1 //===- SetTheory.cpp - Generate ordered sets from DAG expressions ---------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements the SetTheory class that computes ordered sets of 10 // Records from DAG expressions. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/ADT/ArrayRef.h" 15 #include "llvm/ADT/SmallVector.h" 16 #include "llvm/ADT/STLExtras.h" 17 #include "llvm/ADT/StringRef.h" 18 #include "llvm/Support/Casting.h" 19 #include "llvm/Support/Format.h" 20 #include "llvm/Support/SMLoc.h" 21 #include "llvm/Support/raw_ostream.h" 22 #include "llvm/TableGen/Error.h" 23 #include "llvm/TableGen/Record.h" 24 #include "llvm/TableGen/SetTheory.h" 25 #include <algorithm> 26 #include <cstdint> 27 #include <string> 28 #include <utility> 29 30 using namespace llvm; 31 32 // Define the standard operators. 33 namespace { 34 35 using RecSet = SetTheory::RecSet; 36 using RecVec = SetTheory::RecVec; 37 38 // (add a, b, ...) Evaluate and union all arguments. 39 struct AddOp : public SetTheory::Operator { 40 void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, 41 ArrayRef<SMLoc> Loc) override { 42 ST.evaluate(Expr->arg_begin(), Expr->arg_end(), Elts, Loc); 43 } 44 }; 45 46 // (sub Add, Sub, ...) Set difference. 47 struct SubOp : public SetTheory::Operator { 48 void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, 49 ArrayRef<SMLoc> Loc) override { 50 if (Expr->arg_size() < 2) 51 PrintFatalError(Loc, "Set difference needs at least two arguments: " + 52 Expr->getAsString()); 53 RecSet Add, Sub; 54 ST.evaluate(*Expr->arg_begin(), Add, Loc); 55 ST.evaluate(Expr->arg_begin() + 1, Expr->arg_end(), Sub, Loc); 56 for (RecSet::iterator I = Add.begin(), E = Add.end(); I != E; ++I) 57 if (!Sub.count(*I)) 58 Elts.insert(*I); 59 } 60 }; 61 62 // (and S1, S2) Set intersection. 63 struct AndOp : public SetTheory::Operator { 64 void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, 65 ArrayRef<SMLoc> Loc) override { 66 if (Expr->arg_size() != 2) 67 PrintFatalError(Loc, "Set intersection requires two arguments: " + 68 Expr->getAsString()); 69 RecSet S1, S2; 70 ST.evaluate(Expr->arg_begin()[0], S1, Loc); 71 ST.evaluate(Expr->arg_begin()[1], S2, Loc); 72 for (RecSet::iterator I = S1.begin(), E = S1.end(); I != E; ++I) 73 if (S2.count(*I)) 74 Elts.insert(*I); 75 } 76 }; 77 78 // SetIntBinOp - Abstract base class for (Op S, N) operators. 79 struct SetIntBinOp : public SetTheory::Operator { 80 virtual void apply2(SetTheory &ST, DagInit *Expr, RecSet &Set, int64_t N, 81 RecSet &Elts, ArrayRef<SMLoc> Loc) = 0; 82 83 void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, 84 ArrayRef<SMLoc> Loc) override { 85 if (Expr->arg_size() != 2) 86 PrintFatalError(Loc, "Operator requires (Op Set, Int) arguments: " + 87 Expr->getAsString()); 88 RecSet Set; 89 ST.evaluate(Expr->arg_begin()[0], Set, Loc); 90 IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[1]); 91 if (!II) 92 PrintFatalError(Loc, "Second argument must be an integer: " + 93 Expr->getAsString()); 94 apply2(ST, Expr, Set, II->getValue(), Elts, Loc); 95 } 96 }; 97 98 // (shl S, N) Shift left, remove the first N elements. 99 struct ShlOp : public SetIntBinOp { 100 void apply2(SetTheory &ST, DagInit *Expr, RecSet &Set, int64_t N, 101 RecSet &Elts, ArrayRef<SMLoc> Loc) override { 102 if (N < 0) 103 PrintFatalError(Loc, "Positive shift required: " + 104 Expr->getAsString()); 105 if (unsigned(N) < Set.size()) 106 Elts.insert(Set.begin() + N, Set.end()); 107 } 108 }; 109 110 // (trunc S, N) Truncate after the first N elements. 111 struct TruncOp : public SetIntBinOp { 112 void apply2(SetTheory &ST, DagInit *Expr, RecSet &Set, int64_t N, 113 RecSet &Elts, ArrayRef<SMLoc> Loc) override { 114 if (N < 0) 115 PrintFatalError(Loc, "Positive length required: " + 116 Expr->getAsString()); 117 if (unsigned(N) > Set.size()) 118 N = Set.size(); 119 Elts.insert(Set.begin(), Set.begin() + N); 120 } 121 }; 122 123 // Left/right rotation. 124 struct RotOp : public SetIntBinOp { 125 const bool Reverse; 126 127 RotOp(bool Rev) : Reverse(Rev) {} 128 129 void apply2(SetTheory &ST, DagInit *Expr, RecSet &Set, int64_t N, 130 RecSet &Elts, ArrayRef<SMLoc> Loc) override { 131 if (Reverse) 132 N = -N; 133 // N > 0 -> rotate left, N < 0 -> rotate right. 134 if (Set.empty()) 135 return; 136 if (N < 0) 137 N = Set.size() - (-N % Set.size()); 138 else 139 N %= Set.size(); 140 Elts.insert(Set.begin() + N, Set.end()); 141 Elts.insert(Set.begin(), Set.begin() + N); 142 } 143 }; 144 145 // (decimate S, N) Pick every N'th element of S. 146 struct DecimateOp : public SetIntBinOp { 147 void apply2(SetTheory &ST, DagInit *Expr, RecSet &Set, int64_t N, 148 RecSet &Elts, ArrayRef<SMLoc> Loc) override { 149 if (N <= 0) 150 PrintFatalError(Loc, "Positive stride required: " + 151 Expr->getAsString()); 152 for (unsigned I = 0; I < Set.size(); I += N) 153 Elts.insert(Set[I]); 154 } 155 }; 156 157 // (interleave S1, S2, ...) Interleave elements of the arguments. 158 struct InterleaveOp : public SetTheory::Operator { 159 void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, 160 ArrayRef<SMLoc> Loc) override { 161 // Evaluate the arguments individually. 162 SmallVector<RecSet, 4> Args(Expr->getNumArgs()); 163 unsigned MaxSize = 0; 164 for (unsigned i = 0, e = Expr->getNumArgs(); i != e; ++i) { 165 ST.evaluate(Expr->getArg(i), Args[i], Loc); 166 MaxSize = std::max(MaxSize, unsigned(Args[i].size())); 167 } 168 // Interleave arguments into Elts. 169 for (unsigned n = 0; n != MaxSize; ++n) 170 for (unsigned i = 0, e = Expr->getNumArgs(); i != e; ++i) 171 if (n < Args[i].size()) 172 Elts.insert(Args[i][n]); 173 } 174 }; 175 176 // (sequence "Format", From, To) Generate a sequence of records by name. 177 struct SequenceOp : public SetTheory::Operator { 178 void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, 179 ArrayRef<SMLoc> Loc) override { 180 int Step = 1; 181 if (Expr->arg_size() > 4) 182 PrintFatalError(Loc, "Bad args to (sequence \"Format\", From, To): " + 183 Expr->getAsString()); 184 else if (Expr->arg_size() == 4) { 185 if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[3])) { 186 Step = II->getValue(); 187 } else 188 PrintFatalError(Loc, "Stride must be an integer: " + 189 Expr->getAsString()); 190 } 191 192 std::string Format; 193 if (StringInit *SI = dyn_cast<StringInit>(Expr->arg_begin()[0])) 194 Format = std::string(SI->getValue()); 195 else 196 PrintFatalError(Loc, "Format must be a string: " + Expr->getAsString()); 197 198 int64_t From, To; 199 if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[1])) 200 From = II->getValue(); 201 else 202 PrintFatalError(Loc, "From must be an integer: " + Expr->getAsString()); 203 if (From < 0 || From >= (1 << 30)) 204 PrintFatalError(Loc, "From out of range"); 205 206 if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[2])) 207 To = II->getValue(); 208 else 209 PrintFatalError(Loc, "To must be an integer: " + Expr->getAsString()); 210 if (To < 0 || To >= (1 << 30)) 211 PrintFatalError(Loc, "To out of range"); 212 213 RecordKeeper &Records = 214 cast<DefInit>(Expr->getOperator())->getDef()->getRecords(); 215 216 Step *= From <= To ? 1 : -1; 217 while (true) { 218 if (Step > 0 && From > To) 219 break; 220 else if (Step < 0 && From < To) 221 break; 222 std::string Name; 223 raw_string_ostream OS(Name); 224 OS << format(Format.c_str(), unsigned(From)); 225 Record *Rec = Records.getDef(OS.str()); 226 if (!Rec) 227 PrintFatalError(Loc, "No def named '" + Name + "': " + 228 Expr->getAsString()); 229 // Try to reevaluate Rec in case it is a set. 230 if (const RecVec *Result = ST.expand(Rec)) 231 Elts.insert(Result->begin(), Result->end()); 232 else 233 Elts.insert(Rec); 234 235 From += Step; 236 } 237 } 238 }; 239 240 // Expand a Def into a set by evaluating one of its fields. 241 struct FieldExpander : public SetTheory::Expander { 242 StringRef FieldName; 243 244 FieldExpander(StringRef fn) : FieldName(fn) {} 245 246 void expand(SetTheory &ST, Record *Def, RecSet &Elts) override { 247 ST.evaluate(Def->getValueInit(FieldName), Elts, Def->getLoc()); 248 } 249 }; 250 251 } // end anonymous namespace 252 253 // Pin the vtables to this file. 254 void SetTheory::Operator::anchor() {} 255 void SetTheory::Expander::anchor() {} 256 257 SetTheory::SetTheory() { 258 addOperator("add", std::make_unique<AddOp>()); 259 addOperator("sub", std::make_unique<SubOp>()); 260 addOperator("and", std::make_unique<AndOp>()); 261 addOperator("shl", std::make_unique<ShlOp>()); 262 addOperator("trunc", std::make_unique<TruncOp>()); 263 addOperator("rotl", std::make_unique<RotOp>(false)); 264 addOperator("rotr", std::make_unique<RotOp>(true)); 265 addOperator("decimate", std::make_unique<DecimateOp>()); 266 addOperator("interleave", std::make_unique<InterleaveOp>()); 267 addOperator("sequence", std::make_unique<SequenceOp>()); 268 } 269 270 void SetTheory::addOperator(StringRef Name, std::unique_ptr<Operator> Op) { 271 Operators[Name] = std::move(Op); 272 } 273 274 void SetTheory::addExpander(StringRef ClassName, std::unique_ptr<Expander> E) { 275 Expanders[ClassName] = std::move(E); 276 } 277 278 void SetTheory::addFieldExpander(StringRef ClassName, StringRef FieldName) { 279 addExpander(ClassName, std::make_unique<FieldExpander>(FieldName)); 280 } 281 282 void SetTheory::evaluate(Init *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) { 283 // A def in a list can be a just an element, or it may expand. 284 if (DefInit *Def = dyn_cast<DefInit>(Expr)) { 285 if (const RecVec *Result = expand(Def->getDef())) 286 return Elts.insert(Result->begin(), Result->end()); 287 Elts.insert(Def->getDef()); 288 return; 289 } 290 291 // Lists simply expand. 292 if (ListInit *LI = dyn_cast<ListInit>(Expr)) 293 return evaluate(LI->begin(), LI->end(), Elts, Loc); 294 295 // Anything else must be a DAG. 296 DagInit *DagExpr = dyn_cast<DagInit>(Expr); 297 if (!DagExpr) 298 PrintFatalError(Loc, "Invalid set element: " + Expr->getAsString()); 299 DefInit *OpInit = dyn_cast<DefInit>(DagExpr->getOperator()); 300 if (!OpInit) 301 PrintFatalError(Loc, "Bad set expression: " + Expr->getAsString()); 302 auto I = Operators.find(OpInit->getDef()->getName()); 303 if (I == Operators.end()) 304 PrintFatalError(Loc, "Unknown set operator: " + Expr->getAsString()); 305 I->second->apply(*this, DagExpr, Elts, Loc); 306 } 307 308 const RecVec *SetTheory::expand(Record *Set) { 309 // Check existing entries for Set and return early. 310 ExpandMap::iterator I = Expansions.find(Set); 311 if (I != Expansions.end()) 312 return &I->second; 313 314 // This is the first time we see Set. Find a suitable expander. 315 ArrayRef<std::pair<Record *, SMRange>> SC = Set->getSuperClasses(); 316 for (const auto &SCPair : SC) { 317 // Skip unnamed superclasses. 318 if (!isa<StringInit>(SCPair.first->getNameInit())) 319 continue; 320 auto I = Expanders.find(SCPair.first->getName()); 321 if (I != Expanders.end()) { 322 // This breaks recursive definitions. 323 RecVec &EltVec = Expansions[Set]; 324 RecSet Elts; 325 I->second->expand(*this, Set, Elts); 326 EltVec.assign(Elts.begin(), Elts.end()); 327 return &EltVec; 328 } 329 } 330 331 // Set is not expandable. 332 return nullptr; 333 } 334