diff --git a/emscripten-version.txt b/emscripten-version.txt
index 29d93075197..6c1f3860487 100644
--- a/emscripten-version.txt
+++ b/emscripten-version.txt
@@ -1,2 +1,2 @@
-1.34.4
+1.34.5
 
diff --git a/lib/Target/JSBackend/CallHandlers.h b/lib/Target/JSBackend/CallHandlers.h
index 343ab54bf03..9fc1d274a30 100644
--- a/lib/Target/JSBackend/CallHandlers.h
+++ b/lib/Target/JSBackend/CallHandlers.h
@@ -80,7 +80,7 @@ DEF_CALL_HANDLER(__default__, {
           Name = std::string("FUNCTION_TABLE_") + Sig + "[" + Name + " & #FM_" + Sig + "#]";
           NeedCasts = false; // function table call, so stays in asm module
         } else {
-          Name = std::string("ftCall_") + Sig + "(" + getCast(Name, Type::getInt32Ty(CI->getContext()));
+          Name = std::string(Relocatable ? "mftCall_" : "ftCall_") + Sig + "(" + getCast(Name, Type::getInt32Ty(CI->getContext()));
           if (NumArgs > 0) Name += ',';
           Emulated = true;
         }
diff --git a/lib/Transforms/NaCl/PromoteIntegers.cpp b/lib/Transforms/NaCl/PromoteIntegers.cpp
index 13348ec1ec6..956d82e7f3b 100644
--- a/lib/Transforms/NaCl/PromoteIntegers.cpp
+++ b/lib/Transforms/NaCl/PromoteIntegers.cpp
@@ -635,7 +635,7 @@ static void convertInstruction(DataLayout *DL, Instruction *Inst,
 
 static bool processFunction(Function &F, DataLayout &DL) {
   ConversionState State;
-  bool Modified;
+  bool Modified = false; // XXX Emscripten: Fixed use of an uninitialized variable.
   for (auto FI = F.begin(), FE = F.end(); FI != FE; ++FI) {
     for (auto BBI = FI->begin(), BBE = FI->end(); BBI != BBE;) {
       Instruction *Inst = BBI++;
diff --git a/tools/opt/CMakeLists.txt b/tools/opt/CMakeLists.txt
index 0d834c9413a..cddfe9e67b7 100644
--- a/tools/opt/CMakeLists.txt
+++ b/tools/opt/CMakeLists.txt
@@ -7,6 +7,7 @@ set(LLVM_LINK_COMPONENTS
   IPA
   IPO
   IRReader
+  Linker
   # @LOCALMOD-BEGIN
   NaClAnalysis
   NaClBitWriter
diff --git a/tools/opt/LLVMBuild.txt b/tools/opt/LLVMBuild.txt
index cd2e4156fc7..03f20b75abe 100644
--- a/tools/opt/LLVMBuild.txt
+++ b/tools/opt/LLVMBuild.txt
@@ -19,4 +19,4 @@
 type = Tool
 name = opt
 parent = Tools
-required_libraries = NaClBitWriter NaClTransforms NaClAnalysis MinSFITransforms AsmParser BitReader BitWriter CodeGen IRReader IPO Instrumentation Scalar ObjCARC Passes all-targets
+required_libraries = NaClBitWriter NaClTransforms NaClAnalysis MinSFITransforms AsmParser BitReader BitWriter CodeGen IRReader IPO Instrumentation Linker Scalar ObjCARC Passes all-targets
diff --git a/tools/opt/Makefile b/tools/opt/Makefile
index 3cc54cccb6d..20737abb51f 100644
--- a/tools/opt/Makefile
+++ b/tools/opt/Makefile
@@ -9,7 +9,7 @@
 
 LEVEL := ../..
 TOOLNAME := opt
-LINK_COMPONENTS := naclbitwriter nacltransforms naclanalysis minsfitransforms jsbackend bitreader bitwriter asmparser irreader instrumentation scalaropts objcarcopts ipo vectorize all-targets codegen passes
+LINK_COMPONENTS := naclbitwriter nacltransforms naclanalysis minsfitransforms jsbackend bitreader bitwriter asmparser irreader instrumentation scalaropts objcarcopts ipo vectorize all-targets codegen passes linker
 
 # Support plugins.
 NO_DEAD_STRIP := 1
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index 5ae2322888b..18221607e8d 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -34,6 +34,7 @@
 #include "llvm/IR/Verifier.h"
 #include "llvm/IRReader/IRReader.h"
 #include "llvm/InitializePasses.h"
+#include "llvm/Linker/Linker.h"
 #include "llvm/LinkAllIR.h"
 #include "llvm/LinkAllPasses.h"
 #include "llvm/MC/SubtargetFeature.h"
@@ -76,9 +77,9 @@ static cl::opt<std::string> PassPipeline(
 
 // Other command line options...
 //
-static cl::opt<std::string>
-InputFilename(cl::Positional, cl::desc("<input bitcode file>"),
-    cl::init("-"), cl::value_desc("filename"));
+static cl::list<std::string> // XXX EMSCRIPTEN: support multiple input files, link them
+InputFilenames(cl::Positional, cl::ZeroOrMore,
+               cl::desc("<input bitcode files>"));
 
 static cl::opt<std::string>
 OutputFilename("o", cl::desc("Override output filename"),
@@ -462,7 +463,40 @@ int main(int argc, char **argv) {
   SMDiagnostic Err;
 
   // Load the input module...
-  std::unique_ptr<Module> M = parseIRFile(InputFilename, Err, Context);
+  std::unique_ptr<Module> M;
+
+  // XXX EMSCRIPTEN: support for multiple files
+  if (InputFilenames.size() == 0)
+    M = parseIRFile("-", Err, Context);
+  else if (InputFilenames.size() == 1)
+    M = parseIRFile(InputFilenames[0], Err, Context);
+  else {
+    // link them in
+    M = nullptr;
+    std::unique_ptr<Linker> L;
+
+    for (unsigned i = 0; i < InputFilenames.size(); ++i) {
+      std::unique_ptr<Module> MM = parseIRFile(InputFilenames[i], Err, Context);
+      if (!MM.get()) {
+        errs() << argv[0] << ": error loading file '" <<InputFilenames[i]<< "'\n";
+        return 1;
+      }
+
+      if (!NoVerify && verifyModule(*MM, &errs())) {
+        errs() << argv[0] << ": " << InputFilenames[i]
+               << ": error: input module is broken!\n";
+        return 1;
+      }
+
+      if (i == 0) {
+        M.swap(MM);
+        L = make_unique<Linker>(M.get());
+      } else {
+        if (L->linkInModule(MM.get()))
+          return 1;
+      }
+    }
+  }
 
   if (!M) {
     Err.print(argv[0], errs());
@@ -477,7 +511,7 @@ int main(int argc, char **argv) {
   // pass pipelines.  Otherwise we can crash on broken code during
   // doInitialization().
   if (!NoVerify && verifyModule(*M, &errs())) {
-    errs() << argv[0] << ": " << InputFilename
+    errs() << argv[0] << ": "
            << ": error: input module is broken!\n";
     return 1;
   }