From 4d7188abfdf2c8303fdcad300cd7c06c4b4c30c0 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Thu, 29 Jul 2021 14:42:04 -0400 Subject: gdbsupport: add debug assertions in gdb::optional::get The libstdc++ version of optional contains some runtime checks enabled when _GLIBCXX_DEBUG is defined. I think it would be useful if our version contained similar checks. Add checks in the two `get` methods, also conditional on _GLIBCXX_DEBUG. I think it's simpler to use that macro rather than introducing a new GDB-specific one, as I think that if somebody is interested in enabling these runtime checks, they'll also be interested in enabling the libstdc++ runtime checks (and vice-versa). I implemented these checks using gdb_assert. Note that gdb_assert throws (after querying the user), and we are in noexcept methods. That means that std::terminate / abort will immediately be called. I think this is ok, since if those were "real" _GLIBCXX_DEBUG checks, abort would be called straight away. If I add a dummy failure, it looks like so: $ ./gdb -q -nx --data-directory=data-directory /home/simark/src/binutils-gdb/gdb/../gdbsupport/gdb_optional.h:206: internal-error: T& gdb::optional::get() [with T = int]: Assertion `this->has_value ()' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) n [1] 658767 abort (core dumped) ./gdb -q -nx --data-directory=data-directory Change-Id: Iadfdcd131425bd2ca6a2de30d7b22e9b3cc67793 --- gdbsupport/gdb_optional.h | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'gdbsupport') diff --git a/gdbsupport/gdb_optional.h b/gdbsupport/gdb_optional.h index e79ba2c..745b2ba 100644 --- a/gdbsupport/gdb_optional.h +++ b/gdbsupport/gdb_optional.h @@ -200,8 +200,20 @@ private: } /* The get operations have m_instantiated as a precondition. */ - T &get () noexcept { return m_item; } - constexpr const T &get () const noexcept { return m_item; } + T &get () noexcept + { +#if defined(_GLIBCXX_DEBUG) + gdb_assert (this->has_value ()); +#endif + return m_item; + } + constexpr const T &get () const noexcept + { +#if defined(_GLIBCXX_DEBUG) + gdb_assert (this->has_value ()); +#endif + return m_item; + } /* The object. */ union -- cgit v1.1