llvm-project

dc92bd03 - [sanitizer_common] [Darwin] Replace pty with pipe on posix_spawn path for spawning symbolizer (#170809)

[sanitizer_common] [Darwin] Replace pty with pipe on posix_spawn path for spawning symbolizer (#170809) Due to a legacy incompatibility with `atos`, we were allocating a pty whenever we spawned the symbolizer. This is no longer necessary and we can use a regular ol' pipe. This PR is split into two commits: - The first removes the pty allocation and replaces it with a pipe. This relocates the `CreateTwoHighNumberedPipes` call to be common to the `posix_spawn` and `StartSubprocess` path. - The second commit adds the `child_stdin_fd_` field to `SymbolizerProcess`, storing the read end of the stdin pipe. By holding on to this fd for the lifetime of the symbolizer, we are able to avoid getting SIGPIPE (which would occur when we write to a pipe whose read-end had been closed due to the death of the symbolizer). This will be very close to solving #120915, but this PR is intentionally not touching the non-posix_spawn path. rdar://165894284