On Wed, Feb 15, 2017 at 10:47 AM Reid Kleckner <r...@google.com> wrote:
> On Wed, Feb 15, 2017 at 10:35 AM, Greg Clayton via lldb-dev < > lldb-dev@lists.llvm.org> wrote: > > I am fine with switching mmap over to llvm if it works. One important > thing to LLDB is we have a "mmap if not on remote file system" that must > continue to work. If you mmap something from a network drive and then it > gets disconnected, you can crash LLDB. So we have a function we used that > implements mmap if local, read all contents if remote, that must work to > avoid crashes. > > > LLVM's MemoryBuffer API already serves too many different use cases. > Initially it was designed to be a utility for efficiently reading source > file inputs. It has a bunch of functionality around ensuring that the > buffer is null terminated, and a boolean to avoid using mmap when the user > might modify the file concurrently. It's too complicated. I wouldn't > recommend using it without a good reason beyond just reusing a platform > abstraction. mmap and MapViewOfFile are not that complicated. LLDB is > probably better off doing its own thing unless it needs to pass mapped file > contents to other parts of LLVM, like maybe clang's VFS. > I just took a look and it seems like almost a drop in replacement. Only thing that would need changing is updating shouldUseMmap() to return false if a file is on a network share. But this seems like a good change independently of lldb. After that all lldb has to do is say MemoryBuffer::getOpenFile() and everything works. Is there a good reason *not* to use it? Evenif internally the implementation is complex, the external interface is not >
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