Commit 0d404721 authored by Reid Kleckner's avatar Reid Kleckner
Browse files

Merging r325085: 

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r325085 | rnk | 2018-02-13 16:24:29 -0800 (Tue, 13 Feb 2018) | 3 lines

[X86] Remove dead code from retpoline thunk generation

Follow-up to r325049
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llvm-svn: 325091
parent 2caa8716

llvm/lib/Target/X86/X86RetpolineThunks.cpp

+0 −26
Original line number Diff line number Diff line
@@ -74,7 +74,6 @@ private: 


  void createThunkFunction(Module &M, StringRef Name);

  void insertRegReturnAddrClobber(MachineBasicBlock &MBB, unsigned Reg);

  void insert32BitPushReturnAddrClobber(MachineBasicBlock &MBB);

  void populateThunk(MachineFunction &MF, Optional<unsigned> Reg = None);

};
@@ -225,31 +224,6 @@ void X86RetpolineThunks::insertRegReturnAddrClobber(MachineBasicBlock &MBB, 
      .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...