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[ARM64] [Windows] Mark block address as taken when expanding catchrets
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This fixes issue llvm#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.
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momo5502 committed Sep 19, 2024
1 parent 4c50112 commit 2d894bd
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Showing 3 changed files with 4 additions and 2 deletions.
1 change: 1 addition & 0 deletions llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -1994,6 +1994,7 @@ bool AArch64InstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
.addReg(AArch64::X0)
.addMBB(TargetMBB)
.addImm(0);
TargetMBB->setMachineBlockAddressTaken();
return true;
}

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3 changes: 2 additions & 1 deletion llvm/test/CodeGen/AArch64/pr58516.ll
Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,8 @@ define void @osfx(ptr %this) comdat personality ptr @__CxxFrameHandler3 {
; CHECK-NEXT: // %bb.1: // %invoke.cont12
; CHECK-NEXT: str wzr, [x20]
; CHECK-NEXT: str wzr, [x21]
; CHECK-NEXT: .LBB0_2: // %try.cont
; CHECK-NEXT: .LBB0_2: // Block address taken
; CHECK-NEXT: // %try.cont
; CHECK-NEXT: $ehgcr_0_2:
; CHECK-NEXT: .seh_startepilogue
; CHECK-NEXT: sub sp, x29, #24
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2 changes: 1 addition & 1 deletion llvm/test/CodeGen/AArch64/wineh-try-catch.ll
Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@
; CHECK-LABEL: .Ltmp0:
; CHECK: bl "?func2@@YAHXZ

; CHECK: [[CATCHRETDEST:.LBB0_[0-9]+]]: // %catchret.dest
; CHECK: [[CATCHRETDEST:.LBB0_[0-9]+]]: // Block address taken

; Check the catch funclet.
; CHECK-LABEL: "?catch$4@?0??func@@YAHXZ@4HA":
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