src/librustc_driver/pretty.rs

// Copyright 2014 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.

//! The various pretty print routines.

pub use self::UserIdentifiedItem::*;
pub use self::PpSourceMode::*;
pub use self::PpMode::*;
use self::NodesMatchingUII::*;

use rustc_trans::back::link;

use driver;

use rustc::middle::ty;
use rustc::middle::cfg;
use rustc::middle::cfg::graphviz::LabelledCFG;
use rustc::session::Session;
use rustc::session::config::Input;
use rustc_borrowck as borrowck;
use rustc_borrowck::graphviz as borrowck_dot;
use rustc_resolve as resolve;
use rustc_metadata::cstore::CStore;

use syntax::ast;
use syntax::codemap;
use syntax::fold::{self, Folder};
use syntax::print::{pp, pprust};
use syntax::print::pprust::PrintState;
use syntax::ptr::P;
use syntax::util::small_vector::SmallVector;

use graphviz as dot;

use std::fs::File;
use std::io::{self, Write};
use std::option;
use std::path::PathBuf;
use std::str::FromStr;

use rustc::front::map as hir_map;
use rustc::front::map::{blocks, NodePrinter};
use rustc_front::hir;
use rustc_front::lowering::{lower_crate, LoweringContext};
use rustc_front::print::pprust as pprust_hir;

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum PpSourceMode {
    PpmNormal,
    PpmEveryBodyLoops,
    PpmExpanded,
    PpmIdentified,
    PpmExpandedIdentified,
    PpmExpandedHygiene,
    PpmTyped,
}

#[derive(Copy, Clone, PartialEq, Debug)]
pub enum PpFlowGraphMode {
    Default,
    /// Drops the labels from the edges in the flowgraph output. This
    /// is mostly for use in the --unpretty flowgraph run-make tests,
    /// since the labels are largely uninteresting in those cases and
    /// have become a pain to maintain.
    UnlabelledEdges,
}
#[derive(Copy, Clone, PartialEq, Debug)]
pub enum PpMode {
    PpmSource(PpSourceMode),
    PpmHir(PpSourceMode),
    PpmFlowGraph(PpFlowGraphMode),
}

pub fn parse_pretty(sess: &Session,
                    name: &str,
                    extended: bool)
                    -> (PpMode, Option<UserIdentifiedItem>) {
    let mut split = name.splitn(2, '=');
    let first = split.next().unwrap();
    let opt_second = split.next();
    let first = match (first, extended) {
        ("normal", _) => PpmSource(PpmNormal),
        ("identified", _) => PpmSource(PpmIdentified),
        ("everybody_loops", true) => PpmSource(PpmEveryBodyLoops),
        ("expanded", _) => PpmSource(PpmExpanded),
        ("expanded,identified", _) => PpmSource(PpmExpandedIdentified),
        ("expanded,hygiene", _) => PpmSource(PpmExpandedHygiene),
        ("hir", true) => PpmHir(PpmNormal),
        ("hir,identified", true) => PpmHir(PpmIdentified),
        ("hir,typed", true) => PpmHir(PpmTyped),
        ("flowgraph", true) => PpmFlowGraph(PpFlowGraphMode::Default),
        ("flowgraph,unlabelled", true) => PpmFlowGraph(PpFlowGraphMode::UnlabelledEdges),
        _ => {
            if extended {
                sess.fatal(&format!("argument to `unpretty` must be one of `normal`, \
                                     `expanded`, `flowgraph[,unlabelled]=<nodeid>`, \
                                     `identified`, `expanded,identified`, `everybody_loops`, \
                                     `hir`, `hir,identified`, or `hir,typed`; got {}",
                                    name));
            } else {
                sess.fatal(&format!("argument to `pretty` must be one of `normal`, `expanded`, \
                                     `identified`, or `expanded,identified`; got {}",
                                    name));
            }
        }
    };
    let opt_second = opt_second.and_then(|s| s.parse::<UserIdentifiedItem>().ok());
    (first, opt_second)
}



// This slightly awkward construction is to allow for each PpMode to
// choose whether it needs to do analyses (which can consume the
// Session) and then pass through the session (now attached to the
// analysis results) on to the chosen pretty-printer, along with the
// `&PpAnn` object.
//
// Note that since the `&PrinterSupport` is freshly constructed on each
// call, it would not make sense to try to attach the lifetime of `self`
// to the lifetime of the `&PrinterObject`.
//
// (The `use_once_payload` is working around the current lack of once
// functions in the compiler.)

impl PpSourceMode {
    /// Constructs a `PrinterSupport` object and passes it to `f`.
    fn call_with_pp_support<'tcx, A, B, F>(&self,
                                           sess: &'tcx Session,
                                           ast_map: Option<hir_map::Map<'tcx>>,
                                           payload: B,
                                           f: F)
                                           -> A
        where F: FnOnce(&PrinterSupport, B) -> A
    {
        match *self {
            PpmNormal | PpmEveryBodyLoops | PpmExpanded => {
                let annotation = NoAnn {
                    sess: sess,
                    ast_map: ast_map,
                };
                f(&annotation, payload)
            }

            PpmIdentified | PpmExpandedIdentified => {
                let annotation = IdentifiedAnnotation {
                    sess: sess,
                    ast_map: ast_map,
                };
                f(&annotation, payload)
            }
            PpmExpandedHygiene => {
                let annotation = HygieneAnnotation {
                    sess: sess,
                    ast_map: ast_map,
                };
                f(&annotation, payload)
            }
            _ => panic!("Should use call_with_pp_support_hir"),
        }
    }
    fn call_with_pp_support_hir<'tcx, A, B, F>(&self,
                                               sess: &'tcx Session,
                                               cstore: &CStore,
                                               ast_map: &hir_map::Map<'tcx>,
                                               arenas: &'tcx ty::CtxtArenas<'tcx>,
                                               id: &str,
                                               payload: B,
                                               f: F)
                                               -> A
        where F: FnOnce(&HirPrinterSupport, B, &hir::Crate) -> A
    {
        match *self {
            PpmNormal => {
                let annotation = NoAnn {
                    sess: sess,
                    ast_map: Some(ast_map.clone()),
                };
                f(&annotation, payload, &ast_map.forest.krate)
            }

            PpmIdentified => {
                let annotation = IdentifiedAnnotation {
                    sess: sess,
                    ast_map: Some(ast_map.clone()),
                };
                f(&annotation, payload, &ast_map.forest.krate)
            }
            PpmTyped => {
                driver::phase_3_run_analysis_passes(sess,
                                                    cstore,
                                                    ast_map.clone(),
                                                    arenas,
                                                    id,
                                                    resolve::MakeGlobMap::No,
                                                    |tcx, _, _| {
                                                        let annotation = TypedAnnotation {
                                                            tcx: tcx,
                                                        };
                                                        let _ignore = tcx.dep_graph.in_ignore();
                                                        f(&annotation,
                                                          payload,
                                                          &ast_map.forest.krate)
                                                    })
            }
            _ => panic!("Should use call_with_pp_support"),
        }
    }
}

trait PrinterSupport<'ast>: pprust::PpAnn {
    /// Provides a uniform interface for re-extracting a reference to a
    /// `Session` from a value that now owns it.
    fn sess<'a>(&'a self) -> &'a Session;

    /// Provides a uniform interface for re-extracting a reference to an
    /// `hir_map::Map` from a value that now owns it.
    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>>;

    /// Produces the pretty-print annotation object.
    ///
    /// (Rust does not yet support upcasting from a trait object to
    /// an object for one of its super-traits.)
    fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn;
}

trait HirPrinterSupport<'ast>: pprust_hir::PpAnn {
    /// Provides a uniform interface for re-extracting a reference to a
    /// `Session` from a value that now owns it.
    fn sess<'a>(&'a self) -> &'a Session;

    /// Provides a uniform interface for re-extracting a reference to an
    /// `hir_map::Map` from a value that now owns it.
    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>>;

    /// Produces the pretty-print annotation object.
    ///
    /// (Rust does not yet support upcasting from a trait object to
    /// an object for one of its super-traits.)
    fn pp_ann<'a>(&'a self) -> &'a pprust_hir::PpAnn;
}

struct NoAnn<'ast> {
    sess: &'ast Session,
    ast_map: Option<hir_map::Map<'ast>>,
}

impl<'ast> PrinterSupport<'ast> for NoAnn<'ast> {
    fn sess<'a>(&'a self) -> &'a Session {
        self.sess
    }

    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>> {
        self.ast_map.as_ref()
    }

    fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn {
        self
    }
}

impl<'ast> HirPrinterSupport<'ast> for NoAnn<'ast> {
    fn sess<'a>(&'a self) -> &'a Session {
        self.sess
    }

    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>> {
        self.ast_map.as_ref()
    }

    fn pp_ann<'a>(&'a self) -> &'a pprust_hir::PpAnn {
        self
    }
}

impl<'ast> pprust::PpAnn for NoAnn<'ast> {}
impl<'ast> pprust_hir::PpAnn for NoAnn<'ast> {}

struct IdentifiedAnnotation<'ast> {
    sess: &'ast Session,
    ast_map: Option<hir_map::Map<'ast>>,
}

impl<'ast> PrinterSupport<'ast> for IdentifiedAnnotation<'ast> {
    fn sess<'a>(&'a self) -> &'a Session {
        self.sess
    }

    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>> {
        self.ast_map.as_ref()
    }

    fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn {
        self
    }
}

impl<'ast> pprust::PpAnn for IdentifiedAnnotation<'ast> {
    fn pre(&self, s: &mut pprust::State, node: pprust::AnnNode) -> io::Result<()> {
        match node {
            pprust::NodeExpr(_) => s.popen(),
            _ => Ok(()),
        }
    }
    fn post(&self, s: &mut pprust::State, node: pprust::AnnNode) -> io::Result<()> {
        match node {
            pprust::NodeIdent(_) | pprust::NodeName(_) => Ok(()),

            pprust::NodeItem(item) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(item.id.to_string())
            }
            pprust::NodeSubItem(id) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(id.to_string())
            }
            pprust::NodeBlock(blk) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(format!("block {}", blk.id))
            }
            pprust::NodeExpr(expr) => {
                try!(pp::space(&mut s.s));
                try!(s.synth_comment(expr.id.to_string()));
                s.pclose()
            }
            pprust::NodePat(pat) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(format!("pat {}", pat.id))
            }
        }
    }
}

impl<'ast> HirPrinterSupport<'ast> for IdentifiedAnnotation<'ast> {
    fn sess<'a>(&'a self) -> &'a Session {
        self.sess
    }

    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>> {
        self.ast_map.as_ref()
    }

    fn pp_ann<'a>(&'a self) -> &'a pprust_hir::PpAnn {
        self
    }
}

impl<'ast> pprust_hir::PpAnn for IdentifiedAnnotation<'ast> {
    fn pre(&self, s: &mut pprust_hir::State, node: pprust_hir::AnnNode) -> io::Result<()> {
        match node {
            pprust_hir::NodeExpr(_) => s.popen(),
            _ => Ok(()),
        }
    }
    fn post(&self, s: &mut pprust_hir::State, node: pprust_hir::AnnNode) -> io::Result<()> {
        match node {
            pprust_hir::NodeName(_) => Ok(()),
            pprust_hir::NodeItem(item) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(item.id.to_string())
            }
            pprust_hir::NodeSubItem(id) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(id.to_string())
            }
            pprust_hir::NodeBlock(blk) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(format!("block {}", blk.id))
            }
            pprust_hir::NodeExpr(expr) => {
                try!(pp::space(&mut s.s));
                try!(s.synth_comment(expr.id.to_string()));
                s.pclose()
            }
            pprust_hir::NodePat(pat) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(format!("pat {}", pat.id))
            }
        }
    }
}

struct HygieneAnnotation<'ast> {
    sess: &'ast Session,
    ast_map: Option<hir_map::Map<'ast>>,
}

impl<'ast> PrinterSupport<'ast> for HygieneAnnotation<'ast> {
    fn sess<'a>(&'a self) -> &'a Session {
        self.sess
    }

    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'ast>> {
        self.ast_map.as_ref()
    }

    fn pp_ann<'a>(&'a self) -> &'a pprust::PpAnn {
        self
    }
}

impl<'ast> pprust::PpAnn for HygieneAnnotation<'ast> {
    fn post(&self, s: &mut pprust::State, node: pprust::AnnNode) -> io::Result<()> {
        match node {
            pprust::NodeIdent(&ast::Ident { name: ast::Name(nm), ctxt }) => {
                try!(pp::space(&mut s.s));
                // FIXME #16420: this doesn't display the connections
                // between syntax contexts
                s.synth_comment(format!("{}#{}", nm, ctxt.0))
            }
            pprust::NodeName(&ast::Name(nm)) => {
                try!(pp::space(&mut s.s));
                s.synth_comment(nm.to_string())
            }
            _ => Ok(()),
        }
    }
}


struct TypedAnnotation<'a, 'tcx: 'a> {
    tcx: &'a ty::ctxt<'tcx>,
}

impl<'b, 'tcx> HirPrinterSupport<'tcx> for TypedAnnotation<'b, 'tcx> {
    fn sess<'a>(&'a self) -> &'a Session {
        &self.tcx.sess
    }

    fn ast_map<'a>(&'a self) -> Option<&'a hir_map::Map<'tcx>> {
        Some(&self.tcx.map)
    }

    fn pp_ann<'a>(&'a self) -> &'a pprust_hir::PpAnn {
        self
    }
}

impl<'a, 'tcx> pprust_hir::PpAnn for TypedAnnotation<'a, 'tcx> {
    fn pre(&self, s: &mut pprust_hir::State, node: pprust_hir::AnnNode) -> io::Result<()> {
        match node {
            pprust_hir::NodeExpr(_) => s.popen(),
            _ => Ok(()),
        }
    }
    fn post(&self, s: &mut pprust_hir::State, node: pprust_hir::AnnNode) -> io::Result<()> {
        match node {
            pprust_hir::NodeExpr(expr) => {
                try!(pp::space(&mut s.s));
                try!(pp::word(&mut s.s, "as"));
                try!(pp::space(&mut s.s));
                try!(pp::word(&mut s.s, &self.tcx.expr_ty(expr).to_string()));
                s.pclose()
            }
            _ => Ok(()),
        }
    }
}

fn gather_flowgraph_variants(sess: &Session) -> Vec<borrowck_dot::Variant> {
    let print_loans = sess.opts.debugging_opts.flowgraph_print_loans;
    let print_moves = sess.opts.debugging_opts.flowgraph_print_moves;
    let print_assigns = sess.opts.debugging_opts.flowgraph_print_assigns;
    let print_all = sess.opts.debugging_opts.flowgraph_print_all;
    let mut variants = Vec::new();
    if print_all || print_loans {
        variants.push(borrowck_dot::Loans);
    }
    if print_all || print_moves {
        variants.push(borrowck_dot::Moves);
    }
    if print_all || print_assigns {
        variants.push(borrowck_dot::Assigns);
    }
    variants
}

#[derive(Clone, Debug)]
pub enum UserIdentifiedItem {
    ItemViaNode(ast::NodeId),
    ItemViaPath(Vec<String>),
}

impl FromStr for UserIdentifiedItem {
    type Err = ();
    fn from_str(s: &str) -> Result<UserIdentifiedItem, ()> {
        Ok(s.parse()
            .map(ItemViaNode)
            .unwrap_or_else(|_| ItemViaPath(s.split("::").map(|s| s.to_string()).collect())))
    }
}

enum NodesMatchingUII<'a, 'ast: 'a> {
    NodesMatchingDirect(option::IntoIter<ast::NodeId>),
    NodesMatchingSuffix(hir_map::NodesMatchingSuffix<'a, 'ast>),
}

impl<'a, 'ast> Iterator for NodesMatchingUII<'a, 'ast> {
    type Item = ast::NodeId;

    fn next(&mut self) -> Option<ast::NodeId> {
        match self {
            &mut NodesMatchingDirect(ref mut iter) => iter.next(),
            &mut NodesMatchingSuffix(ref mut iter) => iter.next(),
        }
    }
}

impl UserIdentifiedItem {
    fn reconstructed_input(&self) -> String {
        match *self {
            ItemViaNode(node_id) => node_id.to_string(),
            ItemViaPath(ref parts) => parts.join("::"),
        }
    }

    fn all_matching_node_ids<'a, 'ast>(&'a self,
                                       map: &'a hir_map::Map<'ast>)
                                       -> NodesMatchingUII<'a, 'ast> {
        match *self {
            ItemViaNode(node_id) => NodesMatchingDirect(Some(node_id).into_iter()),
            ItemViaPath(ref parts) => NodesMatchingSuffix(map.nodes_matching_suffix(&parts[..])),
        }
    }

    fn to_one_node_id(self, user_option: &str, sess: &Session, map: &hir_map::Map) -> ast::NodeId {
        let fail_because = |is_wrong_because| -> ast::NodeId {
            let message = format!("{} needs NodeId (int) or unique path suffix (b::c::d); got \
                                   {}, which {}",
                                  user_option,
                                  self.reconstructed_input(),
                                  is_wrong_because);
            sess.fatal(&message[..])
        };

        let mut saw_node = ast::DUMMY_NODE_ID;
        let mut seen = 0;
        for node in self.all_matching_node_ids(map) {
            saw_node = node;
            seen += 1;
            if seen > 1 {
                fail_because("does not resolve uniquely");
            }
        }
        if seen == 0 {
            fail_because("does not resolve to any item");
        }

        assert!(seen == 1);
        return saw_node;
    }
}

fn needs_ast_map(ppm: &PpMode, opt_uii: &Option<UserIdentifiedItem>) -> bool {
    match *ppm {
        PpmSource(PpmNormal) |
        PpmSource(PpmEveryBodyLoops) |
        PpmSource(PpmIdentified) => opt_uii.is_some(),

        PpmSource(PpmExpanded) |
        PpmSource(PpmExpandedIdentified) |
        PpmSource(PpmExpandedHygiene) |
        PpmHir(_) |
        PpmFlowGraph(_) => true,
        PpmSource(PpmTyped) => panic!("invalid state"),
    }
}

fn needs_expansion(ppm: &PpMode) -> bool {
    match *ppm {
        PpmSource(PpmNormal) |
        PpmSource(PpmEveryBodyLoops) |
        PpmSource(PpmIdentified) => false,

        PpmSource(PpmExpanded) |
        PpmSource(PpmExpandedIdentified) |
        PpmSource(PpmExpandedHygiene) |
        PpmHir(_) |
        PpmFlowGraph(_) => true,
        PpmSource(PpmTyped) => panic!("invalid state"),
    }
}

struct ReplaceBodyWithLoop {
    within_static_or_const: bool,
}

impl ReplaceBodyWithLoop {
    fn new() -> ReplaceBodyWithLoop {
        ReplaceBodyWithLoop { within_static_or_const: false }
    }
}

impl fold::Folder for ReplaceBodyWithLoop {
    fn fold_item_underscore(&mut self, i: ast::Item_) -> ast::Item_ {
        match i {
            ast::ItemStatic(..) | ast::ItemConst(..) => {
                self.within_static_or_const = true;
                let ret = fold::noop_fold_item_underscore(i, self);
                self.within_static_or_const = false;
                return ret;
            }
            _ => {
                fold::noop_fold_item_underscore(i, self)
            }
        }
    }

    fn fold_trait_item(&mut self, i: P<ast::TraitItem>) -> SmallVector<P<ast::TraitItem>> {
        match i.node {
            ast::ConstTraitItem(..) => {
                self.within_static_or_const = true;
                let ret = fold::noop_fold_trait_item(i, self);
                self.within_static_or_const = false;
                return ret;
            }
            _ => fold::noop_fold_trait_item(i, self),
        }
    }

    fn fold_impl_item(&mut self, i: P<ast::ImplItem>) -> SmallVector<P<ast::ImplItem>> {
        match i.node {
            ast::ImplItemKind::Const(..) => {
                self.within_static_or_const = true;
                let ret = fold::noop_fold_impl_item(i, self);
                self.within_static_or_const = false;
                return ret;
            }
            _ => fold::noop_fold_impl_item(i, self),
        }
    }

    fn fold_block(&mut self, b: P<ast::Block>) -> P<ast::Block> {
        fn expr_to_block(rules: ast::BlockCheckMode, e: Option<P<ast::Expr>>) -> P<ast::Block> {
            P(ast::Block {
                expr: e,
                stmts: vec![],
                rules: rules,
                id: ast::DUMMY_NODE_ID,
                span: codemap::DUMMY_SP,
            })
        }

        if !self.within_static_or_const {

            let empty_block = expr_to_block(ast::DefaultBlock, None);
            let loop_expr = P(ast::Expr {
                node: ast::ExprLoop(empty_block, None),
                id: ast::DUMMY_NODE_ID,
                span: codemap::DUMMY_SP,
                attrs: None,
            });

            expr_to_block(b.rules, Some(loop_expr))

        } else {
            fold::noop_fold_block(b, self)
        }
    }

    // in general the pretty printer processes unexpanded code, so
    // we override the default `fold_mac` method which panics.
    fn fold_mac(&mut self, mac: ast::Mac) -> ast::Mac {
        fold::noop_fold_mac(mac, self)
    }
}

pub fn pretty_print_input(sess: Session,
                          cstore: &CStore,
                          cfg: ast::CrateConfig,
                          input: &Input,
                          ppm: PpMode,
                          opt_uii: Option<UserIdentifiedItem>,
                          ofile: Option<PathBuf>) {
    let krate = driver::phase_1_parse_input(&sess, cfg, input);

    let krate = if let PpmSource(PpmEveryBodyLoops) = ppm {
        let mut fold = ReplaceBodyWithLoop::new();
        fold.fold_crate(krate)
    } else {
        krate
    };

    let id = link::find_crate_name(Some(&sess), &krate.attrs, input);

    let is_expanded = needs_expansion(&ppm);
    let compute_ast_map = needs_ast_map(&ppm, &opt_uii);
    let krate = if compute_ast_map {
        match driver::phase_2_configure_and_expand(&sess, &cstore, krate, &id[..], None) {
            None => return,
            Some(k) => driver::assign_node_ids(&sess, k),
        }
    } else {
        krate
    };

    // There is some twisted, god-forsaken tangle of lifetimes here which makes
    // the ordering of stuff super-finicky.
    let mut hir_forest;
    let lcx = LoweringContext::new(&sess, Some(&krate));
    let arenas = ty::CtxtArenas::new();
    let ast_map = if compute_ast_map {
        hir_forest = hir_map::Forest::new(lower_crate(&lcx, &krate));
        let map = driver::make_map(&sess, &mut hir_forest);
        Some(map)
    } else {
        None
    };

    let src_name = driver::source_name(input);
    let src = sess.codemap()
                  .get_filemap(&src_name[..])
                  .src
                  .as_ref()
                  .unwrap()
                  .as_bytes()
                  .to_vec();
    let mut rdr = &src[..];

    let mut out = Vec::new();

    match (ppm, opt_uii) {
        (PpmSource(s), _) => {
            // Silently ignores an identified node.
            let out: &mut Write = &mut out;
            s.call_with_pp_support(&sess, ast_map, box out, |annotation, out| {
                debug!("pretty printing source code {:?}", s);
                let sess = annotation.sess();
                pprust::print_crate(sess.codemap(),
                                    sess.diagnostic(),
                                    &krate,
                                    src_name.to_string(),
                                    &mut rdr,
                                    out,
                                    annotation.pp_ann(),
                                    is_expanded)
            })
        }

        (PpmHir(s), None) => {
            let out: &mut Write = &mut out;
            s.call_with_pp_support_hir(&sess,
                                       cstore,
                                       &ast_map.unwrap(),
                                       &arenas,
                                       &id,
                                       box out,
                                       |annotation, out, krate| {
                                           debug!("pretty printing source code {:?}", s);
                                           let sess = annotation.sess();
                                           pprust_hir::print_crate(sess.codemap(),
                                                                   sess.diagnostic(),
                                                                   krate,
                                                                   src_name.to_string(),
                                                                   &mut rdr,
                                                                   out,
                                                                   annotation.pp_ann(),
                                                                   is_expanded)
                                       })
        }

        (PpmHir(s), Some(uii)) => {
            let out: &mut Write = &mut out;
            s.call_with_pp_support_hir(&sess,
                                       cstore,
                                       &ast_map.unwrap(),
                                       &arenas,
                                       &id,
                                       (out,uii),
                                       |annotation, (out,uii), _| {
                debug!("pretty printing source code {:?}", s);
                let sess = annotation.sess();
                let ast_map = annotation.ast_map().expect("--pretty missing ast_map");
                let mut pp_state =
                    pprust_hir::State::new_from_input(sess.codemap(),
                                                      sess.diagnostic(),
                                                      src_name.to_string(),
                                                      &mut rdr,
                                                      box out,
                                                      annotation.pp_ann(),
                                                      true,
                                                      Some(ast_map.krate()));
                for node_id in uii.all_matching_node_ids(ast_map) {
                    let node = ast_map.get(node_id);
                    try!(pp_state.print_node(&node));
                    try!(pp::space(&mut pp_state.s));
                    try!(pp_state.synth_comment(ast_map.path_to_string(node_id)));
                    try!(pp::hardbreak(&mut pp_state.s));
                }
                pp::eof(&mut pp_state.s)
            })
        }

        (PpmFlowGraph(mode), opt_uii) => {
            debug!("pretty printing flow graph for {:?}", opt_uii);
            let uii = opt_uii.unwrap_or_else(|| {
                sess.fatal(&format!("`pretty flowgraph=..` needs NodeId (int) or
                                     \
                                     unique path suffix (b::c::d)"))

            });
            let ast_map = ast_map.expect("--pretty flowgraph missing ast_map");
            let nodeid = uii.to_one_node_id("--pretty", &sess, &ast_map);

            let node = ast_map.find(nodeid).unwrap_or_else(|| {
                sess.fatal(&format!("--pretty flowgraph couldn't find id: {}", nodeid))
            });

            let code = blocks::Code::from_node(node);
            let out: &mut Write = &mut out;
            match code {
                Some(code) => {
                    let variants = gather_flowgraph_variants(&sess);
                    driver::phase_3_run_analysis_passes(&sess,
                                                        &cstore,
                                                        ast_map,
                                                        &arenas,
                                                        &id,
                                                        resolve::MakeGlobMap::No,
                                                        |tcx, _, _| {
                                                            print_flowgraph(variants,
                                                                            tcx,
                                                                            code,
                                                                            mode,
                                                                            out)
                                                        })
                }
                None => {
                    let message = format!("--pretty=flowgraph needs block, fn, or method; got \
                                           {:?}",
                                          node);

                    // point to what was found, if there's an
                    // accessible span.
                    match ast_map.opt_span(nodeid) {
                        Some(sp) => sess.span_fatal(sp, &message[..]),
                        None => sess.fatal(&message[..]),
                    }
                }
            }
        }
    }
    .unwrap();

    match ofile {
        None => print!("{}", String::from_utf8(out).unwrap()),
        Some(p) => {
            match File::create(&p) {
                Ok(mut w) => w.write_all(&out).unwrap(),
                Err(e) => panic!("print-print failed to open {} due to {}", p.display(), e),
            }
        }
    }
}

fn print_flowgraph<W: Write>(variants: Vec<borrowck_dot::Variant>,
                             tcx: &ty::ctxt,
                             code: blocks::Code,
                             mode: PpFlowGraphMode,
                             mut out: W)
                             -> io::Result<()> {
    let cfg = match code {
        blocks::BlockCode(block) => cfg::CFG::new(tcx, &*block),
        blocks::FnLikeCode(fn_like) => cfg::CFG::new(tcx, &*fn_like.body()),
    };
    let labelled_edges = mode != PpFlowGraphMode::UnlabelledEdges;
    let lcfg = LabelledCFG {
        ast_map: &tcx.map,
        cfg: &cfg,
        name: format!("node_{}", code.id()),
        labelled_edges: labelled_edges,
    };

    match code {
        _ if variants.is_empty() => {
            let r = dot::render(&lcfg, &mut out);
            return expand_err_details(r);
        }
        blocks::BlockCode(_) => {
            tcx.sess.err("--pretty flowgraph with -Z flowgraph-print annotations requires \
                          fn-like node id.");
            return Ok(());
        }
        blocks::FnLikeCode(fn_like) => {
            let (bccx, analysis_data) =
                borrowck::build_borrowck_dataflow_data_for_fn(tcx,
                                                              fn_like.to_fn_parts(),
                                                              &cfg);

            let lcfg = borrowck_dot::DataflowLabeller {
                inner: lcfg,
                variants: variants,
                borrowck_ctxt: &bccx,
                analysis_data: &analysis_data,
            };
            let r = dot::render(&lcfg, &mut out);
            return expand_err_details(r);
        }
    }

    fn expand_err_details(r: io::Result<()>) -> io::Result<()> {
        r.map_err(|ioerr| {
            io::Error::new(io::ErrorKind::Other,
                           &format!("graphviz::render failed: {}", ioerr)[..])
        })
    }
}