Prevent copy of AttrBuilder

[serge-sans-paille]

Summary

It's a relatively heavy data structure, make sure it's not copied.

[nikic]

LG

llvm/include/llvm/IR/Attributes.h

947

nit: const AttrBuilder & would be more typical.

llvm/lib/IR/Verifier.cpp

3317

nit: Extra space after &.

llvm/include/llvm/IR/Attributes.h

class AttrBuilder {
   std::array<uint64_t, Attribute::NumIntAttrKinds> IntAttrs = {};
   std::array<Type *, Attribute::NumTypeAttrKinds> TypeAttrs = {};
 
   Optional<unsigned> kindToIntIndex(Attribute::AttrKind Kind) const;
   Optional<unsigned> kindToTypeIndex(Attribute::AttrKind Kind) const;
 
 public:
   AttrBuilder() = default;
+  AttrBuilder(const AttrBuilder &) = delete;
+  AttrBuilder(AttrBuilder &&) = default;
 
   AttrBuilder(const Attribute &A) {
     addAttribute(A);
   }
 
   AttrBuilder(AttributeList AS, unsigned Idx);
   AttrBuilder(AttributeSet AS);
 

llvm/lib/IR/Verifier.cpp

#include "llvm/IR/Metadata.def"
   void visitCatchReturnInst(CatchReturnInst &CatchReturn);
   void visitCleanupPadInst(CleanupPadInst &CPI);
   void visitFuncletPadInst(FuncletPadInst &FPI);
   void visitCatchSwitchInst(CatchSwitchInst &CatchSwitch);
   void visitCleanupReturnInst(CleanupReturnInst &CRI);
 
   void verifySwiftErrorCall(CallBase &Call, const Value *SwiftErrorVal);
   void verifySwiftErrorValue(const Value *SwiftErrorVal);
-  void verifyTailCCMustTailAttrs(AttrBuilder Attrs, StringRef Context);
+  void verifyTailCCMustTailAttrs(const AttrBuilder &Attrs, StringRef Context);
   void verifyMustTailCall(CallInst &CI);
   bool verifyAttributeCount(AttributeList Attrs, unsigned Params);
   void verifyAttributeTypes(AttributeSet Attrs, const Value *V);
   void verifyParameterAttrs(AttributeSet Attrs, Type *Ty, const Value *V);
   void checkUnsignedBaseTenFuncAttr(AttributeList Attrs, StringRef Attr,
                                     const Value *V);
   void verifyFunctionAttrs(FunctionType *FT, AttributeList Attrs,
                            const Value *V, bool IsIntrinsic);
if (Call.getFunction()->getSubprogram() && Call.getCalledFunction() &&
     AssertDI(Call.getDebugLoc(),
              "inlinable function call in a function with "
              "debug info must have a !dbg location",
              Call);
 
   visitInstruction(Call);
 }
 
-void Verifier::verifyTailCCMustTailAttrs(AttrBuilder Attrs,
+void Verifier::verifyTailCCMustTailAttrs(const AttrBuilder &Attrs,
                                          StringRef Context) {
   Assert(!Attrs.contains(Attribute::InAlloca),
          Twine("inalloca attribute not allowed in ") + Context);
   Assert(!Attrs.contains(Attribute::InReg),
          Twine("inreg attribute not allowed in ") + Context);
   Assert(!Attrs.contains(Attribute::SwiftError),
          Twine("swifterror attribute not allowed in ") + Context);
   Assert(!Attrs.contains(Attribute::Preallocated),