[clang-tools-extra] [clang-include-fixer] Use heterogenous lookups with std::map (NFC) (PR #115113)

[Kazu Hirata via cfe-commits]

https://github.com/kazutakahirata created https://github.com/llvm/llvm-project/pull/115113

Heterogenous lookups allow us to call find with StringRef, avoiding a
temporary heap allocation of std::string.


>From d83d2c1478982e3c09ef7c7e80880e3f874c69eb Mon Sep 17 00:00:00 2001
From: Kazu Hirata <kazu at google.com>
Date: Tue, 5 Nov 2024 10:11:22 -0800
Subject: [PATCH] [clang-include-fixer] Use heterogenous lookups with std::map
 (NFC)

Heterogenous lookups allow us to call find with StringRef, avoiding a
temporary heap allocation of std::string.
---
 clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.cpp | 2 +-
 clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.h   | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.cpp b/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.cpp
index 93b534d26f2ce3..6d272af7436923 100644
--- a/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.cpp
+++ b/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.cpp
@@ -21,7 +21,7 @@ InMemorySymbolIndex::InMemorySymbolIndex(
 
 std::vector<SymbolAndSignals>
 InMemorySymbolIndex::search(llvm::StringRef Identifier) {
-  auto I = LookupTable.find(std::string(Identifier));
+  auto I = LookupTable.find(Identifier);
   if (I != LookupTable.end())
     return I->second;
   return {};
diff --git a/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.h b/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.h
index bea8be91a43c75..c91a7a3a0a10e4 100644
--- a/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.h
+++ b/clang-tools-extra/clang-include-fixer/InMemorySymbolIndex.h
@@ -27,7 +27,8 @@ class InMemorySymbolIndex : public SymbolIndex {
   search(llvm::StringRef Identifier) override;
 
 private:
-  std::map<std::string, std::vector<find_all_symbols::SymbolAndSignals>>
+  std::map<std::string, std::vector<find_all_symbols::SymbolAndSignals>,
+           std::less<>>
       LookupTable;
 };