[libcxxabi][demangle] create helper for std::string_view::starts_with
Add C++ 20 style starts_with to replace StringView::startsWith in
LLVMDemangle. Due to library layering (LLVMSupport depends on
LLVMDemangle), we add the utility header under llvm/Demangle, instead of
llvm/ADT or llvm/Support.
Modify this in libcxxabi, then copy this over to llvm.
Reviewed By: MaskRay, #libc_abi, phosek
Differential Revision: https://reviews.llvm.org/D148556
GitOrigin-RevId: 691c4800be8018d8ad03f0e25be3672acbdfe403
2 files changed
