---

yaml
---
r: 276799
b: refs/heads/try
c: 6a3b558
h: refs/heads/master
i:
  276797: 8ab4868
  276795: 1ca5ea9
  276791: bd7021b
  276783: 2631ef8
  276767: dd40690
  276735: c449fb3

Author: bors

[refs]

@@ -1,7 +1,7 @@
 ---
 refs/heads/master: 6dbb0e86aec11050480beb76eade6fb805010ba7
 refs/heads/snap-stage3: 235d77457d80b549dad3ac36d94f235208a1eafb
-refs/heads/try: 913a2b4b0525c75ecf915076c4fd1e16187f8b51
+refs/heads/try: 6a3b5585061e34bc87374adec993a6b1f0ec2a55
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try/configure

@@ -608,6 +608,7 @@ opt inject-std-version 1 "inject the current compiler version of libstd into pro
 opt llvm-version-check 1 "check if the LLVM version is supported, build anyway"
 opt rustbuild 0 "use the rust and cargo based build system"
 opt orbit 0 "get MIR where it belongs - everywhere; most importantly, in orbit"
+opt codegen-tests 1 "run the src/test/codegen tests"
 
 # Optimization and debugging options. These may be overridden by the release channel, etc.
 opt_nosave optimize 1 "build optimized rust code"
@@ -1497,7 +1498,9 @@ do
         LLVM_INST_DIR=$CFG_LLVM_ROOT
         do_reconfigure=0
         # Check that LLVm FileCheck is available. Needed for the tests
-        need_cmd $LLVM_INST_DIR/bin/FileCheck
+        if [ -z "$CFG_DISABLE_CODEGEN_TESTS" ]; then
+            need_cmd $LLVM_INST_DIR/bin/FileCheck
+        fi
     fi
 
     if [ ${do_reconfigure} -ne 0 ]

branches/try/mk/tests.mk

@@ -305,11 +305,15 @@ check-stage$(1)-T-$(2)-H-$(3)-exec: \
 	check-stage$(1)-T-$(2)-H-$(3)-doc-crates-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-debuginfo-gdb-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-debuginfo-lldb-exec \
-	check-stage$(1)-T-$(2)-H-$(3)-codegen-exec \
-	check-stage$(1)-T-$(2)-H-$(3)-codegen-units-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-doc-exec \
 	check-stage$(1)-T-$(2)-H-$(3)-pretty-exec
 
+ifndef CFG_DISABLE_CODEGEN_TESTS
+check-stage$(1)-T-$(2)-H-$(3)-exec: \
+	check-stage$(1)-T-$(2)-H-$(3)-codegen-exec \
+	check-stage$(1)-T-$(2)-H-$(3)-codegen-units-exec
+endif
+
 # Only test the compiler-dependent crates when the target is
 # able to build a compiler (when the target triple is in the set of host triples)
 ifneq ($$(findstring $(2),$$(CFG_HOST)),)

branches/try/src/libcore/num/dec2flt/mod.rs

@@ -154,8 +154,8 @@ from_str_float_impl!(f64);
 /// for [`f32`] and [`f64`].
 ///
 /// [`FromStr`]: ../str/trait.FromStr.html
-/// [`f32`]: ../primitive.f32.html
-/// [`f64`]: ../primitive.f64.html
+/// [`f32`]: ../../std/primitive.f32.html
+/// [`f64`]: ../../std/primitive.f64.html
 #[derive(Debug, Clone, PartialEq)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct ParseFloatError {

branches/try/src/librustc_data_structures/bitvec.rs

@@ -8,7 +8,10 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use std::iter::FromIterator;
+
 /// A very simple BitVector type.
+#[derive(Clone)]
 pub struct BitVector {
     data: Vec<u64>,
 }
@@ -50,7 +53,9 @@ impl BitVector {
     pub fn grow(&mut self, num_bits: usize) {
         let num_words = u64s(num_bits);
         let extra_words = self.data.len() - num_words;
-        self.data.extend((0..extra_words).map(|_| 0));
+        if extra_words > 0 {
+            self.data.extend((0..extra_words).map(|_| 0));
+        }
     }
 
     /// Iterates over indexes of set bits in a sorted order
@@ -93,6 +98,27 @@ impl<'a> Iterator for BitVectorIter<'a> {
     }
 }
 
+impl FromIterator<bool> for BitVector {
+    fn from_iter<I>(iter: I) -> BitVector where I: IntoIterator<Item=bool> {
+        let iter = iter.into_iter();
+        let (len, _) = iter.size_hint();
+        // Make the minimum length for the bitvector 64 bits since that's
+        // the smallest non-zero size anyway.
+        let len = if len < 64 { 64 } else { len };
+        let mut bv = BitVector::new(len);
+        for (idx, val) in iter.enumerate() {
+            if idx > len {
+                bv.grow(idx);
+            }
+            if val {
+                bv.insert(idx);
+            }
+        }
+
+        bv
+    }
+}
+
 /// A "bit matrix" is basically a square matrix of booleans
 /// represented as one gigantic bitvector. In other words, it is as if
 /// you have N bitvectors, each of length N. Note that `elements` here is `N`/

branches/try/src/librustc_driver/driver.rs

@@ -881,10 +881,7 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(sess: &'tcx Session,
             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);
         });
@@ -937,16 +934,25 @@ 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
 pub fn phase_4_translate_to_llvm<'tcx>(tcx: &TyCtxt<'tcx>,
-                                       mir_map: MirMap<'tcx>,
-                                       analysis: ty::CrateAnalysis)
-                                       -> trans::CrateTranslation {
+                                       mut mir_map: MirMap<'tcx>,
+                                       analysis: ty::CrateAnalysis) -> trans::CrateTranslation {
     let time_passes = tcx.sess.time_passes();
 
     time(time_passes,
          "resolving dependency formats",
          || dependency_format::calculate(&tcx.sess));
 
-    // Option dance to work around the lack of stack once closures.
+    // Run the passes that transform the MIR into a more suitable for translation
+    // to LLVM code.
+    time(time_passes, "Prepare MIR codegen passes", || {
+        let mut passes = ::rustc::mir::transform::Passes::new();
+        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);
+        passes.push_pass(box mir::transform::break_critical_edges::BreakCriticalEdges);
+        passes.run_passes(tcx, &mut mir_map);
+    });
+
     time(time_passes,
          "translation",
          move || trans::trans_crate(tcx, &mir_map, analysis))

branches/try/src/librustc_mir/lib.rs

@@ -42,3 +42,4 @@ mod hair;
 pub mod mir_map;
 pub mod pretty;
 pub mod transform;
+pub mod traversal;

branches/try/src/librustc_mir/transform/break_critical_edges.rs

@@ -0,0 +1,117 @@
+// Copyright 2016 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.
+
+use rustc::ty::TyCtxt;
+use rustc::mir::repr::*;
+use rustc::mir::transform::{MirPass, Pass};
+use syntax::ast::NodeId;
+
+use rustc_data_structures::bitvec::BitVector;
+
+use traversal;
+
+pub struct BreakCriticalEdges;
+
+/**
+ * Breaks critical edges in the MIR.
+ *
+ * Critical edges are edges that are neither the only edge leaving a
+ * block, nor the only edge entering one.
+ *
+ * When you want something to happen "along" an edge, you can either
+ * do at the end of the predecessor block, or at the start of the
+ * successor block. Critical edges have to be broken in order to prevent
+ * "edge actions" from affecting other edges.
+ *
+ * This function will break those edges by inserting new blocks along them.
+ *
+ * A special case is Drop and Call terminators with unwind/cleanup successors,
+ * They use `invoke` in LLVM, which terminates a block, meaning that code cannot
+ * be inserted after them, so even if an edge is the only edge leaving a block
+ * like that, we still insert blocks if the edge is one of many entering the
+ * target.
+ *
+ * NOTE: Simplify CFG will happily undo most of the work this pass does.
+ *
+ */
+
+impl<'tcx> MirPass<'tcx> for BreakCriticalEdges {
+    fn run_pass(&mut self, _: &TyCtxt<'tcx>, _: NodeId, mir: &mut Mir<'tcx>) {
+        break_critical_edges(mir);
+    }
+}
+
+impl Pass for BreakCriticalEdges {}
+
+fn break_critical_edges(mir: &mut Mir) {
+    let mut pred_count = vec![0u32; mir.basic_blocks.len()];
+
+    // Build the precedecessor map for the MIR
+    for (_, data) in traversal::preorder(mir) {
+        if let Some(ref term) = data.terminator {
+            for &tgt in term.successors().iter() {
+                pred_count[tgt.index()] += 1;
+            }
+        }
+    }
+
+    let cleanup_map : BitVector = mir.basic_blocks
+        .iter().map(|bb| bb.is_cleanup).collect();
+
+    // We need a place to store the new blocks generated
+    let mut new_blocks = Vec::new();
+
+    let bbs = mir.all_basic_blocks();
+    let cur_len = mir.basic_blocks.len();
+
+    for &bb in &bbs {
+        let data = mir.basic_block_data_mut(bb);
+
+        if let Some(ref mut term) = data.terminator {
+            let is_invoke = term_is_invoke(term);
+            let term_span = term.span;
+            let term_scope = term.scope;
+            let succs = term.successors_mut();
+            if succs.len() > 1 || (succs.len() > 0 && is_invoke) {
+                for tgt in succs {
+                    let num_preds = pred_count[tgt.index()];
+                    if num_preds > 1 {
+                        // It's a critical edge, break it
+                        let goto = Terminator {
+                            span: term_span,
+                            scope: term_scope,
+                            kind: TerminatorKind::Goto { target: *tgt }
+                        };
+                        let mut data = BasicBlockData::new(Some(goto));
+                        data.is_cleanup = cleanup_map.contains(tgt.index());
+
+                        // Get the index it will be when inserted into the MIR
+                        let idx = cur_len + new_blocks.len();
+                        new_blocks.push(data);
+                        *tgt = BasicBlock::new(idx);
+                    }
+                }
+            }
+        }
+    }
+
+    debug!("Broke {} N edges", new_blocks.len());
+
+    mir.basic_blocks.extend_from_slice(&new_blocks);
+}
+
+// Returns true if the terminator would use an invoke in LLVM.
+fn term_is_invoke(term: &Terminator) -> bool {
+    match term.kind {
+        TerminatorKind::Call { cleanup: Some(_), .. } |
+        TerminatorKind::Drop { unwind: Some(_), .. } => true,
+        _ => false
+    }
+}

branches/try/src/librustc_mir/transform/mod.rs

@@ -13,3 +13,4 @@ pub mod simplify_cfg;
 pub mod erase_regions;
 pub mod no_landing_pads;
 pub mod type_check;
+pub mod break_critical_edges;