[NFC][clang-tools-extra]Replace find/insert with try_emplace

[prehistoric-penguin]

Summary

The change will save us one find call in map, which is more efficient and
more clear.

[avogelsgesang]

clang-tools-extra/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp

140

Previously, we had an additional check It->second != SourceTU here. I don't understand what this check was doing, but this does not seem to be a pure refactoring.

If this is still an NFC change, please update the commit message to explain why this condition was unneeded

[prehistoric-penguin]

Fix per comment

[prehistoric-penguin]

Update commit message

[prehistoric-penguin]

clang-tools-extra/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp

140

Thanks! I have reviewed the change and fixed it, now the logic is aligned

[prehistoric-penguin]

Format change

[avogelsgesang]

The change itself looks good.

Please look into the CI failures before landing this.

[prehistoric-penguin]

Rebase

[prehistoric-penguin]

Rebase

[prehistoric-penguin]

CI failed since LLVM is still using c++14 to build

CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/clang++ -DBUILD_EXAMPLES -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/var/lib/buildkite-agent/builds/llvm-project/build/tools/clang/tools/extra/clang-apply-replacements -I/var/lib/buildkite-agent/builds/llvm-project/clang-tools-extra/clang-apply-replacements -I/var/lib/buildkite-agent/builds/llvm-project/clang/include -I/var/lib/buildkite-agent/builds/llvm-project/build/tools/clang/include -I/var/lib/buildkite-agent/builds/llvm-project/build/include -I/var/lib/buildkite-agent/builds/llvm-project/llvm/include -I/var/lib/buildkite-agent/builds/llvm-project/clang-tools-extra/clang-apply-replacements/include -gmlt -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -fdiagnostics-color -ffunction-sections -fdata-sections -fno-common -Woverloaded-virtual -Wno-nested-anon-types -O3 -DNDEBUG  -fno-exceptions -fno-rtti -UNDEBUG -std=c++14 -MD -MT tools/clang/tools/extra/clang-apply-replacements/CMakeFiles/obj.clangApplyReplacements.dir/lib/Tooling/ApplyReplacements.cpp.o -MF tools/clang/tools/extra/clang-apply-replacements/CMakeFiles/obj.clangApplyReplacements.dir/lib/Tooling/ApplyReplacements.cpp.o.d -o tools/clang/tools/extra/clang-apply-replacements/CMakeFiles/obj.clangApplyReplacements.dir/lib/Tooling/ApplyReplacements.cpp.o -c /var/lib/buildkite-agent/builds/llvm-project/clang-tools-extra/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp

/var/lib/buildkite-agent/builds/llvm-project/clang-tools-extra/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp:171:35: error: no member named 'try_emplace' in 'std::map<clang::tooling::Replacement, const clang::tooling::TranslationUnitDiagnostics *>'

        auto InsertPos = Replaces.try_emplace(R, SourceTU);

We may close this temporarily and reopen it after the c++17 flag is ready.

Or we may switch the type of DiagReplacements from llvm::DenseMap<const FileEntry *,std::map<tooling::Replacement, const tooling::TranslationUnitDiagnostics *>> to llvm::DenseMap<const FileEntry *,llvm::DenseMap<tooling::Replacement, const tooling::TranslationUnitDiagnostics *>>

clang-tools-extra/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp

auto AddToGroup = [&](const tooling::Replacement &R,
     // Use the file manager to deduplicate paths. FileEntries are
     // automatically canonicalized.
     auto PrevWorkingDir = SM.getFileManager().getFileSystemOpts().WorkingDir;
     if (BuildDir)
       SM.getFileManager().getFileSystemOpts().WorkingDir = std::move(*BuildDir);
     if (auto Entry = SM.getFileManager().getFile(R.getFilePath())) {
       if (SourceTU) {
         auto &Replaces = DiagReplacements[*Entry];
-        auto It = Replaces.find(R);
-        if (It == Replaces.end())
-          Replaces.emplace(R, SourceTU);
-        else if (It->second != SourceTU)
-          // This replacement is a duplicate of one suggested by another TU.
+        auto InsertPos = Replaces.try_emplace(R, SourceTU);
+        if (!InsertPos.second && InsertPos.first->second != SourceTU) {
           return;
         }
+      }
       GroupedReplacements[*Entry].push_back(R);
     } else if (Warned.insert(R.getFilePath()).second) {
       errs() << "Described file '" << R.getFilePath()
              << "' doesn't exist. Ignoring...\n";
     }
     SM.getFileManager().getFileSystemOpts().WorkingDir = PrevWorkingDir;
   };