MFC r309124:

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0.  Also completely revamp the build system for
clang, llvm, lldb and their related tools.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes:	yes

MFC r309147:

Pull in r282174 from upstream llvm trunk (by Krzysztof Parzyszek):

  [PPC] Set SP after loading data from stack frame, if no red zone is
  present

  Follow-up to r280705: Make sure that the SP is only restored after
  all data is loaded from the stack frame, if there is no red zone.

  This completes the fix for
  https://llvm.org/bugs/show_bug.cgi?id=26519.

  Differential Revision: https://reviews.llvm.org/D24466

Reported by:    Mark Millard
PR:             214433

MFC r309149:

Pull in r283060 from upstream llvm trunk (by Hal Finkel):

  [PowerPC] Refactor soft-float support, and enable PPC64 soft float

  This change enables soft-float for PowerPC64, and also makes
  soft-float disable all vector instruction sets for both 32-bit and
  64-bit modes. This latter part is necessary because the PPC backend
  canonicalizes many Altivec vector types to floating-point types, and
  so soft-float breaks scalarization support for many operations. Both
  for embedded targets and for operating-system kernels desiring
  soft-float support, it seems reasonable that disabling hardware
  floating-point also disables vector instructions (embedded targets
  without hardware floating point support are unlikely to have Altivec,
  etc. and operating system kernels desiring not to use floating-point
  registers to lower syscall cost are unlikely to want to use vector
  registers either). If someone needs this to work, we'll need to
  change the fact that we promote many Altivec operations to act on
  v4f32. To make it possible to disable Altivec when soft-float is
  enabled, hardware floating-point support needs to be expressed as a
  positive feature, like the others, and not a negative feature,
  because target features cannot have dependencies on the disabling of
  some other feature. So +soft-float has now become -hard-float.

  Fixes PR26970.

Pull in r283061 from upstream clang trunk (by Hal Finkel):

  [PowerPC] Enable soft-float for PPC64, and +soft-float -> -hard-float

  Enable soft-float support on PPC64, as the backend now supports it.
  Also, the backend now uses -hard-float instead of +soft-float, so set
  the target features accordingly.

  Fixes PR26970.

Reported by:	Mark Millard
PR:		214433

MFC r309212:

Add a few missed clang 3.9.0 files to OptionalObsoleteFiles.

MFC r309262:

Fix packaging for clang, lldb and lld 3.9.0

During the upgrade of clang/llvm etc to 3.9.0 in r309124, the PACKAGE
directive in the usr.bin/clang/*.mk files got dropped accidentally.

Restore it, with a few minor changes and additions:
* Correct license in clang.ucl to NCSA
* Add PACKAGE=clang for clang and most of the "ll" tools
* Put lldb in its own package
* Put lld in its own package

Reviewed by:	gjb, jmallett
Differential Revision: https://reviews.freebsd.org/D8666

MFC r309656:

During the bootstrap phase, when building the minimal llvm library on
PowerPC, add lib/Support/Atomic.cpp.  This is needed because upstream
llvm revision r271821 disabled the use of std::call_once, which causes
some fallback functions from Atomic.cpp to be used instead.

Reported by:	Mark Millard
PR:		214902

MFC r309835:

Tentatively apply https://reviews.llvm.org/D18730 to work around gcc PR
70528 (bogus error: constructor required before non-static data member).
This should fix buildworld with the external gcc package.

Reported by:	https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc/

MFC r310194:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
3.9.1 release.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/3.9.1/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/lld/docs/ReleaseNotes.html>

Relnotes:	yes

1 files changed, 38 insertions, 53 deletions

diff --git a/contrib/llvm/lib/CodeGen/SpillPlacement.cpp b/contrib/llvm/lib/CodeGen/SpillPlacement.cpp
index d30cfc2..f10c98e 100644
--- a/contrib/llvm/lib/CodeGen/SpillPlacement.cpp
+++ b/contrib/llvm/lib/CodeGen/SpillPlacement.cpp
@@ -173,6 +173,17 @@ struct SpillPlacement::Node {
       Value = 0;
     return Before != preferReg();
   }
+
+  void getDissentingNeighbors(SparseSet<unsigned> &List,
+                              const Node nodes[]) const {
+    for (const auto &Elt : Links) {
+      unsigned n = Elt.second;
+      // Neighbors that already have the same value are not going to
+      // change because of this node changing.
+      if (Value != nodes[n].Value)
+        List.insert(n);
+    }
+  }
 };
 
 bool SpillPlacement::runOnMachineFunction(MachineFunction &mf) {
@@ -182,6 +193,8 @@ bool SpillPlacement::runOnMachineFunction(MachineFunction &mf) {
 
   assert(!nodes && "Leaking node array");
   nodes = new Node[bundles->getNumBundles()];
+  TodoList.clear();
+  TodoList.setUniverse(bundles->getNumBundles());
 
   // Compute total ingoing and outgoing block frequencies for all bundles.
   BlockFrequencies.resize(mf.getNumBlockIDs());
@@ -199,10 +212,12 @@ bool SpillPlacement::runOnMachineFunction(MachineFunction &mf) {
 void SpillPlacement::releaseMemory() {
   delete[] nodes;
   nodes = nullptr;
+  TodoList.clear();
 }
 
 /// activate - mark node n as active if it wasn't already.
 void SpillPlacement::activate(unsigned n) {
+  TodoList.insert(n);
   if (ActiveNodes->test(n))
     return;
   ActiveNodes->set(n);
@@ -287,10 +302,6 @@ void SpillPlacement::addLinks(ArrayRef<unsigned> Links) {
       continue;
     activate(ib);
     activate(ob);
-    if (nodes[ib].Links.empty() && !nodes[ib].mustSpill())
-      Linked.push_back(ib);
-    if (nodes[ob].Links.empty() && !nodes[ob].mustSpill())
-      Linked.push_back(ob);
     BlockFrequency Freq = BlockFrequencies[Number];
     nodes[ib].addLink(ob, Freq);
     nodes[ob].addLink(ib, Freq);
@@ -298,76 +309,50 @@ void SpillPlacement::addLinks(ArrayRef<unsigned> Links) {
 }
 
 bool SpillPlacement::scanActiveBundles() {
-  Linked.clear();
   RecentPositive.clear();
   for (int n = ActiveNodes->find_first(); n>=0; n = ActiveNodes->find_next(n)) {
-    nodes[n].update(nodes, Threshold);
+    update(n);
     // A node that must spill, or a node without any links is not going to
     // change its value ever again, so exclude it from iterations.
     if (nodes[n].mustSpill())
       continue;
-    if (!nodes[n].Links.empty())
-      Linked.push_back(n);
     if (nodes[n].preferReg())
       RecentPositive.push_back(n);
   }
   return !RecentPositive.empty();
 }
 
+bool SpillPlacement::update(unsigned n) {
+  if (!nodes[n].update(nodes, Threshold))
+    return false;
+  nodes[n].getDissentingNeighbors(TodoList, nodes);
+  return true;
+}
+
 /// iterate - Repeatedly update the Hopfield nodes until stability or the
 /// maximum number of iterations is reached.
-/// @param Linked - Numbers of linked nodes that need updating.
 void SpillPlacement::iterate() {
-  // First update the recently positive nodes. They have likely received new
-  // negative bias that will turn them off.
-  while (!RecentPositive.empty())
-    nodes[RecentPositive.pop_back_val()].update(nodes, Threshold);
-
-  if (Linked.empty())
-    return;
+  // We do not need to push those node in the todolist.
+  // They are already been proceeded as part of the previous iteration.
+  RecentPositive.clear();
 
-  // Run up to 10 iterations. The edge bundle numbering is closely related to
-  // basic block numbering, so there is a strong tendency towards chains of
-  // linked nodes with sequential numbers. By scanning the linked nodes
-  // backwards and forwards, we make it very likely that a single node can
-  // affect the entire network in a single iteration. That means very fast
-  // convergence, usually in a single iteration.
-  for (unsigned iteration = 0; iteration != 10; ++iteration) {
-    // Scan backwards, skipping the last node when iteration is not zero. When
-    // iteration is not zero, the last node was just updated.
-    bool Changed = false;
-    for (SmallVectorImpl<unsigned>::const_reverse_iterator I =
-           iteration == 0 ? Linked.rbegin() : std::next(Linked.rbegin()),
-           E = Linked.rend(); I != E; ++I) {
-      unsigned n = *I;
-      if (nodes[n].update(nodes, Threshold)) {
-        Changed = true;
-        if (nodes[n].preferReg())
-          RecentPositive.push_back(n);
-      }
-    }
-    if (!Changed || !RecentPositive.empty())
-      return;
-
-    // Scan forwards, skipping the first node which was just updated.
-    Changed = false;
-    for (SmallVectorImpl<unsigned>::const_iterator I =
-           std::next(Linked.begin()), E = Linked.end(); I != E; ++I) {
-      unsigned n = *I;
-      if (nodes[n].update(nodes, Threshold)) {
-        Changed = true;
-        if (nodes[n].preferReg())
-          RecentPositive.push_back(n);
-      }
-    }
-    if (!Changed || !RecentPositive.empty())
-      return;
+  // Since the last iteration, the todolist have been augmented by calls
+  // to addConstraints, addLinks, and co.
+  // Update the network energy starting at this new frontier.
+  // The call to ::update will add the nodes that changed into the todolist.
+  unsigned Limit = bundles->getNumBundles() * 10;
+  while(Limit-- > 0 && !TodoList.empty()) {
+    unsigned n = TodoList.pop_back_val();
+    if (!update(n))
+      continue;
+    if (nodes[n].preferReg())
+      RecentPositive.push_back(n);
   }
 }
 
 void SpillPlacement::prepare(BitVector &RegBundles) {
-  Linked.clear();
   RecentPositive.clear();
+  TodoList.clear();
   // Reuse RegBundles as our ActiveNodes vector.
   ActiveNodes = &RegBundles;
   ActiveNodes->clear();