Improve formatting of #defines.

Two improvements:
1) Always leave at least one space before "\". Otherwise is can look bad
   and there is a risk of unwillingly joining to characters to a different
   token.
2) Use the full column limit for single-line #defines.
   Fixes llvm.org/PR15148

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@176245 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 18 insertions, 18 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 18a853f1e4..4aaae844fc 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -273,7 +273,7 @@ public:
   ///
   /// \returns The column after the last token in the last line of the
   /// \c UnwrappedLine.
-  unsigned format() {
+  unsigned format(const AnnotatedLine *NextLine) {
     // Initialize state dependent on indent.
     LineState State;
     State.Column = FirstIndent;
@@ -295,7 +295,11 @@ public:
     moveStateToNextToken(State, /*DryRun=*/ false);
 
     // If everything fits on a single line, just put it there.
-    if (Line.Last->TotalLength <= getColumnLimit() - FirstIndent) {
+    unsigned ColumnLimit = Style.ColumnLimit;
+    if (NextLine && NextLine->InPPDirective &&
+        !NextLine->First.FormatTok.HasUnescapedNewline)
+      ColumnLimit = getColumnLimit();
+    if (Line.Last->TotalLength <= ColumnLimit - FirstIndent) {
       while (State.NextToken != NULL) {
         addTokenToState(false, false, State);
       }
@@ -749,7 +753,7 @@ private:
   }
 
   unsigned getColumnLimit() {
-    return Style.ColumnLimit - (Line.InPPDirective ? 1 : 0);
+    return Style.ColumnLimit - (Line.InPPDirective ? 2 : 0);
   }
 
   /// \brief An edge in the solution space from \c Previous->State to \c State,
@@ -1112,7 +1116,8 @@ public:
         UnwrappedLineFormatter Formatter(Style, SourceMgr, TheLine, Indent,
                                          TheLine.First, Whitespaces,
                                          StructuralError);
-        PreviousEndOfLineColumn = Formatter.format();
+        PreviousEndOfLineColumn =
+            Formatter.format(I + 1 != E ? &*(I + 1) : NULL);
         IndentForLevel[TheLine.Level] = LevelIndent;
         PreviousLineWasTouched = true;
       } else {
@@ -1192,7 +1197,7 @@ private:
     if (I->Last->Type == TT_LineComment)
       return;
 
-    unsigned Limit = Style.ColumnLimit - (I->InPPDirective ? 1 : 0) - Indent;
+    unsigned Limit = Style.ColumnLimit - Indent;
     // If we already exceed the column limit, we set 'Limit' to 0. The different
     // tryMerge..() functions can then decide whether to still do merging.
     Limit = I->Last->TotalLength > Limit ? 0 : Limit - I->Last->TotalLength;
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index cc68bcb947..98e035a598 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -857,29 +857,24 @@ TEST_F(FormatTest, EndOfFileEndsPPDirective) {
 }
 
 TEST_F(FormatTest, IndentsPPDirectiveInReducedSpace) {
-  // If the macro fits in one line, we still do not get the full
-  // line, as only the next line decides whether we need an escaped newline and
-  // thus use the last column.
-  verifyFormat("#define A(B)", getLLVMStyleWithColumns(13));
-
-  verifyFormat("#define A( \\\n    B)", getLLVMStyleWithColumns(12));
-  verifyFormat("#define AA(\\\n    B)", getLLVMStyleWithColumns(12));
+  verifyFormat("#define A(BB)", getLLVMStyleWithColumns(13));
+  verifyFormat("#define A( \\\n    BB)", getLLVMStyleWithColumns(12));
   verifyFormat("#define A( \\\n    A, B)", getLLVMStyleWithColumns(12));
+  // FIXME: We never break before the macro name.
+  verifyFormat("#define AA(\\\n    B)", getLLVMStyleWithColumns(12));
 
   verifyFormat("#define A A\n#define A A");
   verifyFormat("#define A(X) A\n#define A A");
 
-  verifyFormat("#define Something Other", getLLVMStyleWithColumns(24));
-  verifyFormat("#define Something     \\\n"
-               "  Other",
-               getLLVMStyleWithColumns(23));
+  verifyFormat("#define Something Other", getLLVMStyleWithColumns(23));
+  verifyFormat("#define Something    \\\n  Other", getLLVMStyleWithColumns(22));
 }
 
 TEST_F(FormatTest, HandlePreprocessorDirectiveContext) {
   EXPECT_EQ("// some comment\n"
             "#include \"a.h\"\n"
-            "#define A(A,\\\n"
-            "          B)\n"
+            "#define A(  \\\n"
+            "    A, B)\n"
             "#include \"b.h\"\n"
             "// some comment\n",
             format("  // some comment\n"