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.ltrim();
30 
31   if (Line.empty())
32     // Even though the Line is empty, it contains a pointer and
33     // a (zero) length. The pointer is used in the LexOrCompleteWord
34     // code completion.
35     return Line;
36 
37   if (Line.front() == '#') {
38     Line = {};
39     return StringRef();
40   }
41 
42   StringRef Word = Line.take_until(isWhitespace);
43   Line = Line.drop_front(Word.size());
44   return Word;
45 }
46 
47 // This is the StringSwitch-alike used by lexOrCompleteWord below. See that
48 // function for details.
49 template <typename T> struct QueryParser::LexOrCompleteWord {
50   StringRef Word;
51   StringSwitch<T> Switch;
52 
53   QueryParser *P;
54   // Set to the completion point offset in Word, or StringRef::npos if
55   // completion point not in Word.
56   size_t WordCompletionPos;
57 
58   // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
59   // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
60   // completions if the lexed word contains the completion point.
61   LexOrCompleteWord(QueryParser *P, StringRef &OutWord)
62       : Word(P->lexWord()), Switch(Word), P(P),
63         WordCompletionPos(StringRef::npos) {
64     OutWord = Word;
65     if (P->CompletionPos && P->CompletionPos <= Word.data() + Word.size()) {
66       if (P->CompletionPos < Word.data())
67         WordCompletionPos = 0;
68       else
69         WordCompletionPos = P->CompletionPos - Word.data();
70     }
71   }
72 
73   LexOrCompleteWord &Case(llvm::StringLiteral CaseStr, const T &Value,
74                           bool IsCompletion = true) {
75 
76     if (WordCompletionPos == StringRef::npos)
77       Switch.Case(CaseStr, Value);
78     else if (CaseStr.size() != 0 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
79              CaseStr.substr(0, WordCompletionPos) ==
80                  Word.substr(0, WordCompletionPos))
81       P->Completions.push_back(LineEditor::Completion(
82           (CaseStr.substr(WordCompletionPos) + " ").str(), CaseStr));
83     return *this;
84   }
85 
86   T Default(T Value) { return Switch.Default(Value); }
87 };
88 
89 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
90   StringRef ValStr;
91   unsigned Value = LexOrCompleteWord<unsigned>(this, ValStr)
92                        .Case("false", 0)
93                        .Case("true", 1)
94                        .Default(~0u);
95   if (Value == ~0u) {
96     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
97   }
98   return new SetQuery<bool>(Var, Value);
99 }
100 
101 template <typename QueryType> QueryRef QueryParser::parseSetOutputKind() {
102   StringRef ValStr;
103   unsigned OutKind = LexOrCompleteWord<unsigned>(this, ValStr)
104                          .Case("diag", OK_Diag)
105                          .Case("print", OK_Print)
106                          .Case("detailed-ast", OK_DetailedAST)
107                          .Case("dump", OK_DetailedAST)
108                          .Default(~0u);
109   if (OutKind == ~0u) {
110     return new InvalidQuery(
111         "expected 'diag', 'print', 'detailed-ast' or 'dump', got '" + ValStr +
112         "'");
113   }
114 
115   switch (OutKind) {
116   case OK_DetailedAST:
117     return new QueryType(&QuerySession::DetailedASTOutput);
118   case OK_Diag:
119     return new QueryType(&QuerySession::DiagOutput);
120   case OK_Print:
121     return new QueryType(&QuerySession::PrintOutput);
122   }
123 
124   llvm_unreachable("Invalid output kind");
125 }
126 
127 QueryRef QueryParser::endQuery(QueryRef Q) {
128   const StringRef Extra = Line;
129   if (!lexWord().empty())
130     return new InvalidQuery("unexpected extra input: '" + Extra + "'");
131   return Q;
132 }
133 
134 namespace {
135 
136 enum ParsedQueryKind {
137   PQK_Invalid,
138   PQK_Comment,
139   PQK_NoOp,
140   PQK_Help,
141   PQK_Let,
142   PQK_Match,
143   PQK_Set,
144   PQK_Unlet,
145   PQK_Quit,
146   PQK_Enable,
147   PQK_Disable
148 };
149 
150 enum ParsedQueryVariable {
151   PQV_Invalid,
152   PQV_Output,
153   PQV_BindRoot,
154   PQV_PrintMatcher
155 };
156 
157 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
158   std::string ErrStr;
159   llvm::raw_string_ostream OS(ErrStr);
160   Diag.printToStreamFull(OS);
161   return new InvalidQuery(OS.str());
162 }
163 
164 } // namespace
165 
166 QueryRef QueryParser::completeMatcherExpression() {
167   std::vector<MatcherCompletion> Comps = Parser::completeExpression(
168       Line, CompletionPos - Line.begin(), nullptr, &QS.NamedValues);
169   for (auto I = Comps.begin(), E = Comps.end(); 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>(this, CommandStr)
178                               .Case("", PQK_NoOp)
179                               .Case("#", PQK_Comment, /*IsCompletion=*/false)
180                               .Case("help", PQK_Help)
181                               .Case("l", PQK_Let, /*IsCompletion=*/false)
182                               .Case("let", PQK_Let)
183                               .Case("m", PQK_Match, /*IsCompletion=*/false)
184                               .Case("match", PQK_Match)
185                               .Case("q", PQK_Quit,  /*IsCompletion=*/false)
186                               .Case("quit", PQK_Quit)
187                               .Case("set", PQK_Set)
188                               .Case("enable", PQK_Enable)
189                               .Case("disable", PQK_Disable)
190                               .Case("unlet", PQK_Unlet)
191                               .Default(PQK_Invalid);
192 
193   switch (QKind) {
194   case PQK_Comment:
195   case PQK_NoOp:
196     return new NoOpQuery;
197 
198   case PQK_Help:
199     return endQuery(new HelpQuery);
200 
201   case PQK_Quit:
202     return endQuery(new QuitQuery);
203 
204   case PQK_Let: {
205     StringRef Name = lexWord();
206 
207     if (Name.empty())
208       return new InvalidQuery("expected variable name");
209 
210     if (CompletionPos)
211       return completeMatcherExpression();
212 
213     Diagnostics Diag;
214     ast_matchers::dynamic::VariantValue Value;
215     if (!Parser::parseExpression(Line, nullptr, &QS.NamedValues, &Value,
216                                  &Diag)) {
217       return makeInvalidQueryFromDiagnostics(Diag);
218     }
219 
220     return new LetQuery(Name, Value);
221   }
222 
223   case PQK_Match: {
224     if (CompletionPos)
225       return completeMatcherExpression();
226 
227     Diagnostics Diag;
228     auto MatcherSource = Line.trim();
229     Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
230         MatcherSource, nullptr, &QS.NamedValues, &Diag);
231     if (!Matcher) {
232       return makeInvalidQueryFromDiagnostics(Diag);
233     }
234     return new MatchQuery(MatcherSource, *Matcher);
235   }
236 
237   case PQK_Set: {
238     StringRef VarStr;
239     ParsedQueryVariable Var =
240         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
241             .Case("output", PQV_Output)
242             .Case("bind-root", PQV_BindRoot)
243             .Case("print-matcher", PQV_PrintMatcher)
244             .Default(PQV_Invalid);
245     if (VarStr.empty())
246       return new InvalidQuery("expected variable name");
247     if (Var == PQV_Invalid)
248       return new InvalidQuery("unknown variable: '" + VarStr + "'");
249 
250     QueryRef Q;
251     switch (Var) {
252     case PQV_Output:
253       Q = parseSetOutputKind<SetExclusiveOutputQuery>();
254       break;
255     case PQV_BindRoot:
256       Q = parseSetBool(&QuerySession::BindRoot);
257       break;
258     case PQV_PrintMatcher:
259       Q = parseSetBool(&QuerySession::PrintMatcher);
260       break;
261     case PQV_Invalid:
262       llvm_unreachable("Invalid query kind");
263     }
264 
265     return endQuery(Q);
266   }
267   case PQK_Enable:
268   case PQK_Disable: {
269     StringRef VarStr;
270     ParsedQueryVariable Var =
271         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
272             .Case("output", PQV_Output)
273             .Default(PQV_Invalid);
274     if (VarStr.empty())
275       return new InvalidQuery("expected variable name");
276     if (Var == PQV_Invalid)
277       return new InvalidQuery("unknown variable: '" + VarStr + "'");
278 
279     QueryRef Q;
280 
281     if (QKind == PQK_Enable)
282       Q = parseSetOutputKind<EnableOutputQuery>();
283     else if (QKind == PQK_Disable)
284       Q = parseSetOutputKind<DisableOutputQuery>();
285     else
286       llvm_unreachable("Invalid query kind");
287     return endQuery(Q);
288   }
289 
290   case PQK_Unlet: {
291     StringRef Name = lexWord();
292 
293     if (Name.empty())
294       return new InvalidQuery("expected variable name");
295 
296     return endQuery(new LetQuery(Name, VariantValue()));
297   }
298 
299   case PQK_Invalid:
300     return new InvalidQuery("unknown command: " + CommandStr);
301   }
302 
303   llvm_unreachable("Invalid query kind");
304 }
305 
306 QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
307   return QueryParser(Line, QS).doParse();
308 }
309 
310 std::vector<LineEditor::Completion>
311 QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
312   QueryParser P(Line, QS);
313   P.CompletionPos = Line.data() + Pos;
314 
315   P.doParse();
316   return P.Completions;
317 }
318 
319 } // namespace query
320 } // namespace clang
321