[NFC]add mov constructor to DIEValue

[barannikov88]

llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h

38

std::move is redundant here, the expression is already xvalue.
The same is true in other places.

[barannikov88]

llvm/include/llvm/CodeGen/DIE.h

466

It is no more efficient than the copy constructor.
Why do you need it?

[XinWang10]

llvm/include/llvm/CodeGen/DIE.h

466

Because I think DIEValue could maintain dynamic memory, copy constructor here need to first construct a temporary one and assign to this then destruct it self, couldn't move here be more efficient?

[XinWang10]

llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h

38

Oh, sorry, my mistake, so you are right, we don't need move construct

[XinWang10]

Thanks for your remind

llvm/include/llvm/CodeGen/DIE.h

 
 public:
   DIEValue() = default;
 
   DIEValue(const DIEValue &X) : Ty(X.Ty), Attribute(X.Attribute), Form(X.Form) {
     copyVal(X);
   }
 
+  DIEValue(DIEValue &&X) : Ty(X.Ty), Attribute(X.Attribute), Form(X.Form) {
+    copyVal(X);
+    X.Ty = isNone;
+  }
+
   DIEValue &operator=(const DIEValue &X) {
     if (this == &X)
       return *this;
     destroyVal();
     Ty = X.Ty;
     Attribute = X.Attribute;
     Form = X.Form;
     copyVal(X);

llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h

struct PatchLocation {
 
   PatchLocation() = default;
   PatchLocation(DIE::value_iterator I) : I(I) {}
 
   void set(uint64_t New) const {
     assert(I);
     const auto &Old = *I;
     assert(Old.getType() == DIEValue::isInteger);
-    *I = DIEValue(Old.getAttribute(), Old.getForm(), DIEInteger(New));
+    *I =
+        std::move(DIEValue(Old.getAttribute(), Old.getForm(), DIEInteger(New)));
   }
 
   uint64_t get() const {
     assert(I);
     return I->getDIEInteger().getValue();
   }
 };
 

llvm/lib/DWARFLinker/DWARFLinker.cpp

unsigned DWARFLinker::DIECloner::cloneBlockAttribute(
   } else {
     Block = new (DIEAlloc) DIEBlock;
     Linker.DIEBlocks.push_back(Block);
   }
   Attr = Loc ? static_cast<DIEValueList *>(Loc)
              : static_cast<DIEValueList *>(Block);
 
   if (Loc)
-    Value = DIEValue(dwarf::Attribute(AttrSpec.Attr),
-                     dwarf::Form(AttrSpec.Form), Loc);
+    Value = std::move(DIEValue(dwarf::Attribute(AttrSpec.Attr),
+                               dwarf::Form(AttrSpec.Form), Loc));
   else
-    Value = DIEValue(dwarf::Attribute(AttrSpec.Attr),
-                     dwarf::Form(AttrSpec.Form), Block);
+    Value = std::move(DIEValue(dwarf::Attribute(AttrSpec.Attr),
+                               dwarf::Form(AttrSpec.Form), Block));
 
   // If the block is a DWARF Expression, clone it into the temporary
   // buffer using cloneExpression(), otherwise copy the data directly.
   SmallVector<uint8_t, 32> Buffer;
   ArrayRef<uint8_t> Bytes = *Val.getAsBlock();
   if (DWARFAttribute::mayHaveLocationExpr(AttrSpec.Attr) &&
       (Val.isFormClass(DWARFFormValue::FC_Block) ||
        Val.isFormClass(DWARFFormValue::FC_Exprloc))) {
static void insertLineSequence(std::vector<DWARFDebugLine::Row> &Seq,
   }
 
   Seq.clear();
 }
 
 static void patchStmtList(DIE &Die, DIEInteger Offset) {
   for (auto &V : Die.values())
     if (V.getAttribute() == dwarf::DW_AT_stmt_list) {
-      V = DIEValue(V.getAttribute(), V.getForm(), Offset);
+      V = std::move(DIEValue(V.getAttribute(), V.getForm(), Offset));
       return;
     }
 
   llvm_unreachable("Didn't find DW_AT_stmt_list in cloned DIE!");
 }
 
 /// Extract the line table for \p Unit from \p OrigDwarf, and
 /// recreate a relocated version of these for the address ranges that

llvm/lib/DWARFLinker/DWARFStreamer.cpp

for (const DWARFDebugMacro::MacroList &List : MacroTable->MacroLists) {
     if (OutputUnitDIE == nullptr)
       continue;
 
     // Update macro attribute of cloned compile unit with the proper offset to
     // the macro table.
     bool hasDWARFv5Header = false;
     for (auto &V : OutputUnitDIE->values()) {
       if (V.getAttribute() == dwarf::DW_AT_macro_info) {
-        V = DIEValue(V.getAttribute(), V.getForm(), DIEInteger(OutOffset));
+        V = std::move(
+            DIEValue(V.getAttribute(), V.getForm(), DIEInteger(OutOffset)));
         break;
       } else if (V.getAttribute() == dwarf::DW_AT_macros) {
         hasDWARFv5Header = true;
-        V = DIEValue(V.getAttribute(), V.getForm(), DIEInteger(OutOffset));
+        V = std::move(
+            DIEValue(V.getAttribute(), V.getForm(), DIEInteger(OutOffset)));
         break;
       }
     }
 
     // Write DWARFv5 header.
     if (hasDWARFv5Header) {
       // Write header version.
       MS->emitIntValue(List.Header.Version, sizeof(List.Header.Version));