clang-format: Don't corrupt macros with open braces.

Formatting:
  #define A { {
  #define B } }

Before:
  #define A               \
    {                     \
      { #define B }       \
    }

After:
  #define A               \
    {                     \
      {
  #define B               \
    }                     \
    }

This fixes llvm.org/PR22884.

llvm-svn: 232166

2 files changed, 15 insertions, 5 deletions

diff --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index 71e8b3fd6b0..6c92d79d139 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -35,10 +35,18 @@ public:
   tryFitMultipleLinesInOne(unsigned Indent,
                            SmallVectorImpl<AnnotatedLine *>::const_iterator I,
                            SmallVectorImpl<AnnotatedLine *>::const_iterator E) {
+    // Can't join the last line with anything.
+    if (I + 1 == E)
+      return 0;
     // We can never merge stuff if there are trailing line comments.
     const AnnotatedLine *TheLine = *I;
     if (TheLine->Last->is(TT_LineComment))
       return 0;
+    if (I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore)
+      return 0;
+    if (TheLine->InPPDirective &&
+        (!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline))
+      return 0;
 
     if (Style.ColumnLimit > 0 && Indent > Style.ColumnLimit)
       return 0;
@@ -51,9 +59,6 @@ public:
                 ? 0
                 : Limit - TheLine->Last->TotalLength;
 
-    if (I + 1 == E || I[1]->Type == LT_Invalid || I[1]->First->MustBreakBefore)
-      return 0;
-
     // FIXME: TheLine->Level != 0 might or might not be the right check to do.
     // If necessary, change to something smarter.
     bool MergeShortFunctions =
@@ -121,8 +126,6 @@ private:
                             unsigned Limit) {
     if (Limit == 0)
       return 0;
-    if (!I[1]->InPPDirective || I[1]->First->HasUnescapedNewline)
-      return 0;
     if (I + 2 != E && I[2]->InPPDirective && !I[2]->First->HasUnescapedNewline)
       return 0;
     if (1 + I[1]->Last->TotalLength > Limit)
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index d6ca57f3047..c0e847fe67d 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -2686,6 +2686,13 @@ TEST_F(FormatTest, MacroDefinitionsWithIncompleteCode) {
                "#define b }\\\n"
                "  a\n"
                "a");
+  verifyFormat("#define A     \\\n"
+               "  {           \\\n"
+               "    {\n"
+               "#define B     \\\n"
+               "  }           \\\n"
+               "  }",
+               getLLVMStyleWithColumns(15));
 
   verifyNoCrash("#if a\na(\n#else\n#endif\n{a");
   verifyNoCrash("a={0,1\n#if a\n#else\n;\n#endif\n}");