void createThunkFunction(Module &M, StringRef Name);
void insertRegReturnAddrClobber(MachineBasicBlock &MBB, unsigned Reg);
- void insert32BitPushReturnAddrClobber(MachineBasicBlock &MBB);
void populateThunk(MachineFunction &MF, Optional<unsigned> Reg = None);
};
.addReg(Reg);
}
-void X86RetpolineThunks::insert32BitPushReturnAddrClobber(
- MachineBasicBlock &MBB) {
- // The instruction sequence we use to replace the return address without
- // a scratch register is somewhat complicated:
- // # Clear capture_spec from return address.
- // addl $4, %esp
- // # Top of stack words are: Callee, RA. Exchange Callee and RA.
- // pushl 4(%esp) # Push callee
- // pushl 4(%esp) # Push RA
- // popl 8(%esp) # Pop RA to final RA
- // popl (%esp) # Pop callee to next top of stack
- // retl # Ret to callee
- BuildMI(&MBB, DebugLoc(), TII->get(X86::ADD32ri), X86::ESP)
- .addReg(X86::ESP)
- .addImm(4);
- addRegOffset(BuildMI(&MBB, DebugLoc(), TII->get(X86::PUSH32rmm)), X86::ESP,
- false, 4);
- addRegOffset(BuildMI(&MBB, DebugLoc(), TII->get(X86::PUSH32rmm)), X86::ESP,
- false, 4);
- addRegOffset(BuildMI(&MBB, DebugLoc(), TII->get(X86::POP32rmm)), X86::ESP,
- false, 8);
- addRegOffset(BuildMI(&MBB, DebugLoc(), TII->get(X86::POP32rmm)), X86::ESP,
- false, 0);
-}
-
void X86RetpolineThunks::populateThunk(MachineFunction &MF,
Optional<unsigned> Reg) {
// Set MF properties. We never use vregs...