1 //===- AArch64CallLowering.h - Call lowering --------------------*- 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 /// \file
10 /// This file describes how to lower LLVM calls to machine code calls.
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_TARGET_AARCH64_AARCH64CALLLOWERING_H
15 #define LLVM_LIB_TARGET_AARCH64_AARCH64CALLLOWERING_H
16 
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/CodeGen/GlobalISel/CallLowering.h"
19 #include "llvm/IR/CallingConv.h"
20 #include <cstdint>
21 #include <functional>
22 
23 namespace llvm {
24 
25 class AArch64TargetLowering;
26 class CCValAssign;
27 class MachineIRBuilder;
28 class Type;
29 
30 class AArch64CallLowering: public CallLowering {
31 public:
32   AArch64CallLowering(const AArch64TargetLowering &TLI);
33 
34   bool lowerReturn(MachineIRBuilder &MIRBuilder, const Value *Val,
35                    ArrayRef<Register> VRegs, FunctionLoweringInfo &FLI,
36                    Register SwiftErrorVReg) const override;
37 
38   bool canLowerReturn(MachineFunction &MF, CallingConv::ID CallConv,
39                       SmallVectorImpl<BaseArgInfo> &Outs,
40                       bool IsVarArg) const override;
41 
42   bool fallBackToDAGISel(const MachineFunction &MF) const override;
43 
44   bool lowerFormalArguments(MachineIRBuilder &MIRBuilder, const Function &F,
45                             ArrayRef<ArrayRef<Register>> VRegs,
46                             FunctionLoweringInfo &FLI) const override;
47 
48   bool lowerCall(MachineIRBuilder &MIRBuilder,
49                  CallLoweringInfo &Info) const override;
50 
51   /// Returns true if the call can be lowered as a tail call.
52   bool
53   isEligibleForTailCallOptimization(MachineIRBuilder &MIRBuilder,
54                                     CallLoweringInfo &Info,
55                                     SmallVectorImpl<ArgInfo> &InArgs,
56                                     SmallVectorImpl<ArgInfo> &OutArgs) const;
57 
58   bool supportSwiftError() const override { return true; }
59 
60   bool isTypeIsValidForThisReturn(EVT Ty) const override;
61 
62 private:
63   using RegHandler = std::function<void(MachineIRBuilder &, Type *, unsigned,
64                                         CCValAssign &)>;
65 
66   using MemHandler =
67       std::function<void(MachineIRBuilder &, int, CCValAssign &)>;
68 
69   void saveVarArgRegisters(MachineIRBuilder &MIRBuilder,
70                            CallLowering::IncomingValueHandler &Handler,
71                            CCState &CCInfo) const;
72 
73   bool lowerTailCall(MachineIRBuilder &MIRBuilder, CallLoweringInfo &Info,
74                      SmallVectorImpl<ArgInfo> &OutArgs) const;
75 
76   bool
77   doCallerAndCalleePassArgsTheSameWay(CallLoweringInfo &Info,
78                                       MachineFunction &MF,
79                                       SmallVectorImpl<ArgInfo> &InArgs) const;
80 
81   bool
82   areCalleeOutgoingArgsTailCallable(CallLoweringInfo &Info, MachineFunction &MF,
83                                     SmallVectorImpl<ArgInfo> &OutArgs) const;
84 };
85 
86 } // end namespace llvm
87 
88 #endif // LLVM_LIB_TARGET_AARCH64_AARCH64CALLLOWERING_H
89