rust/compiler/rustc_driver_impl/src/pretty.rs

//! The various pretty-printing routines.

use rustc_ast as ast;
use rustc_ast_pretty::pprust as pprust_ast;
use rustc_hir as hir;
use rustc_hir_pretty as pprust_hir;
use rustc_middle::bug;
use rustc_middle::hir::map as hir_map;
use rustc_middle::mir::{write_mir_graphviz, write_mir_pretty};
use rustc_middle::ty::{self, TyCtxt};
use rustc_session::config::{OutFileName, PpHirMode, PpMode, PpSourceMode};
use rustc_session::Session;
use rustc_span::symbol::Ident;
use rustc_span::FileName;

use std::cell::Cell;
use std::fmt::Write;

pub use self::PpMode::*;
pub use self::PpSourceMode::*;
use crate::abort_on_err;

// 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 `&AstPrinterSupport` 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`.

/// Constructs an `AstPrinterSupport` object and passes it to `f`.
fn call_with_pp_support_ast<'tcx, A, F>(
    ppmode: &PpSourceMode,
    sess: &'tcx Session,
    tcx: Option<TyCtxt<'tcx>>,
    f: F,
) -> A
where
    F: FnOnce(&dyn AstPrinterSupport) -> A,
{
    match *ppmode {
        Normal | Expanded => {
            let annotation = NoAnn { sess, tcx };
            f(&annotation)
        }
        Identified | ExpandedIdentified => {
            let annotation = IdentifiedAnnotation { sess, tcx };
            f(&annotation)
        }
        ExpandedHygiene => {
            let annotation = HygieneAnnotation { sess };
            f(&annotation)
        }
    }
}

fn call_with_pp_support_hir<A, F>(ppmode: &PpHirMode, tcx: TyCtxt<'_>, f: F) -> A
where
    F: FnOnce(&dyn HirPrinterSupport, hir_map::Map<'_>) -> A,
{
    match *ppmode {
        PpHirMode::Normal => {
            let annotation = NoAnn { sess: tcx.sess, tcx: Some(tcx) };
            f(&annotation, tcx.hir())
        }
        PpHirMode::Identified => {
            let annotation = IdentifiedAnnotation { sess: tcx.sess, tcx: Some(tcx) };
            f(&annotation, tcx.hir())
        }
        PpHirMode::Typed => {
            abort_on_err(tcx.analysis(()), tcx.sess);

            let annotation = TypedAnnotation { tcx, maybe_typeck_results: Cell::new(None) };
            tcx.dep_graph.with_ignore(|| f(&annotation, tcx.hir()))
        }
    }
}

trait Sess {
    /// Provides a uniform interface for re-extracting a reference to a
    /// `Session`.
    fn sess(&self) -> &Session;
}

trait AstPrinterSupport: pprust_ast::PpAnn + Sess {}
trait HirPrinterSupport: pprust_hir::PpAnn + Sess {}

struct NoAnn<'hir> {
    sess: &'hir Session,
    tcx: Option<TyCtxt<'hir>>,
}

impl<'hir> Sess for NoAnn<'hir> {
    fn sess(&self) -> &Session {
        self.sess
    }
}

impl<'tcx> AstPrinterSupport for NoAnn<'tcx> {}
impl<'hir> HirPrinterSupport for NoAnn<'hir> {}

impl<'hir> pprust_ast::PpAnn for NoAnn<'hir> {}
impl<'hir> pprust_hir::PpAnn for NoAnn<'hir> {
    fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
        if let Some(tcx) = self.tcx {
            pprust_hir::PpAnn::nested(&(&tcx.hir() as &dyn hir::intravisit::Map<'_>), state, nested)
        }
    }
}

struct IdentifiedAnnotation<'hir> {
    sess: &'hir Session,
    tcx: Option<TyCtxt<'hir>>,
}

impl<'hir> Sess for IdentifiedAnnotation<'hir> {
    fn sess(&self) -> &Session {
        self.sess
    }
}

impl<'hir> AstPrinterSupport for IdentifiedAnnotation<'hir> {}

impl<'hir> pprust_ast::PpAnn for IdentifiedAnnotation<'hir> {
    fn pre(&self, s: &mut pprust_ast::State<'_>, node: pprust_ast::AnnNode<'_>) {
        if let pprust_ast::AnnNode::Expr(_) = node {
            s.popen();
        }
    }

    fn post(&self, s: &mut pprust_ast::State<'_>, node: pprust_ast::AnnNode<'_>) {
        match node {
            pprust_ast::AnnNode::Crate(_)
            | pprust_ast::AnnNode::Ident(_)
            | pprust_ast::AnnNode::Name(_) => {}

            pprust_ast::AnnNode::Item(item) => {
                s.s.space();
                s.synth_comment(item.id.to_string())
            }
            pprust_ast::AnnNode::SubItem(id) => {
                s.s.space();
                s.synth_comment(id.to_string())
            }
            pprust_ast::AnnNode::Block(blk) => {
                s.s.space();
                s.synth_comment(format!("block {}", blk.id))
            }
            pprust_ast::AnnNode::Expr(expr) => {
                s.s.space();
                s.synth_comment(expr.id.to_string());
                s.pclose()
            }
            pprust_ast::AnnNode::Pat(pat) => {
                s.s.space();
                s.synth_comment(format!("pat {}", pat.id));
            }
        }
    }
}

impl<'hir> HirPrinterSupport for IdentifiedAnnotation<'hir> {}

impl<'hir> pprust_hir::PpAnn for IdentifiedAnnotation<'hir> {
    fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
        if let Some(ref tcx) = self.tcx {
            pprust_hir::PpAnn::nested(&(&tcx.hir() as &dyn hir::intravisit::Map<'_>), state, nested)
        }
    }

    fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
        if let pprust_hir::AnnNode::Expr(_) = node {
            s.popen();
        }
    }

    fn post(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
        match node {
            pprust_hir::AnnNode::Name(_) => {}
            pprust_hir::AnnNode::Item(item) => {
                s.s.space();
                s.synth_comment(format!("hir_id: {}", item.hir_id()));
            }
            pprust_hir::AnnNode::SubItem(id) => {
                s.s.space();
                s.synth_comment(id.to_string());
            }
            pprust_hir::AnnNode::Block(blk) => {
                s.s.space();
                s.synth_comment(format!("block hir_id: {}", blk.hir_id));
            }
            pprust_hir::AnnNode::Expr(expr) => {
                s.s.space();
                s.synth_comment(format!("expr hir_id: {}", expr.hir_id));
                s.pclose();
            }
            pprust_hir::AnnNode::Pat(pat) => {
                s.s.space();
                s.synth_comment(format!("pat hir_id: {}", pat.hir_id));
            }
            pprust_hir::AnnNode::Arm(arm) => {
                s.s.space();
                s.synth_comment(format!("arm hir_id: {}", arm.hir_id));
            }
        }
    }
}

struct HygieneAnnotation<'a> {
    sess: &'a Session,
}

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

impl<'a> AstPrinterSupport for HygieneAnnotation<'a> {}

impl<'a> pprust_ast::PpAnn for HygieneAnnotation<'a> {
    fn post(&self, s: &mut pprust_ast::State<'_>, node: pprust_ast::AnnNode<'_>) {
        match node {
            pprust_ast::AnnNode::Ident(&Ident { name, span }) => {
                s.s.space();
                s.synth_comment(format!("{}{:?}", name.as_u32(), span.ctxt()))
            }
            pprust_ast::AnnNode::Name(&name) => {
                s.s.space();
                s.synth_comment(name.as_u32().to_string())
            }
            pprust_ast::AnnNode::Crate(_) => {
                s.s.hardbreak();
                let verbose = self.sess.verbose();
                s.synth_comment(rustc_span::hygiene::debug_hygiene_data(verbose));
                s.s.hardbreak_if_not_bol();
            }
            _ => {}
        }
    }
}

struct TypedAnnotation<'tcx> {
    tcx: TyCtxt<'tcx>,
    maybe_typeck_results: Cell<Option<&'tcx ty::TypeckResults<'tcx>>>,
}

impl<'tcx> Sess for TypedAnnotation<'tcx> {
    fn sess(&self) -> &Session {
        self.tcx.sess
    }
}

impl<'tcx> HirPrinterSupport for TypedAnnotation<'tcx> {}

impl<'tcx> pprust_hir::PpAnn for TypedAnnotation<'tcx> {
    fn nested(&self, state: &mut pprust_hir::State<'_>, nested: pprust_hir::Nested) {
        let old_maybe_typeck_results = self.maybe_typeck_results.get();
        if let pprust_hir::Nested::Body(id) = nested {
            self.maybe_typeck_results.set(Some(self.tcx.typeck_body(id)));
        }
        let pp_ann = &(&self.tcx.hir() as &dyn hir::intravisit::Map<'_>);
        pprust_hir::PpAnn::nested(pp_ann, state, nested);
        self.maybe_typeck_results.set(old_maybe_typeck_results);
    }

    fn pre(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
        if let pprust_hir::AnnNode::Expr(_) = node {
            s.popen();
        }
    }

    fn post(&self, s: &mut pprust_hir::State<'_>, node: pprust_hir::AnnNode<'_>) {
        if let pprust_hir::AnnNode::Expr(expr) = node {
            let typeck_results = self.maybe_typeck_results.get().or_else(|| {
                self.tcx
                    .hir()
                    .maybe_body_owned_by(expr.hir_id.owner.def_id)
                    .map(|body_id| self.tcx.typeck_body(body_id))
            });

            if let Some(typeck_results) = typeck_results {
                s.s.space();
                s.s.word("as");
                s.s.space();
                s.s.word(typeck_results.expr_ty(expr).to_string());
            }

            s.pclose();
        }
    }
}

fn get_source(sess: &Session) -> (String, FileName) {
    let src_name = sess.io.input.source_name();
    let src = String::clone(
        sess.source_map()
            .get_source_file(&src_name)
            .expect("get_source_file")
            .src
            .as_ref()
            .expect("src"),
    );
    (src, src_name)
}

fn write_or_print(out: &str, sess: &Session) {
    sess.io.output_file.as_ref().unwrap_or(&OutFileName::Stdout).overwrite(out, sess);
}

// Extra data for pretty-printing, the form of which depends on what kind of
// pretty-printing we are doing.
pub enum PrintExtra<'tcx> {
    AfterParsing { krate: ast::Crate },
    NeedsAstMap { tcx: TyCtxt<'tcx> },
}

impl<'tcx> PrintExtra<'tcx> {
    fn with_krate<F, R>(&self, f: F) -> R
    where
        F: FnOnce(&ast::Crate) -> R
    {
        match self {
            PrintExtra::AfterParsing { krate, .. } => f(krate),
            PrintExtra::NeedsAstMap { tcx } => f(&tcx.resolver_for_lowering(()).borrow().1),
        }
    }

    fn tcx(&self) -> TyCtxt<'tcx> {
        match self {
            PrintExtra::AfterParsing { .. } => bug!("PrintExtra::tcx"),
            PrintExtra::NeedsAstMap { tcx } => *tcx,
        }
    }
}

pub fn print<'tcx>(sess: &Session, ppm: PpMode, ex: PrintExtra<'tcx>) {
    if ppm.needs_analysis() {
        abort_on_err(ex.tcx().analysis(()), sess);
    }

    let (src, src_name) = get_source(sess);

    let out = match ppm {
        Source(s) => {
            // Silently ignores an identified node.
            call_with_pp_support_ast(&s, sess, None, move |annotation| {
                debug!("pretty printing source code {:?}", s);
                let sess = annotation.sess();
                let parse = &sess.parse_sess;
                let is_expanded = ppm.needs_ast_map();
                ex.with_krate(|krate|
                    pprust_ast::print_crate(
                        sess.source_map(),
                        krate,
                        src_name,
                        src,
                        annotation,
                        is_expanded,
                        parse.edition,
                        &sess.parse_sess.attr_id_generator,
                    )
                )
            })
        }
        AstTree => {
            debug!("pretty printing AST tree");
            ex.with_krate(|krate| format!("{krate:#?}"))
        }
        AstTreeExpanded => {
            debug!("pretty-printing expanded AST");
            format!("{:#?}", ex.tcx().resolver_for_lowering(()).borrow().1)
        }
        Hir(s) => call_with_pp_support_hir(&s, ex.tcx(), move |annotation, hir_map| {
            debug!("pretty printing HIR {:?}", s);
            let sess = annotation.sess();
            let sm = sess.source_map();
            let attrs = |id| hir_map.attrs(id);
            pprust_hir::print_crate(sm, hir_map.root_module(), src_name, src, &attrs, annotation)
        }),
        HirTree => {
            debug!("pretty printing HIR tree");
            format!("{:#?}", ex.tcx().hir().krate())
        }
        Mir => {
            let mut out = Vec::new();
            write_mir_pretty(ex.tcx(), None, &mut out).unwrap();
            String::from_utf8(out).unwrap()
        }
        MirCFG => {
            let mut out = Vec::new();
            write_mir_graphviz(ex.tcx(), None, &mut out).unwrap();
            String::from_utf8(out).unwrap()
        }
        ThirTree => {
            let tcx = ex.tcx();
            let mut out = String::new();
            abort_on_err(rustc_hir_analysis::check_crate(tcx), tcx.sess);
            debug!("pretty printing THIR tree");
            for did in tcx.hir().body_owners() {
                let _ = writeln!(out, "{:?}:\n{}\n", did, tcx.thir_tree(did));
            }
            out
        }
        ThirFlat => {
            let tcx = ex.tcx();
            let mut out = String::new();
            abort_on_err(rustc_hir_analysis::check_crate(tcx), tcx.sess);
            debug!("pretty printing THIR flat");
            for did in tcx.hir().body_owners() {
                let _ = writeln!(out, "{:?}:\n{}\n", did, tcx.thir_flat(did));
            }
            out
        }
    };

    write_or_print(&out, sess);
}