Pass some DataLayout arguments by const-ref

Avoid unnecessary copies, reported by MSVC static analyzer.

llvm/lib/Transforms/Coroutines/CoroFrame.cpp

@@ -435,7 +435,7 @@ private:
   DenseMap<Value*, unsigned> FieldIndexByKey;
 
 public:
-  FrameTypeBuilder(LLVMContext &Context, DataLayout const &DL,
+  FrameTypeBuilder(LLVMContext &Context, const DataLayout &DL,
                    Optional<Align> MaxFrameAlignment)
       : DL(DL), Context(Context), MaxFrameAlignment(MaxFrameAlignment) {}
 
@@ -840,8 +840,9 @@ static StringRef solveTypeName(Type *Ty) {
   return "UnknownType";
 }
 
-static DIType *solveDIType(DIBuilder &Builder, Type *Ty, DataLayout &Layout,
-                           DIScope *Scope, unsigned LineNum,
+static DIType *solveDIType(DIBuilder &Builder, Type *Ty,
+                           const DataLayout &Layout, DIScope *Scope,
+                           unsigned LineNum,
                            DenseMap<Type *, DIType *> &DITypeCache) {
   if (DIType *DT = DITypeCache.lookup(Ty))
     return DT;

llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp

@@ -67,7 +67,8 @@ bool isUsefullToPreserve(Attribute::AttrKind Kind) {
 
 /// This function will try to transform the given knowledge into a more
 /// canonical one. the canonical knowledge maybe the given one.
-RetainedKnowledge canonicalizedKnowledge(RetainedKnowledge RK, DataLayout DL) {
+RetainedKnowledge canonicalizedKnowledge(RetainedKnowledge RK,
+                                         const DataLayout &DL) {
   switch (RK.AttrKind) {
   default:
     return RK;

llvm/tools/llvm-exegesis/lib/Assembler.cpp

@@ -153,7 +153,7 @@ ArrayRef<unsigned> FunctionFiller::getRegistersSetUp() const {
 }
 
 static std::unique_ptr<Module>
-createModule(const std::unique_ptr<LLVMContext> &Context, const DataLayout DL) {
+createModule(const std::unique_ptr<LLVMContext> &Context, const DataLayout &DL) {
   auto Mod = std::make_unique<Module>(ModuleID, *Context);
   Mod->setDataLayout(DL);
   return Mod;