Update llvm/clang to trunk r126547.

There are several bugfixes in this update, but the most important one is
to ensure __start_ and __stop_ symbols for linker sets and kernel module
metadata are always emitted in object files:

  http://llvm.org/bugs/show_bug.cgi?id=9292

Before this fix, if you compiled kernel modules with clang, they would
not be properly processed by kldxref, and if they had any dependencies,
the kernel would fail to load those.  Another problem occurred when
attempting to mount a tmpfs filesystem, which would result in 'operation
not supported by device'.

1 files changed, 16 insertions, 2 deletions

diff --git a/contrib/llvm/lib/CodeGen/SplitKit.cpp b/contrib/llvm/lib/CodeGen/SplitKit.cpp
index 5663936..fd5d50b 100644
--- a/contrib/llvm/lib/CodeGen/SplitKit.cpp
+++ b/contrib/llvm/lib/CodeGen/SplitKit.cpp
@@ -167,6 +167,20 @@ void SplitAnalysis::calcLiveBlockInfo() {
   }
 }
 
+bool SplitAnalysis::isOriginalEndpoint(SlotIndex Idx) const {
+  unsigned OrigReg = VRM.getOriginal(CurLI->reg);
+  const LiveInterval &Orig = LIS.getInterval(OrigReg);
+  assert(!Orig.empty() && "Splitting empty interval?");
+  LiveInterval::const_iterator I = Orig.find(Idx);
+
+  // Range containing Idx should begin at Idx.
+  if (I != Orig.end() && I->start <= Idx)
+    return I->start == Idx;
+
+  // Range does not contain Idx, previous must end at Idx.
+  return I != Orig.begin() && (--I)->end == Idx;
+}
+
 void SplitAnalysis::print(const BlockPtrSet &B, raw_ostream &OS) const {
   for (BlockPtrSet::const_iterator I = B.begin(), E = B.end(); I != E; ++I) {
     unsigned count = UsingBlocks.lookup(*I);
@@ -947,10 +961,10 @@ void SplitEditor::splitSingleBlocks(const SplitAnalysis::BlockPtrSet &Blocks) {
 
     openIntv();
     SlotIndex SegStart = enterIntvBefore(BI.FirstUse);
-    if (BI.LastUse < BI.LastSplitPoint) {
+    if (!BI.LiveOut || BI.LastUse < BI.LastSplitPoint) {
       useIntv(SegStart, leaveIntvAfter(BI.LastUse));
     } else {
-      // THe last use os after tha last valid split point.
+      // The last use is after the last valid split point.
       SlotIndex SegStop = leaveIntvBefore(BI.LastSplitPoint);
       useIntv(SegStart, SegStop);
       overlapIntv(SegStop, BI.LastUse);