From ad7211df6f257e39da2e5a11b2456b4488f32a1e Mon Sep 17 00:00:00 2001 From: Oliver Bruns Date: Mon, 6 Apr 2020 10:38:30 +0200 Subject: [PATCH] [clang] fix undefined behaviour in RawComment::getFormattedText() Summary: Calling `back()` and `pop_back()` on the empty string is undefined behavior [1,2]. The issue manifested itself as an uncaught `std::out_of_range` exception when running `clangd` compiled on RHEL7 using devtoolset-9. [1] https://en.cppreference.com/w/cpp/string/basic_string/back [2] https://en.cppreference.com/w/cpp/string/basic_string/pop_back Fixes: 1ff7c32fc91c607b690d4bb9cf42f406be8dde68 Reviewers: teemperor, ioeric, cfe-commits Reviewed By: teemperor Subscribers: ilya-biryukov, kadircet, usaxena95 Tags: #clang Differential Revision: https://reviews.llvm.org/D77468 --- clang/lib/AST/RawCommentList.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/clang/lib/AST/RawCommentList.cpp b/clang/lib/AST/RawCommentList.cpp index 8552b4fcd2b..a8d15036cab 100644 --- a/clang/lib/AST/RawCommentList.cpp +++ b/clang/lib/AST/RawCommentList.cpp @@ -431,7 +431,7 @@ std::string RawComment::getFormattedText(const SourceManager &SourceMgr, }; auto DropTrailingNewLines = [](std::string &Str) { - while (Str.back() == '\n') + while (!Str.empty() && Str.back() == '\n') Str.pop_back(); }; -- 2.25.2