Make out arguments non-reference types.

Also, tidy some portable related code.

Change-Id: I67c8aa52eef8b556ca117ecda1b1e75465ba06a5
diff --git a/compiler/dex/compiler_ir.h b/compiler/dex/compiler_ir.h
index 8447d23..b9a26d6 100644
--- a/compiler/dex/compiler_ir.h
+++ b/compiler/dex/compiler_ir.h
@@ -64,7 +64,7 @@
   const CompilerBackend* compiler_backend;
   InstructionSet instruction_set;
 
-  const InstructionSetFeatures& GetInstructionSetFeatures() {
+  InstructionSetFeatures GetInstructionSetFeatures() {
     return compiler_driver->GetInstructionSetFeatures();
   }
   // TODO: much of this info available elsewhere.  Go to the original source?
diff --git a/compiler/dex/frontend.cc b/compiler/dex/frontend.cc
index 6800f7b..2619258 100644
--- a/compiler/dex/frontend.cc
+++ b/compiler/dex/frontend.cc
@@ -128,7 +128,7 @@
   }
 }
 
-static CompiledMethod* CompileMethod(CompilerDriver& compiler,
+static CompiledMethod* CompileMethod(CompilerDriver& driver,
                                      CompilerBackend* compiler_backend,
                                      const DexFile::CodeItem* code_item,
                                      uint32_t access_flags, InvokeType invoke_type,
@@ -143,11 +143,11 @@
   }
 
   ClassLinker* class_linker = Runtime::Current()->GetClassLinker();
-  CompilationUnit cu(&compiler.GetArenaPool());
+  CompilationUnit cu(driver.GetArenaPool());
 
-  cu.compiler_driver = &compiler;
+  cu.compiler_driver = &driver;
   cu.class_linker = class_linker;
-  cu.instruction_set = compiler.GetInstructionSet();
+  cu.instruction_set = driver.GetInstructionSet();
   cu.compiler_backend = compiler_backend;
   DCHECK((cu.instruction_set == kThumb2) ||
          (cu.instruction_set == kX86) ||
@@ -216,8 +216,8 @@
   }
 
   /* Create the pass driver and launch it */
-  PassDriver driver(&cu);
-  driver.Launch();
+  PassDriver pass_driver(&cu);
+  pass_driver.Launch();
 
   if (cu.enable_debug & (1 << kDebugDumpCheckStats)) {
     cu.mir_graph->DumpCheckStats();
@@ -257,9 +257,9 @@
   }
 
   cu.EndTiming();
-  compiler.GetTimingsLogger().Start();
-  compiler.GetTimingsLogger().AddLogger(cu.timings);
-  compiler.GetTimingsLogger().End();
+  driver.GetTimingsLogger()->Start();
+  driver.GetTimingsLogger()->AddLogger(cu.timings);
+  driver.GetTimingsLogger()->End();
   return result;
 }