1 //=== ClangASTNodesEmitter.cpp - Generate Clang AST node tables -*- 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 "ASTTableGen.h"
14 #include "TableGenBackends.h"
15 
16 #include "llvm/TableGen/Error.h"
17 #include "llvm/TableGen/Record.h"
18 #include "llvm/TableGen/TableGenBackend.h"
19 #include <cctype>
20 #include <map>
21 #include <set>
22 #include <string>
23 using namespace llvm;
24 using namespace clang;
25 using namespace clang::tblgen;
26 
27 /// ClangASTNodesEmitter - The top-level class emits .inc files containing
28 ///  declarations of Clang statements.
29 ///
30 namespace {
31 class ClangASTNodesEmitter {
32   // A map from a node to each of its derived nodes.
33   typedef std::multimap<ASTNode, ASTNode> ChildMap;
34   typedef ChildMap::const_iterator ChildIterator;
35 
36   RecordKeeper &Records;
37   ASTNode Root;
38   const std::string &NodeClassName;
39   const std::string &BaseSuffix;
40   std::string MacroHierarchyName;
41   ChildMap Tree;
42 
43   // Create a macro-ized version of a name
44   static std::string macroName(std::string S) {
45     for (unsigned i = 0; i < S.size(); ++i)
46       S[i] = std::toupper(S[i]);
47 
48     return S;
49   }
50 
51   const std::string &macroHierarchyName() {
52     assert(Root && "root node not yet derived!");
53     if (MacroHierarchyName.empty())
54       MacroHierarchyName = macroName(std::string(Root.getName()));
55     return MacroHierarchyName;
56   }
57 
58   // Return the name to be printed in the base field. Normally this is
59   // the record's name plus the base suffix, but if it is the root node and
60   // the suffix is non-empty, it's just the suffix.
61   std::string baseName(ASTNode node) {
62     if (node == Root && !BaseSuffix.empty())
63       return BaseSuffix;
64 
65     return node.getName().str() + BaseSuffix;
66   }
67 
68   void deriveChildTree();
69 
70   std::pair<ASTNode, ASTNode> EmitNode(raw_ostream& OS, ASTNode Base);
71 public:
72   explicit ClangASTNodesEmitter(RecordKeeper &R, const std::string &N,
73                                 const std::string &S)
74     : Records(R), NodeClassName(N), BaseSuffix(S) {}
75 
76   // run - Output the .inc file contents
77   void run(raw_ostream &OS);
78 };
79 } // end anonymous namespace
80 
81 //===----------------------------------------------------------------------===//
82 // Statement Node Tables (.inc file) generation.
83 //===----------------------------------------------------------------------===//
84 
85 // Returns the first and last non-abstract subrecords
86 // Called recursively to ensure that nodes remain contiguous
87 std::pair<ASTNode, ASTNode> ClangASTNodesEmitter::EmitNode(raw_ostream &OS,
88                                                            ASTNode Base) {
89   std::string BaseName = macroName(std::string(Base.getName()));
90 
91   ChildIterator i = Tree.lower_bound(Base), e = Tree.upper_bound(Base);
92   bool HasChildren = (i != e);
93 
94   ASTNode First, Last;
95   if (!Base.isAbstract())
96     First = Last = Base;
97 
98   for (; i != e; ++i) {
99     ASTNode Child = i->second;
100     bool Abstract = Child.isAbstract();
101     std::string NodeName = macroName(std::string(Child.getName()));
102 
103     OS << "#ifndef " << NodeName << "\n";
104     OS << "#  define " << NodeName << "(Type, Base) "
105         << BaseName << "(Type, Base)\n";
106     OS << "#endif\n";
107 
108     if (Abstract) OS << "ABSTRACT_" << macroHierarchyName() << "(";
109     OS << NodeName << "(" << Child.getName() << ", " << baseName(Base) << ")";
110     if (Abstract) OS << ")";
111     OS << "\n";
112 
113     auto Result = EmitNode(OS, Child);
114     assert(Result.first && Result.second && "node didn't have children?");
115 
116     // Update the range of Base.
117     if (!First) First = Result.first;
118     Last = Result.second;
119 
120     OS << "#undef " << NodeName << "\n\n";
121   }
122 
123   // If there aren't first/last nodes, it must be because there were no
124   // children and this node was abstract, which is not a sensible combination.
125   if (!First) {
126     PrintFatalError(Base.getLoc(), "abstract node has no children");
127   }
128   assert(Last && "set First without Last");
129 
130   if (HasChildren) {
131     // Use FOO_RANGE unless this is the last of the ranges, in which case
132     // use LAST_FOO_RANGE.
133     if (Base == Root)
134       OS << "LAST_" << macroHierarchyName() << "_RANGE(";
135     else
136       OS << macroHierarchyName() << "_RANGE(";
137     OS << Base.getName() << ", " << First.getName() << ", "
138        << Last.getName() << ")\n\n";
139   }
140 
141   return std::make_pair(First, Last);
142 }
143 
144 void ClangASTNodesEmitter::deriveChildTree() {
145   assert(!Root && "already computed tree");
146 
147   // Emit statements
148   const std::vector<Record*> Stmts
149     = Records.getAllDerivedDefinitions(NodeClassName);
150 
151   for (unsigned i = 0, e = Stmts.size(); i != e; ++i) {
152     Record *R = Stmts[i];
153 
154     if (auto B = R->getValueAsOptionalDef(BaseFieldName))
155       Tree.insert(std::make_pair(B, R));
156     else if (Root)
157       PrintFatalError(R->getLoc(),
158                       Twine("multiple root nodes in \"") + NodeClassName
159                         + "\" hierarchy");
160     else
161       Root = R;
162   }
163 
164   if (!Root)
165     PrintFatalError(Twine("didn't find root node in \"") + NodeClassName
166                       + "\" hierarchy");
167 }
168 
169 void ClangASTNodesEmitter::run(raw_ostream &OS) {
170   deriveChildTree();
171 
172   emitSourceFileHeader("List of AST nodes of a particular kind", OS);
173 
174   // Write the preamble
175   OS << "#ifndef ABSTRACT_" << macroHierarchyName() << "\n";
176   OS << "#  define ABSTRACT_" << macroHierarchyName() << "(Type) Type\n";
177   OS << "#endif\n";
178 
179   OS << "#ifndef " << macroHierarchyName() << "_RANGE\n";
180   OS << "#  define "
181      << macroHierarchyName() << "_RANGE(Base, First, Last)\n";
182   OS << "#endif\n\n";
183 
184   OS << "#ifndef LAST_" << macroHierarchyName() << "_RANGE\n";
185   OS << "#  define LAST_"
186      << macroHierarchyName() << "_RANGE(Base, First, Last) "
187      << macroHierarchyName() << "_RANGE(Base, First, Last)\n";
188   OS << "#endif\n\n";
189 
190   EmitNode(OS, Root);
191 
192   OS << "#undef " << macroHierarchyName() << "\n";
193   OS << "#undef " << macroHierarchyName() << "_RANGE\n";
194   OS << "#undef LAST_" << macroHierarchyName() << "_RANGE\n";
195   OS << "#undef ABSTRACT_" << macroHierarchyName() << "\n";
196 }
197 
198 void clang::EmitClangASTNodes(RecordKeeper &RK, raw_ostream &OS,
199                               const std::string &N, const std::string &S) {
200   ClangASTNodesEmitter(RK, N, S).run(OS);
201 }
202 
203 // Emits and addendum to a .inc file to enumerate the clang declaration
204 // contexts.
205 void clang::EmitClangDeclContext(RecordKeeper &Records, raw_ostream &OS) {
206   // FIXME: Find a .td file format to allow for this to be represented better.
207 
208   emitSourceFileHeader("List of AST Decl nodes", OS);
209 
210   OS << "#ifndef DECL_CONTEXT\n";
211   OS << "#  define DECL_CONTEXT(DECL)\n";
212   OS << "#endif\n";
213 
214   OS << "#ifndef DECL_CONTEXT_BASE\n";
215   OS << "#  define DECL_CONTEXT_BASE(DECL) DECL_CONTEXT(DECL)\n";
216   OS << "#endif\n";
217 
218   typedef std::set<Record*> RecordSet;
219   typedef std::vector<Record*> RecordVector;
220 
221   RecordVector DeclContextsVector
222     = Records.getAllDerivedDefinitions(DeclContextNodeClassName);
223   RecordVector Decls = Records.getAllDerivedDefinitions(DeclNodeClassName);
224   RecordSet DeclContexts (DeclContextsVector.begin(), DeclContextsVector.end());
225 
226   for (RecordVector::iterator i = Decls.begin(), e = Decls.end(); i != e; ++i) {
227     Record *R = *i;
228 
229     if (Record *B = R->getValueAsOptionalDef(BaseFieldName)) {
230       if (DeclContexts.find(B) != DeclContexts.end()) {
231         OS << "DECL_CONTEXT_BASE(" << B->getName() << ")\n";
232         DeclContexts.erase(B);
233       }
234     }
235   }
236 
237   // To keep identical order, RecordVector may be used
238   // instead of RecordSet.
239   for (RecordVector::iterator
240          i = DeclContextsVector.begin(), e = DeclContextsVector.end();
241        i != e; ++i)
242     if (DeclContexts.find(*i) != DeclContexts.end())
243       OS << "DECL_CONTEXT(" << (*i)->getName() << ")\n";
244 
245   OS << "#undef DECL_CONTEXT\n";
246   OS << "#undef DECL_CONTEXT_BASE\n";
247 }
248