weiwang added a comment. Tried to make `Sema::DeclsToCheckForDeferredDiags` `llvm::SmallSetVector`. The heap RSS did drop significantly (from peak 100GB to 59GB) , but not as good as the current fix (peak 26GB), which makes `ASTReader::DeclsToCheckForDeferredDiags` `llvm::SmallSetVector`.
I think the reason is that the duplicated decls are read from multiple module file sources (`ASTReader::ReadAST()` -> `ASTReader::ReadASTBlock()`), then stored into `ASTReader::DeclsToCheckForDeferredDiags`, then goes into `Sema::DeclsToCheckForDeferredDiags` in `ASTReader::ReadDeclsToCheckForDeferredDiags()`. Doing dedup at the early stage when the decls were just read in `ASTReader` is more effective at reducing RSS. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D101793/new/ https://reviews.llvm.org/D101793 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
