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   if (*Begin == '#') {
41     End = Begin;
42     return StringRef();
43   }
44 
45   const char *WordBegin = Begin;
46 
47   while (true) {
48     ++Begin;
49 
50     if (Begin == End || isWhitespace(*Begin))
51       return StringRef(WordBegin, Begin - WordBegin);
52   }
53 }
54 
55 // This is the StringSwitch-alike used by lexOrCompleteWord below. See that
56 // function for details.
57 template <typename T> struct QueryParser::LexOrCompleteWord {
58   StringRef Word;
59   StringSwitch<T> Switch;
60 
61   QueryParser *P;
62   // Set to the completion point offset in Word, or StringRef::npos if
63   // completion point not in Word.
64   size_t WordCompletionPos;
65 
66   // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
67   // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
68   // completions if the lexed word contains the completion point.
69   LexOrCompleteWord(QueryParser *P, StringRef &OutWord)
70       : Word(P->lexWord()), Switch(Word), P(P),
71         WordCompletionPos(StringRef::npos) {
72     OutWord = Word;
73     if (P->CompletionPos && P->CompletionPos <= Word.data() + Word.size()) {
74       if (P->CompletionPos < Word.data())
75         WordCompletionPos = 0;
76       else
77         WordCompletionPos = P->CompletionPos - Word.data();
78     }
79   }
80 
81   LexOrCompleteWord &Case(llvm::StringLiteral CaseStr, const T &Value,
82                           bool IsCompletion = true) {
83 
84     if (WordCompletionPos == StringRef::npos)
85       Switch.Case(CaseStr, Value);
86     else if (CaseStr.size() != 0 && IsCompletion && WordCompletionPos <= CaseStr.size() &&
87              CaseStr.substr(0, WordCompletionPos) ==
88                  Word.substr(0, WordCompletionPos))
89       P->Completions.push_back(LineEditor::Completion(
90           (CaseStr.substr(WordCompletionPos) + " ").str(), CaseStr));
91     return *this;
92   }
93 
94   T Default(T Value) { return Switch.Default(Value); }
95 };
96 
97 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
98   StringRef ValStr;
99   unsigned Value = LexOrCompleteWord<unsigned>(this, ValStr)
100                        .Case("false", 0)
101                        .Case("true", 1)
102                        .Default(~0u);
103   if (Value == ~0u) {
104     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
105   }
106   return new SetQuery<bool>(Var, Value);
107 }
108 
109 QueryRef QueryParser::parseSetOutputKind() {
110   StringRef ValStr;
111   unsigned OutKind = LexOrCompleteWord<unsigned>(this, ValStr)
112                          .Case("diag", OK_Diag)
113                          .Case("print", OK_Print)
114                          .Case("detailed-ast", OK_DetailedAST)
115                          .Case("dump", OK_DetailedAST)
116                          .Default(~0u);
117   if (OutKind == ~0u) {
118     return new InvalidQuery(
119         "expected 'diag', 'print', 'detailed-ast' or 'dump', got '" + ValStr +
120         "'");
121   }
122 
123   switch (OutKind) {
124   case OK_DetailedAST:
125     return new SetExclusiveOutputQuery(&QuerySession::DetailedASTOutput);
126   case OK_Diag:
127     return new SetExclusiveOutputQuery(&QuerySession::DiagOutput);
128   case OK_Print:
129     return new SetExclusiveOutputQuery(&QuerySession::PrintOutput);
130   }
131 
132   llvm_unreachable("Invalid output kind");
133 }
134 
135 QueryRef QueryParser::endQuery(QueryRef Q) {
136   const char *Extra = Begin;
137   if (!lexWord().empty())
138     return new InvalidQuery("unexpected extra input: '" +
139                             StringRef(Extra, End - Extra) + "'");
140   return Q;
141 }
142 
143 namespace {
144 
145 enum ParsedQueryKind {
146   PQK_Invalid,
147   PQK_Comment,
148   PQK_NoOp,
149   PQK_Help,
150   PQK_Let,
151   PQK_Match,
152   PQK_Set,
153   PQK_Unlet,
154   PQK_Quit
155 };
156 
157 enum ParsedQueryVariable {
158   PQV_Invalid,
159   PQV_Output,
160   PQV_BindRoot,
161   PQV_PrintMatcher
162 };
163 
164 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
165   std::string ErrStr;
166   llvm::raw_string_ostream OS(ErrStr);
167   Diag.printToStreamFull(OS);
168   return new InvalidQuery(OS.str());
169 }
170 
171 } // namespace
172 
173 QueryRef QueryParser::completeMatcherExpression() {
174   std::vector<MatcherCompletion> Comps = Parser::completeExpression(
175       StringRef(Begin, End - Begin), CompletionPos - Begin, nullptr,
176       &QS.NamedValues);
177   for (auto I = Comps.begin(), E = Comps.end(); I != E; ++I) {
178     Completions.push_back(LineEditor::Completion(I->TypedText, I->MatcherDecl));
179   }
180   return QueryRef();
181 }
182 
183 QueryRef QueryParser::doParse() {
184   StringRef CommandStr;
185   ParsedQueryKind QKind = LexOrCompleteWord<ParsedQueryKind>(this, CommandStr)
186                               .Case("", PQK_NoOp)
187                               .Case("#", PQK_Comment, /*IsCompletion=*/false)
188                               .Case("help", PQK_Help)
189                               .Case("l", PQK_Let, /*IsCompletion=*/false)
190                               .Case("let", PQK_Let)
191                               .Case("m", PQK_Match, /*IsCompletion=*/false)
192                               .Case("match", PQK_Match)
193                               .Case("q", PQK_Quit,  /*IsCompletion=*/false)
194                               .Case("quit", PQK_Quit)
195                               .Case("set", PQK_Set)
196                               .Case("unlet", PQK_Unlet)
197                               .Default(PQK_Invalid);
198 
199   switch (QKind) {
200   case PQK_Comment:
201   case PQK_NoOp:
202     return new NoOpQuery;
203 
204   case PQK_Help:
205     return endQuery(new HelpQuery);
206 
207   case PQK_Quit:
208     return endQuery(new QuitQuery);
209 
210   case PQK_Let: {
211     StringRef Name = lexWord();
212 
213     if (Name.empty())
214       return new InvalidQuery("expected variable name");
215 
216     if (CompletionPos)
217       return completeMatcherExpression();
218 
219     Diagnostics Diag;
220     ast_matchers::dynamic::VariantValue Value;
221     if (!Parser::parseExpression(StringRef(Begin, End - Begin), nullptr,
222                                  &QS.NamedValues, &Value, &Diag)) {
223       return makeInvalidQueryFromDiagnostics(Diag);
224     }
225 
226     return new LetQuery(Name, Value);
227   }
228 
229   case PQK_Match: {
230     if (CompletionPos)
231       return completeMatcherExpression();
232 
233     Diagnostics Diag;
234     auto MatcherSource = StringRef(Begin, End - Begin).trim();
235     Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
236         MatcherSource, nullptr, &QS.NamedValues, &Diag);
237     if (!Matcher) {
238       return makeInvalidQueryFromDiagnostics(Diag);
239     }
240     return new MatchQuery(MatcherSource, *Matcher);
241   }
242 
243   case PQK_Set: {
244     StringRef VarStr;
245     ParsedQueryVariable Var =
246         LexOrCompleteWord<ParsedQueryVariable>(this, VarStr)
247             .Case("output", PQV_Output)
248             .Case("bind-root", PQV_BindRoot)
249             .Case("print-matcher", PQV_PrintMatcher)
250             .Default(PQV_Invalid);
251     if (VarStr.empty())
252       return new InvalidQuery("expected variable name");
253     if (Var == PQV_Invalid)
254       return new InvalidQuery("unknown variable: '" + VarStr + "'");
255 
256     QueryRef Q;
257     switch (Var) {
258     case PQV_Output:
259       Q = parseSetOutputKind();
260       break;
261     case PQV_BindRoot:
262       Q = parseSetBool(&QuerySession::BindRoot);
263       break;
264     case PQV_PrintMatcher:
265       Q = parseSetBool(&QuerySession::PrintMatcher);
266       break;
267     case PQV_Invalid:
268       llvm_unreachable("Invalid query kind");
269     }
270 
271     return endQuery(Q);
272   }
273 
274   case PQK_Unlet: {
275     StringRef Name = lexWord();
276 
277     if (Name.empty())
278       return new InvalidQuery("expected variable name");
279 
280     return endQuery(new LetQuery(Name, VariantValue()));
281   }
282 
283   case PQK_Invalid:
284     return new InvalidQuery("unknown command: " + CommandStr);
285   }
286 
287   llvm_unreachable("Invalid query kind");
288 }
289 
290 QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
291   return QueryParser(Line, QS).doParse();
292 }
293 
294 std::vector<LineEditor::Completion>
295 QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
296   QueryParser P(Line, QS);
297   P.CompletionPos = Line.data() + Pos;
298 
299   P.doParse();
300   return P.Completions;
301 }
302 
303 } // namespace query
304 } // namespace clang
305