[PATCH] D125916: [PowerPC] Defined and lowered llvm.ppc.kill.canary intrinsic

[Paul Scoropan via Phabricator via llvm-commits]

pscoro created this revision.
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Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D125916

Files:
  llvm/include/llvm/IR/IntrinsicsPowerPC.td
  llvm/lib/Target/PowerPC/PPCISelLowering.cpp


Index: llvm/lib/Target/PowerPC/PPCISelLowering.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -11103,6 +11103,43 @@
     }
     break;
   }
+  case Intrinsic::ppc_kill_canary: {
+    MachineFunction &MF = DAG.getMachineFunction();
+    if (MF.getFunction().hasFnAttribute(Attribute::SafeStack)) {
+	break;
+    }
+
+    MachineFrameInfo &MFI = MF.getFrameInfo();
+    int SPI = MFI.getStackProtectorIndex(); // should return  -1
+    
+    PPCFunctionInfo *FuncInfo = MF.getInfo<PPCFunctionInfo>();
+    EVT PtrVT = getPointerTy(MF.getDataLayout());
+    SDValue FIN = DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(), PtrVT); // frame index
+
+    unsigned int deadBird = 0x4C6C566D; // replaces canary word
+
+    SDValue Store = DAG.getStore( // create store instr, stores (deadBird + 0) into addr (frame index + stack protector)
+            Op->getOperand(0), 
+            DL,
+	    DAG.getNode( // add deadBird, 0, return node result
+		    ISD::ADD,
+		    DL, 
+		    PtrVT, 
+		    DAG.getConstant(deadBird, DL, PtrVT), 
+		    DAG.getConstant(0, DL, PtrVT) 
+            ),
+            DAG.getNode( // add frame index, stack protector index, return node result
+                    ISD::ADD,
+                    DL,      
+                    PtrVT,    
+                    FIN,       
+                    DAG.getConstant(SPI, DL, PtrVT)
+            ), 
+            MachinePointerInfo() 
+    );
+    return Store;
+    break;
+  }
   default:
     break;
   }
Index: llvm/include/llvm/IR/IntrinsicsPowerPC.td
===================================================================
--- llvm/include/llvm/IR/IntrinsicsPowerPC.td
+++ llvm/include/llvm/IR/IntrinsicsPowerPC.td
@@ -217,6 +217,10 @@
       : Intrinsic<[llvm_float_ty],
                   [llvm_float_ty, llvm_float_ty, llvm_float_ty, llvm_vararg_ty],
                   [IntrNoMem]>;
+  def int_ppc_kill_canary
+      : Intrinsic<[],
+                  [],
+                  [IntrWriteMem, IntrHasSideEffects]>;
 }
 
 let TargetPrefix = "ppc" in {  // All PPC intrinsics start with "llvm.ppc.".


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