[ARM] Fix unwind info for Thumb1 functions that save high registers.

There were two issues here: one, some of the relevant instructions were
missing the expected "FrameSetup" flag, and two,
ARMAsmPrinter::EmitUnwindingInstruction wasn't expecting "mov"
instructions in the prologue.

I'm sticking the additional state into ARMFunctionInfo so it's obvious
it only applies to the current function.

I considered a few alternative approaches where we would compute the
correct unwind information as part of the prologue/epilogue lowering,
but it seems like a lot of work to introduce pseudo-instructions, and
the current code seems to be reliable enough.

Fixes https://bugs.llvm.org/show_bug.cgi?id=42408.

Differential Revision: https://reviews.llvm.org/D63964

llvm-svn: 364970

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
index 1b32df2104a..426e9a0ed9b 100644
--- a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
+++ b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp
@@ -889,8 +889,9 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
         findNextOrderedReg(std::begin(AllCopyRegs), CopyRegs, AllCopyRegsEnd);
 
     // Create the PUSH, but don't insert it yet (the MOVs need to come first).
-    MachineInstrBuilder PushMIB =
-        BuildMI(MF, DL, TII.get(ARM::tPUSH)).add(predOps(ARMCC::AL));
+    MachineInstrBuilder PushMIB = BuildMI(MF, DL, TII.get(ARM::tPUSH))
+                                      .add(predOps(ARMCC::AL))
+                                      .setMIFlags(MachineInstr::FrameSetup);
 
     SmallVector<unsigned, 4> RegsToPush;
     while (HiRegToSave != AllHighRegsEnd && CopyReg != AllCopyRegsEnd) {
@@ -903,7 +904,8 @@ spillCalleeSavedRegisters(MachineBasicBlock &MBB,
         BuildMI(MBB, MI, DL, TII.get(ARM::tMOVr))
             .addReg(*CopyReg, RegState::Define)
             .addReg(*HiRegToSave, getKillRegState(isKill))
-            .add(predOps(ARMCC::AL));
+            .add(predOps(ARMCC::AL))
+            .setMIFlags(MachineInstr::FrameSetup);
 
         // Record the register that must be added to the PUSH.
         RegsToPush.push_back(*CopyReg);