rust/src/librustc_trans/save/dump_csv.rs

// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.

//! Output a CSV file containing the output from rustc's analysis. The data is
//! primarily designed to be used as input to the DXR tool, specifically its
//! Rust plugin. It could also be used by IDEs or other code browsing, search, or
//! cross-referencing tools.
//!
//! Dumping the analysis is implemented by walking the AST and getting a bunch of
//! info out from all over the place. We use Def IDs to identify objects. The
//! tricky part is getting syntactic (span, source text) and semantic (reference
//! Def IDs) information for parts of expressions which the compiler has discarded.
//! E.g., in a path `foo::bar::baz`, the compiler only keeps a span for the whole
//! path and a reference to `baz`, but we want spans and references for all three
//! idents.
//!
//! SpanUtils is used to manipulate spans. In particular, to extract sub-spans
//! from spans (e.g., the span for `bar` from the above example path).
//! Recorder is used for recording the output in csv format. FmtStrs separates
//! the format of the output away from extracting it from the compiler.
//! DumpCsvVisitor walks the AST and processes it.


use super::{escape, generated_code, recorder, SaveContext, PathCollector};

use session::Session;

use middle::def;
use middle::ty::{self, Ty};
use rustc::ast_map::NodeItem;

use std::cell::Cell;
use std::fs::File;
use std::path::Path;

use syntax::ast_util;
use syntax::ast::{self, NodeId, DefId};
use syntax::codemap::*;
use syntax::parse::token::{self, get_ident, keywords};
use syntax::owned_slice::OwnedSlice;
use syntax::visit::{self, Visitor};
use syntax::print::pprust::{path_to_string, ty_to_string};
use syntax::ptr::P;

use super::span_utils::SpanUtils;
use super::recorder::{Recorder, FmtStrs};

use util::ppaux;


pub struct DumpCsvVisitor<'l, 'tcx: 'l> {
    save_ctxt: SaveContext<'l, 'tcx>,
    sess: &'l Session,
    analysis: &'l ty::CrateAnalysis<'tcx>,

    span: SpanUtils<'l>,
    fmt: FmtStrs<'l>,

    cur_scope: NodeId
}

impl <'l, 'tcx> DumpCsvVisitor<'l, 'tcx> {
    pub fn new(sess: &'l Session,
               analysis: &'l ty::CrateAnalysis<'tcx>,
               output_file: Box<File>) -> DumpCsvVisitor<'l, 'tcx> {
        DumpCsvVisitor {
            sess: sess,
            save_ctxt: SaveContext::new(sess, analysis, SpanUtils {
                sess: sess,
                err_count: Cell::new(0)
            }),
            analysis: analysis,
            span: SpanUtils {
                sess: sess,
                err_count: Cell::new(0)
            },
            fmt: FmtStrs::new(box Recorder {
                                out: output_file,
                                dump_spans: false,
                            },
                            SpanUtils {
                                sess: sess,
                                err_count: Cell::new(0)
                            }),
            cur_scope: 0
        }
    }

    fn nest<F>(&mut self, scope_id: NodeId, f: F) where
        F: FnOnce(&mut DumpCsvVisitor<'l, 'tcx>),
    {
        let parent_scope = self.cur_scope;
        self.cur_scope = scope_id;
        f(self);
        self.cur_scope = parent_scope;
    }

    pub fn dump_crate_info(&mut self, name: &str, krate: &ast::Crate) {
        // The current crate.
        self.fmt.crate_str(krate.span, name);

        // Dump info about all the external crates referenced from this crate.
        for c in &self.save_ctxt.get_external_crates() {
            self.fmt.external_crate_str(krate.span, &c.name, c.number);
        }
        self.fmt.recorder.record("end_external_crates\n");
    }

    // Return all non-empty prefixes of a path.
    // For each prefix, we return the span for the last segment in the prefix and
    // a str representation of the entire prefix.
    fn process_path_prefixes(&self, path: &ast::Path) -> Vec<(Span, String)> {
        let spans = self.span.spans_for_path_segments(path);

        // Paths to enums seem to not match their spans - the span includes all the
        // variants too. But they seem to always be at the end, so I hope we can cope with
        // always using the first ones. So, only error out if we don't have enough spans.
        // What could go wrong...?
        if spans.len() < path.segments.len() {
            error!("Mis-calculated spans for path '{}'. \
                    Found {} spans, expected {}. Found spans:",
                   path_to_string(path), spans.len(), path.segments.len());
            for s in &spans {
                let loc = self.sess.codemap().lookup_char_pos(s.lo);
                error!("    '{}' in {}, line {}",
                       self.span.snippet(*s), loc.file.name, loc.line);
            }
            return vec!();
        }

        let mut result: Vec<(Span, String)> = vec!();

        let mut segs = vec!();
        for (i, (seg, span)) in path.segments.iter().zip(&spans).enumerate() {
            segs.push(seg.clone());
            let sub_path = ast::Path{span: *span, // span for the last segment
                                     global: path.global,
                                     segments: segs};
            let qualname = if i == 0 && path.global {
                format!("::{}", path_to_string(&sub_path))
            } else {
                path_to_string(&sub_path)
            };
            result.push((*span, qualname));
            segs = sub_path.segments;
        }

        result
    }

    // The global arg allows us to override the global-ness of the path (which
    // actually means 'does the path start with `::`', rather than 'is the path
    // semantically global). We use the override for `use` imports (etc.) where
    // the syntax is non-global, but the semantics are global.
    fn write_sub_paths(&mut self, path: &ast::Path, global: bool) {
        let sub_paths = self.process_path_prefixes(path);
        for (i, &(ref span, ref qualname)) in sub_paths.iter().enumerate() {
            let qualname = if i == 0 && global && !path.global {
                format!("::{}", qualname)
            } else {
                qualname.clone()
            };
            self.fmt.sub_mod_ref_str(path.span,
                                     *span,
                                     &qualname,
                                     self.cur_scope);
        }
    }

    // As write_sub_paths, but does not process the last ident in the path (assuming it
    // will be processed elsewhere). See note on write_sub_paths about global.
    fn write_sub_paths_truncated(&mut self, path: &ast::Path, global: bool) {
        let sub_paths = self.process_path_prefixes(path);
        let len = sub_paths.len();
        if len <= 1 {
            return;
        }

        let sub_paths = &sub_paths[..len-1];
        for (i, &(ref span, ref qualname)) in sub_paths.iter().enumerate() {
            let qualname = if i == 0 && global && !path.global {
                format!("::{}", qualname)
            } else {
                qualname.clone()
            };
            self.fmt.sub_mod_ref_str(path.span,
                                     *span,
                                     &qualname,
                                     self.cur_scope);
        }
    }

    // As write_sub_paths, but expects a path of the form module_path::trait::method
    // Where trait could actually be a struct too.
    fn write_sub_path_trait_truncated(&mut self, path: &ast::Path) {
        let sub_paths = self.process_path_prefixes(path);
        let len = sub_paths.len();
        if len <= 1 {
            return;
        }
        let sub_paths = &sub_paths[.. (len-1)];

        // write the trait part of the sub-path
        let (ref span, ref qualname) = sub_paths[len-2];
        self.fmt.sub_type_ref_str(path.span,
                                  *span,
                                  &qualname);

        // write the other sub-paths
        if len <= 2 {
            return;
        }
        let sub_paths = &sub_paths[..len-2];
        for &(ref span, ref qualname) in sub_paths {
            self.fmt.sub_mod_ref_str(path.span,
                                     *span,
                                     &qualname,
                                     self.cur_scope);
        }
    }

    // looks up anything, not just a type
    fn lookup_type_ref(&self, ref_id: NodeId) -> Option<DefId> {
        if !self.analysis.ty_cx.def_map.borrow().contains_key(&ref_id) {
            self.sess.bug(&format!("def_map has no key for {} in lookup_type_ref",
                                  ref_id));
        }
        let def = self.analysis.ty_cx.def_map.borrow().get(&ref_id).unwrap().full_def();
        match def {
            def::DefPrimTy(_) => None,
            _ => Some(def.def_id()),
        }
    }

    fn lookup_def_kind(&self, ref_id: NodeId, span: Span) -> Option<recorder::Row> {
        let def_map = self.analysis.ty_cx.def_map.borrow();
        if !def_map.contains_key(&ref_id) {
            self.sess.span_bug(span, &format!("def_map has no key for {} in lookup_def_kind",
                                             ref_id));
        }
        let def = def_map.get(&ref_id).unwrap().full_def();
        match def {
            def::DefMod(_) |
            def::DefForeignMod(_) => Some(recorder::ModRef),
            def::DefStruct(_) => Some(recorder::StructRef),
            def::DefTy(..) |
            def::DefAssociatedTy(..) |
            def::DefTrait(_) => Some(recorder::TypeRef),
            def::DefStatic(_, _) |
            def::DefConst(_) |
            def::DefAssociatedConst(..) |
            def::DefLocal(_) |
            def::DefVariant(_, _, _) |
            def::DefUpvar(..) => Some(recorder::VarRef),

            def::DefFn(..) => Some(recorder::FnRef),

            def::DefSelfTy(..) |
            def::DefRegion(_) |
            def::DefLabel(_) |
            def::DefTyParam(..) |
            def::DefUse(_) |
            def::DefMethod(..) |
            def::DefPrimTy(_) => {
                self.sess.span_bug(span, &format!("lookup_def_kind for unexpected item: {:?}",
                                                 def));
            },
        }
    }

    fn process_formals(&mut self, formals: &Vec<ast::Arg>, qualname: &str) {
        for arg in formals {
            self.visit_pat(&arg.pat);
            let mut collector = PathCollector::new();
            collector.visit_pat(&arg.pat);
            let span_utils = self.span.clone();
            for &(id, ref p, _, _) in &collector.collected_paths {
                let typ =
                    ppaux::ty_to_string(
                        &self.analysis.ty_cx,
                        *self.analysis.ty_cx.node_types().get(&id).unwrap());
                // get the span only for the name of the variable (I hope the path is only ever a
                // variable name, but who knows?)
                self.fmt.formal_str(p.span,
                                    span_utils.span_for_last_ident(p.span),
                                    id,
                                    qualname,
                                    &path_to_string(p),
                                    &typ);
            }
        }
    }

    fn process_method(&mut self, sig: &ast::MethodSig,
                      body: Option<&ast::Block>,
                      id: ast::NodeId, name: ast::Name,
                      span: Span) {
        if generated_code(span) {
            return;
        }

        debug!("process_method: {}:{}", id, token::get_name(name));

        let mut scope_id;
        // The qualname for a method is the trait name or name of the struct in an impl in
        // which the method is declared in, followed by the method's name.
        let qualname = match ty::impl_of_method(&self.analysis.ty_cx,
                                                ast_util::local_def(id)) {
            Some(impl_id) => match self.analysis.ty_cx.map.get(impl_id.node) {
                NodeItem(item) => {
                    scope_id = item.id;
                    match item.node {
                        ast::ItemImpl(_, _, _, _, ref ty, _) => {
                            let mut result = String::from("<");
                            result.push_str(&ty_to_string(&**ty));

                            match ty::trait_of_item(&self.analysis.ty_cx,
                                                    ast_util::local_def(id)) {
                                Some(def_id) => {
                                    result.push_str(" as ");
                                    result.push_str(
                                        &ty::item_path_str(&self.analysis.ty_cx, def_id));
                                },
                                None => {}
                            }
                            result.push_str(">");
                            result
                        }
                        _ => {
                            self.sess.span_bug(span,
                                &format!("Container {} for method {} not an impl?",
                                         impl_id.node, id));
                        },
                    }
                },
                _ => {
                    self.sess.span_bug(span,
                        &format!("Container {} for method {} is not a node item {:?}",
                                 impl_id.node, id, self.analysis.ty_cx.map.get(impl_id.node)));
                },
            },
            None => match ty::trait_of_item(&self.analysis.ty_cx,
                                            ast_util::local_def(id)) {
                Some(def_id) => {
                    scope_id = def_id.node;
                    match self.analysis.ty_cx.map.get(def_id.node) {
                        NodeItem(_) => {
                            format!("::{}", ty::item_path_str(&self.analysis.ty_cx, def_id))
                        }
                        _ => {
                            self.sess.span_bug(span,
                                &format!("Could not find container {} for method {}",
                                         def_id.node, id));
                        }
                    }
                },
                None => {
                    self.sess.span_bug(span,
                        &format!("Could not find container for method {}", id));
                },
            },
        };

        let qualname = &format!("{}::{}", qualname, &token::get_name(name));

        // record the decl for this def (if it has one)
        let decl_id = ty::trait_item_of_item(&self.analysis.ty_cx,
                                             ast_util::local_def(id))
            .and_then(|new_id| {
                let def_id = new_id.def_id();
                if def_id.node != 0 && def_id != ast_util::local_def(id) {
                    Some(def_id)
                } else {
                    None
                }
            });

        let sub_span = self.span.sub_span_after_keyword(span, keywords::Fn);
        if body.is_some() {
            self.fmt.method_str(span,
                                sub_span,
                                id,
                                qualname,
                                decl_id,
                                scope_id);
            self.process_formals(&sig.decl.inputs, qualname);
        } else {
            self.fmt.method_decl_str(span,
                                     sub_span,
                                     id,
                                     qualname,
                                     scope_id);
        }

        // walk arg and return types
        for arg in &sig.decl.inputs {
            self.visit_ty(&arg.ty);
        }

        if let ast::Return(ref ret_ty) = sig.decl.output {
            self.visit_ty(ret_ty);
        }

        // walk the fn body
        if let Some(body) = body {
            self.nest(id, |v| v.visit_block(body));
        }

        self.process_generic_params(&sig.generics,
                                    span,
                                    qualname,
                                    id);
    }

    fn process_trait_ref(&mut self,
                         trait_ref: &ast::TraitRef) {
        match self.lookup_type_ref(trait_ref.ref_id) {
            Some(id) => {
                let sub_span = self.span.sub_span_for_type_name(trait_ref.path.span);
                self.fmt.ref_str(recorder::TypeRef,
                                 trait_ref.path.span,
                                 sub_span,
                                 id,
                                 self.cur_scope);
                visit::walk_path(self, &trait_ref.path);
            },
            None => ()
        }
    }

    fn process_struct_field_def(&mut self,
                                field: &ast::StructField,
                                parent_id: NodeId) {
        let field_data = self.save_ctxt.get_field_data(field, parent_id);
        if let Some(field_data) = field_data {
            if let super::Data::VariableData(field_data) = field_data {
                self.fmt.field_str(field.span,
                                   Some(field_data.span),
                                   field_data.id,
                                   &field_data.name,
                                   &field_data.qualname,
                                   &field_data.type_value,
                                   field_data.scope);
            } else {
                self.sess.span_bug(field.span, "expected VariableData");
            }
        }
    }

    // Dump generic params bindings, then visit_generics
    fn process_generic_params(&mut self,
                              generics:&ast::Generics,
                              full_span: Span,
                              prefix: &str,
                              id: NodeId) {
        // We can't only use visit_generics since we don't have spans for param
        // bindings, so we reparse the full_span to get those sub spans.
        // However full span is the entire enum/fn/struct block, so we only want
        // the first few to match the number of generics we're looking for.
        let param_sub_spans = self.span.spans_for_ty_params(full_span,
                                                           (generics.ty_params.len() as isize));
        for (param, param_ss) in generics.ty_params.iter().zip(param_sub_spans) {
            // Append $id to name to make sure each one is unique
            let name = format!("{}::{}${}",
                               prefix,
                               escape(self.span.snippet(param_ss)),
                               id);
            self.fmt.typedef_str(full_span,
                                 Some(param_ss),
                                 param.id,
                                 &name,
                                 "");
        }
        self.visit_generics(generics);
    }

    fn process_fn(&mut self,
                  item: &ast::Item,
                  decl: &ast::FnDecl,
                  ty_params: &ast::Generics,
                  body: &ast::Block) {
        let fn_data = self.save_ctxt.get_item_data(item);
        if let super::Data::FunctionData(fn_data) = fn_data {
            self.fmt.fn_str(item.span,
                            Some(fn_data.span),
                            fn_data.id,
                            &fn_data.qualname,
                            fn_data.scope);


            self.process_formals(&decl.inputs, &fn_data.qualname);
            self.process_generic_params(ty_params, item.span, &fn_data.qualname, item.id);
        } else {
            self.sess.span_bug(item.span, "expected FunctionData");
        }

        for arg in &decl.inputs {
            self.visit_ty(&arg.ty);
        }

        if let ast::Return(ref ret_ty) = decl.output {
            self.visit_ty(&ret_ty);
        }

        self.nest(item.id, |v| v.visit_block(&body));
    }

    fn process_static_or_const_item(&mut self,
                                    item: &ast::Item,
                                    typ: &ast::Ty,
                                    expr: &ast::Expr)
    {
        let var_data = self.save_ctxt.get_item_data(item);
        if let super::Data::VariableData(var_data) = var_data {
            self.fmt.static_str(item.span,
                                Some(var_data.span),
                                var_data.id,
                                &var_data.name,
                                &var_data.qualname,
                                &var_data.value,
                                &var_data.type_value,
                                var_data.scope);
        } else {
            self.sess.span_bug(item.span, "expected VariableData");
        }

        self.visit_ty(&typ);
        self.visit_expr(expr);
    }

    fn process_const(&mut self,
                     id: ast::NodeId,
                     ident: &ast::Ident,
                     span: Span,
                     typ: &ast::Ty,
                     expr: &ast::Expr)
    {
        let qualname = format!("::{}", self.analysis.ty_cx.map.path_to_string(id));

        let sub_span = self.span.sub_span_after_keyword(span,
                                                        keywords::Const);

        self.fmt.static_str(span,
                            sub_span,
                            id,
                            &get_ident((*ident).clone()),
                            &qualname,
                            &self.span.snippet(expr.span),
                            &ty_to_string(&*typ),
                            self.cur_scope);

        // walk type and init value
        self.visit_ty(typ);
        self.visit_expr(expr);
    }

    fn process_struct(&mut self,
                      item: &ast::Item,
                      def: &ast::StructDef,
                      ty_params: &ast::Generics) {
        let qualname = format!("::{}", self.analysis.ty_cx.map.path_to_string(item.id));

        let ctor_id = match def.ctor_id {
            Some(node_id) => node_id,
            None => -1,
        };
        let val = self.span.snippet(item.span);
        let sub_span = self.span.sub_span_after_keyword(item.span, keywords::Struct);
        self.fmt.struct_str(item.span,
                            sub_span,
                            item.id,
                            ctor_id,
                            &qualname,
                            self.cur_scope,
                            &val);

        // fields
        for field in &def.fields {
            self.process_struct_field_def(field, item.id);
            self.visit_ty(&field.node.ty);
        }

        self.process_generic_params(ty_params, item.span, &qualname, item.id);
    }

    fn process_enum(&mut self,
                    item: &ast::Item,
                    enum_definition: &ast::EnumDef,
                    ty_params: &ast::Generics) {
        let enum_data = self.save_ctxt.get_item_data(item);
        if let super::Data::EnumData(enum_data) = enum_data {
            self.fmt.enum_str(item.span,
                              Some(enum_data.span),
                              enum_data.id,
                              &enum_data.qualname,
                              self.cur_scope,
                              &enum_data.value);
            for variant in &enum_definition.variants {
                let name = &get_ident(variant.node.name);
                let mut qualname = enum_data.qualname.clone();
                qualname.push_str("::");
                qualname.push_str(name);
                let val = self.span.snippet(variant.span);
                match variant.node.kind {
                    ast::TupleVariantKind(ref args) => {
                        // first ident in span is the variant's name
                        self.fmt.tuple_variant_str(variant.span,
                                                   self.span.span_for_first_ident(variant.span),
                                                   variant.node.id,
                                                   name,
                                                   &qualname,
                                                   &enum_data.qualname,
                                                   &val,
                                                   item.id);
                        for arg in args {
                            self.visit_ty(&*arg.ty);
                        }
                    }
                    ast::StructVariantKind(ref struct_def) => {
                        let ctor_id = match struct_def.ctor_id {
                            Some(node_id) => node_id,
                            None => -1,
                        };
                        self.fmt.struct_variant_str(variant.span,
                                                    self.span.span_for_first_ident(variant.span),
                                                    variant.node.id,
                                                    ctor_id,
                                                    &qualname,
                                                    &enum_data.qualname,
                                                    &val,
                                                    item.id);

                        for field in &struct_def.fields {
                            self.process_struct_field_def(field, variant.node.id);
                            self.visit_ty(&*field.node.ty);
                        }
                    }
                }
            }
            self.process_generic_params(ty_params, item.span, &enum_data.qualname, item.id);
        } else {
            self.sess.span_bug(item.span, "expected EnumData");
        }
    }

    fn process_impl(&mut self,
                    item: &ast::Item,
                    type_parameters: &ast::Generics,
                    trait_ref: &Option<ast::TraitRef>,
                    typ: &ast::Ty,
                    impl_items: &[P<ast::ImplItem>]) {
        let trait_id = trait_ref.as_ref().and_then(|tr| self.lookup_type_ref(tr.ref_id));
        match typ.node {
            // Common case impl for a struct or something basic.
            ast::TyPath(None, ref path) => {
                let sub_span = self.span.sub_span_for_type_name(path.span);
                let self_id = self.lookup_type_ref(typ.id).map(|id| {
                    self.fmt.ref_str(recorder::TypeRef,
                                     path.span,
                                     sub_span,
                                     id,
                                     self.cur_scope);
                    id
                });
                self.fmt.impl_str(path.span,
                                  sub_span,
                                  item.id,
                                  self_id,
                                  trait_id,
                                  self.cur_scope);
            },
            _ => {
                // Less useful case, impl for a compound type.
                self.visit_ty(&*typ);

                let sub_span = self.span.sub_span_for_type_name(typ.span);
                self.fmt.impl_str(typ.span,
                                  sub_span,
                                  item.id,
                                  None,
                                  trait_id,
                                  self.cur_scope);
            }
        }

        match *trait_ref {
            Some(ref trait_ref) => self.process_trait_ref(trait_ref),
            None => (),
        }

        self.process_generic_params(type_parameters, item.span, "", item.id);
        for impl_item in impl_items {
            self.visit_impl_item(impl_item);
        }
    }

    fn process_trait(&mut self,
                     item: &ast::Item,
                     generics: &ast::Generics,
                     trait_refs: &OwnedSlice<ast::TyParamBound>,
                     methods: &[P<ast::TraitItem>]) {
        let qualname = format!("::{}", self.analysis.ty_cx.map.path_to_string(item.id));
        let val = self.span.snippet(item.span);
        let sub_span = self.span.sub_span_after_keyword(item.span, keywords::Trait);
        self.fmt.trait_str(item.span,
                           sub_span,
                           item.id,
                           &qualname,
                           self.cur_scope,
                           &val);

        // super-traits
        for super_bound in trait_refs.iter() {
            let trait_ref = match *super_bound {
                ast::TraitTyParamBound(ref trait_ref, _) => {
                    trait_ref
                }
                ast::RegionTyParamBound(..) => {
                    continue;
                }
            };

            let trait_ref = &trait_ref.trait_ref;
            match self.lookup_type_ref(trait_ref.ref_id) {
                Some(id) => {
                    let sub_span = self.span.sub_span_for_type_name(trait_ref.path.span);
                    self.fmt.ref_str(recorder::TypeRef,
                                     trait_ref.path.span,
                                     sub_span,
                                     id,
                                     self.cur_scope);
                    self.fmt.inherit_str(trait_ref.path.span,
                                         sub_span,
                                         id,
                                         item.id);
                },
                None => ()
            }
        }

        // walk generics and methods
        self.process_generic_params(generics, item.span, &qualname, item.id);
        for method in methods {
            self.visit_trait_item(method)
        }
    }

    fn process_mod(&mut self,
                   item: &ast::Item) {  // The module in question, represented as an item.
        let mod_data = self.save_ctxt.get_item_data(item);
        if let super::Data::ModData(mod_data) = mod_data {
            self.fmt.mod_str(item.span,
                             Some(mod_data.span),
                             mod_data.id,
                             &mod_data.qualname,
                             mod_data.scope,
                             &mod_data.filename);
        } else {
            self.sess.span_bug(item.span, "expected ModData");
        }
    }

    fn process_path(&mut self,
                    id: NodeId,
                    span: Span,
                    path: &ast::Path,
                    ref_kind: Option<recorder::Row>) {
        if generated_code(span) {
            return
        }

        let def_map = self.analysis.ty_cx.def_map.borrow();
        if !def_map.contains_key(&id) {
            self.sess.span_bug(span,
                               &format!("def_map has no key for {} in visit_expr", id));
        }
        let def = def_map.get(&id).unwrap().full_def();
        let sub_span = self.span.span_for_last_ident(span);
        match def {
            def::DefUpvar(..) |
            def::DefLocal(..) |
            def::DefStatic(..) |
            def::DefConst(..) |
            def::DefAssociatedConst(..) |
            def::DefVariant(..) => self.fmt.ref_str(ref_kind.unwrap_or(recorder::VarRef),
                                                    span,
                                                    sub_span,
                                                    def.def_id(),
                                                    self.cur_scope),
            def::DefStruct(def_id) => self.fmt.ref_str(recorder::StructRef,
                                                       span,
                                                       sub_span,
                                                       def_id,
                                                       self.cur_scope),
            def::DefTy(def_id, _) => self.fmt.ref_str(recorder::TypeRef,
                                                      span,
                                                      sub_span,
                                                      def_id,
                                                      self.cur_scope),
            def::DefMethod(declid, provenence) => {
                let sub_span = self.span.sub_span_for_meth_name(span);
                let defid = if declid.krate == ast::LOCAL_CRATE {
                    let ti = ty::impl_or_trait_item(&self.analysis.ty_cx,
                                                    declid);
                    match provenence {
                        def::FromTrait(def_id) => {
                            Some(ty::trait_items(&self.analysis.ty_cx,
                                                 def_id)
                                    .iter()
                                    .find(|mr| {
                                        mr.name() == ti.name()
                                    })
                                    .unwrap()
                                    .def_id())
                        }
                        def::FromImpl(def_id) => {
                            let impl_items = self.analysis
                                                 .ty_cx
                                                 .impl_items
                                                 .borrow();
                            Some(impl_items.get(&def_id)
                                           .unwrap()
                                           .iter()
                                           .find(|mr| {
                                                ty::impl_or_trait_item(
                                                    &self.analysis.ty_cx,
                                                    mr.def_id()
                                                ).name() == ti.name()
                                            })
                                           .unwrap()
                                           .def_id())
                        }
                    }
                } else {
                    None
                };
                self.fmt.meth_call_str(span,
                                       sub_span,
                                       defid,
                                       Some(declid),
                                       self.cur_scope);
            },
            def::DefFn(def_id, _) => {
                self.fmt.fn_call_str(span,
                                     sub_span,
                                     def_id,
                                     self.cur_scope)
            }
            _ => self.sess.span_bug(span,
                                    &format!("Unexpected def kind while looking \
                                              up path in `{}`: `{:?}`",
                                             self.span.snippet(span),
                                             def)),
        }
        // modules or types in the path prefix
        match def {
            def::DefMethod(did, _) => {
                let ti = ty::impl_or_trait_item(&self.analysis.ty_cx, did);
                if let ty::MethodTraitItem(m) = ti {
                    if m.explicit_self == ty::StaticExplicitSelfCategory {
                        self.write_sub_path_trait_truncated(path);
                    }
                }
            }
            def::DefLocal(_) |
            def::DefStatic(_,_) |
            def::DefConst(..) |
            def::DefAssociatedConst(..) |
            def::DefStruct(_) |
            def::DefVariant(..) |
            def::DefFn(..) => self.write_sub_paths_truncated(path, false),
            _ => {},
        }
    }

    fn process_struct_lit(&mut self,
                          ex: &ast::Expr,
                          path: &ast::Path,
                          fields: &Vec<ast::Field>,
                          base: &Option<P<ast::Expr>>) {
        if generated_code(path.span) {
            return
        }

        self.write_sub_paths_truncated(path, false);

        let ty = &ty::expr_ty_adjusted(&self.analysis.ty_cx, ex).sty;
        let struct_def = match *ty {
            ty::TyStruct(def_id, _) => {
                let sub_span = self.span.span_for_last_ident(path.span);
                self.fmt.ref_str(recorder::StructRef,
                                 path.span,
                                 sub_span,
                                 def_id,
                                 self.cur_scope);
                Some(def_id)
            }
            _ => None
        };

        for field in fields {
            match struct_def {
                Some(struct_def) => {
                    let fields = ty::lookup_struct_fields(&self.analysis.ty_cx, struct_def);
                    for f in &fields {
                        if generated_code(field.ident.span) {
                            continue;
                        }
                        if f.name == field.ident.node.name {
                            // We don't really need a sub-span here, but no harm done
                            let sub_span = self.span.span_for_last_ident(field.ident.span);
                            self.fmt.ref_str(recorder::VarRef,
                                             field.ident.span,
                                             sub_span,
                                             f.id,
                                             self.cur_scope);
                        }
                    }
                }
                None => {}
            }

            self.visit_expr(&*field.expr)
        }
        visit::walk_expr_opt(self, base)
    }

    fn process_method_call(&mut self,
                           ex: &ast::Expr,
                           args: &Vec<P<ast::Expr>>) {
        let method_map = self.analysis.ty_cx.method_map.borrow();
        let method_callee = method_map.get(&ty::MethodCall::expr(ex.id)).unwrap();
        let (def_id, decl_id) = match method_callee.origin {
            ty::MethodStatic(def_id) |
            ty::MethodStaticClosure(def_id) => {
                // method invoked on an object with a concrete type (not a static method)
                let decl_id =
                    match ty::trait_item_of_item(&self.analysis.ty_cx,
                                                 def_id) {
                        None => None,
                        Some(decl_id) => Some(decl_id.def_id()),
                    };

                // This incantation is required if the method referenced is a
                // trait's default implementation.
                let def_id = match ty::impl_or_trait_item(&self.analysis
                                                               .ty_cx,
                                                          def_id) {
                    ty::MethodTraitItem(method) => {
                        method.provided_source.unwrap_or(def_id)
                    }
                    _ => self.sess
                             .span_bug(ex.span,
                                       "save::process_method_call: non-method \
                                        DefId in MethodStatic or MethodStaticClosure"),
                };
                (Some(def_id), decl_id)
            }
            ty::MethodTypeParam(ref mp) => {
                // method invoked on a type parameter
                let trait_item = ty::trait_item(&self.analysis.ty_cx,
                                                mp.trait_ref.def_id,
                                                mp.method_num);
                (None, Some(trait_item.def_id()))
            }
            ty::MethodTraitObject(ref mo) => {
                // method invoked on a trait instance
                let trait_item = ty::trait_item(&self.analysis.ty_cx,
                                                mo.trait_ref.def_id,
                                                mo.method_num);
                (None, Some(trait_item.def_id()))
            }
        };
        let sub_span = self.span.sub_span_for_meth_name(ex.span);
        self.fmt.meth_call_str(ex.span,
                               sub_span,
                               def_id,
                               decl_id,
                               self.cur_scope);

        // walk receiver and args
        visit::walk_exprs(self, &args);
    }

    fn process_pat(&mut self, p:&ast::Pat) {
        if generated_code(p.span) {
            return
        }

        match p.node {
            ast::PatStruct(ref path, ref fields, _) => {
                visit::walk_path(self, path);

                let def = self.analysis.ty_cx.def_map.borrow().get(&p.id).unwrap().full_def();
                let struct_def = match def {
                    def::DefConst(..) | def::DefAssociatedConst(..) => None,
                    def::DefVariant(_, variant_id, _) => Some(variant_id),
                    _ => {
                        match ty::ty_to_def_id(ty::node_id_to_type(&self.analysis.ty_cx, p.id)) {
                            None => {
                                self.sess.span_bug(p.span,
                                                   &format!("Could not find struct_def for `{}`",
                                                            self.span.snippet(p.span)));
                            }
                            Some(def_id) => Some(def_id),
                        }
                    }
                };

                if let Some(struct_def) = struct_def {
                    let struct_fields = ty::lookup_struct_fields(&self.analysis.ty_cx, struct_def);
                    for &Spanned { node: ref field, span } in fields {
                        let sub_span = self.span.span_for_first_ident(span);
                        for f in &struct_fields {
                            if f.name == field.ident.name {
                                self.fmt.ref_str(recorder::VarRef,
                                                 span,
                                                 sub_span,
                                                 f.id,
                                                 self.cur_scope);
                                break;
                            }
                        }
                        self.visit_pat(&*field.pat);
                    }
                }
            }
            _ => visit::walk_pat(self, p)
        }
    }
}

impl<'l, 'tcx, 'v> Visitor<'v> for DumpCsvVisitor<'l, 'tcx> {
    fn visit_item(&mut self, item: &ast::Item) {
        if generated_code(item.span) {
            return
        }

        match item.node {
            ast::ItemUse(ref use_item) => {
                match use_item.node {
                    ast::ViewPathSimple(ident, ref path) => {
                        let sub_span = self.span.span_for_last_ident(path.span);
                        let mod_id = match self.lookup_type_ref(item.id) {
                            Some(def_id) => {
                                match self.lookup_def_kind(item.id, path.span) {
                                    Some(kind) => self.fmt.ref_str(kind,
                                                                   path.span,
                                                                   sub_span,
                                                                   def_id,
                                                                   self.cur_scope),
                                    None => {},
                                }
                                Some(def_id)
                            },
                            None => None,
                        };

                        // 'use' always introduces an alias, if there is not an explicit
                        // one, there is an implicit one.
                        let sub_span =
                            match self.span.sub_span_after_keyword(use_item.span, keywords::As) {
                                Some(sub_span) => Some(sub_span),
                                None => sub_span,
                            };

                        self.fmt.use_alias_str(path.span,
                                               sub_span,
                                               item.id,
                                               mod_id,
                                               &get_ident(ident),
                                               self.cur_scope);
                        self.write_sub_paths_truncated(path, true);
                    }
                    ast::ViewPathGlob(ref path) => {
                        // Make a comma-separated list of names of imported modules.
                        let mut name_string = String::new();
                        let glob_map = &self.analysis.glob_map;
                        let glob_map = glob_map.as_ref().unwrap();
                        if glob_map.contains_key(&item.id) {
                            for n in glob_map.get(&item.id).unwrap() {
                                if !name_string.is_empty() {
                                    name_string.push_str(", ");
                                }
                                name_string.push_str(n.as_str());
                            }
                        }

                        let sub_span = self.span.sub_span_of_token(path.span,
                                                                   token::BinOp(token::Star));
                        self.fmt.use_glob_str(path.span,
                                              sub_span,
                                              item.id,
                                              &name_string,
                                              self.cur_scope);
                        self.write_sub_paths(path, true);
                    }
                    ast::ViewPathList(ref path, ref list) => {
                        for plid in list {
                            match plid.node {
                                ast::PathListIdent { id, .. } => {
                                    match self.lookup_type_ref(id) {
                                        Some(def_id) =>
                                            match self.lookup_def_kind(id, plid.span) {
                                                Some(kind) => {
                                                    self.fmt.ref_str(
                                                        kind, plid.span,
                                                        Some(plid.span),
                                                        def_id, self.cur_scope);
                                                }
                                                None => ()
                                            },
                                        None => ()
                                    }
                                },
                                ast::PathListMod { .. } => ()
                            }
                        }

                        self.write_sub_paths(path, true);
                    }
                }
            }
            ast::ItemExternCrate(ref s) => {
                let name = get_ident(item.ident);
                let name = &name;
                let location = match *s {
                    Some(s) => s.to_string(),
                    None => name.to_string(),
                };
                let alias_span = self.span.span_for_last_ident(item.span);
                let cnum = match self.sess.cstore.find_extern_mod_stmt_cnum(item.id) {
                    Some(cnum) => cnum,
                    None => 0,
                };
                self.fmt.extern_crate_str(item.span,
                                          alias_span,
                                          item.id,
                                          cnum,
                                          name,
                                          &location,
                                          self.cur_scope);
            }
            ast::ItemFn(ref decl, _, _, _, ref ty_params, ref body) =>
                self.process_fn(item, &**decl, ty_params, &**body),
            ast::ItemStatic(ref typ, _, ref expr) =>
                self.process_static_or_const_item(item, typ, expr),
            ast::ItemConst(ref typ, ref expr) =>
                self.process_static_or_const_item(item, &typ, &expr),
            ast::ItemStruct(ref def, ref ty_params) => self.process_struct(item, &**def, ty_params),
            ast::ItemEnum(ref def, ref ty_params) => self.process_enum(item, def, ty_params),
            ast::ItemImpl(_, _,
                          ref ty_params,
                          ref trait_ref,
                          ref typ,
                          ref impl_items) => {
                self.process_impl(item,
                                  ty_params,
                                  trait_ref,
                                  &**typ,
                                  impl_items)
            }
            ast::ItemTrait(_, ref generics, ref trait_refs, ref methods) =>
                self.process_trait(item, generics, trait_refs, methods),
            ast::ItemMod(ref m) => {
                self.process_mod(item);
                self.nest(item.id, |v| visit::walk_mod(v, m));
            }
            ast::ItemTy(ref ty, ref ty_params) => {
                let qualname = format!("::{}", self.analysis.ty_cx.map.path_to_string(item.id));
                let value = ty_to_string(&**ty);
                let sub_span = self.span.sub_span_after_keyword(item.span, keywords::Type);
                self.fmt.typedef_str(item.span,
                                     sub_span,
                                     item.id,
                                     &qualname,
                                     &value);

                self.visit_ty(&**ty);
                self.process_generic_params(ty_params, item.span, &qualname, item.id);
            },
            ast::ItemMac(_) => (),
            _ => visit::walk_item(self, item),
        }
    }

    fn visit_generics(&mut self, generics: &ast::Generics) {
        for param in generics.ty_params.iter() {
            for bound in param.bounds.iter() {
                if let ast::TraitTyParamBound(ref trait_ref, _) = *bound {
                    self.process_trait_ref(&trait_ref.trait_ref);
                }
            }
            if let Some(ref ty) = param.default {
                self.visit_ty(&**ty);
            }
        }
    }

    fn visit_trait_item(&mut self, trait_item: &ast::TraitItem) {
        match trait_item.node {
            ast::ConstTraitItem(ref ty, Some(ref expr)) => {
                self.process_const(trait_item.id, &trait_item.ident,
                                   trait_item.span, &*ty, &*expr);
            }
            ast::MethodTraitItem(ref sig, ref body) => {
                self.process_method(sig, body.as_ref().map(|x| &**x),
                                    trait_item.id, trait_item.ident.name, trait_item.span);
            }
            ast::ConstTraitItem(_, None) |
            ast::TypeTraitItem(..) => {}
        }
    }

    fn visit_impl_item(&mut self, impl_item: &ast::ImplItem) {
        match impl_item.node {
            ast::ConstImplItem(ref ty, ref expr) => {
                self.process_const(impl_item.id, &impl_item.ident,
                                   impl_item.span, &ty, &expr);
            }
            ast::MethodImplItem(ref sig, ref body) => {
                self.process_method(sig, Some(body), impl_item.id,
                                    impl_item.ident.name, impl_item.span);
            }
            ast::TypeImplItem(_) |
            ast::MacImplItem(_) => {}
        }
    }

    fn visit_ty(&mut self, t: &ast::Ty) {
        if generated_code(t.span) {
            return
        }

        match t.node {
            ast::TyPath(_, ref path) => {
                match self.lookup_type_ref(t.id) {
                    Some(id) => {
                        let sub_span = self.span.sub_span_for_type_name(t.span);
                        self.fmt.ref_str(recorder::TypeRef,
                                         t.span,
                                         sub_span,
                                         id,
                                         self.cur_scope);
                    },
                    None => ()
                }

                self.write_sub_paths_truncated(path, false);

                visit::walk_path(self, path);
            },
            _ => visit::walk_ty(self, t),
        }
    }

    fn visit_expr(&mut self, ex: &ast::Expr) {
        if generated_code(ex.span) {
            return
        }

        match ex.node {
            ast::ExprCall(ref _f, ref _args) => {
                // Don't need to do anything for function calls,
                // because just walking the callee path does what we want.
                visit::walk_expr(self, ex);
            }
            ast::ExprPath(_, ref path) => {
                self.process_path(ex.id, path.span, path, None);
                visit::walk_expr(self, ex);
            }
            ast::ExprStruct(ref path, ref fields, ref base) =>
                self.process_struct_lit(ex, path, fields, base),
            ast::ExprMethodCall(_, _, ref args) => self.process_method_call(ex, args),
            ast::ExprField(ref sub_ex, _) => {
                if generated_code(sub_ex.span) {
                    return
                }

                self.visit_expr(&sub_ex);

                let field_data = self.save_ctxt.get_expr_data(ex);
                if let super::Data::VariableRefData(field_data) = field_data {
                    self.fmt.ref_str(recorder::VarRef,
                                     ex.span,
                                     Some(field_data.span),
                                     field_data.ref_id,
                                     field_data.scope);
                } else {
                    self.sess.span_bug(ex.span, "expected VariableRefData");
                }
            },
            ast::ExprTupField(ref sub_ex, idx) => {
                if generated_code(sub_ex.span) {
                    return
                }

                self.visit_expr(&**sub_ex);

                let ty = &ty::expr_ty_adjusted(&self.analysis.ty_cx, &**sub_ex).sty;
                match *ty {
                    ty::TyStruct(def_id, _) => {
                        let fields = ty::lookup_struct_fields(&self.analysis.ty_cx, def_id);
                        for (i, f) in fields.iter().enumerate() {
                            if i == idx.node {
                                let sub_span = self.span.sub_span_after_token(ex.span, token::Dot);
                                self.fmt.ref_str(recorder::VarRef,
                                                 ex.span,
                                                 sub_span,
                                                 f.id,
                                                 self.cur_scope);
                                break;
                            }
                        }
                    }
                    ty::TyTuple(_) => {}
                    _ => self.sess.span_bug(ex.span,
                                            &format!("Expected struct or tuple \
                                                      type, found {:?}", ty)),
                }
            },
            ast::ExprClosure(_, ref decl, ref body) => {
                if generated_code(body.span) {
                    return
                }

                let mut id = String::from("$");
                id.push_str(&ex.id.to_string());
                self.process_formals(&decl.inputs, &id);

                // walk arg and return types
                for arg in &decl.inputs {
                    self.visit_ty(&*arg.ty);
                }

                if let ast::Return(ref ret_ty) = decl.output {
                    self.visit_ty(&**ret_ty);
                }

                // walk the body
                self.nest(ex.id, |v| v.visit_block(&**body));
            },
            _ => {
                visit::walk_expr(self, ex)
            }
        }
    }

    fn visit_mac(&mut self, _: &ast::Mac) {
        // Just stop, macros are poison to us.
    }

    fn visit_pat(&mut self, p: &ast::Pat) {
        self.process_pat(p);
    }

    fn visit_arm(&mut self, arm: &ast::Arm) {
        let mut collector = PathCollector::new();
        for pattern in &arm.pats {
            // collect paths from the arm's patterns
            collector.visit_pat(&pattern);
            self.visit_pat(&pattern);
        }

        // This is to get around borrow checking, because we need mut self to call process_path.
        let mut paths_to_process = vec![];
        // process collected paths
        for &(id, ref p, immut, ref_kind) in &collector.collected_paths {
            let def_map = self.analysis.ty_cx.def_map.borrow();
            if !def_map.contains_key(&id) {
                self.sess.span_bug(p.span,
                                   &format!("def_map has no key for {} in visit_arm",
                                           id));
            }
            let def = def_map.get(&id).unwrap().full_def();
            match def {
                def::DefLocal(id)  => {
                    let value = if immut == ast::MutImmutable {
                        self.span.snippet(p.span).to_string()
                    } else {
                        "<mutable>".to_string()
                    };

                    assert!(p.segments.len() == 1, "qualified path for local variable def in arm");
                    self.fmt.variable_str(p.span,
                                          Some(p.span),
                                          id,
                                          &path_to_string(p),
                                          &value,
                                          "")
                }
                def::DefVariant(..) | def::DefTy(..) | def::DefStruct(..) => {
                    paths_to_process.push((id, p.clone(), Some(ref_kind)))
                }
                // FIXME(nrc) what are these doing here?
                def::DefStatic(_, _) |
                def::DefConst(..) |
                def::DefAssociatedConst(..) => {}
                _ => error!("unexpected definition kind when processing collected paths: {:?}",
                            def)
            }
        }
        for &(id, ref path, ref_kind) in &paths_to_process {
            self.process_path(id, path.span, path, ref_kind);
        }
        visit::walk_expr_opt(self, &arm.guard);
        self.visit_expr(&*arm.body);
    }

    fn visit_stmt(&mut self, s: &ast::Stmt) {
        if generated_code(s.span) {
            return
        }

        visit::walk_stmt(self, s)
    }

    fn visit_local(&mut self, l: &ast::Local) {
        if generated_code(l.span) {
            return
        }

        // The local could declare multiple new vars, we must walk the
        // pattern and collect them all.
        let mut collector = PathCollector::new();
        collector.visit_pat(&l.pat);
        self.visit_pat(&l.pat);

        let value = self.span.snippet(l.span);

        for &(id, ref p, immut, _) in &collector.collected_paths {
            let value = if immut == ast::MutImmutable {
                value.to_string()
            } else {
                "<mutable>".to_string()
            };
            let types = self.analysis.ty_cx.node_types();
            let typ = ppaux::ty_to_string(&self.analysis.ty_cx, *types.get(&id).unwrap());
            // Get the span only for the name of the variable (I hope the path
            // is only ever a variable name, but who knows?).
            let sub_span = self.span.span_for_last_ident(p.span);
            // Rust uses the id of the pattern for var lookups, so we'll use it too.
            self.fmt.variable_str(p.span,
                                  sub_span,
                                  id,
                                  &path_to_string(p),
                                  &value,
                                  &typ);
        }

        // Just walk the initialiser and type (don't want to walk the pattern again).
        visit::walk_ty_opt(self, &l.ty);
        visit::walk_expr_opt(self, &l.init);
    }
}