[llvm] [llvm][metadata][NFC] Minimize local variable scopes (PR #68438)

[Paul Kirth via llvm-commits]

https://github.com/ilovepi created https://github.com/llvm/llvm-project/pull/68438

Don't eagerly construct the MDBuilder until it is used, and reduce the scope of local variables.

>From 1635382d4ee86e1c7b4b9581380ab6965876a6d0 Mon Sep 17 00:00:00 2001
From: Paul Kirth <paulkirth at google.com>
Date: Fri, 6 Oct 2023 11:18:44 -0700
Subject: [PATCH] [llvm][metadata][NFC] Minimize local variable scopes

Don't eagerly construct the MDBuilder until it is used, and reduce the
scope of local variables.
---
 llvm/lib/IR/Metadata.cpp | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/llvm/lib/IR/Metadata.cpp b/llvm/lib/IR/Metadata.cpp
index c153ffb71a73bba..f6eed9e777a8c4b 100644
--- a/llvm/lib/IR/Metadata.cpp
+++ b/llvm/lib/IR/Metadata.cpp
@@ -1542,13 +1542,10 @@ void Instruction::setMetadata(unsigned KindID, MDNode *Node) {
 }
 
 void Instruction::addAnnotationMetadata(SmallVector<StringRef> Annotations) {
-  SmallSetVector<StringRef, 2> AnnotationsSet(Annotations.begin(),
-                                              Annotations.end());
-  MDBuilder MDB(getContext());
-
-  auto *Existing = getMetadata(LLVMContext::MD_annotation);
   SmallVector<Metadata *, 4> Names;
-  if (Existing) {
+  if (auto *Existing = getMetadata(LLVMContext::MD_annotation)) {
+    SmallSetVector<StringRef, 2> AnnotationsSet(Annotations.begin(),
+                                                Annotations.end());
     auto *Tuple = cast<MDTuple>(Existing);
     for (auto &N : Tuple->operands()) {
       if (isa<MDString>(N.get())) {
@@ -1564,6 +1561,7 @@ void Instruction::addAnnotationMetadata(SmallVector<StringRef> Annotations) {
     }
   }
 
+  MDBuilder MDB(getContext());
   SmallVector<Metadata *> MDAnnotationStrings;
   for (StringRef Annotation : Annotations)
     MDAnnotationStrings.push_back(MDB.createString(Annotation));
@@ -1574,11 +1572,8 @@ void Instruction::addAnnotationMetadata(SmallVector<StringRef> Annotations) {
 }
 
 void Instruction::addAnnotationMetadata(StringRef Name) {
-  MDBuilder MDB(getContext());
-
-  auto *Existing = getMetadata(LLVMContext::MD_annotation);
   SmallVector<Metadata *, 4> Names;
-  if (Existing) {
+  if (auto *Existing = getMetadata(LLVMContext::MD_annotation)) {
     auto *Tuple = cast<MDTuple>(Existing);
     for (auto &N : Tuple->operands()) {
       if (isa<MDString>(N.get()) &&
@@ -1588,6 +1583,7 @@ void Instruction::addAnnotationMetadata(StringRef Name) {
     }
   }
 
+  MDBuilder MDB(getContext());
   Names.push_back(MDB.createString(Name));
   MDNode *MD = MDTuple::get(getContext(), Names);
   setMetadata(LLVMContext::MD_annotation, MD);