[Sparc] Flush register windows for @llvm.returnaddress(1)

Summary: When @llvm.returnaddress is called with a value higher than 0 it needs to read from the call stack to get the return address. This means that the register windows needs to be flushed to the stack to guarantee that the data read is valid. For values higher than 1 this is done indirectly by the call to getFRAMEADDR(), but not for the value 1. Reviewers: jyknight, venkatra Reviewed By: jyknight Subscribers: fedor.sergeev, jrtc27, llvm-commits Differential Revision: https://reviews.llvm.org/D48636 llvm-svn: 340003
llvm · Aug 17, 2018 · 7d3e08f · 7d3e08f
1 parent 4c0c37d
commit 7d3e08f
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Showing 2 changed files with 24 additions and 11 deletions.
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -2666,7 +2666,8 @@ static SDValue getFLUSHW(SDValue Op, SelectionDAG &DAG) {
 }
 
 static SDValue getFRAMEADDR(uint64_t depth, SDValue Op, SelectionDAG &DAG,
-                            const SparcSubtarget *Subtarget) {
+                            const SparcSubtarget *Subtarget,
+                            bool AlwaysFlush = false) {
   MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
   MFI.setFrameAddressIsTaken(true);
 
@@ -2676,17 +2677,11 @@ static SDValue getFRAMEADDR(uint64_t depth, SDValue Op, SelectionDAG &DAG,
   unsigned stackBias = Subtarget->getStackPointerBias();
 
   SDValue FrameAddr;
-
-  if (depth == 0) {
-    FrameAddr = DAG.getCopyFromReg(DAG.getEntryNode(), dl, FrameReg, VT);
-    if (Subtarget->is64Bit())
-      FrameAddr = DAG.getNode(ISD::ADD, dl, VT, FrameAddr,
-                              DAG.getIntPtrConstant(stackBias, dl));
-    return FrameAddr;
-  }
+  SDValue Chain;
 
   // flush first to make sure the windowed registers' values are in stack
-  SDValue Chain = getFLUSHW(Op, DAG);
+  Chain = (depth || AlwaysFlush) ? getFLUSHW(Op, DAG) : DAG.getEntryNode();
+
   FrameAddr = DAG.getCopyFromReg(Chain, dl, FrameReg, VT);
 
   unsigned Offset = (Subtarget->is64Bit()) ? (stackBias + 112) : 56;
@@ -2735,7 +2730,7 @@ static SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG,
   }
 
   // Need frame address to find return address of the caller.
-  SDValue FrameAddr = getFRAMEADDR(depth - 1, Op, DAG, Subtarget);
+  SDValue FrameAddr = getFRAMEADDR(depth - 1, Op, DAG, Subtarget, true);
 
   unsigned Offset = (Subtarget->is64Bit()) ? 120 : 60;
   SDValue Ptr = DAG.getNode(ISD::ADD,

diff --git a/llvm/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll b/llvm/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll
@@ -96,4 +96,22 @@ entry:
   ret i8* %0
 }
 
+define i8* @retaddr3() nounwind readnone {
+entry:
+;V8-LABEL: retaddr3:
+;V8: ta 3
+;V8: ld [%fp+60], {{.+}}
+
+;V9-LABEL: retaddr3:
+;V9: flushw
+;V9: ld [%fp+60], {{.+}}
+
+;SPARC64-LABEL: retaddr3
+;SPARC64:       flushw
+;SPARC64: ldx [%fp+2167],     %[[R0:[goli][0-7]]]
+
+  %0 = tail call i8* @llvm.returnaddress(i32 1)
+  ret i8* %0
+}
+
 declare i8* @llvm.returnaddress(i32) nounwind readnone