From 40ec4d26b7622eb07ad8d5f02da0dd43a1dc74b5 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Sat, 27 Jul 2013 21:59:57 +0000 Subject: [PATCH] Reduce stack frame size by avoiding a large token vector on an error path. Beginning with svn r186971, we noticed an internal test started to fail when using clang built with LTO. After much investigation, it turns out that there are no blatant bugs here, we are just running out of stack space and crashing. Preprocessor::ReadFunctionLikeMacroArgs already has one vector of 64 Tokens, and r186971 added another. When built with LTO, that function is inlined into Preprocessor::HandleMacroExpandedIdentifier, which for our internal test is invoked in a deep recursive cycle. I'm leaving the original 64 Token vector alone on the assumption that it is important for performance, but the new FixedArgTokens vector is only used on an error path, so it should be OK if it requires additional heap storage. It would be even better if we could avoid the deep recursion, but I think this change is a good thing to do regardless. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@187315 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Lex/PPMacroExpansion.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp index 0a7f079df6..899fba600d 100644 --- a/lib/Lex/PPMacroExpansion.cpp +++ b/lib/Lex/PPMacroExpansion.cpp @@ -681,7 +681,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName, // TODO: See if this can be generalized to angle brackets for templates // inside macro arguments. - SmallVector FixedArgTokens; + SmallVector FixedArgTokens; unsigned FixedNumArgs = 0; SmallVector ParenHints, InitLists; if (!GenerateNewArgTokens(*this, ArgTokens, FixedArgTokens, FixedNumArgs, -- 2.50.1