[NFC][LTO] Move GUID calculation into CfiFunctionIndex (#130370)

Preparation for CFI Index refactoring,
which will fix O(N^2) in ThinLTO indexing.

Author: vitalybuka

llvm/include/llvm/IR/ModuleSummaryIndex.h

@@ -23,6 +23,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/iterator_range.h"
 #include "llvm/IR/ConstantRange.h"
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Module.h"
@@ -1293,8 +1294,26 @@ class CfiFunctionIndex {
   std::set<std::string, std::less<>> Index;
 
 public:
-  CfiFunctionIndex() = default;
+  class GUIDIterator
+      : public iterator_adaptor_base<
+            GUIDIterator, std::set<std::string, std::less<>>::const_iterator,
+            std::forward_iterator_tag, GlobalValue::GUID> {
+    using base = iterator_adaptor_base<
+        GUIDIterator, std::set<std::string, std::less<>>::const_iterator,
+        std::forward_iterator_tag, GlobalValue::GUID>;
+
+  public:
+    GUIDIterator() = default;
+    explicit GUIDIterator(std::set<std::string, std::less<>>::const_iterator I)
+        : base(std::move(I)) {}
+
+    GlobalValue::GUID operator*() const {
+      return GlobalValue::getGUID(
+          GlobalValue::dropLLVMManglingEscape(*this->wrapped()));
+    }
+  };
 
+  CfiFunctionIndex() = default;
   template <typename It> CfiFunctionIndex(It B, It E) : Index(B, E) {}
 
   std::set<std::string, std::less<>>::const_iterator begin() const {
@@ -1305,6 +1324,12 @@ class CfiFunctionIndex {
     return Index.end();
   }
 
+  GUIDIterator guid_begin() const { return GUIDIterator(Index.begin()); }
+  GUIDIterator guid_end() const { return GUIDIterator(Index.end()); }
+  iterator_range<GUIDIterator> guids() const {
+    return make_range(guid_begin(), guid_end());
+  }
+
   template <typename... Args> void emplace(Args &&...A) {
     Index.emplace(std::forward<Args>(A)...);
   }

llvm/lib/LTO/LTO.cpp

@@ -1437,12 +1437,10 @@ class InProcessThinBackend : public ThinBackendProc {
                         OnWrite, ShouldEmitImportsFiles, ThinLTOParallelism),
         AddStream(std::move(AddStream)), Cache(std::move(Cache)),
         ShouldEmitIndexFiles(ShouldEmitIndexFiles) {
-    for (auto &Name : CombinedIndex.cfiFunctionDefs())
-      CfiFunctionDefs.insert(
-          GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(Name)));
-    for (auto &Name : CombinedIndex.cfiFunctionDecls())
-      CfiFunctionDecls.insert(
-          GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(Name)));
+    auto &Defs = CombinedIndex.cfiFunctionDefs();
+    CfiFunctionDefs.insert(Defs.guid_begin(), Defs.guid_end());
+    auto &Decls = CombinedIndex.cfiFunctionDecls();
+    CfiFunctionDecls.insert(Decls.guid_begin(), Decls.guid_end());
   }
 
   virtual Error runThinLTOBackendThread(
@@ -1965,12 +1963,10 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache,
 
   // Any functions referenced by the jump table in the regular LTO object must
   // be exported.
-  for (auto &Def : ThinLTO.CombinedIndex.cfiFunctionDefs())
-    ExportedGUIDs.insert(
-        GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(Def)));
-  for (auto &Decl : ThinLTO.CombinedIndex.cfiFunctionDecls())
-    ExportedGUIDs.insert(
-        GlobalValue::getGUID(GlobalValue::dropLLVMManglingEscape(Decl)));
+  auto &Defs = ThinLTO.CombinedIndex.cfiFunctionDefs();
+  ExportedGUIDs.insert(Defs.guid_begin(), Defs.guid_end());
+  auto &Decls = ThinLTO.CombinedIndex.cfiFunctionDecls();
+  ExportedGUIDs.insert(Decls.guid_begin(), Decls.guid_end());
 
   auto isExported = [&](StringRef ModuleIdentifier, ValueInfo VI) {
     const auto &ExportList = ExportLists.find(ModuleIdentifier);