commit 3ee2af7d1c0decb43729d239b5c6c0052b5308b7
author Hal Finkel <hfinkel@anl.gov> Fri Jul 18 23:29:49 2014 +0000
committer Hal Finkel <hfinkel@anl.gov> Fri Jul 18 23:29:49 2014 +0000
tree ed2c775d579da6195162e9146eea3a83c8e0d678
parent 8924d27c02b546d1f4da3be97b353792df4e6211

[PowerPC] 32-bit ELF PIC support

This adds initial support for PPC32 ELF PIC (Position Independent Code; the
-fPIC variety), thus rectifying a long-standing deficiency in the PowerPC
backend.

Patch by Justin Hibbits!

llvm-svn: 213427

llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp

diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 4881b3f..a9e1462 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -14,6 +14,7 @@
 
 #include "PPC.h"
 #include "MCTargetDesc/PPCPredicates.h"
+#include "PPCMachineFunctionInfo.h"
 #include "PPCTargetMachine.h"
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
@@ -275,9 +276,21 @@
     DebugLoc dl;
 
     if (PPCLowering->getPointerTy() == MVT::i32) {
-      GlobalBaseReg = RegInfo->createVirtualRegister(&PPC::GPRC_NOR0RegClass);
+      if (PPCSubTarget->isTargetELF())
+        GlobalBaseReg = PPC::R30;
+      else
+        GlobalBaseReg =
+          RegInfo->createVirtualRegister(&PPC::GPRC_NOR0RegClass);
       BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MovePCtoLR));
       BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MFLR), GlobalBaseReg);
+      if (PPCSubTarget->isTargetELF()) {
+        unsigned TempReg = RegInfo->createVirtualRegister(&PPC::GPRCRegClass);
+        BuildMI(FirstMBB, MBBI, dl,
+                TII.get(PPC::GetGBRO), TempReg).addReg(GlobalBaseReg);
+        BuildMI(FirstMBB, MBBI, dl,
+                TII.get(PPC::UpdateGBR)).addReg(GlobalBaseReg).addReg(TempReg);
+        MF->getInfo<PPCFunctionInfo>()->setUsesPICBase(true);
+      }
     } else {
       GlobalBaseReg = RegInfo->createVirtualRegister(&PPC::G8RC_NOX0RegClass);
       BuildMI(FirstMBB, MBBI, dl, TII.get(PPC::MovePCtoLR8));
@@ -1445,7 +1458,13 @@
     return CurDAG->SelectNodeTo(N, Reg, MVT::Other, Chain);
   }
   case PPCISD::TOC_ENTRY: {
-    assert (PPCSubTarget->isPPC64() && "Only supported for 64-bit ABI");
+    if (PPCSubTarget->isSVR4ABI() && !PPCSubTarget->isPPC64()) {
+      SDValue GA = N->getOperand(0);
+      return CurDAG->getMachineNode(PPC::LWZtoc, dl, MVT::i32, GA,
+                                    N->getOperand(1));
+	}
+    assert (PPCSubTarget->isPPC64() &&
+            "Only supported for 64-bit ABI and 32-bit SVR4");
 
     // For medium and large code model, we generate two instructions as
     // described below.  Otherwise we allow SelectCodeCommon to handle this,