}
}
- bool IsV4PopReturn = false;
- for (const CalleeSavedInfo &CSI : MFI->getCalleeSavedInfo())
- if (CSI.getReg() == ARM::LR)
- IsV4PopReturn = true;
- IsV4PopReturn &= STI.hasV4TOps() && !STI.hasV5TOps();
-
- // Unlike T2 and ARM mode, the T1 pop instruction cannot restore
- // to LR, and we can't pop the value directly to the PC since
- // we need to update the SP after popping the value. So instead
- // we have to emit:
- // POP {r3}
- // ADD sp, #offset
- // BX r3
- // If this would clobber a return value, then generate this sequence instead:
- // MOV ip, r3
- // POP {r3}
- // ADD sp, #offset
- // MOV lr, r3
- // MOV r3, ip
- // BX lr
- if (ArgRegsSaveSize || IsV4PopReturn) {
+ if (ArgRegsSaveSize) {
+ // Unlike T2 and ARM mode, the T1 pop instruction cannot restore
+ // to LR, and we can't pop the value directly to the PC since
+ // we need to update the SP after popping the value. Therefore, we
+ // pop the old LR into R3 as a temporary.
+
// Get the last instruction, tBX_RET
MBBI = MBB.getLastNonDebugInstr();
assert (MBBI->getOpcode() == ARM::tBX_RET);
- DebugLoc dl = MBBI->getDebugLoc();
-
- if (AFI->getReturnRegsCount() <= 3) {
- // Epilogue: pop saved LR to R3 and branch off it.
- AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
- .addReg(ARM::R3, RegState::Define);
-
- emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, ArgRegsSaveSize);
-
- MachineInstrBuilder MIB =
- BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX))
- .addReg(ARM::R3, RegState::Kill);
- AddDefaultPred(MIB);
- MIB.copyImplicitOps(&*MBBI);
- // erase the old tBX_RET instruction
- MBB.erase(MBBI);
- } else {
- AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
- .addReg(ARM::R12, RegState::Define)
- .addReg(ARM::R3, RegState::Kill));
-
- AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
- .addReg(ARM::R3, RegState::Define);
-
- emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, ArgRegsSaveSize);
-
- AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
- .addReg(ARM::LR, RegState::Define)
- .addReg(ARM::R3, RegState::Kill));
-
- AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr))
- .addReg(ARM::R3, RegState::Define)
- .addReg(ARM::R12, RegState::Kill));
- // Keep the tBX_RET instruction
- }
+ // Epilogue for vararg functions: pop LR to R3 and branch off it.
+ AddDefaultPred(BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)))
+ .addReg(ARM::R3, RegState::Define);
+
+ emitSPUpdate(MBB, MBBI, TII, dl, *RegInfo, ArgRegsSaveSize);
+
+ MachineInstrBuilder MIB =
+ BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg))
+ .addReg(ARM::R3, RegState::Kill);
+ AddDefaultPred(MIB);
+ MIB.copyImplicitOps(&*MBBI);
+ // erase the old tBX_RET instruction
+ MBB.erase(MBBI);
}
}
// Special epilogue for vararg functions. See emitEpilogue
if (isVarArg)
continue;
- // ARMv4T requires BX, see emitEpilogue
- if (STI.hasV4TOps() && !STI.hasV5TOps())
- continue;
Reg = ARM::PC;
(*MIB).setDesc(TII.get(ARM::tPOP_RET));
MIB.copyImplicitOps(&*MI);