src/libsyntax/diagnostics/plugin.rs

   1 // Copyright 2014 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.
   4 //
   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.
  10
  11 use std::collections::BTreeMap;
  12 use std::env;
  13
  14 use ast;
  15 use ast::{Ident, Name};
  16 use source_map;
  17 use syntax_pos::Span;
  18 use ext::base::{ExtCtxt, MacEager, MacResult};
  19 use ext::build::AstBuilder;
  20 use parse::token;
  21 use ptr::P;
  22 use symbol::{keywords, Symbol};
  23 use tokenstream::{TokenTree};
  24
  25 use diagnostics::metadata::output_metadata;
  26
  27 pub use errors::*;
  28
  29 // Maximum width of any line in an extended error description (inclusive).
  30 const MAX_DESCRIPTION_WIDTH: usize = 80;
  31
  32 /// Error information type.
  33 pub struct ErrorInfo {
  34     pub description: Option<Name>,
  35     pub use_site: Option<Span>
  36 }
  37
  38 /// Mapping from error codes to metadata.
  39 pub type ErrorMap = BTreeMap<Name, ErrorInfo>;
  40
  41 pub fn expand_diagnostic_used<'cx>(ecx: &'cx mut ExtCtxt,
  42                                    span: Span,
  43                                    token_tree: &[TokenTree])
  44                                    -> Box<dyn MacResult+'cx> {
  45     let code = match (token_tree.len(), token_tree.get(0)) {
  46         (1, Some(&TokenTree::Token(_, token::Ident(code, _)))) => code,
  47         _ => unreachable!()
  48     };
  49
  50     ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
  51         match diagnostics.get_mut(&code.name) {
  52             // Previously used errors.
  53             Some(&mut ErrorInfo { description: _, use_site: Some(previous_span) }) => {
  54                 ecx.struct_span_warn(span, &format!(
  55                     "diagnostic code {} already used", code
  56                 )).span_note(previous_span, "previous invocation")
  57                   .emit();
  58             }
  59             // Newly used errors.
  60             Some(ref mut info) => {
  61                 info.use_site = Some(span);
  62             }
  63             // Unregistered errors.
  64             None => {
  65                 ecx.span_err(span, &format!(
  66                     "used diagnostic code {} not registered", code
  67                 ));
  68             }
  69         }
  70     });
  71     MacEager::expr(ecx.expr_tuple(span, Vec::new()))
  72 }
  73
  74 pub fn expand_register_diagnostic<'cx>(ecx: &'cx mut ExtCtxt,
  75                                        span: Span,
  76                                        token_tree: &[TokenTree])
  77                                        -> Box<dyn MacResult+'cx> {
  78     let (code, description) = match (
  79         token_tree.len(),
  80         token_tree.get(0),
  81         token_tree.get(1),
  82         token_tree.get(2)
  83     ) {
  84         (1, Some(&TokenTree::Token(_, token::Ident(ref code, _))), None, None) => {
  85             (code, None)
  86         },
  87         (3, Some(&TokenTree::Token(_, token::Ident(ref code, _))),
  88             Some(&TokenTree::Token(_, token::Comma)),
  89             Some(&TokenTree::Token(_, token::Literal(token::StrRaw(description, _), None)))) => {
  90             (code, Some(description))
  91         }
  92         _ => unreachable!()
  93     };
  94
  95     // Check that the description starts and ends with a newline and doesn't
  96     // overflow the maximum line width.
  97     description.map(|raw_msg| {
  98         let msg = raw_msg.as_str();
  99         if !msg.starts_with("\n") || !msg.ends_with("\n") {
 100             ecx.span_err(span, &format!(
 101                 "description for error code {} doesn't start and end with a newline",
 102                 code
 103             ));
 104         }
 105
 106         // URLs can be unavoidably longer than the line limit, so we allow them.
 107         // Allowed format is: `[name]: https://www.rust-lang.org/`
 108         let is_url = |l: &str| l.starts_with("[") && l.contains("]:") && l.contains("http");
 109
 110         if msg.lines().any(|line| line.len() > MAX_DESCRIPTION_WIDTH && !is_url(line)) {
 111             ecx.span_err(span, &format!(
 112                 "description for error code {} contains a line longer than {} characters.\n\
 113                  if you're inserting a long URL use the footnote style to bypass this check.",
 114                 code, MAX_DESCRIPTION_WIDTH
 115             ));
 116         }
 117     });
 118     // Add the error to the map.
 119     ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
 120         let info = ErrorInfo {
 121             description,
 122             use_site: None
 123         };
 124         if diagnostics.insert(code.name, info).is_some() {
 125             ecx.span_err(span, &format!(
 126                 "diagnostic code {} already registered", code
 127             ));
 128         }
 129     });
 130     let sym = Ident::with_empty_ctxt(Symbol::gensym(&format!(
 131         "__register_diagnostic_{}", code
 132     )));
 133     MacEager::items(smallvec![
 134         ecx.item_mod(
 135             span,
 136             span,
 137             sym,
 138             Vec::new(),
 139             Vec::new()
 140         )
 141     ])
 142 }
 143
 144 pub fn expand_build_diagnostic_array<'cx>(ecx: &'cx mut ExtCtxt,
 145                                           span: Span,
 146                                           token_tree: &[TokenTree])
 147                                           -> Box<dyn MacResult+'cx> {
 148     assert_eq!(token_tree.len(), 3);
 149     let (crate_name, name) = match (&token_tree[0], &token_tree[2]) {
 150         (
 151             // Crate name.
 152             &TokenTree::Token(_, token::Ident(ref crate_name, _)),
 153             // DIAGNOSTICS ident.
 154             &TokenTree::Token(_, token::Ident(ref name, _))
 155         ) => (*&crate_name, name),
 156         _ => unreachable!()
 157     };
 158
 159     // Output error metadata to `tmp/extended-errors/<target arch>/<crate name>.json`
 160     if let Ok(target_triple) = env::var("CFG_COMPILER_HOST_TRIPLE") {
 161         ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
 162             if let Err(e) = output_metadata(ecx,
 163                                             &target_triple,
 164                                             &crate_name.as_str(),
 165                                             diagnostics) {
 166                 ecx.span_bug(span, &format!(
 167                     "error writing metadata for triple `{}` and crate `{}`, error: {}, \
 168                      cause: {:?}",
 169                     target_triple, crate_name, e.description(), e.cause()
 170                 ));
 171             }
 172         });
 173     } else {
 174         ecx.span_err(span, &format!(
 175             "failed to write metadata for crate `{}` because $CFG_COMPILER_HOST_TRIPLE is not set",
 176             crate_name));
 177     }
 178
 179     // Construct the output expression.
 180     let (count, expr) =
 181         ecx.parse_sess.registered_diagnostics.with_lock(|diagnostics| {
 182             let descriptions: Vec<P<ast::Expr>> =
 183                 diagnostics.iter().filter_map(|(&code, info)| {
 184                     info.description.map(|description| {
 185                         ecx.expr_tuple(span, vec![
 186                             ecx.expr_str(span, code),
 187                             ecx.expr_str(span, description)
 188                         ])
 189                     })
 190                 }).collect();
 191             (descriptions.len(), ecx.expr_vec(span, descriptions))
 192         });
 193
 194     let static_ = ecx.lifetime(span, keywords::StaticLifetime.ident());
 195     let ty_str = ecx.ty_rptr(
 196         span,
 197         ecx.ty_ident(span, ecx.ident_of("str")),
 198         Some(static_),
 199         ast::Mutability::Immutable,
 200     );
 201
 202     let ty = ecx.ty(
 203         span,
 204         ast::TyKind::Array(
 205             ecx.ty(
 206                 span,
 207                 ast::TyKind::Tup(vec![ty_str.clone(), ty_str])
 208             ),
 209             ast::AnonConst {
 210                 id: ast::DUMMY_NODE_ID,
 211                 value: ecx.expr_usize(span, count),
 212             },
 213         ),
 214     );
 215
 216     MacEager::items(smallvec![
 217         P(ast::Item {
 218             ident: *name,
 219             attrs: Vec::new(),
 220             id: ast::DUMMY_NODE_ID,
 221             node: ast::ItemKind::Const(
 222                 ty,
 223                 expr,
 224             ),
 225             vis: source_map::respan(span.shrink_to_lo(), ast::VisibilityKind::Public),
 226             span,
 227             tokens: None,
 228         })
 229     ])
 230 }