1 //===- CodeGenRegisters.h - Register and RegisterClass Info -----*- C++ -*-===//
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 defines structures to encapsulate information gleaned from the
11 // target register and register class definitions.
13 //===----------------------------------------------------------------------===//
15 #ifndef CODEGEN_REGISTERS_H
16 #define CODEGEN_REGISTERS_H
18 #include "SetTheory.h"
19 #include "llvm/TableGen/Record.h"
20 #include "llvm/CodeGen/ValueTypes.h"
21 #include "llvm/ADT/ArrayRef.h"
22 #include "llvm/ADT/BitVector.h"
23 #include "llvm/ADT/DenseMap.h"
24 #include "llvm/ADT/SetVector.h"
25 #include "llvm/Support/ErrorHandling.h"
35 /// CodeGenSubRegIndex - Represents a sub-register index.
36 class CodeGenSubRegIndex {
38 const unsigned EnumValue;
41 CodeGenSubRegIndex(Record *R, unsigned Enum);
43 const std::string &getName() const;
44 std::string getNamespace() const;
45 std::string getQualifiedName() const;
47 // Order CodeGenSubRegIndex pointers by EnumValue.
49 bool operator()(const CodeGenSubRegIndex *A,
50 const CodeGenSubRegIndex *B) const {
52 return A->EnumValue < B->EnumValue;
56 // Map of composite subreg indices.
57 typedef std::map<CodeGenSubRegIndex*, CodeGenSubRegIndex*, Less> CompMap;
59 // Returns the subreg index that results from composing this with Idx.
60 // Returns NULL if this and Idx don't compose.
61 CodeGenSubRegIndex *compose(CodeGenSubRegIndex *Idx) const {
62 CompMap::const_iterator I = Composed.find(Idx);
63 return I == Composed.end() ? 0 : I->second;
66 // Add a composite subreg index: this+A = B.
67 // Return a conflicting composite, or NULL
68 CodeGenSubRegIndex *addComposite(CodeGenSubRegIndex *A,
69 CodeGenSubRegIndex *B) {
70 std::pair<CompMap::iterator, bool> Ins =
71 Composed.insert(std::make_pair(A, B));
72 return (Ins.second || Ins.first->second == B) ? 0 : Ins.first->second;
75 // Update the composite maps of components specified in 'ComposedOf'.
76 void updateComponents(CodeGenRegBank&);
78 // Clean out redundant composite mappings.
79 void cleanComposites();
81 // Return the map of composites.
82 const CompMap &getComposites() const { return Composed; }
88 /// CodeGenRegister - Represents a register definition.
89 struct CodeGenRegister {
93 bool CoveredBySubRegs;
95 // Map SubRegIndex -> Register.
96 typedef std::map<CodeGenSubRegIndex*, CodeGenRegister*,
97 CodeGenSubRegIndex::Less> SubRegMap;
99 CodeGenRegister(Record *R, unsigned Enum);
101 const std::string &getName() const;
103 // Lazily compute a map of all sub-registers.
104 // This includes unique entries for all sub-sub-registers.
105 const SubRegMap &computeSubRegs(CodeGenRegBank&);
107 const SubRegMap &getSubRegs() const {
108 assert(SubRegsComplete && "Must precompute sub-registers");
112 // Add sub-registers to OSet following a pre-order defined by the .td file.
113 void addSubRegsPreOrder(SetVector<const CodeGenRegister*> &OSet,
114 CodeGenRegBank&) const;
116 // Return the sub-register index naming Reg as a sub-register of this
117 // register. Returns NULL if Reg is not a sub-register.
118 CodeGenSubRegIndex *getSubRegIndex(const CodeGenRegister *Reg) const {
119 return SubReg2Idx.lookup(Reg);
122 // List of super-registers in topological order, small to large.
123 typedef std::vector<const CodeGenRegister*> SuperRegList;
125 // Get the list of super-registers. This is valid after getSubReg
126 // visits all registers during RegBank construction.
127 const SuperRegList &getSuperRegs() const {
128 assert(SubRegsComplete && "Must precompute sub-registers");
132 // List of register units in ascending order.
133 typedef SmallVector<unsigned, 16> RegUnitList;
135 // Get the list of register units.
136 // This is only valid after getSubRegs() completes.
137 const RegUnitList &getRegUnits() const { return RegUnits; }
139 // Inherit register units from subregisters.
140 // Return true if the RegUnits changed.
141 bool inheritRegUnits(CodeGenRegBank &RegBank);
143 // Adopt a register unit for pressure tracking.
144 // A unit is adopted iff its unit number is >= NumNativeRegUnits.
145 void adoptRegUnit(unsigned RUID) { RegUnits.push_back(RUID); }
147 // Get the sum of this register's register unit weights.
148 unsigned getWeight(const CodeGenRegBank &RegBank) const;
150 // Order CodeGenRegister pointers by EnumValue.
152 bool operator()(const CodeGenRegister *A,
153 const CodeGenRegister *B) const {
155 return A->EnumValue < B->EnumValue;
159 // Canonically ordered set.
160 typedef std::set<const CodeGenRegister*, Less> Set;
163 bool SubRegsComplete;
165 SuperRegList SuperRegs;
166 DenseMap<const CodeGenRegister*, CodeGenSubRegIndex*> SubReg2Idx;
167 RegUnitList RegUnits;
171 class CodeGenRegisterClass {
172 CodeGenRegister::Set Members;
173 // Allocation orders. Order[0] always contains all registers in Members.
174 std::vector<SmallVector<Record*, 16> > Orders;
175 // Bit mask of sub-classes including this, indexed by their EnumValue.
176 BitVector SubClasses;
177 // List of super-classes, topologocally ordered to have the larger classes
178 // first. This is the same as sorting by EnumValue.
179 SmallVector<CodeGenRegisterClass*, 4> SuperClasses;
183 // For a synthesized class, inherit missing properties from the nearest
185 void inheritProperties(CodeGenRegBank&);
187 // Map SubRegIndex -> sub-class. This is the largest sub-class where all
188 // registers have a SubRegIndex sub-register.
189 DenseMap<CodeGenSubRegIndex*, CodeGenRegisterClass*> SubClassWithSubReg;
191 // Map SubRegIndex -> set of super-reg classes. This is all register
192 // classes SuperRC such that:
194 // R:SubRegIndex in this RC for all R in SuperRC.
196 DenseMap<CodeGenSubRegIndex*,
197 SmallPtrSet<CodeGenRegisterClass*, 8> > SuperRegClasses;
201 std::string Namespace;
202 std::vector<MVT::SimpleValueType> VTs;
204 unsigned SpillAlignment;
207 std::string AltOrderSelect;
209 // Return the Record that defined this class, or NULL if the class was
210 // created by TableGen.
211 Record *getDef() const { return TheDef; }
213 const std::string &getName() const { return Name; }
214 std::string getQualifiedName() const;
215 const std::vector<MVT::SimpleValueType> &getValueTypes() const {return VTs;}
216 unsigned getNumValueTypes() const { return VTs.size(); }
218 MVT::SimpleValueType getValueTypeNum(unsigned VTNum) const {
219 if (VTNum < VTs.size())
221 llvm_unreachable("VTNum greater than number of ValueTypes in RegClass!");
224 // Return true if this this class contains the register.
225 bool contains(const CodeGenRegister*) const;
227 // Returns true if RC is a subclass.
228 // RC is a sub-class of this class if it is a valid replacement for any
229 // instruction operand where a register of this classis required. It must
230 // satisfy these conditions:
232 // 1. All RC registers are also in this.
233 // 2. The RC spill size must not be smaller than our spill size.
234 // 3. RC spill alignment must be compatible with ours.
236 bool hasSubClass(const CodeGenRegisterClass *RC) const {
237 return SubClasses.test(RC->EnumValue);
240 // getSubClassWithSubReg - Returns the largest sub-class where all
241 // registers have a SubIdx sub-register.
242 CodeGenRegisterClass*
243 getSubClassWithSubReg(CodeGenSubRegIndex *SubIdx) const {
244 return SubClassWithSubReg.lookup(SubIdx);
247 void setSubClassWithSubReg(CodeGenSubRegIndex *SubIdx,
248 CodeGenRegisterClass *SubRC) {
249 SubClassWithSubReg[SubIdx] = SubRC;
252 // getSuperRegClasses - Returns a bit vector of all register classes
253 // containing only SubIdx super-registers of this class.
254 void getSuperRegClasses(CodeGenSubRegIndex *SubIdx, BitVector &Out) const;
256 // addSuperRegClass - Add a class containing only SudIdx super-registers.
257 void addSuperRegClass(CodeGenSubRegIndex *SubIdx,
258 CodeGenRegisterClass *SuperRC) {
259 SuperRegClasses[SubIdx].insert(SuperRC);
262 // getSubClasses - Returns a constant BitVector of subclasses indexed by
264 // The SubClasses vector includs an entry for this class.
265 const BitVector &getSubClasses() const { return SubClasses; }
267 // getSuperClasses - Returns a list of super classes ordered by EnumValue.
268 // The array does not include an entry for this class.
269 ArrayRef<CodeGenRegisterClass*> getSuperClasses() const {
273 // Returns an ordered list of class members.
274 // The order of registers is the same as in the .td file.
275 // No = 0 is the default allocation order, No = 1 is the first alternative.
276 ArrayRef<Record*> getOrder(unsigned No = 0) const {
280 // Return the total number of allocation orders available.
281 unsigned getNumOrders() const { return Orders.size(); }
283 // Get the set of registers. This set contains the same registers as
285 const CodeGenRegister::Set &getMembers() const { return Members; }
287 // Populate a unique sorted list of units from a register set.
288 void buildRegUnitSet(std::vector<unsigned> &RegUnits) const;
290 CodeGenRegisterClass(CodeGenRegBank&, Record *R);
292 // A key representing the parts of a register class used for forming
293 // sub-classes. Note the ordering provided by this key is not the same as
294 // the topological order used for the EnumValues.
296 const CodeGenRegister::Set *Members;
298 unsigned SpillAlignment;
301 : Members(O.Members),
302 SpillSize(O.SpillSize),
303 SpillAlignment(O.SpillAlignment) {}
305 Key(const CodeGenRegister::Set *M, unsigned S = 0, unsigned A = 0)
306 : Members(M), SpillSize(S), SpillAlignment(A) {}
308 Key(const CodeGenRegisterClass &RC)
309 : Members(&RC.getMembers()),
310 SpillSize(RC.SpillSize),
311 SpillAlignment(RC.SpillAlignment) {}
313 // Lexicographical order of (Members, SpillSize, SpillAlignment).
314 bool operator<(const Key&) const;
317 // Create a non-user defined register class.
318 CodeGenRegisterClass(StringRef Name, Key Props);
320 // Called by CodeGenRegBank::CodeGenRegBank().
321 static void computeSubClasses(CodeGenRegBank&);
324 // Each RegUnitSet is a sorted vector with a name.
326 typedef std::vector<unsigned>::const_iterator iterator;
329 std::vector<unsigned> Units;
332 // CodeGenRegBank - Represent a target's registers and the relations between
334 class CodeGenRegBank {
335 RecordKeeper &Records;
339 std::vector<CodeGenSubRegIndex*> SubRegIndices;
340 DenseMap<Record*, CodeGenSubRegIndex*> Def2SubRegIdx;
341 unsigned NumNamedIndices;
344 std::vector<CodeGenRegister*> Registers;
345 DenseMap<Record*, CodeGenRegister*> Def2Reg;
346 unsigned NumNativeRegUnits;
347 unsigned NumRegUnits; // # native + adopted register units.
349 // Map each register unit to a weight (for register pressure).
350 // Includes native and adopted register units.
351 std::vector<unsigned> RegUnitWeights;
354 std::vector<CodeGenRegisterClass*> RegClasses;
355 DenseMap<Record*, CodeGenRegisterClass*> Def2RC;
356 typedef std::map<CodeGenRegisterClass::Key, CodeGenRegisterClass*> RCKeyMap;
359 // Remember each unique set of register units. Initially, this contains a
360 // unique set for each register class. Simliar sets are coalesced with
361 // pruneUnitSets and new supersets are inferred during computeRegUnitSets.
362 std::vector<RegUnitSet> RegUnitSets;
364 // Map RegisterClass index to the index of the RegUnitSet that contains the
365 // class's units and any inferred RegUnit supersets.
366 std::vector<std::vector<unsigned> > RegClassUnitSets;
368 // Add RC to *2RC maps.
369 void addToMaps(CodeGenRegisterClass*);
371 // Create a synthetic sub-class if it is missing.
372 CodeGenRegisterClass *getOrCreateSubClass(const CodeGenRegisterClass *RC,
373 const CodeGenRegister::Set *Membs,
376 // Infer missing register classes.
377 void computeInferredRegisterClasses();
378 void inferCommonSubClass(CodeGenRegisterClass *RC);
379 void inferSubClassWithSubReg(CodeGenRegisterClass *RC);
380 void inferMatchingSuperRegClass(CodeGenRegisterClass *RC,
381 unsigned FirstSubRegRC = 0);
383 // Iteratively prune unit sets.
384 void pruneUnitSets();
386 // Compute a weight for each register unit created during getSubRegs.
387 void computeRegUnitWeights();
389 // Create a RegUnitSet for each RegClass and infer superclasses.
390 void computeRegUnitSets();
392 // Populate the Composite map from sub-register relationships.
393 void computeComposites();
396 CodeGenRegBank(RecordKeeper&);
398 SetTheory &getSets() { return Sets; }
400 // Sub-register indices. The first NumNamedIndices are defined by the user
401 // in the .td files. The rest are synthesized such that all sub-registers
402 // have a unique name.
403 ArrayRef<CodeGenSubRegIndex*> getSubRegIndices() { return SubRegIndices; }
404 unsigned getNumNamedIndices() { return NumNamedIndices; }
406 // Find a SubRegIndex form its Record def.
407 CodeGenSubRegIndex *getSubRegIdx(Record*);
409 // Find or create a sub-register index representing the A+B composition.
410 CodeGenSubRegIndex *getCompositeSubRegIndex(CodeGenSubRegIndex *A,
411 CodeGenSubRegIndex *B);
413 const std::vector<CodeGenRegister*> &getRegisters() { return Registers; }
415 // Find a register from its Record def.
416 CodeGenRegister *getReg(Record*);
418 // Get a Register's index into the Registers array.
419 unsigned getRegIndex(const CodeGenRegister *Reg) const {
420 return Reg->EnumValue - 1;
423 // Create a new non-native register unit that can be adopted by a register
424 // to increase its pressure. Note that NumNativeRegUnits is not increased.
425 unsigned newRegUnit(unsigned Weight) {
426 if (!RegUnitWeights.empty()) {
427 assert(Weight && "should only add allocatable units");
428 RegUnitWeights.resize(NumRegUnits+1);
429 RegUnitWeights[NumRegUnits] = Weight;
431 return NumRegUnits++;
434 // Native units are the singular unit of a leaf register. Register aliasing
435 // is completely characterized by native units. Adopted units exist to give
436 // register additional weight but don't affect aliasing.
437 bool isNativeUnit(unsigned RUID) {
438 return RUID < NumNativeRegUnits;
441 ArrayRef<CodeGenRegisterClass*> getRegClasses() const {
445 // Find a register class from its def.
446 CodeGenRegisterClass *getRegClass(Record*);
448 /// getRegisterClassForRegister - Find the register class that contains the
449 /// specified physical register. If the register is not in a register
450 /// class, return null. If the register is in multiple classes, and the
451 /// classes have a superset-subset relationship and the same set of types,
452 /// return the superclass. Otherwise return null.
453 const CodeGenRegisterClass* getRegClassForRegister(Record *R);
455 // Get a register unit's weight. Zero for unallocatable registers.
456 unsigned getRegUnitWeight(unsigned RUID) const {
457 return RegUnitWeights[RUID];
460 // Get the sum of unit weights.
461 unsigned getRegUnitSetWeight(const std::vector<unsigned> &Units) const {
463 for (std::vector<unsigned>::const_iterator
464 I = Units.begin(), E = Units.end(); I != E; ++I)
465 Weight += getRegUnitWeight(*I);
469 // Increase a RegUnitWeight.
470 void increaseRegUnitWeight(unsigned RUID, unsigned Inc) {
471 RegUnitWeights[RUID] += Inc;
474 // Get the number of register pressure dimensions.
475 unsigned getNumRegPressureSets() const { return RegUnitSets.size(); }
477 // Get a set of register unit IDs for a given dimension of pressure.
478 RegUnitSet getRegPressureSet(unsigned Idx) const {
479 return RegUnitSets[Idx];
482 // Get a list of pressure set IDs for a register class. Liveness of a
483 // register in this class impacts each pressure set in this list by the
484 // weight of the register. An exact solution requires all registers in a
485 // class to have the same class, but it is not strictly guaranteed.
486 ArrayRef<unsigned> getRCPressureSetIDs(unsigned RCIdx) const {
487 return RegClassUnitSets[RCIdx];
490 // Computed derived records such as missing sub-register indices.
491 void computeDerivedInfo();
493 // Compute full overlap sets for every register. These sets include the
494 // rarely used aliases that are neither sub nor super-registers.
496 // Map[R1].count(R2) is reflexive and symmetric, but not transitive.
498 // If R1 is a sub-register of R2, Map[R1] is a subset of Map[R2].
499 void computeOverlaps(std::map<const CodeGenRegister*,
500 CodeGenRegister::Set> &Map);
502 // Compute the set of registers completely covered by the registers in Regs.
503 // The returned BitVector will have a bit set for each register in Regs,
504 // all sub-registers, and all super-registers that are covered by the
505 // registers in Regs.
507 // This is used to compute the mask of call-preserved registers from a list
509 BitVector computeCoveredRegisters(ArrayRef<Record*> Regs);