[LLVM-C] Use Length-Providing Value Name Getters and Setters

Summary:
- Provide LLVMGetValueName2 and LLVMSetValueName2 that return and take the length of the provided C string respectively
- Deprecate LLVMGetValueName and LLVMSetValueName

Reviewers: whitequark, deadalnix

Reviewed By: whitequark

Subscribers: llvm-commits, harlanhaskins

Differential Revision: https://reviews.llvm.org/D46890

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332810 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed