_usize() + ); + } + + let mut subalt = false; + while remaining_viewables.len() > 0 && remaining_viewables[0].span.overlaps(viewable.span) { + let overlapping_viewable = &remaining_viewables[0]; + debug!("{}overlapping_viewable.span={:?}", debug_indent, overlapping_viewable.span); + + let span = + trim_span(viewable.span, from_pos, cmp::min(overlapping_viewable.span.lo(), to_pos)); + let mut some_html_snippet = if from_pos <= viewable.span.hi() || viewable.span.is_empty() { + // `viewable` is not yet fully rendered, so start writing the span, up to either the + // `to_pos` or the next `overlapping_viewable`, whichever comes first. + debug!( + "{}make html_snippet (may not write it if early exit) for partial span {:?} \ + of viewable.span {:?}", + debug_indent, span, viewable.span + ); + from_pos = span.hi(); + make_html_snippet(tcx, span, Some(&viewable)) + } else { + None + }; + + // Defer writing the HTML snippet (until after early return checks) ONLY for empty spans. + // An empty Span with Some(html_snippet) is probably a tail marker. If there is an early + // exit, there should be another opportunity to write the tail marker. + if !span.is_empty() { + if let Some(ref html_snippet) = some_html_snippet { + debug!( + "{}write html_snippet for that partial span of viewable.span {:?}", + debug_indent, viewable.span + ); + write_span(html_snippet, &viewable.tooltip, alt, layer, w)?; + } + some_html_snippet = None; + } + + if from_pos < overlapping_viewable.span.lo() { + debug!( + "{}EARLY RETURN: from_pos={} has not yet reached the \ + overlapping_viewable.span {:?}", + debug_indent, + from_pos.to_usize(), + overlapping_viewable.span + ); + // must have reached `to_pos` before reaching the start of the + // `overlapping_viewable.span` + return Ok((from_pos, ordered_viewables)); + } + + if from_pos == to_pos + && !(from_pos == overlapping_viewable.span.lo() && overlapping_viewable.span.is_empty()) + { + debug!( + "{}EARLY RETURN: from_pos=to_pos={} and overlapping_viewable.span {:?} is not \ + empty, or not from_pos", + debug_indent, + to_pos.to_usize(), + overlapping_viewable.span + ); + // `to_pos` must have occurred before the overlapping viewable. Return + // `ordered_viewables` so we can continue rendering the `viewable`, from after the + // `to_pos`. + return Ok((from_pos, ordered_viewables)); + } + + if let Some(ref html_snippet) = some_html_snippet { + debug!( + "{}write html_snippet for that partial span of viewable.span {:?}", + debug_indent, viewable.span + ); + write_span(html_snippet, &viewable.tooltip, alt, layer, w)?; + } + + debug!( + "{}recursively calling write_next_viewable with from_pos={}, to_pos={}, \ + and viewables len={}", + debug_indent, + from_pos.to_usize(), + to_pos.to_usize(), + remaining_viewables.len() + ); + // Write the overlaps (and the overlaps' overlaps, if any) up to `to_pos`. + let curr_id = &remaining_viewables[0].id; + let (next_from_pos, next_remaining_viewables) = write_next_viewable_with_overlaps( + tcx, + from_pos, + to_pos, + &remaining_viewables, + subalt, + layer + 1, + w, + )?; + debug!( + "{}DONE recursively calling write_next_viewable, with new from_pos={}, and remaining \ + viewables len={}", + debug_indent, + next_from_pos.to_usize(), + next_remaining_viewables.len() + ); + assert!( + from_pos != next_from_pos + || remaining_viewables.len() != next_remaining_viewables.len(), + "write_next_viewable_with_overlaps() must make a state change" + ); + from_pos = next_from_pos; + if next_remaining_viewables.len() != remaining_viewables.len() { + remaining_viewables = next_remaining_viewables; + if let Some(next_ordered_viewable) = remaining_viewables.first() { + if &next_ordered_viewable.id != curr_id { + subalt = !subalt; + } + } + } + } + if from_pos <= viewable.span.hi() { + let span = trim_span(viewable.span, from_pos, to_pos); + debug!( + "{}After overlaps, writing (end span?) {:?} of viewable.span {:?}", + debug_indent, span, viewable.span + ); + if let Some(ref html_snippet) = make_html_snippet(tcx, span, Some(&viewable)) { + from_pos = span.hi(); + write_span(html_snippet, &viewable.tooltip, alt, layer, w)?; + } + } + debug!("{}RETURN: No more overlap", debug_indent); + Ok(( + from_pos, + if from_pos < viewable.span.hi() { ordered_viewables } else { remaining_viewables }, + )) +} + +#[inline(always)] +fn write_coverage_gap<'tcx, W>( + tcx: TyCtxt<'tcx>, + lo: BytePos, + hi: BytePos, + w: &mut W, +) -> io::Result<()> +where + W: Write, +{ + let span = Span::with_root_ctxt(lo, hi); + if let Some(ref html_snippet) = make_html_snippet(tcx, span, None) { + write_span(html_snippet, "", false, 0, w) + } else { + Ok(()) + } +} + +fn write_span<W>( + html_snippet: &str, + tooltip: &str, + alt: bool, + layer: usize, + w: &mut W, +) -> io::Result<()> +where + W: Write, +{ + let maybe_alt_class = if layer > 0 { + if alt { " odd" } else { " even" } + } else { + "" + }; + let maybe_title_attr = if !tooltip.is_empty() { + format!(" title=\"{}\"", escape_attr(tooltip)) + } else { + "".to_owned() + }; + if layer == 1 { + write!(w, "<span>")?; + } + for (i, line) in html_snippet.lines().enumerate() { + if i > 0 { + write!(w, "{}", NEW_LINE_SPAN)?; + } + write!( + w, + r#"<span class="code{}" style="--layer: {}"{}>{}</span>"#, + maybe_alt_class, layer, maybe_title_attr, line + )?; + } + // Check for and translate trailing newlines, because `str::lines()` ignores them + if html_snippet.ends_with('\n') { + write!(w, "{}", NEW_LINE_SPAN)?; + } + if layer == 1 { + write!(w, "</span>")?; + } + Ok(()) +} + +fn make_html_snippet<'tcx>( + tcx: TyCtxt<'tcx>, + span: Span, + some_viewable: Option<&SpanViewable>, +) -> Option<String> { + let source_map = tcx.sess.source_map(); + let snippet = source_map + .span_to_snippet(span) + .unwrap_or_else(|err| bug!("span_to_snippet error for span {:?}: {:?}", span, err)); + let html_snippet = if let Some(viewable) = some_viewable { + let is_head = span.lo() == viewable.span.lo(); + let is_tail = span.hi() == viewable.span.hi(); + let mut labeled_snippet = if is_head { + format!(r#"<span class="annotation">{}{}</span>"#, viewable.id, ANNOTATION_LEFT_BRACKET) + } else { + "".to_owned() + }; + if span.is_empty() { + if is_head && is_tail { + labeled_snippet.push(CARET); + } + } else { + labeled_snippet.push_str(&escape_html(&snippet)); + }; + if is_tail { + labeled_snippet.push_str(&format!( + r#"<span class="annotation">{}{}</span>"#, + ANNOTATION_RIGHT_BRACKET, viewable.id + )); + } + labeled_snippet + } else { + escape_html(&snippet) + }; + if html_snippet.is_empty() { None } else { Some(html_snippet) } +} + +fn tooltip<'tcx>( + tcx: TyCtxt<'tcx>, + spanview_id: &str, + span: Span, + statements: Vec<Statement<'tcx>>, + terminator: &Option<Terminator<'tcx>>, +) -> String { + let source_map = tcx.sess.source_map(); + let mut text = Vec::new(); + text.push(format!("{}: {}:", spanview_id, &source_map.span_to_embeddable_string(span))); + for statement in statements { + let source_range = source_range_no_file(tcx, statement.source_info.span); + text.push(format!( + "\n{}{}: {}: {:?}", + TOOLTIP_INDENT, + source_range, + statement_kind_name(&statement), + statement + )); + } + if let Some(term) = terminator { + let source_range = source_range_no_file(tcx, term.source_info.span); + text.push(format!( + "\n{}{}: {}: {:?}", + TOOLTIP_INDENT, + source_range, + terminator_kind_name(term), + term.kind + )); + } + text.join("") +} + +fn trim_span(span: Span, from_pos: BytePos, to_pos: BytePos) -> Span { + trim_span_hi(trim_span_lo(span, from_pos), to_pos) +} + +fn trim_span_lo(span: Span, from_pos: BytePos) -> Span { + if from_pos <= span.lo() { span } else { span.with_lo(cmp::min(span.hi(), from_pos)) } +} + +fn trim_span_hi(span: Span, to_pos: BytePos) -> Span { + if to_pos >= span.hi() { span } else { span.with_hi(cmp::max(span.lo(), to_pos)) } +} + +fn fn_span<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Span { + let fn_decl_span = tcx.def_span(def_id); + if let Some(body_span) = hir_body(tcx, def_id).map(|hir_body| hir_body.value.span) { + if fn_decl_span.eq_ctxt(body_span) { fn_decl_span.to(body_span) } else { body_span } + } else { + fn_decl_span + } +} + +fn hir_body<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> Option<&'tcx rustc_hir::Body<'tcx>> { + let hir_node = tcx.hir().get_if_local(def_id).expect("expected DefId is local"); + hir::map::associated_body(hir_node).map(|fn_body_id| tcx.hir().body(fn_body_id)) +} + +fn escape_html(s: &str) -> String { + s.replace('&', "&").replace('<', "<").replace('>', ">") +} + +fn escape_attr(s: &str) -> String { + s.replace('&', "&") + .replace('\"', """) + .replace('\'', "'") + .replace('<', "<") + .replace('>', ">") +} |