Adding out-of-process execution support to lli.

At this time only Unix-based systems are supported.  Windows has stubs and should re-route to the simulated mode.

Thanks to Sriram Murali for contributions to this patch.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191843 91177308-0d34-0410-b5e6-96231b3b80d8

tools/lli/Unix/RemoteTargetExternal.inc

@@ -0,0 +1,91 @@
+//=- RemoteTargetExternal.inc - LLVM out-of-process JIT execution for Unix --=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implementation of the Unix-specific parts of the RemoteTargetExternal class
+// which executes JITed code in a separate process from where it was built.
+//
+//===----------------------------------------------------------------------===//
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/wait.h>
+
+namespace {
+
+struct ConnectionData_t {
+  int InputPipe;
+  int OutputPipe;
+
+  ConnectionData_t(int in, int out) : InputPipe(in), OutputPipe(out) {}
+};
+
+} // namespace
+
+namespace llvm {
+
+void RemoteTargetExternal::create() {
+  int PipeFD[2][2];
+  pid_t ChildPID;
+
+  pipe(PipeFD[0]);
+  pipe(PipeFD[1]);
+
+  ChildPID = fork();
+
+  if (ChildPID == 0) {
+    // In the child...
+
+    // Close the parent ends of the pipes
+    close(PipeFD[0][1]);
+    close(PipeFD[1][0]);
+
+    // Use our pipes as stdin and stdout
+    if (PipeFD[0][0] != STDIN_FILENO) {
+      dup2(PipeFD[0][0], STDIN_FILENO);
+      close(PipeFD[0][0]);
+    }
+    if (PipeFD[1][1] != STDOUT_FILENO) {
+      dup2(PipeFD[1][1], STDOUT_FILENO);
+      close(PipeFD[1][1]);
+    }
+
+    // Execute the child process.
+    char *args[1] = { NULL };
+    int rc = execv(ChildName.c_str(), args);
+    if (rc != 0)
+      perror("Error executing child process: ");
+  }
+  else {
+    // In the parent...
+
+    // Close the child ends of the pipes
+    close(PipeFD[0][0]);
+    close(PipeFD[1][1]);
+
+    // Store the parent ends of the pipes
+    ConnectionData = (void*)new ConnectionData_t(PipeFD[1][0], PipeFD[0][1]);
+
+    Receive(LLI_ChildActive);
+  }
+}
+
+int RemoteTargetExternal::WriteBytes(const void *Data, size_t Size) {
+  return write(((ConnectionData_t*)ConnectionData)->OutputPipe, Data, Size);
+}
+
+int RemoteTargetExternal::ReadBytes(void *Data, size_t Size) {
+  return read(((ConnectionData_t*)ConnectionData)->InputPipe, Data, Size);
+}
+
+void RemoteTargetExternal::Wait() {
+  wait(NULL);
+}
+
+} // namespace llvm