Add a SafeMap equivalent to std::map but without the error-prone operator[].

Change-Id: Iae5ba2091c55a34dbd1005cf3d25fce2a8d5c1f9
diff --git a/src/compiler/codegen/CodegenUtil.cc b/src/compiler/codegen/CodegenUtil.cc
index 00e78ec..777cf57 100644
--- a/src/compiler/codegen/CodegenUtil.cc
+++ b/src/compiler/codegen/CodegenUtil.cc
@@ -857,7 +857,7 @@
  */
 LIR* insertCaseLabel(CompilationUnit* cUnit, int vaddr, int keyVal)
 {
-    std::map<unsigned int, LIR*>::iterator it;
+    SafeMap<unsigned int, LIR*>::iterator it;
     it = cUnit->boundaryMap.find(vaddr);
     if (it == cUnit->boundaryMap.end()) {
         LOG(FATAL) << "Error: didn't find vaddr 0x" << std::hex << vaddr;