Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

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

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 191 insertions, 117 deletions

diff --git a/contrib/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp b/contrib/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp
index 511e5bc..5fd6b63 100644
--- a/contrib/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp
+++ b/contrib/llvm/lib/Target/MSP430/MSP430BranchSelector.cpp
@@ -27,63 +27,84 @@ using namespace llvm;
 
 #define DEBUG_TYPE "msp430-branch-select"
 
+static cl::opt<bool>
+    BranchSelectEnabled("msp430-branch-select", cl::Hidden, cl::init(true),
+                        cl::desc("Expand out of range branches"));
+
+STATISTIC(NumSplit, "Number of machine basic blocks split");
 STATISTIC(NumExpanded, "Number of branches expanded to long format");
 
 namespace {
-  struct MSP430BSel : public MachineFunctionPass {
-    static char ID;
-    MSP430BSel() : MachineFunctionPass(ID) {}
+class MSP430BSel : public MachineFunctionPass {
 
-    /// BlockSizes - The sizes of the basic blocks in the function.
-    std::vector<unsigned> BlockSizes;
+  typedef SmallVector<int, 16> OffsetVector;
 
-    bool runOnMachineFunction(MachineFunction &Fn) override;
+  MachineFunction *MF;
+  const MSP430InstrInfo *TII;
 
-    MachineFunctionProperties getRequiredProperties() const override {
-      return MachineFunctionProperties().set(
-          MachineFunctionProperties::Property::AllVRegsAllocated);
-    }
+  unsigned measureFunction(OffsetVector &BlockOffsets,
+                           MachineBasicBlock *FromBB = nullptr);
+  bool expandBranches(OffsetVector &BlockOffsets);
 
-    const char *getPassName() const override {
-      return "MSP430 Branch Selector";
-    }
-  };
-  char MSP430BSel::ID = 0;
+public:
+  static char ID;
+  MSP430BSel() : MachineFunctionPass(ID) {}
+
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  MachineFunctionProperties getRequiredProperties() const override {
+    return MachineFunctionProperties().set(
+        MachineFunctionProperties::Property::NoVRegs);
+  }
+
+  StringRef getPassName() const override { return "MSP430 Branch Selector"; }
+};
+char MSP430BSel::ID = 0;
 }
 
-/// createMSP430BranchSelectionPass - returns an instance of the Branch
-/// Selection Pass
-///
-FunctionPass *llvm::createMSP430BranchSelectionPass() {
-  return new MSP430BSel();
+static bool isInRage(int DistanceInBytes) {
+  // According to CC430 Family User's Guide, Section 4.5.1.3, branch
+  // instructions have the signed 10-bit word offset field, so first we need to
+  // convert the distance from bytes to words, then check if it fits in 10-bit
+  // signed integer.
+  const int WordSize = 2;
+
+  assert((DistanceInBytes % WordSize == 0) &&
+         "Branch offset should be word aligned!");
+
+  int Words = DistanceInBytes / WordSize;
+  return isInt<10>(Words);
 }
 
-bool MSP430BSel::runOnMachineFunction(MachineFunction &Fn) {
-  const MSP430InstrInfo *TII =
-      static_cast<const MSP430InstrInfo *>(Fn.getSubtarget().getInstrInfo());
+/// Measure each basic block, fill the BlockOffsets, and return the size of
+/// the function, starting with BB
+unsigned MSP430BSel::measureFunction(OffsetVector &BlockOffsets,
+                                     MachineBasicBlock *FromBB) {
   // Give the blocks of the function a dense, in-order, numbering.
-  Fn.RenumberBlocks();
-  BlockSizes.resize(Fn.getNumBlockIDs());
-
-  // Measure each MBB and compute a size for the entire function.
-  unsigned FuncSize = 0;
-  for (MachineBasicBlock &MBB : Fn) {
-    unsigned BlockSize = 0;
-    for (MachineInstr &MI : MBB)
-      BlockSize += TII->GetInstSizeInBytes(MI);
-
-    BlockSizes[MBB.getNumber()] = BlockSize;
-    FuncSize += BlockSize;
+  MF->RenumberBlocks(FromBB);
+
+  MachineFunction::iterator Begin;
+  if (FromBB == nullptr) {
+    Begin = MF->begin();
+  } else {
+    Begin = FromBB->getIterator();
   }
 
-  // If the entire function is smaller than the displacement of a branch field,
-  // we know we don't need to shrink any branches in this function.  This is a
-  // common case.
-  if (FuncSize < (1 << 9)) {
-    BlockSizes.clear();
-    return false;
+  BlockOffsets.resize(MF->getNumBlockIDs());
+
+  unsigned TotalSize = BlockOffsets[Begin->getNumber()];
+  for (auto &MBB : make_range(Begin, MF->end())) {
+    BlockOffsets[MBB.getNumber()] = TotalSize;
+    for (MachineInstr &MI : MBB) {
+      TotalSize += TII->getInstSizeInBytes(MI);
+    }
   }
+  return TotalSize;
+}
 
+/// Do expand branches and split the basic blocks if necessary.
+/// Returns true if made any change.
+bool MSP430BSel::expandBranches(OffsetVector &BlockOffsets) {
   // For each conditional branch, if the offset to its destination is larger
   // than the offset field allows, transform it into a long branch sequence
   // like this:
@@ -93,91 +114,144 @@ bool MSP430BSel::runOnMachineFunction(MachineFunction &Fn) {
   //     b!CC $PC+6
   //     b MBB
   //
-  bool MadeChange = true;
-  bool EverMadeChange = false;
-  while (MadeChange) {
-    // Iteratively expand branches until we reach a fixed point.
-    MadeChange = false;
-
-    for (MachineFunction::iterator MFI = Fn.begin(), E = Fn.end(); MFI != E;
-         ++MFI) {
-      MachineBasicBlock &MBB = *MFI;
-      unsigned MBBStartOffset = 0;
-      for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end();
-           I != E; ++I) {
-        if ((I->getOpcode() != MSP430::JCC || I->getOperand(0).isImm()) &&
-            I->getOpcode() != MSP430::JMP) {
-          MBBStartOffset += TII->GetInstSizeInBytes(*I);
-          continue;
-        }
+  bool MadeChange = false;
+  for (auto MBB = MF->begin(), E = MF->end(); MBB != E; ++MBB) {
+    unsigned MBBStartOffset = 0;
+    for (auto MI = MBB->begin(), EE = MBB->end(); MI != EE; ++MI) {
+      MBBStartOffset += TII->getInstSizeInBytes(*MI);
 
-        // Determine the offset from the current branch to the destination
-        // block.
-        MachineBasicBlock *Dest = I->getOperand(0).getMBB();
-
-        int BranchSize;
-        if (Dest->getNumber() <= MBB.getNumber()) {
-          // If this is a backwards branch, the delta is the offset from the
-          // start of this block to this branch, plus the sizes of all blocks
-          // from this block to the dest.
-          BranchSize = MBBStartOffset;
-
-          for (unsigned i = Dest->getNumber(), e = MBB.getNumber(); i != e; ++i)
-            BranchSize += BlockSizes[i];
-        } else {
-          // Otherwise, add the size of the blocks between this block and the
-          // dest to the number of bytes left in this block.
-          BranchSize = -MBBStartOffset;
-
-          for (unsigned i = MBB.getNumber(), e = Dest->getNumber(); i != e; ++i)
-            BranchSize += BlockSizes[i];
-        }
+      // If this instruction is not a short branch then skip it.
+      if (MI->getOpcode() != MSP430::JCC && MI->getOpcode() != MSP430::JMP) {
+        continue;
+      }
 
-        // If this branch is in range, ignore it.
-        if (isInt<10>(BranchSize)) {
-          MBBStartOffset += 2;
-          continue;
-        }
+      MachineBasicBlock *DestBB = MI->getOperand(0).getMBB();
+      // Determine the distance from the current branch to the destination
+      // block. MBBStartOffset already includes the size of the current branch
+      // instruction.
+      int BlockDistance =
+          BlockOffsets[DestBB->getNumber()] - BlockOffsets[MBB->getNumber()];
+      int BranchDistance = BlockDistance - MBBStartOffset;
+
+      // If this branch is in range, ignore it.
+      if (isInRage(BranchDistance)) {
+        continue;
+      }
+
+      DEBUG(dbgs() << "  Found a branch that needs expanding, BB#"
+                   << DestBB->getNumber() << ", Distance " << BranchDistance
+                   << "\n");
+
+      // If JCC is not the last instruction we need to split the MBB.
+      if (MI->getOpcode() == MSP430::JCC && std::next(MI) != EE) {
+
+        DEBUG(dbgs() << "  Found a basic block that needs to be split, BB#"
+                     << MBB->getNumber() << "\n");
+
+        // Create a new basic block.
+        MachineBasicBlock *NewBB =
+            MF->CreateMachineBasicBlock(MBB->getBasicBlock());
+        MF->insert(std::next(MBB), NewBB);
 
-        // Otherwise, we have to expand it to a long branch.
-        unsigned NewSize;
-        MachineInstr &OldBranch = *I;
-        DebugLoc dl = OldBranch.getDebugLoc();
-
-        if (I->getOpcode() == MSP430::JMP) {
-          NewSize = 4;
-        } else {
-          // The BCC operands are:
-          // 0. MSP430 branch predicate
-          // 1. Target MBB
-          SmallVector<MachineOperand, 1> Cond;
-          Cond.push_back(I->getOperand(1));
-
-          // Jump over the uncond branch inst (i.e. $+6) on opposite condition.
-          TII->ReverseBranchCondition(Cond);
-          BuildMI(MBB, I, dl, TII->get(MSP430::JCC))
-            .addImm(4).addOperand(Cond[0]);
-
-          NewSize = 6;
+        // Splice the instructions following MI over to the NewBB.
+        NewBB->splice(NewBB->end(), &*MBB, std::next(MI), MBB->end());
+
+        // Update the successor lists.
+        for (MachineBasicBlock *Succ : MBB->successors()) {
+          if (Succ == DestBB) {
+            continue;
+          }
+          MBB->replaceSuccessor(Succ, NewBB);
+          NewBB->addSuccessor(Succ);
         }
-        // Uncond branch to the real destination.
-        I = BuildMI(MBB, I, dl, TII->get(MSP430::Bi)).addMBB(Dest);
 
-        // Remove the old branch from the function.
-        OldBranch.eraseFromParent();
+        // We introduced a new MBB so all following blocks should be numbered
+        // and measured again.
+        measureFunction(BlockOffsets, &*MBB);
 
-        // Remember that this instruction is NewSize bytes, increase the size of the
-        // block by NewSize-2, remember to iterate.
-        BlockSizes[MBB.getNumber()] += NewSize-2;
-        MBBStartOffset += NewSize;
+        ++NumSplit;
 
-        ++NumExpanded;
-        MadeChange = true;
+        // It may be not necessary to start all over at this point, but it's
+        // safer do this anyway.
+        return true;
       }
+
+      MachineInstr &OldBranch = *MI;
+      DebugLoc dl = OldBranch.getDebugLoc();
+      int InstrSizeDiff = -TII->getInstSizeInBytes(OldBranch);
+
+      if (MI->getOpcode() == MSP430::JCC) {
+        MachineBasicBlock *NextMBB = &*std::next(MBB);
+        assert(MBB->isSuccessor(NextMBB) &&
+               "This block must have a layout successor!");
+
+        // The BCC operands are:
+        // 0. Target MBB
+        // 1. MSP430 branch predicate
+        SmallVector<MachineOperand, 1> Cond;
+        Cond.push_back(MI->getOperand(1));
+
+        // Jump over the long branch on the opposite condition
+        TII->reverseBranchCondition(Cond);
+        MI = BuildMI(*MBB, MI, dl, TII->get(MSP430::JCC))
+                             .addMBB(NextMBB)
+                             .addOperand(Cond[0]);
+        InstrSizeDiff += TII->getInstSizeInBytes(*MI);
+        ++MI;
+      }
+
+      // Unconditional branch to the real destination.
+      MI = BuildMI(*MBB, MI, dl, TII->get(MSP430::Bi)).addMBB(DestBB);
+      InstrSizeDiff += TII->getInstSizeInBytes(*MI);
+
+      // Remove the old branch from the function.
+      OldBranch.eraseFromParent();
+
+      // The size of a new instruction is different from the old one, so we need
+      // to correct all block offsets.
+      for (int i = MBB->getNumber() + 1, e = BlockOffsets.size(); i < e; ++i) {
+        BlockOffsets[i] += InstrSizeDiff;
+      }
+      MBBStartOffset += InstrSizeDiff;
+
+      ++NumExpanded;
+      MadeChange = true;
     }
-    EverMadeChange |= MadeChange;
   }
+  return MadeChange;
+}
+
+bool MSP430BSel::runOnMachineFunction(MachineFunction &mf) {
+  MF = &mf;
+  TII = static_cast<const MSP430InstrInfo *>(MF->getSubtarget().getInstrInfo());
+
+  // If the pass is disabled, just bail early.
+  if (!BranchSelectEnabled)
+    return false;
+
+  DEBUG(dbgs() << "\n********** " << getPassName() << " **********\n");
+
+  // BlockOffsets - Contains the distance from the beginning of the function to
+  // the beginning of each basic block.
+  OffsetVector BlockOffsets;
+
+  unsigned FunctionSize = measureFunction(BlockOffsets);
+  // If the entire function is smaller than the displacement of a branch field,
+  // we know we don't need to expand any branches in this
+  // function. This is a common case.
+  if (isInRage(FunctionSize)) {
+    return false;
+  }
+
+  // Iteratively expand branches until we reach a fixed point.
+  bool MadeChange = false;
+  while (expandBranches(BlockOffsets))
+    MadeChange = true;
+
+  return MadeChange;
+}
 
-  BlockSizes.clear();
-  return true;
+/// Returns an instance of the Branch Selection Pass
+FunctionPass *llvm::createMSP430BranchSelectionPass() {
+  return new MSP430BSel();
 }