Author: Jonas Devlieghere Date: 2022-02-04T10:17:39-08:00 New Revision: aed965d55d460ebcc2b442b9d799b4c1ab929157
URL: https://github.com/llvm/llvm-project/commit/aed965d55d460ebcc2b442b9d799b4c1ab929157 DIFF: https://github.com/llvm/llvm-project/commit/aed965d55d460ebcc2b442b9d799b4c1ab929157.diff LOG: [lldb] Don't construct the demangled strings while indexing the symbol table The symbol table needs to demangle all symbol names when building its index. However, this doesn't require the full mangled name: we only need the base name and the function declaration context. Currently, we always construct the demangled string during indexing and cache it in the string pool as a way to speed up future lookups. Constructing the demangled string is by far the most expensive step of the demangling process, because the output string can be exponentially larger than the input and unless you're dumping the symbol table, many of those demangled names will not be needed again. This patch avoids constructing the full demangled string when we can partially demangle. This speeds up indexing and reduces memory usage. I gathered some numbers by attaching to Slack: Before ------ Memory usage: 280MB Benchmark 1: ./bin/lldb -n Slack -o quit Time (mean ± σ): 4.829 s ± 0.518 s [User: 4.012 s, System: 0.208 s] Range (min … max): 4.624 s … 6.294 s 10 runs After ----- Memory usage: 189MB Benchmark 1: ./bin/lldb -n Slack -o quit Time (mean ± σ): 4.182 s ± 0.025 s [User: 3.536 s, System: 0.192 s] Range (min … max): 4.152 s … 4.233 s 10 runs Differential revision: https://reviews.llvm.org/D118814 Added: Modified: lldb/source/Core/Mangled.cpp lldb/source/Symbol/Symtab.cpp lldb/test/API/macosx/dyld-trie-symbols/TestDyldTrieSymbols.py Removed: ################################################################################ diff --git a/lldb/source/Core/Mangled.cpp b/lldb/source/Core/Mangled.cpp index f3c0de40c4ef4..ba3447020adbb 100644 --- a/lldb/source/Core/Mangled.cpp +++ b/lldb/source/Core/Mangled.cpp @@ -214,24 +214,16 @@ bool Mangled::DemangleWithRichManglingInfo( case eManglingSchemeItanium: // We want the rich mangling info here, so we don't care whether or not // there is a demangled string in the pool already. - if (context.FromItaniumName(m_mangled)) { - // If we got an info, we have a name. Copy to string pool and connect the - // counterparts to accelerate later access in GetDemangledName(). - m_demangled.SetStringWithMangledCounterpart(context.ParseFullName(), - m_mangled); - return true; - } else { - m_demangled.SetCString(""); - return false; - } + return context.FromItaniumName(m_mangled); case eManglingSchemeMSVC: { // We have no rich mangling for MSVC-mangled names yet, so first try to // demangle it if necessary. if (!m_demangled && !m_mangled.GetMangledCounterpart(m_demangled)) { if (char *d = GetMSVCDemangledStr(m_mangled.GetCString())) { - // If we got an info, we have a name. Copy to string pool and connect - // the counterparts to accelerate later access in GetDemangledName(). + // Without the rich mangling info we have to demangle the full name. + // Copy it to string pool and connect the counterparts to accelerate + // later access in GetDemangledName(). m_demangled.SetStringWithMangledCounterpart(llvm::StringRef(d), m_mangled); ::free(d); diff --git a/lldb/source/Symbol/Symtab.cpp b/lldb/source/Symbol/Symtab.cpp index 765e7bc9520fd..436f97e623819 100644 --- a/lldb/source/Symbol/Symtab.cpp +++ b/lldb/source/Symbol/Symtab.cpp @@ -328,8 +328,10 @@ void Symtab::InitNameIndexes() { const SymbolType type = symbol->GetType(); if (type == eSymbolTypeCode || type == eSymbolTypeResolver) { - if (mangled.DemangleWithRichManglingInfo(rmc, lldb_skip_name)) + if (mangled.DemangleWithRichManglingInfo(rmc, lldb_skip_name)) { RegisterMangledNameEntry(value, class_contexts, backlog, rmc); + continue; + } } } diff --git a/lldb/test/API/macosx/dyld-trie-symbols/TestDyldTrieSymbols.py b/lldb/test/API/macosx/dyld-trie-symbols/TestDyldTrieSymbols.py index 3455f21392dc4..6f2f1c5b7cee4 100644 --- a/lldb/test/API/macosx/dyld-trie-symbols/TestDyldTrieSymbols.py +++ b/lldb/test/API/macosx/dyld-trie-symbols/TestDyldTrieSymbols.py @@ -43,8 +43,6 @@ def test_dyld_trie_symbols(self): self.assertEqual(unstripped_Z3pat_symbols.GetSize(), 1) unstripped_pat_symbols = unstripped_target.FindSymbols("pat") self.assertEqual(unstripped_pat_symbols.GetSize(), 1) - unstripped_patint_symbols = unstripped_target.FindSymbols("pat(int)") - self.assertEqual(unstripped_patint_symbols.GetSize(), 1) unstripped_bar_symbols = unstripped_target.FindSymbols("bar") self.assertEqual(unstripped_bar_symbols.GetSize(), 1) @@ -77,8 +75,6 @@ def test_dyld_trie_symbols(self): self.assertEqual(stripped_Z3pat_symbols.GetSize(), 1) stripped_pat_symbols = stripped_target.FindSymbols("pat") self.assertEqual(stripped_pat_symbols.GetSize(), 1) - stripped_patint_symbols = stripped_target.FindSymbols("pat(int)") - self.assertEqual(stripped_patint_symbols.GetSize(), 1) # bar should have been strippped. We should not find it, or the # stripping went wrong. _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
