[PATCH] D126872: [ARM] Fix restoring stack for varargs with SEH split frame pointer push

[Martin Storsjö via Phabricator via llvm-commits]

mstorsjo created this revision.
mstorsjo added reviewers: efriedma, zzheng.
Herald added subscribers: hiraditya, kristof.beyls.
Herald added a project: All.
mstorsjo requested review of this revision.
Herald added a project: LLVM.

Previously, the "add sp, #12" ended up inserted after "bx lr".


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D126872

Files:
  llvm/lib/Target/ARM/ARMFrameLowering.cpp
  llvm/test/CodeGen/ARM/Windows/wineh-framepointer.ll


Index: llvm/test/CodeGen/ARM/Windows/wineh-framepointer.ll
===================================================================
--- llvm/test/CodeGen/ARM/Windows/wineh-framepointer.ll
+++ llvm/test/CodeGen/ARM/Windows/wineh-framepointer.ll
@@ -60,3 +60,68 @@
 declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture)
 
 declare arm_aapcs_vfpcc void @other(i32 noundef, ptr noundef, ptr noundef)
+
+; CHECK-LABEL: everything_varargs:
+; CHECK-NEXT: .seh_proc everything_varargs
+; CHECK-NEXT: @ %bb.0:                                @ %entry
+; CHECK-NEXT:         sub     sp, #12
+; CHECK-NEXT:         .seh_stackalloc 12
+; CHECK-NEXT:         push.w  {r4, r5, r6, r7, r8, r9}
+; CHECK-NEXT:         .seh_save_regs_w        {r4-r9}
+; CHECK-NEXT:         sub     sp, #4
+; CHECK-NEXT:         .seh_stackalloc 4
+; CHECK-NEXT:         vpush   {d8, d9, d10, d11, d12, d13, d14, d15}
+; CHECK-NEXT:         .seh_save_fregs         {d8-d15}
+; CHECK-NEXT:         push.w  {r11, lr}
+; CHECK-NEXT:         .seh_save_regs_w        {r11, lr}
+; CHECK-NEXT:         mov     r11, sp
+; CHECK-NEXT:         .seh_save_sp    r11
+; CHECK-NEXT:         .seh_endprologue
+; CHECK-NEXT:         movw    r4, #1258
+; CHECK-NEXT:         bl      __chkstk
+; CHECK-NEXT:         sub.w   sp, sp, r4
+; CHECK-NEXT:         mov     r4, sp
+; CHECK-NEXT:         bfc     r4, #0, #4
+; CHECK-NEXT:         mov     sp, r4
+
+; CHECK:              .seh_startepilogue
+; CHECK-NEXT:         mov     sp, r11
+; CHECK-NEXT:         .seh_save_sp    r11
+; CHECK-NEXT:         pop.w   {r11, lr}
+; CHECK-NEXT:         .seh_save_regs_w        {r11, lr}
+; CHECK-NEXT:         vpop    {d8, d9, d10, d11, d12, d13, d14, d15}
+; CHECK-NEXT:         .seh_save_fregs         {d8-d15}
+; CHECK-NEXT:         add     sp, #4
+; CHECK-NEXT:         .seh_stackalloc 4
+; CHECK-NEXT:         pop.w   {r4, r5, r6, r7, r8, r9}
+; CHECK-NEXT:         .seh_save_regs_w        {r4-r9}
+; CHECK-NEXT:         add     sp, #12
+; CHECK-NEXT:         .seh_stackalloc 12
+; CHECK-NEXT:         bx      lr
+; CHECK-NEXT:         .seh_nop
+; CHECK-NEXT:         .seh_endepilogue
+; CHECK-NEXT:         .seh_endproc
+
+define arm_aapcs_vfpcc void @everything_varargs(i32 noundef %a, ...) {
+entry:
+  %buf2 = alloca [5000 x i8], align 16
+  %ap = alloca ptr, align 4
+  %vla = alloca i8, i32 %a, align 1
+  call void @llvm.lifetime.start.p0(i64 5000, ptr nonnull %buf2)
+  call void @llvm.lifetime.start.p0(i64 4, ptr nonnull %ap)
+  call void @llvm.va_start(ptr nonnull %ap)
+  %0 = load ptr, ptr %ap, align 4
+  call arm_aapcs_vfpcc void @other2(i32 noundef %a, ptr noundef nonnull %vla, ptr noundef nonnull %buf2, ptr noundef %0)
+  call void @llvm.va_end(ptr nonnull %ap)
+  call void asm sideeffect "", "~{r4},~{r5},~{r6},~{r7},~{r8},~{r9},~{r11},~{r12}"()
+  call void asm sideeffect "", "~{d8},~{d9},~{d10},~{d11},~{d12},~{d13},~{d14},~{d15}"()
+  call void @llvm.lifetime.end.p0(i64 4, ptr nonnull %ap)
+  call void @llvm.lifetime.end.p0(i64 5000, ptr nonnull %buf2)
+  ret void
+}
+
+
+declare void @llvm.va_start(ptr)
+declare void @llvm.va_end(ptr)
+
+declare arm_aapcs_vfpcc void @other2(i32 noundef, ptr noundef, ptr noundef, ptr noundef)
Index: llvm/lib/Target/ARM/ARMFrameLowering.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMFrameLowering.cpp
+++ llvm/lib/Target/ARM/ARMFrameLowering.cpp
@@ -1316,7 +1316,8 @@
                    MachineInstr::FrameDestroy);
     }
 
-    if (AFI->getGPRCalleeSavedArea2Size()) MBBI++;
+    if (AFI->getGPRCalleeSavedArea2Size() && !STI.splitFramePointerPush(MF))
+      MBBI++;
     if (AFI->getGPRCalleeSavedArea1Size()) MBBI++;
 
     if (ReservedArgStack || IncomingArgStackToRestore) {


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