Reorganize llvmc code.

Move the code from 'llvmc/driver' into a new CompilerDriver library, and change
the build system accordingly. Makes it easier for projects using LLVM to build
their own llvmc-based drivers.

Tested with objdir != srcdir.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65821 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CompilerDriver/Action.cpp

@@ -0,0 +1,78 @@
+//===--- Action.cpp - The LLVM Compiler Driver ------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open
+// Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  Action class - implementation and auxiliary functions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CompilerDriver/Action.h"
+
+#include "llvm/Support/CommandLine.h"
+#include "llvm/System/Program.h"
+
+#include <iostream>
+#include <stdexcept>
+
+using namespace llvm;
+using namespace llvmc;
+
+extern cl::opt<bool> DryRun;
+extern cl::opt<bool> VerboseMode;
+
+namespace {
+  int ExecuteProgram(const std::string& name,
+                     const StrVector& args) {
+    sys::Path prog = sys::Program::FindProgramByName(name);
+
+    if (prog.isEmpty())
+      throw std::runtime_error("Can't find program '" + name + "'");
+    if (!prog.canExecute())
+      throw std::runtime_error("Program '" + name + "' is not executable.");
+
+    // Build the command line vector and the redirects array.
+    const sys::Path* redirects[3] = {0,0,0};
+    sys::Path stdout_redirect;
+
+    std::vector<const char*> argv;
+    argv.reserve((args.size()+2));
+    argv.push_back(name.c_str());
+
+    for (StrVector::const_iterator B = args.begin(), E = args.end();
+         B!=E; ++B) {
+      if (*B == ">") {
+        ++B;
+        stdout_redirect.set(*B);
+        redirects[1] = &stdout_redirect;
+      }
+      else {
+        argv.push_back((*B).c_str());
+      }
+    }
+    argv.push_back(0);  // null terminate list.
+
+    // Invoke the program.
+    return sys::Program::ExecuteAndWait(prog, &argv[0], 0, &redirects[0]);
+  }
+
+  void print_string (const std::string& str) {
+    std::cerr << str << ' ';
+  }
+}
+
+int llvmc::Action::Execute() const {
+  if (DryRun || VerboseMode) {
+    std::cerr << Command_ << " ";
+    std::for_each(Args_.begin(), Args_.end(), print_string);
+    std::cerr << '\n';
+  }
+  if (DryRun)
+    return 0;
+  else
+    return ExecuteProgram(Command_, Args_);
+}