diff --git a/llvm/lib/Support/Unix/Program.inc b/llvm/lib/Support/Unix/Program.inc
--- a/llvm/lib/Support/Unix/Program.inc
+++ b/llvm/lib/Support/Unix/Program.inc
@@ -340,10 +340,12 @@
 namespace llvm {
 namespace sys {
 
-#ifndef _AIX
-using ::wait4;
-#else
+#if defined(_AIX)
 static pid_t(wait4)(pid_t pid, int *status, int options, struct rusage *usage);
+#elif defined(__Fuchsia__)
+using ::waitpid;
+#else
+using ::wait4;
 #endif
 
 } // namespace sys
@@ -414,12 +416,18 @@
   // Parent process: Wait for the child process to terminate.
   int status = 0;
   ProcessInfo WaitResult;
+#ifndef __Fuchsia__
   rusage Info;
   if (ProcStat)
     ProcStat->reset();
+#endif
 
   do {
+#ifndef __Fuchsia__
     WaitResult.Pid = sys::wait4(ChildPid, &status, WaitPidOptions, &Info);
+#else
+    WaitResult.Pid = sys::waitpid(ChildPid, &status, WaitPidOptions);
+#endif
   } while (WaitUntilTerminates && WaitResult.Pid == -1 && errno == EINTR);
 
   if (WaitResult.Pid != PI.Pid) {
@@ -459,6 +467,7 @@
     sigaction(SIGALRM, &Old, nullptr);
   }
 
+#ifndef __Fuchsia__
   if (ProcStat) {
     std::chrono::microseconds UserT = toDuration(Info.ru_utime);
     std::chrono::microseconds KernelT = toDuration(Info.ru_stime);
@@ -468,6 +477,7 @@
 #endif
     *ProcStat = ProcessStatistics{UserT + KernelT, UserT, PeakMemory};
   }
+#endif
 
   // Return the proper exit status. Detect error conditions
   // so we can return -1 for them and set ErrMsg informatively.