1//===- ClangOptionDocEmitter.cpp - Documentation for command line flags ---===//
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// FIXME: Once this has stabilized, consider moving it to LLVM.
8//
9//===----------------------------------------------------------------------===//
10
11#include "TableGenBackends.h"
12#include "llvm/TableGen/Error.h"
13#include "llvm/ADT/STLExtras.h"
14#include "llvm/ADT/SmallString.h"
15#include "llvm/ADT/StringSwitch.h"
16#include "llvm/ADT/Twine.h"
17#include "llvm/TableGen/Record.h"
18#include "llvm/TableGen/TableGenBackend.h"
19#include <cctype>
20#include <cstring>
21#include <map>
22
23using namespace llvm;
24
25namespace {
26struct DocumentedOption {
27  Record *Option;
28  std::vector<Record*> Aliases;
29};
30struct DocumentedGroup;
31struct Documentation {
32  std::vector<DocumentedGroup> Groups;
33  std::vector<DocumentedOption> Options;
34};
35struct DocumentedGroup : Documentation {
36  Record *Group;
37};
38
39// Reorganize the records into a suitable form for emitting documentation.
40Documentation extractDocumentation(RecordKeeper &Records) {
41  Documentation Result;
42
43  // Build the tree of groups. The root in the tree is the fake option group
44  // (Record*)nullptr, which contains all top-level groups and options.
45  std::map<Record*, std::vector<Record*> > OptionsInGroup;
46  std::map<Record*, std::vector<Record*> > GroupsInGroup;
47  std::map<Record*, std::vector<Record*> > Aliases;
48
49  std::map<std::string, Record*> OptionsByName;
50  for (Record *R : Records.getAllDerivedDefinitions("Option"))
51    OptionsByName[std::string(R->getValueAsString("Name"))] = R;
52
53  auto Flatten = [](Record *R) {
54    return R->getValue("DocFlatten") && R->getValueAsBit("DocFlatten");
55  };
56
57  auto SkipFlattened = [&](Record *R) -> Record* {
58    while (R && Flatten(R)) {
59      auto *G = dyn_cast<DefInit>(R->getValueInit("Group"));
60      if (!G)
61        return nullptr;
62      R = G->getDef();
63    }
64    return R;
65  };
66
67  for (Record *R : Records.getAllDerivedDefinitions("OptionGroup")) {
68    if (Flatten(R))
69      continue;
70
71    Record *Group = nullptr;
72    if (auto *G = dyn_cast<DefInit>(R->getValueInit("Group")))
73      Group = SkipFlattened(G->getDef());
74    GroupsInGroup[Group].push_back(R);
75  }
76
77  for (Record *R : Records.getAllDerivedDefinitions("Option")) {
78    if (auto *A = dyn_cast<DefInit>(R->getValueInit("Alias"))) {
79      Aliases[A->getDef()].push_back(R);
80      continue;
81    }
82
83    // Pretend no-X and Xno-Y options are aliases of X and XY.
84    std::string Name = std::string(R->getValueAsString("Name"));
85    if (Name.size() >= 4) {
86      if (Name.substr(0, 3) == "no-" && OptionsByName[Name.substr(3)]) {
87        Aliases[OptionsByName[Name.substr(3)]].push_back(R);
88        continue;
89      }
90      if (Name.substr(1, 3) == "no-" && OptionsByName[Name[0] + Name.substr(4)]) {
91        Aliases[OptionsByName[Name[0] + Name.substr(4)]].push_back(R);
92        continue;
93      }
94    }
95
96    Record *Group = nullptr;
97    if (auto *G = dyn_cast<DefInit>(R->getValueInit("Group")))
98      Group = SkipFlattened(G->getDef());
99    OptionsInGroup[Group].push_back(R);
100  }
101
102  auto CompareByName = [](Record *A, Record *B) {
103    return A->getValueAsString("Name") < B->getValueAsString("Name");
104  };
105
106  auto CompareByLocation = [](Record *A, Record *B) {
107    return A->getLoc()[0].getPointer() < B->getLoc()[0].getPointer();
108  };
109
110  auto DocumentationForOption = [&](Record *R) -> DocumentedOption {
111    auto &A = Aliases[R];
112    llvm::sort(A, CompareByName);
113    return {R, std::move(A)};
114  };
115
116  std::function<Documentation(Record *)> DocumentationForGroup =
117      [&](Record *R) -> Documentation {
118    Documentation D;
119
120    auto &Groups = GroupsInGroup[R];
121    llvm::sort(Groups, CompareByLocation);
122    for (Record *G : Groups) {
123      D.Groups.emplace_back();
124      D.Groups.back().Group = G;
125      Documentation &Base = D.Groups.back();
126      Base = DocumentationForGroup(G);
127    }
128
129    auto &Options = OptionsInGroup[R];
130    llvm::sort(Options, CompareByName);
131    for (Record *O : Options)
132      D.Options.push_back(DocumentationForOption(O));
133
134    return D;
135  };
136
137  return DocumentationForGroup(nullptr);
138}
139
140// Get the first and successive separators to use for an OptionKind.
141std::pair<StringRef,StringRef> getSeparatorsForKind(const Record *OptionKind) {
142  return StringSwitch<std::pair<StringRef, StringRef>>(OptionKind->getName())
143    .Cases("KIND_JOINED", "KIND_JOINED_OR_SEPARATE",
144           "KIND_JOINED_AND_SEPARATE",
145           "KIND_REMAINING_ARGS_JOINED", {"", " "})
146    .Case("KIND_COMMAJOINED", {"", ","})
147    .Default({" ", " "});
148}
149
150const unsigned UnlimitedArgs = unsigned(-1);
151
152// Get the number of arguments expected for an option, or -1 if any number of
153// arguments are accepted.
154unsigned getNumArgsForKind(Record *OptionKind, const Record *Option) {
155  return StringSwitch<unsigned>(OptionKind->getName())
156    .Cases("KIND_JOINED", "KIND_JOINED_OR_SEPARATE", "KIND_SEPARATE", 1)
157    .Cases("KIND_REMAINING_ARGS", "KIND_REMAINING_ARGS_JOINED",
158           "KIND_COMMAJOINED", UnlimitedArgs)
159    .Case("KIND_JOINED_AND_SEPARATE", 2)
160    .Case("KIND_MULTIARG", Option->getValueAsInt("NumArgs"))
161    .Default(0);
162}
163
164bool hasFlag(const Record *OptionOrGroup, StringRef OptionFlag) {
165  for (const Record *Flag : OptionOrGroup->getValueAsListOfDefs("Flags"))
166    if (Flag->getName() == OptionFlag)
167      return true;
168  return false;
169}
170
171bool isExcluded(const Record *OptionOrGroup, const Record *DocInfo) {
172  // FIXME: Provide a flag to specify the set of exclusions.
173  for (StringRef Exclusion : DocInfo->getValueAsListOfStrings("ExcludedFlags"))
174    if (hasFlag(OptionOrGroup, Exclusion))
175      return true;
176  return false;
177}
178
179std::string escapeRST(StringRef Str) {
180  std::string Out;
181  for (auto K : Str) {
182    if (StringRef("`*|_[]\\").count(K))
183      Out.push_back('\\');
184    Out.push_back(K);
185  }
186  return Out;
187}
188
189StringRef getSphinxOptionID(StringRef OptionName) {
190  for (auto I = OptionName.begin(), E = OptionName.end(); I != E; ++I)
191    if (!isalnum(*I) && *I != '-')
192      return OptionName.substr(0, I - OptionName.begin());
193  return OptionName;
194}
195
196bool canSphinxCopeWithOption(const Record *Option) {
197  // HACK: Work arond sphinx's inability to cope with punctuation-only options
198  // such as /? by suppressing them from the option list.
199  for (char C : Option->getValueAsString("Name"))
200    if (isalnum(C))
201      return true;
202  return false;
203}
204
205void emitHeading(int Depth, std::string Heading, raw_ostream &OS) {
206  assert(Depth < 8 && "groups nested too deeply");
207  OS << Heading << '\n'
208     << std::string(Heading.size(), "=~-_'+<>"[Depth]) << "\n";
209}
210
211/// Get the value of field \p Primary, if possible. If \p Primary does not
212/// exist, get the value of \p Fallback and escape it for rST emission.
213std::string getRSTStringWithTextFallback(const Record *R, StringRef Primary,
214                                         StringRef Fallback) {
215  for (auto Field : {Primary, Fallback}) {
216    if (auto *V = R->getValue(Field)) {
217      StringRef Value;
218      if (auto *SV = dyn_cast_or_null<StringInit>(V->getValue()))
219        Value = SV->getValue();
220      if (!Value.empty())
221        return Field == Primary ? Value.str() : escapeRST(Value);
222    }
223  }
224  return std::string(StringRef());
225}
226
227void emitOptionWithArgs(StringRef Prefix, const Record *Option,
228                        ArrayRef<StringRef> Args, raw_ostream &OS) {
229  OS << Prefix << escapeRST(Option->getValueAsString("Name"));
230
231  std::pair<StringRef, StringRef> Separators =
232      getSeparatorsForKind(Option->getValueAsDef("Kind"));
233
234  StringRef Separator = Separators.first;
235  for (auto Arg : Args) {
236    OS << Separator << escapeRST(Arg);
237    Separator = Separators.second;
238  }
239}
240
241void emitOptionName(StringRef Prefix, const Record *Option, raw_ostream &OS) {
242  // Find the arguments to list after the option.
243  unsigned NumArgs = getNumArgsForKind(Option->getValueAsDef("Kind"), Option);
244  bool HasMetaVarName = !Option->isValueUnset("MetaVarName");
245
246  std::vector<std::string> Args;
247  if (HasMetaVarName)
248    Args.push_back(std::string(Option->getValueAsString("MetaVarName")));
249  else if (NumArgs == 1)
250    Args.push_back("<arg>");
251
252  // Fill up arguments if this option didn't provide a meta var name or it
253  // supports an unlimited number of arguments. We can't see how many arguments
254  // already are in a meta var name, so assume it has right number. This is
255  // needed for JoinedAndSeparate options so that there arent't too many
256  // arguments.
257  if (!HasMetaVarName || NumArgs == UnlimitedArgs) {
258    while (Args.size() < NumArgs) {
259      Args.push_back(("<arg" + Twine(Args.size() + 1) + ">").str());
260      // Use '--args <arg1> <arg2>...' if any number of args are allowed.
261      if (Args.size() == 2 && NumArgs == UnlimitedArgs) {
262        Args.back() += "...";
263        break;
264      }
265    }
266  }
267
268  emitOptionWithArgs(Prefix, Option, std::vector<StringRef>(Args.begin(), Args.end()), OS);
269
270  auto AliasArgs = Option->getValueAsListOfStrings("AliasArgs");
271  if (!AliasArgs.empty()) {
272    Record *Alias = Option->getValueAsDef("Alias");
273    OS << " (equivalent to ";
274    emitOptionWithArgs(
275        Alias->getValueAsListOfStrings("Prefixes").front(), Alias,
276        AliasArgs, OS);
277    OS << ")";
278  }
279}
280
281bool emitOptionNames(const Record *Option, raw_ostream &OS, bool EmittedAny) {
282  for (auto &Prefix : Option->getValueAsListOfStrings("Prefixes")) {
283    if (EmittedAny)
284      OS << ", ";
285    emitOptionName(Prefix, Option, OS);
286    EmittedAny = true;
287  }
288  return EmittedAny;
289}
290
291template <typename Fn>
292void forEachOptionName(const DocumentedOption &Option, const Record *DocInfo,
293                       Fn F) {
294  F(Option.Option);
295
296  for (auto *Alias : Option.Aliases)
297    if (!isExcluded(Alias, DocInfo) && canSphinxCopeWithOption(Option.Option))
298      F(Alias);
299}
300
301void emitOption(const DocumentedOption &Option, const Record *DocInfo,
302                raw_ostream &OS) {
303  if (isExcluded(Option.Option, DocInfo))
304    return;
305  if (Option.Option->getValueAsDef("Kind")->getName() == "KIND_UNKNOWN" ||
306      Option.Option->getValueAsDef("Kind")->getName() == "KIND_INPUT")
307    return;
308  if (!canSphinxCopeWithOption(Option.Option))
309    return;
310
311  // HACK: Emit a different program name with each option to work around
312  // sphinx's inability to cope with options that differ only by punctuation
313  // (eg -ObjC vs -ObjC++, -G vs -G=).
314  std::vector<std::string> SphinxOptionIDs;
315  forEachOptionName(Option, DocInfo, [&](const Record *Option) {
316    for (auto &Prefix : Option->getValueAsListOfStrings("Prefixes"))
317      SphinxOptionIDs.push_back(std::string(getSphinxOptionID(
318          (Prefix + Option->getValueAsString("Name")).str())));
319  });
320  assert(!SphinxOptionIDs.empty() && "no flags for option");
321  static std::map<std::string, int> NextSuffix;
322  int SphinxWorkaroundSuffix = NextSuffix[*std::max_element(
323      SphinxOptionIDs.begin(), SphinxOptionIDs.end(),
324      [&](const std::string &A, const std::string &B) {
325        return NextSuffix[A] < NextSuffix[B];
326      })];
327  for (auto &S : SphinxOptionIDs)
328    NextSuffix[S] = SphinxWorkaroundSuffix + 1;
329  if (SphinxWorkaroundSuffix)
330    OS << ".. program:: " << DocInfo->getValueAsString("Program")
331       << SphinxWorkaroundSuffix << "\n";
332
333  // Emit the names of the option.
334  OS << ".. option:: ";
335  bool EmittedAny = false;
336  forEachOptionName(Option, DocInfo, [&](const Record *Option) {
337    EmittedAny = emitOptionNames(Option, OS, EmittedAny);
338  });
339  if (SphinxWorkaroundSuffix)
340    OS << "\n.. program:: " << DocInfo->getValueAsString("Program");
341  OS << "\n\n";
342
343  // Emit the description, if we have one.
344  std::string Description =
345      getRSTStringWithTextFallback(Option.Option, "DocBrief", "HelpText");
346  if (!Description.empty())
347    OS << Description << "\n\n";
348}
349
350void emitDocumentation(int Depth, const Documentation &Doc,
351                       const Record *DocInfo, raw_ostream &OS);
352
353void emitGroup(int Depth, const DocumentedGroup &Group, const Record *DocInfo,
354               raw_ostream &OS) {
355  if (isExcluded(Group.Group, DocInfo))
356    return;
357
358  emitHeading(Depth,
359              getRSTStringWithTextFallback(Group.Group, "DocName", "Name"), OS);
360
361  // Emit the description, if we have one.
362  std::string Description =
363      getRSTStringWithTextFallback(Group.Group, "DocBrief", "HelpText");
364  if (!Description.empty())
365    OS << Description << "\n\n";
366
367  // Emit contained options and groups.
368  emitDocumentation(Depth + 1, Group, DocInfo, OS);
369}
370
371void emitDocumentation(int Depth, const Documentation &Doc,
372                       const Record *DocInfo, raw_ostream &OS) {
373  for (auto &O : Doc.Options)
374    emitOption(O, DocInfo, OS);
375  for (auto &G : Doc.Groups)
376    emitGroup(Depth, G, DocInfo, OS);
377}
378
379}  // namespace
380
381void clang::EmitClangOptDocs(RecordKeeper &Records, raw_ostream &OS) {
382  const Record *DocInfo = Records.getDef("GlobalDocumentation");
383  if (!DocInfo) {
384    PrintFatalError("The GlobalDocumentation top-level definition is missing, "
385                    "no documentation will be generated.");
386    return;
387  }
388  OS << DocInfo->getValueAsString("Intro") << "\n";
389  OS << ".. program:: " << DocInfo->getValueAsString("Program") << "\n";
390
391  emitDocumentation(0, extractDocumentation(Records), DocInfo, OS);
392}
393