[llvm] [ObjectYAML] Avoid repeated hash lookups (NFC) (PR #111938)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-objectyaml

Author: Kazu Hirata (kazutakahirata)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/111938.diff


1 Files Affected:

- (modified) llvm/lib/ObjectYAML/COFFEmitter.cpp (+3-6) 


``````````diff
diff --git a/llvm/lib/ObjectYAML/COFFEmitter.cpp b/llvm/lib/ObjectYAML/COFFEmitter.cpp
index bb46de4c6f57f4..3811376adebd26 100644
--- a/llvm/lib/ObjectYAML/COFFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/COFFEmitter.cpp
@@ -125,15 +125,12 @@ struct COFFParser {
   }
 
   unsigned getStringIndex(StringRef Str) {
-    StringMap<unsigned>::iterator i = StringTableMap.find(Str);
-    if (i == StringTableMap.end()) {
-      unsigned Index = StringTable.size();
+    auto [It, Inserted] = StringTableMap.try_emplace(Str, StringTable.size());
+    if (Inserted) {
       StringTable.append(Str.begin(), Str.end());
       StringTable.push_back(0);
-      StringTableMap[Str] = Index;
-      return Index;
     }
-    return i->second;
+    return It->second;
   }
 
   COFFYAML::Object &Obj;

``````````

</details>


https://github.com/llvm/llvm-project/pull/111938