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 { return Switch.Default(Value); }
80 };
81 
82 // Lexes a word and stores it in Word. Returns a LexOrCompleteWord<T> object
83 // that can be used like a llvm::StringSwitch<T>, but adds cases as possible
84 // completions if the lexed word contains the completion point.
85 template <typename T>
86 QueryParser::LexOrCompleteWord<T>
87 QueryParser::lexOrCompleteWord(StringRef &Word) {
88   Word = lexWord();
89   size_t WordCompletionPos = StringRef::npos;
90   if (CompletionPos && CompletionPos <= Word.data() + Word.size()) {
91     if (CompletionPos < Word.data())
92       WordCompletionPos = 0;
93     else
94       WordCompletionPos = CompletionPos - Word.data();
95   }
96   return LexOrCompleteWord<T>(this, Word, WordCompletionPos);
97 }
98 
99 QueryRef QueryParser::parseSetBool(bool QuerySession::*Var) {
100   StringRef ValStr;
101   unsigned Value = lexOrCompleteWord<unsigned>(ValStr)
102                        .Case("false", 0)
103                        .Case("true", 1)
104                        .Default(~0u);
105   if (Value == ~0u) {
106     return new InvalidQuery("expected 'true' or 'false', got '" + ValStr + "'");
107   }
108   return new SetQuery<bool>(Var, Value);
109 }
110 
111 QueryRef QueryParser::parseSetOutputKind() {
112   StringRef ValStr;
113   unsigned OutKind = lexOrCompleteWord<unsigned>(ValStr)
114                          .Case("diag", OK_Diag)
115                          .Case("print", OK_Print)
116                          .Case("dump", OK_Dump)
117                          .Default(~0u);
118   if (OutKind == ~0u) {
119     return new InvalidQuery("expected 'diag', 'print' or 'dump', got '" +
120                             ValStr + "'");
121   }
122   return new SetQuery<OutputKind>(&QuerySession::OutKind, OutputKind(OutKind));
123 }
124 
125 QueryRef QueryParser::endQuery(QueryRef Q) {
126   const char *Extra = Begin;
127   if (!lexWord().empty())
128     return new InvalidQuery("unexpected extra input: '" +
129                             StringRef(Extra, End - Extra) + "'");
130   return Q;
131 }
132 
133 namespace {
134 
135 enum ParsedQueryKind {
136   PQK_Invalid,
137   PQK_NoOp,
138   PQK_Help,
139   PQK_Let,
140   PQK_Match,
141   PQK_Set,
142   PQK_Unlet,
143   PQK_Quit
144 };
145 
146 enum ParsedQueryVariable { PQV_Invalid, PQV_Output, PQV_BindRoot };
147 
148 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
149   std::string ErrStr;
150   llvm::raw_string_ostream OS(ErrStr);
151   Diag.printToStreamFull(OS);
152   return new InvalidQuery(OS.str());
153 }
154 
155 } // namespace
156 
157 QueryRef QueryParser::completeMatcherExpression() {
158   std::vector<MatcherCompletion> Comps = Parser::completeExpression(
159       StringRef(Begin, End - Begin), CompletionPos - Begin, nullptr,
160       &QS.NamedValues);
161   for (std::vector<MatcherCompletion>::iterator I = Comps.begin(),
162                                                 E = Comps.end();
163        I != E; ++I) {
164     Completions.push_back(LineEditor::Completion(I->TypedText, I->MatcherDecl));
165   }
166   return QueryRef();
167 }
168 
169 QueryRef QueryParser::doParse() {
170   StringRef CommandStr;
171   ParsedQueryKind QKind = lexOrCompleteWord<ParsedQueryKind>(CommandStr)
172                               .Case("", PQK_NoOp)
173                               .Case("help", PQK_Help)
174                               .Case("m", PQK_Match, /*IsCompletion=*/false)
175                               .Case("let", PQK_Let)
176                               .Case("match", PQK_Match)
177                               .Case("set", PQK_Set)
178                               .Case("unlet", PQK_Unlet)
179                               .Case("quit", PQK_Quit)
180                               .Default(PQK_Invalid);
181 
182   switch (QKind) {
183   case PQK_NoOp:
184     return new NoOpQuery;
185 
186   case PQK_Help:
187     return endQuery(new HelpQuery);
188 
189   case PQK_Quit:
190     return endQuery(new QuitQuery);
191 
192   case PQK_Let: {
193     StringRef Name = lexWord();
194 
195     if (Name.empty())
196       return new InvalidQuery("expected variable name");
197 
198     if (CompletionPos)
199       return completeMatcherExpression();
200 
201     Diagnostics Diag;
202     ast_matchers::dynamic::VariantValue Value;
203     if (!Parser::parseExpression(StringRef(Begin, End - Begin), nullptr,
204                                  &QS.NamedValues, &Value, &Diag)) {
205       return makeInvalidQueryFromDiagnostics(Diag);
206     }
207 
208     return new LetQuery(Name, Value);
209   }
210 
211   case PQK_Match: {
212     if (CompletionPos)
213       return completeMatcherExpression();
214 
215     Diagnostics Diag;
216     Optional<DynTypedMatcher> Matcher = Parser::parseMatcherExpression(
217         StringRef(Begin, End - Begin), nullptr, &QS.NamedValues, &Diag);
218     if (!Matcher) {
219       return makeInvalidQueryFromDiagnostics(Diag);
220     }
221     return new MatchQuery(*Matcher);
222   }
223 
224   case PQK_Set: {
225     StringRef VarStr;
226     ParsedQueryVariable Var = lexOrCompleteWord<ParsedQueryVariable>(VarStr)
227                                   .Case("output", PQV_Output)
228                                   .Case("bind-root", PQV_BindRoot)
229                                   .Default(PQV_Invalid);
230     if (VarStr.empty())
231       return new InvalidQuery("expected variable name");
232     if (Var == PQV_Invalid)
233       return new InvalidQuery("unknown variable: '" + VarStr + "'");
234 
235     QueryRef Q;
236     switch (Var) {
237     case PQV_Output:
238       Q = parseSetOutputKind();
239       break;
240     case PQV_BindRoot:
241       Q = parseSetBool(&QuerySession::BindRoot);
242       break;
243     case PQV_Invalid:
244       llvm_unreachable("Invalid query kind");
245     }
246 
247     return endQuery(Q);
248   }
249 
250   case PQK_Unlet: {
251     StringRef Name = lexWord();
252 
253     if (Name.empty())
254       return new InvalidQuery("expected variable name");
255 
256     return endQuery(new LetQuery(Name, VariantValue()));
257   }
258 
259   case PQK_Invalid:
260     return new InvalidQuery("unknown command: " + CommandStr);
261   }
262 
263   llvm_unreachable("Invalid query kind");
264 }
265 
266 QueryRef QueryParser::parse(StringRef Line, const QuerySession &QS) {
267   return QueryParser(Line, QS).doParse();
268 }
269 
270 std::vector<LineEditor::Completion>
271 QueryParser::complete(StringRef Line, size_t Pos, const QuerySession &QS) {
272   QueryParser P(Line, QS);
273   P.CompletionPos = Line.data() + Pos;
274 
275   P.doParse();
276   return P.Completions;
277 }
278 
279 } // namespace query
280 } // namespace clang
281