[clang] 4b97649 - [clang-format] Fix overlapping replacements before PPDirectives

[Owen Pan via cfe-commits]

Author: Owen Pan
Date: 2023-06-03T12:33:03-07:00
New Revision: 4b9764959dc4b8783e18747c1742ab164e4bc4ee

URL: https://github.com/llvm/llvm-project/commit/4b9764959dc4b8783e18747c1742ab164e4bc4ee
DIFF: https://github.com/llvm/llvm-project/commit/4b9764959dc4b8783e18747c1742ab164e4bc4ee.diff

LOG: [clang-format] Fix overlapping replacements before PPDirectives

If the first token of an annotated line is finalized, reuse its
NewlinesBefore value to avoid potential overlapping whitespace
replacements before preprocessor branching directives.

Fixes #62892.

Differential Revision: https://reviews.llvm.org/D151954

Added: 
    

Modified: 
    clang/lib/Format/UnwrappedLineFormatter.cpp
    clang/unittests/Format/FormatTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index 33be74dfe1b9f..fc5d4150ed777 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -1418,19 +1418,12 @@ unsigned UnwrappedLineFormatter::format(
   return Penalty;
 }
 
-void UnwrappedLineFormatter::formatFirstToken(
-    const AnnotatedLine &Line, const AnnotatedLine *PreviousLine,
-    const AnnotatedLine *PrevPrevLine,
-    const SmallVectorImpl<AnnotatedLine *> &Lines, unsigned Indent,
-    unsigned NewlineIndent) {
-  FormatToken &RootToken = *Line.First;
-  if (RootToken.is(tok::eof)) {
-    unsigned Newlines = std::min(RootToken.NewlinesBefore, 1u);
-    unsigned TokenIndent = Newlines ? NewlineIndent : 0;
-    Whitespaces->replaceWhitespace(RootToken, Newlines, TokenIndent,
-                                   TokenIndent);
-    return;
-  }
+static auto newlinesBeforeLine(const AnnotatedLine &Line,
+                               const AnnotatedLine *PreviousLine,
+                               const AnnotatedLine *PrevPrevLine,
+                               const SmallVectorImpl<AnnotatedLine *> &Lines,
+                               const FormatStyle &Style) {
+  const auto &RootToken = *Line.First;
   unsigned Newlines =
       std::min(RootToken.NewlinesBefore, Style.MaxEmptyLinesToKeep + 1);
   // Remove empty lines before "}" where applicable.
@@ -1510,6 +1503,27 @@ void UnwrappedLineFormatter::formatFirstToken(
     }
   }
 
+  return Newlines;
+}
+
+void UnwrappedLineFormatter::formatFirstToken(
+    const AnnotatedLine &Line, const AnnotatedLine *PreviousLine,
+    const AnnotatedLine *PrevPrevLine,
+    const SmallVectorImpl<AnnotatedLine *> &Lines, unsigned Indent,
+    unsigned NewlineIndent) {
+  FormatToken &RootToken = *Line.First;
+  if (RootToken.is(tok::eof)) {
+    unsigned Newlines = std::min(RootToken.NewlinesBefore, 1u);
+    unsigned TokenIndent = Newlines ? NewlineIndent : 0;
+    Whitespaces->replaceWhitespace(RootToken, Newlines, TokenIndent,
+                                   TokenIndent);
+    return;
+  }
+
+  const auto Newlines =
+      RootToken.Finalized
+          ? RootToken.NewlinesBefore
+          : newlinesBeforeLine(Line, PreviousLine, PrevPrevLine, Lines, Style);
   if (Newlines)
     Indent = NewlineIndent;
 

diff  --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 28a4008080566..f188ab6f581cf 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -12856,6 +12856,22 @@ TEST_F(FormatTest, FormatsAfterAccessModifiers) {
                "  void f() {}\n"
                "};\n",
                Style);
+  verifyFormat("struct foo {\n"
+               "#ifdef FOO\n"
+               "#else\n"
+               "private:\n"
+               "\n"
+               "#endif\n"
+               "};",
+               "struct foo {\n"
+               "#ifdef FOO\n"
+               "#else\n"
+               "private:\n"
+               "\n"
+               "\n"
+               "#endif\n"
+               "};",
+               Style);
 
   Style.EmptyLineAfterAccessModifier = FormatStyle::ELAAMS_Always;
   verifyFormat("struct foo {\n"