Add non-blocking Wait() for launched processes

- New ProcessInfo class to encapsulate information about child processes.
- Generalized the Wait() to support non-blocking wait on child processes.
- ExecuteNoWait() now returns a ProcessInfo object with information about
  the launched child. Users will be able to use this object to
  perform non-blocking wait.
- ExecuteNoWait() now accepts an ExecutionFailed param that tells if execution
  failed or not.

These changes will allow users to implement basic process parallel
tools.

Differential Revision: http://llvm-reviews.chandlerc.com/D1728

llvm-svn: 191763

1 files changed, 23 insertions, 13 deletions

diff --git a/llvm/lib/Support/Program.cpp b/llvm/lib/Support/Program.cpp
index 79f7e5fbb7e..83f2ec4f0fc 100644
--- a/llvm/lib/Support/Program.cpp
+++ b/llvm/lib/Support/Program.cpp
@@ -22,30 +22,40 @@ using namespace sys;
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
-static bool Execute(void **Data, StringRef Program, const char **args,
+static bool Execute(ProcessInfo &PI, StringRef Program, const char **args,
                     const char **env, const StringRef **Redirects,
                     unsigned memoryLimit, std::string *ErrMsg);
 
-static int Wait(void *&Data, StringRef Program, unsigned secondsToWait,
-                std::string *ErrMsg);
-
 int sys::ExecuteAndWait(StringRef Program, const char **args, const char **envp,
                         const StringRef **redirects, unsigned secondsToWait,
                         unsigned memoryLimit, std::string *ErrMsg,
                         bool *ExecutionFailed) {
-  void *Data = 0;
-  if (Execute(&Data, Program, args, envp, redirects, memoryLimit, ErrMsg)) {
-    if (ExecutionFailed) *ExecutionFailed = false;
-    return Wait(Data, Program, secondsToWait, ErrMsg);
+  ProcessInfo PI;
+  if (Execute(PI, Program, args, envp, redirects, memoryLimit, ErrMsg)) {
+    if (ExecutionFailed)
+      *ExecutionFailed = false;
+    ProcessInfo Result = Wait(PI, secondsToWait, true, ErrMsg);
+    return Result.ReturnCode;
   }
-  if (ExecutionFailed) *ExecutionFailed = true;
+
+  if (ExecutionFailed)
+    *ExecutionFailed = true;
+
   return -1;
 }
 
-void sys::ExecuteNoWait(StringRef Program, const char **args, const char **envp,
-                        const StringRef **redirects, unsigned memoryLimit,
-                        std::string *ErrMsg) {
-  Execute(/*Data*/ 0, Program, args, envp, redirects, memoryLimit, ErrMsg);
+ProcessInfo sys::ExecuteNoWait(StringRef Program, const char **args,
+                               const char **envp, const StringRef **redirects,
+                               unsigned memoryLimit, std::string *ErrMsg,
+                               bool *ExecutionFailed) {
+  ProcessInfo PI;
+  if (ExecutionFailed)
+    *ExecutionFailed = false;
+  if (!Execute(PI, Program, args, envp, redirects, memoryLimit, ErrMsg))
+    if (ExecutionFailed)
+      *ExecutionFailed = true;
+
+  return PI;
 }
 
 // Include the platform-specific parts of this class.