Auto merge of #32156 - pnkfelix:borrowck-on-mir-move-analysis, r=nikomatsakis

Move analysis for MIR borrowck

This PR adds code for doing MIR-based gathering of the moves in a `fn` and the dataflow to determine where uninitialized locations flow to, analogous to how the same thing is done in `borrowck`.

It also adds a couple attributes to print out graphviz visualizations of the analyzed MIR that includes the dataflow analysis results.

cc @nikomatsakis

Author: bors

mk/crates.mk

@@ -97,7 +97,7 @@ DEPS_rustc := syntax fmt_macros flate arena serialize getopts rbml rustc_front\
               log graphviz rustc_llvm rustc_back rustc_data_structures\
 		  	  rustc_const_eval
 DEPS_rustc_back := std syntax rustc_llvm rustc_front flate log libc
-DEPS_rustc_borrowck := rustc rustc_front log graphviz syntax
+DEPS_rustc_borrowck := rustc rustc_front rustc_mir log graphviz syntax
 DEPS_rustc_data_structures := std log serialize
 DEPS_rustc_driver := arena flate getopts graphviz libc rustc rustc_back rustc_borrowck \
                      rustc_typeck rustc_mir rustc_resolve log syntax serialize rustc_llvm \

src/libgraphviz/lib.rs

@@ -62,15 +62,19 @@
 //!     dot::render(&edges, output).unwrap()
 //! }
 //!
-//! impl<'a> dot::Labeller<'a, Nd, Ed> for Edges {
+//! impl<'a> dot::Labeller<'a> for Edges {
+//!     type Node = Nd;
+//!     type Edge = Ed;
 //!     fn graph_id(&'a self) -> dot::Id<'a> { dot::Id::new("example1").unwrap() }
 //!
 //!     fn node_id(&'a self, n: &Nd) -> dot::Id<'a> {
 //!         dot::Id::new(format!("N{}", *n)).unwrap()
 //!     }
 //! }
 //!
-//! impl<'a> dot::GraphWalk<'a, Nd, Ed> for Edges {
+//! impl<'a> dot::GraphWalk<'a> for Edges {
+//!     type Node = Nd;
+//!     type Edge = Ed;
 //!     fn nodes(&self) -> dot::Nodes<'a,Nd> {
 //!         // (assumes that |N| \approxeq |E|)
 //!         let &Edges(ref v) = self;
@@ -167,7 +171,9 @@
 //!     dot::render(&graph, output).unwrap()
 //! }
 //!
-//! impl<'a> dot::Labeller<'a, Nd, Ed<'a>> for Graph {
+//! impl<'a> dot::Labeller<'a> for Graph {
+//!     type Node = Nd;
+//!     type Edge = Ed<'a>;
 //!     fn graph_id(&'a self) -> dot::Id<'a> { dot::Id::new("example2").unwrap() }
 //!     fn node_id(&'a self, n: &Nd) -> dot::Id<'a> {
 //!         dot::Id::new(format!("N{}", n)).unwrap()
@@ -180,7 +186,9 @@
 //!     }
 //! }
 //!
-//! impl<'a> dot::GraphWalk<'a, Nd, Ed<'a>> for Graph {
+//! impl<'a> dot::GraphWalk<'a> for Graph {
+//!     type Node = Nd;
+//!     type Edge = Ed<'a>;
 //!     fn nodes(&self) -> dot::Nodes<'a,Nd> { (0..self.nodes.len()).collect() }
 //!     fn edges(&'a self) -> dot::Edges<'a,Ed<'a>> { self.edges.iter().collect() }
 //!     fn source(&self, e: &Ed) -> Nd { let & &(s,_) = e; s }
@@ -225,7 +233,9 @@
 //!     dot::render(&graph, output).unwrap()
 //! }
 //!
-//! impl<'a> dot::Labeller<'a, Nd<'a>, Ed<'a>> for Graph {
+//! impl<'a> dot::Labeller<'a> for Graph {
+//!     type Node = Nd<'a>;
+//!     type Edge = Ed<'a>;
 //!     fn graph_id(&'a self) -> dot::Id<'a> { dot::Id::new("example3").unwrap() }
 //!     fn node_id(&'a self, n: &Nd<'a>) -> dot::Id<'a> {
 //!         dot::Id::new(format!("N{}", n.0)).unwrap()
@@ -239,7 +249,9 @@
 //!     }
 //! }
 //!
-//! impl<'a> dot::GraphWalk<'a, Nd<'a>, Ed<'a>> for Graph {
+//! impl<'a> dot::GraphWalk<'a> for Graph {
+//!     type Node = Nd<'a>;
+//!     type Edge = Ed<'a>;
 //!     fn nodes(&'a self) -> dot::Nodes<'a,Nd<'a>> {
 //!         self.nodes.iter().map(|s| &s[..]).enumerate().collect()
 //!     }
@@ -447,45 +459,48 @@ impl<'a> Id<'a> {
 /// The graph instance is responsible for providing the DOT compatible
 /// identifiers for the nodes and (optionally) rendered labels for the nodes and
 /// edges, as well as an identifier for the graph itself.
-pub trait Labeller<'a,N,E> {
+pub trait Labeller<'a> {
+    type Node;
+    type Edge;
+
     /// Must return a DOT compatible identifier naming the graph.
     fn graph_id(&'a self) -> Id<'a>;
 
     /// Maps `n` to a unique identifier with respect to `self`. The
     /// implementor is responsible for ensuring that the returned name
     /// is a valid DOT identifier.
-    fn node_id(&'a self, n: &N) -> Id<'a>;
+    fn node_id(&'a self, n: &Self::Node) -> Id<'a>;
 
     /// Maps `n` to one of the [graphviz `shape` names][1]. If `None`
     /// is returned, no `shape` attribute is specified.
     ///
     /// [1]: http://www.graphviz.org/content/node-shapes
-    fn node_shape(&'a self, _node: &N) -> Option<LabelText<'a>> {
+    fn node_shape(&'a self, _node: &Self::Node) -> Option<LabelText<'a>> {
         None
     }
 
     /// Maps `n` to a label that will be used in the rendered output.
     /// The label need not be unique, and may be the empty string; the
     /// default is just the output from `node_id`.
-    fn node_label(&'a self, n: &N) -> LabelText<'a> {
+    fn node_label(&'a self, n: &Self::Node) -> LabelText<'a> {
         LabelStr(self.node_id(n).name)
     }
 
     /// Maps `e` to a label that will be used in the rendered output.
     /// The label need not be unique, and may be the empty string; the
     /// default is in fact the empty string.
-    fn edge_label(&'a self, e: &E) -> LabelText<'a> {
+    fn edge_label(&'a self, e: &Self::Edge) -> LabelText<'a> {
         let _ignored = e;
         LabelStr("".into_cow())
     }
 
     /// Maps `n` to a style that will be used in the rendered output.
-    fn node_style(&'a self, _n: &N) -> Style {
+    fn node_style(&'a self, _n: &Self::Node) -> Style {
         Style::None
     }
 
     /// Maps `e` to a style that will be used in the rendered output.
-    fn edge_style(&'a self, _e: &E) -> Style {
+    fn edge_style(&'a self, _e: &Self::Edge) -> Style {
         Style::None
     }
 }
@@ -596,15 +611,18 @@ pub type Edges<'a,E> = Cow<'a,[E]>;
 /// `Cow<[T]>` to leave implementors the freedom to create
 /// entirely new vectors or to pass back slices into internally owned
 /// vectors.
-pub trait GraphWalk<'a, N: Clone, E: Clone> {
+pub trait GraphWalk<'a> {
+    type Node: Clone;
+    type Edge: Clone;
+
     /// Returns all the nodes in this graph.
-    fn nodes(&'a self) -> Nodes<'a, N>;
+    fn nodes(&'a self) -> Nodes<'a, Self::Node>;
     /// Returns all of the edges in this graph.
-    fn edges(&'a self) -> Edges<'a, E>;
+    fn edges(&'a self) -> Edges<'a, Self::Edge>;
     /// The source node for `edge`.
-    fn source(&'a self, edge: &E) -> N;
+    fn source(&'a self, edge: &Self::Edge) -> Self::Node;
     /// The target node for `edge`.
-    fn target(&'a self, edge: &E) -> N;
+    fn target(&'a self, edge: &Self::Edge) -> Self::Node;
 }
 
 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
@@ -622,28 +640,26 @@ pub fn default_options() -> Vec<RenderOption> {
 
 /// Renders directed graph `g` into the writer `w` in DOT syntax.
 /// (Simple wrapper around `render_opts` that passes a default set of options.)
-pub fn render<'a,
-              N: Clone + 'a,
-              E: Clone + 'a,
-              G: Labeller<'a, N, E> + GraphWalk<'a, N, E>,
-              W: Write>
-    (g: &'a G,
-     w: &mut W)
-     -> io::Result<()> {
+pub fn render<'a,N,E,G,W>(g: &'a G, w: &mut W) -> io::Result<()>
+    where N: Clone + 'a,
+          E: Clone + 'a,
+          G: Labeller<'a, Node=N, Edge=E> + GraphWalk<'a, Node=N, Edge=E>,
+          W: Write
+{
     render_opts(g, w, &[])
 }
 
 /// Renders directed graph `g` into the writer `w` in DOT syntax.
 /// (Main entry point for the library.)
-pub fn render_opts<'a,
-                   N: Clone + 'a,
-                   E: Clone + 'a,
-                   G: Labeller<'a, N, E> + GraphWalk<'a, N, E>,
-                   W: Write>
-    (g: &'a G,
-     w: &mut W,
-     options: &[RenderOption])
-     -> io::Result<()> {
+pub fn render_opts<'a, N, E, G, W>(g: &'a G,
+                                   w: &mut W,
+                                   options: &[RenderOption])
+                                   -> io::Result<()>
+    where N: Clone + 'a,
+          E: Clone + 'a,
+          G: Labeller<'a, Node=N, Edge=E> + GraphWalk<'a, Node=N, Edge=E>,
+          W: Write
+{
     fn writeln<W: Write>(w: &mut W, arg: &[&str]) -> io::Result<()> {
         for &s in arg {
             try!(w.write_all(s.as_bytes()));
@@ -858,7 +874,9 @@ mod tests {
         Id::new(format!("N{}", *n)).unwrap()
     }
 
-    impl<'a> Labeller<'a, Node, &'a Edge> for LabelledGraph {
+    impl<'a> Labeller<'a> for LabelledGraph {
+        type Node = Node;
+        type Edge = &'a Edge;
         fn graph_id(&'a self) -> Id<'a> {
             Id::new(&self.name[..]).unwrap()
         }
@@ -882,7 +900,9 @@ mod tests {
         }
     }
 
-    impl<'a> Labeller<'a, Node, &'a Edge> for LabelledGraphWithEscStrs {
+    impl<'a> Labeller<'a> for LabelledGraphWithEscStrs {
+        type Node = Node;
+        type Edge = &'a Edge;
         fn graph_id(&'a self) -> Id<'a> {
             self.graph.graph_id()
         }
@@ -901,7 +921,9 @@ mod tests {
         }
     }
 
-    impl<'a> GraphWalk<'a, Node, &'a Edge> for LabelledGraph {
+    impl<'a> GraphWalk<'a> for LabelledGraph {
+        type Node = Node;
+        type Edge = &'a Edge;
         fn nodes(&'a self) -> Nodes<'a, Node> {
             (0..self.node_labels.len()).collect()
         }
@@ -916,7 +938,9 @@ mod tests {
         }
     }
 
-    impl<'a> GraphWalk<'a, Node, &'a Edge> for LabelledGraphWithEscStrs {
+    impl<'a> GraphWalk<'a> for LabelledGraphWithEscStrs {
+        type Node = Node;
+        type Edge = &'a Edge;
         fn nodes(&'a self) -> Nodes<'a, Node> {
             self.graph.nodes()
         }

src/librustc/front/map/blocks.rs

@@ -26,7 +26,8 @@ pub use self::Code::*;
 use front::map::{self, Node};
 use syntax::abi;
 use rustc_front::hir::{Block, FnDecl};
-use syntax::ast::{Name, NodeId};
+use syntax::ast::{Attribute, Name, NodeId};
+use syntax::attr::ThinAttributesExt;
 use rustc_front::hir as ast;
 use syntax::codemap::Span;
 use rustc_front::intravisit::FnKind;
@@ -116,7 +117,8 @@ struct ItemFnParts<'a> {
     generics: &'a ast::Generics,
     body:     &'a Block,
     id:       NodeId,
-    span:     Span
+    span:     Span,
+    attrs:    &'a [Attribute],
 }
 
 /// These are all the components one can extract from a closure expr
@@ -125,12 +127,13 @@ struct ClosureParts<'a> {
     decl: &'a FnDecl,
     body: &'a Block,
     id: NodeId,
-    span: Span
+    span: Span,
+    attrs: &'a [Attribute],
 }
 
 impl<'a> ClosureParts<'a> {
-    fn new(d: &'a FnDecl, b: &'a Block, id: NodeId, s: Span) -> ClosureParts<'a> {
-        ClosureParts { decl: d, body: b, id: id, span: s }
+    fn new(d: &'a FnDecl, b: &'a Block, id: NodeId, s: Span, attrs: &'a [Attribute]) -> Self {
+        ClosureParts { decl: d, body: b, id: id, span: s, attrs: attrs }
     }
 }
 
@@ -165,37 +168,37 @@ impl<'a> FnLikeNode<'a> {
 
     pub fn body(self) -> &'a Block {
         self.handle(|i: ItemFnParts<'a>|  &*i.body,
-                    |_, _, _: &'a ast::MethodSig, _, body: &'a ast::Block, _|  body,
+                    |_, _, _: &'a ast::MethodSig, _, body: &'a ast::Block, _, _|  body,
                     |c: ClosureParts<'a>| c.body)
     }
 
     pub fn decl(self) -> &'a FnDecl {
         self.handle(|i: ItemFnParts<'a>|  &*i.decl,
-                    |_, _, sig: &'a ast::MethodSig, _, _, _|  &sig.decl,
+                    |_, _, sig: &'a ast::MethodSig, _, _, _, _|  &sig.decl,
                     |c: ClosureParts<'a>| c.decl)
     }
 
     pub fn span(self) -> Span {
         self.handle(|i: ItemFnParts|     i.span,
-                    |_, _, _: &'a ast::MethodSig, _, _, span| span,
+                    |_, _, _: &'a ast::MethodSig, _, _, span, _| span,
                     |c: ClosureParts|    c.span)
     }
 
     pub fn id(self) -> NodeId {
         self.handle(|i: ItemFnParts|     i.id,
-                    |id, _, _: &'a ast::MethodSig, _, _, _| id,
+                    |id, _, _: &'a ast::MethodSig, _, _, _, _| id,
                     |c: ClosureParts|    c.id)
     }
 
     pub fn kind(self) -> FnKind<'a> {
         let item = |p: ItemFnParts<'a>| -> FnKind<'a> {
-            FnKind::ItemFn(p.name, p.generics, p.unsafety, p.constness, p.abi, p.vis)
+            FnKind::ItemFn(p.name, p.generics, p.unsafety, p.constness, p.abi, p.vis, p.attrs)
         };
-        let closure = |_: ClosureParts| {
-            FnKind::Closure
+        let closure = |c: ClosureParts<'a>| {
+            FnKind::Closure(c.attrs)
         };
-        let method = |_, name: Name, sig: &'a ast::MethodSig, vis, _, _| {
-            FnKind::Method(name, sig, vis)
+        let method = |_, name: Name, sig: &'a ast::MethodSig, vis, _, _, attrs| {
+            FnKind::Method(name, sig, vis, attrs)
         };
         self.handle(item, method, closure)
     }
@@ -207,7 +210,8 @@ impl<'a> FnLikeNode<'a> {
                   &'a ast::MethodSig,
                   Option<ast::Visibility>,
                   &'a ast::Block,
-                  Span)
+                  Span,
+                  &'a [Attribute])
                   -> A,
         C: FnOnce(ClosureParts<'a>) -> A,
     {
@@ -224,20 +228,21 @@ impl<'a> FnLikeNode<'a> {
                         abi: abi,
                         vis: i.vis,
                         constness: constness,
-                        span: i.span
+                        span: i.span,
+                        attrs: &i.attrs,
                     }),
                 _ => panic!("item FnLikeNode that is not fn-like"),
             },
             map::NodeTraitItem(ti) => match ti.node {
                 ast::MethodTraitItem(ref sig, Some(ref body)) => {
-                    method(ti.id, ti.name, sig, None, body, ti.span)
+                    method(ti.id, ti.name, sig, None, body, ti.span, &ti.attrs)
                 }
                 _ => panic!("trait method FnLikeNode that is not fn-like"),
             },
             map::NodeImplItem(ii) => {
                 match ii.node {
                     ast::ImplItemKind::Method(ref sig, ref body) => {
-                        method(ii.id, ii.name, sig, Some(ii.vis), body, ii.span)
+                        method(ii.id, ii.name, sig, Some(ii.vis), body, ii.span, &ii.attrs)
                     }
                     _ => {
                         panic!("impl method FnLikeNode that is not fn-like")
@@ -246,7 +251,11 @@ impl<'a> FnLikeNode<'a> {
             }
             map::NodeExpr(e) => match e.node {
                 ast::ExprClosure(_, ref decl, ref block) =>
-                    closure(ClosureParts::new(&decl, &block, e.id, e.span)),
+                    closure(ClosureParts::new(&decl,
+                                              &block,
+                                              e.id,
+                                              e.span,
+                                              e.attrs.as_attr_slice())),
                 _ => panic!("expr FnLikeNode that is not fn-like"),
             },
             _ => panic!("other FnLikeNode that is not fn-like"),