1 //===- ClangSyntaxEmitter.cpp - Generate clang Syntax Tree nodes ----------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 6 // See https://llvm.org/LICENSE.txt for license information. 7 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 8 // 9 //===----------------------------------------------------------------------===// 10 // 11 // These backends consume the definitions of Syntax Tree nodes. 12 // See clang/include/clang/Tooling/Syntax/{Syntax,Nodes}.td 13 // 14 // The -gen-clang-syntax-node-list backend produces a .inc with macro calls 15 // NODE(Kind, BaseKind) 16 // ABSTRACT_NODE(Type, Base, FirstKind, LastKind) 17 // similar to those for AST nodes such as AST/DeclNodes.inc. 18 // 19 // The -gen-clang-syntax-node-classes backend produces definitions for the 20 // syntax::Node subclasses (except those marked as External). 21 // 22 // In future, another backend will encode the structure of the various node 23 // types in tables so their invariants can be checked and enforced. 24 // 25 //===----------------------------------------------------------------------===// 26 #include "TableGenBackends.h" 27 28 #include <deque> 29 30 #include "llvm/ADT/StringExtras.h" 31 #include "llvm/Support/FormatVariadic.h" 32 #include "llvm/Support/raw_ostream.h" 33 #include "llvm/TableGen/Record.h" 34 #include "llvm/TableGen/TableGenBackend.h" 35 36 namespace { 37 using llvm::formatv; 38 39 // The class hierarchy of Node types. 40 // We assemble this in order to be able to define the NodeKind enum in a 41 // stable and useful way, where abstract Node subclasses correspond to ranges. 42 class Hierarchy { 43 public: 44 Hierarchy(const llvm::RecordKeeper &Records) { 45 for (llvm::Record *T : Records.getAllDerivedDefinitions("NodeType")) 46 add(T); 47 for (llvm::Record *Derived : Records.getAllDerivedDefinitions("NodeType")) 48 if (llvm::Record *Base = Derived->getValueAsOptionalDef("base")) 49 link(Derived, Base); 50 for (NodeType &N : AllTypes) { 51 llvm::sort(N.Derived, [](const NodeType *L, const NodeType *R) { 52 return L->Record->getName() < R->Record->getName(); 53 }); 54 // Alternatives nodes must have subclasses, External nodes may do. 55 assert(N.Record->isSubClassOf("Alternatives") || 56 N.Record->isSubClassOf("External") || N.Derived.empty()); 57 assert(!N.Record->isSubClassOf("Alternatives") || !N.Derived.empty()); 58 } 59 } 60 61 struct NodeType { 62 const llvm::Record *Record = nullptr; 63 const NodeType *Base = nullptr; 64 std::vector<const NodeType *> Derived; 65 llvm::StringRef name() const { return Record->getName(); } 66 }; 67 68 NodeType &get(llvm::StringRef Name = "Node") { 69 auto NI = ByName.find(Name); 70 assert(NI != ByName.end() && "no such node"); 71 return *NI->second; 72 } 73 74 // Traverse the hierarchy in pre-order (base classes before derived). 75 void visit(llvm::function_ref<void(const NodeType &)> CB, 76 const NodeType *Start = nullptr) { 77 if (Start == nullptr) 78 Start = &get(); 79 CB(*Start); 80 for (const NodeType *D : Start->Derived) 81 visit(CB, D); 82 } 83 84 private: 85 void add(const llvm::Record *R) { 86 AllTypes.emplace_back(); 87 AllTypes.back().Record = R; 88 bool Inserted = ByName.try_emplace(R->getName(), &AllTypes.back()).second; 89 assert(Inserted && "Duplicate node name"); 90 (void)Inserted; 91 } 92 93 void link(const llvm::Record *Derived, const llvm::Record *Base) { 94 auto &CN = get(Derived->getName()), &PN = get(Base->getName()); 95 assert(CN.Base == nullptr && "setting base twice"); 96 PN.Derived.push_back(&CN); 97 CN.Base = &PN; 98 } 99 100 std::deque<NodeType> AllTypes; 101 llvm::DenseMap<llvm::StringRef, NodeType *> ByName; 102 }; 103 104 const Hierarchy::NodeType &firstConcrete(const Hierarchy::NodeType &N) { 105 return N.Derived.empty() ? N : firstConcrete(*N.Derived.front()); 106 } 107 const Hierarchy::NodeType &lastConcrete(const Hierarchy::NodeType &N) { 108 return N.Derived.empty() ? N : lastConcrete(*N.Derived.back()); 109 } 110 111 struct SyntaxConstraint { 112 SyntaxConstraint(const llvm::Record &R) { 113 if (R.isSubClassOf("Optional")) { 114 *this = SyntaxConstraint(*R.getValueAsDef("inner")); 115 } else if (R.isSubClassOf("AnyToken")) { 116 NodeType = "Leaf"; 117 } else if (R.isSubClassOf("NodeType")) { 118 NodeType = R.getName().str(); 119 } else { 120 assert(false && "Unhandled Syntax kind"); 121 } 122 } 123 124 std::string NodeType; 125 // optional and leaf types also go here, once we want to use them. 126 }; 127 128 } // namespace 129 130 void clang::EmitClangSyntaxNodeList(llvm::RecordKeeper &Records, 131 llvm::raw_ostream &OS) { 132 llvm::emitSourceFileHeader("Syntax tree node list", OS, Records); 133 Hierarchy H(Records); 134 OS << R"cpp( 135 #ifndef NODE 136 #define NODE(Kind, Base) 137 #endif 138 139 #ifndef CONCRETE_NODE 140 #define CONCRETE_NODE(Kind, Base) NODE(Kind, Base) 141 #endif 142 143 #ifndef ABSTRACT_NODE 144 #define ABSTRACT_NODE(Kind, Base, First, Last) NODE(Kind, Base) 145 #endif 146 147 )cpp"; 148 H.visit([&](const Hierarchy::NodeType &N) { 149 // Don't emit ABSTRACT_NODE for node itself, which has no parent. 150 if (N.Base == nullptr) 151 return; 152 if (N.Derived.empty()) 153 OS << formatv("CONCRETE_NODE({0},{1})\n", N.name(), N.Base->name()); 154 else 155 OS << formatv("ABSTRACT_NODE({0},{1},{2},{3})\n", N.name(), 156 N.Base->name(), firstConcrete(N).name(), 157 lastConcrete(N).name()); 158 }); 159 OS << R"cpp( 160 #undef NODE 161 #undef CONCRETE_NODE 162 #undef ABSTRACT_NODE 163 )cpp"; 164 } 165 166 // Format a documentation string as a C++ comment. 167 // Trims leading whitespace handling since comments come from a TableGen file: 168 // documentation = [{ 169 // This is a widget. Example: 170 // widget.explode() 171 // }]; 172 // and should be formatted as: 173 // /// This is a widget. Example: 174 // /// widget.explode() 175 // Leading and trailing whitespace lines are stripped. 176 // The indentation of the first line is stripped from all lines. 177 static void printDoc(llvm::StringRef Doc, llvm::raw_ostream &OS) { 178 Doc = Doc.rtrim(); 179 llvm::StringRef Line; 180 while (Line.trim().empty() && !Doc.empty()) 181 std::tie(Line, Doc) = Doc.split('\n'); 182 llvm::StringRef Indent = Line.take_while(llvm::isSpace); 183 for (; !Line.empty() || !Doc.empty(); std::tie(Line, Doc) = Doc.split('\n')) { 184 Line.consume_front(Indent); 185 OS << "/// " << Line << "\n"; 186 } 187 } 188 189 void clang::EmitClangSyntaxNodeClasses(llvm::RecordKeeper &Records, 190 llvm::raw_ostream &OS) { 191 llvm::emitSourceFileHeader("Syntax tree node list", OS, Records); 192 Hierarchy H(Records); 193 194 OS << "\n// Forward-declare node types so we don't have to carefully " 195 "sequence definitions.\n"; 196 H.visit([&](const Hierarchy::NodeType &N) { 197 OS << "class " << N.name() << ";\n"; 198 }); 199 200 OS << "\n// Node definitions\n\n"; 201 H.visit([&](const Hierarchy::NodeType &N) { 202 if (N.Record->isSubClassOf("External")) 203 return; 204 printDoc(N.Record->getValueAsString("documentation"), OS); 205 OS << formatv("class {0}{1} : public {2} {{\n", N.name(), 206 N.Derived.empty() ? " final" : "", N.Base->name()); 207 208 // Constructor. 209 if (N.Derived.empty()) 210 OS << formatv("public:\n {0}() : {1}(NodeKind::{0}) {{}\n", N.name(), 211 N.Base->name()); 212 else 213 OS << formatv("protected:\n {0}(NodeKind K) : {1}(K) {{}\npublic:\n", 214 N.name(), N.Base->name()); 215 216 if (N.Record->isSubClassOf("Sequence")) { 217 // Getters for sequence elements. 218 for (const auto &C : N.Record->getValueAsListOfDefs("children")) { 219 assert(C->isSubClassOf("Role")); 220 llvm::StringRef Role = C->getValueAsString("role"); 221 SyntaxConstraint Constraint(*C->getValueAsDef("syntax")); 222 for (const char *Const : {"", "const "}) 223 OS << formatv( 224 " {2}{1} *get{0}() {2} {{\n" 225 " return llvm::cast_or_null<{1}>(findChild(NodeRole::{0}));\n" 226 " }\n", 227 Role, Constraint.NodeType, Const); 228 } 229 } 230 231 // classof. FIXME: move definition inline once ~all nodes are generated. 232 OS << " static bool classof(const Node *N);\n"; 233 234 OS << "};\n\n"; 235 }); 236 } 237