[Support] Indent multi-line descr of enum cli options.

As noted in https://reviews.llvm.org/D93459, the formatting of
multi-line descriptions of clEnumValN and the likes is unfavorable.
Thus this patch adds support for correctly indenting these.

Reviewed By: serge-sans-paille

Differential Revision: https://reviews.llvm.org/D93494

1 files changed, 19 insertions, 6 deletions

diff --git a/llvm/lib/Support/CommandLine.cpp b/llvm/lib/Support/CommandLine.cpp
index c9d921a..93d4651 100644
--- a/llvm/lib/Support/CommandLine.cpp
+++ b/llvm/lib/Support/CommandLine.cpp
@@ -1726,6 +1726,19 @@ void Option::printHelpStr(StringRef HelpStr, size_t Indent,
   }
 }
 
+void Option::printEnumValHelpStr(StringRef HelpStr, size_t BaseIndent,
+                                 size_t FirstLineIndentedBy) {
+  const StringRef ValHelpPrefix = "  ";
+  assert(BaseIndent >= FirstLineIndentedBy + ValHelpPrefix.size());
+  std::pair<StringRef, StringRef> Split = HelpStr.split('\n');
+  outs().indent(BaseIndent - FirstLineIndentedBy)
+      << ArgHelpPrefix << ValHelpPrefix << Split.first << "\n";
+  while (!Split.second.empty()) {
+    Split = Split.second.split('\n');
+    outs().indent(BaseIndent + ValHelpPrefix.size()) << Split.first << "\n";
+  }
+}
+
 // Print out the option for the alias.
 void alias::printOptionInfo(size_t GlobalWidth) const {
   outs() << PrintArg(ArgStr);
@@ -1971,17 +1984,17 @@ void generic_parser_base::printOptionInfo(const Option &O,
       StringRef Description = getDescription(i);
       if (!shouldPrintOption(OptionName, Description, O))
         continue;
-      assert(GlobalWidth >= OptionName.size() + OptionPrefixesSize);
-      size_t NumSpaces = GlobalWidth - OptionName.size() - OptionPrefixesSize;
+      size_t FirstLineIndent = OptionName.size() + OptionPrefixesSize;
       outs() << OptionPrefix << OptionName;
       if (OptionName.empty()) {
         outs() << EmptyOption;
-        assert(NumSpaces >= EmptyOption.size());
-        NumSpaces -= EmptyOption.size();
+        assert(FirstLineIndent >= EmptyOption.size());
+        FirstLineIndent += EmptyOption.size();
       }
       if (!Description.empty())
-        outs().indent(NumSpaces) << ArgHelpPrefix << "  " << Description;
-      outs() << '\n';
+        Option::printEnumValHelpStr(Description, GlobalWidth, FirstLineIndent);
+      else
+        outs() << '\n';
     }
   } else {
     if (!O.HelpStr.empty())