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, 118 insertions, 0 deletions

diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
index 98582ba..2ae3286 100644
--- a/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
+++ b/contrib/llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
@@ -219,6 +219,7 @@ void FunctionLoweringInfo::clear() {
   CatchInfoFound.clear();
 #endif
   LiveOutRegInfo.clear();
+  VisitedBBs.clear();
   ArgDbgValues.clear();
   ByValArgFrameIndexMap.clear();
   RegFixups.clear();
@@ -254,6 +255,123 @@ unsigned FunctionLoweringInfo::CreateRegs(const Type *Ty) {
   return FirstReg;
 }
 
+/// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
+/// register is a PHI destination and the PHI's LiveOutInfo is not valid. If
+/// the register's LiveOutInfo is for a smaller bit width, it is extended to
+/// the larger bit width by zero extension. The bit width must be no smaller
+/// than the LiveOutInfo's existing bit width.
+const FunctionLoweringInfo::LiveOutInfo *
+FunctionLoweringInfo::GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth) {
+  if (!LiveOutRegInfo.inBounds(Reg))
+    return NULL;
+
+  LiveOutInfo *LOI = &LiveOutRegInfo[Reg];
+  if (!LOI->IsValid)
+    return NULL;
+
+  if (BitWidth > LOI->KnownZero.getBitWidth()) {
+    LOI->NumSignBits = 1;
+    LOI->KnownZero = LOI->KnownZero.zextOrTrunc(BitWidth);
+    LOI->KnownOne = LOI->KnownOne.zextOrTrunc(BitWidth);
+  }
+
+  return LOI;
+}
+
+/// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination
+/// register based on the LiveOutInfo of its operands.
+void FunctionLoweringInfo::ComputePHILiveOutRegInfo(const PHINode *PN) {
+  const Type *Ty = PN->getType();
+  if (!Ty->isIntegerTy() || Ty->isVectorTy())
+    return;
+
+  SmallVector<EVT, 1> ValueVTs;
+  ComputeValueVTs(TLI, Ty, ValueVTs);
+  assert(ValueVTs.size() == 1 &&
+         "PHIs with non-vector integer types should have a single VT.");
+  EVT IntVT = ValueVTs[0];
+
+  if (TLI.getNumRegisters(PN->getContext(), IntVT) != 1)
+    return;
+  IntVT = TLI.getTypeToTransformTo(PN->getContext(), IntVT);
+  unsigned BitWidth = IntVT.getSizeInBits();
+
+  unsigned DestReg = ValueMap[PN];
+  if (!TargetRegisterInfo::isVirtualRegister(DestReg))
+    return;
+  LiveOutRegInfo.grow(DestReg);
+  LiveOutInfo &DestLOI = LiveOutRegInfo[DestReg];
+
+  Value *V = PN->getIncomingValue(0);
+  if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) {
+    DestLOI.NumSignBits = 1;
+    APInt Zero(BitWidth, 0);
+    DestLOI.KnownZero = Zero;
+    DestLOI.KnownOne = Zero;
+    return;
+  }
+
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+    APInt Val = CI->getValue().zextOrTrunc(BitWidth);
+    DestLOI.NumSignBits = Val.getNumSignBits();
+    DestLOI.KnownZero = ~Val;
+    DestLOI.KnownOne = Val;
+  } else {
+    assert(ValueMap.count(V) && "V should have been placed in ValueMap when its"
+                                "CopyToReg node was created.");
+    unsigned SrcReg = ValueMap[V];
+    if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) {
+      DestLOI.IsValid = false;
+      return;
+    }
+    const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth);
+    if (!SrcLOI) {
+      DestLOI.IsValid = false;
+      return;
+    }
+    DestLOI = *SrcLOI;
+  }
+
+  assert(DestLOI.KnownZero.getBitWidth() == BitWidth &&
+         DestLOI.KnownOne.getBitWidth() == BitWidth &&
+         "Masks should have the same bit width as the type.");
+
+  for (unsigned i = 1, e = PN->getNumIncomingValues(); i != e; ++i) {
+    Value *V = PN->getIncomingValue(i);
+    if (isa<UndefValue>(V) || isa<ConstantExpr>(V)) {
+      DestLOI.NumSignBits = 1;
+      APInt Zero(BitWidth, 0);
+      DestLOI.KnownZero = Zero;
+      DestLOI.KnownOne = Zero;
+      return;      
+    }
+
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+      APInt Val = CI->getValue().zextOrTrunc(BitWidth);
+      DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, Val.getNumSignBits());
+      DestLOI.KnownZero &= ~Val;
+      DestLOI.KnownOne &= Val;
+      continue;
+    }
+
+    assert(ValueMap.count(V) && "V should have been placed in ValueMap when "
+                                "its CopyToReg node was created.");
+    unsigned SrcReg = ValueMap[V];
+    if (!TargetRegisterInfo::isVirtualRegister(SrcReg)) {
+      DestLOI.IsValid = false;
+      return;
+    }
+    const LiveOutInfo *SrcLOI = GetLiveOutRegInfo(SrcReg, BitWidth);
+    if (!SrcLOI) {
+      DestLOI.IsValid = false;
+      return;
+    }
+    DestLOI.NumSignBits = std::min(DestLOI.NumSignBits, SrcLOI->NumSignBits);
+    DestLOI.KnownZero &= SrcLOI->KnownZero;
+    DestLOI.KnownOne &= SrcLOI->KnownOne;
+  }
+}
+
 /// setByValArgumentFrameIndex - Record frame index for the byval
 /// argument. This overrides previous frame index entry for this argument,
 /// if any.