1 //===- SystemZInstrBuilder.h - Functions to aid building  insts -*- 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 exposes functions that may be used with BuildMI from the
11 // MachineInstrBuilder.h file to handle SystemZ'isms in a clean way.
12 //
13 // The BuildMem function may be used with the BuildMI function to add entire
14 // memory references in a single, typed, function call.
15 //
16 // For reference, the order of operands for memory references is:
17 // (Operand), Base, Displacement, Index.
18 //
19 //===----------------------------------------------------------------------===//
20 
21 #ifndef SYSTEMZINSTRBUILDER_H
22 #define SYSTEMZINSTRBUILDER_H
23 
24 #include "llvm/CodeGen/MachineFrameInfo.h"
25 #include "llvm/CodeGen/MachineInstrBuilder.h"
26 #include "llvm/CodeGen/PseudoSourceValue.h"
27 
28 namespace llvm {
29 
30 /// SystemZAddressMode - This struct holds a generalized full x86 address mode.
31 /// The base register can be a frame index, which will eventually be replaced
32 /// with R15 or R11 and Disp being offsetted accordingly.
33 struct SystemZAddressMode {
34   enum {
35     RegBase,
36     FrameIndexBase
37   } BaseType;
38 
39   union {
40     unsigned Reg;
41     int FrameIndex;
42   } Base;
43 
44   unsigned IndexReg;
45   int32_t Disp;
46   GlobalValue *GV;
47 
48   SystemZAddressMode() : BaseType(RegBase), IndexReg(0), Disp(0) {
49     Base.Reg = 0;
50   }
51 };
52 
53 /// addDirectMem - This function is used to add a direct memory reference to the
54 /// current instruction -- that is, a dereference of an address in a register,
55 /// with no index or displacement.
56 ///
57 static inline const MachineInstrBuilder &
58 addDirectMem(const MachineInstrBuilder &MIB, unsigned Reg) {
59   // Because memory references are always represented with 3
60   // values, this adds: Reg, [0, NoReg] to the instruction.
61   return MIB.addReg(Reg).addImm(0).addReg(0);
62 }
63 
64 static inline const MachineInstrBuilder &
65 addOffset(const MachineInstrBuilder &MIB, int Offset) {
66   return MIB.addImm(Offset).addReg(0);
67 }
68 
69 /// addRegOffset - This function is used to add a memory reference of the form
70 /// [Reg + Offset], i.e., one with no or index, but with a
71 /// displacement. An example is: 10(%r15).
72 ///
73 static inline const MachineInstrBuilder &
74 addRegOffset(const MachineInstrBuilder &MIB,
75              unsigned Reg, bool isKill, int Offset) {
76   return addOffset(MIB.addReg(Reg, getKillRegState(isKill)), Offset);
77 }
78 
79 /// addRegReg - This function is used to add a memory reference of the form:
80 /// [Reg + Reg].
81 static inline const MachineInstrBuilder &
82 addRegReg(const MachineInstrBuilder &MIB,
83             unsigned Reg1, bool isKill1, unsigned Reg2, bool isKill2) {
84   return MIB.addReg(Reg1, getKillRegState(isKill1)).addImm(0)
85     .addReg(Reg2, getKillRegState(isKill2));
86 }
87 
88 static inline const MachineInstrBuilder &
89 addFullAddress(const MachineInstrBuilder &MIB, const SystemZAddressMode &AM) {
90   if (AM.BaseType == SystemZAddressMode::RegBase)
91     MIB.addReg(AM.Base.Reg);
92   else if (AM.BaseType == SystemZAddressMode::FrameIndexBase)
93     MIB.addFrameIndex(AM.Base.FrameIndex);
94   else
95     assert(0);
96 
97   return MIB.addImm(AM.Disp).addReg(AM.IndexReg);
98 }
99 
100 /// addFrameReference - This function is used to add a reference to the base of
101 /// an abstract object on the stack frame of the current function.  This
102 /// reference has base register as the FrameIndex offset until it is resolved.
103 /// This allows a constant offset to be specified as well...
104 ///
105 static inline const MachineInstrBuilder &
106 addFrameReference(const MachineInstrBuilder &MIB, int FI, int Offset = 0) {
107   MachineInstr *MI = MIB;
108   MachineFunction &MF = *MI->getParent()->getParent();
109   MachineFrameInfo &MFI = *MF.getFrameInfo();
110   const TargetInstrDesc &TID = MI->getDesc();
111   unsigned Flags = 0;
112   if (TID.mayLoad())
113     Flags |= MachineMemOperand::MOLoad;
114   if (TID.mayStore())
115     Flags |= MachineMemOperand::MOStore;
116   MachineMemOperand MMO(PseudoSourceValue::getFixedStack(FI),
117                         Flags,
118                         MFI.getObjectOffset(FI) + Offset,
119                         MFI.getObjectSize(FI),
120                         MFI.getObjectAlignment(FI));
121   return addOffset(MIB.addFrameIndex(FI), Offset)
122             .addMemOperand(MMO);
123 }
124 
125 } // End llvm namespace
126 
127 #endif
128