From 1eb9a0297cb639323e97ca7f02123b035bf0b24b Mon Sep 17 00:00:00 2001 From: Zachary Turner Date: Thu, 4 May 2017 23:53:29 +0000 Subject: [PDB] Don't build the entire source file list up front. I tried to run llvm-pdbdump on a very large (~1.5GB) PDB to try and identify show-stopping performance problems. This patch addresses the first such problem. When loading the DBI stream, before anyone has even tried to access a single record, we build an in memory map of every source file for every module. In the particular PDB I was using, this was over 85 million files. Specifically, the complexity is O(m*n) where m is the number of modules and n is the average number of source files (including headers) per module. The whole reason for doing this was so that we could have constant time access to any module and any of its source file lists. However, we can still get O(1) access to the source file list for a given module with a simple O(m) precomputation, and access to the list of modules is already O(1) anyway. So this patches reduces the O(m*n) up-front precomputation to an O(m) one, where n is ~6,500 and n*m is about 85 million in my pathological test case. Differential Revision: https://reviews.llvm.org/D32870 llvm-svn: 302205 --- llvm/lib/DebugInfo/PDB/Native/NativeExeSymbol.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'llvm/lib/DebugInfo/PDB/Native/NativeExeSymbol.cpp') diff --git a/llvm/lib/DebugInfo/PDB/Native/NativeExeSymbol.cpp b/llvm/lib/DebugInfo/PDB/Native/NativeExeSymbol.cpp index ec2a4b87457..bb52560be16 100644 --- a/llvm/lib/DebugInfo/PDB/Native/NativeExeSymbol.cpp +++ b/llvm/lib/DebugInfo/PDB/Native/NativeExeSymbol.cpp @@ -26,7 +26,7 @@ NativeExeSymbol::findChildren(PDB_SymType Type) const { case PDB_SymType::Compiland: { auto Dbi = File.getPDBDbiStream(); if (Dbi) { - const auto Modules = Dbi->modules(); + const DbiModuleList &Modules = Dbi->modules(); return std::unique_ptr( new NativeEnumModules(Session, Modules)); } -- cgit v1.2.3