[PATCH] Allow for the use of StringRef command line options instead of cl::opt<std::string>

[Chris Lattner]

On Aug 14, 2013, at 4:06 PM, Puyan Lotfi <plotfi at apple.com> wrote:

> Oh wow. I see that.
> 
> I am not completely sure how the char* arrays would get handled this way.
> I did not make any clang modifications in this patch (although since clang is using the cl library it is affected) but I noticed that the use of cl:: in the llvm source tree made use of global cl::opt variables that specify the opt type.
> I don’t see that in the files handling the -mllvm options; I’ll have to look at the CommandLine.cpp code a little more closely to be sure in this case that the char*’s aren’t being implicitly put into StringRefs that might have their data pointers deallocated after cl::ParseCommandLineOptions() is called. 

 After thinking about it for a bit, how about we go with this approach:

1. Document ParseCommandLineOptions/ParseEnvironmentOptions to only work with strings that live forever in CommandLine.h
2. Change clang to leak (or store globally) the strings that are affected.

I don't think it is worth designing a context system or anything like that to handle this case. 

-Chris