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1 //=== AArch64CallingConv.h - Custom Calling Convention Routines -*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains the custom routines for the AArch64 Calling Convention
11 // that aren't done by tablegen.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_LIB_TARGET_AARCH64_AARCH64CALLINGCONVENTION_H
16 #define LLVM_LIB_TARGET_AARCH64_AARCH64CALLINGCONVENTION_H
17 
18 #include "AArch64.h"
19 #include "AArch64InstrInfo.h"
20 #include "AArch64Subtarget.h"
21 #include "llvm/CodeGen/CallingConvLower.h"
22 #include "llvm/IR/CallingConv.h"
23 #include "llvm/Target/TargetInstrInfo.h"
24 
25 namespace {
26 using namespace llvm;
27 
28 static const MCPhysReg XRegList[] = {AArch64::X0, AArch64::X1, AArch64::X2,
29                                      AArch64::X3, AArch64::X4, AArch64::X5,
30                                      AArch64::X6, AArch64::X7};
31 static const MCPhysReg HRegList[] = {AArch64::H0, AArch64::H1, AArch64::H2,
32                                      AArch64::H3, AArch64::H4, AArch64::H5,
33                                      AArch64::H6, AArch64::H7};
34 static const MCPhysReg SRegList[] = {AArch64::S0, AArch64::S1, AArch64::S2,
35                                      AArch64::S3, AArch64::S4, AArch64::S5,
36                                      AArch64::S6, AArch64::S7};
37 static const MCPhysReg DRegList[] = {AArch64::D0, AArch64::D1, AArch64::D2,
38                                      AArch64::D3, AArch64::D4, AArch64::D5,
39                                      AArch64::D6, AArch64::D7};
40 static const MCPhysReg QRegList[] = {AArch64::Q0, AArch64::Q1, AArch64::Q2,
41                                      AArch64::Q3, AArch64::Q4, AArch64::Q5,
42                                      AArch64::Q6, AArch64::Q7};
43 
finishStackBlock(SmallVectorImpl<CCValAssign> & PendingMembers,MVT LocVT,ISD::ArgFlagsTy & ArgFlags,CCState & State,unsigned SlotAlign)44 static bool finishStackBlock(SmallVectorImpl<CCValAssign> &PendingMembers,
45                              MVT LocVT, ISD::ArgFlagsTy &ArgFlags,
46                              CCState &State, unsigned SlotAlign) {
47   unsigned Size = LocVT.getSizeInBits() / 8;
48   unsigned StackAlign =
49       State.getMachineFunction().getDataLayout().getStackAlignment();
50   unsigned Align = std::min(ArgFlags.getOrigAlign(), StackAlign);
51 
52   for (auto &It : PendingMembers) {
53     It.convertToMem(State.AllocateStack(Size, std::max(Align, SlotAlign)));
54     State.addLoc(It);
55     SlotAlign = 1;
56   }
57 
58   // All pending members have now been allocated
59   PendingMembers.clear();
60   return true;
61 }
62 
63 /// The Darwin variadic PCS places anonymous arguments in 8-byte stack slots. An
64 /// [N x Ty] type must still be contiguous in memory though.
CC_AArch64_Custom_Stack_Block(unsigned & ValNo,MVT & ValVT,MVT & LocVT,CCValAssign::LocInfo & LocInfo,ISD::ArgFlagsTy & ArgFlags,CCState & State)65 static bool CC_AArch64_Custom_Stack_Block(
66       unsigned &ValNo, MVT &ValVT, MVT &LocVT, CCValAssign::LocInfo &LocInfo,
67       ISD::ArgFlagsTy &ArgFlags, CCState &State) {
68   SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
69 
70   // Add the argument to the list to be allocated once we know the size of the
71   // block.
72   PendingMembers.push_back(
73       CCValAssign::getPending(ValNo, ValVT, LocVT, LocInfo));
74 
75   if (!ArgFlags.isInConsecutiveRegsLast())
76     return true;
77 
78   return finishStackBlock(PendingMembers, LocVT, ArgFlags, State, 8);
79 }
80 
81 /// Given an [N x Ty] block, it should be passed in a consecutive sequence of
82 /// registers. If no such sequence is available, mark the rest of the registers
83 /// of that type as used and place the argument on the stack.
CC_AArch64_Custom_Block(unsigned & ValNo,MVT & ValVT,MVT & LocVT,CCValAssign::LocInfo & LocInfo,ISD::ArgFlagsTy & ArgFlags,CCState & State)84 static bool CC_AArch64_Custom_Block(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
85                                     CCValAssign::LocInfo &LocInfo,
86                                     ISD::ArgFlagsTy &ArgFlags, CCState &State) {
87   // Try to allocate a contiguous block of registers, each of the correct
88   // size to hold one member.
89   ArrayRef<MCPhysReg> RegList;
90   if (LocVT.SimpleTy == MVT::i64)
91     RegList = XRegList;
92   else if (LocVT.SimpleTy == MVT::f16)
93     RegList = HRegList;
94   else if (LocVT.SimpleTy == MVT::f32 || LocVT.is32BitVector())
95     RegList = SRegList;
96   else if (LocVT.SimpleTy == MVT::f64 || LocVT.is64BitVector())
97     RegList = DRegList;
98   else if (LocVT.SimpleTy == MVT::f128 || LocVT.is128BitVector())
99     RegList = QRegList;
100   else {
101     // Not an array we want to split up after all.
102     return false;
103   }
104 
105   SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
106 
107   // Add the argument to the list to be allocated once we know the size of the
108   // block.
109   PendingMembers.push_back(
110       CCValAssign::getPending(ValNo, ValVT, LocVT, LocInfo));
111 
112   if (!ArgFlags.isInConsecutiveRegsLast())
113     return true;
114 
115   unsigned RegResult = State.AllocateRegBlock(RegList, PendingMembers.size());
116   if (RegResult) {
117     for (auto &It : PendingMembers) {
118       It.convertToReg(RegResult);
119       State.addLoc(It);
120       ++RegResult;
121     }
122     PendingMembers.clear();
123     return true;
124   }
125 
126   // Mark all regs in the class as unavailable
127   for (auto Reg : RegList)
128     State.AllocateReg(Reg);
129 
130   const AArch64Subtarget &Subtarget = static_cast<const AArch64Subtarget &>(
131       State.getMachineFunction().getSubtarget());
132   unsigned SlotAlign = Subtarget.isTargetDarwin() ? 1 : 8;
133 
134   return finishStackBlock(PendingMembers, LocVT, ArgFlags, State, SlotAlign);
135 }
136 
137 }
138 
139 #endif
140