[PATCH][llvm-c] expose sys::getProcessTriple

[Filip Pizlo]

Ping!

-F


On Jun 27, 2013, at 8:05 PM, Filip Pizlo <fpizlo at apple.com> wrote:

> The fact that this isn't already exposed makes using some other C APIs, like the disassembler API, really awkward in a JIT context - you don't want to have to describe to LLVM what the target name is for the process you're in, when LLVM already has this information.
> 
> The challenge here is that sys::getProcessTriple() returns a std::string that it allocates itself.  So we can't just have a "LLVMGetProcessTarget()" that returns a char*, unless we then require the user to free() that char*.  I considered that but I feared that it would have been confusing to users: for example LLVMGetTarget() returns a char* that doesn't require deallocation.  So, to make the ownership rules more explicit, I made the API take an already allocated char* and a size.
> 
> I wanted to allow for this idiom for people who don't want to guess the right string size:
> 
> size_t targetSize = LLVMGetProcessTarget(0, 0);
> char *target = malloc(targetSize);
> LLVMGetProcessTarget(target, targetSize);
> 
> This means that I couldn't just call snprintf().  I actually ended up getting the buffer allocation wrong on the first try, so I include some test coverage to make sure that it really isn't messed up.
> 
> -Filip
> 
> <GetProcessTarget.patch>