Use rip-rel addressing on win64 by default. For this we just
defaults to small pic code model.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111741 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86TargetMachine.cpp b/lib/Target/X86/X86TargetMachine.cpp
index 3c8e7f1..ce8636e 100644
--- a/lib/Target/X86/X86TargetMachine.cpp
+++ b/lib/Target/X86/X86TargetMachine.cpp
@@ -112,15 +112,21 @@
     InstrInfo(*this), JITInfo(*this), TLInfo(*this), TSInfo(*this),
     ELFWriterInfo(*this) {
   DefRelocModel = getRelocationModel();
-      
+
   // If no relocation model was picked, default as appropriate for the target.
   if (getRelocationModel() == Reloc::Default) {
-    if (!Subtarget.isTargetDarwin())
-      setRelocationModel(Reloc::Static);
-    else if (Subtarget.is64Bit())
+    // Darwin defaults to PIC in 64 bit mode and dynamic-no-pic in 32 bit mode.
+    // Win64 requires rip-rel addressing, thus we force it to PIC. Otherwise we
+    // use static relocation model by default.
+    if (Subtarget.isTargetDarwin()) {
+      if (Subtarget.is64Bit())
+        setRelocationModel(Reloc::PIC_);
+      else
+        setRelocationModel(Reloc::DynamicNoPIC);
+    } else if (Subtarget.isTargetWin64())
       setRelocationModel(Reloc::PIC_);
     else
-      setRelocationModel(Reloc::DynamicNoPIC);
+      setRelocationModel(Reloc::Static);
   }
 
   assert(getRelocationModel() != Reloc::Default &&
@@ -143,29 +149,27 @@
       Subtarget.isTargetDarwin() &&
       is64Bit)
     setRelocationModel(Reloc::PIC_);
-      
+
   // Determine the PICStyle based on the target selected.
   if (getRelocationModel() == Reloc::Static) {
     // Unless we're in PIC or DynamicNoPIC mode, set the PIC style to None.
     Subtarget.setPICStyle(PICStyles::None);
+  } else if (Subtarget.is64Bit()) {
+    // PIC in 64 bit mode is always rip-rel.
+    Subtarget.setPICStyle(PICStyles::RIPRel);
   } else if (Subtarget.isTargetCygMing()) {
     Subtarget.setPICStyle(PICStyles::None);
   } else if (Subtarget.isTargetDarwin()) {
-    if (Subtarget.is64Bit())
-      Subtarget.setPICStyle(PICStyles::RIPRel);
-    else if (getRelocationModel() == Reloc::PIC_)
+    if (getRelocationModel() == Reloc::PIC_)
       Subtarget.setPICStyle(PICStyles::StubPIC);
     else {
       assert(getRelocationModel() == Reloc::DynamicNoPIC);
       Subtarget.setPICStyle(PICStyles::StubDynamicNoPIC);
     }
   } else if (Subtarget.isTargetELF()) {
-    if (Subtarget.is64Bit())
-      Subtarget.setPICStyle(PICStyles::RIPRel);
-    else
-      Subtarget.setPICStyle(PICStyles::GOT);
+    Subtarget.setPICStyle(PICStyles::GOT);
   }
-      
+
   // Finally, if we have "none" as our PIC style, force to static mode.
   if (Subtarget.getPICStyle() == PICStyles::None)
     setRelocationModel(Reloc::Static);