4 files changed, 20 insertions, 10 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index e73bcba7951..5e8a2497fea 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -174,6 +174,7 @@ struct ScalarEnumerationTraits<FormatStyle::PPDirectiveIndentStyle> {
   static void enumeration(IO &IO, FormatStyle::PPDirectiveIndentStyle &Value) {
     IO.enumCase(Value, "None", FormatStyle::PPDIS_None);
     IO.enumCase(Value, "AfterHash", FormatStyle::PPDIS_AfterHash);
+    IO.enumCase(Value, "BeforeHash", FormatStyle::PPDIS_BeforeHash);
   }
 };
 
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index bd4591189f4..eeaceb82f9f 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1924,12 +1924,15 @@ void TokenAnnotator::setCommentLineLevels(
         NextNonCommentLine->First->NewlinesBefore <= 1 &&
         NextNonCommentLine->First->OriginalColumn ==
             (*I)->First->OriginalColumn) {
-      // Align comments for preprocessor lines with the # in column 0.
-      // Otherwise, align with the next line.
-      (*I)->Level = (NextNonCommentLine->Type == LT_PreprocessorDirective ||
-                     NextNonCommentLine->Type == LT_ImportStatement)
-                        ? 0
-                        : NextNonCommentLine->Level;
+      // Align comments for preprocessor lines with the # in column 0 if
+      // preprocessor lines are not indented. Otherwise, align with the next
+      // line.
+      (*I)->Level =
+          (Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
+           (NextNonCommentLine->Type == LT_PreprocessorDirective ||
+            NextNonCommentLine->Type == LT_ImportStatement))
+              ? 0
+              : NextNonCommentLine->Level;
     } else {
       NextNonCommentLine = (*I)->First->isNot(tok::r_brace) ? (*I) : nullptr;
     }
diff --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index f14e3851c8d..5d8142a1cfb 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -1178,8 +1178,10 @@ void UnwrappedLineFormatter::formatFirstToken(
   if (Newlines)
     Indent = NewlineIndent;
 
-  // Preprocessor directives get indented after the hash, if indented.
-  if (Line.Type == LT_PreprocessorDirective || Line.Type == LT_ImportStatement)
+  // Preprocessor directives get indented before the hash only if specified
+  if (Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
+      (Line.Type == LT_PreprocessorDirective ||
+       Line.Type == LT_ImportStatement))
     Indent = 0;
 
   Whitespaces->replaceWhitespace(RootToken, Newlines, Indent, Indent,
diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 3abb6f40d74..4bd71aa26d5 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -655,6 +655,7 @@ void UnwrappedLineParser::parseChildBlock() {
 void UnwrappedLineParser::parsePPDirective() {
   assert(FormatTok->Tok.is(tok::hash) && "'#' expected");
   ScopedMacroState MacroState(*Line, Tokens, FormatTok);
+
   nextToken();
 
   if (!FormatTok->Tok.getIdentifierInfo()) {
@@ -823,7 +824,7 @@ void UnwrappedLineParser::parsePPDefine() {
           FormatTok->WhitespaceRange.getEnd()) {
     parseParens();
   }
-  if (Style.IndentPPDirectives == FormatStyle::PPDIS_AfterHash)
+  if (Style.IndentPPDirectives != FormatStyle::PPDIS_None)
     Line->Level += PPBranchLevel + 1;
   addUnwrappedLine();
   ++Line->Level;
@@ -840,7 +841,7 @@ void UnwrappedLineParser::parsePPUnknown() {
   do {
     nextToken();
   } while (!eof());
-  if (Style.IndentPPDirectives == FormatStyle::PPDIS_AfterHash)
+  if (Style.IndentPPDirectives != FormatStyle::PPDIS_None)
     Line->Level += PPBranchLevel + 1;
   addUnwrappedLine();
 }
@@ -2671,6 +2672,9 @@ void UnwrappedLineParser::readToken(int LevelDifference) {
       // Comments stored before the preprocessor directive need to be output
       // before the preprocessor directive, at the same level as the
       // preprocessor directive, as we consider them to apply to the directive.
+      if (Style.IndentPPDirectives == FormatStyle::PPDIS_BeforeHash &&
+          PPBranchLevel > 0)
+        Line->Level += PPBranchLevel;
       flushComments(isOnNewLine(*FormatTok));
       parsePPDirective();
     }