diff --git a/llvm/include/llvm/Analysis/MemoryBuiltins.h b/llvm/include/llvm/Analysis/MemoryBuiltins.h
index e674e74520d2b22e4edd67c12713df9e79bbfe94..76840829ad29df2258ce15999e037999dff129c2 100644
--- a/llvm/include/llvm/Analysis/MemoryBuiltins.h
+++ b/llvm/include/llvm/Analysis/MemoryBuiltins.h
@@ -201,6 +201,7 @@ class ObjectSizeOffsetEvaluator
   typedef SmallPtrSet<const Value*, 8> PtrSetTy;
 
   const TargetData *TD;
+  const TargetLibraryInfo *TLI;
   LLVMContext &Context;
   BuilderTy Builder;
   ObjectSizeOffsetVisitor Visitor;
@@ -215,7 +216,8 @@ class ObjectSizeOffsetEvaluator
   SizeOffsetEvalType compute_(Value *V);
 
 public:
-  ObjectSizeOffsetEvaluator(const TargetData *TD, LLVMContext &Context);
+  ObjectSizeOffsetEvaluator(const TargetData *TD, const TargetLibraryInfo *TLI,
+                            LLVMContext &Context);
   SizeOffsetEvalType compute(Value *V);
 
   bool knownSize(SizeOffsetEvalType SizeOffset) {
diff --git a/llvm/lib/Analysis/MemoryBuiltins.cpp b/llvm/lib/Analysis/MemoryBuiltins.cpp
index 4833b5212be0e4c963c5d765584309b4c1198d59..21417781bd6ddff3c5d27f2b0bae3add16d0aaae 100644
--- a/llvm/lib/Analysis/MemoryBuiltins.cpp
+++ b/llvm/lib/Analysis/MemoryBuiltins.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/BuildLibCalls.h"
 #include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 
@@ -448,11 +449,9 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitCallSite(CallSite CS) {
   return std::make_pair(Size, Zero);
 
   // TODO: handle more standard functions (+ wchar cousins):
-  // - strdup / strndup
   // - strcpy / strncpy
   // - strcat / strncat
   // - memcpy / memmove
-  // - strcat / strncat
   // - memset
 }
 
@@ -524,8 +523,9 @@ SizeOffsetType ObjectSizeOffsetVisitor::visitInstruction(Instruction &I) {
 
 
 ObjectSizeOffsetEvaluator::ObjectSizeOffsetEvaluator(const TargetData *TD,
+                                                     const TargetLibraryInfo *TLI,
                                                      LLVMContext &Context)
-: TD(TD), Context(Context), Builder(Context, TargetFolder(TD)),
+: TD(TD), TLI(TLI), Context(Context), Builder(Context, TargetFolder(TD)),
 Visitor(TD, Context) {
   IntTy = TD->getIntPtrType(Context);
   Zero = ConstantInt::get(IntTy, 0);
@@ -619,8 +619,21 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
 
   // handle strdup-like functions separately
   if (FnData->AllocTy == StrDupLike) {
-    // TODO
-    return unknown();
+    IRBuilder<> StdBuilder(Builder.GetInsertPoint());
+    Value *Size;
+
+    // strdup(str): size =  strlen(str)+1
+    if (FnData->FstParam < 0)
+      Size = EmitStrLen(CS.getArgument(0), StdBuilder, TD, TLI);
+    else
+      // strndup(str, maxlen): size = strnlen(str, maxlen)+1
+      Size = EmitStrNLen(CS.getArgument(0), CS.getArgument(FnData->FstParam),
+                         StdBuilder, TD, TLI);
+    if (!Size)
+      return unknown();
+    Builder.SetInsertPoint(StdBuilder.GetInsertPoint());
+    Size = Builder.CreateNUWAdd(Size, ConstantInt::get(IntTy, 1));
+    return std::make_pair(Size, Zero);
   }
 
   Value *FirstArg = CS.getArgument(FnData->FstParam);
@@ -634,11 +647,9 @@ SizeOffsetEvalType ObjectSizeOffsetEvaluator::visitCallSite(CallSite CS) {
   return std::make_pair(Size, Zero);
 
   // TODO: handle more standard functions (+ wchar cousins):
-  // - strdup / strndup
   // - strcpy / strncpy
   // - strcat / strncat
   // - memcpy / memmove
-  // - strcat / strncat
   // - memset
 }
 
diff --git a/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp b/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
index 09e0f1445126560375e36c65d8757ff3297db9ff..b209fff61da35b6a02bcd4633df0a44687fda9d0 100644
--- a/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
+++ b/llvm/lib/Transforms/Instrumentation/BoundsChecking.cpp
@@ -24,6 +24,7 @@
 #include "llvm/Support/TargetFolder.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetLibraryInfo.h"
 #include "llvm/Transforms/Instrumentation.h"
 using namespace llvm;
 
@@ -48,6 +49,7 @@ namespace {
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.addRequired<TargetData>();
+      AU.addRequired<TargetLibraryInfo>();
     }
 
   private:
@@ -166,11 +168,12 @@ bool BoundsChecking::instrument(Value *Ptr, Value *InstVal) {
 
 bool BoundsChecking::runOnFunction(Function &F) {
   TD = &getAnalysis<TargetData>();
+  const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
 
   TrapBB = 0;
   BuilderTy TheBuilder(F.getContext(), TargetFolder(TD));
   Builder = &TheBuilder;
-  ObjectSizeOffsetEvaluator TheObjSizeEval(TD, F.getContext());
+  ObjectSizeOffsetEvaluator TheObjSizeEval(TD, TLI, F.getContext());
   ObjSizeEval = &TheObjSizeEval;
 
   // check HANDLE_MEMORY_INST in include/llvm/Instruction.def for memory
diff --git a/llvm/test/Instrumentation/BoundsChecking/strings.ll b/llvm/test/Instrumentation/BoundsChecking/strings.ll
new file mode 100644
index 0000000000000000000000000000000000000000..1942d1407b2a522849a2bde8533579be26e590b5
--- /dev/null
+++ b/llvm/test/Instrumentation/BoundsChecking/strings.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -bounds-checking -S | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+declare noalias i8* @strdup(i8* nocapture) nounwind
+declare noalias i8* @strndup(i8* nocapture, i64) nounwind
+
+; CHECK: @f1
+define i8 @f1(i8* nocapture %str, i8** nocapture %esc) nounwind uwtable ssp {
+; CHECK: call i64 @strlen(i8* %str)
+; CHECK-NEXT: %1 = add nuw i64 {{.*}}, 1
+  %call = tail call i8* @strdup(i8* %str) nounwind
+  store i8* %call, i8** %esc, align 8
+  %arrayidx = getelementptr inbounds i8* %call, i64 3
+; CHECK: sub i64 %1, 3
+  %1 = load i8* %arrayidx, align 1
+  ret i8 %1
+; CHECK: call void @llvm.trap
+}
+
+; CHECK: @f2
+define i8 @f2(i8* nocapture %str, i8** nocapture %esc, i64 %limit) nounwind uwtable ssp {
+; CHECK: call i64 @strnlen(i8* %str, i64 %limit)
+; CHECK-NEXT: %1 = add nuw i64 {{.*}}, 1
+  %call = tail call i8* @strndup(i8* %str, i64 %limit) nounwind
+  store i8* %call, i8** %esc, align 8
+  %arrayidx = getelementptr inbounds i8* %call, i64 3
+; CHECK: sub i64 %1, 3
+  %1 = load i8* %arrayidx, align 1
+  ret i8 %1
+; CHECK: call void @llvm.trap
+}