[arm-fast-isel] Add support for ELF PIC.

This is a preliminary step towards ELF support; currently ARMFastISel hasn't
been used for ELF object files yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164759 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMTargetMachine.cpp b/lib/Target/ARM/ARMTargetMachine.cpp
index 133a7dd..42fbc5e 100644
--- a/lib/Target/ARM/ARMTargetMachine.cpp
+++ b/lib/Target/ARM/ARMTargetMachine.cpp
@@ -143,6 +143,11 @@
 
 bool ARMPassConfig::addInstSelector() {
   addPass(createARMISelDag(getARMTargetMachine(), getOptLevel()));
+
+  const ARMSubtarget *Subtarget = &getARMSubtarget();
+  if (Subtarget->isTargetELF() && !Subtarget->isThumb1Only() &&
+      TM->Options.EnableFastISel)
+    addPass(createARMGlobalBaseRegPass());
   return false;
 }