diff --git a/apex/apex.cpp b/apex/apex.cpp
index 8d8e99d..501f582 100644
--- a/apex/apex.cpp
+++ b/apex/apex.cpp
@@ -122,20 +122,24 @@ bool APEXPass::runOnModule(Module &M) {
       logPrint("ERROR: exit function is not in symbol table.");
       exit(-1);
     }
-    Function *f = cast<Function>(temp);
-    logPrint("- loaded function: " + f->getGlobalIdentifier());
-    f->dump();
+    Function *exit_fcn = cast<Function>(temp);
+    logPrint("- loaded function: " + exit_fcn->getGlobalIdentifier());
 
     // Create exit call instruction.
-    IRBuilder<> builder = IRBuilder<>(M.getContext());
-    Value *one = ConstantInt::get(Type::getInt32Ty(M.getContext()), 0);
-    CallInst *exit_call = builder.CreateCall(f, one);
-    if (nullptr == exit_call) {
+    Value *exit_arg_val = ConstantInt::get(Type::getInt32Ty(M.getContext()), 9);
+    ArrayRef<Value *> exit_params = makeArrayRef(exit_arg_val);
+    // CallInst::Create build call instruction to @exit_fcn that has @exit_params.
+    // Empty string "" means that the @exit_call_inst will not have return variable.
+    // @exit_call_inst is inserted BEFORE @chosen_instruction.
+    CallInst *exit_call_inst =
+        CallInst::Create(exit_fcn, exit_params, "", chosen_instruction);
+
+    if (nullptr == exit_call_inst) {
       logPrint("ERROR: could not create exit call instruction.");
       exit(-1);
     }
     logPrintFlat("- exit call instruction created: ");
-    exit_call->dump();
+    exit_call_inst->dump();
   }
 
   logPrintUnderline("\nFinal Module Dump:");
diff --git a/build_and_run.sh b/build_and_run.sh
index 67b3c62..5b687e2 100755
--- a/build_and_run.sh
+++ b/build_and_run.sh
@@ -15,11 +15,15 @@
 INPUT_SOURCE="test_dependencies_minimal.c"
 SOURCE_FCN="main"
 TARGET_FCN="y"
+INPUT_LIB="lib.c"
 
 # Generated bytecodes during all stages of processing.
 BYTECODE_FROM_INPUT="bytecode_from_input.bc" # No optimizations.
 BYTECODE_FROM_INPUT_BASIC_OPTS="bytecode_from_input_basic_opts.bc" # Some basic optimizations (see BASIC_OPTS).
 BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX="bytecode_from_input_basic_opts_and_apex.bc" # BASIC_OPTS + APEXPass.
+BYTECODE_FROM_LIB="bytecode_from_lib.bc"
+BYTECODE_LINKED="bytecode_linked.bc"
+LINKED="linked.ll"
 
 # Optimizations that are ran before APEXPass
 BASIC_OPTS="-dce -loop-simplify -simplifycfg"
@@ -62,17 +66,25 @@ clang-format -style=llvm -i apex/*.cpp apex/*.h
 # =============================================================================
 # Compile to bytecode and run basic opts and than our opt =====================
 
-echo "========= Compiling and running APEXPass."
+echo "========= Compiling input."
+
+# compile external libraries
+clang -O0 -c -emit-llvm c-code/${INPUT_LIB} -o build/${BYTECODE_FROM_LIB}
 
 # compile without anything
 clang -O0 -c -emit-llvm c-code/${INPUT_SOURCE} -o build/${BYTECODE_FROM_INPUT}
 
+llvm-link build/${BYTECODE_FROM_LIB} build/${BYTECODE_FROM_INPUT} -S -o=build/${LINKED}
+llvm-as build/${LINKED} -o build/${BYTECODE_LINKED}
+
+echo "========= Running APEXPass."
+
 # run some basic optimizations, so the IR is cleaner
-opt -o build/${BYTECODE_FROM_INPUT_BASIC_OPTS} ${BASIC_OPTS} build/${BYTECODE_FROM_INPUT} > /dev/null
+#opt -o build/${BYTECODE_FROM_INPUT_BASIC_OPTS} ${BASIC_OPTS} build/${BYTECODE_FROM_INPUT} > /dev/null
 
 # run our pass
-#opt -o build/${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX} -load build/apex/libAPEXPass.so -apex -dce -source=${SOURCE_FCN} -target=${TARGET_FCN} < build/${BYTECODE_FROM_INPUT_BASIC_OPTS}  > /dev/null
-opt -o build/${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX} -load build/apex/libAPEXPass.so -apex -source=${SOURCE_FCN} -target=${TARGET_FCN} < build/${BYTECODE_FROM_INPUT_BASIC_OPTS}  > /dev/null
+opt -o build/${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX} -load build/apex/libAPEXPass.so -apex -source=${SOURCE_FCN} -target=${TARGET_FCN} < build/${BYTECODE_LINKED}  > /dev/null
+#opt -o build/${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX} -load build/apex/libAPEXPass.so -apex -source=${SOURCE_FCN} -target=${TARGET_FCN} < build/${BYTECODE_FROM_INPUT_BASIC_OPTS}  > /dev/null
 
 # ==============================================================================
 # Generate callgraphs before and after =========================================
@@ -89,9 +101,9 @@ opt -dot-callgraph ../${BYTECODE_FROM_INPUT} > /dev/null
 mv callgraph.dot callgraph_no_opt.dot
 dot callgraph_no_opt.dot -Tsvg -O
 
-opt -dot-callgraph ../${BYTECODE_FROM_INPUT_BASIC_OPTS} > /dev/null
-mv callgraph.dot callgraph_default_opt.dot
-dot callgraph_default_opt.dot -Tsvg -O
+#opt -dot-callgraph ../${BYTECODE_FROM_INPUT_BASIC_OPTS} > /dev/null
+#mv callgraph.dot callgraph_default_opt.dot
+#dot callgraph_default_opt.dot -Tsvg -O
 
 opt -dot-callgraph ../${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX} > /dev/null
 mv callgraph.dot callgraph_apex_opt.dot
@@ -138,8 +150,9 @@ cd ../..
 echo "========= Disassembling llvm bytecode."
 
 llvm-dis build/${BYTECODE_FROM_INPUT}
-llvm-dis build/${BYTECODE_FROM_INPUT_BASIC_OPTS}
+#llvm-dis build/${BYTECODE_FROM_INPUT_BASIC_OPTS}
 llvm-dis build/${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX}
+llvm-dis build/${BYTECODE_FROM_LIB}
 
 
 # ==============================================================================
@@ -150,8 +163,8 @@ echo "========= Running ${BYTECODE_FROM_INPUT}"
 lli build/${BYTECODE_FROM_INPUT}
 
 # run bytecode after basic opts
-echo "========= Running ${BYTECODE_FROM_INPUT_BASIC_OPTS}"
-lli build/${BYTECODE_FROM_INPUT_BASIC_OPTS}
+#echo "========= Running ${BYTECODE_FROM_INPUT_BASIC_OPTS}"
+#lli build/${BYTECODE_FROM_INPUT_BASIC_OPTS}
 
 # run pass and execute modified bytecode
 echo "========= Running ${BYTECODE_FROM_INPUT_BASIC_OPTS_AND_APEX}"
diff --git a/c-code/lib.c b/c-code/lib.c
new file mode 100644
index 0000000..6ad63be
--- /dev/null
+++ b/c-code/lib.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+void print()
+{
+    printf("PRINT() from LIB\n");
+}
diff --git a/c-code/test_dependencies_minimal.c b/c-code/test_dependencies_minimal.c
index ea09652..da086af 100644
--- a/c-code/test_dependencies_minimal.c
+++ b/c-code/test_dependencies_minimal.c
@@ -1,30 +1,36 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-void test(void) {
-  return;
-}
 
 int x(void) {
+//  printf("x: in\n");
+//  printf("x: out\n");
   return 10;
 }
 
 int y(int n) {
+  printf("y: in\n");
   int tmp = n+n;
+  printf("y: out\n");
   return tmp;
 }
 
 int z(void) {
+//  printf("z: in\n");
   int tmp = 1;
+//  printf("z: out\n");
   return tmp;
 }
 
 int n(void) {
+  printf("n: in\n");
   int y_ret = y(10);
+  printf("n: out\n");
   return y_ret;
 }
 
 int main(void) {
+  printf("main: in\n");
   int x_ret = x();
 
   int y_ret = y(x_ret);
@@ -36,5 +42,6 @@ int main(void) {
   int n_ret = n();
   int n_store = n_ret;
 
+  printf("main: out\n");
   return 0;
 }