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[AArch64] Add missing SEH_Nop when aligning the stack 

This makes sure that the instructions of the prologue matches the
SEH opcodes.

Also remove a couple redundant cases of setting HasWinCFI; it was
already set unconditionally after the conditional cases.

Differential Revision: https://reviews.llvm.org/D135101
This commit is contained in:
Martin Storsjö 2022-10-01 15:30:25 +03:00
parent a9ffb47345
commit 2f7fbf8376
2 changed files with 30 additions and 4 deletions
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7
llvm/lib/Target/AArch64/AArch64InstrInfo.cpp
View File

@ -4334,8 +4334,6 @@ static void emitFrameOffsetAdj(MachineBasicBlock &MBB,
int Imm = (int)(ThisVal << LocalShiftSize);
if ((DestReg == AArch64::FP && SrcReg == AArch64::SP) ||
(SrcReg == AArch64::FP && DestReg == AArch64::SP)) {
if (HasWinCFI)
*HasWinCFI = true;
if (Imm == 0)
BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_SetFP)).setMIFlag(Flag);
else
@ -4345,12 +4343,13 @@ static void emitFrameOffsetAdj(MachineBasicBlock &MBB,
assert(Offset == 0 && "Expected remaining offset to be zero to "
"emit a single SEH directive");
} else if (DestReg == AArch64::SP) {
if (HasWinCFI)
*HasWinCFI = true;
assert(SrcReg == AArch64::SP && "Unexpected SrcReg for SEH_StackAlloc");
BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_StackAlloc))
.addImm(Imm)
.setMIFlag(Flag);
} else {
BuildMI(MBB, MBBI, DL, TII->get(AArch64::SEH_Nop))
.setMIFlag(Flag);
}
if (HasWinCFI)
*HasWinCFI = true;

27
llvm/test/CodeGen/AArch64/wineh-align-stack.ll Normal file
View File

@ -0,0 +1,27 @@
; RUN: llc < %s -mtriple=aarch64-windows | FileCheck %s
define dso_local void @func() {
entry:
%buf = alloca [64 x i8], align 32
%arraydecay = getelementptr inbounds [64 x i8], ptr %buf, i64 0, i64 0
call void @other(ptr noundef %arraydecay)
ret void
}
declare dso_local void @other(ptr noundef)
; CHECK-LABEL: func:
; CHECK-NEXT: .seh_proc func
; CHECK-NEXT: // %bb.0:
; CHECK-NEXT: stp x29, x30, [sp, #-16]!
; CHECK-NEXT: .seh_save_fplr_x 16
; CHECK-NEXT: mov x29, sp
; CHECK-NEXT: .seh_set_fp
; CHECK-NEXT: sub x9, sp, #80
; CHECK-NEXT: .seh_nop
; CHECK-NEXT: and sp, x9, #0xffffffffffffffe0
; CHECK-NEXT: .seh_stackalloc 80
; CHECK-NEXT: .seh_endprologue
; FIXME: Ideally, the SEH prologue wouldn't include the stack realigning
; instructions at all, but it's enough to end the prologue after .seh_set_fp.