diff --git a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp
index 68a0f56b..54baf133 100644
--- a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.cpp
@@ -38,11 +38,9 @@ void HeaderSearchDirs::AddCompilerBuiltInSearchDirs () {
 #if __linux
     std::stringstream icg_dir ;
     icg_dir << LLVM_HOME << "/lib/clang/" ;
-    icg_dir << __clang_major__ << "." << __clang_minor__ ;
-#if (__clang_major__ > 3) || ((__clang_major__ == 3) && (__clang_minor__ >= 4))
-#ifdef __clang_patchlevel__
-    icg_dir << "." << __clang_patchlevel__  ;
-#endif
+    icg_dir << LIBCLANG_MAJOR << "." << LIBCLANG_MINOR ;
+#ifdef LIBCLANG_PATCHLEVEL
+    icg_dir << "." << LIBCLANG_PATCHLEVEL  ;
 #endif
     icg_dir << "/include" ;
     char * resolved_path = realpath(icg_dir.str().c_str(), NULL ) ;
@@ -80,11 +78,7 @@ void HeaderSearchDirs::AddCompilerBuiltInSearchDirs () {
             //std::cout << "dir = " << dir << std::endl ;
             if ( resolved_path != NULL ) {
                 //std::cout << "gcc resolved_path = " << resolved_path << std::endl ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
                 hso.AddPath(resolved_path , clang::frontend::System, IsFramework, IsSysRootRelative);
-#else
-                hso.AddPath(resolved_path , clang::frontend::System, IsUserSupplied, IsFramework, IsSysRootRelative);
-#endif
                 free(resolved_path) ;
             }
         } else if ( !strncmp( line, "#include <...>", 14 )) {
@@ -107,11 +101,7 @@ void HeaderSearchDirs::AddUserSearchDirs ( std::vector<std::string> & include_di
         char * resolved_path = almostRealPath(include_dirs[ii].c_str()) ;
         if ( resolved_path != NULL ) {
             //std::cout << "adding resolved_path = " << resolved_path << std::endl ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
             hso.AddPath(resolved_path , clang::frontend::Angled, false, true);
-#else
-            hso.AddPath(resolved_path , clang::frontend::Angled, true, false, true);
-#endif
             // Add the path as a system path as well for those included files that are erroneously in <>
         }
     }
@@ -124,11 +114,7 @@ void HeaderSearchDirs::AddTrickSearchDirs () {
     if ( trick_home != NULL ) {
         std::string temp_dir = std::string(trick_home) + "/trick_source" ;
         char * resolved_path = almostRealPath(temp_dir.c_str() ) ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
         hso.AddPath(resolved_path , clang::frontend::Quoted, false, true);
-#else
-        hso.AddPath(resolved_path , clang::frontend::Quoted, true, false, true);
-#endif
         trick_source_dir = std::string(resolved_path) ;
         free(resolved_path) ;
     }
diff --git a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh
index 87cb4ebb..fb3c6486 100644
--- a/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh
+++ b/trick_source/codegen/Interface_Code_Gen/HeaderSearchDirs.hh
@@ -7,11 +7,7 @@
 #include <string>
 
 #include "clang/Lex/HeaderSearch.h"
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
 #include "clang/Lex/HeaderSearchOptions.h"
-#else
-#include "clang/Frontend/HeaderSearchOptions.h"
-#endif
 #include "clang/Lex/Preprocessor.h"
 
 /**
diff --git a/trick_source/codegen/Interface_Code_Gen/main.cpp b/trick_source/codegen/Interface_Code_Gen/main.cpp
index e663d475..b859ca82 100644
--- a/trick_source/codegen/Interface_Code_Gen/main.cpp
+++ b/trick_source/codegen/Interface_Code_Gen/main.cpp
@@ -62,15 +62,6 @@ Most of the main program is pieced together from examples on the web. We are doi
 */
 int main( int argc , char * argv[] ) {
 
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
-    clang::TargetOptions to;
-#elif (__clang_major__ == 3) && (__clang_minor__ >= 3)
-    clang::TargetOptions * to = new clang::TargetOptions() ;
-#else
-    clang::TargetOptions to;
-#endif
-    clang::CompilerInstance ci;
-
     /* Gather all of the command line arguments into lists of include directories, defines, and input files.
        All other arguments will be ignored. */
     llvm::cl::SetVersionPrinter(ICG_version) ;
@@ -90,67 +81,54 @@ int main( int argc , char * argv[] ) {
         return 1 ;
     }
 
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
-    ci.createDiagnostics();
-#else
-    ci.createDiagnostics(0,NULL);
-#endif
-    clang::DiagnosticOptions & diago = ci.getDiagnosticOpts() ;
-    diago.ShowColors = 1 ;
-    ci.getDiagnostics().setIgnoreAllWarnings(true) ;
-#if ( GCC_MAJOR == 4 ) && ( GCC_MINOR <= 2 )
-    ci.getDiagnostics().setSuppressAllDiagnostics() ;
-#endif
-
-    // Set all of the defaults to c++
+    clang::CompilerInstance ci;
+#if (LIBCLANG_MAJOR == 3) && (LIBCLANG_MINOR < 9)
     clang::CompilerInvocation::setLangDefaults(ci.getLangOpts() , clang::IK_CXX) ;
+#endif
+    ci.createDiagnostics();
+    ci.getDiagnosticOpts().ShowColors = 1 ;
+    ci.getDiagnostics().setIgnoreAllWarnings(true) ;
     ci.getLangOpts().CXXExceptions = true ;
-
     // Activate C++11 parsing
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
+    ci.getLangOpts().Bool = true ;
+    ci.getLangOpts().WChar = true ;
+    ci.getLangOpts().CPlusPlus = true ;
     ci.getLangOpts().CPlusPlus11 = true ;
-#else
-    ci.getLangOpts().CPlusPlus0x = true ;
-#endif
-
-    // Set the default target architecture
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
-    to.Triple = llvm::sys::getDefaultTargetTriple();
-#elif (__clang_major__ == 3) && (__clang_minor__ >= 3)
-    to->Triple = llvm::sys::getDefaultTargetTriple();
-#else
-    to.Triple = llvm::sys::getDefaultTargetTriple();
-#endif
-
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
-    std::shared_ptr<clang::TargetOptions> shared_to  = std::make_shared<clang::TargetOptions>(to) ;
-    clang::TargetInfo *pti = clang::TargetInfo::CreateTargetInfo(ci.getDiagnostics(), shared_to);
-#else
-    clang::TargetInfo *pti = clang::TargetInfo::CreateTargetInfo(ci.getDiagnostics(), to);
-#endif
-    ci.setTarget(pti);
+    ci.getLangOpts().CXXOperatorNames = true ;
 
     // Create all of the necessary managers.
     ci.createFileManager();
     ci.createSourceManager(ci.getFileManager());
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+
+#if (LIBCLANG_MAJOR > 3) || ((LIBCLANG_MAJOR == 3) && (LIBCLANG_MINOR >= 5))
+    clang::TargetOptions to;
+    to.Triple = llvm::sys::getDefaultTargetTriple();
+    std::shared_ptr<clang::TargetOptions> shared_to  = std::make_shared<clang::TargetOptions>(to) ;
+    clang::TargetInfo *pti = clang::TargetInfo::CreateTargetInfo(ci.getDiagnostics(), shared_to);
+    ci.setTarget(pti);
     ci.createPreprocessor(clang::TU_Complete);
 #else
+    clang::TargetOptions * to = new clang::TargetOptions() ;
+    to->Triple = llvm::sys::getDefaultTargetTriple();
+    clang::TargetInfo *pti = clang::TargetInfo::CreateTargetInfo(ci.getDiagnostics(), to);
+    ci.setTarget(pti);
     ci.createPreprocessor();
 #endif
 
-    clang::HeaderSearch & hs = ci.getPreprocessor().getHeaderSearchInfo() ;
-    clang::HeaderSearchOptions & hso = ci.getHeaderSearchOpts() ;
-    clang::Preprocessor & pp = ci.getPreprocessor() ;
+    // Set all of the defaults to c++
+#if (LIBCLANG_MAJOR > 3) || ((LIBCLANG_MAJOR == 3) && (LIBCLANG_MINOR >= 9))
+    llvm::Triple trip (to.Triple) ;
+    clang::CompilerInvocation::setLangDefaults(ci.getLangOpts(), clang::IK_CXX, trip, ppo) ;
+    // setting the language defaults clears the c++11 flag.
+    ci.getLangOpts().CPlusPlus11 = true ;
+#endif
+    clang::Preprocessor& pp = ci.getPreprocessor();
 
     // Add all of the include directories to the preprocessor
-    HeaderSearchDirs hsd(hs , hso , pp, sim_services_flag) ;
+    HeaderSearchDirs hsd(ci.getPreprocessor().getHeaderSearchInfo(), ci.getHeaderSearchOpts(), pp, sim_services_flag) ;
     hsd.addSearchDirs ( include_dirs ) ;
 
-    // Tell the preprocessor to use its default predefines
-    clang::PreprocessorOptions & ppo = ci.getPreprocessorOpts() ;
-    ppo.UsePredefines = true;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 8)
+#if (LIBCLANG_MAJOR > 3) || ((LIBCLANG_MAJOR == 3) && (LIBCLANG_MINOR >= 8))
     pp.getBuiltinInfo().initializeBuiltins(pp.getIdentifierTable(), pp.getLangOpts());
 #else
     pp.getBuiltinInfo().InitializeBuiltins(pp.getIdentifierTable(), pp.getLangOpts());
@@ -160,12 +138,7 @@ int main( int argc , char * argv[] ) {
 
     // Add our comment saver as a comment handler in the preprocessor
     CommentSaver cs(ci.getSourceManager()) ;
-#if (__clang_major__ == 3) && (__clang_minor__ >= 3)
     pp.addCommentHandler(&cs) ;
-#else
-    pp.AddCommentHandler(&cs) ;
-#endif
-
 
     PrintAttributes pa( attr_version, hsd, cs, ci, force, sim_services_flag) ;
 
@@ -174,9 +147,8 @@ int main( int argc , char * argv[] ) {
 
     // Tell the compiler to use our ICGASTconsumer
     ICGASTConsumer *astConsumer = new ICGASTConsumer(ci, hsd, cs, pa);
-#if (__clang_major__ == 3) && (__clang_minor__ >= 6)
-    std::unique_ptr<clang::ASTConsumer> unique_ast(astConsumer) ;
-    ci.setASTConsumer(std::move(unique_ast));
+#if (LIBCLANG_MAJOR > 3) || ((LIBCLANG_MAJOR == 3) && (LIBCLANG_MINOR >= 6))
+    ci.setASTConsumer(std::move(std::unique_ptr<clang::ASTConsumer>(astConsumer)));
 #else
     ci.setASTConsumer(astConsumer);
 #endif
@@ -195,7 +167,7 @@ int main( int argc , char * argv[] ) {
 
     // Open up the input file and parse it.
     const clang::FileEntry *pFile = ci.getFileManager().getFile(input_file_full_path);
-#if (__clang_major__ == 3) && (__clang_minor__ >= 5)
+#if (LIBCLANG_MAJOR > 3) || ((LIBCLANG_MAJOR == 3) && (LIBCLANG_MINOR >= 5))
     ci.getSourceManager().setMainFileID(ci.getSourceManager().createFileID(pFile, clang::SourceLocation(), clang::SrcMgr::C_User));
 #else
     ci.getSourceManager().createMainFileID(pFile);
diff --git a/trick_source/codegen/Interface_Code_Gen/makefile b/trick_source/codegen/Interface_Code_Gen/makefile
index 02679e1c..63c4e0a9 100644
--- a/trick_source/codegen/Interface_Code_Gen/makefile
+++ b/trick_source/codegen/Interface_Code_Gen/makefile
@@ -2,20 +2,18 @@
 # The config_${HOST_TYPE}.mk file provides LLVM_HOME
 include ${TRICK_HOME}/makefiles/Makefile.common
 
-CC := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --bindir)/clang
-CXX := $(shell $(LLVM_HOME)/bin/$(LLVM_CONFIG) --bindir)/clang++
 CXXFLAGS := -g -I$(shell $(LLVM_HOME)/bin/llvm-config --includedir) -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -fno-rtti
 
-CLANG_MINOR_GTEQ5 := $(shell expr `$(LLVM_HOME)/bin/llvm-config --version | cut -f2 -d. ` \>= 5 )
+CLANG_MAJOR := $(shell $(LLVM_HOME)/bin/llvm-config --version | cut -f1 -d.)
+CLANG_MINOR := $(shell $(LLVM_HOME)/bin/llvm-config --version | cut -f2 -d.)
+CLANG_PATCHLEVEL := $(shell $(LLVM_HOME)/bin/llvm-config --version | cut -f3 -d.)
+# check to see if version is greater than 3.5
+CLANG_MINOR_GTEQ5 := $(shell [ $(CLANG_MAJOR) -gt 3 -o \( $(CLANG_MAJOR) -eq 3 -a $(CLANG_MINOR) -ge 5 \) ] && echo 1)
 
 LLVMLDFLAGS := $(shell $(LLVM_HOME)/bin/llvm-config --ldflags)
 
 OBJ_DIR :=  object_$(TRICK_HOST_CPU)
 
-ifeq ($(IS_CC_CLANG), 0)
-CXXFLAGS += -DGCC_MAJOR=$(GCC_MAJOR) -DGCC_MINOR=$(GCC_MINOR)
-endif
-
 ICG := ICG_$(shell uname -s)_$(shell uname -m)
 
 SOURCES = $(wildcard *.cpp)
@@ -38,30 +36,34 @@ CLANGLIBS = \
     -lclangLex \
     -lclangBasic \
 
+CXXFLAGS += -DLIBCLANG_MAJOR=$(CLANG_MAJOR) -DLIBCLANG_MINOR=$(CLANG_MINOR)
+ifneq ($(CLANG_PATCHLEVEL),)
+CXXFLAGS += -DLIBCLANG_PATCHLEVEL=$(CLANG_PATCHLEVEL)
+endif
+
 ifeq ($(TRICK_HOST_TYPE),Linux)
 CLANGLIBS += $(shell $(LLVM_HOME)/bin/llvm-config --libs)
 ifeq ($(CLANG_MINOR_GTEQ5),1)
-CXXFLAGS += -std=c++11
 # Fedora 21 adds -ledit as a system lib, but it isn't installed, or required.
 CLANGLIBS += $(filter-out -ledit,$(shell $(LLVM_HOME)/bin/llvm-config --system-libs))
 endif
 endif
 
 ifeq ($(TRICK_HOST_TYPE),Darwin)
-CXXFLAGS += -std=c++11
-CLANGLIBS += -lLLVMOption -lLLVMMCParser -lLLVMBitReader -lLLVMMC -lLLVMSupport $(shell $(LLVM_HOME)/bin/llvm-config --system-libs)
+CLANGLIBS += $(shell $(LLVM_HOME)/bin/llvm-config --libs)
+CLANGLIBS += $(shell $(LLVM_HOME)/bin/llvm-config --system-libs)
 CLANGLIBS += -lc++abi
 endif
 
 all: $(ICG)
 
 $(ICG): $(OBJECTS) $(UNITS_CONV_OBJ)
-	$(CXX) -o $@ $(OBJECTS) $(UNITS_CONV_OBJ) $(LLVMLDFLAGS) $(CLANGLIBS)
+	$(CXX) -o $@ $(OBJECTS) $(UNITS_CONV_OBJ) $(CLANGLIBS) $(LLVMLDFLAGS)
 
 # Only FieldDescription.cpp includes the units conversion header.
 $(OBJ_DIR)/FieldDescription.o : CXXFLAGS += $(UNITS_CONV_INCLUDE)
 $(OBJ_DIR)/HeaderSearchDirs.o : CXXFLAGS += -DLLVM_HOME=\"${LLVM_HOME}\"
-$(OBJ_DIR)/main.o : CXXFLAGS += $(UNITS_CONV_INCLUDE)
+$(OBJ_DIR)/main.o : CXXFLAGS += $(UNITS_CONV_INCLUDE) -DTRICK_VERSION=\"${TRICK_VERSION}\"
 
 $(OBJECTS): $(OBJ_DIR)/%.o : %.cpp
 	$(CXX) $(CXXFLAGS) -c $< -o $@