DAGISelMatcherEmitter.cpp revision c96087b3433582f1c2bdb4f0ad3dad7f0b350339 
1//===- DAGISelMatcherEmitter.cpp - Matcher Emitter ------------------------===//
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 contains code to generate C++ code a matcher.
11//
12//===----------------------------------------------------------------------===//
13
14#include "DAGISelMatcher.h"
15#include "CodeGenDAGPatterns.h"
16#include "llvm/ADT/DenseMap.h"
17#include "llvm/ADT/SmallString.h"
18#include "llvm/ADT/StringMap.h"
19#include "llvm/Support/FormattedStream.h"
20using namespace llvm;
21
22namespace {
23enum {
24  CommentIndent = 30
25};
26}
27
28/// ClassifyInt - Classify an integer by size, return '1','2','4','8' if this
29/// fits in 1, 2, 4, or 8 sign extended bytes.
30static char ClassifyInt(int64_t Val) {
31  if (Val == int8_t(Val))  return '1';
32  if (Val == int16_t(Val)) return '2';
33  if (Val == int32_t(Val)) return '4';
34  return '8';
35}
36
37/// EmitInt - Emit the specified integer, returning the number of bytes emitted.
38static unsigned EmitInt(int64_t Val, formatted_raw_ostream &OS) {
39  unsigned BytesEmitted = 1;
40  OS << (int)(unsigned char)Val << ", ";
41  if (Val == int8_t(Val)) {
42    OS << "\n";
43    return BytesEmitted;
44  }
45
46  OS << (int)(unsigned char)(Val >> 8) << ", ";
47  ++BytesEmitted;
48
49  if (Val != int16_t(Val)) {
50    OS << (int)(unsigned char)(Val >> 16) << ','
51       << (int)(unsigned char)(Val >> 24) << ',';
52    BytesEmitted += 2;
53
54    if (Val != int32_t(Val)) {
55      OS << (int)(unsigned char)(Val >> 32) << ','
56         << (int)(unsigned char)(Val >> 40) << ','
57         << (int)(unsigned char)(Val >> 48) << ','
58         << (int)(unsigned char)(Val >> 56) << ',';
59      BytesEmitted += 4;
60    }
61  }
62
63  OS.PadToColumn(CommentIndent) << "// " << Val << '\n';
64  return BytesEmitted;
65}
66
67namespace {
68class MatcherTableEmitter {
69  formatted_raw_ostream &OS;
70
71  StringMap<unsigned> NodePredicateMap, PatternPredicateMap;
72  std::vector<std::string> NodePredicates, PatternPredicates;
73
74  DenseMap<const ComplexPattern*, unsigned> ComplexPatternMap;
75  std::vector<const ComplexPattern*> ComplexPatterns;
76public:
77  MatcherTableEmitter(formatted_raw_ostream &os) : OS(os) {}
78
79  unsigned EmitMatcherAndChildren(const MatcherNode *N, unsigned Indent);
80
81  void EmitPredicateFunctions();
82private:
83  unsigned EmitMatcher(const MatcherNode *N, unsigned Indent);
84
85  unsigned getNodePredicate(StringRef PredName) {
86    unsigned &Entry = NodePredicateMap[PredName];
87    if (Entry == 0) {
88      NodePredicates.push_back(PredName.str());
89      Entry = NodePredicates.size();
90    }
91    return Entry-1;
92  }
93  unsigned getPatternPredicate(StringRef PredName) {
94    unsigned &Entry = PatternPredicateMap[PredName];
95    if (Entry == 0) {
96      PatternPredicates.push_back(PredName.str());
97      Entry = PatternPredicates.size();
98    }
99    return Entry-1;
100  }
101
102  unsigned getComplexPat(const ComplexPattern &P) {
103    unsigned &Entry = ComplexPatternMap[&P];
104    if (Entry == 0) {
105      ComplexPatterns.push_back(&P);
106      Entry = ComplexPatterns.size();
107    }
108    return Entry-1;
109  }
110};
111} // end anonymous namespace.
112
113/// EmitMatcherOpcodes - Emit bytes for the specified matcher and return
114/// the number of bytes emitted.
115unsigned MatcherTableEmitter::
116EmitMatcher(const MatcherNode *N, unsigned Indent) {
117  OS.PadToColumn(Indent*2);
118
119  switch (N->getKind()) {
120  case MatcherNode::Push: assert(0 && "Should be handled by caller");
121  case MatcherNode::EmitNode:
122    OS << "// Src: "
123       << *cast<EmitNodeMatcherNode>(N)->getPattern().getSrcPattern() << '\n';
124    OS.PadToColumn(Indent*2) << "// Dst: "
125       << *cast<EmitNodeMatcherNode>(N)->getPattern().getDstPattern() << "\n";
126    OS.PadToColumn(Indent*2) << "OPC_Emit, /*XXX*/\n\n";
127    return 1;
128  case MatcherNode::Record:
129    OS << "OPC_Record,";
130    OS.PadToColumn(CommentIndent) << "// "
131       << cast<RecordMatcherNode>(N)->getWhatFor() << '\n';
132    return 1;
133  case MatcherNode::MoveChild:
134    OS << "OPC_MoveChild, "
135       << cast<MoveChildMatcherNode>(N)->getChildNo() << ",\n";
136    return 2;
137
138  case MatcherNode::MoveParent:
139    OS << "OPC_MoveParent,\n";
140    return 1;
141
142  case MatcherNode::CheckSame:
143    OS << "OPC_CheckSame, "
144       << cast<CheckSameMatcherNode>(N)->getMatchNumber() << ",\n";
145    return 2;
146
147  case MatcherNode::CheckPatternPredicate: {
148    StringRef Pred = cast<CheckPatternPredicateMatcherNode>(N)->getPredicate();
149    OS << "OPC_CheckPatternPredicate, " << getPatternPredicate(Pred) << ',';
150    OS.PadToColumn(CommentIndent) << "// " << Pred << '\n';
151    return 2;
152  }
153  case MatcherNode::CheckPredicate: {
154    StringRef Pred = cast<CheckPredicateMatcherNode>(N)->getPredicateName();
155    OS << "OPC_CheckPredicate, " << getNodePredicate(Pred) << ',';
156    OS.PadToColumn(CommentIndent) << "// " << Pred << '\n';
157    return 2;
158  }
159
160  case MatcherNode::CheckOpcode:
161    OS << "OPC_CheckOpcode, "
162       << cast<CheckOpcodeMatcherNode>(N)->getOpcodeName() << ",\n";
163    return 2;
164
165  case MatcherNode::CheckType:
166    OS << "OPC_CheckType, "
167       << getEnumName(cast<CheckTypeMatcherNode>(N)->getType()) << ",\n";
168    return 2;
169
170  case MatcherNode::CheckInteger: {
171    int64_t Val = cast<CheckIntegerMatcherNode>(N)->getValue();
172    OS << "OPC_CheckInteger" << ClassifyInt(Val) << ", ";
173    return EmitInt(Val, OS)+1;
174  }
175  case MatcherNode::CheckCondCode:
176    OS << "OPC_CheckCondCode, ISD::"
177       << cast<CheckCondCodeMatcherNode>(N)->getCondCodeName() << ",\n";
178    return 2;
179
180  case MatcherNode::CheckValueType:
181    OS << "OPC_CheckValueType, MVT::"
182       << cast<CheckValueTypeMatcherNode>(N)->getTypeName() << ",\n";
183    return 2;
184
185  case MatcherNode::CheckComplexPat: {
186    const ComplexPattern &Pattern =
187      cast<CheckComplexPatMatcherNode>(N)->getPattern();
188    OS << "OPC_CheckComplexPat, " << getComplexPat(Pattern) << ',';
189    OS.PadToColumn(CommentIndent) << "// " << Pattern.getSelectFunc() << '\n';
190    return 2;
191  }
192
193  case MatcherNode::CheckAndImm: {
194    int64_t Val = cast<CheckAndImmMatcherNode>(N)->getValue();
195    OS << "OPC_CheckAndImm" << ClassifyInt(Val) << ", ";
196    return EmitInt(Val, OS)+1;
197  }
198
199  case MatcherNode::CheckOrImm: {
200    int64_t Val = cast<CheckOrImmMatcherNode>(N)->getValue();
201    OS << "OPC_CheckOrImm" << ClassifyInt(Val) << ", ";
202    return EmitInt(Val, OS)+1;
203  }
204  case MatcherNode::CheckFoldableChainNode:
205    OS << "OPC_CheckFoldableChainNode,\n";
206    return 1;
207  }
208  assert(0 && "Unreachable");
209  return 0;
210}
211
212/// EmitMatcherAndChildren - Emit the bytes for the specified matcher subtree.
213unsigned MatcherTableEmitter::
214EmitMatcherAndChildren(const MatcherNode *N, unsigned Indent) {
215  unsigned Size = 0;
216  while (1) {
217    // Push is a special case since it is binary.
218    if (const PushMatcherNode *PMN = dyn_cast<PushMatcherNode>(N)) {
219      // We need to encode the child and the offset of the failure code before
220      // emitting either of them.  Handle this by buffering the output into a
221      // string while we get the size.
222      SmallString<128> TmpBuf;
223      unsigned ChildSize;
224      {
225        raw_svector_ostream OS(TmpBuf);
226        formatted_raw_ostream FOS(OS);
227        ChildSize =
228          EmitMatcherAndChildren(cast<PushMatcherNode>(N)->getChild(),Indent+1);
229      }
230
231      if (ChildSize > 255) {
232        errs() <<
233          "Tblgen internal error: can't handle predicate this complex yet\n";
234        exit(1);
235      }
236
237      OS.PadToColumn(Indent*2);
238      OS << "OPC_Push, " << ChildSize << ",\n";
239      OS << TmpBuf.str();
240
241      Size += 2 + ChildSize;
242
243      N = PMN->getFailure();
244      continue;
245    }
246
247    Size += EmitMatcher(N, Indent);
248
249    // If there are children of this node, iterate to them, otherwise we're
250    // done.
251    if (const MatcherNodeWithChild *MNWC = dyn_cast<MatcherNodeWithChild>(N))
252      N = MNWC->getChild();
253    else
254      return Size;
255  }
256}
257
258void MatcherTableEmitter::EmitPredicateFunctions() {
259  // Emit pattern predicates.
260  OS << "bool CheckPatternPredicate(unsigned PredNo) const {\n";
261  OS << "  switch (PredNo) {\n";
262  OS << "  default: assert(0 && \"Invalid predicate in table?\");\n";
263  for (unsigned i = 0, e = PatternPredicates.size(); i != e; ++i)
264    OS << "  case " << i << ": return "  << PatternPredicates[i] << ";\n";
265  OS << "  }\n";
266  OS << "}\n\n";
267
268  // Emit Node predicates.
269  OS << "bool CheckNodePredicate(SDNode *N, unsigned PredNo) const {\n";
270  OS << "  switch (PredNo) {\n";
271  OS << "  default: assert(0 && \"Invalid predicate in table?\");\n";
272  for (unsigned i = 0, e = NodePredicates.size(); i != e; ++i)
273    OS << "  case " << i << ": return "  << NodePredicates[i] << "(N);\n";
274  OS << "  }\n";
275  OS << "}\n\n";
276
277  // Emit CompletePattern matchers.
278  OS << "bool CheckComplexPattern(SDNode *Root, SDValue N,\n";
279  OS << "      unsigned PatternNo, SmallVectorImpl<SDValue> &Result) {\n";
280  OS << "  switch (PatternNo) {\n";
281  OS << "  default: assert(0 && \"Invalid pattern # in table?\");\n";
282  for (unsigned i = 0, e = ComplexPatterns.size(); i != e; ++i) {
283    const ComplexPattern &P = *ComplexPatterns[i];
284    unsigned NumOps = P.getNumOperands();
285    if (P.hasProperty(SDNPHasChain))
286      NumOps += 2; // Input and output chains.
287    OS << "  case " << i << ":\n";
288    OS << "    Result.resize(Result.size()+" << NumOps << ");\n";
289    OS << "    return "  << P.getSelectFunc() << "(Root, N";
290    for (unsigned i = 0; i != NumOps; ++i)
291      OS << ", Result[Result.size()-" << (NumOps-i) << ']';
292    OS << ");\n";
293  }
294  OS << "  }\n";
295  OS << "}\n\n";
296}
297
298
299void llvm::EmitMatcherTable(const MatcherNode *Matcher, raw_ostream &O) {
300  formatted_raw_ostream OS(O);
301
302  OS << "// The main instruction selector code.\n";
303  OS << "SDNode *SelectCode2(SDNode *N) {\n";
304
305  MatcherTableEmitter MatcherEmitter(OS);
306
307  OS << "  static const unsigned char MatcherTable[] = {\n";
308  unsigned TotalSize = MatcherEmitter.EmitMatcherAndChildren(Matcher, 2);
309  OS << "    0\n  }; // Total Array size is " << (TotalSize+1) << " bytes\n\n";
310  OS << "  return SelectCodeCommon(N, MatcherTable,sizeof(MatcherTable));\n}\n";
311  OS << "\n";
312
313  // Next up, emit the function for node and pattern predicates:
314  MatcherEmitter.EmitPredicateFunctions();
315}
316