SetTheory.cpp revision 2c6d71388fb1b68ce6fdbb88642a95a24b27b2a7 
1//===- SetTheory.cpp - Generate ordered sets from DAG expressions ---------===//
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 implements the SetTheory class that computes ordered sets of
11// Records from DAG expressions.
12//
13//===----------------------------------------------------------------------===//
14
15#include "SetTheory.h"
16#include "llvm/TableGen/Error.h"
17#include "llvm/TableGen/Record.h"
18#include "llvm/Support/Format.h"
19
20using namespace llvm;
21
22// Define the standard operators.
23namespace {
24
25typedef SetTheory::RecSet RecSet;
26typedef SetTheory::RecVec RecVec;
27
28// (add a, b, ...) Evaluate and union all arguments.
29struct AddOp : public SetTheory::Operator {
30  void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
31    ST.evaluate(Expr->arg_begin(), Expr->arg_end(), Elts, Loc);
32  }
33};
34
35// (sub Add, Sub, ...) Set difference.
36struct SubOp : public SetTheory::Operator {
37  void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
38    if (Expr->arg_size() < 2)
39      throw TGError(Loc, "Set difference needs at least two arguments: " +
40        Expr->getAsString());
41    RecSet Add, Sub;
42    ST.evaluate(*Expr->arg_begin(), Add, Loc);
43    ST.evaluate(Expr->arg_begin() + 1, Expr->arg_end(), Sub, Loc);
44    for (RecSet::iterator I = Add.begin(), E = Add.end(); I != E; ++I)
45      if (!Sub.count(*I))
46        Elts.insert(*I);
47  }
48};
49
50// (and S1, S2) Set intersection.
51struct AndOp : public SetTheory::Operator {
52  void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
53    if (Expr->arg_size() != 2)
54      throw TGError(Loc, "Set intersection requires two arguments: " +
55        Expr->getAsString());
56    RecSet S1, S2;
57    ST.evaluate(Expr->arg_begin()[0], S1, Loc);
58    ST.evaluate(Expr->arg_begin()[1], S2, Loc);
59    for (RecSet::iterator I = S1.begin(), E = S1.end(); I != E; ++I)
60      if (S2.count(*I))
61        Elts.insert(*I);
62  }
63};
64
65// SetIntBinOp - Abstract base class for (Op S, N) operators.
66struct SetIntBinOp : public SetTheory::Operator {
67  virtual void apply2(SetTheory &ST, DagInit *Expr,
68                     RecSet &Set, int64_t N,
69                     RecSet &Elts, ArrayRef<SMLoc> Loc) =0;
70
71  void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
72    if (Expr->arg_size() != 2)
73      throw TGError(Loc, "Operator requires (Op Set, Int) arguments: " +
74        Expr->getAsString());
75    RecSet Set;
76    ST.evaluate(Expr->arg_begin()[0], Set, Loc);
77    IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[1]);
78    if (!II)
79      throw TGError(Loc, "Second argument must be an integer: " +
80        Expr->getAsString());
81    apply2(ST, Expr, Set, II->getValue(), Elts, Loc);
82  }
83};
84
85// (shl S, N) Shift left, remove the first N elements.
86struct ShlOp : public SetIntBinOp {
87  void apply2(SetTheory &ST, DagInit *Expr,
88             RecSet &Set, int64_t N,
89             RecSet &Elts, ArrayRef<SMLoc> Loc) {
90    if (N < 0)
91      throw TGError(Loc, "Positive shift required: " +
92        Expr->getAsString());
93    if (unsigned(N) < Set.size())
94      Elts.insert(Set.begin() + N, Set.end());
95  }
96};
97
98// (trunc S, N) Truncate after the first N elements.
99struct TruncOp : public SetIntBinOp {
100  void apply2(SetTheory &ST, DagInit *Expr,
101             RecSet &Set, int64_t N,
102             RecSet &Elts, ArrayRef<SMLoc> Loc) {
103    if (N < 0)
104      throw TGError(Loc, "Positive length required: " +
105        Expr->getAsString());
106    if (unsigned(N) > Set.size())
107      N = Set.size();
108    Elts.insert(Set.begin(), Set.begin() + N);
109  }
110};
111
112// Left/right rotation.
113struct RotOp : public SetIntBinOp {
114  const bool Reverse;
115
116  RotOp(bool Rev) : Reverse(Rev) {}
117
118  void apply2(SetTheory &ST, DagInit *Expr,
119             RecSet &Set, int64_t N,
120             RecSet &Elts, ArrayRef<SMLoc> Loc) {
121    if (Reverse)
122      N = -N;
123    // N > 0 -> rotate left, N < 0 -> rotate right.
124    if (Set.empty())
125      return;
126    if (N < 0)
127      N = Set.size() - (-N % Set.size());
128    else
129      N %= Set.size();
130    Elts.insert(Set.begin() + N, Set.end());
131    Elts.insert(Set.begin(), Set.begin() + N);
132  }
133};
134
135// (decimate S, N) Pick every N'th element of S.
136struct DecimateOp : public SetIntBinOp {
137  void apply2(SetTheory &ST, DagInit *Expr,
138             RecSet &Set, int64_t N,
139             RecSet &Elts, ArrayRef<SMLoc> Loc) {
140    if (N <= 0)
141      throw TGError(Loc, "Positive stride required: " +
142        Expr->getAsString());
143    for (unsigned I = 0; I < Set.size(); I += N)
144      Elts.insert(Set[I]);
145  }
146};
147
148// (interleave S1, S2, ...) Interleave elements of the arguments.
149struct InterleaveOp : public SetTheory::Operator {
150  void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
151    // Evaluate the arguments individually.
152    SmallVector<RecSet, 4> Args(Expr->getNumArgs());
153    unsigned MaxSize = 0;
154    for (unsigned i = 0, e = Expr->getNumArgs(); i != e; ++i) {
155      ST.evaluate(Expr->getArg(i), Args[i], Loc);
156      MaxSize = std::max(MaxSize, unsigned(Args[i].size()));
157    }
158    // Interleave arguments into Elts.
159    for (unsigned n = 0; n != MaxSize; ++n)
160      for (unsigned i = 0, e = Expr->getNumArgs(); i != e; ++i)
161        if (n < Args[i].size())
162          Elts.insert(Args[i][n]);
163  }
164};
165
166// (sequence "Format", From, To) Generate a sequence of records by name.
167struct SequenceOp : public SetTheory::Operator {
168  void apply(SetTheory &ST, DagInit *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
169    int Step = 1;
170    if (Expr->arg_size() > 4)
171      throw TGError(Loc, "Bad args to (sequence \"Format\", From, To): " +
172        Expr->getAsString());
173    else if (Expr->arg_size() == 4) {
174      if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[3])) {
175        Step = II->getValue();
176      } else
177        throw TGError(Loc, "Stride must be an integer: " + Expr->getAsString());
178    }
179
180    std::string Format;
181    if (StringInit *SI = dyn_cast<StringInit>(Expr->arg_begin()[0]))
182      Format = SI->getValue();
183    else
184      throw TGError(Loc,  "Format must be a string: " + Expr->getAsString());
185
186    int64_t From, To;
187    if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[1]))
188      From = II->getValue();
189    else
190      throw TGError(Loc, "From must be an integer: " + Expr->getAsString());
191    if (From < 0 || From >= (1 << 30))
192      throw TGError(Loc, "From out of range");
193
194    if (IntInit *II = dyn_cast<IntInit>(Expr->arg_begin()[2]))
195      To = II->getValue();
196    else
197      throw TGError(Loc, "From must be an integer: " + Expr->getAsString());
198    if (To < 0 || To >= (1 << 30))
199      throw TGError(Loc, "To out of range");
200
201    RecordKeeper &Records =
202      cast<DefInit>(Expr->getOperator())->getDef()->getRecords();
203
204    Step *= From <= To ? 1 : -1;
205    while (true) {
206      if (Step > 0 && From > To)
207        break;
208      else if (Step < 0 && From < To)
209        break;
210      std::string Name;
211      raw_string_ostream OS(Name);
212      OS << format(Format.c_str(), unsigned(From));
213      Record *Rec = Records.getDef(OS.str());
214      if (!Rec)
215        throw TGError(Loc, "No def named '" + Name + "': " +
216          Expr->getAsString());
217      // Try to reevaluate Rec in case it is a set.
218      if (const RecVec *Result = ST.expand(Rec))
219        Elts.insert(Result->begin(), Result->end());
220      else
221        Elts.insert(Rec);
222
223      From += Step;
224    }
225  }
226};
227
228// Expand a Def into a set by evaluating one of its fields.
229struct FieldExpander : public SetTheory::Expander {
230  StringRef FieldName;
231
232  FieldExpander(StringRef fn) : FieldName(fn) {}
233
234  void expand(SetTheory &ST, Record *Def, RecSet &Elts) {
235    ST.evaluate(Def->getValueInit(FieldName), Elts, Def->getLoc());
236  }
237};
238} // end anonymous namespace
239
240void SetTheory::Operator::anchor() { }
241
242void SetTheory::Expander::anchor() { }
243
244SetTheory::SetTheory() {
245  addOperator("add", new AddOp);
246  addOperator("sub", new SubOp);
247  addOperator("and", new AndOp);
248  addOperator("shl", new ShlOp);
249  addOperator("trunc", new TruncOp);
250  addOperator("rotl", new RotOp(false));
251  addOperator("rotr", new RotOp(true));
252  addOperator("decimate", new DecimateOp);
253  addOperator("interleave", new InterleaveOp);
254  addOperator("sequence", new SequenceOp);
255}
256
257void SetTheory::addOperator(StringRef Name, Operator *Op) {
258  Operators[Name] = Op;
259}
260
261void SetTheory::addExpander(StringRef ClassName, Expander *E) {
262  Expanders[ClassName] = E;
263}
264
265void SetTheory::addFieldExpander(StringRef ClassName, StringRef FieldName) {
266  addExpander(ClassName, new FieldExpander(FieldName));
267}
268
269void SetTheory::evaluate(Init *Expr, RecSet &Elts, ArrayRef<SMLoc> Loc) {
270  // A def in a list can be a just an element, or it may expand.
271  if (DefInit *Def = dyn_cast<DefInit>(Expr)) {
272    if (const RecVec *Result = expand(Def->getDef()))
273      return Elts.insert(Result->begin(), Result->end());
274    Elts.insert(Def->getDef());
275    return;
276  }
277
278  // Lists simply expand.
279  if (ListInit *LI = dyn_cast<ListInit>(Expr))
280    return evaluate(LI->begin(), LI->end(), Elts, Loc);
281
282  // Anything else must be a DAG.
283  DagInit *DagExpr = dyn_cast<DagInit>(Expr);
284  if (!DagExpr)
285    throw TGError(Loc, "Invalid set element: " + Expr->getAsString());
286  DefInit *OpInit = dyn_cast<DefInit>(DagExpr->getOperator());
287  if (!OpInit)
288    throw TGError(Loc, "Bad set expression: " + Expr->getAsString());
289  Operator *Op = Operators.lookup(OpInit->getDef()->getName());
290  if (!Op)
291    throw TGError(Loc, "Unknown set operator: " + Expr->getAsString());
292  Op->apply(*this, DagExpr, Elts, Loc);
293}
294
295const RecVec *SetTheory::expand(Record *Set) {
296  // Check existing entries for Set and return early.
297  ExpandMap::iterator I = Expansions.find(Set);
298  if (I != Expansions.end())
299    return &I->second;
300
301  // This is the first time we see Set. Find a suitable expander.
302  const std::vector<Record*> &SC = Set->getSuperClasses();
303  for (unsigned i = 0, e = SC.size(); i != e; ++i) {
304    // Skip unnamed superclasses.
305    if (!dyn_cast<StringInit>(SC[i]->getNameInit()))
306      continue;
307    if (Expander *Exp = Expanders.lookup(SC[i]->getName())) {
308      // This breaks recursive definitions.
309      RecVec &EltVec = Expansions[Set];
310      RecSet Elts;
311      Exp->expand(*this, Set, Elts);
312      EltVec.assign(Elts.begin(), Elts.end());
313      return &EltVec;
314    }
315  }
316
317  // Set is not expandable.
318  return 0;
319}
320
321