+/// that as well. This assumes that leading dashes have already been stripped.
+static Option *LookupOption(StringRef &Arg, StringRef &Value,
+ const StringMap<Option*> &OptionsMap) {
+ // Reject all dashes.
+ if (Arg.empty()) return 0;
+
+ size_t EqualPos = Arg.find('=');
+
+ // If we have an equals sign, remember the value.
+ if (EqualPos == StringRef::npos) {
+ // Look up the option.
+ StringMap<Option*>::const_iterator I = OptionsMap.find(Arg);
+ return I != OptionsMap.end() ? I->second : 0;
+ }
+
+ // If the argument before the = is a valid option name, we match. If not,
+ // return Arg unmolested.
+ StringMap<Option*>::const_iterator I =
+ OptionsMap.find(Arg.substr(0, EqualPos));
+ if (I == OptionsMap.end()) return 0;
+
+ Value = Arg.substr(EqualPos+1);
+ Arg = Arg.substr(0, EqualPos);
+ return I->second;
+}
+
+/// LookupNearestOption - Lookup the closest match to the option specified by
+/// the specified option on the command line. If there is a value specified
+/// (after an equal sign) return that as well. This assumes that leading dashes
+/// have already been stripped.
+static Option *LookupNearestOption(StringRef Arg,
+ const StringMap<Option*> &OptionsMap,
+ std::string &NearestString) {
+ // Reject all dashes.
+ if (Arg.empty()) return 0;
+
+ // Split on any equal sign.
+ std::pair<StringRef, StringRef> SplitArg = Arg.split('=');
+ StringRef &LHS = SplitArg.first; // LHS == Arg when no '=' is present.
+ StringRef &RHS = SplitArg.second;
+
+ // Find the closest match.
+ Option *Best = 0;
+ unsigned BestDistance = 0;
+ for (StringMap<Option*>::const_iterator it = OptionsMap.begin(),
+ ie = OptionsMap.end(); it != ie; ++it) {
+ Option *O = it->second;
+ SmallVector<const char*, 16> OptionNames;
+ O->getExtraOptionNames(OptionNames);
+ if (O->ArgStr[0])
+ OptionNames.push_back(O->ArgStr);
+
+ bool PermitValue = O->getValueExpectedFlag() != cl::ValueDisallowed;
+ StringRef Flag = PermitValue ? LHS : Arg;
+ for (size_t i = 0, e = OptionNames.size(); i != e; ++i) {
+ StringRef Name = OptionNames[i];
+ unsigned Distance = StringRef(Name).edit_distance(
+ Flag, /*AllowReplacements=*/true, /*MaxEditDistance=*/BestDistance);
+ if (!Best || Distance < BestDistance) {
+ Best = O;
+ BestDistance = Distance;
+ if (RHS.empty() || !PermitValue)
+ NearestString = OptionNames[i];
+ else
+ NearestString = std::string(OptionNames[i]) + "=" + RHS.str();
+ }
+ }
+ }