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 << "\tauto V" << I;
126       OS << " = ";
127       OS << "PC.read<" << Args[I]->getValueAsString("Name") << ">();\n";
128     }
129 
130     // Emit a call to the template method and pass arguments.
131     OS << "\tif (!" << 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 << "\t\treturn false;\n";
144 
145     // Bail out if interpreter returned.
146     if (CanReturn) {
147       OS << "\tif (!S.Current || S.Current->isRoot())\n";
148       OS << "\t\treturn true;\n";
149     }
150 
151     OS << "\tcontinue;\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 << "\tPrintName(\"" << ID << "\");\n";
162     OS << "\tOS << \"\\t\"";
163 
164     for (auto *Arg : R->getValueAsListOfDefs("Args"))
165       OS << " << PC.read<" << Arg->getValueAsString("Name") << ">() << \" \"";
166 
167     OS << "<< \"\\n\";\n";
168     OS << "\tcontinue;\n";
169   });
170   OS << "#endif\n";
171 }
172 
173 void ClangOpcodesEmitter::EmitEmitter(raw_ostream &OS, StringRef N, Record *R) {
174   if (R->getValueAsBit("HasCustomLink"))
175     return;
176 
177   OS << "#ifdef GET_LINK_IMPL\n";
178   Enumerate(R, N, [R, &OS](ArrayRef<Record *>, const Twine &ID) {
179     auto Args = R->getValueAsListOfDefs("Args");
180 
181     // Emit the list of arguments.
182     OS << "bool ByteCodeEmitter::emit" << ID << "(";
183     for (size_t I = 0, N = Args.size(); I < N; ++I)
184       OS << Args[I]->getValueAsString("Name") << " A" << I << ",";
185     OS << "const SourceInfo &L) {\n";
186 
187     // Emit a call to write the opcodes.
188     OS << "\treturn emitOp<";
189     for (size_t I = 0, N = Args.size(); I < N; ++I) {
190       if (I != 0)
191         OS << ", ";
192       OS << Args[I]->getValueAsString("Name");
193     }
194     OS << ">(OP_" << ID;
195     for (size_t I = 0, N = Args.size(); I < N; ++I)
196       OS << ", A" << I;
197     OS << ", L);\n";
198     OS << "}\n";
199   });
200   OS << "#endif\n";
201 }
202 
203 void ClangOpcodesEmitter::EmitProto(raw_ostream &OS, StringRef N, Record *R) {
204   OS << "#if defined(GET_EVAL_PROTO) || defined(GET_LINK_PROTO)\n";
205   auto Args = R->getValueAsListOfDefs("Args");
206   Enumerate(R, N, [&OS, &Args](ArrayRef<Record *> TS, const Twine &ID) {
207     OS << "bool emit" << ID << "(";
208     for (auto *Arg : Args)
209       OS << Arg->getValueAsString("Name") << ", ";
210     OS << "const SourceInfo &);\n";
211   });
212 
213   // Emit a template method for custom emitters to have less to implement.
214   auto TypeCount = R->getValueAsListInit("Types")->size();
215   if (R->getValueAsBit("HasCustomEval") && TypeCount) {
216     OS << "#if defined(GET_EVAL_PROTO)\n";
217     OS << "template<";
218     for (size_t I = 0; I < TypeCount; ++I) {
219       if (I != 0)
220         OS << ", ";
221       OS << "PrimType";
222     }
223     OS << ">\n";
224     OS << "bool emit" << N << "(";
225     for (auto *Arg : Args)
226       OS << Arg->getValueAsString("Name") << ", ";
227     OS << "const SourceInfo &);\n";
228     OS << "#endif\n";
229   }
230 
231   OS << "#endif\n";
232 }
233 
234 void ClangOpcodesEmitter::EmitGroup(raw_ostream &OS, StringRef N, Record *R) {
235   if (!R->getValueAsBit("HasGroup"))
236     return;
237 
238   auto *Types = R->getValueAsListInit("Types");
239   auto Args = R->getValueAsListOfDefs("Args");
240 
241   // Emit the prototype of the group emitter in the header.
242   OS << "#if defined(GET_EVAL_PROTO) || defined(GET_LINK_PROTO)\n";
243   OS << "bool emit" << N << "(";
244   for (size_t I = 0, N = Types->size(); I < N; ++I)
245     OS << "PrimType, ";
246   for (auto *Arg : Args)
247     OS << Arg->getValueAsString("Name") << ", ";
248   OS << "const SourceInfo &I);\n";
249   OS << "#endif\n";
250 
251   // Emit the dispatch implementation in the source.
252   OS << "#if defined(GET_EVAL_IMPL) || defined(GET_LINK_IMPL)\n";
253   OS << "bool \n";
254   OS << "#if defined(GET_EVAL_IMPL)\n";
255   OS << "EvalEmitter\n";
256   OS << "#else\n";
257   OS << "ByteCodeEmitter\n";
258   OS << "#endif\n";
259   OS << "::emit" << N << "(";
260   for (size_t I = 0, N = Types->size(); I < N; ++I)
261     OS << "PrimType T" << I << ", ";
262   for (size_t I = 0, N = Args.size(); I < N; ++I)
263     OS << Args[I]->getValueAsString("Name") << " A" << I << ", ";
264   OS << "const SourceInfo &I) {\n";
265 
266   std::function<void(size_t, const Twine &)> Rec;
267   llvm::SmallVector<Record *, 2> TS;
268   Rec = [this, &Rec, &OS, Types, &Args, R, &TS, N](size_t I, const Twine &ID) {
269     if (I >= Types->size()) {
270       // Print a call to the emitter method.
271       // Custom evaluator methods dispatch to template methods.
272       if (R->getValueAsBit("HasCustomEval")) {
273         OS << "#ifdef GET_LINK_IMPL\n";
274         OS << "return emit" << ID << "\n";
275         OS << "#else\n";
276         OS << "return emit" << N;
277         PrintTypes(OS, TS);
278         OS << "\n#endif\n";
279       } else {
280         OS << "return emit" << ID;
281       }
282 
283       OS << "(";
284       for (size_t I = 0; I < Args.size(); ++I) {
285         OS << "A" << I << ", ";
286       }
287       OS << "I);\n";
288       return;
289     }
290 
291     // Print a switch statement selecting T.
292     if (auto *TypeClass = dyn_cast<DefInit>(Types->getElement(I))) {
293       OS << "switch (T" << I << "){\n";
294       auto Cases = TypeClass->getDef()->getValueAsListOfDefs("Types");
295       for (auto *Case : Cases) {
296         OS << "case PT_" << Case->getName() << ":\n";
297         TS.push_back(Case);
298         Rec(I + 1, ID + Case->getName());
299         TS.pop_back();
300       }
301       // Emit a default case if not all types are present.
302       if (Cases.size() < NumTypes)
303         OS << "default: llvm_unreachable(\"invalid type\");\n";
304       OS << "}\n";
305       OS << "llvm_unreachable(\"invalid enum value\");\n";
306     } else {
307       PrintFatalError("Expected a type class");
308     }
309   };
310   Rec(0, N);
311 
312   OS << "}\n";
313   OS << "#endif\n";
314 }
315 
316 void ClangOpcodesEmitter::EmitEval(raw_ostream &OS, StringRef N, Record *R) {
317   if (R->getValueAsBit("HasCustomEval"))
318     return;
319 
320   OS << "#ifdef GET_EVAL_IMPL\n";
321   Enumerate(R, N, [this, R, &N, &OS](ArrayRef<Record *> TS, const Twine &ID) {
322     auto Args = R->getValueAsListOfDefs("Args");
323 
324     OS << "bool EvalEmitter::emit" << ID << "(";
325     for (size_t I = 0, N = Args.size(); I < N; ++I)
326       OS << Args[I]->getValueAsString("Name") << " A" << I << ",";
327     OS << "const SourceInfo &L) {\n";
328     OS << "if (!isActive()) return true;\n";
329     OS << "CurrentSource = L;\n";
330 
331     OS << "return " << N;
332     PrintTypes(OS, TS);
333     OS << "(S, OpPC";
334     for (size_t I = 0, N = Args.size(); I < N; ++I)
335       OS << ", A" << I;
336     OS << ");\n";
337     OS << "}\n";
338   });
339 
340   OS << "#endif\n";
341 }
342 
343 void ClangOpcodesEmitter::PrintTypes(raw_ostream &OS, ArrayRef<Record *> Types) {
344   if (Types.empty())
345     return;
346   OS << "<";
347   for (size_t I = 0, N = Types.size(); I < N; ++I) {
348     if (I != 0)
349       OS << ", ";
350     OS << "PT_" << Types[I]->getName();
351   }
352   OS << ">";
353 }
354 
355 void clang::EmitClangOpcodes(RecordKeeper &Records, raw_ostream &OS) {
356   ClangOpcodesEmitter(Records).run(OS);
357 }
358