[llvm] r340003 - [Sparc] Flush register windows for @llvm.returnaddress(1)

[Daniel Cederman via llvm-commits]

Author: dcederman
Date: Fri Aug 17 02:18:31 2018
New Revision: 340003

URL: http://llvm.org/viewvc/llvm-project?rev=340003&view=rev
Log:
[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

Modified:
    llvm/trunk/lib/Target/Sparc/SparcISelLowering.cpp
    llvm/trunk/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll

Modified: llvm/trunk/lib/Target/Sparc/SparcISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Sparc/SparcISelLowering.cpp?rev=340003&r1=340002&r2=340003&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Sparc/SparcISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/Sparc/SparcISelLowering.cpp Fri Aug 17 02:18:31 2018
@@ -2666,7 +2666,8 @@ static SDValue getFLUSHW(SDValue Op, Sel
 }
 
 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 dep
   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 O
   }
 
   // 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,

Modified: llvm/trunk/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll?rev=340003&r1=340002&r2=340003&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll (original)
+++ llvm/trunk/test/CodeGen/SPARC/2011-01-11-FrameAddr.ll Fri Aug 17 02:18:31 2018
@@ -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