Driver/Darwin: Pass -pie/-no_pie to the linker when -fpie/-fno-pie and friends
are explicitly given.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108297 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/ArgList.cpp b/lib/Driver/ArgList.cpp
index 95fef89..9101523 100644
--- a/lib/Driver/ArgList.cpp
+++ b/lib/Driver/ArgList.cpp
@@ -95,6 +95,25 @@
   return Res;
 }
 
+Arg *ArgList::getLastArg(OptSpecifier Id0, OptSpecifier Id1,
+                         OptSpecifier Id2, OptSpecifier Id3) const {
+  Arg *Res = 0;
+  for (const_reverse_iterator it = rbegin(), ie = rend(); it != ie; ++it) {
+    if ((*it)->getOption().matches(Id0) ||
+        (*it)->getOption().matches(Id1) ||
+        (*it)->getOption().matches(Id2) ||
+        (*it)->getOption().matches(Id3)) {
+      Res = *it;
+      break;
+    }
+  }
+
+  if (Res)
+    Res->claim();
+
+  return Res;
+}
+
 bool ArgList::hasFlag(OptSpecifier Pos, OptSpecifier Neg, bool Default) const {
   if (Arg *A = getLastArg(Pos, Neg))
     return A->getOption().matches(Pos);
diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
index 9e03a18..e6465ac 100644
--- a/lib/Driver/Tools.cpp
+++ b/lib/Driver/Tools.cpp
@@ -2356,8 +2356,15 @@
   Args.AddAllArgs(CmdArgs, options::OPT_multiply__defined);
   Args.AddAllArgs(CmdArgs, options::OPT_multiply__defined__unused);
 
-  if (Args.hasArg(options::OPT_fpie))
-    CmdArgs.push_back("-pie");
+  if (const Arg *A = Args.getLastArg(options::OPT_fpie, options::OPT_fPIE,
+                                     options::OPT_fno_pie,
+                                     options::OPT_fno_PIE)) {
+    if (A->getOption().matches(options::OPT_fpie) ||
+        A->getOption().matches(options::OPT_fPIE))
+      CmdArgs.push_back("-pie");
+    else
+      CmdArgs.push_back("-no_pie");
+  }
 
   Args.AddLastArg(CmdArgs, options::OPT_prebind);
   Args.AddLastArg(CmdArgs, options::OPT_noprebind);