Add ARM fast-isel support for materializing the address of a global in cases where the global uses an indirect symbol.

rdar://9431157



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132522 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index ed95868..bcfa5c5 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -577,9 +577,6 @@
 
   Reloc::Model RelocM = TM.getRelocationModel();
 
-  // TODO: No external globals for now.
-  if (Subtarget->GVIsIndirectSymbol(GV, RelocM)) return 0;
-
   // TODO: Need more magic for ARM PIC.
   if (!isThumb && (RelocM == Reloc::PIC_)) return 0;
 
@@ -614,6 +611,23 @@
           .addImm(0);
   }
   AddOptionalDefs(MIB);
+
+  if (Subtarget->GVIsIndirectSymbol(GV, RelocM)) {
+    unsigned NewDestReg = createResultReg(TLI.getRegClassFor(VT));
+    if (isThumb)
+      MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(ARM::t2LDRi12),
+                    NewDestReg)
+            .addReg(DestReg)
+            .addImm(0);
+    else
+      MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DL, TII.get(ARM::LDRi12),
+                    NewDestReg)
+            .addReg(DestReg)
+            .addImm(0);
+    DestReg = NewDestReg;
+    AddOptionalDefs(MIB);
+  }
+
   return DestReg;
 }