From 6a780b6766378e3dc9610cba7e12d7eaba196f52 Mon Sep 17 00:00:00 2001 From: Kevin Buettner Date: Fri, 12 Feb 2021 17:53:51 -0700 Subject: [PATCH] Fix completion related libstdc++ assert when using -D_GLIBCXX_DEBUG This commit fixes a libstdc++ assertion failure encountered when running gdb.base/completion.exp. In order to see this problem, GDB must be built with the follow CFLAGS and CXXFLAGS as part of the configure line: CFLAGS='-D_GLIBCXX_DEBUG' CXXFLAGS='-D_GLIBCXX_DEBUG' (Also, this problem was encountered using Fedora rawhide. It might not be reproducible in Fedora versions prior to Fedora 34.) Using the gdb.base/completion.exp test program, the problem can be observed as follows: [kev@rawhide-1 gdb]$ ./gdb -q testsuite/outputs/gdb.base/completion/completion Reading symbols from testsuite/outputs/gdb.base/completion/completion... (gdb) start Temporary breakpoint 1 at 0x401179: file ../../worktree-master/gdb/testsuite/gdb.base/break.c, line 43. Starting program: testsuite/outputs/gdb.base/completion/completion Temporary breakpoint 1, main (argc=1, argv=0x7fffffffd718, envp=0x7fffffffd728) at ../../worktree-master/gdb/testsuite/gdb.base/break.c:43 43 if (argc == 12345) { /* an unlikely value < 2^16, in case uninited */ /* set breakpoint 6 here */ (gdb) p /usr/include/c++/11/string_view:211: constexpr const value_type& std::basic_string_view<_CharT, _Traits>::operator[](std::basic_string_view<_CharT, _Traits>::size_type) const [with _CharT = char; _Traits = std::char_traits; std::basic_string_view<_CharT, _Traits>::const_reference = const char&; std::basic_string_view<_CharT, _Traits>::size_type = long unsigned int]: Assertion '__pos < this->_M_len' failed. Aborted (core dumped) (Note that I added "" to make it clear where the tab key was pressed.) gdb/ChangeLog: * ada-lang.c (ada_fold_name): Check for non-empty string prior to accessing it. (ada_lookup_name_info): Likewise. --- gdb/ChangeLog | 6 ++++++ gdb/ada-lang.c | 4 ++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 204bb40b2c9..030eb9f5983 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2021-02-17 Kevin Buettner + + * ada-lang.c (ada_fold_name): Check for non-empty string prior + to accessing it. + (ada_lookup_name_info): Likewise. + 2021-02-13 Mike Frysinger * aclocal.m4: Regenerate. diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c index 416a45be58e..419347f776d 100644 --- a/gdb/ada-lang.c +++ b/gdb/ada-lang.c @@ -980,7 +980,7 @@ ada_fold_name (gdb::string_view name) int len = name.size (); GROW_VECT (fold_buffer, fold_buffer_size, len + 1); - if (name[0] == '\'') + if (!name.empty () && name[0] == '\'') { strncpy (fold_buffer, name.data () + 1, len - 2); fold_buffer[len - 2] = '\000'; @@ -13650,7 +13650,7 @@ ada_lookup_name_info::ada_lookup_name_info (const lookup_name_info &lookup_name) { gdb::string_view user_name = lookup_name.name (); - if (user_name[0] == '<') + if (!user_name.empty () && user_name[0] == '<') { if (user_name.back () == '>') m_encoded_name -- 2.30.2