[llvm] [ARM64] [Windows] Mark block address as taken when expanding catchrets (PR #109252)

[Maurice Heumann via llvm-commits]

https://github.com/momo5502 created https://github.com/llvm/llvm-project/pull/109252

This fixes issue #109250

The issue happens during the `MachineBlockPlacement` pass. The block, whose address was previously not taken, is deemed redundant by the pass and subsequently replaced using
`MachineBasicBlock::ReplaceUsesOfBlockWith` in `BranchFolding`.

ReplaceUsesOfBlockWith only replaces uses in the terminator. However, `expandPostRAPseudo` introduces new block uses when expanding catchrets. These uses do not get replaced, which results in undefined label errors later on.

Marking the block addresss as taken prevents the replacement of the block, without also replacing non-terminator uses.

>From 694a64136c08084c85d1d12439aa4dfcaa02e981 Mon Sep 17 00:00:00 2001
From: Maurice Heumann <maurice.heumann at wibu.com>
Date: Thu, 19 Sep 2024 10:05:43 +0200
Subject: [PATCH] [ARM64] [Windows] Mark block address as taken when expanding
 catchrets

This fixes issue #109250

The issue happens during the `MachineBlockPlacement` pass.
The block, whose address was previously not taken, is deemed redundant
by the pass and subsequently replaced using
`MachineBasicBlock::ReplaceUsesOfBlockWith` in `BranchFolding`.

ReplaceUsesOfBlockWith only replaces uses in the terminator.
However, `expandPostRAPseudo` introduces new block uses
when expanding catchrets. These uses do not get replaced, which results
in undefined label errors later on.

Marking the block addresss as taken prevents the replacement of the block,
without also replacing non-terminator uses.
---
 llvm/lib/Target/AArch64/AArch64InstrInfo.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
index 3b38a5f78dee51..32bc0e7d0d6475 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
@@ -1994,6 +1994,7 @@ bool AArch64InstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
         .addReg(AArch64::X0)
         .addMBB(TargetMBB)
         .addImm(0);
+    TargetMBB->setMachineBlockAddressTaken();
     return true;
   }