[lldb-dev] "error: summary string parsing error" on Fedora 30

[Bob Eastbrook via lldb-dev]

Thanks for the info.  "frame var --raw msg" is empty on my Fedora 30
system, but populated correctly on Ubuntu 19.04.  E.g., on Fedora 30:

(lldb) frame var --raw msg
(std::string) msg = {}

I compiled with "clang++ -g main.cpp".  Nothing fancy.  Installed
Clang with "dnf install clang".  Again, nothing fancy.

I'm a LLVM newb.  Can you point me in the right direction?




On Fri, Jul 12, 2019 at 1:56 PM Greg Clayton <clayborg at gmail.com> wrote:
>
> We have a summary provider for std::string that is built into LLDB that must not be working with the C++ runtime you are using. The current summary string that is used is in source/Plugins/Language/CPlusPlus/CPlusPlusLanguage.cpp in LoadLibStdcppFormatters:
>
>   lldb::TypeSummaryImplSP std_string_summary_sp(
>       new StringSummaryFormat(stl_summary_flags, "${var._M_dataplus._M_p}"));
>
> So do a "frame var --raw msg" and see what the members of your std::string look like. I am guessing you won't see "_M_dataplus" or "_M_p" in there. The "${var" means your std::string variable, and we are trying to access "msg._M_dataplus._M_p" to see what the string looks like.
>
>
> On Jun 24, 2019, at 10:26 PM, Bob Eastbrook via lldb-dev <lldb-dev at lists.llvm.org> wrote:
>
> With Clang 8.0.0 and libstd++ 9.1.1 on Fedora 30 x86_64, I get this
> error from LLDB when trying to see the value of a string:
>
> "error: summary string parsing error"
>
> The code is simply:
>
> std::string msg{"foo bar baz"};
>
> With libcxx 8.0.0, instead of the above error, I simply see "??" when
> inspecting the msg variable.
>
> All of the above works fine for me in Ubuntu 19.04. I only have the
> problem with Fedora 30.  Tried in both CLion and VS Code.
>
> How should I troubleshoot this?  Could I be missing a package?
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