clang-format: Don't remove 'unknown' tokens.

In certain macros or incorrect string literals, the token stream can
contain 'unknown' tokens, e.g. a single backslash or a set of empty
ticks. clang-format simply treated them as whitespace and removed them
prior to this patch.

This fixes llvm.org/PR17215

llvm-svn: 192490

clang/lib/Format/Format.cpp

@@ -691,18 +691,32 @@ private:
           FormatTok->LastNewlineOffset = WhitespaceLength + i + 1;
           Column = 0;
           break;
+        case '\r':
+        case '\f':
+        case '\v':
+          Column = 0;
+          break;
         case ' ':
           ++Column;
           break;
         case '\t':
           Column += Style.TabWidth - Column % Style.TabWidth;
           break;
+        case '\\':
+          ++Column;
+          if (i + 1 == e || (FormatTok->TokenText[i + 1] != '\r' &&
+                             FormatTok->TokenText[i + 1] != '\n'))
+            FormatTok->Type = TT_ImplicitStringLiteral;
+          break;
         default:
+          FormatTok->Type = TT_ImplicitStringLiteral;
           ++Column;
           break;
         }
       }
 
+      if (FormatTok->Type == TT_ImplicitStringLiteral)
+        break;
       WhitespaceLength += FormatTok->Tok.getLength();
 
       readRawToken(*FormatTok);

clang/lib/Format/TokenAnnotator.cpp

@@ -525,7 +525,8 @@ private:
 
     // Reset token type in case we have already looked at it and then recovered
     // from an error (e.g. failure to find the matching >).
-    if (CurrentToken != NULL && CurrentToken->Type != TT_LambdaLSquare)
+    if (CurrentToken != NULL && CurrentToken->Type != TT_LambdaLSquare &&
+        CurrentToken->Type != TT_ImplicitStringLiteral)
       CurrentToken->Type = TT_Unknown;
   }
 
@@ -1292,6 +1293,8 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
                                          const FormatToken &Tok) {
   if (Tok.Tok.getIdentifierInfo() && Tok.Previous->Tok.getIdentifierInfo())
     return true; // Never ever merge two identifiers.
+  if (Tok.Previous->Type == TT_ImplicitStringLiteral)
+    return Tok.WhitespaceRange.getBegin() != Tok.WhitespaceRange.getEnd();
   if (Line.Type == LT_ObjCMethodDecl) {
     if (Tok.Previous->Type == TT_ObjCMethodSpecifier)
       return true;

clang/unittests/Format/FormatTest.cpp

@@ -1890,6 +1890,16 @@ TEST_F(FormatTest, EndOfFileEndsPPDirective) {
   EXPECT_EQ("#define A B", format("#  \\\n define  \\\n    A  \\\n       B"));
 }
 
+TEST_F(FormatTest, DoesntRemoveUnknownTokens) {
+  verifyFormat("#define A \\x20");
+  verifyFormat("#define A \\ x20");
+  EXPECT_EQ("#define A \\ x20", format("#define A \\   x20"));
+  verifyFormat("#define A ''");
+  verifyFormat("#define A ''qqq");
+  verifyFormat("#define A `qqq");
+  verifyFormat("f(\"aaaa, bbbb, \"\\\"ccccc\\\"\");");
+}
+
 TEST_F(FormatTest, IndentsPPDirectiveInReducedSpace) {
   verifyFormat("#define A(BB)", getLLVMStyleWithColumns(13));
   verifyFormat("#define A( \\\n    BB)", getLLVMStyleWithColumns(12));