Index: zorg/buildbot/builders/LLDBBuilder.py
===================================================================
--- zorg/buildbot/builders/LLDBBuilder.py
+++ zorg/buildbot/builders/LLDBBuilder.py
@@ -15,17 +15,17 @@
 # We *must* checkout at least Clang, LLVM, and LLDB.  Once we add a step to run
 # tests (e.g. ninja check-lldb), we will also need to add a step for LLD, since
 # MSVC LD.EXE cannot link executables with DWARF debug info.
-def getLLDBSource(f,llvmTopDir='llvm'):
+def getLLDBSource(f,svnMode,llvmTopDir='llvm'):
     f.addStep(SVN(name='svn-llvm',
-                  mode='update', baseURL='http://llvm.org/svn/llvm-project/llvm/',
+                  mode=svnMode, baseURL='http://llvm.org/svn/llvm-project/llvm/',
                   defaultBranch='trunk',
                   workdir=llvmTopDir))
     f.addStep(SVN(name='svn-clang',
-                  mode='update', baseURL='http://llvm.org/svn/llvm-project/cfe/',
+                  mode=svnMode, baseURL='http://llvm.org/svn/llvm-project/cfe/',
                   defaultBranch='trunk',
                   workdir='%s/tools/clang' % llvmTopDir))
     f.addStep(SVN(name='svn-lldb',
-                  mode='update', baseURL='http://llvm.org/svn/llvm-project/lldb/',
+                  mode=svnMode, baseURL='http://llvm.org/svn/llvm-project/lldb/',
                   defaultBranch='trunk',
                   workdir='%s/tools/lldb' % llvmTopDir))
     return f
@@ -56,7 +56,8 @@
         command=getVisualStudioEnvironment(vs, target_arch),
         extract_fn=extractSlaveEnvironment))
 
-    f = getLLDBSource(f,'llvm')
+    mode = step.build.getProperty("mode") or 'update'
+    f = getLLDBSource(f,mode,'llvm')
 
     build_cmd=['ninja']
     install_cmd = ['ninja','install']
@@ -254,7 +255,7 @@
                           description="set build dir",
                           workdir="."))
     # Get source code
-    f = getLLDBSource(f,llvm_srcdir)
+    f = getLLDBSource(f,'update',llvm_srcdir)
 
     # Construct cmake
     cmake_args = ["cmake", "-GNinja"]