[llvm] [Xtensa] Lowering FRAMEADDR/RETURNADDR operations. (PR #107363)
Andrei Safronov via llvm-commits
llvm-commits at lists.llvm.org
Thu Sep 5 01:04:19 PDT 2024
https://github.com/andreisfr created https://github.com/llvm/llvm-project/pull/107363
None
>From 35d700dddec231071e148894c9e360db60fbd8c0 Mon Sep 17 00:00:00 2001
From: Andrei Safronov <safronov at espressif.com>
Date: Thu, 5 Sep 2024 10:59:44 +0300
Subject: [PATCH] [Xtensa] Lowering FRAMEADDR/RETURNADDR operations.
---
llvm/lib/Target/Xtensa/XtensaISelLowering.cpp | 42 +++++++++++++++++++
llvm/lib/Target/Xtensa/XtensaISelLowering.h | 4 ++
.../CodeGen/Xtensa/frameaddr-returnaddr.ll | 23 ++++++++++
3 files changed, 69 insertions(+)
create mode 100644 llvm/test/CodeGen/Xtensa/frameaddr-returnaddr.ll
diff --git a/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp b/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp
index 0d2ce26a942e03..97d9c3e9f9f476 100644
--- a/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp
+++ b/llvm/lib/Target/Xtensa/XtensaISelLowering.cpp
@@ -594,6 +594,26 @@ SDValue XtensaTargetLowering::LowerSELECT_CC(SDValue Op,
FalseValue, TargetCC);
}
+SDValue XtensaTargetLowering::LowerRETURNADDR(SDValue Op,
+ SelectionDAG &DAG) const {
+ // check the depth
+ // TODO: xtensa-gcc can handle this, by navigating through the stack, we
+ // should be able to do this too
+ assert((cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() == 0) &&
+ "Return address can be determined only for current frame.");
+
+ MachineFunction &MF = DAG.getMachineFunction();
+ MachineFrameInfo &MFI = MF.getFrameInfo();
+ EVT VT = Op.getValueType();
+ unsigned RA = Xtensa::A0;
+ MFI.setReturnAddressIsTaken(true);
+
+ // Return RA, which contains the return address. Mark it an implicit
+ // live-in.
+ unsigned Register = MF.addLiveIn(RA, getRegClassFor(MVT::i32));
+ return DAG.getCopyFromReg(DAG.getEntryNode(), SDLoc(Op), Register, VT);
+}
+
SDValue XtensaTargetLowering::LowerImmediate(SDValue Op,
SelectionDAG &DAG) const {
const ConstantSDNode *CN = cast<ConstantSDNode>(Op);
@@ -722,6 +742,24 @@ SDValue XtensaTargetLowering::LowerSTACKRESTORE(SDValue Op,
Op.getOperand(1));
}
+SDValue XtensaTargetLowering::LowerFRAMEADDR(SDValue Op,
+ SelectionDAG &DAG) const {
+ // check the depth
+ assert((cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue() == 0) &&
+ "Frame address can only be determined for current frame.");
+
+ MachineFunction &MF = DAG.getMachineFunction();
+ MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
+ MFI.setFrameAddressIsTaken(true);
+ EVT VT = Op.getValueType();
+ SDLoc DL(Op);
+
+ unsigned FrameRegister = Subtarget.getRegisterInfo()->getFrameRegister(MF);
+ SDValue FrameAddr =
+ DAG.getCopyFromReg(DAG.getEntryNode(), DL, FrameRegister, VT);
+ return FrameAddr;
+}
+
SDValue XtensaTargetLowering::LowerDYNAMIC_STACKALLOC(SDValue Op,
SelectionDAG &DAG) const {
SDValue Chain = Op.getOperand(0); // Legalize the chain.
@@ -867,6 +905,8 @@ SDValue XtensaTargetLowering::LowerOperation(SDValue Op,
return LowerBR_JT(Op, DAG);
case ISD::Constant:
return LowerImmediate(Op, DAG);
+ case ISD::RETURNADDR:
+ return LowerRETURNADDR(Op, DAG);
case ISD::GlobalAddress:
return LowerGlobalAddress(Op, DAG);
case ISD::BlockAddress:
@@ -883,6 +923,8 @@ SDValue XtensaTargetLowering::LowerOperation(SDValue Op,
return LowerSTACKSAVE(Op, DAG);
case ISD::STACKRESTORE:
return LowerSTACKRESTORE(Op, DAG);
+ case ISD::FRAMEADDR:
+ return LowerFRAMEADDR(Op, DAG);
case ISD::DYNAMIC_STACKALLOC:
return LowerDYNAMIC_STACKALLOC(Op, DAG);
case ISD::SHL_PARTS:
diff --git a/llvm/lib/Target/Xtensa/XtensaISelLowering.h b/llvm/lib/Target/Xtensa/XtensaISelLowering.h
index 8e7346b40dfe59..2a878e45047d21 100644
--- a/llvm/lib/Target/Xtensa/XtensaISelLowering.h
+++ b/llvm/lib/Target/Xtensa/XtensaISelLowering.h
@@ -125,12 +125,16 @@ class XtensaTargetLowering : public TargetLowering {
SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
+ SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
+
SDValue LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerSTACKSAVE(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerSTACKRESTORE(SDValue Op, SelectionDAG &DAG) const;
+ SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
+
SDValue LowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
SDValue LowerShiftRightParts(SDValue Op, SelectionDAG &DAG, bool IsSRA) const;
diff --git a/llvm/test/CodeGen/Xtensa/frameaddr-returnaddr.ll b/llvm/test/CodeGen/Xtensa/frameaddr-returnaddr.ll
new file mode 100644
index 00000000000000..057ca03962e520
--- /dev/null
+++ b/llvm/test/CodeGen/Xtensa/frameaddr-returnaddr.ll
@@ -0,0 +1,23 @@
+; RUN: llc -mtriple=xtensa -verify-machineinstrs < %s \
+; RUN: | FileCheck %s
+
+declare ptr @llvm.frameaddress(i32)
+declare ptr @llvm.returnaddress(i32)
+
+define ptr @test_frameaddress_0() nounwind {
+; CHECK-LABEL: test_frameaddress_0:
+; CHECK: # %bb.0:
+; CHECK-NEXT: or a2, a1, a1
+; CHECK-NEXT: ret
+ %1 = call ptr @llvm.frameaddress(i32 0)
+ ret ptr %1
+}
+
+define ptr @test_returnaddress_0() nounwind {
+; CHECK-LABEL: test_returnaddress_0:
+; CHECK: # %bb.0:
+; CHECK-NEXT: or a2, a0, a0
+; CHECK-NEXT: ret
+ %1 = call ptr @llvm.returnaddress(i32 0)
+ ret ptr %1
+}
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