From ed8f9589a8767d3a61aeda6661b74891df80fa18 Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Sun, 20 Mar 2011 15:52:24 +0000 Subject: [PATCH] Avoid initializing posix_spawn_file_actions_t if not used. - glibc falls back to fork+exec if a file actions object is present. - On BSDs this saves a malloc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127969 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Support/Unix/Program.inc | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) diff --git a/lib/Support/Unix/Program.inc b/lib/Support/Unix/Program.inc index 1104bc7503e..6efc8cd5e4d 100644 --- a/lib/Support/Unix/Program.inc +++ b/lib/Support/Unix/Program.inc @@ -132,7 +132,7 @@ static bool RedirectIO(const Path *Path, int FD, std::string* ErrMsg) { #ifdef HAVE_POSIX_SPAWN static bool RedirectIO_PS(const Path *Path, int FD, std::string *ErrMsg, - posix_spawn_file_actions_t &FileActions) { + posix_spawn_file_actions_t *FileActions) { if (Path == 0) // Noop return false; const char *File; @@ -142,7 +142,7 @@ static bool RedirectIO_PS(const Path *Path, int FD, std::string *ErrMsg, else File = Path->c_str(); - if (int Err = posix_spawn_file_actions_addopen(&FileActions, FD, + if (int Err = posix_spawn_file_actions_addopen(FileActions, FD, File, FD == 0 ? O_RDONLY : O_WRONLY|O_CREAT, 0666)) return MakeErrMsg(ErrMsg, "Cannot dup2", Err); return false; @@ -185,10 +185,13 @@ Program::Execute(const Path &path, const char **args, const char **envp, // posix_spawn. It is more efficient than fork/exec. #ifdef HAVE_POSIX_SPAWN if (memoryLimit == 0) { - posix_spawn_file_actions_t FileActions; - posix_spawn_file_actions_init(&FileActions); + posix_spawn_file_actions_t FileActionsStore; + posix_spawn_file_actions_t *FileActions = 0; if (redirects) { + FileActions = &FileActionsStore; + posix_spawn_file_actions_init(FileActions); + // Redirect stdin/stdout. if (RedirectIO_PS(redirects[0], 0, ErrMsg, FileActions) || RedirectIO_PS(redirects[1], 1, ErrMsg, FileActions)) @@ -200,7 +203,7 @@ Program::Execute(const Path &path, const char **args, const char **envp, } else { // If stdout and stderr should go to the same place, redirect stderr // to the FD already open for stdout. - if (int Err = posix_spawn_file_actions_adddup2(&FileActions, 1, 2)) + if (int Err = posix_spawn_file_actions_adddup2(FileActions, 1, 2)) return !MakeErrMsg(ErrMsg, "Can't redirect stderr to stdout", Err); } } @@ -216,10 +219,11 @@ Program::Execute(const Path &path, const char **args, const char **envp, // Explicitly initialized to prevent what appears to be a valgrind false // positive. pid_t PID = 0; - int Err = posix_spawn(&PID, path.c_str(), &FileActions, /*attrp*/0, + int Err = posix_spawn(&PID, path.c_str(), FileActions, /*attrp*/0, const_cast(args), const_cast(envp)); - posix_spawn_file_actions_destroy(&FileActions); + if (FileActions) + posix_spawn_file_actions_destroy(FileActions); if (Err) return !MakeErrMsg(ErrMsg, "posix_spawn failed", Err); -- 2.34.1