1 //=== ClangOpcodesEmitter.cpp - constexpr interpreter opcodes ---*- C++ -*-===//
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 // These tablegen backends emit Clang AST node tables
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "TableGenBackends.h"
14 #include "llvm/TableGen/Error.h"
15 #include "llvm/TableGen/Record.h"
16 #include "llvm/TableGen/StringMatcher.h"
17 #include "llvm/TableGen/TableGenBackend.h"
18 
19 using namespace llvm;
20 
21 namespace {
22 class ClangOpcodesEmitter {
23   RecordKeeper &Records;
24   Record Root;
25   unsigned NumTypes;
26 
27 public:
28   ClangOpcodesEmitter(RecordKeeper &R)
29     : Records(R), Root("Opcode", SMLoc(), R),
30       NumTypes(Records.getAllDerivedDefinitions("Type").size()) {}
31 
32   void run(raw_ostream &OS);
33 
34 private:
35   /// Emits the opcode name for the opcode enum.
36   /// The name is obtained by concatenating the name with the list of types.
37   void EmitEnum(raw_ostream &OS, StringRef N, Record *R);
38 
39   /// Emits the switch case and the invocation in the interpreter.
40   void EmitInterp(raw_ostream &OS, StringRef N, Record *R);
41 
42   /// Emits the disassembler.
43   void EmitDisasm(raw_ostream &OS, StringRef N, Record *R);
44 
45   /// Emits the byte code emitter method.
46   void EmitEmitter(raw_ostream &OS, StringRef N, Record *R);
47 
48   /// Emits the prototype.
49   void EmitProto(raw_ostream &OS, StringRef N, Record *R);
50 
51   /// Emits the prototype to dispatch from a type.
52   void EmitGroup(raw_ostream &OS, StringRef N, Record *R);
53 
54   /// Emits the evaluator method.
55   void EmitEval(raw_ostream &OS, StringRef N, Record *R);
56 
57   void PrintTypes(raw_ostream &OS, ArrayRef<Record *> Types);
58 };
59 
60 void Enumerate(const Record *R,
61                StringRef N,
62                std::function<void(ArrayRef<Record *>, Twine)> &&F) {
63   llvm::SmallVector<Record *, 2> TypePath;
64   auto *Types = R->getValueAsListInit("Types");
65 
66   std::function<void(size_t, const Twine &)> Rec;
67   Rec = [&TypePath, Types, &Rec, &F](size_t I, const Twine &ID) {
68     if (I >= Types->size()) {
69       F(TypePath, ID);
70       return;
71     }
72 
73     if (auto *TypeClass = dyn_cast<DefInit>(Types->getElement(I))) {
74       for (auto *Type : TypeClass->getDef()->getValueAsListOfDefs("Types")) {
75         TypePath.push_back(Type);
76         Rec(I + 1, ID + Type->getName());
77         TypePath.pop_back();
78       }
79     } else {
80       PrintFatalError("Expected a type class");
81     }
82   };
83   Rec(0, N);
84 }
85 
86 } // namespace
87 
88 void ClangOpcodesEmitter::run(raw_ostream &OS) {
89   for (auto *Opcode : Records.getAllDerivedDefinitions(Root.getName())) {
90     // The name is the record name, unless overriden.
91     StringRef N = Opcode->getValueAsString("Name");
92     if (N.empty())
93       N = Opcode->getName();
94 
95     EmitEnum(OS, N, Opcode);
96     EmitInterp(OS, N, Opcode);
97     EmitDisasm(OS, N, Opcode);
98     EmitProto(OS, N, Opcode);
99     EmitGroup(OS, N, Opcode);
100     EmitEmitter(OS, N, Opcode);
101     EmitEval(OS, N, Opcode);
102   }
103 }
104 
105 void ClangOpcodesEmitter::EmitEnum(raw_ostream &OS, StringRef N, Record *R) {
106   OS << "#ifdef GET_OPCODE_NAMES\n";
107   Enumerate(R, N, [&OS](ArrayRef<Record *>, const Twine &ID) {
108     OS << "OP_" << ID << ",\n";
109   });
110   OS << "#endif\n";
111 }
112 
113 void ClangOpcodesEmitter::EmitInterp(raw_ostream &OS, StringRef N, Record *R) {
114   OS << "#ifdef GET_INTERP\n";
115 
116   Enumerate(R, N, [this, R, &OS, &N](ArrayRef<Record *> TS, const Twine &ID) {
117     bool CanReturn = R->getValueAsBit("CanReturn");
118     bool ChangesPC = R->getValueAsBit("ChangesPC");
119     auto Args = R->getValueAsListOfDefs("Args");
120 
121     OS << "case OP_" << ID << ": {\n";
122 
123     // Emit calls to read arguments.
124     for (size_t I = 0, N = Args.size(); I < N; ++I) {
125       OS << "  auto V" << I;
126       OS << " = ";
127       OS << "ReadArg<" << Args[I]->getValueAsString("Name") << ">(S, PC);\n";
128     }
129 
130     // Emit a call to the template method and pass arguments.
131     OS << "  if (!" << N;
132     PrintTypes(OS, TS);
133     OS << "(S";
134     if (ChangesPC)
135       OS << ", PC";
136     else
137       OS << ", OpPC";
138     if (CanReturn)
139       OS << ", Result";
140     for (size_t I = 0, N = Args.size(); I < N; ++I)
141       OS << ", V" << I;
142     OS << "))\n";
143     OS << "    return false;\n";
144 
145     // Bail out if interpreter returned.
146     if (CanReturn) {
147       OS << "  if (!S.Current || S.Current->isRoot())\n";
148       OS << "    return true;\n";
149     }
150 
151     OS << "  continue;\n";
152     OS << "}\n";
153   });
154   OS << "#endif\n";
155 }
156 
157 void ClangOpcodesEmitter::EmitDisasm(raw_ostream &OS, StringRef N, Record *R) {
158   OS << "#ifdef GET_DISASM\n";
159   Enumerate(R, N, [R, &OS](ArrayRef<Record *>, const Twine &ID) {
160     OS << "case OP_" << ID << ":\n";
161     OS << "  PrintName(\"" << ID << "\");\n";
162     OS << "  OS << \"\\t\"";
163 
164     for (auto *Arg : R->getValueAsListOfDefs("Args")) {
165       OS << " << ReadArg<" << Arg->getValueAsString("Name") << ">(P, PC)";
166       OS << " << \" \"";
167     }
168 
169     OS << " << \"\\n\";\n";
170     OS << "  continue;\n";
171   });
172   OS << "#endif\n";
173 }
174 
175 void ClangOpcodesEmitter::EmitEmitter(raw_ostream &OS, StringRef N, Record *R) {
176   if (R->getValueAsBit("HasCustomLink"))
177     return;
178 
179   OS << "#ifdef GET_LINK_IMPL\n";
180   Enumerate(R, N, [R, &OS](ArrayRef<Record *>, const Twine &ID) {
181     auto Args = R->getValueAsListOfDefs("Args");
182 
183     // Emit the list of arguments.
184     OS << "bool ByteCodeEmitter::emit" << ID << "(";
185     for (size_t I = 0, N = Args.size(); I < N; ++I)
186       OS << Args[I]->getValueAsString("Name") << " A" << I << ", ";
187     OS << "const SourceInfo &L) {\n";
188 
189     // Emit a call to write the opcodes.
190     OS << "  return emitOp<";
191     for (size_t I = 0, N = Args.size(); I < N; ++I) {
192       if (I != 0)
193         OS << ", ";
194       OS << Args[I]->getValueAsString("Name");
195     }
196     OS << ">(OP_" << ID;
197     for (size_t I = 0, N = Args.size(); I < N; ++I)
198       OS << ", A" << I;
199     OS << ", L);\n";
200     OS << "}\n";
201   });
202   OS << "#endif\n";
203 }
204 
205 void ClangOpcodesEmitter::EmitProto(raw_ostream &OS, StringRef N, Record *R) {
206   OS << "#if defined(GET_EVAL_PROTO) || defined(GET_LINK_PROTO)\n";
207   auto Args = R->getValueAsListOfDefs("Args");
208   Enumerate(R, N, [&OS, &Args](ArrayRef<Record *> TS, const Twine &ID) {
209     OS << "bool emit" << ID << "(";
210     for (auto *Arg : Args)
211       OS << Arg->getValueAsString("Name") << ", ";
212     OS << "const SourceInfo &);\n";
213   });
214 
215   // Emit a template method for custom emitters to have less to implement.
216   auto TypeCount = R->getValueAsListInit("Types")->size();
217   if (R->getValueAsBit("HasCustomEval") && TypeCount) {
218     OS << "#if defined(GET_EVAL_PROTO)\n";
219     OS << "template<";
220     for (size_t I = 0; I < TypeCount; ++I) {
221       if (I != 0)
222         OS << ", ";
223       OS << "PrimType";
224     }
225     OS << ">\n";
226     OS << "bool emit" << N << "(";
227     for (auto *Arg : Args)
228       OS << Arg->getValueAsString("Name") << ", ";
229     OS << "const SourceInfo &);\n";
230     OS << "#endif\n";
231   }
232 
233   OS << "#endif\n";
234 }
235 
236 void ClangOpcodesEmitter::EmitGroup(raw_ostream &OS, StringRef N, Record *R) {
237   if (!R->getValueAsBit("HasGroup"))
238     return;
239 
240   auto *Types = R->getValueAsListInit("Types");
241   auto Args = R->getValueAsListOfDefs("Args");
242 
243   // Emit the prototype of the group emitter in the header.
244   OS << "#if defined(GET_EVAL_PROTO) || defined(GET_LINK_PROTO)\n";
245   OS << "bool emit" << N << "(";
246   for (size_t I = 0, N = Types->size(); I < N; ++I)
247     OS << "PrimType, ";
248   for (auto *Arg : Args)
249     OS << Arg->getValueAsString("Name") << ", ";
250   OS << "const SourceInfo &I);\n";
251   OS << "#endif\n";
252 
253   // Emit the dispatch implementation in the source.
254   OS << "#if defined(GET_EVAL_IMPL) || defined(GET_LINK_IMPL)\n";
255   OS << "bool\n";
256   OS << "#if defined(GET_EVAL_IMPL)\n";
257   OS << "EvalEmitter\n";
258   OS << "#else\n";
259   OS << "ByteCodeEmitter\n";
260   OS << "#endif\n";
261   OS << "::emit" << N << "(";
262   for (size_t I = 0, N = Types->size(); I < N; ++I)
263     OS << "PrimType T" << I << ", ";
264   for (size_t I = 0, N = Args.size(); I < N; ++I)
265     OS << Args[I]->getValueAsString("Name") << " A" << I << ", ";
266   OS << "const SourceInfo &I) {\n";
267 
268   std::function<void(size_t, const Twine &)> Rec;
269   llvm::SmallVector<Record *, 2> TS;
270   Rec = [this, &Rec, &OS, Types, &Args, R, &TS, N](size_t I, const Twine &ID) {
271     if (I >= Types->size()) {
272       // Print a call to the emitter method.
273       // Custom evaluator methods dispatch to template methods.
274       if (R->getValueAsBit("HasCustomEval")) {
275         OS << "#ifdef GET_LINK_IMPL\n";
276         OS << "    return emit" << ID << "\n";
277         OS << "#else\n";
278         OS << "    return emit" << N;
279         PrintTypes(OS, TS);
280         OS << "\n#endif\n";
281         OS << "      ";
282       } else {
283         OS << "    return emit" << ID;
284       }
285 
286       OS << "(";
287       for (size_t I = 0; I < Args.size(); ++I) {
288         OS << "A" << I << ", ";
289       }
290       OS << "I);\n";
291       return;
292     }
293 
294     // Print a switch statement selecting T.
295     if (auto *TypeClass = dyn_cast<DefInit>(Types->getElement(I))) {
296       OS << "  switch (T" << I << ") {\n";
297       auto Cases = TypeClass->getDef()->getValueAsListOfDefs("Types");
298       for (auto *Case : Cases) {
299         OS << "  case PT_" << Case->getName() << ":\n";
300         TS.push_back(Case);
301         Rec(I + 1, ID + Case->getName());
302         TS.pop_back();
303       }
304       // Emit a default case if not all types are present.
305       if (Cases.size() < NumTypes)
306         OS << "  default: llvm_unreachable(\"invalid type\");\n";
307       OS << "  }\n";
308       OS << "  llvm_unreachable(\"invalid enum value\");\n";
309     } else {
310       PrintFatalError("Expected a type class");
311     }
312   };
313   Rec(0, N);
314 
315   OS << "}\n";
316   OS << "#endif\n";
317 }
318 
319 void ClangOpcodesEmitter::EmitEval(raw_ostream &OS, StringRef N, Record *R) {
320   if (R->getValueAsBit("HasCustomEval"))
321     return;
322 
323   OS << "#ifdef GET_EVAL_IMPL\n";
324   Enumerate(R, N, [this, R, &N, &OS](ArrayRef<Record *> TS, const Twine &ID) {
325     auto Args = R->getValueAsListOfDefs("Args");
326 
327     OS << "bool EvalEmitter::emit" << ID << "(";
328     for (size_t I = 0, N = Args.size(); I < N; ++I)
329       OS << Args[I]->getValueAsString("Name") << " A" << I << ", ";
330     OS << "const SourceInfo &L) {\n";
331     OS << "  if (!isActive()) return true;\n";
332     OS << "  CurrentSource = L;\n";
333 
334     OS << "  return " << N;
335     PrintTypes(OS, TS);
336     OS << "(S, OpPC";
337     for (size_t I = 0, N = Args.size(); I < N; ++I)
338       OS << ", A" << I;
339     OS << ");\n";
340     OS << "}\n";
341   });
342 
343   OS << "#endif\n";
344 }
345 
346 void ClangOpcodesEmitter::PrintTypes(raw_ostream &OS, ArrayRef<Record *> Types) {
347   if (Types.empty())
348     return;
349   OS << "<";
350   for (size_t I = 0, N = Types.size(); I < N; ++I) {
351     if (I != 0)
352       OS << ", ";
353     OS << "PT_" << Types[I]->getName();
354   }
355   OS << ">";
356 }
357 
358 void clang::EmitClangOpcodes(RecordKeeper &Records, raw_ostream &OS) {
359   ClangOpcodesEmitter(Records).run(OS);
360 }
361