Avoid copies of std::strings and APInt/APFloats where we only read from it

As suggested by clang-tidy's performance-unnecessary-copy-initialization.
This can easily hit lifetime issues, so I audited every change and ran the
tests under asan, which came back clean.

llvm-svn: 272126

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/tools/lli/lli.cpp b/llvm/tools/lli/lli.cpp
index 28232478217..868fc16cd7f 100644
--- a/llvm/tools/lli/lli.cpp
+++ b/llvm/tools/lli/lli.cpp
@@ -254,7 +254,7 @@ public:
   ~LLIObjectCache() override {}
 
   void notifyObjectCompiled(const Module *M, MemoryBufferRef Obj) override {
-    const std::string ModuleID = M->getModuleIdentifier();
+    const std::string &ModuleID = M->getModuleIdentifier();
     std::string CacheName;
     if (!getCacheFilename(ModuleID, CacheName))
       return;
@@ -269,7 +269,7 @@ public:
   }
 
   std::unique_ptr<MemoryBuffer> getObject(const Module* M) override {
-    const std::string ModuleID = M->getModuleIdentifier();
+    const std::string &ModuleID = M->getModuleIdentifier();
     std::string CacheName;
     if (!getCacheFilename(ModuleID, CacheName))
       return nullptr;