xref: /freebsd/contrib/llvm-project/llvm/lib/Target/PowerPC/PPCCallingConv.cpp (revision cab6a39d7b343596a5823e65c0f7b426551ec22d)
1 //===-- PPCCallingConv.h - --------------------------------------*- 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 "PPCRegisterInfo.h"
10 #include "PPCCallingConv.h"
11 #include "PPCSubtarget.h"
12 #include "PPCCCState.h"
13 using namespace llvm;
14 
15 inline bool CC_PPC_AnyReg_Error(unsigned &, MVT &, MVT &,
16                                 CCValAssign::LocInfo &, ISD::ArgFlagsTy &,
17                                 CCState &) {
18   llvm_unreachable("The AnyReg calling convention is only supported by the " \
19                    "stackmap and patchpoint intrinsics.");
20   // gracefully fallback to PPC C calling convention on Release builds.
21   return false;
22 }
23 
24 static bool CC_PPC32_SVR4_Custom_Dummy(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
25                                        CCValAssign::LocInfo &LocInfo,
26                                        ISD::ArgFlagsTy &ArgFlags,
27                                        CCState &State) {
28   return true;
29 }
30 
31 static bool CC_PPC32_SVR4_Custom_AlignArgRegs(unsigned &ValNo, MVT &ValVT,
32                                               MVT &LocVT,
33                                               CCValAssign::LocInfo &LocInfo,
34                                               ISD::ArgFlagsTy &ArgFlags,
35                                               CCState &State) {
36   static const MCPhysReg ArgRegs[] = {
37     PPC::R3, PPC::R4, PPC::R5, PPC::R6,
38     PPC::R7, PPC::R8, PPC::R9, PPC::R10,
39   };
40   const unsigned NumArgRegs = array_lengthof(ArgRegs);
41 
42   unsigned RegNum = State.getFirstUnallocated(ArgRegs);
43 
44   // Skip one register if the first unallocated register has an even register
45   // number and there are still argument registers available which have not been
46   // allocated yet. RegNum is actually an index into ArgRegs, which means we
47   // need to skip a register if RegNum is odd.
48   if (RegNum != NumArgRegs && RegNum % 2 == 1) {
49     State.AllocateReg(ArgRegs[RegNum]);
50   }
51 
52   // Always return false here, as this function only makes sure that the first
53   // unallocated register has an odd register number and does not actually
54   // allocate a register for the current argument.
55   return false;
56 }
57 
58 static bool CC_PPC32_SVR4_Custom_SkipLastArgRegsPPCF128(
59     unsigned &ValNo, MVT &ValVT, MVT &LocVT, CCValAssign::LocInfo &LocInfo,
60     ISD::ArgFlagsTy &ArgFlags, CCState &State) {
61   static const MCPhysReg ArgRegs[] = {
62     PPC::R3, PPC::R4, PPC::R5, PPC::R6,
63     PPC::R7, PPC::R8, PPC::R9, PPC::R10,
64   };
65   const unsigned NumArgRegs = array_lengthof(ArgRegs);
66 
67   unsigned RegNum = State.getFirstUnallocated(ArgRegs);
68   int RegsLeft = NumArgRegs - RegNum;
69 
70   // Skip if there is not enough registers left for long double type (4 gpr regs
71   // in soft float mode) and put long double argument on the stack.
72   if (RegNum != NumArgRegs && RegsLeft < 4) {
73     for (int i = 0; i < RegsLeft; i++) {
74       State.AllocateReg(ArgRegs[RegNum + i]);
75     }
76   }
77 
78   return false;
79 }
80 
81 static bool CC_PPC32_SVR4_Custom_AlignFPArgRegs(unsigned &ValNo, MVT &ValVT,
82                                                 MVT &LocVT,
83                                                 CCValAssign::LocInfo &LocInfo,
84                                                 ISD::ArgFlagsTy &ArgFlags,
85                                                 CCState &State) {
86   static const MCPhysReg ArgRegs[] = {
87     PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
88     PPC::F8
89   };
90 
91   const unsigned NumArgRegs = array_lengthof(ArgRegs);
92 
93   unsigned RegNum = State.getFirstUnallocated(ArgRegs);
94 
95   // If there is only one Floating-point register left we need to put both f64
96   // values of a split ppc_fp128 value on the stack.
97   if (RegNum != NumArgRegs && ArgRegs[RegNum] == PPC::F8) {
98     State.AllocateReg(ArgRegs[RegNum]);
99   }
100 
101   // Always return false here, as this function only makes sure that the two f64
102   // values a ppc_fp128 value is split into are both passed in registers or both
103   // passed on the stack and does not actually allocate a register for the
104   // current argument.
105   return false;
106 }
107 
108 // Split F64 arguments into two 32-bit consecutive registers.
109 static bool CC_PPC32_SPE_CustomSplitFP64(unsigned &ValNo, MVT &ValVT,
110                                         MVT &LocVT,
111                                         CCValAssign::LocInfo &LocInfo,
112                                         ISD::ArgFlagsTy &ArgFlags,
113                                         CCState &State) {
114   static const MCPhysReg HiRegList[] = { PPC::R3, PPC::R5, PPC::R7, PPC::R9 };
115   static const MCPhysReg LoRegList[] = { PPC::R4, PPC::R6, PPC::R8, PPC::R10 };
116 
117   // Try to get the first register.
118   unsigned Reg = State.AllocateReg(HiRegList);
119   if (!Reg)
120     return false;
121 
122   unsigned i;
123   for (i = 0; i < sizeof(HiRegList) / sizeof(HiRegList[0]); ++i)
124     if (HiRegList[i] == Reg)
125       break;
126 
127   unsigned T = State.AllocateReg(LoRegList[i]);
128   (void)T;
129   assert(T == LoRegList[i] && "Could not allocate register");
130 
131   State.addLoc(CCValAssign::getCustomReg(ValNo, ValVT, Reg, LocVT, LocInfo));
132   State.addLoc(CCValAssign::getCustomReg(ValNo, ValVT, LoRegList[i],
133                                          LocVT, LocInfo));
134   return true;
135 }
136 
137 // Same as above, but for return values, so only allocate for R3 and R4
138 static bool CC_PPC32_SPE_RetF64(unsigned &ValNo, MVT &ValVT,
139                                MVT &LocVT,
140                                CCValAssign::LocInfo &LocInfo,
141                                ISD::ArgFlagsTy &ArgFlags,
142                                CCState &State) {
143   static const MCPhysReg HiRegList[] = { PPC::R3 };
144   static const MCPhysReg LoRegList[] = { PPC::R4 };
145 
146   // Try to get the first register.
147   unsigned Reg = State.AllocateReg(HiRegList, LoRegList);
148   if (!Reg)
149     return false;
150 
151   unsigned i;
152   for (i = 0; i < sizeof(HiRegList) / sizeof(HiRegList[0]); ++i)
153     if (HiRegList[i] == Reg)
154       break;
155 
156   State.addLoc(CCValAssign::getCustomReg(ValNo, ValVT, Reg, LocVT, LocInfo));
157   State.addLoc(CCValAssign::getCustomReg(ValNo, ValVT, LoRegList[i],
158                                          LocVT, LocInfo));
159   return true;
160 }
161 
162 #include "PPCGenCallingConv.inc"
163