Comment parsing: refactor handling of command markers in AST

* Use the term 'command marker', because the semantics of 'backslash' and 'at'
  commands are the same.  (Talking about 'at commands' makes them look like a
  special entity.)

* Sink the flag down into bitfields, reducing the size of AST nodes.

* Change the flag into an enum for clarity.  Boolean function parameters are
  not very clear.

* Add unittests for new tok::at_command tokens.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176461 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 40 insertions, 30 deletions

diff --git a/lib/AST/CommentLexer.cpp b/lib/AST/CommentLexer.cpp
index 2018099417..1194520bf3 100644
--- a/lib/AST/CommentLexer.cpp
+++ b/lib/AST/CommentLexer.cpp
@@ -298,7 +298,11 @@ void Lexer::lexCommentText(Token &T) {
     switch(*TokenPtr) {
       case '\\':
       case '@': {
-        bool AtCommand = (*TokenPtr == '@');
+        // Commands that start with a backslash and commands that start with
+        // 'at' have equivalent semantics.  But we keep information about the
+        // exact syntax in AST for comments.
+        tok::TokenKind CommandKind =
+            (*TokenPtr == '@') ? tok::at_command : tok::backslash_command;
         TokenPtr++;
         if (TokenPtr == CommentEnd) {
           formTextToken(T, TokenPtr);
@@ -359,9 +363,7 @@ void Lexer::lexCommentText(Token &T) {
           setupAndLexVerbatimLine(T, TokenPtr, Info);
           return;
         }
-        formTokenWithChars(T, TokenPtr, 
-                           (AtCommand ? tok::at_command 
-                                      : tok::backslash_command));
+        formTokenWithChars(T, TokenPtr, CommandKind);
         T.setCommandID(Info->getID());
         return;
       }
diff --git a/lib/AST/CommentParser.cpp b/lib/AST/CommentParser.cpp
index c6bd922461..09912c6188 100644
--- a/lib/AST/CommentParser.cpp
+++ b/lib/AST/CommentParser.cpp
@@ -308,23 +308,25 @@ BlockCommandComment *Parser::parseBlockCommand() {
   bool IsParam = false;
   bool IsTParam = false;
   const CommandInfo *Info = Traits.getCommandInfo(Tok.getCommandID());
+  CommandMarkerKind CommandMarker =
+      Tok.is(tok::backslash_command) ? CMK_Backslash : CMK_At;
   if (Info->IsParamCommand) {
     IsParam = true;
     PC = S.actOnParamCommandStart(Tok.getLocation(),
                                   Tok.getEndLocation(),
                                   Tok.getCommandID(),
-                                  Tok.is(tok::at_command));
+                                  CommandMarker);
   } else if (Info->IsTParamCommand) {
     IsTParam = true;
     TPC = S.actOnTParamCommandStart(Tok.getLocation(),
                                     Tok.getEndLocation(),
                                     Tok.getCommandID(),
-                                    Tok.is(tok::at_command));
+                                    CommandMarker);
   } else {
     BC = S.actOnBlockCommandStart(Tok.getLocation(),
                                   Tok.getEndLocation(),
                                   Tok.getCommandID(),
-                                  Tok.is(tok::at_command));
+                                  CommandMarker);
   }
   consumeToken();
 
diff --git a/lib/AST/CommentSema.cpp b/lib/AST/CommentSema.cpp
index dab48e05df..d959d19b91 100644
--- a/lib/AST/CommentSema.cpp
+++ b/lib/AST/CommentSema.cpp
@@ -47,11 +47,13 @@ ParagraphComment *Sema::actOnParagraphComment(
   return new (Allocator) ParagraphComment(Content);
 }
 
-BlockCommandComment *Sema::actOnBlockCommandStart(SourceLocation LocBegin,
-                                                  SourceLocation LocEnd,
-                                                  unsigned CommandID,
-                                                  bool AtCommand) {
-  return new (Allocator) BlockCommandComment(LocBegin, LocEnd, CommandID, AtCommand);
+BlockCommandComment *Sema::actOnBlockCommandStart(
+                                      SourceLocation LocBegin,
+                                      SourceLocation LocEnd,
+                                      unsigned CommandID,
+                                      CommandMarkerKind CommandMarker) {
+  return new (Allocator) BlockCommandComment(LocBegin, LocEnd, CommandID,
+                                             CommandMarker);
 }
 
 void Sema::actOnBlockCommandArgs(BlockCommandComment *Command,
@@ -68,17 +70,19 @@ void Sema::actOnBlockCommandFinish(BlockCommandComment *Command,
   checkDeprecatedCommand(Command);
 }
 
-ParamCommandComment *Sema::actOnParamCommandStart(SourceLocation LocBegin,
-                                                  SourceLocation LocEnd,
-                                                  unsigned CommandID,
-                                                  bool AtCommand) {
+ParamCommandComment *Sema::actOnParamCommandStart(
+                                      SourceLocation LocBegin,
+                                      SourceLocation LocEnd,
+                                      unsigned CommandID,
+                                      CommandMarkerKind CommandMarker) {
   ParamCommandComment *Command =
-      new (Allocator) ParamCommandComment(LocBegin, LocEnd, CommandID, AtCommand);
+      new (Allocator) ParamCommandComment(LocBegin, LocEnd, CommandID,
+                                          CommandMarker);
 
   if (!isFunctionDecl())
     Diag(Command->getLocation(),
          diag::warn_doc_param_not_attached_to_a_function_decl)
-      << AtCommand
+      << CommandMarker
       << Command->getCommandNameRange(Traits);
 
   return Command;
@@ -163,17 +167,19 @@ void Sema::actOnParamCommandFinish(ParamCommandComment *Command,
   checkBlockCommandEmptyParagraph(Command);
 }
 
-TParamCommandComment *Sema::actOnTParamCommandStart(SourceLocation LocBegin,
-                                                    SourceLocation LocEnd,
-                                                    unsigned CommandID,
-                                                    bool AtCommand) {
+TParamCommandComment *Sema::actOnTParamCommandStart(
+                                      SourceLocation LocBegin,
+                                      SourceLocation LocEnd,
+                                      unsigned CommandID,
+                                      CommandMarkerKind CommandMarker) {
   TParamCommandComment *Command =
-      new (Allocator) TParamCommandComment(LocBegin, LocEnd, CommandID, AtCommand);
+      new (Allocator) TParamCommandComment(LocBegin, LocEnd, CommandID,
+                                           CommandMarker);
 
   if (!isTemplateOrSpecialization())
     Diag(Command->getLocation(),
          diag::warn_doc_tparam_not_attached_to_a_template_decl)
-      << AtCommand
+      << CommandMarker
       << Command->getCommandNameRange(Traits);
 
   return Command;
@@ -437,7 +443,7 @@ void Sema::checkBlockCommandEmptyParagraph(BlockCommandComment *Command) {
     if (!DiagLoc.isValid())
       DiagLoc = Command->getCommandNameRange(Traits).getEnd();
     Diag(DiagLoc, diag::warn_doc_block_command_empty_paragraph)
-      << Command->getAtCommand()
+      << Command->getCommandMarker()
       << Command->getCommandName(Traits)
       << Command->getSourceRange();
   }
@@ -465,7 +471,7 @@ void Sema::checkReturnsCommand(const BlockCommandComment *Command) {
       }
       Diag(Command->getLocation(),
            diag::warn_doc_returns_attached_to_a_void_function)
-        << Command->getAtCommand()
+        << Command->getCommandMarker()
         << Command->getCommandName(Traits)
         << DiagKind
         << Command->getSourceRange();
@@ -477,7 +483,7 @@ void Sema::checkReturnsCommand(const BlockCommandComment *Command) {
   
   Diag(Command->getLocation(),
        diag::warn_doc_returns_not_attached_to_a_function_decl)
-    << Command->getAtCommand()
+    << Command->getCommandMarker()
     << Command->getCommandName(Traits)
     << Command->getSourceRange();
 }
@@ -510,18 +516,18 @@ void Sema::checkBlockCommandDuplicate(const BlockCommandComment *Command) {
   StringRef CommandName = Command->getCommandName(Traits);
   StringRef PrevCommandName = PrevCommand->getCommandName(Traits);
   Diag(Command->getLocation(), diag::warn_doc_block_command_duplicate)
-      << Command->getAtCommand()
+      << Command->getCommandMarker()
       << CommandName
       << Command->getSourceRange();
   if (CommandName == PrevCommandName)
     Diag(PrevCommand->getLocation(), diag::note_doc_block_command_previous)
-        << PrevCommand->getAtCommand()
+        << PrevCommand->getCommandMarker()
         << PrevCommandName
         << PrevCommand->getSourceRange();
   else
     Diag(PrevCommand->getLocation(),
          diag::note_doc_block_command_previous_alias)
-        << PrevCommand->getAtCommand()
+        << PrevCommand->getCommandMarker()
         << PrevCommandName
         << CommandName;
 }