The `Twine::str()` function currently always allocates heap memory via `std::string`. However, some instances of `Twine` don't need an intermediate buffer at all, and the rest can attempt to print into a stack buffer first.
This is intentionally not making use of `Twine::isSingleStringLiteral()` from D157010 to skip saving the string in the bump-pointer allocator, since the `StringSaver` documentation suggests that MUST happen for every given string.
Reviewed By: benlangmuir
Differential Revision: https://reviews.llvm.org/D157015
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
StringSaver now always saves to a BumpPtrAllocator.
The only reason for having the virtual saveImpl is so lld can have a
thread safe version.
The reason for the distinct BumpPtrStringSaver class is to avoid the
virtual destructor.
llvm-svn: 239669
