[PowerPC] Load BlockAddress values from the TOC in 64-bit SVR4 code

Since block address values can be larger than 2GB in 64-bit code, they
cannot be loaded simply using an @l / @ha pair, but instead must be
loaded from the TOC, just like GlobalAddress, ConstantPool, and
JumpTable values are.

The commit also fixes a bug in PPCLinuxAsmPrinter::doFinalization where
temporary labels could not be used as TOC values, since code would
attempt (and fail) to use GetOrCreateSymbol to create a symbol of the
same name as the temporary label.

llvm-svn: 220959

1 files changed, 9 insertions, 1 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 72d3a59192b..c9e2802f7ad 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1638,8 +1638,16 @@ SDValue PPCTargetLowering::LowerJumpTable(SDValue Op, SelectionDAG &DAG) const {
 SDValue PPCTargetLowering::LowerBlockAddress(SDValue Op,
                                              SelectionDAG &DAG) const {
   EVT PtrVT = Op.getValueType();
+  BlockAddressSDNode *BASDN = cast<BlockAddressSDNode>(Op);
+  const BlockAddress *BA = BASDN->getBlockAddress();
 
-  const BlockAddress *BA = cast<BlockAddressSDNode>(Op)->getBlockAddress();
+  // 64-bit SVR4 ABI code is always position-independent.
+  // The actual BlockAddress is stored in the TOC.
+  if (Subtarget.isSVR4ABI() && Subtarget.isPPC64()) {
+    SDValue GA = DAG.getTargetBlockAddress(BA, PtrVT, BASDN->getOffset());
+    return DAG.getNode(PPCISD::TOC_ENTRY, SDLoc(BASDN), MVT::i64, GA,
+                       DAG.getRegister(PPC::X2, MVT::i64));
+  }
 
   unsigned MOHiFlag, MOLoFlag;
   bool isPIC = GetLabelAccessInfo(DAG.getTarget(), MOHiFlag, MOLoFlag);