PPC32 va_list is an actual structure so va_copy needs to copy the whole

structure not just a pointer. This implements that and thus fixes va_copy
on PPC32. Fixes #15286. Both bug and patch by Florian Zeitz!

llvm-svn: 187158

3 files changed, 47 insertions, 1 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index fd225ccad56..abb2be67135 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -280,8 +280,13 @@ PPCTargetLowering::PPCTargetLowering(PPCTargetMachine &TM)
   } else
     setOperationAction(ISD::VAARG, MVT::Other, Expand);
 
+  if (Subtarget->isSVR4ABI() && !isPPC64)
+    // VACOPY is custom lowered with the 32-bit SVR4 ABI.
+    setOperationAction(ISD::VACOPY            , MVT::Other, Custom);
+  else
+    setOperationAction(ISD::VACOPY            , MVT::Other, Expand);
+
   // Use the default implementation.
-  setOperationAction(ISD::VACOPY            , MVT::Other, Expand);
   setOperationAction(ISD::VAEND             , MVT::Other, Expand);
   setOperationAction(ISD::STACKSAVE         , MVT::Other, Expand);
   setOperationAction(ISD::STACKRESTORE      , MVT::Other, Custom);
@@ -1650,6 +1655,18 @@ SDValue PPCTargetLowering::LowerVAARG(SDValue Op, SelectionDAG &DAG,
                      false, false, false, 0);
 }
 
+SDValue PPCTargetLowering::LowerVACOPY(SDValue Op, SelectionDAG &DAG,
+                                       const PPCSubtarget &Subtarget) const {
+  assert(!Subtarget.isPPC64() && "LowerVACOPY is PPC32 only");
+
+  // We have to copy the entire va_list struct:
+  // 2*sizeof(char) + 2 Byte alignment + 2*sizeof(char*) = 12 Byte
+  return DAG.getMemcpy(Op.getOperand(0), Op,
+                       Op.getOperand(1), Op.getOperand(2),
+                       DAG.getConstant(12, MVT::i32), 8, false, true,
+                       MachinePointerInfo(), MachinePointerInfo());
+}
+
 SDValue PPCTargetLowering::LowerADJUST_TRAMPOLINE(SDValue Op,
                                                   SelectionDAG &DAG) const {
   return Op.getOperand(0);
@@ -5715,6 +5732,9 @@ SDValue PPCTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::VAARG:
     return LowerVAARG(Op, DAG, PPCSubTarget);
 
+  case ISD::VACOPY:
+    return LowerVACOPY(Op, DAG, PPCSubTarget);
+
   case ISD::STACKRESTORE:       return LowerSTACKRESTORE(Op, DAG, PPCSubTarget);
   case ISD::DYNAMIC_STACKALLOC:
     return LowerDYNAMIC_STACKALLOC(Op, DAG, PPCSubTarget);
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index 776ad2a75ff..1b728a78cda 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -498,6 +498,8 @@ namespace llvm {
                          const PPCSubtarget &Subtarget) const;
     SDValue LowerVAARG(SDValue Op, SelectionDAG &DAG,
                        const PPCSubtarget &Subtarget) const;
+    SDValue LowerVACOPY(SDValue Op, SelectionDAG &DAG,
+                        const PPCSubtarget &Subtarget) const;
     SDValue LowerSTACKRESTORE(SDValue Op, SelectionDAG &DAG,
                                 const PPCSubtarget &Subtarget) const;
     SDValue LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG,
diff --git a/llvm/test/CodeGen/PowerPC/ppc32-vacopy.ll b/llvm/test/CodeGen/PowerPC/ppc32-vacopy.ll
new file mode 100644
index 00000000000..bc394125f13
--- /dev/null
+++ b/llvm/test/CodeGen/PowerPC/ppc32-vacopy.ll
@@ -0,0 +1,24 @@
+; RUN: llc -mtriple="powerpc-unknown-linux-gnu" < %s | FileCheck %s
+; PR15286
+
+%va_list = type {i8, i8, i16, i8*, i8*}
+declare void @llvm.va_copy(i8*, i8*)
+
+define void @test_vacopy() nounwind {
+entry:
+	%0 = alloca %va_list
+	%1 = alloca %va_list
+	%2 = bitcast %va_list* %0 to i8*
+	%3 = bitcast %va_list* %1 to i8*
+
+	call void @llvm.va_copy(i8* %3, i8* %2)
+
+	ret void
+}
+; CHECK: test_vacopy:
+; CHECK: lwz [[REG1:[0-9]+]], {{.*}}
+; CHECK: lwz [[REG2:[0-9]+]], {{.*}}
+; CHECK: lwz [[REG3:[0-9]+]], {{.*}}
+; CHECK: stw [[REG1]], {{.*}}
+; CHECK: stw [[REG2]], {{.*}}
+; CHECK: stw [[REG3]], {{.*}}