diff options
Diffstat (limited to 'src/librustdoc/html/macro_expansion.rs')
| -rw-r--r-- | src/librustdoc/html/macro_expansion.rs | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/src/librustdoc/html/macro_expansion.rs b/src/librustdoc/html/macro_expansion.rs new file mode 100644 index 00000000000..9098e92a5cd --- /dev/null +++ b/src/librustdoc/html/macro_expansion.rs @@ -0,0 +1,156 @@ +use rustc_ast::visit::{Visitor, walk_crate, walk_expr, walk_item, walk_pat, walk_stmt}; +use rustc_ast::{Crate, Expr, Item, Pat, Stmt}; +use rustc_data_structures::fx::FxHashMap; +use rustc_span::source_map::SourceMap; +use rustc_span::{BytePos, Span}; + +use crate::config::{OutputFormat, RenderOptions}; + +/// It returns the expanded macros correspondence map. +pub(crate) fn source_macro_expansion( + krate: &Crate, + render_options: &RenderOptions, + output_format: OutputFormat, + source_map: &SourceMap, +) -> FxHashMap<BytePos, Vec<ExpandedCode>> { + if output_format == OutputFormat::Html + && !render_options.html_no_source + && render_options.generate_macro_expansion + { + let mut expanded_visitor = ExpandedCodeVisitor { expanded_codes: Vec::new(), source_map }; + walk_crate(&mut expanded_visitor, krate); + expanded_visitor.compute_expanded() + } else { + Default::default() + } +} + +/// Contains information about macro expansion in the source code pages. +#[derive(Debug)] +pub(crate) struct ExpandedCode { + /// The line where the macro expansion starts. + pub(crate) start_line: u32, + /// The line where the macro expansion ends. + pub(crate) end_line: u32, + /// The source code of the expanded macro. + pub(crate) code: String, + /// The span of macro callsite. + pub(crate) span: Span, +} + +/// Contains temporary information of macro expanded code. +/// +/// As we go through the HIR visitor, if any span overlaps with another, they will +/// both be merged. +struct ExpandedCodeInfo { + /// Callsite of the macro. + span: Span, + /// Expanded macro source code (HTML escaped). + code: String, + /// Span of macro-generated code. + expanded_span: Span, +} + +/// HIR visitor which retrieves expanded macro. +/// +/// Once done, the `expanded_codes` will be transformed into a vec of [`ExpandedCode`] +/// which contains the information needed when running the source code highlighter. +pub(crate) struct ExpandedCodeVisitor<'ast> { + expanded_codes: Vec<ExpandedCodeInfo>, + source_map: &'ast SourceMap, +} + +impl<'ast> ExpandedCodeVisitor<'ast> { + fn handle_new_span<F: Fn() -> String>(&mut self, new_span: Span, f: F) { + if new_span.is_dummy() || !new_span.from_expansion() { + return; + } + let callsite_span = new_span.source_callsite(); + if let Some(index) = + self.expanded_codes.iter().position(|info| info.span.overlaps(callsite_span)) + { + let info = &mut self.expanded_codes[index]; + if new_span.contains(info.expanded_span) { + // New macro expansion recursively contains the old one, so replace it. + info.span = callsite_span; + info.expanded_span = new_span; + info.code = f(); + } else { + // We push the new item after the existing one. + let expanded_code = &mut self.expanded_codes[index]; + expanded_code.code.push('\n'); + expanded_code.code.push_str(&f()); + let lo = BytePos(expanded_code.expanded_span.lo().0.min(new_span.lo().0)); + let hi = BytePos(expanded_code.expanded_span.hi().0.min(new_span.hi().0)); + expanded_code.expanded_span = expanded_code.expanded_span.with_lo(lo).with_hi(hi); + } + } else { + // We add a new item. + self.expanded_codes.push(ExpandedCodeInfo { + span: callsite_span, + code: f(), + expanded_span: new_span, + }); + } + } + + fn compute_expanded(mut self) -> FxHashMap<BytePos, Vec<ExpandedCode>> { + self.expanded_codes.sort_unstable_by(|item1, item2| item1.span.cmp(&item2.span)); + let mut expanded: FxHashMap<BytePos, Vec<ExpandedCode>> = FxHashMap::default(); + for ExpandedCodeInfo { span, code, .. } in self.expanded_codes { + if let Ok(lines) = self.source_map.span_to_lines(span) + && !lines.lines.is_empty() + { + let mut out = String::new(); + super::highlight::write_code(&mut out, &code, None, None, None); + let first = lines.lines.first().unwrap(); + let end = lines.lines.last().unwrap(); + expanded.entry(lines.file.start_pos).or_default().push(ExpandedCode { + start_line: first.line_index as u32 + 1, + end_line: end.line_index as u32 + 1, + code: out, + span, + }); + } + } + expanded + } +} + +// We need to use the AST pretty printing because: +// +// 1. HIR pretty printing doesn't display accurately the code (like `impl Trait`). +// 2. `SourceMap::snippet_opt` might fail if the source is not available. +impl<'ast> Visitor<'ast> for ExpandedCodeVisitor<'ast> { + fn visit_expr(&mut self, expr: &'ast Expr) { + if expr.span.from_expansion() { + self.handle_new_span(expr.span, || rustc_ast_pretty::pprust::expr_to_string(expr)); + } else { + walk_expr(self, expr); + } + } + + fn visit_item(&mut self, item: &'ast Item) { + if item.span.from_expansion() { + self.handle_new_span(item.span, || rustc_ast_pretty::pprust::item_to_string(item)); + } else { + walk_item(self, item); + } + } + + fn visit_stmt(&mut self, stmt: &'ast Stmt) { + if stmt.span.from_expansion() { + self.handle_new_span(stmt.span, || rustc_ast_pretty::pprust::stmt_to_string(stmt)); + } else { + walk_stmt(self, stmt); + } + } + + fn visit_pat(&mut self, pat: &'ast Pat) { + if pat.span.from_expansion() { + self.handle_new_span(pat.span, || rustc_ast_pretty::pprust::pat_to_string(pat)); + } else { + walk_pat(self, pat); + } + } +} |