labath added inline comments.
================
Comment at: lldb/tools/driver/Driver.cpp:673-674
+static void sigtstp_handler(int signo) {
if (g_driver != nullptr)
g_driver->GetDebugger().SaveInputTerminalState();
----------------
JDevlieghere wrote:
> andcarminati wrote:
> > JDevlieghere wrote:
> > > labath wrote:
> > > > JDevlieghere wrote:
> > > > > I see an opportunity for a little RAII helper.
> > > > What kind of a helper did you have in mind? Practically the entire
> > > > function consists of setup and teardown in preparation for the
> > > > `raise(signo)` call. If I wanted to be fancy I could put all of that in
> > > > a helper, but I don't think that would make it cleaner. Plus, we also
> > > > need to be careful about the functions we call from a signal handler,
> > > > and I really don't know whether e.g. `llvm::make_scope_exit` is
> > > > guaranteed to not allocate (heap) memory.
> > > I was only referring to the Save/RestoreInputTerminalState() part of this
> > > function. Something like:
> > >
> > > ```
> > > class TerminalStateRAII() {
> > > public:
> > > TerminalStateRAII(Driver* driver) : driver(m_driver) {
> > > if (m_driver)
> > > m_driver->GetDebugger().SaveInputTerminalState();
> > > }
> > >
> > > ~SignalHelper() {
> > > if (m_driver)
> > > m_driver->GetDebugger().SaveInputTerminalState();
> > > }
> > >
> > > private:
> > > Driver* m_driver;
> > > };
> > > ```
> > >
> > > Obviously, this isn't at all important, just something that came to mind.
> > I think this is a good idea to reduce code duplication. Another approach:
> >
> > ```
> > class TerminalStateRAII() {
> > public:
> > TerminalStateRAII(Driver* driver) : driver(m_driver) {
> > SaveInputTerminalState();
> > }
> >
> > ~TerminalStateRAII() {
> > SaveInputTerminalState();
> > }
> >
> > private:
> > Driver* m_driver;
> > void SaveInputTerminalState(){
> > if (m_driver)
> > m_driver->GetDebugger().SaveInputTerminalState();
> > }
> > };
> >
> > ```
> That's a typo on my part, the destructor needs to call
> `RestoreInputTerminalState` (as opposed to `SaveInputTerminalState`).
Ok, I see. If this was a more complex function (e.g. multiple return points),
then I'd agree, but this function is really simple and linear (just like a
signal handler should be). I am not convinced by the "code duplication"
argument -- the way I see it, the helper class replaces 4 lines of (simple)
code with ~15 lines of boilerplate. And this function is literally the only
caller of Save/RestoreInputTerminalState.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D120320/new/
https://reviews.llvm.org/D120320
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