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 "clang/Tooling/NodeIntrospection.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   Line = Line.drop_while([](char c) {
31     // Don't trim newlines.
32     return StringRef(" \t\v\f\r").contains(c);
33   });
34 
35   if (Line.empty())
36     // Even though the Line is empty, it contains a pointer and
37     // a (zero) length. The pointer is used in the LexOrCompleteWord
38     // code completion.
39     return Line;
40 
41   StringRef Word;
42   if (Line.front() == '#')
43     Word = Line.substr(0, 1);
44   else
45     Word = Line.take_until(isWhitespace);
46 
47   Line = Line.drop_front(Word.size());
48   return Word;
49 }
50 
51 // This is the StringSwitch-alike used by lexOrCompleteWord below. See that
52 // function for details.
53 template <typename T> struct QueryParser::LexOrCompleteWord {
54   StringRef Word;
55   StringSwitch<T> Switch;
56 
57   QueryParser *P;
58   // Set to the completion point offset in Word, or StringRef::npos if
59   // completion point not in Word.
60   size_t WordCompletionPos;
61 
62   // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
63   // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
64   // completions if the lexed word contains the completion point.
65   LexOrCompleteWord(QueryParser *P, StringRef &OutWord)
66       : Word(P->lexWord()), Switch(Word), P(P),
67         WordCompletionPos(StringRef::npos) {
68     OutWord = Word;
69     if (P->CompletionPos && P->CompletionPos <= Word.data() + Word.size()) {
70       if (P->CompletionPos < Word.data())
71         WordCompletionPos = 0;
72       else
73         WordCompletionPos = P->CompletionPos - Word.data();
74     }
75   }
76 
77   LexOrCompleteWord &Case(llvm::StringLiteral CaseStr, const T &Value,
78                           bool IsCompletion = true) {
79 
80     if (WordCompletionPos == StringRef::npos)
81       Switch.Case(CaseStr, Value);
82     else if (CaseStr.size() != 0 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
83              CaseStr.substr(0, WordCompletionPos) ==
84                  Word.substr(0, WordCompletionPos))
85       P->Completions.push_back(LineEditor::Completion(
86           (CaseStr.substr(WordCompletionPos) + " ").str(),
87           std::string(CaseStr)));
88     return *this;
89   }
90 
91   T Default(T Value) { return Switch.Default(Value); }
92 };
93 
94 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
95   StringRef ValStr;
96   unsigned Value = LexOrCompleteWord<unsigned>(this, ValStr)
97                        .Case("false", 0)
98                        .Case("true", 1)
99                        .Default(~0u);
100   if (Value == ~0u) {
101     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
102   }
103   return new SetQuery<bool>(Var, Value);
104 }
105 
106 template <typename QueryType> QueryRef QueryParser::parseSetOutputKind() {
107   StringRef ValStr;
108   bool HasIntrospection = tooling::NodeIntrospection::hasIntrospectionSupport();
109   unsigned OutKind =
110       LexOrCompleteWord<unsigned>(this, ValStr)
111           .Case("diag", OK_Diag)
112           .Case("print", OK_Print)
113           .Case("detailed-ast", OK_DetailedAST)
114           .Case("srcloc", OK_SrcLoc, /*IsCompletion=*/HasIntrospection)
115           .Case("dump", OK_DetailedAST)
116           .Default(~0u);
117   if (OutKind == ~0u) {
118     return new InvalidQuery("expected 'diag', 'print', 'detailed-ast'" +
119                             StringRef(HasIntrospection ? ", 'srcloc'" : "") +
120                             " or 'dump', got '" + ValStr + "'");
121   }
122 
123   switch (OutKind) {
124   case OK_DetailedAST:
125     return new QueryType(&QuerySession::DetailedASTOutput);
126   case OK_Diag:
127     return new QueryType(&QuerySession::DiagOutput);
128   case OK_Print:
129     return new QueryType(&QuerySession::PrintOutput);
130   case OK_SrcLoc:
131     if (HasIntrospection)
132       return new QueryType(&QuerySession::SrcLocOutput);
133     return new InvalidQuery("'srcloc' output support is not available.");
134   }
135 
136   llvm_unreachable("Invalid output kind");
137 }
138 
139 QueryRef QueryParser::parseSetTraversalKind(TraversalKind QuerySession::*Var) {
140   StringRef ValStr;
141   unsigned Value =
142       LexOrCompleteWord<unsigned>(this, ValStr)
143           .Case("AsIs", TK_AsIs)
144           .Case("IgnoreUnlessSpelledInSource", TK_IgnoreUnlessSpelledInSource)
145           .Default(~0u);
146   if (Value == ~0u) {
147     return new InvalidQuery("expected traversal kind, got '" + ValStr + "'");
148   }
149   return new SetQuery<TraversalKind>(Var, static_cast<TraversalKind>(Value));
150 }
151 
152 QueryRef QueryParser::endQuery(QueryRef Q) {
153   StringRef Extra = Line;
154   StringRef ExtraTrimmed = Extra.drop_while(
155       [](char c) { return StringRef(" \t\v\f\r").contains(c); });
156 
157   if ((!ExtraTrimmed.empty() && ExtraTrimmed[0] == '\n') ||
158       (ExtraTrimmed.size() >= 2 && ExtraTrimmed[0] == '\r' &&
159        ExtraTrimmed[1] == '\n'))
160     Q->RemainingContent = Extra;
161   else {
162     StringRef TrailingWord = lexWord();
163     if (!TrailingWord.empty() && TrailingWord.front() == '#') {
164       Line = Line.drop_until([](char c) { return c == '\n'; });
165       Line = Line.drop_while([](char c) { return c == '\n'; });
166       return endQuery(Q);
167     }
168     if (!TrailingWord.empty()) {
169       return new InvalidQuery("unexpected extra input: '" + Extra + "'");
170     }
171   }
172   return Q;
173 }
174 
175 namespace {
176 
177 enum ParsedQueryKind {
178   PQK_Invalid,
179   PQK_Comment,
180   PQK_NoOp,
181   PQK_Help,
182   PQK_Let,
183   PQK_Match,
184   PQK_Set,
185   PQK_Unlet,
186   PQK_Quit,
187   PQK_Enable,
188   PQK_Disable
189 };
190 
191 enum ParsedQueryVariable {
192   PQV_Invalid,
193   PQV_Output,
194   PQV_BindRoot,
195   PQV_PrintMatcher,
196   PQV_Traversal
197 };
198 
199 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
200   std::string ErrStr;
201   llvm::raw_string_ostream OS(ErrStr);
202   Diag.printToStreamFull(OS);
203   return new InvalidQuery(OS.str());
204 }
205 
206 } // namespace
207 
208 QueryRef QueryParser::completeMatcherExpression() {
209   std::vector<MatcherCompletion> Comps = Parser::completeExpression(
210       Line, CompletionPos - Line.begin(), nullptr, &QS.NamedValues);
211   for (auto I = Comps.begin(), E = Comps.end(); I != E; ++I) {
212     Completions.push_back(LineEditor::Completion(I->TypedText, I->MatcherDecl));
213   }
214   return QueryRef();
215 }
216 
217 QueryRef QueryParser::doParse() {
218   StringRef CommandStr;
219   ParsedQueryKind QKind = LexOrCompleteWord<ParsedQueryKind>(this, CommandStr)
220                               .Case("", PQK_NoOp)
221                               .Case("#", PQK_Comment, /*IsCompletion=*/false)
222                               .Case("help", PQK_Help)
223                               .Case("l", PQK_Let, /*IsCompletion=*/false)
224                               .Case("let", PQK_Let)
225                               .Case("m", PQK_Match, /*IsCompletion=*/false)
226                               .Case("match", PQK_Match)
227                               .Case("q", PQK_Quit,  /*IsCompletion=*/false)
228                               .Case("quit", PQK_Quit)
229                               .Case("set", PQK_Set)
230                               .Case("enable", PQK_Enable)
231                               .Case("disable", PQK_Disable)
232                               .Case("unlet", PQK_Unlet)
233                               .Default(PQK_Invalid);
234 
235   switch (QKind) {
236   case PQK_Comment:
237   case PQK_NoOp:
238     Line = Line.drop_until([](char c) { return c == '\n'; });
239     Line = Line.drop_while([](char c) { return c == '\n'; });
240     if (Line.empty())
241       return new NoOpQuery;
242     return doParse();
243 
244   case PQK_Help:
245     return endQuery(new HelpQuery);
246 
247   case PQK_Quit:
248     return endQuery(new QuitQuery);
249 
250   case PQK_Let: {
251     StringRef Name = lexWord();
252 
253     if (Name.empty())
254       return new InvalidQuery("expected variable name");
255 
256     if (CompletionPos)
257       return completeMatcherExpression();
258 
259     Diagnostics Diag;
260     ast_matchers::dynamic::VariantValue Value;
261     if (!Parser::parseExpression(Line, nullptr, &QS.NamedValues, &Value,
262                                  &Diag)) {
263       return makeInvalidQueryFromDiagnostics(Diag);
264     }
265 
266     auto *Q = new LetQuery(Name, Value);
267     Q->RemainingContent = Line;
268     return Q;
269   }
270 
271   case PQK_Match: {
272     if (CompletionPos)
273       return completeMatcherExpression();
274 
275     Diagnostics Diag;
276     auto MatcherSource = Line.ltrim();
277     auto OrigMatcherSource = MatcherSource;
278     Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
279         MatcherSource, nullptr, &QS.NamedValues, &Diag);
280     if (!Matcher) {
281       return makeInvalidQueryFromDiagnostics(Diag);
282     }
283     auto ActualSource = OrigMatcherSource.slice(0, OrigMatcherSource.size() -
284                                                        MatcherSource.size());
285     auto *Q = new MatchQuery(ActualSource, *Matcher);
286     Q->RemainingContent = MatcherSource;
287     return Q;
288   }
289 
290   case PQK_Set: {
291     StringRef VarStr;
292     ParsedQueryVariable Var =
293         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
294             .Case("output", PQV_Output)
295             .Case("bind-root", PQV_BindRoot)
296             .Case("print-matcher", PQV_PrintMatcher)
297             .Case("traversal", PQV_Traversal)
298             .Default(PQV_Invalid);
299     if (VarStr.empty())
300       return new InvalidQuery("expected variable name");
301     if (Var == PQV_Invalid)
302       return new InvalidQuery("unknown variable: '" + VarStr + "'");
303 
304     QueryRef Q;
305     switch (Var) {
306     case PQV_Output:
307       Q = parseSetOutputKind<SetExclusiveOutputQuery>();
308       break;
309     case PQV_BindRoot:
310       Q = parseSetBool(&QuerySession::BindRoot);
311       break;
312     case PQV_PrintMatcher:
313       Q = parseSetBool(&QuerySession::PrintMatcher);
314       break;
315     case PQV_Traversal:
316       Q = parseSetTraversalKind(&QuerySession::TK);
317       break;
318     case PQV_Invalid:
319       llvm_unreachable("Invalid query kind");
320     }
321 
322     return endQuery(Q);
323   }
324   case PQK_Enable:
325   case PQK_Disable: {
326     StringRef VarStr;
327     ParsedQueryVariable Var =
328         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
329             .Case("output", PQV_Output)
330             .Default(PQV_Invalid);
331     if (VarStr.empty())
332       return new InvalidQuery("expected variable name");
333     if (Var == PQV_Invalid)
334       return new InvalidQuery("unknown variable: '" + VarStr + "'");
335 
336     QueryRef Q;
337 
338     if (QKind == PQK_Enable)
339       Q = parseSetOutputKind<EnableOutputQuery>();
340     else if (QKind == PQK_Disable)
341       Q = parseSetOutputKind<DisableOutputQuery>();
342     else
343       llvm_unreachable("Invalid query kind");
344     return endQuery(Q);
345   }
346 
347   case PQK_Unlet: {
348     StringRef Name = lexWord();
349 
350     if (Name.empty())
351       return new InvalidQuery("expected variable name");
352 
353     return endQuery(new LetQuery(Name, VariantValue()));
354   }
355 
356   case PQK_Invalid:
357     return new InvalidQuery("unknown command: " + CommandStr);
358   }
359 
360   llvm_unreachable("Invalid query kind");
361 }
362 
363 QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
364   return QueryParser(Line, QS).doParse();
365 }
366 
367 std::vector<LineEditor::Completion>
368 QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
369   QueryParser P(Line, QS);
370   P.CompletionPos = Line.data() + Pos;
371 
372   P.doParse();
373   return P.Completions;
374 }
375 
376 } // namespace query
377 } // namespace clang
378