From 3904343c68926f1ed8250e4a9b0863868f1ffb74 Mon Sep 17 00:00:00 2001 From: Eric Christopher Date: Tue, 11 Jan 2011 00:16:04 +0000 Subject: Even if we don't have 7 bytes of stack space we may need to save and restore the stack pointer from the frame pointer on thumbv6. Fixes rdar://8819685 llvm-svn: 123196 --- llvm/lib/Target/ARM/Thumb1FrameLowering.cpp | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'llvm/lib/Target/ARM/Thumb1FrameLowering.cpp') diff --git a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp index e3f2d2d5981..8a6dda82148 100644 --- a/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp +++ b/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp @@ -156,6 +156,12 @@ void Thumb1FrameLowering::emitPrologue(MachineFunction &MF) const { // to reference locals. if (RegInfo->hasBasePointer(MF)) BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVgpr2gpr), BasePtr).addReg(ARM::SP); + + // If the frame has variable sized objects then the epilogue must restore + // the sp from fp. We can assume there's an FP here since hasFP already + // checks for hasVarSizedObjects. + if (MFI->hasVarSizedObjects()) + AFI->setShouldRestoreSPFromFP(true); } static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) { @@ -221,7 +227,8 @@ void Thumb1FrameLowering::emitEpilogue(MachineFunction &MF, if (AFI->shouldRestoreSPFromFP()) { NumBytes = AFI->getFramePtrSpillOffset() - NumBytes; // Reset SP based on frame pointer only if the stack frame extends beyond - // frame pointer stack slot or target is ELF and the function has FP. + // frame pointer stack slot, the target is ELF and the function has FP, or + // the target uses var sized objects. if (NumBytes) { assert(MF.getRegInfo().isPhysRegUsed(ARM::R4) && "No scratch register to restore SP from FP!"); -- cgit v1.2.3