Index: llvm/trunk/tools/msbuild/LLVM.Cpp.Common.props
===================================================================
--- llvm/trunk/tools/msbuild/LLVM.Cpp.Common.props
+++ llvm/trunk/tools/msbuild/LLVM.Cpp.Common.props
@@ -42,8 +42,10 @@
     <LLVMInstallDir Condition="'$(LLVMInstallDir)' != ''">$(LLVMInstallDir)\</LLVMInstallDir>
     <ClangClExecutable>$(LLVMInstallDir)bin\clang-cl.exe</ClangClExecutable>
     <LldLinkExecutable>$(LLVMInstallDir)bin\lld-link.exe</LldLinkExecutable>
+    <LlvmLibExecutable>$(LLVMInstallDir)bin\llvm-lib.exe</LlvmLibExecutable>
     <UseClangCl>true</UseClangCl>
     <UseLldLink>true</UseLldLink>
+    <UseLlvmLib>true</UseLlvmLib>
   </PropertyGroup>
 
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.WindowsSDK.props" Condition="Exists('$(VCTargetsPath)\Microsoft.Cpp.WindowsSDK.props')"/>
Index: llvm/trunk/tools/msbuild/LLVM.Cpp.Common.targets
===================================================================
--- llvm/trunk/tools/msbuild/LLVM.Cpp.Common.targets
+++ llvm/trunk/tools/msbuild/LLVM.Cpp.Common.targets
@@ -9,6 +9,7 @@
          that the user may have overridden in the UI. -->
     <CLToolExe Condition="$(UseClangCl)">$(ClangClExecutable)</CLToolExe>
     <LinkToolExe Condition="$(UseLldLink)">$(LldLinkExecutable)</LinkToolExe>
+    <LIBToolExe Condition="$(UseLlvmLib)">$(LlvmLibExecutable)</LIBToolExe>
   </PropertyGroup>
 
   <ItemGroup>
Index: llvm/trunk/tools/msbuild/llvm-general.xml
===================================================================
--- llvm/trunk/tools/msbuild/llvm-general.xml
+++ llvm/trunk/tools/msbuild/llvm-general.xml
@@ -52,4 +52,25 @@
                   Category="General">
   </StringProperty>
 
+
+  <BoolProperty Name="UseLlvmLib"
+                DisplayName="Use llvm-lib"
+                Description="Use llvm-lib for managing libraries.  If this option is disabled, the Microsoft librarian (lib.exe) will be used instead."
+                Category="General"
+                Default="true">
+  </BoolProperty>
+  <StringProperty Name="LlvmLibExecutable"
+                  DisplayName="llvm-lib Executable"
+                  Description="Specifies the path to llvm-lib.exe."
+                  Category="General"
+                  Default="$(LLVMInstallDir)bin\llvm-lib.exe"
+                  Subtype="file">
+  </StringProperty>
+
+  <StringProperty Name="LlvmLibAdditionalOptions"
+                  DisplayName="Additional Librarian Options"
+                  Description="Additional options to pass to llvm-lib.  This is essentially the same as General > Librarian > Command Line > Additional Options, except that it is safe to put options here that will be rejected by lib.exe in case you switch toolchains back and forth."
+                  Category="General">
+  </StringProperty>
+
 </Rule>