[llvm] [RISCV] Software guard direct calls in large code model (PR #109377)

[Craig Topper via llvm-commits]

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@@ -19736,16 +19739,32 @@ SDValue RISCVTargetLowering::LowerCall(CallLoweringInfo &CLI,
   // Emit the call.
   SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
 
+  // Use software guarded branch for large code model non-indirect calls
+  // Tail call to external symbol will have a null CLI.CB and we need another
+  // way to determine the callsite type
+  bool NeedSWGuarded = false;
+  if (getTargetMachine().getCodeModel() == CodeModel::Large &&
+      Subtarget.hasStdExtZicfilp() &&
+      ((CLI.CB && !CLI.CB->isIndirectCall()) || CalleeIsLargeExternalSymbol))
+    NeedSWGuarded = true;
+
   if (IsTailCall) {
     MF.getFrameInfo().setHasTailCall();
-    SDValue Ret = DAG.getNode(RISCVISD::TAIL, DL, NodeTys, Ops);
+    SDValue Ret;
+    if (NeedSWGuarded)
+      Ret = DAG.getNode(RISCVISD::SW_GUARDED_TAIL, DL, NodeTys, Ops);
+    else
+      Ret = DAG.getNode(RISCVISD::TAIL, DL, NodeTys, Ops);
     if (CLI.CFIType)
       Ret.getNode()->setCFIType(CLI.CFIType->getZExtValue());
     DAG.addNoMergeSiteInfo(Ret.getNode(), CLI.NoMerge);
     return Ret;
   }
 
-  Chain = DAG.getNode(RISCVISD::CALL, DL, NodeTys, Ops);
+  if (NeedSWGuarded)
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topperc wrote:

Select the opcode instead of repeating the getNode call.

https://github.com/llvm/llvm-project/pull/109377