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