src/librustc_trans/save/mod.rs

   1 // Copyright 2012-2015 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 middle::ty;
  12 use middle::def;
  13
  14 use std::env;
  15 use std::fs::{self, File};
  16 use std::path::{Path, PathBuf};
  17
  18 use syntax::{attr};
  19 use syntax::ast::{self, NodeId, DefId};
  20 use syntax::ast_util;
  21 use syntax::codemap::*;
  22 use syntax::parse::token::{self, get_ident, keywords};
  23 use syntax::visit::{self, Visitor};
  24 use syntax::print::pprust::ty_to_string;
  25
  26 use self::span_utils::SpanUtils;
  27
  28
  29 mod span_utils;
  30 mod recorder;
  31
  32 mod dump_csv;
  33
  34 pub struct SaveContext<'l, 'tcx: 'l> {
  35     tcx: &'l ty::ctxt<'tcx>,
  36     span_utils: SpanUtils<'l>,
  37 }
  38
  39 pub struct CrateData {
  40     pub name: String,
  41     pub number: u32,
  42 }
  43
  44 /// Data for any entity in the Rust language. The actual data contained varied
  45 /// with the kind of entity being queried. See the nested structs for details.
  46 #[derive(Debug)]
  47 pub enum Data {
  48     /// Data for all kinds of functions and methods.
  49     FunctionData(FunctionData),
  50     /// Data for local and global variables (consts and statics), and fields.
  51     VariableData(VariableData),
  52     /// Data for modules.
  53     ModData(ModData),
  54     /// Data for Enums.
  55     EnumData(EnumData),
  56     /// Data for impls.
  57     ImplData(ImplData),
  58
  59     /// Data for the use of some variable (e.g., the use of a local variable, which
  60     /// will refere to that variables declaration).
  61     VariableRefData(VariableRefData),
  62     /// Data for a reference to a type or trait.
  63     TypeRefData(TypeRefData),
  64     /// Data about a function call.
  65     FunctionCallData(FunctionCallData),
  66     /// Data about a method call.
  67     MethodCallData(MethodCallData),
  68 }
  69
  70 /// Data for all kinds of functions and methods.
  71 #[derive(Debug)]
  72 pub struct FunctionData {
  73     pub id: NodeId,
  74     pub name: String,
  75     pub qualname: String,
  76     pub declaration: Option<DefId>,
  77     pub span: Span,
  78     pub scope: NodeId,
  79 }
  80
  81 /// Data for local and global variables (consts and statics).
  82 #[derive(Debug)]
  83 pub struct VariableData {
  84     pub id: NodeId,
  85     pub name: String,
  86     pub qualname: String,
  87     pub span: Span,
  88     pub scope: NodeId,
  89     pub value: String,
  90     pub type_value: String,
  91 }
  92
  93 /// Data for modules.
  94 #[derive(Debug)]
  95 pub struct ModData {
  96     pub id: NodeId,
  97     pub name: String,
  98     pub qualname: String,
  99     pub span: Span,
 100     pub scope: NodeId,
 101     pub filename: String,
 102 }
 103
 104 /// Data for enum declarations.
 105 #[derive(Debug)]
 106 pub struct EnumData {
 107     pub id: NodeId,
 108     pub value: String,
 109     pub qualname: String,
 110     pub span: Span,
 111     pub scope: NodeId,
 112 }
 113
 114 #[derive(Debug)]
 115 pub struct ImplData {
 116     pub id: NodeId,
 117     pub span: Span,
 118     pub scope: NodeId,
 119     // FIXME: I'm not really sure inline data is the best way to do this. Seems
 120     // OK in this case, but generalising leads to returning chunks of AST, which
 121     // feels wrong.
 122     pub trait_ref: Option<TypeRefData>,
 123     pub self_ref: Option<TypeRefData>,
 124 }
 125
 126 /// Data for the use of some item (e.g., the use of a local variable, which
 127 /// will refer to that variables declaration (by ref_id)).
 128 #[derive(Debug)]
 129 pub struct VariableRefData {
 130     pub name: String,
 131     pub span: Span,
 132     pub scope: NodeId,
 133     pub ref_id: DefId,
 134 }
 135
 136 /// Data for a reference to a type or trait.
 137 #[derive(Debug)]
 138 pub struct TypeRefData {
 139     pub span: Span,
 140     pub scope: NodeId,
 141     pub ref_id: DefId,
 142 }
 143
 144 /// Data about a function call.
 145 #[derive(Debug)]
 146 pub struct FunctionCallData {
 147     pub span: Span,
 148     pub scope: NodeId,
 149     pub ref_id: DefId,
 150 }
 151
 152 /// Data about a method call.
 153 #[derive(Debug)]
 154 pub struct MethodCallData {
 155     pub span: Span,
 156     pub scope: NodeId,
 157     pub ref_id: Option<DefId>,
 158     pub decl_id: Option<DefId>,
 159 }
 160
 161
 162
 163 impl<'l, 'tcx: 'l> SaveContext<'l, 'tcx> {
 164     pub fn new(tcx: &'l ty::ctxt<'tcx>,
 165                span_utils: SpanUtils<'l>)
 166                -> SaveContext<'l, 'tcx> {
 167         SaveContext {
 168             tcx: tcx,
 169             span_utils: span_utils,
 170         }
 171     }
 172
 173     // List external crates used by the current crate.
 174     pub fn get_external_crates(&self) -> Vec<CrateData> {
 175         let mut result = Vec::new();
 176
 177         self.tcx.sess.cstore.iter_crate_data(|n, cmd| {
 178             result.push(CrateData { name: cmd.name.clone(), number: n });
 179         });
 180
 181         result
 182     }
 183
 184     pub fn get_item_data(&self, item: &ast::Item) -> Data {
 185         match item.node {
 186             ast::ItemFn(..) => {
 187                 let name = self.tcx.map.path_to_string(item.id);
 188                 let qualname = format!("::{}", name);
 189                 let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Fn);
 190
 191                 Data::FunctionData(FunctionData {
 192                     id: item.id,
 193                     name: name,
 194                     qualname: qualname,
 195                     declaration: None,
 196                     span: sub_span.unwrap(),
 197                     scope: self.tcx.map.get_enclosing_scope(item.id).unwrap_or(0),
 198                 })
 199             }
 200             ast::ItemStatic(ref typ, mt, ref expr) => {
 201                 let qualname = format!("::{}", self.tcx.map.path_to_string(item.id));
 202
 203                 // If the variable is immutable, save the initialising expression.
 204                 let (value, keyword) = match mt {
 205                     ast::MutMutable => (String::from("<mutable>"), keywords::Mut),
 206                     ast::MutImmutable => (self.span_utils.snippet(expr.span), keywords::Static),
 207                 };
 208
 209                 let sub_span = self.span_utils.sub_span_after_keyword(item.span, keyword);
 210
 211                 Data::VariableData(VariableData {
 212                     id: item.id,
 213                     name: get_ident(item.ident).to_string(),
 214                     qualname: qualname,
 215                     span: sub_span.unwrap(),
 216                     scope: self.tcx.map.get_enclosing_scope(item.id).unwrap_or(0),
 217                     value: value,
 218                     type_value: ty_to_string(&typ),
 219                 })
 220             }
 221             ast::ItemConst(ref typ, ref expr) => {
 222                 let qualname = format!("::{}", self.tcx.map.path_to_string(item.id));
 223                 let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Const);
 224
 225                 Data::VariableData(VariableData {
 226                     id: item.id,
 227                     name: get_ident(item.ident).to_string(),
 228                     qualname: qualname,
 229                     span: sub_span.unwrap(),
 230                     scope: self.tcx.map.get_enclosing_scope(item.id).unwrap_or(0),
 231                     value: self.span_utils.snippet(expr.span),
 232                     type_value: ty_to_string(&typ),
 233                 })
 234             }
 235             ast::ItemMod(ref m) => {
 236                 let qualname = format!("::{}", self.tcx.map.path_to_string(item.id));
 237
 238                 let cm = self.tcx.sess.codemap();
 239                 let filename = cm.span_to_filename(m.inner);
 240
 241                 let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Mod);
 242
 243                 Data::ModData(ModData {
 244                     id: item.id,
 245                     name: get_ident(item.ident).to_string(),
 246                     qualname: qualname,
 247                     span: sub_span.unwrap(),
 248                     scope: self.tcx.map.get_enclosing_scope(item.id).unwrap_or(0),
 249                     filename: filename,
 250                 })
 251             },
 252             ast::ItemEnum(..) => {
 253                 let enum_name = format!("::{}", self.tcx.map.path_to_string(item.id));
 254                 let val = self.span_utils.snippet(item.span);
 255                 let sub_span = self.span_utils.sub_span_after_keyword(item.span, keywords::Enum);
 256
 257                 Data::EnumData(EnumData {
 258                     id: item.id,
 259                     value: val,
 260                     span: sub_span.unwrap(),
 261                     qualname: enum_name,
 262                     scope: self.tcx.map.get_enclosing_scope(item.id).unwrap_or(0),
 263                 })
 264             },
 265             ast::ItemImpl(_, _, _, ref trait_ref, ref typ, _) => {
 266                 let mut type_data = None;
 267                 let sub_span;
 268
 269                 let parent = self.tcx.map.get_enclosing_scope(item.id).unwrap_or(0);
 270
 271                 match typ.node {
 272                     // Common case impl for a struct or something basic.
 273                     ast::TyPath(None, ref path) => {
 274                         sub_span = self.span_utils.sub_span_for_type_name(path.span).unwrap();
 275                         type_data = self.lookup_ref_id(typ.id).map(|id| TypeRefData {
 276                             span: sub_span,
 277                             scope: parent,
 278                             ref_id: id,
 279                         });
 280                     },
 281                     _ => {
 282                         // Less useful case, impl for a compound type.
 283                         let span = typ.span;
 284                         sub_span = self.span_utils.sub_span_for_type_name(span).unwrap_or(span);
 285                     }
 286                 }
 287
 288                 let trait_data =
 289                     trait_ref.as_ref().and_then(|tr| self.get_trait_ref_data(tr, parent));
 290
 291                 Data::ImplData(ImplData {
 292                     id: item.id,
 293                     span: sub_span,
 294                     scope: parent,
 295                     trait_ref: trait_data,
 296                     self_ref: type_data,
 297                 })
 298             }
 299             _ => {
 300                 // FIXME
 301                 unimplemented!();
 302             }
 303         }
 304     }
 305
 306     // FIXME: we ought to be able to get the parent id ourselves, but we can't
 307     // for now.
 308     pub fn get_field_data(&self, field: &ast::StructField, parent: NodeId) -> Option<Data> {
 309         match field.node.kind {
 310             ast::NamedField(ident, _) => {
 311                 let name = get_ident(ident);
 312                 let qualname = format!("::{}::{}",
 313                                        self.tcx.map.path_to_string(parent),
 314                                        name);
 315                 let typ = self.tcx.node_types().get(&field.node.id).unwrap()
 316                                                .to_string();
 317                 let sub_span = self.span_utils.sub_span_before_token(field.span, token::Colon);
 318                 Some(Data::VariableData(VariableData {
 319                     id: field.node.id,
 320                     name: get_ident(ident).to_string(),
 321                     qualname: qualname,
 322                     span: sub_span.unwrap(),
 323                     scope: parent,
 324                     value: "".to_owned(),
 325                     type_value: typ,
 326                 }))
 327             },
 328             _ => None,
 329         }
 330     }
 331
 332     // FIXME: we ought to be able to get the parent id ourselves, but we can't
 333     // for now.
 334     pub fn get_trait_ref_data(&self,
 335                               trait_ref: &ast::TraitRef,
 336                               parent: NodeId)
 337                               -> Option<TypeRefData> {
 338         self.lookup_ref_id(trait_ref.ref_id).map(|def_id| {
 339             let span = trait_ref.path.span;
 340             let sub_span = self.span_utils.sub_span_for_type_name(span).unwrap_or(span);
 341             TypeRefData {
 342                 span: sub_span,
 343                 scope: parent,
 344                 ref_id: def_id,
 345             }
 346         })
 347     }
 348
 349     pub fn get_expr_data(&self, expr: &ast::Expr) -> Option<Data> {
 350         match expr.node {
 351             ast::ExprField(ref sub_ex, ident) => {
 352                 let ty = &self.tcx.expr_ty_adjusted(&sub_ex).sty;
 353                 match *ty {
 354                     ty::TyStruct(def_id, _) => {
 355                         let fields = self.tcx.lookup_struct_fields(def_id);
 356                         for f in &fields {
 357                             if f.name == ident.node.name {
 358                                 let sub_span = self.span_utils.span_for_last_ident(expr.span);
 359                                 return Some(Data::VariableRefData(VariableRefData {
 360                                     name: get_ident(ident.node).to_string(),
 361                                     span: sub_span.unwrap(),
 362                                     scope: self.tcx.map.get_enclosing_scope(expr.id).unwrap_or(0),
 363                                     ref_id: f.id,
 364                                 }));
 365                             }
 366                         }
 367
 368                         self.tcx.sess.span_bug(expr.span,
 369                                                &format!("Couldn't find field {} on {:?}",
 370                                                         &get_ident(ident.node), ty))
 371                     }
 372                     _ => {
 373                         debug!("Expected struct type, found {:?}", ty);
 374                         None
 375                     }
 376                 }
 377             }
 378             ast::ExprStruct(ref path, _, _) => {
 379                 let ty = &self.tcx.expr_ty_adjusted(expr).sty;
 380                 match *ty {
 381                     ty::TyStruct(def_id, _) => {
 382                         let sub_span = self.span_utils.span_for_last_ident(path.span);
 383                         Some(Data::TypeRefData(TypeRefData {
 384                             span: sub_span.unwrap(),
 385                             scope: self.tcx.map.get_enclosing_scope(expr.id).unwrap_or(0),
 386                             ref_id: def_id,
 387                         }))
 388                     }
 389                     _ => {
 390                         // FIXME ty could legitimately be a TyEnum, but then we will fail
 391                         // later if we try to look up the fields.
 392                         debug!("expected TyStruct, found {:?}", ty);
 393                         None
 394                     }
 395                 }
 396             }
 397             ast::ExprMethodCall(..) => {
 398                 let method_call = ty::MethodCall::expr(expr.id);
 399                 let method_id = self.tcx.tables.borrow().method_map[&method_call].def_id;
 400                 let (def_id, decl_id) = match self.tcx.impl_or_trait_item(method_id).container() {
 401                     ty::ImplContainer(_) => (Some(method_id), None),
 402                     ty::TraitContainer(_) => (None, Some(method_id))
 403                 };
 404                 let sub_span = self.span_utils.sub_span_for_meth_name(expr.span);
 405                 let parent = self.tcx.map.get_enclosing_scope(expr.id).unwrap_or(0);
 406                 Some(Data::MethodCallData(MethodCallData {
 407                     span: sub_span.unwrap(),
 408                     scope: parent,
 409                     ref_id: def_id,
 410                     decl_id: decl_id,
 411                 }))
 412             }
 413             ast::ExprPath(_, ref path) => {
 414                 Some(self.get_path_data(expr.id, path))
 415             }
 416             _ => {
 417                 // FIXME
 418                 unimplemented!();
 419             }
 420         }
 421     }
 422
 423     pub fn get_path_data(&self,
 424                          id: NodeId,
 425                          path: &ast::Path)
 426                          -> Data {
 427         let def_map = self.tcx.def_map.borrow();
 428         if !def_map.contains_key(&id) {
 429             self.tcx.sess.span_bug(path.span,
 430                                    &format!("def_map has no key for {} in visit_expr", id));
 431         }
 432         let def = def_map.get(&id).unwrap().full_def();
 433         let sub_span = self.span_utils.span_for_last_ident(path.span);
 434         match def {
 435             def::DefUpvar(..) |
 436             def::DefLocal(..) |
 437             def::DefStatic(..) |
 438             def::DefConst(..) |
 439             def::DefAssociatedConst(..) |
 440             def::DefVariant(..) => {
 441                 Data::VariableRefData(VariableRefData {
 442                     name: self.span_utils.snippet(sub_span.unwrap()),
 443                     span: sub_span.unwrap(),
 444                     scope: self.tcx.map.get_enclosing_scope(id).unwrap_or(0),
 445                     ref_id: def.def_id(),
 446                 })
 447             }
 448             def::DefStruct(def_id) | def::DefTy(def_id, _) => {
 449                 Data::TypeRefData(TypeRefData {
 450                     span: sub_span.unwrap(),
 451                     ref_id: def_id,
 452                     scope: self.tcx.map.get_enclosing_scope(id).unwrap_or(0),
 453                 })
 454             }
 455             def::DefMethod(decl_id, provenence) => {
 456                 let sub_span = self.span_utils.sub_span_for_meth_name(path.span);
 457                 let def_id = if decl_id.krate == ast::LOCAL_CRATE {
 458                     let ti = self.tcx.impl_or_trait_item(decl_id);
 459                     match provenence {
 460                         def::FromTrait(def_id) => {
 461                             Some(self.tcx.trait_items(def_id)
 462                                     .iter()
 463                                     .find(|mr| {
 464                                         mr.name() == ti.name()
 465                                     })
 466                                     .unwrap()
 467                                     .def_id())
 468                         }
 469                         def::FromImpl(def_id) => {
 470                             let impl_items = self.tcx.impl_items.borrow();
 471                             Some(impl_items.get(&def_id)
 472                                            .unwrap()
 473                                            .iter()
 474                                            .find(|mr| {
 475                                                 self.tcx.impl_or_trait_item(mr.def_id()).name()
 476                                                     == ti.name()
 477                                             })
 478                                            .unwrap()
 479                                            .def_id())
 480                         }
 481                     }
 482                 } else {
 483                     None
 484                 };
 485                 Data::MethodCallData(MethodCallData {
 486                     span: sub_span.unwrap(),
 487                     scope: self.tcx.map.get_enclosing_scope(id).unwrap_or(0),
 488                     ref_id: def_id,
 489                     decl_id: Some(decl_id),
 490                 })
 491             },
 492             def::DefFn(def_id, _) => {
 493                 Data::FunctionCallData(FunctionCallData {
 494                     ref_id: def_id,
 495                     span: sub_span.unwrap(),
 496                     scope: self.tcx.map.get_enclosing_scope(id).unwrap_or(0),
 497                 })
 498             }
 499             _ => self.tcx.sess.span_bug(path.span,
 500                                         &format!("Unexpected def kind while looking \
 501                                                   up path in `{}`: `{:?}`",
 502                                                  self.span_utils.snippet(path.span),
 503                                                  def)),
 504         }
 505     }
 506
 507     pub fn get_field_ref_data(&self,
 508                               field_ref: &ast::Field,
 509                               struct_id: DefId,
 510                               parent: NodeId)
 511                               -> VariableRefData {
 512         let fields = self.tcx.lookup_struct_fields(struct_id);
 513         let field_name = get_ident(field_ref.ident.node).to_string();
 514         for f in &fields {
 515             if f.name == field_ref.ident.node.name {
 516                 // We don't really need a sub-span here, but no harm done
 517                 let sub_span = self.span_utils.span_for_last_ident(field_ref.ident.span);
 518                 return VariableRefData {
 519                     name: field_name,
 520                     span: sub_span.unwrap(),
 521                     scope: parent,
 522                     ref_id: f.id,
 523                 };
 524             }
 525         }
 526
 527         self.tcx.sess.span_bug(field_ref.span,
 528                                &format!("Couldn't find field {}", field_name));
 529     }
 530
 531     pub fn get_data_for_id(&self, _id: &NodeId) -> Data {
 532         // FIXME
 533         unimplemented!();
 534     }
 535
 536     fn lookup_ref_id(&self, ref_id: NodeId) -> Option<DefId> {
 537         if !self.tcx.def_map.borrow().contains_key(&ref_id) {
 538             self.tcx.sess.bug(&format!("def_map has no key for {} in lookup_type_ref",
 539                                        ref_id));
 540         }
 541         let def = self.tcx.def_map.borrow().get(&ref_id).unwrap().full_def();
 542         match def {
 543             def::DefPrimTy(_) => None,
 544             _ => Some(def.def_id()),
 545         }
 546     }
 547
 548 }
 549
 550 // An AST visitor for collecting paths from patterns.
 551 struct PathCollector {
 552     // The Row field identifies the kind of pattern.
 553     collected_paths: Vec<(NodeId, ast::Path, ast::Mutability, recorder::Row)>,
 554 }
 555
 556 impl PathCollector {
 557     fn new() -> PathCollector {
 558         PathCollector {
 559             collected_paths: vec![],
 560         }
 561     }
 562 }
 563
 564 impl<'v> Visitor<'v> for PathCollector {
 565     fn visit_pat(&mut self, p: &ast::Pat) {
 566         if generated_code(p.span) {
 567             return;
 568         }
 569
 570         match p.node {
 571             ast::PatStruct(ref path, _, _) => {
 572                 self.collected_paths.push((p.id,
 573                                            path.clone(),
 574                                            ast::MutMutable,
 575                                            recorder::TypeRef));
 576             }
 577             ast::PatEnum(ref path, _) |
 578             ast::PatQPath(_, ref path) => {
 579                 self.collected_paths.push((p.id, path.clone(), ast::MutMutable, recorder::VarRef));
 580             }
 581             ast::PatIdent(bm, ref path1, _) => {
 582                 debug!("PathCollector, visit ident in pat {}: {:?} {:?}",
 583                        token::get_ident(path1.node),
 584                        p.span,
 585                        path1.span);
 586                 let immut = match bm {
 587                     // Even if the ref is mut, you can't change the ref, only
 588                     // the data pointed at, so showing the initialising expression
 589                     // is still worthwhile.
 590                     ast::BindByRef(_) => ast::MutImmutable,
 591                     ast::BindByValue(mt) => mt,
 592                 };
 593                 // collect path for either visit_local or visit_arm
 594                 let path = ast_util::ident_to_path(path1.span, path1.node);
 595                 self.collected_paths.push((p.id, path, immut, recorder::VarRef));
 596             }
 597             _ => {}
 598         }
 599         visit::walk_pat(self, p);
 600     }
 601 }
 602
 603 #[allow(deprecated)]
 604 pub fn process_crate(tcx: &ty::ctxt,
 605                      analysis: &ty::CrateAnalysis,
 606                      odir: Option<&Path>) {
 607     let krate = tcx.map.krate();
 608     if generated_code(krate.span) {
 609         return;
 610     }
 611
 612     assert!(analysis.glob_map.is_some());
 613     let cratename = match attr::find_crate_name(&krate.attrs) {
 614         Some(name) => name.to_string(),
 615         None => {
 616             info!("Could not find crate name, using 'unknown_crate'");
 617             String::from("unknown_crate")
 618         },
 619     };
 620
 621     info!("Dumping crate {}", cratename);
 622
 623     // find a path to dump our data to
 624     let mut root_path = match env::var_os("DXR_RUST_TEMP_FOLDER") {
 625         Some(val) => PathBuf::from(val),
 626         None => match odir {
 627             Some(val) => val.join("dxr"),
 628             None => PathBuf::from("dxr-temp"),
 629         },
 630     };
 631
 632     if let Err(e) = fs::create_dir_all(&root_path) {
 633         tcx.sess.err(&format!("Could not create directory {}: {}",
 634                               root_path.display(), e));
 635     }
 636
 637     {
 638         let disp = root_path.display();
 639         info!("Writing output to {}", disp);
 640     }
 641
 642     // Create output file.
 643     let mut out_name = cratename.clone();
 644     out_name.push_str(".csv");
 645     root_path.push(&out_name);
 646     let output_file = match File::create(&root_path) {
 647         Ok(f) => box f,
 648         Err(e) => {
 649             let disp = root_path.display();
 650             tcx.sess.fatal(&format!("Could not open {}: {}", disp, e));
 651         }
 652     };
 653     root_path.pop();
 654
 655     let mut visitor = dump_csv::DumpCsvVisitor::new(tcx, analysis, output_file);
 656
 657     visitor.dump_crate_info(&cratename, krate);
 658     visit::walk_crate(&mut visitor, krate);
 659 }
 660
 661 // Utility functions for the module.
 662
 663 // Helper function to escape quotes in a string
 664 fn escape(s: String) -> String {
 665     s.replace("\"", "\"\"")
 666 }
 667
 668 // If the expression is a macro expansion or other generated code, run screaming
 669 // and don't index.
 670 fn generated_code(span: Span) -> bool {
 671     span.expn_id != NO_EXPANSION || span  == DUMMY_SP
 672 }