Support for VAARG. As noted in a comment, this is

wrong for types like x86 long double and i1, but
no worse than what is done in LegalizeDAG.

llvm-svn: 52898

2 files changed, 33 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
index cf98b3c9d18..1a97dcaf586 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
@@ -84,6 +84,8 @@ void DAGTypeLegalizer::PromoteIntegerResult(SDNode *N, unsigned ResNo) {
   case ISD::EXTRACT_VECTOR_ELT:
     Result = PromoteIntRes_EXTRACT_VECTOR_ELT(N);
     break;
+
+  case ISD::VAARG : Result = PromoteIntRes_VAARG(N); break;
   }
 
   // If Result is null, the sub-method took care of registering the result.
@@ -411,6 +413,36 @@ SDOperand DAGTypeLegalizer::PromoteIntRes_EXTRACT_VECTOR_ELT(SDNode *N) {
   return DAG.getNode(ISD::SELECT, NewVT, Odd, Hi, Lo);
 }
 
+SDOperand DAGTypeLegalizer::PromoteIntRes_VAARG(SDNode *N) {
+  SDOperand Chain = N->getOperand(0); // Get the chain.
+  SDOperand Ptr = N->getOperand(1); // Get the pointer.
+  MVT VT = N->getValueType(0);
+
+  const Value *V = cast<SrcValueSDNode>(N->getOperand(2))->getValue();
+  SDOperand VAList = DAG.getLoad(TLI.getPointerTy(), Chain, Ptr, V, 0);
+
+  // Increment the arg pointer, VAList, to the next vaarg
+  // FIXME: should the ABI size be used for the increment?  Think of
+  // x86 long double (10 bytes long, but aligned on 4 or 8 bytes) or
+  // integers of unusual size (such MVT::i1, which gives an increment
+  // of zero here!).
+  unsigned Increment = VT.getSizeInBits() / 8;
+  SDOperand Tmp = DAG.getNode(ISD::ADD, TLI.getPointerTy(), VAList,
+                              DAG.getConstant(Increment, TLI.getPointerTy()));
+
+  // Store the incremented VAList to the pointer.
+  Tmp = DAG.getStore(VAList.getValue(1), Tmp, Ptr, V, 0);
+
+  // Load the actual argument out of the arg pointer VAList.
+  Tmp = DAG.getExtLoad(ISD::EXTLOAD, TLI.getTypeToTransformTo(VT), Tmp,
+                       VAList, NULL, 0, VT);
+
+  // Legalized the chain result - switch anything that used the old chain to
+  // use the new one.
+  ReplaceValueWith(SDOperand(N, 1), Tmp.getValue(1));
+  return Tmp;
+}
+
 //===----------------------------------------------------------------------===//
 //  Integer Operand Promotion
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index 6b9d1abed1e..13a10f7365d 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -234,6 +234,7 @@ private:
   SDOperand PromoteIntRes_TRUNCATE(SDNode *N);
   SDOperand PromoteIntRes_UDIV(SDNode *N);
   SDOperand PromoteIntRes_UNDEF(SDNode *N);
+  SDOperand PromoteIntRes_VAARG(SDNode *N);
 
   // Integer Operand Promotion.
   bool PromoteIntegerOperand(SDNode *N, unsigned OperandNo);