Add caching of external MIR in trans::collector

michaelwoerister · michaelwoerister · commit 9e969808e291 · 2016-01-26T10:17:54.000-05:00
diff --git a/src/librustc/mir/repr.rs b/src/librustc/mir/repr.rs
@@ -25,7 +25,7 @@ use std::{iter, u32};
 use std::ops::{Index, IndexMut};
 
 /// Lowered representation of a single function.
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Mir<'tcx> {
     /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
     /// that indexes into this vector.
@@ -146,7 +146,7 @@ pub enum BorrowKind {
 
 // A "variable" is a binding declared by the user as part of the fn
 // decl, a let, etc.
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct VarDecl<'tcx> {
     pub mutability: Mutability,
     pub name: Name,
@@ -155,7 +155,7 @@ pub struct VarDecl<'tcx> {
 
 // A "temp" is a temporary that we place on the stack. They are
 // anonymous, always mutable, and have only a type.
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct TempDecl<'tcx> {
     pub ty: Ty<'tcx>,
 }
@@ -171,7 +171,7 @@ pub struct TempDecl<'tcx> {
 //
 // there is only one argument, of type `(i32, u32)`, but two bindings
 // (`x` and `y`).
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct ArgDecl<'tcx> {
     pub ty: Ty<'tcx>,
 }
@@ -207,14 +207,14 @@ impl Debug for BasicBlock {
 ///////////////////////////////////////////////////////////////////////////
 // BasicBlock and Terminator
 
-#[derive(Debug, RustcEncodable, RustcDecodable)]
+#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct BasicBlockData<'tcx> {
     pub statements: Vec<Statement<'tcx>>,
     pub terminator: Option<Terminator<'tcx>>,
     pub is_cleanup: bool,
 }
 
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub enum Terminator<'tcx> {
     /// block should have one successor in the graph; we jump there
     Goto {
@@ -481,13 +481,13 @@ impl<'tcx> Terminator<'tcx> {
 ///////////////////////////////////////////////////////////////////////////
 // Statements
 
-#[derive(RustcEncodable, RustcDecodable)]
+#[derive(Clone, RustcEncodable, RustcDecodable)]
 pub struct Statement<'tcx> {
     pub span: Span,
     pub kind: StatementKind<'tcx>,
 }
 
-#[derive(Debug, RustcEncodable, RustcDecodable)]
+#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub enum StatementKind<'tcx> {
     Assign(Lvalue<'tcx>, Rvalue<'tcx>),
     Drop(DropKind, Lvalue<'tcx>),
diff --git a/src/librustc_trans/trans/base.rs b/src/librustc_trans/trans/base.rs
@@ -2110,6 +2110,10 @@ pub fn trans_closure<'a, 'b, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     fn record_translation_item_as_generated<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
                                                       node_id: ast::NodeId,
                                                       param_substs: &'tcx Substs<'tcx>) {
+        if !collector::collecting_debug_information(ccx) {
+            return;
+        }
+
         let def_id = match ccx.tcx().node_id_to_type(node_id).sty {
             ty::TyClosure(def_id, _) => def_id,
             _ => ccx.external_srcs()
diff --git a/src/librustc_trans/trans/collector.rs b/src/librustc_trans/trans/collector.rs
@@ -217,6 +217,7 @@ use trans::monomorphize;
 use util::nodemap::{FnvHashSet, FnvHashMap, DefIdMap};
 
 use std::hash::{Hash, Hasher};
+use std::rc::Rc;
 
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
 pub enum TransItemCollectionMode {
@@ -281,9 +282,14 @@ pub fn collect_crate_translation_items<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
         debug!("Building translation item graph, beginning at roots");
         let mut visited = FnvHashSet();
         let mut recursion_depths = DefIdMap();
+        let mut mir_cache = DefIdMap();
 
         for root in roots {
-            collect_items_rec(ccx, root, &mut visited, &mut recursion_depths);
+            collect_items_rec(ccx,
+                              root,
+                              &mut visited,
+                              &mut recursion_depths,
+                              &mut mir_cache);
         }
 
         visited
@@ -313,11 +319,27 @@ fn collect_roots<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
     roots
 }
 
+#[derive(Clone)]
+enum CachedMir<'mir, 'tcx: 'mir> {
+    Ref(&'mir mir::Mir<'tcx>),
+    Owned(Rc<mir::Mir<'tcx>>)
+}
+
+impl<'mir, 'tcx: 'mir> CachedMir<'mir, 'tcx> {
+    fn get_ref<'a>(&'a self) -> &'a mir::Mir<'tcx> {
+        match *self {
+            CachedMir::Ref(r) => r,
+            CachedMir::Owned(ref rc) => &**rc,
+        }
+    }
+}
+
 // Collect all monomorphized translation items reachable from `starting_point`
 fn collect_items_rec<'a, 'tcx: 'a>(ccx: &CrateContext<'a, 'tcx>,
                                    starting_point: TransItem<'tcx>,
                                    visited: &mut FnvHashSet<TransItem<'tcx>>,
-                                   recursion_depths: &mut DefIdMap<usize>) {
+                                   recursion_depths: &mut DefIdMap<usize>,
+                                   mir_cache: &mut DefIdMap<CachedMir<'a, 'tcx>>) {
     if !visited.insert(starting_point.clone()) {
         // We've been here already, no need to search again.
         return;
@@ -343,42 +365,21 @@ fn collect_items_rec<'a, 'tcx: 'a>(ccx: &CrateContext<'a, 'tcx>,
 
             // Scan the MIR in order to find function calls, closures, and
             // drop-glue
-            let mir_not_found_error_message = || {
-                format!("Could not find MIR for function: {}",
-                        ccx.tcx().item_path_str(def_id))
-            };
-
-            let external_mir = if !def_id.is_local() {
-                ccx.sess().cstore.maybe_get_item_mir(ccx.tcx(), def_id)
-            } else {
-                None
-            };
-
-            let mir_opt = match external_mir {
-                Some(ref mir) => Some(mir),
-                None => {
-                    let node_id = ccx.tcx().map.as_local_node_id(def_id).unwrap();
-                    ccx.mir_map().get(&node_id)
-                }
-            };
-
-            let mir = errors::expect(ccx.sess().diagnostic(),
-                                     mir_opt,
-                                     mir_not_found_error_message);
+            let mir = load_mir(ccx, def_id, mir_cache);
 
             let mut visitor = MirNeighborCollector {
                 ccx: ccx,
-                mir: mir,
+                mir: mir.get_ref(),
                 output: &mut neighbors,
                 param_substs: param_substs
             };
 
-            visitor.visit_mir(mir);
+            visitor.visit_mir(mir.get_ref());
         }
     }
 
     for neighbour in neighbors {
-        collect_items_rec(ccx, neighbour, visited, recursion_depths);
+        collect_items_rec(ccx, neighbour, visited, recursion_depths, mir_cache);
     }
 
     if let Some((def_id, depth)) = recursion_depth_reset {
@@ -388,6 +389,37 @@ fn collect_items_rec<'a, 'tcx: 'a>(ccx: &CrateContext<'a, 'tcx>,
     debug!("END collect_items_rec({})", starting_point.to_string(ccx));
 }
 
+fn load_mir<'a, 'tcx: 'a>(ccx: &CrateContext<'a, 'tcx>,
+                          def_id: DefId,
+                          mir_cache: &mut DefIdMap<CachedMir<'a, 'tcx>>)
+                          -> CachedMir<'a, 'tcx> {
+    let mir_not_found_error_message = || {
+        format!("Could not find MIR for function: {}",
+                ccx.tcx().item_path_str(def_id))
+    };
+
+    if def_id.is_local() {
+        let node_id = ccx.tcx().map.as_local_node_id(def_id).unwrap();
+        let mir_opt = ccx.mir_map().get(&node_id);
+        let mir = errors::expect(ccx.sess().diagnostic(),
+                             mir_opt,
+                             mir_not_found_error_message);
+        CachedMir::Ref(mir)
+    } else {
+        if let Some(mir) = mir_cache.get(&def_id) {
+            return mir.clone();
+        }
+
+        let mir_opt = ccx.sess().cstore.maybe_get_item_mir(ccx.tcx(), def_id);
+        let mir = errors::expect(ccx.sess().diagnostic(),
+                                 mir_opt,
+                                 mir_not_found_error_message);
+        let cached = CachedMir::Owned(Rc::new(mir));
+        mir_cache.insert(def_id, cached.clone());
+        cached
+    }
+}
+
 fn check_recursion_limit<'a, 'tcx: 'a>(ccx: &CrateContext<'a, 'tcx>,
                                        def_id: DefId,
                                        recursion_depths: &mut DefIdMap<usize>)
@@ -1488,14 +1520,15 @@ pub enum TransItemState {
     NotPredictedButGenerated,
 }
 
+pub fn collecting_debug_information(ccx: &CrateContext) -> bool {
+    return cfg!(debug_assertions) &&
+           ccx.sess().opts.debugging_opts.print_trans_items.is_some();
+}
+
 pub fn print_collection_results<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>) {
     use std::hash::{Hash, SipHasher, Hasher};
 
-    if !cfg!(debug_assertions) {
-        return;
-    }
-
-    if ccx.sess().opts.debugging_opts.print_trans_items.is_none() {
+    if !collecting_debug_information(ccx) {
         return;
     }
 
diff --git a/src/librustc_trans/trans/consts.rs b/src/librustc_trans/trans/consts.rs
@@ -30,7 +30,7 @@ use middle::def::Def;
 use middle::def_id::DefId;
 use trans::{adt, closure, debuginfo, expr, inline, machine};
 use trans::base::{self, push_ctxt};
-use trans::collector::TransItem;
+use trans::collector::{self, TransItem};
 use trans::common::{self, type_is_sized, ExprOrMethodCall, node_id_substs, C_nil, const_get_elt};
 use trans::common::{CrateContext, C_integral, C_floating, C_bool, C_str_slice, C_bytes, val_ty};
 use trans::common::{C_struct, C_undef, const_to_opt_int, const_to_opt_uint, VariantInfo, C_uint};
@@ -1018,7 +1018,9 @@ pub fn trans_static(ccx: &CrateContext,
                     attrs: &[ast::Attribute])
                     -> Result<ValueRef, ConstEvalErr> {
 
-    ccx.record_translation_item_as_generated(TransItem::Static(id));
+    if collector::collecting_debug_information(ccx) {
+        ccx.record_translation_item_as_generated(TransItem::Static(id));
+    }
 
     unsafe {
         let _icx = push_ctxt("trans_static");
diff --git a/src/librustc_trans/trans/glue.rs b/src/librustc_trans/trans/glue.rs
@@ -28,7 +28,7 @@ use trans::build::*;
 use trans::callee;
 use trans::cleanup;
 use trans::cleanup::CleanupMethods;
-use trans::collector::TransItem;
+use trans::collector::{self, TransItem};
 use trans::common::*;
 use trans::debuginfo::DebugLoc;
 use trans::declare;
@@ -498,9 +498,11 @@ fn make_drop_glue<'blk, 'tcx>(bcx: Block<'blk, 'tcx>, v0: ValueRef, g: DropGlueK
                               -> Block<'blk, 'tcx> {
     let t = g.ty();
 
-    bcx.ccx()
-       .record_translation_item_as_generated(TransItem::DropGlue(bcx.tcx()
-                                                                    .erase_regions(&t)));
+    if collector::collecting_debug_information(bcx.ccx()) {
+        bcx.ccx()
+           .record_translation_item_as_generated(TransItem::DropGlue(bcx.tcx()
+                                                                        .erase_regions(&t)));
+    }
 
     let skip_dtor = match g { DropGlueKind::Ty(_) => false, DropGlueKind::TyContents(_) => true };
     // NB: v0 is an *alias* of type t here, not a direct value.
