1 //===-- ARMWinEH.cpp - Windows on ARM EH Support Functions ------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/Support/ARMWinEH.h"
10 
11 namespace llvm {
12 namespace ARM {
13 namespace WinEH {
14 std::pair<uint16_t, uint32_t> SavedRegisterMask(const RuntimeFunction &RF,
15                                                 bool Prologue) {
16   uint8_t NumRegisters = RF.Reg();
17   uint8_t RegistersVFP = RF.R();
18   uint8_t LinkRegister = RF.L();
19   uint8_t ChainedFrame = RF.C();
20 
21   uint16_t GPRMask = (ChainedFrame << 11);
22   uint32_t VFPMask = 0;
23 
24   if (Prologue) {
25     GPRMask |= (LinkRegister << 14);
26   } else {
27     // If Ret != 0, we pop into Lr and return later
28     if (RF.Ret() != ReturnType::RT_POP)
29       GPRMask |= (LinkRegister << 14);
30     else if (!RF.H()) // If H == 0, we pop directly into Pc
31       GPRMask |= (LinkRegister << 15);
32     // else, Ret == 0 && H == 1, we pop into Pc separately afterwards
33   }
34 
35   if (RegistersVFP)
36     VFPMask |= (((1 << ((NumRegisters + 1) % 8)) - 1) << 8);
37   else
38     GPRMask |= (((1 << (NumRegisters + 1)) - 1) << 4);
39 
40   if ((PrologueFolding(RF) && Prologue) || (EpilogueFolding(RF) && !Prologue))
41     GPRMask |= (((1 << ((RF.StackAdjust() & 0x3) + 1)) - 1)
42                 << (~RF.StackAdjust() & 0x3));
43 
44   return std::make_pair(GPRMask, VFPMask);
45 }
46 } // namespace WinEH
47 } // namespace ARM
48 } // namespace llvm
49 
50