clang-format: fix block OpeningLineIndex around preprocessor

Summary:
The current code would return an incorrect value when a preprocessor
directive is present immediately after the opening brace: this causes
the nanespace end comment fixer to break in some places, for exemple it
would not add the comment in this case:

  namespace a {
  #define FOO
  }

Fixing the computation is simple enough, but it was breaking a feature,
as it would cause comments to be added also when the namespace
declaration was dependant on conditional compilation.

To fix this, a hash of the current preprocessor stack/branches is
computed at the beginning of parseBlock(), so that we explicitely do not
store the OpeningLineIndex when the beginning and end of the block are
not in the same preprocessor conditions.

Tthe hash is computed based on the line, but this could propbably be
improved by using the actual condition, so that clang-format would be
able to match multiple identical #ifdef blocks.

Reviewers: krasimir, djasper

Reviewed By: krasimir

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D35483

llvm-svn: 309369

1 files changed, 13 insertions, 2 deletions

diff --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
index 5e1eef76619..47e41b3bb29 100644
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -160,6 +160,11 @@ private:
 
   bool isOnNewLine(const FormatToken &FormatTok);
 
+  // Compute hash of the current preprocessor branch.
+  // This is used to identify the different branches, and thus track if block
+  // open and close in the same branch.
+  size_t computePPHash() const;
+
   // FIXME: We are constantly running into bugs where Line.Level is incorrectly
   // subtracted from beyond 0. Introduce a method to subtract from Line.Level
   // and use that everywhere in the Parser.
@@ -178,7 +183,7 @@ private:
 
   // Preprocessor directives are parsed out-of-order from other unwrapped lines.
   // Thus, we need to keep a list of preprocessor directives to be reported
-  // after an unwarpped line that has been started was finished.
+  // after an unwrapped line that has been started was finished.
   SmallVector<UnwrappedLine, 4> PreprocessorDirectives;
 
   // New unwrapped lines are added via CurrentLines.
@@ -211,8 +216,14 @@ private:
     PP_Unreachable  // #if 0 or a conditional preprocessor block inside #if 0
   };
 
+  struct PPBranch {
+    PPBranch(PPBranchKind Kind, size_t Line) : Kind(Kind), Line(Line) {}
+    PPBranchKind Kind;
+    size_t Line;
+  };
+
   // Keeps a stack of currently active preprocessor branching directives.
-  SmallVector<PPBranchKind, 16> PPStack;
+  SmallVector<PPBranch, 16> PPStack;
 
   // The \c UnwrappedLineParser re-parses the code for each combination
   // of preprocessor branches that can be taken.