diff --git a/include/llvm/ADT/FoldingSet.h b/include/llvm/ADT/FoldingSet.h
index cce1eec..7629301 100644
--- a/include/llvm/ADT/FoldingSet.h
+++ b/include/llvm/ADT/FoldingSet.h
@@ -317,7 +317,7 @@
 template<class T>
 class FoldingSetIterator : public FoldingSetIteratorImpl {
 public:
-  FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {}
+  explicit FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {}
   
   T &operator*() const {
     return *static_cast<T*>(NodePtr);
@@ -345,7 +345,7 @@
 protected:
   void *Ptr;
 
-  FoldingSetBucketIteratorImpl(void **Bucket);
+  explicit FoldingSetBucketIteratorImpl(void **Bucket);
   
   FoldingSetBucketIteratorImpl(void **Bucket, bool)
     : Ptr(reinterpret_cast<void*>(Bucket)) {}
@@ -369,7 +369,7 @@
 template<class T>
 class FoldingSetBucketIterator : public FoldingSetBucketIteratorImpl {
 public:
-  FoldingSetBucketIterator(void **Bucket) : 
+  explicit FoldingSetBucketIterator(void **Bucket) : 
     FoldingSetBucketIteratorImpl(Bucket) {}
   
   FoldingSetBucketIterator(void **Bucket, bool) : 
@@ -394,7 +394,7 @@
 class FoldingSetNodeWrapper : public FoldingSetNode {
   T data;
 public:
-  FoldingSetNodeWrapper(const T& x) : data(x) {}
+  explicit FoldingSetNodeWrapper(const T& x) : data(x) {}
   virtual ~FoldingSetNodeWrapper() {}
   
   template<typename A1>
diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index dff1624..ff2c3ca 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -611,7 +611,7 @@
   
 private:
   friend class LoopInfoBase<BlockT>;
-  LoopBase(BlockT *BB) : ParentLoop(0) {
+  explicit LoopBase(BlockT *BB) : ParentLoop(0) {
     Blocks.push_back(BB);
   }
 };
diff --git a/include/llvm/Support/Timer.h b/include/llvm/Support/Timer.h
index 3d3a334..4164ddc 100644
--- a/include/llvm/Support/Timer.h
+++ b/include/llvm/Support/Timer.h
@@ -44,7 +44,7 @@
   bool Started;          // Has this time variable ever been started?
   TimerGroup *TG;        // The TimerGroup this Timer is in.
 public:
-  Timer(const std::string &N);
+  explicit Timer(const std::string &N);
   Timer(const std::string &N, TimerGroup &tg);
   Timer(const Timer &T);
   ~Timer();
@@ -116,7 +116,7 @@
   Timer &T;
   TimeRegion(const TimeRegion &); // DO NOT IMPLEMENT
 public:
-  TimeRegion(Timer &t) : T(t) {
+  explicit TimeRegion(Timer &t) : T(t) {
     T.startTimer();
   }
   ~TimeRegion() {
@@ -131,7 +131,7 @@
 /// is primarily used for debugging and for hunting performance problems.
 ///
 struct NamedRegionTimer : public TimeRegion {
-  NamedRegionTimer(const std::string &Name);
+  explicit NamedRegionTimer(const std::string &Name);
 };
 
 
@@ -145,7 +145,7 @@
   unsigned NumTimers;
   std::vector<Timer> TimersToPrint;
 public:
-  TimerGroup(const std::string &name) : Name(name), NumTimers(0) {}
+  explicit TimerGroup(const std::string &name) : Name(name), NumTimers(0) {}
   ~TimerGroup() {
     assert(NumTimers == 0 &&
            "TimerGroup destroyed before all contained timers!");
diff --git a/include/llvm/Transforms/Utils/BasicInliner.h b/include/llvm/Transforms/Utils/BasicInliner.h
index e2070f9..6a57055 100644
--- a/include/llvm/Transforms/Utils/BasicInliner.h
+++ b/include/llvm/Transforms/Utils/BasicInliner.h
@@ -30,7 +30,7 @@
   class BasicInliner {
   public:
     
-    BasicInliner(TargetData *T = NULL);
+    explicit BasicInliner(TargetData *T = NULL);
     ~BasicInliner();
 
     /// addFunction - Add function into the list of functions to process.
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 5cf637e..a3f268f 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -122,8 +122,7 @@
   }
 
 public:
-
-  SelectionDAGLegalize(SelectionDAG &DAG);
+  explicit SelectionDAGLegalize(SelectionDAG &DAG);
 
   /// getTypeAction - Return how we should legalize values of this type, either
   /// it is already legal or we need to expand it into multiple registers of
diff --git a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index de43d6c..c2089c6 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -284,7 +284,7 @@
     public SelectionDAG::DAGUpdateListener {
     DAGTypeLegalizer &DTL;
   public:
-    NodeUpdateListener(DAGTypeLegalizer &dtl) : DTL(dtl) {}
+    explicit NodeUpdateListener(DAGTypeLegalizer &dtl) : DTL(dtl) {}
 
     virtual void NodeDeleted(SDNode *N, SDNode *E) {
       assert(N->getNodeId() != DAGTypeLegalizer::Processed &&
diff --git a/lib/Target/ARM/ARMISelDAGToDAG.cpp b/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 34f6cb9..37d647b 100644
--- a/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -44,7 +44,7 @@
   const ARMSubtarget *Subtarget;
 
 public:
-  ARMDAGToDAGISel(ARMTargetMachine &TM)
+  explicit ARMDAGToDAGISel(ARMTargetMachine &TM)
     : SelectionDAGISel(Lowering), Lowering(TM),
     Subtarget(&TM.getSubtarget<ARMSubtarget>()) {
   }
diff --git a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
index 6bc69ee..a672b13 100644
--- a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
+++ b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
@@ -227,7 +227,7 @@
   unsigned GlobalBaseReg;
 
 public:
-  SPUDAGToDAGISel(SPUTargetMachine &tm) :
+  explicit SPUDAGToDAGISel(SPUTargetMachine &tm) :
     SelectionDAGISel(*tm.getTargetLowering()),
     TM(tm),
     SPUtli(*tm.getTargetLowering())
diff --git a/lib/Target/IA64/IA64ISelDAGToDAG.cpp b/lib/Target/IA64/IA64ISelDAGToDAG.cpp
index dcd1fe2..85c10fe 100644
--- a/lib/Target/IA64/IA64ISelDAGToDAG.cpp
+++ b/lib/Target/IA64/IA64ISelDAGToDAG.cpp
@@ -40,7 +40,7 @@
     IA64TargetLowering IA64Lowering;
     unsigned GlobalBaseReg;
   public:
-    IA64DAGToDAGISel(IA64TargetMachine &TM)
+    explicit IA64DAGToDAGISel(IA64TargetMachine &TM)
       : SelectionDAGISel(IA64Lowering), IA64Lowering(*TM.getTargetLowering()) {}
     
     virtual bool runOnFunction(Function &Fn) {
diff --git a/lib/Target/Mips/MipsISelDAGToDAG.cpp b/lib/Target/Mips/MipsISelDAGToDAG.cpp
index 4822e01..c5d3abd 100644
--- a/lib/Target/Mips/MipsISelDAGToDAG.cpp
+++ b/lib/Target/Mips/MipsISelDAGToDAG.cpp
@@ -61,7 +61,8 @@
   const MipsSubtarget &Subtarget;
  
 public:
-  MipsDAGToDAGISel(MipsTargetMachine &tm) : SelectionDAGISel(MipsLowering),
+  explicit MipsDAGToDAGISel(MipsTargetMachine &tm) :
+  SelectionDAGISel(MipsLowering),
   TM(tm), MipsLowering(*TM.getTargetLowering()), 
   Subtarget(tm.getSubtarget<MipsSubtarget>()) {}
   
diff --git a/lib/Target/PIC16/PIC16ISelDAGToDAG.cpp b/lib/Target/PIC16/PIC16ISelDAGToDAG.cpp
index 325e71e..402566f 100644
--- a/lib/Target/PIC16/PIC16ISelDAGToDAG.cpp
+++ b/lib/Target/PIC16/PIC16ISelDAGToDAG.cpp
@@ -57,7 +57,7 @@
   PIC16TargetLowering PIC16Lowering;
 
 public:
-  PIC16DAGToDAGISel(PIC16TargetMachine &tm) : 
+  explicit PIC16DAGToDAGISel(PIC16TargetMachine &tm) : 
         SelectionDAGISel(PIC16Lowering),
         TM(tm), PIC16Lowering(*TM.getTargetLowering()) {}
   
diff --git a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 1dea2ee..09563c4 100644
--- a/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -45,7 +45,7 @@
     const PPCSubtarget &PPCSubTarget;
     unsigned GlobalBaseReg;
   public:
-    PPCDAGToDAGISel(PPCTargetMachine &tm)
+    explicit PPCDAGToDAGISel(PPCTargetMachine &tm)
       : SelectionDAGISel(PPCLowering), TM(tm),
         PPCLowering(*TM.getTargetLowering()),
         PPCSubTarget(*TM.getSubtargetImpl()) {}
diff --git a/lib/Target/Sparc/SparcISelDAGToDAG.cpp b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
index 50690ca..df07d51 100644
--- a/lib/Target/Sparc/SparcISelDAGToDAG.cpp
+++ b/lib/Target/Sparc/SparcISelDAGToDAG.cpp
@@ -35,7 +35,7 @@
   /// make the right decision when generating code for different targets.
   const SparcSubtarget &Subtarget;
 public:
-  SparcDAGToDAGISel(TargetMachine &TM)
+  explicit SparcDAGToDAGISel(TargetMachine &TM)
     : SelectionDAGISel(Lowering), Lowering(TM),
       Subtarget(TM.getSubtarget<SparcSubtarget>()) {
   }
diff --git a/lib/VMCore/LeakDetector.cpp b/lib/VMCore/LeakDetector.cpp
index 9f3584e..4ad75b7 100644
--- a/lib/VMCore/LeakDetector.cpp
+++ b/lib/VMCore/LeakDetector.cpp
@@ -31,7 +31,7 @@
 
   template <typename T>
   struct VISIBILITY_HIDDEN LeakDetectorImpl {
-    LeakDetectorImpl(const char* const name) : Cache(0), Name(name) { }
+    explicit LeakDetectorImpl(const char* const name) : Cache(0), Name(name) { }
 
     // Because the most common usage pattern, by far, is to add a
     // garbage object, then remove it immediately, we optimize this
diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index f172130..90258ed 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -431,7 +431,7 @@
 
 namespace {
   struct BuiltinIntegerType : public IntegerType {
-    BuiltinIntegerType(unsigned W) : IntegerType(W) {}
+    explicit BuiltinIntegerType(unsigned W) : IntegerType(W) {}
   };
 }
 const IntegerType *Type::Int1Ty  = new BuiltinIntegerType(1);
diff --git a/utils/TableGen/Record.h b/utils/TableGen/Record.h
index 83d358a..c36d808 100644
--- a/utils/TableGen/Record.h
+++ b/utils/TableGen/Record.h
@@ -151,7 +151,7 @@
 class BitsRecTy : public RecTy {
   unsigned Size;
 public:
-  BitsRecTy(unsigned Sz) : Size(Sz) {}
+  explicit BitsRecTy(unsigned Sz) : Size(Sz) {}
 
   unsigned getNumBits() const { return Size; }
 
@@ -268,7 +268,7 @@
 class ListRecTy : public RecTy {
   RecTy *Ty;
 public:
-  ListRecTy(RecTy *T) : Ty(T) {}
+  explicit ListRecTy(RecTy *T) : Ty(T) {}
 
   RecTy *getElementType() const { return Ty; }
 
@@ -381,7 +381,7 @@
 class RecordRecTy : public RecTy {
   Record *Rec;
 public:
-  RecordRecTy(Record *R) : Rec(R) {}
+  explicit RecordRecTy(Record *R) : Rec(R) {}
 
   Record *getRecord() const { return Rec; }
 
@@ -966,7 +966,7 @@
   std::vector<Record*> SuperClasses;
 public:
 
-  Record(const std::string &N) : Name(N) {}
+  explicit Record(const std::string &N) : Name(N) {}
   ~Record() {}
 
   const std::string &getName() const { return Name; }