[compiler-rt] [flang] [llvm] [AArch64] fix trampoline implementation: use X15 (PR #126743)

[Slava Zakharin via llvm-commits]

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@@ -7290,59 +7290,80 @@ static SDValue LowerFLDEXP(SDValue Op, SelectionDAG &DAG) {
 
 SDValue AArch64TargetLowering::LowerADJUST_TRAMPOLINE(SDValue Op,
                                                       SelectionDAG &DAG) const {
-  // Note: x18 cannot be used for the Nest parameter on Windows and macOS.
-  if (Subtarget->isTargetDarwin() || Subtarget->isTargetWindows())
-    report_fatal_error(
-        "ADJUST_TRAMPOLINE operation is only supported on Linux.");
-
   return Op.getOperand(0);
 }
 
 SDValue AArch64TargetLowering::LowerINIT_TRAMPOLINE(SDValue Op,
                                                     SelectionDAG &DAG) const {
-
-  // Note: x18 cannot be used for the Nest parameter on Windows and macOS.
-  if (Subtarget->isTargetDarwin() || Subtarget->isTargetWindows())
-    report_fatal_error("INIT_TRAMPOLINE operation is only supported on Linux.");
-
   SDValue Chain = Op.getOperand(0);
-  SDValue Trmp = Op.getOperand(1); // trampoline
+  SDValue Trmp = Op.getOperand(1); // trampoline, 36 bytes
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vzakhari wrote:

Thanks for explaining the trampoline size above. Please update `36` here accordingly.

https://github.com/llvm/llvm-project/pull/126743