[clang-format] Remove code related to trigraphs

clang/lib/Format/FormatTokenLexer.cpp

@@ -1198,7 +1198,7 @@ void FormatTokenLexer::truncateToken(size_t NewLen) {
 /// Count the length of leading whitespace in a token.
 static size_t countLeadingWhitespace(StringRef Text) {
   // Basically counting the length matched by this regex.
-  // "^([\n\r\f\v \t]|(\\\\|\\?\\?/)[\n\r])+"
+  // "^([\n\r\f\v \t]|\\\\[\n\r])+"
   // Directly using the regex turned out to be slow. With the regex
   // version formatting all files in this directory took about 1.25
   // seconds. This version took about 0.5 seconds.
@@ -1222,13 +1222,6 @@ static size_t countLeadingWhitespace(StringRef Text) {
         break;
       // Splice found, consume it.
       Cur = Lookahead + 1;
-    } else if (Cur[0] == '?' && Cur[1] == '?' && Cur[2] == '/' &&
-               (Cur[3] == '\n' || Cur[3] == '\r')) {
-      // Newlines can also be escaped by a '?' '?' '/' trigraph. By the way, the
-      // characters are quoted individually in this comment because if we write
-      // them together some compilers warn that we have a trigraph in the code.
-      assert(End - Cur >= 4);
-      Cur += 4;
     } else {
       break;
     }
@@ -1300,22 +1293,16 @@ FormatToken *FormatTokenLexer::getNextToken() {
             Style.TabWidth - (Style.TabWidth ? Column % Style.TabWidth : 0);
         break;
       case '\\':
-      case '?':
-      case '/':
-        // The text was entirely whitespace when this loop was entered. Thus
-        // this has to be an escape sequence.
-        assert(Text.substr(i, 4) == "\?\?/\r" ||
-               Text.substr(i, 4) == "\?\?/\n" ||
-               (i >= 1 && (Text.substr(i - 1, 4) == "\?\?/\r" ||
-                           Text.substr(i - 1, 4) == "\?\?/\n")) ||
-               (i >= 2 && (Text.substr(i - 2, 4) == "\?\?/\r" ||
-                           Text.substr(i - 2, 4) == "\?\?/\n")) ||
-               (Text[i] == '\\' && [&]() -> bool {
-                 size_t j = i + 1;
-                 while (j < Text.size() && isHorizontalWhitespace(Text[j]))
-                   ++j;
-                 return j < Text.size() && (Text[j] == '\n' || Text[j] == '\r');
-               }()));
+        // The code preceding the loop and in the countLeadingWhitespace
+        // function guarantees that Text is entirely whitespace, not including
+        // comments but including escaped newlines. So the character shows up,
+        // then it has to be in an escape sequence.
+        assert([&]() -> bool {
+          size_t j = i + 1;
+          while (j < Text.size() && isHorizontalWhitespace(Text[j]))
+            ++j;
+          return j < Text.size() && (Text[j] == '\n' || Text[j] == '\r');
+        }());
         InEscape = true;
         break;
       default:

clang/unittests/Format/FormatTest.cpp

@@ -6681,6 +6681,17 @@ TEST_F(FormatTest, EscapedNewlines) {
                "  int x(int a);",
                AlignLeft);
 
+  // Escaped with a trigraph.  The program just has to avoid crashing.
+  verifyNoCrash("#define A \?\?/\n"
+                "int i;\?\?/\n"
+                "  int j;");
+  verifyNoCrash("#define A \?\?/\r\n"
+                "int i;\?\?/\r\n"
+                "  int j;");
+  verifyNoCrash("#define A \?\?/\n"
+                "int i;",
+                getGoogleStyle(FormatStyle::LK_CSharp));
+
   // CRLF line endings
   verifyFormat("#define A \\\r\n  int i;  \\\r\n  int j;",
                "#define A \\\r\nint i;\\\r\n  int j;", Narrow);