[llvm-branch-commits] [llvm] [BOLT] Name similarity function matching (PR #95884)

[Maksim Panchenko via llvm-branch-commits]

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@@ -415,11 +423,116 @@ Error YAMLProfileReader::readProfile(BinaryContext &BC) {
     if (!YamlBF.Used && BF && !ProfiledFunctions.count(BF))
       matchProfileToFunction(YamlBF, *BF);
 
+  // Uses name similarity to match functions that were not matched by name.
+  uint64_t MatchedWithNameSimilarity = 0;
+
+  if (opts::NameSimilarityFunctionMatchingThreshold > 0) {
+    ItaniumPartialDemangler ItaniumPartialDemangler;
+
+    auto DemangleName = [&](std::string &FunctionName) {
+      StringRef RestoredName = NameResolver::restore(FunctionName);
+      return demangle(RestoredName);
+    };
+
+    auto DeriveNameSpace = [&](std::string &DemangledName) {
+      if (ItaniumPartialDemangler.partialDemangle(DemangledName.c_str()))
+        return std::string("");
+      std::vector<char> Buffer(DemangledName.begin(), DemangledName.end());
+      size_t BufferSize = Buffer.size();
+      char *NameSpace = ItaniumPartialDemangler.getFunctionDeclContextName(
+          &Buffer[0], &BufferSize);
+      return NameSpace ? std::string(NameSpace) : std::string("");
+    };
+
+    // Preprocessing YamlBFs to minimize the number of BFs to process.
+    std::unordered_map<std::string, std::set<uint32_t>>
+      NamespaceToProfiledBFSizes;
+    NamespaceToProfiledBFSizes.reserve(YamlBP.Functions.size());
+    std::vector<std::string> ProfileBFDemangledNames;
+    ProfileBFDemangledNames.reserve(YamlBP.Functions.size());
+    std::vector<std::string> ProfiledBFNamespaces;
+    ProfiledBFNamespaces.reserve(YamlBP.Functions.size());
+
+    for (auto &YamlBF : YamlBP.Functions) {
+      std::string YamlBFDemangledName = DemangleName(YamlBF.Name);
+      ProfileBFDemangledNames.push_back(YamlBFDemangledName);
+      std::string YamlBFNamespace = DeriveNameSpace(YamlBFDemangledName);
+      ProfiledBFNamespaces.push_back(YamlBFNamespace);
+      NamespaceToProfiledBFSizes[YamlBFNamespace].insert(YamlBF.NumBasicBlocks);
+    }
+
+    std::unordered_map<std::string, std::vector<BinaryFunction *>>
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maksfb wrote:

Same for `StringMap`.

https://github.com/llvm/llvm-project/pull/95884