Auto merge of #31916 - nagisa:mir-passmgr-2, r=arielb1

Add Pass manager for MIR

A new PR, since rebasing the original one (#31448) properly was a pain. Since then there has been several changes most notable of which:

1. Removed the pretty-printing with `#[rustc_mir(graphviz/pretty)]`, mostly because we now have `--unpretty=mir`, IMHO that’s the direction we should expand this functionality into;
2. Reverted the infercx change done for typeck, because typeck can make an infercx for itself by being a `MirMapPass`

r? @nikomatsakis

Author: bors

src/librustc/dep_graph/mod.rs

@@ -10,6 +10,7 @@
 
 use self::thread::{DepGraphThreadData, DepMessage};
 use middle::def_id::DefId;
+use syntax::ast::NodeId;
 use middle::ty::TyCtxt;
 use rustc_front::hir;
 use rustc_front::intravisit::Visitor;
@@ -71,6 +72,7 @@ pub enum DepNode {
     IntrinsicCheck(DefId),
     MatchCheck(DefId),
     MirMapConstruction(DefId),
+    MirTypeck(NodeId),
     BorrowCheck(DefId),
     RvalueCheck(DefId),
     Reachability,

src/librustc/mir/mir_map.rs

@@ -8,31 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-use dep_graph::DepNode;
 use util::nodemap::NodeMap;
 use mir::repr::Mir;
-use mir::transform::MirPass;
-use middle::ty::{self, TyCtxt};
-use middle::infer;
 
 pub struct MirMap<'tcx> {
     pub map: NodeMap<Mir<'tcx>>,
 }
-
-impl<'tcx> MirMap<'tcx> {
-    pub fn run_passes(&mut self, passes: &mut [Box<MirPass>], tcx: &TyCtxt<'tcx>) {
-        if passes.is_empty() { return; }
-
-        for (&id, mir) in &mut self.map {
-            let did = tcx.map.local_def_id(id);
-            let _task = tcx.dep_graph.in_task(DepNode::MirMapConstruction(did));
-
-            let param_env = ty::ParameterEnvironment::for_item(tcx, id);
-            let infcx = infer::new_infer_ctxt(tcx, &tcx.tables, Some(param_env));
-
-            for pass in &mut *passes {
-                pass.run_on_mir(mir, &infcx)
-            }
-        }
-    }
-}

src/librustc/mir/repr.rs

@@ -207,7 +207,7 @@ impl Debug for BasicBlock {
 }
 
 ///////////////////////////////////////////////////////////////////////////
-// BasicBlock and Terminator
+// BasicBlockData and Terminator
 
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct BasicBlockData<'tcx> {

src/librustc/mir/transform.rs

@@ -8,9 +8,68 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use mir::mir_map::MirMap;
 use mir::repr::Mir;
-use middle::infer::InferCtxt;
+use middle::ty::TyCtxt;
+use syntax::ast::NodeId;
 
-pub trait MirPass {
-    fn run_on_mir<'a, 'tcx>(&mut self, mir: &mut Mir<'tcx>, infcx: &InferCtxt<'a, 'tcx>);
+/// Various information about pass.
+pub trait Pass {
+    // fn name() for printouts of various sorts?
+    // fn should_run(Session) to check if pass should run?
+}
+
+/// A pass which inspects the whole MirMap.
+pub trait MirMapPass<'tcx>: Pass {
+    fn run_pass(&mut self, cx: &TyCtxt<'tcx>, map: &mut MirMap<'tcx>);
+}
+
+/// A pass which inspects Mir of functions in isolation.
+pub trait MirPass<'tcx>: Pass {
+    fn run_pass(&mut self, cx: &TyCtxt<'tcx>, id: NodeId, mir: &mut Mir<'tcx>);
+}
+
+impl<'tcx, T: MirPass<'tcx>> MirMapPass<'tcx> for T {
+    fn run_pass(&mut self, tcx: &TyCtxt<'tcx>, map: &mut MirMap<'tcx>) {
+        for (&id, mir) in &mut map.map {
+            MirPass::run_pass(self, tcx, id, mir);
+        }
+    }
+}
+
+/// A manager for MIR passes.
+pub struct Passes {
+    passes: Vec<Box<for<'tcx> MirMapPass<'tcx>>>,
+    plugin_passes: Vec<Box<for<'tcx> MirMapPass<'tcx>>>
+}
+
+impl Passes {
+    pub fn new() -> Passes {
+        let passes = Passes {
+            passes: Vec::new(),
+            plugin_passes: Vec::new()
+        };
+        passes
+    }
+
+    pub fn run_passes<'tcx>(&mut self, pcx: &TyCtxt<'tcx>, map: &mut MirMap<'tcx>) {
+        for pass in &mut self.plugin_passes {
+            pass.run_pass(pcx, map);
+        }
+        for pass in &mut self.passes {
+            pass.run_pass(pcx, map);
+        }
+    }
+
+    /// Pushes a built-in pass.
+    pub fn push_pass(&mut self, pass: Box<for<'a> MirMapPass<'a>>) {
+        self.passes.push(pass);
+    }
+}
+
+/// Copies the plugin passes.
+impl ::std::iter::Extend<Box<for<'a> MirMapPass<'a>>> for Passes {
+    fn extend<I: IntoIterator<Item=Box<for <'a> MirMapPass<'a>>>>(&mut self, it: I) {
+        self.plugin_passes.extend(it);
+    }
 }

src/librustc/session/mod.rs

@@ -13,7 +13,7 @@ use middle::cstore::CrateStore;
 use middle::dependency_format;
 use session::search_paths::PathKind;
 use util::nodemap::{NodeMap, FnvHashMap};
-use mir::transform::MirPass;
+use mir::transform as mir_pass;
 
 use syntax::ast::{NodeId, NodeIdAssigner, Name};
 use syntax::codemap::{Span, MultiSpan};
@@ -60,7 +60,7 @@ pub struct Session {
     pub lint_store: RefCell<lint::LintStore>,
     pub lints: RefCell<NodeMap<Vec<(lint::LintId, Span, String)>>>,
     pub plugin_llvm_passes: RefCell<Vec<String>>,
-    pub plugin_mir_passes: RefCell<Vec<Box<MirPass>>>,
+    pub mir_passes: RefCell<mir_pass::Passes>,
     pub plugin_attributes: RefCell<Vec<(String, AttributeType)>>,
     pub crate_types: RefCell<Vec<config::CrateType>>,
     pub dependency_formats: RefCell<dependency_format::Dependencies>,
@@ -477,7 +477,7 @@ pub fn build_session_(sopts: config::Options,
         lint_store: RefCell::new(lint::LintStore::new()),
         lints: RefCell::new(NodeMap()),
         plugin_llvm_passes: RefCell::new(Vec::new()),
-        plugin_mir_passes: RefCell::new(Vec::new()),
+        mir_passes: RefCell::new(mir_pass::Passes::new()),
         plugin_attributes: RefCell::new(Vec::new()),
         crate_types: RefCell::new(Vec::new()),
         dependency_formats: RefCell::new(FnvHashMap()),

src/librustc_driver/driver.rs

@@ -568,7 +568,7 @@ pub fn phase_2_configure_and_expand(sess: &Session,
         }
 
         *sess.plugin_llvm_passes.borrow_mut() = llvm_passes;
-        *sess.plugin_mir_passes.borrow_mut() = mir_passes;
+        sess.mir_passes.borrow_mut().extend(mir_passes);
         *sess.plugin_attributes.borrow_mut() = attributes.clone();
     }));
 
@@ -865,9 +865,19 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
                  "MIR dump",
                  || mir::mir_map::build_mir_for_crate(tcx));
 
-        time(time_passes,
-             "MIR passes",
-             || mir_map.run_passes(&mut sess.plugin_mir_passes.borrow_mut(), tcx));
+        time(time_passes, "MIR passes", || {
+            let mut passes = sess.mir_passes.borrow_mut();
+            // Push all the built-in passes.
+            passes.push_pass(box mir::transform::remove_dead_blocks::RemoveDeadBlocks);
+            passes.push_pass(box mir::transform::type_check::TypeckMir);
+            passes.push_pass(box mir::transform::simplify_cfg::SimplifyCfg);
+            // Late passes
+            passes.push_pass(box mir::transform::no_landing_pads::NoLandingPads);
+            passes.push_pass(box mir::transform::remove_dead_blocks::RemoveDeadBlocks);
+            passes.push_pass(box mir::transform::erase_regions::EraseRegions);
+            // And run everything.
+            passes.run_passes(tcx, &mut mir_map);
+        });
 
         time(time_passes,
              "borrow checking",
@@ -916,9 +926,8 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
 }
 
 /// Run the translation phase to LLVM, after which the AST and analysis can
-/// be discarded.
 pub fn phase_4_translate_to_llvm<'tcx>(tcx: &TyCtxt<'tcx>,
-                                       mut mir_map: MirMap<'tcx>,
+                                       mir_map: MirMap<'tcx>,
                                        analysis: ty::CrateAnalysis)
                                        -> trans::CrateTranslation {
     let time_passes = tcx.sess.time_passes();
@@ -927,10 +936,6 @@ pub fn phase_4_translate_to_llvm<'tcx>(tcx: &TyCtxt<'tcx>,
          "resolving dependency formats",
          || dependency_format::calculate(&tcx.sess));
 
-    time(time_passes,
-         "erasing regions from MIR",
-         || mir::transform::erase_regions::erase_regions(tcx, &mut mir_map));
-
     // Option dance to work around the lack of stack once closures.
     time(time_passes,
          "translation",

src/librustc_driver/pretty.rs

@@ -31,6 +31,7 @@ use rustc_resolve as resolve;
 use rustc_metadata::cstore::CStore;
 
 use rustc_mir::pretty::write_mir_pretty;
+use rustc_mir::graphviz::write_mir_graphviz;
 
 use syntax::ast::{self, BlockCheckMode};
 use syntax::codemap;
@@ -44,6 +45,7 @@ use graphviz as dot;
 
 use std::fs::File;
 use std::io::{self, Write};
+use std::iter;
 use std::option;
 use std::path::PathBuf;
 use std::str::FromStr;
@@ -80,6 +82,7 @@ pub enum PpMode {
     PpmHir(PpSourceMode),
     PpmFlowGraph(PpFlowGraphMode),
     PpmMir,
+    PpmMirCFG,
 }
 
 pub fn parse_pretty(sess: &Session,
@@ -100,6 +103,7 @@ pub fn parse_pretty(sess: &Session,
         ("hir,identified", true) => PpmHir(PpmIdentified),
         ("hir,typed", true) => PpmHir(PpmTyped),
         ("mir", true) => PpmMir,
+        ("mir-cfg", true) => PpmMirCFG,
         ("flowgraph", true) => PpmFlowGraph(PpFlowGraphMode::Default),
         ("flowgraph,unlabelled", true) => PpmFlowGraph(PpFlowGraphMode::UnlabelledEdges),
         _ => {
@@ -574,6 +578,7 @@ fn needs_ast_map(ppm: &PpMode, opt_uii: &Option<UserIdentifiedItem>) -> bool {
         PpmSource(PpmExpandedHygiene) |
         PpmHir(_) |
         PpmMir |
+        PpmMirCFG |
         PpmFlowGraph(_) => true,
         PpmSource(PpmTyped) => panic!("invalid state"),
     }
@@ -590,6 +595,7 @@ fn needs_expansion(ppm: &PpMode) -> bool {
         PpmSource(PpmExpandedHygiene) |
         PpmHir(_) |
         PpmMir |
+        PpmMirCFG |
         PpmFlowGraph(_) => true,
         PpmSource(PpmTyped) => panic!("invalid state"),
     }
@@ -807,9 +813,15 @@ pub fn pretty_print_input(sess: Session,
             })
         }
 
-        (PpmMir, None) => {
-            debug!("pretty printing MIR for whole crate");
-            let ast_map = ast_map.expect("--unpretty mir missing ast_map");
+        (pp_type@PpmMir, uii) | (pp_type@PpmMirCFG, uii) => {
+            let ast_map = ast_map.expect("--unpretty missing ast_map");
+            let nodeid = if let Some(uii) = uii {
+                debug!("pretty printing MIR for {:?}", uii);
+                Some(uii.to_one_node_id("--unpretty", &sess, &ast_map))
+            } else {
+                debug!("pretty printing MIR for whole crate");
+                None
+            };
             abort_on_err(driver::phase_3_run_analysis_passes(&sess,
                                                              &cstore,
                                                              ast_map,
@@ -818,38 +830,25 @@ pub fn pretty_print_input(sess: Session,
                                                              resolve::MakeGlobMap::No,
                                                              |tcx, mir_map, _, _| {
                 if let Some(mir_map) = mir_map {
-                    for (nodeid, mir) in &mir_map.map {
-                        try!(writeln!(out, "MIR for {}", tcx.map.node_to_string(*nodeid)));
-                        try!(write_mir_pretty(mir, &mut out));
+                    if let Some(nodeid) = nodeid {
+                        let mir = mir_map.map.get(&nodeid).unwrap_or_else(|| {
+                            sess.fatal(&format!("no MIR map entry for node {}", nodeid))
+                        });
+                        try!(match pp_type {
+                            PpmMir => write_mir_pretty(tcx, iter::once((&nodeid, mir)), &mut out),
+                            _ => write_mir_graphviz(tcx, iter::once((&nodeid, mir)), &mut out)
+                        });
+                    } else {
+                        try!(match pp_type {
+                            PpmMir => write_mir_pretty(tcx, mir_map.map.iter(), &mut out),
+                            _ => write_mir_graphviz(tcx, mir_map.map.iter(), &mut out)
+                        });
                     }
                 }
                 Ok(())
             }), &sess)
         }
 
-        (PpmMir, Some(uii)) => {
-            debug!("pretty printing MIR for {:?}", uii);
-            let ast_map = ast_map.expect("--unpretty mir missing ast_map");
-            let nodeid = uii.to_one_node_id("--unpretty", &sess, &ast_map);
-
-            abort_on_err(driver::phase_3_run_analysis_passes(&sess,
-                                                             &cstore,
-                                                             ast_map,
-                                                             &arenas,
-                                                             &id,
-                                                             resolve::MakeGlobMap::No,
-                                                             |tcx, mir_map, _, _| {
-                if let Some(mir_map) = mir_map {
-                    try!(writeln!(out, "MIR for {}", tcx.map.node_to_string(nodeid)));
-                    let mir = mir_map.map.get(&nodeid).unwrap_or_else(|| {
-                        sess.fatal(&format!("no MIR map entry for node {}", nodeid))
-                    });
-                    try!(write_mir_pretty(mir, &mut out));
-                }
-                Ok(())
-            }), &sess)
-        }
-
         (PpmFlowGraph(mode), opt_uii) => {
             debug!("pretty printing flow graph for {:?}", opt_uii);
             let uii = opt_uii.unwrap_or_else(|| {

src/librustc_mir/graphviz.rs

@@ -13,30 +13,34 @@ use rustc::mir::repr::*;
 use rustc::middle::ty;
 use std::fmt::Debug;
 use std::io::{self, Write};
+use syntax::ast::NodeId;
 
-/// Write a graphviz DOT graph for the given MIR.
-pub fn write_mir_graphviz<W: Write>(mir: &Mir, w: &mut W) -> io::Result<()> {
-    try!(writeln!(w, "digraph Mir {{"));
+/// Write a graphviz DOT graph of a list of MIRs.
+pub fn write_mir_graphviz<'a, 't, W, I>(tcx: &ty::TyCtxt<'t>, iter: I, w: &mut W) -> io::Result<()>
+where W: Write, I: Iterator<Item=(&'a NodeId, &'a Mir<'a>)> {
+    for (&nodeid, mir) in iter {
+        try!(writeln!(w, "digraph Mir_{} {{", nodeid));
 
-    // Global graph properties
-    try!(writeln!(w, r#"    graph [fontname="monospace"];"#));
-    try!(writeln!(w, r#"    node [fontname="monospace"];"#));
-    try!(writeln!(w, r#"    edge [fontname="monospace"];"#));
+        // Global graph properties
+        try!(writeln!(w, r#"    graph [fontname="monospace"];"#));
+        try!(writeln!(w, r#"    node [fontname="monospace"];"#));
+        try!(writeln!(w, r#"    edge [fontname="monospace"];"#));
 
-    // Graph label
-    try!(write_graph_label(mir, w));
+        // Graph label
+        try!(write_graph_label(tcx, nodeid, mir, w));
 
-    // Nodes
-    for block in mir.all_basic_blocks() {
-        try!(write_node(block, mir, w));
-    }
+        // Nodes
+        for block in mir.all_basic_blocks() {
+            try!(write_node(block, mir, w));
+        }
 
-    // Edges
-    for source in mir.all_basic_blocks() {
-        try!(write_edges(source, mir, w));
+        // Edges
+        for source in mir.all_basic_blocks() {
+            try!(write_edges(source, mir, w));
+        }
+        try!(writeln!(w, "}}"))
     }
-
-    writeln!(w, "}}")
+    Ok(())
 }
 
 /// Write a graphviz DOT node for the given basic block.
@@ -84,8 +88,9 @@ fn write_edges<W: Write>(source: BasicBlock, mir: &Mir, w: &mut W) -> io::Result
 /// Write the graphviz DOT label for the overall graph. This is essentially a block of text that
 /// will appear below the graph, showing the type of the `fn` this MIR represents and the types of
 /// all the variables and temporaries.
-fn write_graph_label<W: Write>(mir: &Mir, w: &mut W) -> io::Result<()> {
-    try!(write!(w, "    label=<fn("));
+fn write_graph_label<W: Write>(tcx: &ty::TyCtxt, nid: NodeId, mir: &Mir, w: &mut W)
+-> io::Result<()> {
+    try!(write!(w, "    label=<fn {}(", dot::escape_html(&tcx.map.path_to_string(nid))));
 
     // fn argument types.
     for (i, arg) in mir.arg_decls.iter().enumerate() {