[clang] [clang] Improve move-assign and move-constructor for NestedNameSpecif… (PR #180484)

[via cfe-commits]

https://github.com/serge-sans-paille created https://github.com/llvm/llvm-project/pull/180484

…ierLocBuilder

This avoids a deepcopy of the manually managed underlying Buffer.

This is a follow-up to #180482.

>From 66129949425ef5816bb90a77b835e2795bcaa253 Mon Sep 17 00:00:00 2001
From: serge-sans-paille <sguelton at mozilla.com>
Date: Mon, 9 Feb 2026 09:23:18 +0100
Subject: [PATCH] [clang] Improve move-assign and move-constructor for
 NestedNameSpecifierLocBuilder

This avoids a deepcopy of the manually managed underlying Buffer.

This is a follow-up to #180482.
---
 .../clang/AST/NestedNameSpecifierBase.h       |  4 +++
 clang/lib/AST/NestedNameSpecifier.cpp         | 26 +++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/clang/include/clang/AST/NestedNameSpecifierBase.h b/clang/include/clang/AST/NestedNameSpecifierBase.h
index 8f4bbe97f6e9a..3330fed58ba79 100644
--- a/clang/include/clang/AST/NestedNameSpecifierBase.h
+++ b/clang/include/clang/AST/NestedNameSpecifierBase.h
@@ -450,10 +450,14 @@ class NestedNameSpecifierLocBuilder {
 public:
   NestedNameSpecifierLocBuilder() = default;
   NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other);
+  NestedNameSpecifierLocBuilder(NestedNameSpecifierLocBuilder &&Other);
 
   NestedNameSpecifierLocBuilder &
   operator=(const NestedNameSpecifierLocBuilder &Other);
 
+  NestedNameSpecifierLocBuilder &
+  operator=(NestedNameSpecifierLocBuilder &&Other);
+
   ~NestedNameSpecifierLocBuilder() {
     if (BufferCapacity)
       free(Buffer);
diff --git a/clang/lib/AST/NestedNameSpecifier.cpp b/clang/lib/AST/NestedNameSpecifier.cpp
index c6af91f5c0083..5668900e6733c 100644
--- a/clang/lib/AST/NestedNameSpecifier.cpp
+++ b/clang/lib/AST/NestedNameSpecifier.cpp
@@ -208,6 +208,14 @@ NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other)
          BufferCapacity);
 }
 
+NestedNameSpecifierLocBuilder::NestedNameSpecifierLocBuilder(
+    NestedNameSpecifierLocBuilder &&Other)
+    : Representation(std::move(Other.Representation)), Buffer(Other.Buffer),
+      BufferSize(Other.BufferSize), BufferCapacity(Other.BufferCapacity) {
+  Other.buffer = nullptr;
+  Other.BufferCapacity = Other.size = 0;
+}
+
 NestedNameSpecifierLocBuilder &
 NestedNameSpecifierLocBuilder::
 operator=(const NestedNameSpecifierLocBuilder &Other) {
@@ -247,6 +255,24 @@ operator=(const NestedNameSpecifierLocBuilder &Other) {
   return *this;
 }
 
+NestedNameSpecifierLocBuilder &NestedNameSpecifierLocBuilder::operator=(
+    NestedNameSpecifierLocBuilder &&Other) {
+  Representation = std::move(Other.Representation);
+
+  // Free our storage, if we have any.
+  if (BufferCapacity) {
+    free(Buffer);
+  }
+  Buffer = Other.Buffer;
+  BufferSize = Other.BufferSize;
+  BufferCapacity = Other.BufferCapacity;
+
+  Other.Buffer = nullptr;
+  Other.BufferSize = Other.BufferCapacity = 0;
+
+  return *this;
+}
+
 void NestedNameSpecifierLocBuilder::Make(ASTContext &Context, TypeLoc TL,
                                          SourceLocation ColonColonLoc) {
   assert(!Representation);