diff --git a/lib/Target/ARM/ARMMachineFunctionInfo.h b/lib/Target/ARM/ARMMachineFunctionInfo.h
index 6662be12a57..0b0e2892828 100644
--- a/lib/Target/ARM/ARMMachineFunctionInfo.h
+++ b/lib/Target/ARM/ARMMachineFunctionInfo.h
@@ -100,7 +100,7 @@ public:
     GPRCS1Frames(0), GPRCS2Frames(0), DPRCSFrames(0),
     JumpTableUId(0), ConstPoolEntryUId(0) {}
 
-  ARMFunctionInfo(MachineFunction &MF) :
+  explicit ARMFunctionInfo(MachineFunction &MF) :
     isThumb(MF.getTarget().getSubtarget<ARMSubtarget>().isThumb()),
     Align(isThumb ? 1U : 2U),
     VarArgsRegSaveSize(0), HasStackFrame(false),
diff --git a/lib/Target/Alpha/AlphaMachineFunctionInfo.h b/lib/Target/Alpha/AlphaMachineFunctionInfo.h
index 47de5dfad94..8221fc7a7c9 100644
--- a/lib/Target/Alpha/AlphaMachineFunctionInfo.h
+++ b/lib/Target/Alpha/AlphaMachineFunctionInfo.h
@@ -33,8 +33,8 @@ class AlphaMachineFunctionInfo : public MachineFunctionInfo {
 public:
   AlphaMachineFunctionInfo() : GlobalBaseReg(0), GlobalRetAddr(0) {}
 
-  AlphaMachineFunctionInfo(MachineFunction &MF) : GlobalBaseReg(0),
-                                                  GlobalRetAddr(0) {}
+  explicit AlphaMachineFunctionInfo(MachineFunction &MF) : GlobalBaseReg(0),
+                                                           GlobalRetAddr(0) {}
 
   unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
   void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }
diff --git a/lib/Target/IA64/IA64MachineFunctionInfo.h b/lib/Target/IA64/IA64MachineFunctionInfo.h
index fb930564a9d..e6254d69d6a 100644
--- a/lib/Target/IA64/IA64MachineFunctionInfo.h
+++ b/lib/Target/IA64/IA64MachineFunctionInfo.h
@@ -24,7 +24,7 @@ public:
   // by this machinefunction? (used to compute the appropriate
   // entry in the 'alloc' instruction at the top of the
   // machinefunction)
-  IA64FunctionInfo(MachineFunction& MF) { outRegsUsed=0; };
+  explicit IA64FunctionInfo(MachineFunction& MF) { outRegsUsed=0; };
 
 };
 
diff --git a/lib/Target/MSP430/MSP430MachineFunctionInfo.h b/lib/Target/MSP430/MSP430MachineFunctionInfo.h
index b94d7e44cac..1d26ae3e667 100644
--- a/lib/Target/MSP430/MSP430MachineFunctionInfo.h
+++ b/lib/Target/MSP430/MSP430MachineFunctionInfo.h
@@ -28,7 +28,8 @@ class MSP430MachineFunctionInfo : public MachineFunctionInfo {
 public:
   MSP430MachineFunctionInfo() : CalleeSavedFrameSize(0) {}
 
-  MSP430MachineFunctionInfo(MachineFunction &MF) : CalleeSavedFrameSize(0) {}
+  explicit MSP430MachineFunctionInfo(MachineFunction &MF)
+    : CalleeSavedFrameSize(0) {}
 
   unsigned getCalleeSavedFrameSize() const { return CalleeSavedFrameSize; }
   void setCalleeSavedFrameSize(unsigned bytes) { CalleeSavedFrameSize = bytes; }
diff --git a/lib/Target/PowerPC/PPCMachineFunctionInfo.h b/lib/Target/PowerPC/PPCMachineFunctionInfo.h
index 42883d78728..b359dd33bd0 100644
--- a/lib/Target/PowerPC/PPCMachineFunctionInfo.h
+++ b/lib/Target/PowerPC/PPCMachineFunctionInfo.h
@@ -59,7 +59,7 @@ private:
   bool HasFastCall;
 
 public:
-  PPCFunctionInfo(MachineFunction &MF) 
+  explicit PPCFunctionInfo(MachineFunction &MF) 
     : FramePointerSaveIndex(0),
       ReturnAddrSaveIndex(0),
       SpillsCR(false),
diff --git a/lib/Target/X86/X86MachineFunctionInfo.h b/lib/Target/X86/X86MachineFunctionInfo.h
index 8a5ac2c9a85..fafcf7e3d79 100644
--- a/lib/Target/X86/X86MachineFunctionInfo.h
+++ b/lib/Target/X86/X86MachineFunctionInfo.h
@@ -73,14 +73,15 @@ public:
                              SRetReturnReg(0),
                              GlobalBaseReg(0) {}
   
-  X86MachineFunctionInfo(MachineFunction &MF) : ForceFramePointer(false),
-                                                CalleeSavedFrameSize(0),
-                                                BytesToPopOnReturn(0),
-                                                DecorationStyle(None),
-                                                ReturnAddrIndex(0),
-                                                TailCallReturnAddrDelta(0),
-                                                SRetReturnReg(0),
-                                                GlobalBaseReg(0) {}
+  explicit X86MachineFunctionInfo(MachineFunction &MF)
+    : ForceFramePointer(false),
+      CalleeSavedFrameSize(0),
+      BytesToPopOnReturn(0),
+      DecorationStyle(None),
+      ReturnAddrIndex(0),
+      TailCallReturnAddrDelta(0),
+      SRetReturnReg(0),
+      GlobalBaseReg(0) {}
   
   bool getForceFramePointer() const { return ForceFramePointer;} 
   void setForceFramePointer(bool forceFP) { ForceFramePointer = forceFP; }
diff --git a/lib/Target/XCore/XCoreMachineFunctionInfo.h b/lib/Target/XCore/XCoreMachineFunctionInfo.h
index 43adb0f917c..124a011f3cb 100644
--- a/lib/Target/XCore/XCoreMachineFunctionInfo.h
+++ b/lib/Target/XCore/XCoreMachineFunctionInfo.h
@@ -40,7 +40,7 @@ public:
     FPSpillSlot(0),
     VarArgsFrameIndex(0) {}
   
-  XCoreFunctionInfo(MachineFunction &MF) :
+  explicit XCoreFunctionInfo(MachineFunction &MF) :
     UsesLR(false),
     LRSpillSlot(0),
     FPSpillSlot(0),