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 // Get a map of sub-registers computed lazily.
104 // This includes unique entries for all sub-sub-registers.
105 const SubRegMap &getSubRegs(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 // List of super-registers in topological order, small to large.
117 typedef std::vector<const CodeGenRegister*> SuperRegList;
119 // Get the list of super-registers. This is valid after getSubReg
120 // visits all registers during RegBank construction.
121 const SuperRegList &getSuperRegs() const {
122 assert(SubRegsComplete && "Must precompute sub-registers");
126 // List of register units in ascending order.
127 typedef SmallVector<unsigned, 16> RegUnitList;
129 // Get the list of register units.
130 // This is only valid after getSubRegs() completes.
131 const RegUnitList &getRegUnits() const { return RegUnits; }
133 // Inherit register units from subregisters.
134 // Return true if the RegUnits changed.
135 bool inheritRegUnits(CodeGenRegBank &RegBank);
137 // Adopt a register unit for pressure tracking.
138 // A unit is adopted iff its unit number is >= NumNativeRegUnits.
139 void adoptRegUnit(unsigned RUID) { RegUnits.push_back(RUID); }
141 // Get the sum of this register's register unit weights.
142 unsigned getWeight(const CodeGenRegBank &RegBank) const;
144 // Order CodeGenRegister pointers by EnumValue.
146 bool operator()(const CodeGenRegister *A,
147 const CodeGenRegister *B) const {
149 return A->EnumValue < B->EnumValue;
153 // Canonically ordered set.
154 typedef std::set<const CodeGenRegister*, Less> Set;
157 bool SubRegsComplete;
159 SuperRegList SuperRegs;
160 RegUnitList RegUnits;
164 class CodeGenRegisterClass {
165 CodeGenRegister::Set Members;
166 // Allocation orders. Order[0] always contains all registers in Members.
167 std::vector<SmallVector<Record*, 16> > Orders;
168 // Bit mask of sub-classes including this, indexed by their EnumValue.
169 BitVector SubClasses;
170 // List of super-classes, topologocally ordered to have the larger classes
171 // first. This is the same as sorting by EnumValue.
172 SmallVector<CodeGenRegisterClass*, 4> SuperClasses;
176 // For a synthesized class, inherit missing properties from the nearest
178 void inheritProperties(CodeGenRegBank&);
180 // Map SubRegIndex -> sub-class. This is the largest sub-class where all
181 // registers have a SubRegIndex sub-register.
182 DenseMap<CodeGenSubRegIndex*, CodeGenRegisterClass*> SubClassWithSubReg;
184 // Map SubRegIndex -> set of super-reg classes. This is all register
185 // classes SuperRC such that:
187 // R:SubRegIndex in this RC for all R in SuperRC.
189 DenseMap<CodeGenSubRegIndex*,
190 SmallPtrSet<CodeGenRegisterClass*, 8> > SuperRegClasses;
194 std::string Namespace;
195 std::vector<MVT::SimpleValueType> VTs;
197 unsigned SpillAlignment;
200 std::string AltOrderSelect;
202 // Return the Record that defined this class, or NULL if the class was
203 // created by TableGen.
204 Record *getDef() const { return TheDef; }
206 const std::string &getName() const { return Name; }
207 std::string getQualifiedName() const;
208 const std::vector<MVT::SimpleValueType> &getValueTypes() const {return VTs;}
209 unsigned getNumValueTypes() const { return VTs.size(); }
211 MVT::SimpleValueType getValueTypeNum(unsigned VTNum) const {
212 if (VTNum < VTs.size())
214 llvm_unreachable("VTNum greater than number of ValueTypes in RegClass!");
217 // Return true if this this class contains the register.
218 bool contains(const CodeGenRegister*) const;
220 // Returns true if RC is a subclass.
221 // RC is a sub-class of this class if it is a valid replacement for any
222 // instruction operand where a register of this classis required. It must
223 // satisfy these conditions:
225 // 1. All RC registers are also in this.
226 // 2. The RC spill size must not be smaller than our spill size.
227 // 3. RC spill alignment must be compatible with ours.
229 bool hasSubClass(const CodeGenRegisterClass *RC) const {
230 return SubClasses.test(RC->EnumValue);
233 // getSubClassWithSubReg - Returns the largest sub-class where all
234 // registers have a SubIdx sub-register.
235 CodeGenRegisterClass*
236 getSubClassWithSubReg(CodeGenSubRegIndex *SubIdx) const {
237 return SubClassWithSubReg.lookup(SubIdx);
240 void setSubClassWithSubReg(CodeGenSubRegIndex *SubIdx,
241 CodeGenRegisterClass *SubRC) {
242 SubClassWithSubReg[SubIdx] = SubRC;
245 // getSuperRegClasses - Returns a bit vector of all register classes
246 // containing only SubIdx super-registers of this class.
247 void getSuperRegClasses(CodeGenSubRegIndex *SubIdx, BitVector &Out) const;
249 // addSuperRegClass - Add a class containing only SudIdx super-registers.
250 void addSuperRegClass(CodeGenSubRegIndex *SubIdx,
251 CodeGenRegisterClass *SuperRC) {
252 SuperRegClasses[SubIdx].insert(SuperRC);
255 // getSubClasses - Returns a constant BitVector of subclasses indexed by
257 // The SubClasses vector includs an entry for this class.
258 const BitVector &getSubClasses() const { return SubClasses; }
260 // getSuperClasses - Returns a list of super classes ordered by EnumValue.
261 // The array does not include an entry for this class.
262 ArrayRef<CodeGenRegisterClass*> getSuperClasses() const {
266 // Returns an ordered list of class members.
267 // The order of registers is the same as in the .td file.
268 // No = 0 is the default allocation order, No = 1 is the first alternative.
269 ArrayRef<Record*> getOrder(unsigned No = 0) const {
273 // Return the total number of allocation orders available.
274 unsigned getNumOrders() const { return Orders.size(); }
276 // Get the set of registers. This set contains the same registers as
278 const CodeGenRegister::Set &getMembers() const { return Members; }
280 // Populate a unique sorted list of units from a register set.
281 void buildRegUnitSet(std::vector<unsigned> &RegUnits) const;
283 CodeGenRegisterClass(CodeGenRegBank&, Record *R);
285 // A key representing the parts of a register class used for forming
286 // sub-classes. Note the ordering provided by this key is not the same as
287 // the topological order used for the EnumValues.
289 const CodeGenRegister::Set *Members;
291 unsigned SpillAlignment;
294 : Members(O.Members),
295 SpillSize(O.SpillSize),
296 SpillAlignment(O.SpillAlignment) {}
298 Key(const CodeGenRegister::Set *M, unsigned S = 0, unsigned A = 0)
299 : Members(M), SpillSize(S), SpillAlignment(A) {}
301 Key(const CodeGenRegisterClass &RC)
302 : Members(&RC.getMembers()),
303 SpillSize(RC.SpillSize),
304 SpillAlignment(RC.SpillAlignment) {}
306 // Lexicographical order of (Members, SpillSize, SpillAlignment).
307 bool operator<(const Key&) const;
310 // Create a non-user defined register class.
311 CodeGenRegisterClass(StringRef Name, Key Props);
313 // Called by CodeGenRegBank::CodeGenRegBank().
314 static void computeSubClasses(CodeGenRegBank&);
317 // Each RegUnitSet is a sorted vector with a name.
319 typedef std::vector<unsigned>::const_iterator iterator;
322 std::vector<unsigned> Units;
325 // CodeGenRegBank - Represent a target's registers and the relations between
327 class CodeGenRegBank {
328 RecordKeeper &Records;
332 std::vector<CodeGenSubRegIndex*> SubRegIndices;
333 DenseMap<Record*, CodeGenSubRegIndex*> Def2SubRegIdx;
334 unsigned NumNamedIndices;
337 std::vector<CodeGenRegister*> Registers;
338 DenseMap<Record*, CodeGenRegister*> Def2Reg;
339 unsigned NumNativeRegUnits;
340 unsigned NumRegUnits; // # native + adopted register units.
342 // Map each register unit to a weight (for register pressure).
343 // Includes native and adopted register units.
344 std::vector<unsigned> RegUnitWeights;
347 std::vector<CodeGenRegisterClass*> RegClasses;
348 DenseMap<Record*, CodeGenRegisterClass*> Def2RC;
349 typedef std::map<CodeGenRegisterClass::Key, CodeGenRegisterClass*> RCKeyMap;
352 // Remember each unique set of register units. Initially, this contains a
353 // unique set for each register class. Simliar sets are coalesced with
354 // pruneUnitSets and new supersets are inferred during computeRegUnitSets.
355 std::vector<RegUnitSet> RegUnitSets;
357 // Map RegisterClass index to the index of the RegUnitSet that contains the
358 // class's units and any inferred RegUnit supersets.
359 std::vector<std::vector<unsigned> > RegClassUnitSets;
361 // Add RC to *2RC maps.
362 void addToMaps(CodeGenRegisterClass*);
364 // Create a synthetic sub-class if it is missing.
365 CodeGenRegisterClass *getOrCreateSubClass(const CodeGenRegisterClass *RC,
366 const CodeGenRegister::Set *Membs,
369 // Infer missing register classes.
370 void computeInferredRegisterClasses();
371 void inferCommonSubClass(CodeGenRegisterClass *RC);
372 void inferSubClassWithSubReg(CodeGenRegisterClass *RC);
373 void inferMatchingSuperRegClass(CodeGenRegisterClass *RC,
374 unsigned FirstSubRegRC = 0);
376 // Iteratively prune unit sets.
377 void pruneUnitSets();
379 // Compute a weight for each register unit created during getSubRegs.
380 void computeRegUnitWeights();
382 // Create a RegUnitSet for each RegClass and infer superclasses.
383 void computeRegUnitSets();
385 // Populate the Composite map from sub-register relationships.
386 void computeComposites();
389 CodeGenRegBank(RecordKeeper&);
391 SetTheory &getSets() { return Sets; }
393 // Sub-register indices. The first NumNamedIndices are defined by the user
394 // in the .td files. The rest are synthesized such that all sub-registers
395 // have a unique name.
396 ArrayRef<CodeGenSubRegIndex*> getSubRegIndices() { return SubRegIndices; }
397 unsigned getNumNamedIndices() { return NumNamedIndices; }
399 // Find a SubRegIndex form its Record def.
400 CodeGenSubRegIndex *getSubRegIdx(Record*);
402 // Find or create a sub-register index representing the A+B composition.
403 CodeGenSubRegIndex *getCompositeSubRegIndex(CodeGenSubRegIndex *A,
404 CodeGenSubRegIndex *B);
406 const std::vector<CodeGenRegister*> &getRegisters() { return Registers; }
408 // Find a register from its Record def.
409 CodeGenRegister *getReg(Record*);
411 // Get a Register's index into the Registers array.
412 unsigned getRegIndex(const CodeGenRegister *Reg) const {
413 return Reg->EnumValue - 1;
416 // Create a new non-native register unit that can be adopted by a register
417 // to increase its pressure. Note that NumNativeRegUnits is not increased.
418 unsigned newRegUnit(unsigned Weight) {
419 if (!RegUnitWeights.empty()) {
420 assert(Weight && "should only add allocatable units");
421 RegUnitWeights.resize(NumRegUnits+1);
422 RegUnitWeights[NumRegUnits] = Weight;
424 return NumRegUnits++;
427 // Native units are the singular unit of a leaf register. Register aliasing
428 // is completely characterized by native units. Adopted units exist to give
429 // register additional weight but don't affect aliasing.
430 bool isNativeUnit(unsigned RUID) {
431 return RUID < NumNativeRegUnits;
434 ArrayRef<CodeGenRegisterClass*> getRegClasses() const {
438 // Find a register class from its def.
439 CodeGenRegisterClass *getRegClass(Record*);
441 /// getRegisterClassForRegister - Find the register class that contains the
442 /// specified physical register. If the register is not in a register
443 /// class, return null. If the register is in multiple classes, and the
444 /// classes have a superset-subset relationship and the same set of types,
445 /// return the superclass. Otherwise return null.
446 const CodeGenRegisterClass* getRegClassForRegister(Record *R);
448 // Get a register unit's weight. Zero for unallocatable registers.
449 unsigned getRegUnitWeight(unsigned RUID) const {
450 return RegUnitWeights[RUID];
453 // Get the sum of unit weights.
454 unsigned getRegUnitSetWeight(const std::vector<unsigned> &Units) const {
456 for (std::vector<unsigned>::const_iterator
457 I = Units.begin(), E = Units.end(); I != E; ++I)
458 Weight += getRegUnitWeight(*I);
462 // Increase a RegUnitWeight.
463 void increaseRegUnitWeight(unsigned RUID, unsigned Inc) {
464 RegUnitWeights[RUID] += Inc;
467 // Get the number of register pressure dimensions.
468 unsigned getNumRegPressureSets() const { return RegUnitSets.size(); }
470 // Get a set of register unit IDs for a given dimension of pressure.
471 RegUnitSet getRegPressureSet(unsigned Idx) const {
472 return RegUnitSets[Idx];
475 // Get a list of pressure set IDs for a register class. Liveness of a
476 // register in this class impacts each pressure set in this list by the
477 // weight of the register. An exact solution requires all registers in a
478 // class to have the same class, but it is not strictly guaranteed.
479 ArrayRef<unsigned> getRCPressureSetIDs(unsigned RCIdx) const {
480 return RegClassUnitSets[RCIdx];
483 // Computed derived records such as missing sub-register indices.
484 void computeDerivedInfo();
486 // Compute full overlap sets for every register. These sets include the
487 // rarely used aliases that are neither sub nor super-registers.
489 // Map[R1].count(R2) is reflexive and symmetric, but not transitive.
491 // If R1 is a sub-register of R2, Map[R1] is a subset of Map[R2].
492 void computeOverlaps(std::map<const CodeGenRegister*,
493 CodeGenRegister::Set> &Map);
495 // Compute the set of registers completely covered by the registers in Regs.
496 // The returned BitVector will have a bit set for each register in Regs,
497 // all sub-registers, and all super-registers that are covered by the
498 // registers in Regs.
500 // This is used to compute the mask of call-preserved registers from a list
502 BitVector computeCoveredRegisters(ArrayRef<Record*> Regs);