[SystemZ] Add stack protector TLS slot.

[• koriakin]

Summary

This fixes PR22248 on s390x. Depends on D19054.

[uweigand]

LGTM once the dependencies are in.

[• koriakin]

Since D19141 has just introduced a new way to do SSP, I'll attempt to convert this patch to the new path.

[• koriakin]

Abandoning getIRStackGuard-based version in favor of D19363.

lib/Target/SystemZ/SystemZISelLowering.h

public:
   SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool IsVarArg,
                       const SmallVectorImpl<ISD::OutputArg> &Outs,
                       const SmallVectorImpl<SDValue> &OutVals,
                       SDLoc DL, SelectionDAG &DAG) const override;
   SDValue prepareVolatileOrAtomicLoad(SDValue Chain, SDLoc DL,
                                       SelectionDAG &DAG) const override;
   SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
 
+  /// If the target has a standard location for the stack protector cookie,
+  /// returns the address of that location. Otherwise, returns nullptr.
+  Value *getIRStackGuard(IRBuilder<> &IRB) const override;
+
 private:
   const SystemZSubtarget &Subtarget;
 
   // Implement LowerOperation for individual opcodes.
   SDValue lowerSETCC(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
   SDValue lowerGlobalAddress(GlobalAddressSDNode *Node,

lib/Target/SystemZ/SystemZISelLowering.cpp

if (N->getValueType(0) == MVT::f32 &&
           }
         }
       }
     }
   }
   return SDValue();
 }
 
+Value *SystemZTargetLowering::getIRStackGuard(IRBuilder<> &IRB) const {
+  const unsigned TlsOffset = 0x28;
+  Module *M = IRB.GetInsertBlock()->getParent()->getParent();
+  Function *ThreadPointerFunc =
+      Intrinsic::getDeclaration(M, Intrinsic::thread_pointer);
+  return IRB.CreatePointerCast(
+      IRB.CreateConstGEP1_32(IRB.CreateCall(ThreadPointerFunc), TlsOffset),
+      Type::getInt8PtrTy(IRB.getContext())->getPointerTo(0));
+}
+
 //===----------------------------------------------------------------------===//
 // Custom insertion
 //===----------------------------------------------------------------------===//
 
 // Create a new basic block after MBB.
 static MachineBasicBlock *emitBlockAfter(MachineBasicBlock *MBB) {
   MachineFunction &MF = *MBB->getParent();
   MachineBasicBlock *NewMBB = MF.CreateMachineBasicBlock(MBB->getBasicBlock());

test/CodeGen/SystemZ/stack-guard.ll

+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
+
+; CHECK-LABEL: @test_stack_guard
+; CHECK: ear [[REG1:%r[0-9]*]], %a0
+; CHECK: sllg [[REG2:%r[0-9]*]], [[REG1]], 32
+; CHECK: ear [[REG2]], %a1
+; CHECK: lg [[REG3:%r[0-9]*]], 40([[REG2]])
+; CHECK: stg [[REG3]], {{[0-9]*}}(%r15)
+; CHECK: brasl %r14, foo3@PLT
+; CHECK: lg [[REG4:%r[0-9]*]], 40([[REG2]])
+; CHECK: cg [[REG4]], {{[0-9]*}}(%r15)
+
+define i32 @test_stack_guard() #0 {
+entry:
+  %a1 = alloca [256 x i32], align 4
+  %0 = bitcast [256 x i32]* %a1 to i8*
+  call void @llvm.lifetime.start(i64 1024, i8* %0)
+  %arraydecay = getelementptr inbounds [256 x i32], [256 x i32]* %a1, i64 0, i64 0
+  call void @foo3(i32* %arraydecay)
+  call void @llvm.lifetime.end(i64 1024, i8* %0)
+  ret i32 0
+}
+
+; Function Attrs: nounwind
+declare void @llvm.lifetime.start(i64, i8* nocapture)
+
+declare void @foo3(i32*)
+
+; Function Attrs: nounwind
+declare void @llvm.lifetime.end(i64, i8* nocapture)
+
+attributes #0 = { sspstrong }