1 //===---- QueryParser.cpp - clang-query command parser --------------------===//
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 #include "QueryParser.h"
11 #include "Query.h"
12 #include "QuerySession.h"
13 #include "clang/ASTMatchers/Dynamic/Parser.h"
14 #include "clang/Basic/CharInfo.h"
15 #include "llvm/ADT/StringRef.h"
16 #include "llvm/ADT/StringSwitch.h"
17 #include <set>
18 
19 using namespace llvm;
20 using namespace clang::ast_matchers::dynamic;
21 
22 namespace clang {
23 namespace query {
24 
25 // Lex any amount of whitespace followed by a "word" (any sequence of
26 // non-whitespace characters) from the start of region [Begin,End).  If no word
27 // is found before End, return StringRef().  Begin is adjusted to exclude the
28 // lexed region.
29 StringRef QueryParser::lexWord() {
30   while (true) {
31     if (Begin == End)
32       return StringRef(Begin, 0);
33 
34     if (!isWhitespace(*Begin))
35       break;
36 
37     ++Begin;
38   }
39 
40   const char *WordBegin = Begin;
41 
42   while (true) {
43     ++Begin;
44 
45     if (Begin == End || isWhitespace(*Begin))
46       return StringRef(WordBegin, Begin - WordBegin);
47   }
48 }
49 
50 // This is the StringSwitch-alike used by lexOrCompleteWord below. See that
51 // function for details.
52 template <typename T> struct QueryParser::LexOrCompleteWord {
53   StringSwitch<T> Switch;
54 
55   QueryParser *P;
56   StringRef Word;
57   // Set to the completion point offset in Word, or StringRef::npos if
58   // completion point not in Word.
59   size_t WordCompletionPos;
60 
61   LexOrCompleteWord(QueryParser *P, StringRef Word, size_t WCP)
62       : Switch(Word), P(P), Word(Word), WordCompletionPos(WCP) {}
63 
64   template <unsigned N>
65   LexOrCompleteWord &Case(const char (&S)[N], const T &Value,
66                           bool IsCompletion = true) {
67     StringRef CaseStr(S, N - 1);
68 
69     if (WordCompletionPos == StringRef::npos)
70       Switch.Case(S, Value);
71     else if (N != 1 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
72              CaseStr.substr(0, WordCompletionPos) ==
73                  Word.substr(0, WordCompletionPos))
74       P->Completions.push_back(LineEditor::Completion(
75           (CaseStr.substr(WordCompletionPos) + " ").str(), CaseStr));
76     return *this;
77   }
78 
79   T Default(const T& Value) const {
80     return Switch.Default(Value);
81   }
82 };
83 
84 // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
85 // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
86 // completions if the lexed word contains the completion point.
87 template <typename T>
88 QueryParser::LexOrCompleteWord<T>
89 QueryParser::lexOrCompleteWord(StringRef &Word) {
90   Word = lexWord();
91   size_t WordCompletionPos = StringRef::npos;
92   if (CompletionPos && CompletionPos <= Word.data() + Word.size()) {
93     if (CompletionPos < Word.data())
94       WordCompletionPos = 0;
95     else
96       WordCompletionPos = CompletionPos - Word.data();
97   }
98   return LexOrCompleteWord<T>(this, Word, WordCompletionPos);
99 }
100 
101 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
102   StringRef ValStr;
103   unsigned Value = lexOrCompleteWord<unsigned>(ValStr)
104                       .Case("false", 0)
105                       .Case("true", 1)
106                       .Default(~0u);
107   if (Value == ~0u) {
108     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
109   }
110   return new SetQuery<bool>(Var, Value);
111 }
112 
113 QueryRef QueryParser::parseSetOutputKind() {
114   StringRef ValStr;
115   unsigned OutKind = lexOrCompleteWord<unsigned>(ValStr)
116                          .Case("diag", OK_Diag)
117                          .Case("print", OK_Print)
118                          .Case("dump", OK_Dump)
119                          .Default(~0u);
120   if (OutKind == ~0u) {
121     return new InvalidQuery("expected 'diag', 'print' or 'dump', got '" +
122                             ValStr + "'");
123   }
124   return new SetQuery<OutputKind>(&QuerySession::OutKind, OutputKind(OutKind));
125 }
126 
127 QueryRef QueryParser::endQuery(QueryRef Q) {
128   const char *Extra = Begin;
129   if (!lexWord().empty())
130     return new InvalidQuery("unexpected extra input: '" +
131                             StringRef(Extra, End - Extra) + "'");
132   return Q;
133 }
134 
135 namespace {
136 
137 enum ParsedQueryKind {
138   PQK_Invalid,
139   PQK_NoOp,
140   PQK_Help,
141   PQK_Let,
142   PQK_Match,
143   PQK_Set,
144   PQK_Unlet,
145   PQK_Quit
146 };
147 
148 enum ParsedQueryVariable {
149   PQV_Invalid,
150   PQV_Output,
151   PQV_BindRoot
152 };
153 
154 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
155   std::string ErrStr;
156   llvm::raw_string_ostream OS(ErrStr);
157   Diag.printToStreamFull(OS);
158   return new InvalidQuery(OS.str());
159 }
160 
161 }  // namespace
162 
163 QueryRef QueryParser::completeMatcherExpression() {
164   std::vector<MatcherCompletion> Comps = Parser::completeExpression(
165       StringRef(Begin, End - Begin), CompletionPos - Begin, nullptr,
166       &QS.NamedValues);
167   for (std::vector<MatcherCompletion>::iterator I = Comps.begin(),
168                                                 E = Comps.end();
169        I != E; ++I) {
170     Completions.push_back(LineEditor::Completion(I->TypedText, I->MatcherDecl));
171   }
172   return QueryRef();
173 }
174 
175 QueryRef QueryParser::doParse() {
176   StringRef CommandStr;
177   ParsedQueryKind QKind = lexOrCompleteWord<ParsedQueryKind>(CommandStr)
178                               .Case("", PQK_NoOp)
179                               .Case("help", PQK_Help)
180                               .Case("m", PQK_Match, /*IsCompletion=*/false)
181                               .Case("let", PQK_Let)
182                               .Case("match", PQK_Match)
183                               .Case("set", PQK_Set)
184                               .Case("unlet", PQK_Unlet)
185                               .Case("quit", PQK_Quit)
186                               .Default(PQK_Invalid);
187 
188   switch (QKind) {
189   case PQK_NoOp:
190     return new NoOpQuery;
191 
192   case PQK_Help:
193     return endQuery(new HelpQuery);
194 
195   case PQK_Quit:
196     return endQuery(new QuitQuery);
197 
198   case PQK_Let: {
199     StringRef Name = lexWord();
200 
201     if (Name.empty())
202       return new InvalidQuery("expected variable name");
203 
204     if (CompletionPos)
205       return completeMatcherExpression();
206 
207     Diagnostics Diag;
208     ast_matchers::dynamic::VariantValue Value;
209     if (!Parser::parseExpression(StringRef(Begin, End - Begin), nullptr,
210                                  &QS.NamedValues, &Value, &Diag)) {
211       return makeInvalidQueryFromDiagnostics(Diag);
212     }
213 
214     return new LetQuery(Name, Value);
215   }
216 
217   case PQK_Match: {
218     if (CompletionPos)
219       return completeMatcherExpression();
220 
221     Diagnostics Diag;
222     Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
223         StringRef(Begin, End - Begin), nullptr, &QS.NamedValues, &Diag);
224     if (!Matcher) {
225       return makeInvalidQueryFromDiagnostics(Diag);
226     }
227     return new MatchQuery(*Matcher);
228   }
229 
230   case PQK_Set: {
231     StringRef VarStr;
232     ParsedQueryVariable Var = lexOrCompleteWord<ParsedQueryVariable>(VarStr)
233                                   .Case("output", PQV_Output)
234                                   .Case("bind-root", PQV_BindRoot)
235                                   .Default(PQV_Invalid);
236     if (VarStr.empty())
237       return new InvalidQuery("expected variable name");
238     if (Var == PQV_Invalid)
239       return new InvalidQuery("unknown variable: '" + VarStr + "'");
240 
241     QueryRef Q;
242     switch (Var) {
243     case PQV_Output:
244       Q = parseSetOutputKind();
245       break;
246     case PQV_BindRoot:
247       Q = parseSetBool(&QuerySession::BindRoot);
248       break;
249     case PQV_Invalid:
250       llvm_unreachable("Invalid query kind");
251     }
252 
253     return endQuery(Q);
254   }
255 
256   case PQK_Unlet: {
257     StringRef Name = lexWord();
258 
259     if (Name.empty())
260       return new InvalidQuery("expected variable name");
261 
262     return endQuery(new LetQuery(Name, VariantValue()));
263   }
264 
265   case PQK_Invalid:
266     return new InvalidQuery("unknown command: " + CommandStr);
267   }
268 
269   llvm_unreachable("Invalid query kind");
270 }
271 
272 QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
273   return QueryParser(Line, QS).doParse();
274 }
275 
276 std::vector<LineEditor::Completion>
277 QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
278   QueryParser P(Line, QS);
279   P.CompletionPos = Line.data() + Pos;
280 
281   P.doParse();
282   return P.Completions;
283 }
284 
285 } // namespace query
286 } // namespace clang
287