CodeGenRegisters.cpp revision b5923db192d2aa938ff3c12aaac87d80ab649625 
1//===- CodeGenRegisters.cpp - Register and RegisterClass Info -------------===//
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 defines structures to encapsulate information gleaned from the
11// target register and register class definitions.
12//
13//===----------------------------------------------------------------------===//
14
15#include "CodeGenRegisters.h"
16#include "CodeGenTarget.h"
17#include "llvm/ADT/SmallVector.h"
18#include "llvm/ADT/StringExtras.h"
19
20using namespace llvm;
21
22//===----------------------------------------------------------------------===//
23//                              CodeGenRegister
24//===----------------------------------------------------------------------===//
25
26CodeGenRegister::CodeGenRegister(Record *R, unsigned Enum)
27  : TheDef(R),
28    EnumValue(Enum),
29    CostPerUse(R->getValueAsInt("CostPerUse")),
30    SubRegsComplete(false)
31{}
32
33const std::string &CodeGenRegister::getName() const {
34  return TheDef->getName();
35}
36
37namespace {
38  struct Orphan {
39    CodeGenRegister *SubReg;
40    Record *First, *Second;
41    Orphan(CodeGenRegister *r, Record *a, Record *b)
42      : SubReg(r), First(a), Second(b) {}
43  };
44}
45
46const CodeGenRegister::SubRegMap &
47CodeGenRegister::getSubRegs(CodeGenRegBank &RegBank) {
48  // Only compute this map once.
49  if (SubRegsComplete)
50    return SubRegs;
51  SubRegsComplete = true;
52
53  std::vector<Record*> SubList = TheDef->getValueAsListOfDefs("SubRegs");
54  std::vector<Record*> Indices = TheDef->getValueAsListOfDefs("SubRegIndices");
55  if (SubList.size() != Indices.size())
56    throw TGError(TheDef->getLoc(), "Register " + getName() +
57                  " SubRegIndices doesn't match SubRegs");
58
59  // First insert the direct subregs and make sure they are fully indexed.
60  for (unsigned i = 0, e = SubList.size(); i != e; ++i) {
61    CodeGenRegister *SR = RegBank.getReg(SubList[i]);
62    if (!SubRegs.insert(std::make_pair(Indices[i], SR)).second)
63      throw TGError(TheDef->getLoc(), "SubRegIndex " + Indices[i]->getName() +
64                    " appears twice in Register " + getName());
65  }
66
67  // Keep track of inherited subregs and how they can be reached.
68  SmallVector<Orphan, 8> Orphans;
69
70  // Clone inherited subregs and place duplicate entries on Orphans.
71  // Here the order is important - earlier subregs take precedence.
72  for (unsigned i = 0, e = SubList.size(); i != e; ++i) {
73    CodeGenRegister *SR = RegBank.getReg(SubList[i]);
74    const SubRegMap &Map = SR->getSubRegs(RegBank);
75    for (SubRegMap::const_iterator SI = Map.begin(), SE = Map.end(); SI != SE;
76         ++SI)
77      if (!SubRegs.insert(*SI).second)
78        Orphans.push_back(Orphan(SI->second, Indices[i], SI->first));
79  }
80
81  // Process the composites.
82  ListInit *Comps = TheDef->getValueAsListInit("CompositeIndices");
83  for (unsigned i = 0, e = Comps->size(); i != e; ++i) {
84    DagInit *Pat = dynamic_cast<DagInit*>(Comps->getElement(i));
85    if (!Pat)
86      throw TGError(TheDef->getLoc(), "Invalid dag '" +
87                    Comps->getElement(i)->getAsString() +
88                    "' in CompositeIndices");
89    DefInit *BaseIdxInit = dynamic_cast<DefInit*>(Pat->getOperator());
90    if (!BaseIdxInit || !BaseIdxInit->getDef()->isSubClassOf("SubRegIndex"))
91      throw TGError(TheDef->getLoc(), "Invalid SubClassIndex in " +
92                    Pat->getAsString());
93
94    // Resolve list of subreg indices into R2.
95    CodeGenRegister *R2 = this;
96    for (DagInit::const_arg_iterator di = Pat->arg_begin(),
97         de = Pat->arg_end(); di != de; ++di) {
98      DefInit *IdxInit = dynamic_cast<DefInit*>(*di);
99      if (!IdxInit || !IdxInit->getDef()->isSubClassOf("SubRegIndex"))
100        throw TGError(TheDef->getLoc(), "Invalid SubClassIndex in " +
101                      Pat->getAsString());
102      const SubRegMap &R2Subs = R2->getSubRegs(RegBank);
103      SubRegMap::const_iterator ni = R2Subs.find(IdxInit->getDef());
104      if (ni == R2Subs.end())
105        throw TGError(TheDef->getLoc(), "Composite " + Pat->getAsString() +
106                      " refers to bad index in " + R2->getName());
107      R2 = ni->second;
108    }
109
110    // Insert composite index. Allow overriding inherited indices etc.
111    SubRegs[BaseIdxInit->getDef()] = R2;
112
113    // R2 is no longer an orphan.
114    for (unsigned j = 0, je = Orphans.size(); j != je; ++j)
115      if (Orphans[j].SubReg == R2)
116          Orphans[j].SubReg = 0;
117  }
118
119  // Now Orphans contains the inherited subregisters without a direct index.
120  // Create inferred indexes for all missing entries.
121  for (unsigned i = 0, e = Orphans.size(); i != e; ++i) {
122    Orphan &O = Orphans[i];
123    if (!O.SubReg)
124      continue;
125    SubRegs[RegBank.getCompositeSubRegIndex(O.First, O.Second, true)] =
126      O.SubReg;
127  }
128  return SubRegs;
129}
130
131//===----------------------------------------------------------------------===//
132//                            CodeGenRegisterClass
133//===----------------------------------------------------------------------===//
134
135CodeGenRegisterClass::CodeGenRegisterClass(Record *R) : TheDef(R) {
136  // Rename anonymous register classes.
137  if (R->getName().size() > 9 && R->getName()[9] == '.') {
138    static unsigned AnonCounter = 0;
139    R->setName("AnonRegClass_"+utostr(AnonCounter++));
140  }
141
142  std::vector<Record*> TypeList = R->getValueAsListOfDefs("RegTypes");
143  for (unsigned i = 0, e = TypeList.size(); i != e; ++i) {
144    Record *Type = TypeList[i];
145    if (!Type->isSubClassOf("ValueType"))
146      throw "RegTypes list member '" + Type->getName() +
147        "' does not derive from the ValueType class!";
148    VTs.push_back(getValueType(Type));
149  }
150  assert(!VTs.empty() && "RegisterClass must contain at least one ValueType!");
151
152  std::vector<Record*> RegList = R->getValueAsListOfDefs("MemberList");
153  for (unsigned i = 0, e = RegList.size(); i != e; ++i) {
154    Record *Reg = RegList[i];
155    if (!Reg->isSubClassOf("Register"))
156      throw "Register Class member '" + Reg->getName() +
157            "' does not derive from the Register class!";
158    Elements.push_back(Reg);
159  }
160
161  // SubRegClasses is a list<dag> containing (RC, subregindex, ...) dags.
162  ListInit *SRC = R->getValueAsListInit("SubRegClasses");
163  for (ListInit::const_iterator i = SRC->begin(), e = SRC->end(); i != e; ++i) {
164    DagInit *DAG = dynamic_cast<DagInit*>(*i);
165    if (!DAG) throw "SubRegClasses must contain DAGs";
166    DefInit *DAGOp = dynamic_cast<DefInit*>(DAG->getOperator());
167    Record *RCRec;
168    if (!DAGOp || !(RCRec = DAGOp->getDef())->isSubClassOf("RegisterClass"))
169      throw "Operator '" + DAG->getOperator()->getAsString() +
170        "' in SubRegClasses is not a RegisterClass";
171    // Iterate over args, all SubRegIndex instances.
172    for (DagInit::const_arg_iterator ai = DAG->arg_begin(), ae = DAG->arg_end();
173         ai != ae; ++ai) {
174      DefInit *Idx = dynamic_cast<DefInit*>(*ai);
175      Record *IdxRec;
176      if (!Idx || !(IdxRec = Idx->getDef())->isSubClassOf("SubRegIndex"))
177        throw "Argument '" + (*ai)->getAsString() +
178          "' in SubRegClasses is not a SubRegIndex";
179      if (!SubRegClasses.insert(std::make_pair(IdxRec, RCRec)).second)
180        throw "SubRegIndex '" + IdxRec->getName() + "' mentioned twice";
181    }
182  }
183
184  // Allow targets to override the size in bits of the RegisterClass.
185  unsigned Size = R->getValueAsInt("Size");
186
187  Namespace = R->getValueAsString("Namespace");
188  SpillSize = Size ? Size : EVT(VTs[0]).getSizeInBits();
189  SpillAlignment = R->getValueAsInt("Alignment");
190  CopyCost = R->getValueAsInt("CopyCost");
191  Allocatable = R->getValueAsBit("isAllocatable");
192  MethodBodies = R->getValueAsCode("MethodBodies");
193  MethodProtos = R->getValueAsCode("MethodProtos");
194}
195
196const std::string &CodeGenRegisterClass::getName() const {
197  return TheDef->getName();
198}
199
200//===----------------------------------------------------------------------===//
201//                               CodeGenRegBank
202//===----------------------------------------------------------------------===//
203
204CodeGenRegBank::CodeGenRegBank(RecordKeeper &Records) : Records(Records) {
205  // Read in the user-defined (named) sub-register indices.
206  // More indices will be synthesized later.
207  SubRegIndices = Records.getAllDerivedDefinitions("SubRegIndex");
208  std::sort(SubRegIndices.begin(), SubRegIndices.end(), LessRecord());
209  NumNamedIndices = SubRegIndices.size();
210
211  // Read in the register definitions.
212  std::vector<Record*> Regs = Records.getAllDerivedDefinitions("Register");
213  std::sort(Regs.begin(), Regs.end(), LessRecord());
214  Registers.reserve(Regs.size());
215  // Assign the enumeration values.
216  for (unsigned i = 0, e = Regs.size(); i != e; ++i)
217    Registers.push_back(CodeGenRegister(Regs[i], i + 1));
218}
219
220CodeGenRegister *CodeGenRegBank::getReg(Record *Def) {
221  if (Def2Reg.empty())
222    for (unsigned i = 0, e = Registers.size(); i != e; ++i)
223      Def2Reg[Registers[i].TheDef] = &Registers[i];
224
225  if (CodeGenRegister *Reg = Def2Reg[Def])
226    return Reg;
227
228  throw TGError(Def->getLoc(), "Not a known Register!");
229}
230
231Record *CodeGenRegBank::getCompositeSubRegIndex(Record *A, Record *B,
232                                                bool create) {
233  // Look for an existing entry.
234  Record *&Comp = Composite[std::make_pair(A, B)];
235  if (Comp || !create)
236    return Comp;
237
238  // None exists, synthesize one.
239  std::string Name = A->getName() + "_then_" + B->getName();
240  Comp = new Record(Name, SMLoc(), Records);
241  Records.addDef(Comp);
242  SubRegIndices.push_back(Comp);
243  return Comp;
244}
245
246unsigned CodeGenRegBank::getSubRegIndexNo(Record *idx) {
247  std::vector<Record*>::const_iterator i =
248    std::find(SubRegIndices.begin(), SubRegIndices.end(), idx);
249  assert(i != SubRegIndices.end() && "Not a SubRegIndex");
250  return (i - SubRegIndices.begin()) + 1;
251}
252
253void CodeGenRegBank::computeComposites() {
254  // Precompute all sub-register maps. This will create Composite entries for
255  // all inferred sub-register indices.
256  for (unsigned i = 0, e = Registers.size(); i != e; ++i)
257    Registers[i].getSubRegs(*this);
258
259  for (unsigned i = 0, e = Registers.size(); i != e; ++i) {
260    CodeGenRegister *Reg1 = &Registers[i];
261    const CodeGenRegister::SubRegMap &SRM1 = Reg1->getSubRegs(*this);
262    for (CodeGenRegister::SubRegMap::const_iterator i1 = SRM1.begin(),
263         e1 = SRM1.end(); i1 != e1; ++i1) {
264      Record *Idx1 = i1->first;
265      CodeGenRegister *Reg2 = i1->second;
266      // Ignore identity compositions.
267      if (Reg1 == Reg2)
268        continue;
269      const CodeGenRegister::SubRegMap &SRM2 = Reg2->getSubRegs(*this);
270      // Try composing Idx1 with another SubRegIndex.
271      for (CodeGenRegister::SubRegMap::const_iterator i2 = SRM2.begin(),
272           e2 = SRM2.end(); i2 != e2; ++i2) {
273        std::pair<Record*, Record*> IdxPair(Idx1, i2->first);
274        CodeGenRegister *Reg3 = i2->second;
275        // Ignore identity compositions.
276        if (Reg2 == Reg3)
277          continue;
278        // OK Reg1:IdxPair == Reg3. Find the index with Reg:Idx == Reg3.
279        for (CodeGenRegister::SubRegMap::const_iterator i1d = SRM1.begin(),
280             e1d = SRM1.end(); i1d != e1d; ++i1d) {
281          if (i1d->second == Reg3) {
282            std::pair<CompositeMap::iterator, bool> Ins =
283              Composite.insert(std::make_pair(IdxPair, i1d->first));
284            // Conflicting composition? Emit a warning but allow it.
285            if (!Ins.second && Ins.first->second != i1d->first) {
286              errs() << "Warning: SubRegIndex " << getQualifiedName(Idx1)
287                     << " and " << getQualifiedName(IdxPair.second)
288                     << " compose ambiguously as "
289                     << getQualifiedName(Ins.first->second) << " or "
290                     << getQualifiedName(i1d->first) << "\n";
291            }
292          }
293        }
294      }
295    }
296  }
297
298  // We don't care about the difference between (Idx1, Idx2) -> Idx2 and invalid
299  // compositions, so remove any mappings of that form.
300  for (CompositeMap::iterator i = Composite.begin(), e = Composite.end();
301       i != e;) {
302    CompositeMap::iterator j = i;
303    ++i;
304    if (j->first.second == j->second)
305      Composite.erase(j);
306  }
307}
308
309void CodeGenRegBank::computeDerivedInfo() {
310  computeComposites();
311}
312
313