1 //===- OptTable.h - Option Table --------------------------------*- C++ -*-===//
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 #ifndef LLVM_OPTION_OPTTABLE_H
10 #define LLVM_OPTION_OPTTABLE_H
11 
12 #include "llvm/ADT/ArrayRef.h"
13 #include "llvm/ADT/SmallString.h"
14 #include "llvm/ADT/StringRef.h"
15 #include "llvm/Option/OptSpecifier.h"
16 #include "llvm/Support/StringSaver.h"
17 #include <cassert>
18 #include <string>
19 #include <vector>
20 
21 namespace llvm {
22 
23 class raw_ostream;
24 template <typename Fn> class function_ref;
25 
26 namespace opt {
27 
28 class Arg;
29 class ArgList;
30 class InputArgList;
31 class Option;
32 
33 /// Provide access to the Option info table.
34 ///
35 /// The OptTable class provides a layer of indirection which allows Option
36 /// instance to be created lazily. In the common case, only a few options will
37 /// be needed at runtime; the OptTable class maintains enough information to
38 /// parse command lines without instantiating Options, while letting other
39 /// parts of the driver still use Option instances where convenient.
40 class OptTable {
41 public:
42   /// Entry for a single option instance in the option data table.
43   struct Info {
44     /// A null terminated array of prefix strings to apply to name while
45     /// matching.
46     ArrayRef<StringLiteral> Prefixes;
47     StringRef Name;
48     const char *HelpText;
49     const char *MetaVar;
50     unsigned ID;
51     unsigned char Kind;
52     unsigned char Param;
53     unsigned int Flags;
54     unsigned short GroupID;
55     unsigned short AliasID;
56     const char *AliasArgs;
57     const char *Values;
58   };
59 
60 private:
61   /// The option information table.
62   ArrayRef<Info> OptionInfos;
63   bool IgnoreCase;
64   bool GroupedShortOptions = false;
65   bool DashDashParsing = false;
66   const char *EnvVar = nullptr;
67 
68   unsigned InputOptionID = 0;
69   unsigned UnknownOptionID = 0;
70 
71 protected:
72   /// The index of the first option which can be parsed (i.e., is not a
73   /// special option like 'input' or 'unknown', and is not an option group).
74   unsigned FirstSearchableIndex = 0;
75 
76   /// The union of the first element of all option prefixes.
77   SmallString<8> PrefixChars;
78 
79   /// The union of all option prefixes. If an argument does not begin with
80   /// one of these, it is an input.
81   virtual ArrayRef<StringLiteral> getPrefixesUnion() const = 0;
82 
83 private:
84   const Info &getInfo(OptSpecifier Opt) const {
85     unsigned id = Opt.getID();
86     assert(id > 0 && id - 1 < getNumOptions() && "Invalid Option ID.");
87     return OptionInfos[id - 1];
88   }
89 
90   std::unique_ptr<Arg> parseOneArgGrouped(InputArgList &Args,
91                                           unsigned &Index) const;
92 
93 protected:
94   /// Initialize OptTable using Tablegen'ed OptionInfos. Child class must
95   /// manually call \c buildPrefixChars once they are fully constructed.
96   OptTable(ArrayRef<Info> OptionInfos, bool IgnoreCase = false);
97 
98   /// Build (or rebuild) the PrefixChars member.
99   void buildPrefixChars();
100 
101 public:
102   virtual ~OptTable();
103 
104   /// Return the total number of option classes.
105   unsigned getNumOptions() const { return OptionInfos.size(); }
106 
107   /// Get the given Opt's Option instance, lazily creating it
108   /// if necessary.
109   ///
110   /// \return The option, or null for the INVALID option id.
111   const Option getOption(OptSpecifier Opt) const;
112 
113   /// Lookup the name of the given option.
114   StringRef getOptionName(OptSpecifier id) const { return getInfo(id).Name; }
115 
116   /// Get the kind of the given option.
117   unsigned getOptionKind(OptSpecifier id) const {
118     return getInfo(id).Kind;
119   }
120 
121   /// Get the group id for the given option.
122   unsigned getOptionGroupID(OptSpecifier id) const {
123     return getInfo(id).GroupID;
124   }
125 
126   /// Get the help text to use to describe this option.
127   const char *getOptionHelpText(OptSpecifier id) const {
128     return getInfo(id).HelpText;
129   }
130 
131   /// Get the meta-variable name to use when describing
132   /// this options values in the help text.
133   const char *getOptionMetaVar(OptSpecifier id) const {
134     return getInfo(id).MetaVar;
135   }
136 
137   /// Specify the environment variable where initial options should be read.
138   void setInitialOptionsFromEnvironment(const char *E) { EnvVar = E; }
139 
140   /// Support grouped short options. e.g. -ab represents -a -b.
141   void setGroupedShortOptions(bool Value) { GroupedShortOptions = Value; }
142 
143   /// Set whether "--" stops option parsing and treats all subsequent arguments
144   /// as positional. E.g. -- -a -b gives two positional inputs.
145   void setDashDashParsing(bool Value) { DashDashParsing = Value; }
146 
147   /// Find possible value for given flags. This is used for shell
148   /// autocompletion.
149   ///
150   /// \param [in] Option - Key flag like "-stdlib=" when "-stdlib=l"
151   /// was passed to clang.
152   ///
153   /// \param [in] Arg - Value which we want to autocomplete like "l"
154   /// when "-stdlib=l" was passed to clang.
155   ///
156   /// \return The vector of possible values.
157   std::vector<std::string> suggestValueCompletions(StringRef Option,
158                                                    StringRef Arg) const;
159 
160   /// Find flags from OptTable which starts with Cur.
161   ///
162   /// \param [in] Cur - String prefix that all returned flags need
163   //  to start with.
164   ///
165   /// \return The vector of flags which start with Cur.
166   std::vector<std::string> findByPrefix(StringRef Cur,
167                                         unsigned int DisableFlags) const;
168 
169   /// Find the OptTable option that most closely matches the given string.
170   ///
171   /// \param [in] Option - A string, such as "-stdlibs=l", that represents user
172   /// input of an option that may not exist in the OptTable. Note that the
173   /// string includes prefix dashes "-" as well as values "=l".
174   /// \param [out] NearestString - The nearest option string found in the
175   /// OptTable.
176   /// \param [in] FlagsToInclude - Only find options with any of these flags.
177   /// Zero is the default, which includes all flags.
178   /// \param [in] FlagsToExclude - Don't find options with this flag. Zero
179   /// is the default, and means exclude nothing.
180   /// \param [in] MinimumLength - Don't find options shorter than this length.
181   /// For example, a minimum length of 3 prevents "-x" from being considered
182   /// near to "-S".
183   /// \param [in] MaximumDistance - Don't find options whose distance is greater
184   /// than this value.
185   ///
186   /// \return The edit distance of the nearest string found.
187   unsigned findNearest(StringRef Option, std::string &NearestString,
188                        unsigned FlagsToInclude = 0, unsigned FlagsToExclude = 0,
189                        unsigned MinimumLength = 4,
190                        unsigned MaximumDistance = UINT_MAX) const;
191 
192   bool findExact(StringRef Option, std::string &ExactString,
193                  unsigned FlagsToInclude = 0,
194                  unsigned FlagsToExclude = 0) const {
195     return findNearest(Option, ExactString, FlagsToInclude, FlagsToExclude, 4,
196                        0) == 0;
197   }
198 
199   /// Parse a single argument; returning the new argument and
200   /// updating Index.
201   ///
202   /// \param [in,out] Index - The current parsing position in the argument
203   /// string list; on return this will be the index of the next argument
204   /// string to parse.
205   /// \param [in] FlagsToInclude - Only parse options with any of these flags.
206   /// Zero is the default which includes all flags.
207   /// \param [in] FlagsToExclude - Don't parse options with this flag.  Zero
208   /// is the default and means exclude nothing.
209   ///
210   /// \return The parsed argument, or 0 if the argument is missing values
211   /// (in which case Index still points at the conceptual next argument string
212   /// to parse).
213   std::unique_ptr<Arg> ParseOneArg(const ArgList &Args, unsigned &Index,
214                                    unsigned FlagsToInclude = 0,
215                                    unsigned FlagsToExclude = 0) const;
216 
217   /// Parse an list of arguments into an InputArgList.
218   ///
219   /// The resulting InputArgList will reference the strings in [\p ArgBegin,
220   /// \p ArgEnd), and their lifetime should extend past that of the returned
221   /// InputArgList.
222   ///
223   /// The only error that can occur in this routine is if an argument is
224   /// missing values; in this case \p MissingArgCount will be non-zero.
225   ///
226   /// \param MissingArgIndex - On error, the index of the option which could
227   /// not be parsed.
228   /// \param MissingArgCount - On error, the number of missing options.
229   /// \param FlagsToInclude - Only parse options with any of these flags.
230   /// Zero is the default which includes all flags.
231   /// \param FlagsToExclude - Don't parse options with this flag.  Zero
232   /// is the default and means exclude nothing.
233   /// \return An InputArgList; on error this will contain all the options
234   /// which could be parsed.
235   InputArgList ParseArgs(ArrayRef<const char *> Args, unsigned &MissingArgIndex,
236                          unsigned &MissingArgCount, unsigned FlagsToInclude = 0,
237                          unsigned FlagsToExclude = 0) const;
238 
239   /// A convenience helper which handles optional initial options populated from
240   /// an environment variable, expands response files recursively and parses
241   /// options.
242   ///
243   /// \param ErrorFn - Called on a formatted error message for missing arguments
244   /// or unknown options.
245   /// \return An InputArgList; on error this will contain all the options which
246   /// could be parsed.
247   InputArgList parseArgs(int Argc, char *const *Argv, OptSpecifier Unknown,
248                          StringSaver &Saver,
249                          function_ref<void(StringRef)> ErrorFn) const;
250 
251   /// Render the help text for an option table.
252   ///
253   /// \param OS - The stream to write the help text to.
254   /// \param Usage - USAGE: Usage
255   /// \param Title - OVERVIEW: Title
256   /// \param FlagsToInclude - If non-zero, only include options with any
257   ///                         of these flags set.
258   /// \param FlagsToExclude - Exclude options with any of these flags set.
259   /// \param ShowAllAliases - If true, display all options including aliases
260   ///                         that don't have help texts. By default, we display
261   ///                         only options that are not hidden and have help
262   ///                         texts.
263   void printHelp(raw_ostream &OS, const char *Usage, const char *Title,
264                  unsigned FlagsToInclude, unsigned FlagsToExclude,
265                  bool ShowAllAliases) const;
266 
267   void printHelp(raw_ostream &OS, const char *Usage, const char *Title,
268                  bool ShowHidden = false, bool ShowAllAliases = false) const;
269 };
270 
271 /// Specialization of OptTable
272 class GenericOptTable : public OptTable {
273   SmallVector<StringLiteral> PrefixesUnionBuffer;
274 
275 protected:
276   GenericOptTable(ArrayRef<Info> OptionInfos, bool IgnoreCase = false);
277   ArrayRef<StringLiteral> getPrefixesUnion() const final {
278     return PrefixesUnionBuffer;
279   }
280 };
281 
282 class PrecomputedOptTable : public OptTable {
283   ArrayRef<StringLiteral> PrefixesUnion;
284 
285 protected:
286   PrecomputedOptTable(ArrayRef<Info> OptionInfos,
287                       ArrayRef<StringLiteral> PrefixesTable,
288                       bool IgnoreCase = false)
289       : OptTable(OptionInfos, IgnoreCase), PrefixesUnion(PrefixesTable) {
290     buildPrefixChars();
291   }
292   ArrayRef<StringLiteral> getPrefixesUnion() const final {
293     return PrefixesUnion;
294   }
295 };
296 
297 } // end namespace opt
298 
299 } // end namespace llvm
300 
301 #endif // LLVM_OPTION_OPTTABLE_H
302