From d933922e6963e52c27e828813f1e66a0e5255291 Mon Sep 17 00:00:00 2001
From: sergesanspaille <sguelton@redhat.com>
Date: Tue, 19 May 2020 13:12:28 +0000
Subject: [PATCH] Backport ad7211df6f257e39da2e5a11b2456b4488f32a1e, see
 rhbz#1825593

---
 ...ned-behaviour-in-RawComment-getForma.patch | 47 +++++++++++++++++++
 clang.spec                                    |  7 ++-
 2 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 0001-clang-fix-undefined-behaviour-in-RawComment-getForma.patch

diff --git a/0001-clang-fix-undefined-behaviour-in-RawComment-getForma.patch b/0001-clang-fix-undefined-behaviour-in-RawComment-getForma.patch
new file mode 100644
index 0000000..ccdb423
--- /dev/null
+++ b/0001-clang-fix-undefined-behaviour-in-RawComment-getForma.patch
@@ -0,0 +1,47 @@
+From ad7211df6f257e39da2e5a11b2456b4488f32a1e Mon Sep 17 00:00:00 2001
+From: Oliver Bruns <obruns@gmail.com>
+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
+
diff --git a/clang.spec b/clang.spec
index b714a38..483a76d 100644
--- a/clang.spec
+++ b/clang.spec
@@ -4,7 +4,7 @@
 %global min_ver 0
 %global patch_ver 0
 #%%global rc_ver 6
-%global baserelease 1
+%global baserelease 2
 
 %global clang_tools_binaries \
 	%{_bindir}/clang-apply-replacements \
@@ -98,6 +98,7 @@ Source4:	https://prereleases.llvm.org/%{version}/hans-gpg-key.asc
 Patch4:		0002-gtest-reorg.patch
 Patch11:	0001-ToolChain-Add-lgcc_s-to-the-linker-flags-when-using-.patch
 Patch13:	0001-Make-funwind-tables-the-default-for-all-archs.patch
+Patch14:	0001-clang-fix-undefined-behaviour-in-RawComment-getForma.patch
 
 # Not Upstream
 Patch15:	0001-clang-Don-t-install-static-libraries.patch
@@ -250,6 +251,7 @@ pathfix.py -i %{__python3} -pn \
 %patch4 -p1 -b .gtest
 %patch11 -p1 -b .libcxx-fix
 %patch13 -p2 -b .unwind-all
+%patch14 -p2 -b .clangd
 %patch15 -p2 -b .no-install-static
 
 mv ../%{clang_tools_srcdir} tools/extra
@@ -469,6 +471,9 @@ LD_LIBRARY_PATH=%{buildroot}%{_libdir} ninja check-all -C _build || \
 
 %endif
 %changelog
+* Tue May 19 2020 sguelton@redhat.com - 10.0.0-2
+- Backport ad7211df6f257e39da2e5a11b2456b4488f32a1e, see rhbz#1825593
+
 * Thu Mar 26 2020 sguelton@redhat.com - 10.0.0-1
 - 10.0.0 final