1 //===- TargetRegisterInfo.cpp - Target Register Information Implementation ===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the TargetRegisterInfo interface.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Target/TargetMachine.h"
15 #include "llvm/Target/TargetRegisterInfo.h"
16 #include "llvm/Target/TargetFrameInfo.h"
17 #include "llvm/CodeGen/MachineFunction.h"
18 #include "llvm/CodeGen/MachineFrameInfo.h"
19 #include "llvm/ADT/BitVector.h"
23 TargetRegisterInfo::TargetRegisterInfo(const TargetRegisterDesc *D, unsigned NR,
24 regclass_iterator RCB, regclass_iterator RCE,
25 const char *const *subregindexnames,
27 const unsigned* subregs, const unsigned subregsize,
28 const unsigned* superregs, const unsigned superregsize,
29 const unsigned* aliases, const unsigned aliasessize)
30 : SubregHash(subregs), SubregHashSize(subregsize),
31 SuperregHash(superregs), SuperregHashSize(superregsize),
32 AliasesHash(aliases), AliasesHashSize(aliasessize),
33 Desc(D), SubRegIndexNames(subregindexnames), NumRegs(NR),
34 RegClassBegin(RCB), RegClassEnd(RCE) {
35 assert(NumRegs < FirstVirtualRegister &&
36 "Target has too many physical registers!");
38 CallFrameSetupOpcode = CFSO;
39 CallFrameDestroyOpcode = CFDO;
42 TargetRegisterInfo::~TargetRegisterInfo() {}
44 /// getPhysicalRegisterRegClass - Returns the Register Class of a physical
45 /// register of the given type. If type is EVT::Other, then just return any
46 /// register class the register belongs to.
47 const TargetRegisterClass *
48 TargetRegisterInfo::getPhysicalRegisterRegClass(unsigned reg, EVT VT) const {
49 assert(isPhysicalRegister(reg) && "reg must be a physical register");
51 // Pick the most super register class of the right type that contains
53 const TargetRegisterClass* BestRC = 0;
54 for (regclass_iterator I = regclass_begin(), E = regclass_end(); I != E; ++I){
55 const TargetRegisterClass* RC = *I;
56 if ((VT == MVT::Other || RC->hasType(VT)) && RC->contains(reg) &&
57 (!BestRC || BestRC->hasSuperClass(RC)))
61 assert(BestRC && "Couldn't find the register class");
65 /// getAllocatableSetForRC - Toggle the bits that represent allocatable
66 /// registers for the specific register class.
67 static void getAllocatableSetForRC(const MachineFunction &MF,
68 const TargetRegisterClass *RC, BitVector &R){
69 for (TargetRegisterClass::iterator I = RC->allocation_order_begin(MF),
70 E = RC->allocation_order_end(MF); I != E; ++I)
74 BitVector TargetRegisterInfo::getAllocatableSet(const MachineFunction &MF,
75 const TargetRegisterClass *RC) const {
76 BitVector Allocatable(NumRegs);
78 getAllocatableSetForRC(MF, RC, Allocatable);
82 for (TargetRegisterInfo::regclass_iterator I = regclass_begin(),
83 E = regclass_end(); I != E; ++I)
84 getAllocatableSetForRC(MF, *I, Allocatable);
88 /// getFrameIndexOffset - Returns the displacement from the frame register to
89 /// the stack frame of the specified index. This is the default implementation
90 /// which is overridden for some targets.
91 int TargetRegisterInfo::getFrameIndexOffset(const MachineFunction &MF,
93 const TargetFrameInfo &TFI = *MF.getTarget().getFrameInfo();
94 const MachineFrameInfo *MFI = MF.getFrameInfo();
95 return MFI->getObjectOffset(FI) + MFI->getStackSize() -
96 TFI.getOffsetOfLocalArea() + MFI->getOffsetAdjustment();
99 /// getInitialFrameState - Returns a list of machine moves that are assumed
100 /// on entry to a function.
102 TargetRegisterInfo::getInitialFrameState(std::vector<MachineMove> &Moves) const{
103 // Default is to do nothing.
106 const TargetRegisterClass *
107 llvm::getCommonSubClass(const TargetRegisterClass *A,
108 const TargetRegisterClass *B) {
109 // First take care of the trivial cases
115 // If B is a subclass of A, it will be handled in the loop below
116 if (B->hasSubClass(A))
119 const TargetRegisterClass *Best = 0;
120 for (TargetRegisterClass::sc_iterator I = A->subclasses_begin();
121 const TargetRegisterClass *X = *I; ++I) {
123 return B; // B is a subclass of A
125 // X must be a common subclass of A and B
126 if (!B->hasSubClass(X))
129 // A superclass is definitely better.
130 if (!Best || Best->hasSuperClass(X)) {
135 // A subclass is definitely worse
136 if (Best->hasSubClass(X))
139 // Best and *I have no super/sub class relation - pick the larger class, or
140 // the smaller spill size.
141 int nb = std::distance(Best->begin(), Best->end());
142 int ni = std::distance(X->begin(), X->end());
143 if (ni>nb || (ni==nb && X->getSize() < Best->getSize()))