diff --git a/llvm/include/llvm/Target/TargetData.h b/llvm/include/llvm/Target/TargetData.h
index 5756079c40f28739b31e8b8a3fdbb505d8a30e56..b51b519fb6d047d8824b07a39b1b60a5d104d18c 100644
--- a/llvm/include/llvm/Target/TargetData.h
+++ b/llvm/include/llvm/Target/TargetData.h
@@ -115,13 +115,13 @@ public:
   }
     
   /// Constructs a TargetData from a specification string. See init().
-  TargetData(const std::string &TargetDescription) 
+  explicit TargetData(const std::string &TargetDescription) 
     : ImmutablePass((intptr_t)&ID) {
     init(TargetDescription);
   }
 
   /// Initialize target data from properties stored in the module.
-  TargetData(const Module *M);
+  explicit TargetData(const Module *M);
 
   TargetData(const TargetData &TD) : 
     ImmutablePass((intptr_t)&ID),
diff --git a/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h b/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h
index 323885002ce989c8726cc2b9cb0693024a460e2d..9ad837c31b4b8051130bf84952653eb1cfd59624 100644
--- a/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h
+++ b/llvm/lib/ExecutionEngine/Interpreter/Interpreter.h
@@ -94,7 +94,7 @@ class Interpreter : public ExecutionEngine, public InstVisitor<Interpreter> {
   std::vector<Function*> AtExitHandlers;
 
 public:
-  Interpreter(Module *M);
+  explicit Interpreter(Module *M);
   ~Interpreter();
 
   /// runAtExitHandlers - Run any functions registered by the program's calls to
diff --git a/llvm/lib/Target/ARM/ARMFrameInfo.h b/llvm/lib/Target/ARM/ARMFrameInfo.h
index c56640a35459e847cab75fb927bc05b84013c114..67ea7b6ce37d89e32d12fc0acb5466460f4db28b 100644
--- a/llvm/lib/Target/ARM/ARMFrameInfo.h
+++ b/llvm/lib/Target/ARM/ARMFrameInfo.h
@@ -23,7 +23,7 @@ namespace llvm {
 
 class ARMFrameInfo : public TargetFrameInfo {
 public:
-  ARMFrameInfo(const ARMSubtarget &ST)
+  explicit ARMFrameInfo(const ARMSubtarget &ST)
     : TargetFrameInfo(StackGrowsDown, ST.getStackAlignment(), 0) {
   }
 };
diff --git a/llvm/utils/TableGen/CallingConvEmitter.h b/llvm/utils/TableGen/CallingConvEmitter.h
index a0bfab3e75cfe19fbb494fde306c7591f08fe349..b63fc82fe046e8c51d86572f8e3665462b413a74 100644
--- a/llvm/utils/TableGen/CallingConvEmitter.h
+++ b/llvm/utils/TableGen/CallingConvEmitter.h
@@ -24,7 +24,7 @@ namespace llvm {
   class CallingConvEmitter : public TableGenBackend {
     RecordKeeper &Records;
   public:
-    CallingConvEmitter(RecordKeeper &R) : Records(R) {}
+    explicit CallingConvEmitter(RecordKeeper &R) : Records(R) {}
 
     // run - Output the asmwriter, returning true on failure.
     void run(std::ostream &o);