[Gardening] Do not store start/end line in SingleRawComment

The start and end lines were only used while constructing the comments,
so move the line tracking into that method instead of storing it in each
comment.

Author: bnbarham

include/swift/AST/RawComment.h

@@ -34,12 +34,10 @@ struct SingleRawComment {
   StringRef RawText;
 
   unsigned Kind : 8;
-  unsigned StartColumn : 16;
-  unsigned StartLine;
-  unsigned EndLine;
+  unsigned ColumnIndent : 16;
 
   SingleRawComment(CharSourceRange Range, const SourceManager &SourceMgr);
-  SingleRawComment(StringRef RawText, unsigned StartColumn);
+  SingleRawComment(StringRef RawText, unsigned ColumnIndent);
 
   SingleRawComment(const SingleRawComment &) = default;
   SingleRawComment &operator=(const SingleRawComment &) = default;

lib/AST/ASTPrinter.cpp

@@ -641,7 +641,7 @@ class PrintAST : public ASTVisitor<PrintAST> {
       Lines.clear();
 
       StringRef RawText = SRC.RawText.rtrim("\n\r");
-      unsigned WhitespaceToTrim = SRC.StartColumn - 1;
+      unsigned WhitespaceToTrim = SRC.ColumnIndent - 1;
       trimLeadingWhitespaceFromLines(RawText, WhitespaceToTrim, Lines);
 
       for (auto Line : Lines) {

lib/AST/Module.cpp

@@ -879,10 +879,10 @@ SourceFile::getBasicLocsForDecl(const Decl *D) const {
   Result.SourceFilePath = SM.getDisplayNameForLoc(D->getLoc());
 
   for (const auto &SRC : D->getRawComment(/*SerializedOK*/false).Comments) {
-    Result.DocRanges.push_back(std::make_pair(
-      SourcePosition { SRC.StartLine, SRC.StartColumn },
-      SRC.Range.getByteLength())
-    );
+    auto LineAndCol = SM.getLineAndColumnInBuffer(SRC.Range.getStart());
+    Result.DocRanges.push_back(
+        std::make_pair(SourcePosition{LineAndCol.first, LineAndCol.second},
+                       SRC.Range.getByteLength()));
   }
 
   auto setLineColumn = [&SM](SourcePosition &Home, SourceLoc Loc) {

lib/AST/RawComment.cpp

@@ -61,71 +61,57 @@ SingleRawComment::SingleRawComment(CharSourceRange Range,
                                    const SourceManager &SourceMgr)
     : Range(Range), RawText(SourceMgr.extractText(Range)),
       Kind(static_cast<unsigned>(getCommentKind(RawText))) {
-  auto StartLineAndColumn =
-      SourceMgr.getLineAndColumnInBuffer(Range.getStart());
-  StartLine = StartLineAndColumn.first;
-  StartColumn = StartLineAndColumn.second;
-  EndLine = SourceMgr.getLineAndColumnInBuffer(Range.getEnd()).first;
+  ColumnIndent = SourceMgr.getLineAndColumnInBuffer(Range.getStart()).second;
 }
 
-SingleRawComment::SingleRawComment(StringRef RawText, unsigned StartColumn)
+SingleRawComment::SingleRawComment(StringRef RawText, unsigned ColumnIndent)
     : RawText(RawText), Kind(static_cast<unsigned>(getCommentKind(RawText))),
-      StartColumn(StartColumn), StartLine(0), EndLine(0) {}
-
-static void addCommentToList(SmallVectorImpl<SingleRawComment> &Comments,
-                             const SingleRawComment &SRC) {
-  // TODO: consider producing warnings when we decide not to merge comments.
-
-  if (SRC.isOrdinary()) {
-    // Skip gyb comments that are line number markers.
-    if (SRC.RawText.startswith("// ###"))
-      return;
-
-    Comments.clear();
-    return;
-  }
-
-  // If this is the first documentation comment, save it (because there isn't
-  // anything to merge it with).
-  if (Comments.empty()) {
-    Comments.push_back(SRC);
-    return;
-  }
-
-  auto &Last = Comments.back();
-
-  // Merge comments if they are on same or consecutive lines.
-  if (Last.EndLine + 1 < SRC.StartLine) {
-    Comments.clear();
-    return;
-  }
-
-  Comments.push_back(SRC);
-}
+      ColumnIndent(ColumnIndent) {}
 
 static RawComment toRawComment(ASTContext &Context, CharSourceRange Range) {
   if (Range.isInvalid())
     return RawComment();
 
-  auto &SourceMgr = Context.SourceMgr;
-  unsigned BufferID = SourceMgr.findBufferContainingLoc(Range.getStart());
-  unsigned Offset = SourceMgr.getLocOffsetInBuffer(Range.getStart(), BufferID);
-  unsigned EndOffset = SourceMgr.getLocOffsetInBuffer(Range.getEnd(), BufferID);
+  auto &SM = Context.SourceMgr;
+  unsigned BufferID = SM.findBufferContainingLoc(Range.getStart());
+  unsigned Offset = SM.getLocOffsetInBuffer(Range.getStart(), BufferID);
+  unsigned EndOffset = SM.getLocOffsetInBuffer(Range.getEnd(), BufferID);
   LangOptions FakeLangOpts;
-  Lexer L(FakeLangOpts, SourceMgr, BufferID, nullptr, LexerMode::Swift,
-          HashbangMode::Disallowed,
-          CommentRetentionMode::ReturnAsTokens,
-          TriviaRetentionMode::WithoutTrivia,
-          Offset, EndOffset);
+  Lexer L(FakeLangOpts, SM, BufferID, nullptr, LexerMode::Swift,
+          HashbangMode::Disallowed, CommentRetentionMode::ReturnAsTokens,
+          TriviaRetentionMode::WithoutTrivia, Offset, EndOffset);
+
   SmallVector<SingleRawComment, 16> Comments;
   Token Tok;
+  unsigned LastEnd = 0;
   while (true) {
     L.lex(Tok);
     if (Tok.is(tok::eof))
       break;
     assert(Tok.is(tok::comment));
-    addCommentToList(Comments, SingleRawComment(Tok.getRange(), SourceMgr));
+
+    auto SRC = SingleRawComment(Tok.getRange(), SM);
+    if (SRC.isOrdinary()) {
+      // Skip gyb comments that are line number markers.
+      if (!SRC.RawText.startswith("// ###")) {
+        Comments.clear();
+        LastEnd = 0;
+      }
+      continue;
+    }
+
+    // Merge comments if they are on same or consecutive lines.
+    unsigned Start =
+        SM.getLineAndColumnInBuffer(Tok.getRange().getStart()).first;
+    if (LastEnd > 0 && LastEnd + 1 < Start) {
+      Comments.clear();
+      LastEnd = 0;
+    } else {
+      Comments.push_back(SRC);
+      LastEnd = SM.getLineAndColumnInBuffer(Tok.getRange().getEnd()).first;
+    }
   }
+
   RawComment Result;
   Result.Comments = Context.AllocateCopy(Comments);
   return Result;
@@ -159,25 +145,24 @@ RawComment Decl::getRawComment(bool SerializedOK) const {
   switch (Unit->getKind()) {
   case FileUnitKind::SerializedAST: {
     if (SerializedOK) {
-      if (const auto *CachedLocs = getSerializedLocs()) {
-        if (!CachedLocs->DocRanges.empty()) {
-          SmallVector<SingleRawComment, 4> SRCs;
-          for (const auto &Range : CachedLocs->DocRanges) {
-            if (Range.isValid()) {
-              SRCs.push_back({ Range, Context.SourceMgr });
-            } else {
-              // if we've run into an invalid range, don't bother trying to load
-              // any of the other comments
-              SRCs.clear();
-              break;
-            }
+      auto *CachedLocs = getSerializedLocs();
+      if (!CachedLocs->DocRanges.empty()) {
+        SmallVector<SingleRawComment, 4> SRCs;
+        for (const auto &Range : CachedLocs->DocRanges) {
+          if (Range.isValid()) {
+            SRCs.push_back({Range, Context.SourceMgr});
+          } else {
+            // if we've run into an invalid range, don't bother trying to load
+            // any of the other comments
+            SRCs.clear();
+            break;
           }
-          auto RC = RawComment(Context.AllocateCopy(llvm::makeArrayRef(SRCs)));
+        }
 
-          if (!RC.isEmpty()) {
-            Context.setRawComment(this, RC, true);
-            return RC;
-          }
+        if (!SRCs.empty()) {
+          auto RC = RawComment(Context.AllocateCopy(llvm::makeArrayRef(SRCs)));
+          Context.setRawComment(this, RC, true);
+          return RC;
         }
       }
     }

lib/Markup/LineList.cpp

@@ -118,7 +118,7 @@ LineList MarkupContext::getLineList(swift::RawComment RC) {
         unsigned NewlineBytes = swift::measureNewline(Cleaned);
         Cleaned = Cleaned.drop_front(NewlineBytes);
         CleanedStartLoc = CleanedStartLoc.getAdvancedLocOrInvalid(NewlineBytes);
-        HasASCIIArt = measureASCIIArt(Cleaned, C.StartColumn - 1) != 0;
+        HasASCIIArt = measureASCIIArt(Cleaned, C.ColumnIndent - 1) != 0;
       }
 
       while (!Cleaned.empty()) {
@@ -129,7 +129,7 @@ LineList MarkupContext::getLineList(swift::RawComment RC) {
         // Skip over ASCII art, if present.
         if (HasASCIIArt)
           if (unsigned ASCIIArtBytes =
-              measureASCIIArt(Cleaned, C.StartColumn - 1)) {
+                  measureASCIIArt(Cleaned, C.ColumnIndent - 1)) {
             Cleaned = Cleaned.drop_front(ASCIIArtBytes);
             CleanedStartLoc =
             CleanedStartLoc.getAdvancedLocOrInvalid(ASCIIArtBytes);

lib/Serialization/SerializeDoc.cpp

@@ -247,7 +247,7 @@ class DeclCommentTableInfo {
     out << data.Brief;
     writer.write<uint32_t>(data.Raw.Comments.size());
     for (auto C : data.Raw.Comments) {
-      writer.write<uint32_t>(C.StartColumn);
+      writer.write<uint32_t>(C.ColumnIndent);
       writer.write<uint32_t>(C.RawText.size());
       out << C.RawText;
     }