[clang-format] Fix BeforeHash indent of comments above PPDirective

Fixes #56326.

Differential Revision: https://reviews.llvm.org/D132097

Author: owenca

clang/lib/Format/TokenAnnotator.cpp

@@ -2696,15 +2696,18 @@ void TokenAnnotator::setCommentLineLevels(
         NextNonCommentLine->First->NewlinesBefore <= 1 &&
         NextNonCommentLine->First->OriginalColumn ==
             Line->First->OriginalColumn) {
+      const bool PPDirectiveOrImportStmt =
+          NextNonCommentLine->Type == LT_PreprocessorDirective ||
+          NextNonCommentLine->Type == LT_ImportStatement;
+      if (PPDirectiveOrImportStmt)
+        Line->Type = LT_CommentAbovePPDirective;
       // Align comments for preprocessor lines with the # in column 0 if
       // preprocessor lines are not indented. Otherwise, align with the next
       // line.
-      Line->Level =
-          (Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
-           (NextNonCommentLine->Type == LT_PreprocessorDirective ||
-            NextNonCommentLine->Type == LT_ImportStatement))
-              ? 0
-              : NextNonCommentLine->Level;
+      Line->Level = Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
+                            PPDirectiveOrImportStmt
+                        ? 0
+                        : NextNonCommentLine->Level;
     } else {
       NextNonCommentLine = Line->First->isNot(tok::r_brace) ? Line : nullptr;
     }

clang/lib/Format/TokenAnnotator.h

@@ -31,6 +31,7 @@ enum LineType {
   LT_PreprocessorDirective,
   LT_VirtualFunctionDecl,
   LT_ArrayOfStructInitializer,
+  LT_CommentAbovePPDirective,
 };
 
 class AnnotatedLine {

clang/lib/Format/UnwrappedLineFormatter.cpp

@@ -60,7 +60,9 @@ class LevelIndentTracker {
     // Update the indent level cache size so that we can rely on it
     // having the right size in adjustToUnmodifiedline.
     skipLine(Line, /*UnknownIndent=*/true);
-    if (Line.InPPDirective) {
+    if (Line.InPPDirective ||
+        (Style.IndentPPDirectives == FormatStyle::PPDIS_BeforeHash &&
+         Line.Type == LT_CommentAbovePPDirective)) {
       unsigned IndentWidth =
           (Style.PPIndentWidth >= 0) ? Style.PPIndentWidth : Style.IndentWidth;
       Indent = Line.Level * IndentWidth + AdditionalIndent;

clang/unittests/Format/FormatTest.cpp

@@ -4954,6 +4954,25 @@ TEST_F(FormatTest, IndentsPPDirectiveWithPPIndentWidth) {
                "    int y = 0;\n"
                "}\n",
                style);
+  verifyFormat("#if 1\n"
+               " // some comments\n"
+               " // another\n"
+               " #define foo 1\n"
+               "// not a define comment\n"
+               "void bar() {\n"
+               "    // comment\n"
+               "    int y = 0;\n"
+               "}",
+               "#if 1\n"
+               "// some comments\n"
+               "// another\n"
+               "#define foo 1\n"
+               "// not a define comment\n"
+               "void bar() {\n"
+               "  // comment\n"
+               "  int y = 0;\n"
+               "}",
+               style);
 }
 
 TEST_F(FormatTest, IndentsPPDirectiveInReducedSpace) {