1 //===---- QueryParser.cpp - clang-query command parser --------------------===//
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 #include "QueryParser.h"
10 #include "Query.h"
11 #include "QuerySession.h"
12 #include "clang/ASTMatchers/Dynamic/Parser.h"
13 #include "clang/Basic/CharInfo.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/ADT/StringSwitch.h"
16 #include <set>
17 
18 using namespace llvm;
19 using namespace clang::ast_matchers::dynamic;
20 
21 namespace clang {
22 namespace query {
23 
24 // Lex any amount of whitespace followed by a "word" (any sequence of
25 // non-whitespace characters) from the start of region [Begin,End).  If no word
26 // is found before End, return StringRef().  Begin is adjusted to exclude the
27 // lexed region.
28 StringRef QueryParser::lexWord() {
29   Line = Line.drop_while([](char c) {
30     // Don't trim newlines.
31     return StringRef(" \t\v\f\r").contains(c);
32   });
33 
34   if (Line.empty())
35     // Even though the Line is empty, it contains a pointer and
36     // a (zero) length. The pointer is used in the LexOrCompleteWord
37     // code completion.
38     return Line;
39 
40   StringRef Word;
41   if (Line.front() == '#')
42     Word = Line.substr(0, 1);
43   else
44     Word = Line.take_until(isWhitespace);
45 
46   Line = Line.drop_front(Word.size());
47   return Word;
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   StringRef Word;
54   StringSwitch<T> Switch;
55 
56   QueryParser *P;
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   // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
62   // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
63   // completions if the lexed word contains the completion point.
64   LexOrCompleteWord(QueryParser *P, StringRef &OutWord)
65       : Word(P->lexWord()), Switch(Word), P(P),
66         WordCompletionPos(StringRef::npos) {
67     OutWord = Word;
68     if (P->CompletionPos && P->CompletionPos <= Word.data() + Word.size()) {
69       if (P->CompletionPos < Word.data())
70         WordCompletionPos = 0;
71       else
72         WordCompletionPos = P->CompletionPos - Word.data();
73     }
74   }
75 
76   LexOrCompleteWord &Case(llvm::StringLiteral CaseStr, const T &Value,
77                           bool IsCompletion = true) {
78 
79     if (WordCompletionPos == StringRef::npos)
80       Switch.Case(CaseStr, Value);
81     else if (CaseStr.size() != 0 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
82              CaseStr.substr(0, WordCompletionPos) ==
83                  Word.substr(0, WordCompletionPos))
84       P->Completions.push_back(LineEditor::Completion(
85           (CaseStr.substr(WordCompletionPos) + " ").str(),
86           std::string(CaseStr)));
87     return *this;
88   }
89 
90   T Default(T Value) { return Switch.Default(Value); }
91 };
92 
93 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
94   StringRef ValStr;
95   unsigned Value = LexOrCompleteWord<unsigned>(this, ValStr)
96                        .Case("false", 0)
97                        .Case("true", 1)
98                        .Default(~0u);
99   if (Value == ~0u) {
100     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
101   }
102   return new SetQuery<bool>(Var, Value);
103 }
104 
105 template <typename QueryType> QueryRef QueryParser::parseSetOutputKind() {
106   StringRef ValStr;
107   unsigned OutKind = LexOrCompleteWord<unsigned>(this, ValStr)
108                          .Case("diag", OK_Diag)
109                          .Case("print", OK_Print)
110                          .Case("detailed-ast", OK_DetailedAST)
111                          .Case("dump", OK_DetailedAST)
112                          .Default(~0u);
113   if (OutKind == ~0u) {
114     return new InvalidQuery(
115         "expected 'diag', 'print', 'detailed-ast' or 'dump', got '" + ValStr +
116         "'");
117   }
118 
119   switch (OutKind) {
120   case OK_DetailedAST:
121     return new QueryType(&QuerySession::DetailedASTOutput);
122   case OK_Diag:
123     return new QueryType(&QuerySession::DiagOutput);
124   case OK_Print:
125     return new QueryType(&QuerySession::PrintOutput);
126   }
127 
128   llvm_unreachable("Invalid output kind");
129 }
130 
131 QueryRef QueryParser::parseSetTraversalKind(TraversalKind QuerySession::*Var) {
132   StringRef ValStr;
133   unsigned Value =
134       LexOrCompleteWord<unsigned>(this, ValStr)
135           .Case("AsIs", TK_AsIs)
136           .Case("IgnoreUnlessSpelledInSource", TK_IgnoreUnlessSpelledInSource)
137           .Default(~0u);
138   if (Value == ~0u) {
139     return new InvalidQuery("expected traversal kind, got '" + ValStr + "'");
140   }
141   return new SetQuery<TraversalKind>(Var, static_cast<TraversalKind>(Value));
142 }
143 
144 QueryRef QueryParser::endQuery(QueryRef Q) {
145   StringRef Extra = Line;
146   StringRef ExtraTrimmed = Extra.drop_while(
147       [](char c) { return StringRef(" \t\v\f\r").contains(c); });
148 
149   if ((!ExtraTrimmed.empty() && ExtraTrimmed[0] == '\n') ||
150       (ExtraTrimmed.size() >= 2 && ExtraTrimmed[0] == '\r' &&
151        ExtraTrimmed[1] == '\n'))
152     Q->RemainingContent = Extra;
153   else {
154     StringRef TrailingWord = lexWord();
155     if (!TrailingWord.empty() && TrailingWord.front() == '#') {
156       Line = Line.drop_until([](char c) { return c == '\n'; });
157       Line = Line.drop_while([](char c) { return c == '\n'; });
158       return endQuery(Q);
159     }
160     if (!TrailingWord.empty()) {
161       return new InvalidQuery("unexpected extra input: '" + Extra + "'");
162     }
163   }
164   return Q;
165 }
166 
167 namespace {
168 
169 enum ParsedQueryKind {
170   PQK_Invalid,
171   PQK_Comment,
172   PQK_NoOp,
173   PQK_Help,
174   PQK_Let,
175   PQK_Match,
176   PQK_Set,
177   PQK_Unlet,
178   PQK_Quit,
179   PQK_Enable,
180   PQK_Disable
181 };
182 
183 enum ParsedQueryVariable {
184   PQV_Invalid,
185   PQV_Output,
186   PQV_BindRoot,
187   PQV_PrintMatcher,
188   PQV_Traversal
189 };
190 
191 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
192   std::string ErrStr;
193   llvm::raw_string_ostream OS(ErrStr);
194   Diag.printToStreamFull(OS);
195   return new InvalidQuery(OS.str());
196 }
197 
198 } // namespace
199 
200 QueryRef QueryParser::completeMatcherExpression() {
201   std::vector<MatcherCompletion> Comps = Parser::completeExpression(
202       Line, CompletionPos - Line.begin(), nullptr, &QS.NamedValues);
203   for (auto I = Comps.begin(), E = Comps.end(); I != E; ++I) {
204     Completions.push_back(LineEditor::Completion(I->TypedText, I->MatcherDecl));
205   }
206   return QueryRef();
207 }
208 
209 QueryRef QueryParser::doParse() {
210   StringRef CommandStr;
211   ParsedQueryKind QKind = LexOrCompleteWord<ParsedQueryKind>(this, CommandStr)
212                               .Case("", PQK_NoOp)
213                               .Case("#", PQK_Comment, /*IsCompletion=*/false)
214                               .Case("help", PQK_Help)
215                               .Case("l", PQK_Let, /*IsCompletion=*/false)
216                               .Case("let", PQK_Let)
217                               .Case("m", PQK_Match, /*IsCompletion=*/false)
218                               .Case("match", PQK_Match)
219                               .Case("q", PQK_Quit,  /*IsCompletion=*/false)
220                               .Case("quit", PQK_Quit)
221                               .Case("set", PQK_Set)
222                               .Case("enable", PQK_Enable)
223                               .Case("disable", PQK_Disable)
224                               .Case("unlet", PQK_Unlet)
225                               .Default(PQK_Invalid);
226 
227   switch (QKind) {
228   case PQK_Comment:
229   case PQK_NoOp:
230     Line = Line.drop_until([](char c) { return c == '\n'; });
231     Line = Line.drop_while([](char c) { return c == '\n'; });
232     if (Line.empty())
233       return new NoOpQuery;
234     return doParse();
235 
236   case PQK_Help:
237     return endQuery(new HelpQuery);
238 
239   case PQK_Quit:
240     return endQuery(new QuitQuery);
241 
242   case PQK_Let: {
243     StringRef Name = lexWord();
244 
245     if (Name.empty())
246       return new InvalidQuery("expected variable name");
247 
248     if (CompletionPos)
249       return completeMatcherExpression();
250 
251     Diagnostics Diag;
252     ast_matchers::dynamic::VariantValue Value;
253     if (!Parser::parseExpression(Line, nullptr, &QS.NamedValues, &Value,
254                                  &Diag)) {
255       return makeInvalidQueryFromDiagnostics(Diag);
256     }
257 
258     auto *Q = new LetQuery(Name, Value);
259     Q->RemainingContent = Line;
260     return Q;
261   }
262 
263   case PQK_Match: {
264     if (CompletionPos)
265       return completeMatcherExpression();
266 
267     Diagnostics Diag;
268     auto MatcherSource = Line.ltrim();
269     auto OrigMatcherSource = MatcherSource;
270     Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
271         MatcherSource, nullptr, &QS.NamedValues, &Diag);
272     if (!Matcher) {
273       return makeInvalidQueryFromDiagnostics(Diag);
274     }
275     auto ActualSource = OrigMatcherSource.slice(0, OrigMatcherSource.size() -
276                                                        MatcherSource.size());
277     auto *Q = new MatchQuery(ActualSource, *Matcher);
278     Q->RemainingContent = MatcherSource;
279     return Q;
280   }
281 
282   case PQK_Set: {
283     StringRef VarStr;
284     ParsedQueryVariable Var =
285         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
286             .Case("output", PQV_Output)
287             .Case("bind-root", PQV_BindRoot)
288             .Case("print-matcher", PQV_PrintMatcher)
289             .Case("traversal", PQV_Traversal)
290             .Default(PQV_Invalid);
291     if (VarStr.empty())
292       return new InvalidQuery("expected variable name");
293     if (Var == PQV_Invalid)
294       return new InvalidQuery("unknown variable: '" + VarStr + "'");
295 
296     QueryRef Q;
297     switch (Var) {
298     case PQV_Output:
299       Q = parseSetOutputKind<SetExclusiveOutputQuery>();
300       break;
301     case PQV_BindRoot:
302       Q = parseSetBool(&QuerySession::BindRoot);
303       break;
304     case PQV_PrintMatcher:
305       Q = parseSetBool(&QuerySession::PrintMatcher);
306       break;
307     case PQV_Traversal:
308       Q = parseSetTraversalKind(&QuerySession::TK);
309       break;
310     case PQV_Invalid:
311       llvm_unreachable("Invalid query kind");
312     }
313 
314     return endQuery(Q);
315   }
316   case PQK_Enable:
317   case PQK_Disable: {
318     StringRef VarStr;
319     ParsedQueryVariable Var =
320         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
321             .Case("output", PQV_Output)
322             .Default(PQV_Invalid);
323     if (VarStr.empty())
324       return new InvalidQuery("expected variable name");
325     if (Var == PQV_Invalid)
326       return new InvalidQuery("unknown variable: '" + VarStr + "'");
327 
328     QueryRef Q;
329 
330     if (QKind == PQK_Enable)
331       Q = parseSetOutputKind<EnableOutputQuery>();
332     else if (QKind == PQK_Disable)
333       Q = parseSetOutputKind<DisableOutputQuery>();
334     else
335       llvm_unreachable("Invalid query kind");
336     return endQuery(Q);
337   }
338 
339   case PQK_Unlet: {
340     StringRef Name = lexWord();
341 
342     if (Name.empty())
343       return new InvalidQuery("expected variable name");
344 
345     return endQuery(new LetQuery(Name, VariantValue()));
346   }
347 
348   case PQK_Invalid:
349     return new InvalidQuery("unknown command: " + CommandStr);
350   }
351 
352   llvm_unreachable("Invalid query kind");
353 }
354 
355 QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
356   return QueryParser(Line, QS).doParse();
357 }
358 
359 std::vector<LineEditor::Completion>
360 QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
361   QueryParser P(Line, QS);
362   P.CompletionPos = Line.data() + Pos;
363 
364   P.doParse();
365   return P.Completions;
366 }
367 
368 } // namespace query
369 } // namespace clang
370