Add const to some methods and change TestMergedProgram to return the merged
module and take a const BugDriver.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109951 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/bugpoint/ExecutionDriver.cpp b/tools/bugpoint/ExecutionDriver.cpp
index 01dd379..28f61c8 100644
--- a/tools/bugpoint/ExecutionDriver.cpp
+++ b/tools/bugpoint/ExecutionDriver.cpp
@@ -325,7 +325,7 @@
                                       std::string BitcodeFile,
                                       const std::string &SharedObj,
                                       AbstractInterpreter *AI,
-                                      std::string *Error) {
+                                      std::string *Error) const {
   if (AI == 0) AI = Interpreter;
   assert(AI && "Interpreter should have been created already!");
   bool CreatedBitcode = false;
@@ -402,7 +402,7 @@
 ///
 std::string BugDriver::executeProgramSafely(const Module *Program,
                                             std::string OutputFile,
-                                            std::string *Error) {
+                                            std::string *Error) const {
   return executeProgram(Program, OutputFile, "", "", SafeInterpreter, Error);
 }
 
@@ -466,7 +466,7 @@
                             const std::string &BitcodeFile,
                             const std::string &SharedObject,
                             bool RemoveBitcode,
-                            std::string *ErrMsg) {
+                            std::string *ErrMsg) const {
   // Execute the program, generating an output file...
   sys::Path Output(executeProgram(Program, "", BitcodeFile, SharedObject, 0,
                                   ErrMsg));