Revert "Reland "[ThinLTO] Populate declaration import status except for distributed ThinLTO under a default-off new option" (#92718) (#94503)

This reverts commit e33db249b53fb70dce62db3ebd82d42239bd1d9d.

The change from *set to *map increases memory usage, and caused indexing
OOM in some applications. Need to profile offline to bring the memory
usage down.

1 files changed, 1 insertions, 8 deletions

diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
index 76223e8..21aed79 100644
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -720,14 +720,7 @@ bool lto::initImportList(const Module &M,
       if (Summary->modulePath() == M.getModuleIdentifier())
         continue;
       // Add an entry to provoke importing by thinBackend.
-      // Try emplace the entry first. If an entry with the same key already
-      // exists, set the value to 'std::min(existing-value, new-value)' to make
-      // sure a definition takes precedence over a declaration.
-      auto [Iter, Inserted] = ImportList[Summary->modulePath()].try_emplace(
-          GUID, Summary->importType());
-
-      if (!Inserted)
-        Iter->second = std::min(Iter->second, Summary->importType());
+      ImportList[Summary->modulePath()].insert(GUID);
     }
   }
   return true;