The =delete overload of StringRef is also a great idea. It just helped me catch all the places where we were initializing global option tables from const char *s
On Wed, Sep 21, 2016 at 2:28 PM Zachary Turner <ztur...@google.com> wrote: > On Wed, Sep 21, 2016 at 2:20 PM Greg Clayton <gclay...@apple.com> wrote: > > > > On Sep 21, 2016, at 1:55 PM, Zachary Turner <ztur...@google.com> wrote: > > > > :-/ The same thing happens if you write Foo &f = *nullptr; It's a > reference. > > I might be a good idea to add an overloaded constructor for nullptr and > void * and delete them so that we can't implicitly create a StringRef from > nullptr or NULL and cause as crash as it wouldn't compile in the first > place. > > > > > Did you try StringRef::withNullAsEmpty()? > > I am still catching code conversion issues with things like: > > if (name == nullptr) > > > Yea you have to handle it on a case by case basis. What I've been doing > is to look around the surrounding code. If it's obvious that it's not null > (because it was just checked above, or because it's .c_str() of something, > or it came from a string literal, or whatever, then i just call > llvm::StringRef(name); If I don't know, even if I can probably guess, I do > one of two things. If it seems like a rabbit hole you don't want to > venture into, just do withNullAsEmpty. If it's a trivial utility function > that doesn't pass the string through many layers of nested calls, go change > that function to return a StringRef, then come back. > > Another thing that's helped me a lot (although it will make the code > slightly verbose in the short term) is that any function I'm changing the > signature of from const char* to StringRef, copy the declaration and > =delete the const char* version. This way the compiler won't allow the > implicit conversion, and you'll be forced to fix up every callsite. This > is annoying because 99% of the time you end up explicitly constructing > StringRefs from literals, which will obviously work, but it's the only way > to guarantee that the conversion won't introduce null pointer errors. > > Once the code is more or less done, we can go back and remove all the > =delete functions we added so you don't have to write explicit conversions > anymore. >
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