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, 96 insertions, 52 deletions

diff --git a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
index 33166f5..49b9754 100644
--- a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
@@ -27,6 +27,7 @@
 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
 #include "WebAssemblyMachineFunctionInfo.h"
 #include "WebAssemblySubtarget.h"
+#include "WebAssemblyUtilities.h"
 #include "llvm/ADT/PriorityQueue.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/CodeGen/MachineDominators.h"
@@ -43,9 +44,7 @@ using namespace llvm;
 
 namespace {
 class WebAssemblyCFGStackify final : public MachineFunctionPass {
-  const char *getPassName() const override {
-    return "WebAssembly CFG Stackify";
-  }
+  StringRef getPassName() const override { return "WebAssembly CFG Stackify"; }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.setPreservesCFG();
@@ -294,26 +293,16 @@ static bool ExplicitlyBranchesTo(MachineBasicBlock *Pred,
   return false;
 }
 
-/// Test whether MI is a child of some other node in an expression tree.
-static bool IsChild(const MachineInstr &MI,
-                    const WebAssemblyFunctionInfo &MFI) {
-  if (MI.getNumOperands() == 0)
-    return false;
-  const MachineOperand &MO = MI.getOperand(0);
-  if (!MO.isReg() || MO.isImplicit() || !MO.isDef())
-    return false;
-  unsigned Reg = MO.getReg();
-  return TargetRegisterInfo::isVirtualRegister(Reg) &&
-         MFI.isVRegStackified(Reg);
-}
-
 /// Insert a BLOCK marker for branches to MBB (if needed).
-static void PlaceBlockMarker(MachineBasicBlock &MBB, MachineFunction &MF,
-                             SmallVectorImpl<MachineBasicBlock *> &ScopeTops,
-                             const WebAssemblyInstrInfo &TII,
-                             const MachineLoopInfo &MLI,
-                             MachineDominatorTree &MDT,
-                             WebAssemblyFunctionInfo &MFI) {
+static void PlaceBlockMarker(
+    MachineBasicBlock &MBB, MachineFunction &MF,
+    SmallVectorImpl<MachineBasicBlock *> &ScopeTops,
+    DenseMap<const MachineInstr *, MachineInstr *> &BlockTops,
+    DenseMap<const MachineInstr *, MachineInstr *> &LoopTops,
+    const WebAssemblyInstrInfo &TII,
+    const MachineLoopInfo &MLI,
+    MachineDominatorTree &MDT,
+    WebAssemblyFunctionInfo &MFI) {
   // First compute the nearest common dominator of all forward non-fallthrough
   // predecessors so that we minimize the time that the BLOCK is on the stack,
   // which reduces overall stack height.
@@ -332,7 +321,7 @@ static void PlaceBlockMarker(MachineBasicBlock &MBB, MachineFunction &MF,
     return;
 
   assert(&MBB != &MF.front() && "Header blocks shouldn't have predecessors");
-  MachineBasicBlock *LayoutPred = &*prev(MachineFunction::iterator(&MBB));
+  MachineBasicBlock *LayoutPred = &*std::prev(MachineFunction::iterator(&MBB));
 
   // If the nearest common dominator is inside a more deeply nested context,
   // walk out to the nearest scope which isn't more deeply nested.
@@ -340,7 +329,7 @@ static void PlaceBlockMarker(MachineBasicBlock &MBB, MachineFunction &MF,
     if (MachineBasicBlock *ScopeTop = ScopeTops[I->getNumber()]) {
       if (ScopeTop->getNumber() > Header->getNumber()) {
         // Skip over an intervening scope.
-        I = next(MachineFunction::iterator(ScopeTop));
+        I = std::next(MachineFunction::iterator(ScopeTop));
       } else {
         // We found a scope level at an appropriate depth.
         Header = ScopeTop;
@@ -349,13 +338,6 @@ static void PlaceBlockMarker(MachineBasicBlock &MBB, MachineFunction &MF,
     }
   }
 
-  // If there's a loop which ends just before MBB which contains Header, we can
-  // reuse its label instead of inserting a new BLOCK.
-  for (MachineLoop *Loop = MLI.getLoopFor(LayoutPred);
-       Loop && Loop->contains(LayoutPred); Loop = Loop->getParentLoop())
-    if (Loop && LoopBottom(Loop) == LayoutPred && Loop->contains(Header))
-      return;
-
   // Decide where in Header to put the BLOCK.
   MachineBasicBlock::iterator InsertPos;
   MachineLoop *HeaderLoop = MLI.getLoopFor(Header);
@@ -363,28 +345,35 @@ static void PlaceBlockMarker(MachineBasicBlock &MBB, MachineFunction &MF,
     // Header is the header of a loop that does not lexically contain MBB, so
     // the BLOCK needs to be above the LOOP, after any END constructs.
     InsertPos = Header->begin();
-    while (InsertPos->getOpcode() != WebAssembly::LOOP)
+    while (InsertPos->getOpcode() == WebAssembly::END_BLOCK ||
+           InsertPos->getOpcode() == WebAssembly::END_LOOP)
       ++InsertPos;
   } else {
     // Otherwise, insert the BLOCK as late in Header as we can, but before the
     // beginning of the local expression tree and any nested BLOCKs.
     InsertPos = Header->getFirstTerminator();
-    while (InsertPos != Header->begin() && IsChild(*prev(InsertPos), MFI) &&
-           prev(InsertPos)->getOpcode() != WebAssembly::LOOP &&
-           prev(InsertPos)->getOpcode() != WebAssembly::END_BLOCK &&
-           prev(InsertPos)->getOpcode() != WebAssembly::END_LOOP)
+    while (InsertPos != Header->begin() &&
+           WebAssembly::isChild(*std::prev(InsertPos), MFI) &&
+           std::prev(InsertPos)->getOpcode() != WebAssembly::LOOP &&
+           std::prev(InsertPos)->getOpcode() != WebAssembly::END_BLOCK &&
+           std::prev(InsertPos)->getOpcode() != WebAssembly::END_LOOP)
       --InsertPos;
   }
 
   // Add the BLOCK.
-  BuildMI(*Header, InsertPos, DebugLoc(), TII.get(WebAssembly::BLOCK));
+  MachineInstr *Begin = BuildMI(*Header, InsertPos, DebugLoc(),
+                                TII.get(WebAssembly::BLOCK))
+      .addImm(int64_t(WebAssembly::ExprType::Void));
 
   // Mark the end of the block.
   InsertPos = MBB.begin();
   while (InsertPos != MBB.end() &&
-         InsertPos->getOpcode() == WebAssembly::END_LOOP)
+         InsertPos->getOpcode() == WebAssembly::END_LOOP &&
+         LoopTops[&*InsertPos]->getParent()->getNumber() >= Header->getNumber())
     ++InsertPos;
-  BuildMI(MBB, InsertPos, DebugLoc(), TII.get(WebAssembly::END_BLOCK));
+  MachineInstr *End = BuildMI(MBB, InsertPos, DebugLoc(),
+                              TII.get(WebAssembly::END_BLOCK));
+  BlockTops[End] = Begin;
 
   // Track the farthest-spanning scope that ends at this point.
   int Number = MBB.getNumber();
@@ -397,7 +386,7 @@ static void PlaceBlockMarker(MachineBasicBlock &MBB, MachineFunction &MF,
 static void PlaceLoopMarker(
     MachineBasicBlock &MBB, MachineFunction &MF,
     SmallVectorImpl<MachineBasicBlock *> &ScopeTops,
-    DenseMap<const MachineInstr *, const MachineBasicBlock *> &LoopTops,
+    DenseMap<const MachineInstr *, MachineInstr *> &LoopTops,
     const WebAssemblyInstrInfo &TII, const MachineLoopInfo &MLI) {
   MachineLoop *Loop = MLI.getLoopFor(&MBB);
   if (!Loop || Loop->getHeader() != &MBB)
@@ -406,13 +395,13 @@ static void PlaceLoopMarker(
   // The operand of a LOOP is the first block after the loop. If the loop is the
   // bottom of the function, insert a dummy block at the end.
   MachineBasicBlock *Bottom = LoopBottom(Loop);
-  auto Iter = next(MachineFunction::iterator(Bottom));
+  auto Iter = std::next(MachineFunction::iterator(Bottom));
   if (Iter == MF.end()) {
     MachineBasicBlock *Label = MF.CreateMachineBasicBlock();
     // Give it a fake predecessor so that AsmPrinter prints its label.
     Label->addSuccessor(Label);
     MF.push_back(Label);
-    Iter = next(MachineFunction::iterator(Bottom));
+    Iter = std::next(MachineFunction::iterator(Bottom));
   }
   MachineBasicBlock *AfterLoop = &*Iter;
 
@@ -422,12 +411,14 @@ static void PlaceLoopMarker(
   while (InsertPos != MBB.end() &&
          InsertPos->getOpcode() == WebAssembly::END_LOOP)
     ++InsertPos;
-  BuildMI(MBB, InsertPos, DebugLoc(), TII.get(WebAssembly::LOOP));
+  MachineInstr *Begin = BuildMI(MBB, InsertPos, DebugLoc(),
+                                TII.get(WebAssembly::LOOP))
+      .addImm(int64_t(WebAssembly::ExprType::Void));
 
   // Mark the end of the loop.
   MachineInstr *End = BuildMI(*AfterLoop, AfterLoop->begin(), DebugLoc(),
                               TII.get(WebAssembly::END_LOOP));
-  LoopTops[End] = &MBB;
+  LoopTops[End] = Begin;
 
   assert((!ScopeTops[AfterLoop->getNumber()] ||
           ScopeTops[AfterLoop->getNumber()]->getNumber() < MBB.getNumber()) &&
@@ -449,6 +440,54 @@ GetDepth(const SmallVectorImpl<const MachineBasicBlock *> &Stack,
   return Depth;
 }
 
+/// In normal assembly languages, when the end of a function is unreachable,
+/// because the function ends in an infinite loop or a noreturn call or similar,
+/// it isn't necessary to worry about the function return type at the end of
+/// the function, because it's never reached. However, in WebAssembly, blocks
+/// that end at the function end need to have a return type signature that
+/// matches the function signature, even though it's unreachable. This function
+/// checks for such cases and fixes up the signatures.
+static void FixEndsAtEndOfFunction(
+    MachineFunction &MF,
+    const WebAssemblyFunctionInfo &MFI,
+    DenseMap<const MachineInstr *, MachineInstr *> &BlockTops,
+    DenseMap<const MachineInstr *, MachineInstr *> &LoopTops) {
+  assert(MFI.getResults().size() <= 1);
+
+  if (MFI.getResults().empty())
+    return;
+
+  WebAssembly::ExprType retType;
+  switch (MFI.getResults().front().SimpleTy) {
+  case MVT::i32: retType = WebAssembly::ExprType::I32; break;
+  case MVT::i64: retType = WebAssembly::ExprType::I64; break;
+  case MVT::f32: retType = WebAssembly::ExprType::F32; break;
+  case MVT::f64: retType = WebAssembly::ExprType::F64; break;
+  case MVT::v16i8: retType = WebAssembly::ExprType::I8x16; break;
+  case MVT::v8i16: retType = WebAssembly::ExprType::I16x8; break;
+  case MVT::v4i32: retType = WebAssembly::ExprType::I32x4; break;
+  case MVT::v4f32: retType = WebAssembly::ExprType::F32x4; break;
+  default: llvm_unreachable("unexpected return type");
+  }
+
+  for (MachineBasicBlock &MBB : reverse(MF)) {
+    for (MachineInstr &MI : reverse(MBB)) {
+      if (MI.isPosition() || MI.isDebugValue())
+        continue;
+      if (MI.getOpcode() == WebAssembly::END_BLOCK) {
+        BlockTops[&MI]->getOperand(0).setImm(int32_t(retType));
+        continue;
+      }
+      if (MI.getOpcode() == WebAssembly::END_LOOP) {
+        LoopTops[&MI]->getOperand(0).setImm(int32_t(retType));
+        continue;
+      }
+      // Something other than an `end`. We're done.
+      return;
+    }
+  }
+}
+
 /// Insert LOOP and BLOCK markers at appropriate places.
 static void PlaceMarkers(MachineFunction &MF, const MachineLoopInfo &MLI,
                          const WebAssemblyInstrInfo &TII,
@@ -461,15 +500,18 @@ static void PlaceMarkers(MachineFunction &MF, const MachineLoopInfo &MLI,
   // we may insert at the end.
   SmallVector<MachineBasicBlock *, 8> ScopeTops(MF.getNumBlockIDs() + 1);
 
-  // For eacn LOOP_END, the corresponding LOOP.
-  DenseMap<const MachineInstr *, const MachineBasicBlock *> LoopTops;
+  // For each LOOP_END, the corresponding LOOP.
+  DenseMap<const MachineInstr *, MachineInstr *> LoopTops;
+
+  // For each END_BLOCK, the corresponding BLOCK.
+  DenseMap<const MachineInstr *, MachineInstr *> BlockTops;
 
   for (auto &MBB : MF) {
     // Place the LOOP for MBB if MBB is the header of a loop.
     PlaceLoopMarker(MBB, MF, ScopeTops, LoopTops, TII, MLI);
 
     // Place the BLOCK for MBB if MBB is branched to from above.
-    PlaceBlockMarker(MBB, MF, ScopeTops, TII, MLI, MDT, MFI);
+    PlaceBlockMarker(MBB, MF, ScopeTops, BlockTops, LoopTops, TII, MLI, MDT, MFI);
   }
 
   // Now rewrite references to basic blocks to be depth immediates.
@@ -478,21 +520,19 @@ static void PlaceMarkers(MachineFunction &MF, const MachineLoopInfo &MLI,
     for (auto &MI : reverse(MBB)) {
       switch (MI.getOpcode()) {
       case WebAssembly::BLOCK:
-        assert(ScopeTops[Stack.back()->getNumber()] == &MBB &&
+        assert(ScopeTops[Stack.back()->getNumber()]->getNumber() <= MBB.getNumber() &&
                "Block should be balanced");
         Stack.pop_back();
         break;
       case WebAssembly::LOOP:
         assert(Stack.back() == &MBB && "Loop top should be balanced");
         Stack.pop_back();
-        Stack.pop_back();
         break;
       case WebAssembly::END_BLOCK:
         Stack.push_back(&MBB);
         break;
       case WebAssembly::END_LOOP:
-        Stack.push_back(&MBB);
-        Stack.push_back(LoopTops[&MI]);
+        Stack.push_back(LoopTops[&MI]->getParent());
         break;
       default:
         if (MI.isTerminator()) {
@@ -511,6 +551,10 @@ static void PlaceMarkers(MachineFunction &MF, const MachineLoopInfo &MLI,
     }
   }
   assert(Stack.empty() && "Control flow should be balanced");
+
+  // Fix up block/loop signatures at the end of the function to conform to
+  // WebAssembly's rules.
+  FixEndsAtEndOfFunction(MF, MFI, BlockTops, LoopTops);
 }
 
 bool WebAssemblyCFGStackify::runOnMachineFunction(MachineFunction &MF) {
@@ -520,7 +564,7 @@ bool WebAssemblyCFGStackify::runOnMachineFunction(MachineFunction &MF) {
 
   const auto &MLI = getAnalysis<MachineLoopInfo>();
   auto &MDT = getAnalysis<MachineDominatorTree>();
-  // Liveness is not tracked for EXPR_STACK physreg.
+  // Liveness is not tracked for VALUE_STACK physreg.
   const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
   WebAssemblyFunctionInfo &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
   MF.getRegInfo().invalidateLiveness();