1 //===-- SystemZCallingConv.h - Calling conventions for SystemZ --*- 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 #ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZCALLINGCONV_H
10 #define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZCALLINGCONV_H
11 
12 #include "llvm/ADT/SmallVector.h"
13 #include "llvm/CodeGen/CallingConvLower.h"
14 #include "llvm/MC/MCRegisterInfo.h"
15 
16 namespace llvm {
17 namespace SystemZ {
18   const unsigned NumArgGPRs = 5;
19   extern const MCPhysReg ArgGPRs[NumArgGPRs];
20 
21   const unsigned NumArgFPRs = 4;
22   extern const MCPhysReg ArgFPRs[NumArgFPRs];
23 } // end namespace SystemZ
24 
25 class SystemZCCState : public CCState {
26 private:
27   /// Records whether the value was a fixed argument.
28   /// See ISD::OutputArg::IsFixed.
29   SmallVector<bool, 4> ArgIsFixed;
30 
31   /// Records whether the value was widened from a short vector type.
32   SmallVector<bool, 4> ArgIsShortVector;
33 
34   // Check whether ArgVT is a short vector type.
35   bool IsShortVectorType(EVT ArgVT) {
36     return ArgVT.isVector() && ArgVT.getStoreSize() <= 8;
37   }
38 
39 public:
40   SystemZCCState(CallingConv::ID CC, bool isVarArg, MachineFunction &MF,
41                  SmallVectorImpl<CCValAssign> &locs, LLVMContext &C)
42       : CCState(CC, isVarArg, MF, locs, C) {}
43 
44   void AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
45                               CCAssignFn Fn) {
46     // Formal arguments are always fixed.
47     ArgIsFixed.clear();
48     for (unsigned i = 0; i < Ins.size(); ++i)
49       ArgIsFixed.push_back(true);
50     // Record whether the call operand was a short vector.
51     ArgIsShortVector.clear();
52     for (unsigned i = 0; i < Ins.size(); ++i)
53       ArgIsShortVector.push_back(IsShortVectorType(Ins[i].ArgVT));
54 
55     CCState::AnalyzeFormalArguments(Ins, Fn);
56   }
57 
58   void AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
59                            CCAssignFn Fn) {
60     // Record whether the call operand was a fixed argument.
61     ArgIsFixed.clear();
62     for (unsigned i = 0; i < Outs.size(); ++i)
63       ArgIsFixed.push_back(Outs[i].IsFixed);
64     // Record whether the call operand was a short vector.
65     ArgIsShortVector.clear();
66     for (unsigned i = 0; i < Outs.size(); ++i)
67       ArgIsShortVector.push_back(IsShortVectorType(Outs[i].ArgVT));
68 
69     CCState::AnalyzeCallOperands(Outs, Fn);
70   }
71 
72   // This version of AnalyzeCallOperands in the base class is not usable
73   // since we must provide a means of accessing ISD::OutputArg::IsFixed.
74   void AnalyzeCallOperands(const SmallVectorImpl<MVT> &Outs,
75                            SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
76                            CCAssignFn Fn) = delete;
77 
78   bool IsFixed(unsigned ValNo) { return ArgIsFixed[ValNo]; }
79   bool IsShortVector(unsigned ValNo) { return ArgIsShortVector[ValNo]; }
80 };
81 
82 // Handle i128 argument types.  These need to be passed by implicit
83 // reference.  This could be as simple as the following .td line:
84 //    CCIfType<[i128], CCPassIndirect<i64>>,
85 // except that i128 is not a legal type, and therefore gets split by
86 // common code into a pair of i64 arguments.
87 inline bool CC_SystemZ_I128Indirect(unsigned &ValNo, MVT &ValVT,
88                                     MVT &LocVT,
89                                     CCValAssign::LocInfo &LocInfo,
90                                     ISD::ArgFlagsTy &ArgFlags,
91                                     CCState &State) {
92   SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
93 
94   // ArgFlags.isSplit() is true on the first part of a i128 argument;
95   // PendingMembers.empty() is false on all subsequent parts.
96   if (!ArgFlags.isSplit() && PendingMembers.empty())
97     return false;
98 
99   // Push a pending Indirect value location for each part.
100   LocVT = MVT::i64;
101   LocInfo = CCValAssign::Indirect;
102   PendingMembers.push_back(CCValAssign::getPending(ValNo, ValVT,
103                                                    LocVT, LocInfo));
104   if (!ArgFlags.isSplitEnd())
105     return true;
106 
107   // OK, we've collected all parts in the pending list.  Allocate
108   // the location (register or stack slot) for the indirect pointer.
109   // (This duplicates the usual i64 calling convention rules.)
110   unsigned Reg = State.AllocateReg(SystemZ::ArgGPRs);
111   unsigned Offset = Reg ? 0 : State.AllocateStack(8, Align(8));
112 
113   // Use that same location for all the pending parts.
114   for (auto &It : PendingMembers) {
115     if (Reg)
116       It.convertToReg(Reg);
117     else
118       It.convertToMem(Offset);
119     State.addLoc(It);
120   }
121 
122   PendingMembers.clear();
123 
124   return true;
125 }
126 
127 inline bool CC_SystemZ_GHC_Error(unsigned &, MVT &, MVT &,
128                                  CCValAssign::LocInfo &, ISD::ArgFlagsTy &,
129                                  CCState &) {
130   report_fatal_error("No registers left in GHC calling convention");
131   return false;
132 }
133 
134 } // end namespace llvm
135 
136 #endif
137