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, 119 insertions, 30 deletions

diff --git a/contrib/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/contrib/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 43d5c3c..c8d0579 100644
--- a/contrib/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/contrib/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -63,6 +63,21 @@ const unsigned MaxNumPhiBBsValueReachabilityCheck = 20;
 // depth otherwise the algorithm in aliasGEP will assert.
 static const unsigned MaxLookupSearchDepth = 6;
 
+bool BasicAAResult::invalidate(Function &F, const PreservedAnalyses &PA,
+                               FunctionAnalysisManager::Invalidator &Inv) {
+  // We don't care if this analysis itself is preserved, it has no state. But
+  // we need to check that the analyses it depends on have been. Note that we
+  // may be created without handles to some analyses and in that case don't
+  // depend on them.
+  if (Inv.invalidate<AssumptionAnalysis>(F, PA) ||
+      (DT && Inv.invalidate<DominatorTreeAnalysis>(F, PA)) ||
+      (LI && Inv.invalidate<LoopAnalysis>(F, PA)))
+    return true;
+
+  // Otherwise this analysis result remains valid.
+  return false;
+}
+
 //===----------------------------------------------------------------------===//
 // Useful predicates
 //===----------------------------------------------------------------------===//
@@ -227,7 +242,7 @@ static bool isObjectSize(const Value *V, uint64_t Size, const DataLayout &DL,
           Offset = 0;
           return V;
         }
-      // FALL THROUGH.
+        LLVM_FALLTHROUGH;
       case Instruction::Add:
         V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
                                 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
@@ -275,7 +290,7 @@ static bool isObjectSize(const Value *V, uint64_t Size, const DataLayout &DL,
         GetLinearExpression(CastOp, Scale, Offset, ZExtBits, SExtBits, DL,
                             Depth + 1, AC, DT, NSW, NUW);
 
-    // zext(zext(%x)) == zext(%x), and similiarly for sext; we'll handle this
+    // zext(zext(%x)) == zext(%x), and similarly for sext; we'll handle this
     // by just incrementing the number of bits we've extended by.
     unsigned ExtendedBy = NewWidth - SmallWidth;
 
@@ -409,11 +424,13 @@ bool BasicAAResult::DecomposeGEPExpression(const Value *V,
     // Walk the indices of the GEP, accumulating them into BaseOff/VarIndices.
     gep_type_iterator GTI = gep_type_begin(GEPOp);
     unsigned PointerSize = DL.getPointerSizeInBits(AS);
+    // Assume all GEP operands are constants until proven otherwise.
+    bool GepHasConstantOffset = true;
     for (User::const_op_iterator I = GEPOp->op_begin() + 1, E = GEPOp->op_end();
-         I != E; ++I) {
+         I != E; ++I, ++GTI) {
       const Value *Index = *I;
       // Compute the (potentially symbolic) offset in bytes for this index.
-      if (StructType *STy = dyn_cast<StructType>(*GTI++)) {
+      if (StructType *STy = GTI.getStructTypeOrNull()) {
         // For a struct, add the member offset.
         unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
         if (FieldNo == 0)
@@ -429,11 +446,13 @@ bool BasicAAResult::DecomposeGEPExpression(const Value *V,
         if (CIdx->isZero())
           continue;
         Decomposed.OtherOffset +=
-          DL.getTypeAllocSize(*GTI) * CIdx->getSExtValue();
+          DL.getTypeAllocSize(GTI.getIndexedType()) * CIdx->getSExtValue();
         continue;
       }
 
-      uint64_t Scale = DL.getTypeAllocSize(*GTI);
+      GepHasConstantOffset = false;
+
+      uint64_t Scale = DL.getTypeAllocSize(GTI.getIndexedType());
       unsigned ZExtBits = 0, SExtBits = 0;
 
       // If the integer type is smaller than the pointer size, it is implicitly
@@ -458,7 +477,7 @@ bool BasicAAResult::DecomposeGEPExpression(const Value *V,
       //   A[x][x] -> x*16 + x*4 -> x*20
       // This also ensures that 'x' only appears in the index list once.
       for (unsigned i = 0, e = Decomposed.VarIndices.size(); i != e; ++i) {
-        if (Decomposed.VarIndices[i].V == Index && 
+        if (Decomposed.VarIndices[i].V == Index &&
             Decomposed.VarIndices[i].ZExtBits == ZExtBits &&
             Decomposed.VarIndices[i].SExtBits == SExtBits) {
           Scale += Decomposed.VarIndices[i].Scale;
@@ -479,10 +498,12 @@ bool BasicAAResult::DecomposeGEPExpression(const Value *V,
     }
 
     // Take care of wrap-arounds
-    Decomposed.StructOffset =
-      adjustToPointerSize(Decomposed.StructOffset, PointerSize);
-    Decomposed.OtherOffset =
-      adjustToPointerSize(Decomposed.OtherOffset, PointerSize);
+    if (GepHasConstantOffset) {
+      Decomposed.StructOffset =
+          adjustToPointerSize(Decomposed.StructOffset, PointerSize);
+      Decomposed.OtherOffset =
+          adjustToPointerSize(Decomposed.OtherOffset, PointerSize);
+    }
 
     // Analyze the base pointer next.
     V = GEPOp->getOperand(0);
@@ -603,6 +624,10 @@ FunctionModRefBehavior BasicAAResult::getModRefBehavior(const Function *F) {
 
   if (F->onlyAccessesArgMemory())
     Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesArgumentPointees);
+  else if (F->onlyAccessesInaccessibleMemory())
+    Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleMem);
+  else if (F->onlyAccessesInaccessibleMemOrArgMem())
+    Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleOrArgMem);
 
   return Min;
 }
@@ -732,7 +757,8 @@ ModRefInfo BasicAAResult::getModRefInfo(ImmutableCallSite CS,
       // pointer were passed to arguments that were neither of these, then it
       // couldn't be no-capture.
       if (!(*CI)->getType()->isPointerTy() ||
-          (!CS.doesNotCapture(OperandNo) && !CS.isByValArgument(OperandNo)))
+          (!CS.doesNotCapture(OperandNo) &&
+           OperandNo < CS.getNumArgOperands() && !CS.isByValArgument(OperandNo)))
         continue;
 
       // If this is a no-capture pointer argument, see if we can tell that it
@@ -765,6 +791,31 @@ ModRefInfo BasicAAResult::getModRefInfo(ImmutableCallSite CS,
       return MRI_NoModRef;
   }
 
+  // The semantics of memcpy intrinsics forbid overlap between their respective
+  // operands, i.e., source and destination of any given memcpy must no-alias.
+  // If Loc must-aliases either one of these two locations, then it necessarily
+  // no-aliases the other.
+  if (auto *Inst = dyn_cast<MemCpyInst>(CS.getInstruction())) {
+    AliasResult SrcAA, DestAA;
+
+    if ((SrcAA = getBestAAResults().alias(MemoryLocation::getForSource(Inst),
+                                          Loc)) == MustAlias)
+      // Loc is exactly the memcpy source thus disjoint from memcpy dest.
+      return MRI_Ref;
+    if ((DestAA = getBestAAResults().alias(MemoryLocation::getForDest(Inst),
+                                           Loc)) == MustAlias)
+      // The converse case.
+      return MRI_Mod;
+
+    // It's also possible for Loc to alias both src and dest, or neither.
+    ModRefInfo rv = MRI_NoModRef;
+    if (SrcAA != NoAlias)
+      rv = static_cast<ModRefInfo>(rv | MRI_Ref);
+    if (DestAA != NoAlias)
+      rv = static_cast<ModRefInfo>(rv | MRI_Mod);
+    return rv;
+  }
+
   // While the assume intrinsic is marked as arbitrarily writing so that
   // proper control dependencies will be maintained, it never aliases any
   // particular memory location.
@@ -781,6 +832,32 @@ ModRefInfo BasicAAResult::getModRefInfo(ImmutableCallSite CS,
   if (isIntrinsicCall(CS, Intrinsic::experimental_guard))
     return MRI_Ref;
 
+  // Like assumes, invariant.start intrinsics were also marked as arbitrarily
+  // writing so that proper control dependencies are maintained but they never
+  // mod any particular memory location visible to the IR.
+  // *Unlike* assumes (which are now modeled as NoModRef), invariant.start
+  // intrinsic is now modeled as reading memory. This prevents hoisting the
+  // invariant.start intrinsic over stores. Consider:
+  // *ptr = 40;
+  // *ptr = 50;
+  // invariant_start(ptr)
+  // int val = *ptr;
+  // print(val);
+  //
+  // This cannot be transformed to:
+  //
+  // *ptr = 40;
+  // invariant_start(ptr)
+  // *ptr = 50;
+  // int val = *ptr;
+  // print(val);
+  //
+  // The transformation will cause the second store to be ignored (based on
+  // rules of invariant.start)  and print 40, while the first program always
+  // prints 50.
+  if (isIntrinsicCall(CS, Intrinsic::invariant_start))
+    return MRI_Ref;
+
   // The AAResultBase base class has some smarts, lets use them.
   return AAResultBase::getModRefInfo(CS, Loc);
 }
@@ -1114,13 +1191,14 @@ AliasResult BasicAAResult::aliasGEP(const GEPOperator *GEP1, uint64_t V1Size,
       return MayAlias;
 
     AliasResult R = aliasCheck(UnderlyingV1, MemoryLocation::UnknownSize,
-                               AAMDNodes(), V2, V2Size, V2AAInfo);
+                               AAMDNodes(), V2, MemoryLocation::UnknownSize,
+                               V2AAInfo, nullptr, UnderlyingV2);
     if (R != MustAlias)
       // If V2 may alias GEP base pointer, conservatively returns MayAlias.
       // If V2 is known not to alias GEP base pointer, then the two values
-      // cannot alias per GEP semantics: "A pointer value formed from a
-      // getelementptr instruction is associated with the addresses associated
-      // with the first operand of the getelementptr".
+      // cannot alias per GEP semantics: "Any memory access must be done through
+      // a pointer value associated with an address range of the memory access,
+      // otherwise the behavior is undefined.".
       return R;
 
     // If the max search depth is reached the result is undefined
@@ -1251,7 +1329,8 @@ static AliasResult MergeAliasResults(AliasResult A, AliasResult B) {
 AliasResult BasicAAResult::aliasSelect(const SelectInst *SI, uint64_t SISize,
                                        const AAMDNodes &SIAAInfo,
                                        const Value *V2, uint64_t V2Size,
-                                       const AAMDNodes &V2AAInfo) {
+                                       const AAMDNodes &V2AAInfo,
+                                       const Value *UnderV2) {
   // If the values are Selects with the same condition, we can do a more precise
   // check: just check for aliases between the values on corresponding arms.
   if (const SelectInst *SI2 = dyn_cast<SelectInst>(V2))
@@ -1269,12 +1348,14 @@ AliasResult BasicAAResult::aliasSelect(const SelectInst *SI, uint64_t SISize,
   // If both arms of the Select node NoAlias or MustAlias V2, then returns
   // NoAlias / MustAlias. Otherwise, returns MayAlias.
   AliasResult Alias =
-      aliasCheck(V2, V2Size, V2AAInfo, SI->getTrueValue(), SISize, SIAAInfo);
+      aliasCheck(V2, V2Size, V2AAInfo, SI->getTrueValue(),
+                 SISize, SIAAInfo, UnderV2);
   if (Alias == MayAlias)
     return MayAlias;
 
   AliasResult ThisAlias =
-      aliasCheck(V2, V2Size, V2AAInfo, SI->getFalseValue(), SISize, SIAAInfo);
+      aliasCheck(V2, V2Size, V2AAInfo, SI->getFalseValue(), SISize, SIAAInfo,
+                 UnderV2);
   return MergeAliasResults(ThisAlias, Alias);
 }
 
@@ -1282,8 +1363,8 @@ AliasResult BasicAAResult::aliasSelect(const SelectInst *SI, uint64_t SISize,
 /// another.
 AliasResult BasicAAResult::aliasPHI(const PHINode *PN, uint64_t PNSize,
                                     const AAMDNodes &PNAAInfo, const Value *V2,
-                                    uint64_t V2Size,
-                                    const AAMDNodes &V2AAInfo) {
+                                    uint64_t V2Size, const AAMDNodes &V2AAInfo,
+                                    const Value *UnderV2) {
   // Track phi nodes we have visited. We use this information when we determine
   // value equivalence.
   VisitedPhiBBs.insert(PN->getParent());
@@ -1362,7 +1443,8 @@ AliasResult BasicAAResult::aliasPHI(const PHINode *PN, uint64_t PNSize,
     PNSize = MemoryLocation::UnknownSize;
 
   AliasResult Alias =
-      aliasCheck(V2, V2Size, V2AAInfo, V1Srcs[0], PNSize, PNAAInfo);
+      aliasCheck(V2, V2Size, V2AAInfo, V1Srcs[0],
+                 PNSize, PNAAInfo, UnderV2);
 
   // Early exit if the check of the first PHI source against V2 is MayAlias.
   // Other results are not possible.
@@ -1375,7 +1457,7 @@ AliasResult BasicAAResult::aliasPHI(const PHINode *PN, uint64_t PNSize,
     Value *V = V1Srcs[i];
 
     AliasResult ThisAlias =
-        aliasCheck(V2, V2Size, V2AAInfo, V, PNSize, PNAAInfo);
+        aliasCheck(V2, V2Size, V2AAInfo, V, PNSize, PNAAInfo, UnderV2);
     Alias = MergeAliasResults(ThisAlias, Alias);
     if (Alias == MayAlias)
       break;
@@ -1388,7 +1470,8 @@ AliasResult BasicAAResult::aliasPHI(const PHINode *PN, uint64_t PNSize,
 /// array references.
 AliasResult BasicAAResult::aliasCheck(const Value *V1, uint64_t V1Size,
                                       AAMDNodes V1AAInfo, const Value *V2,
-                                      uint64_t V2Size, AAMDNodes V2AAInfo) {
+                                      uint64_t V2Size, AAMDNodes V2AAInfo, 
+                                      const Value *O1, const Value *O2) {
   // If either of the memory references is empty, it doesn't matter what the
   // pointer values are.
   if (V1Size == 0 || V2Size == 0)
@@ -1416,8 +1499,11 @@ AliasResult BasicAAResult::aliasCheck(const Value *V1, uint64_t V1Size,
     return NoAlias; // Scalars cannot alias each other
 
   // Figure out what objects these things are pointing to if we can.
-  const Value *O1 = GetUnderlyingObject(V1, DL, MaxLookupSearchDepth);
-  const Value *O2 = GetUnderlyingObject(V2, DL, MaxLookupSearchDepth);
+  if (O1 == nullptr)
+    O1 = GetUnderlyingObject(V1, DL, MaxLookupSearchDepth);
+
+  if (O2 == nullptr)
+    O2 = GetUnderlyingObject(V2, DL, MaxLookupSearchDepth);
 
   // Null values in the default address space don't point to any object, so they
   // don't alias any other pointer.
@@ -1500,23 +1586,26 @@ AliasResult BasicAAResult::aliasCheck(const Value *V1, uint64_t V1Size,
 
   if (isa<PHINode>(V2) && !isa<PHINode>(V1)) {
     std::swap(V1, V2);
+    std::swap(O1, O2);
     std::swap(V1Size, V2Size);
     std::swap(V1AAInfo, V2AAInfo);
   }
   if (const PHINode *PN = dyn_cast<PHINode>(V1)) {
-    AliasResult Result = aliasPHI(PN, V1Size, V1AAInfo, V2, V2Size, V2AAInfo);
+    AliasResult Result = aliasPHI(PN, V1Size, V1AAInfo,
+                                  V2, V2Size, V2AAInfo, O2);
     if (Result != MayAlias)
       return AliasCache[Locs] = Result;
   }
 
   if (isa<SelectInst>(V2) && !isa<SelectInst>(V1)) {
     std::swap(V1, V2);
+    std::swap(O1, O2);
     std::swap(V1Size, V2Size);
     std::swap(V1AAInfo, V2AAInfo);
   }
   if (const SelectInst *S1 = dyn_cast<SelectInst>(V1)) {
     AliasResult Result =
-        aliasSelect(S1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo);
+        aliasSelect(S1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2);
     if (Result != MayAlias)
       return AliasCache[Locs] = Result;
   }
@@ -1667,9 +1756,9 @@ bool BasicAAResult::constantOffsetHeuristic(
 // BasicAliasAnalysis Pass
 //===----------------------------------------------------------------------===//
 
-char BasicAA::PassID;
+AnalysisKey BasicAA::Key;
 
-BasicAAResult BasicAA::run(Function &F, AnalysisManager<Function> &AM) {
+BasicAAResult BasicAA::run(Function &F, FunctionAnalysisManager &AM) {
   return BasicAAResult(F.getParent()->getDataLayout(),
                        AM.getResult<TargetLibraryAnalysis>(F),
                        AM.getResult<AssumptionAnalysis>(F),