fix rdar://6757323, where an escaped newline in a // comment
was causing the char after the newline to get eaten.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@68430 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 3a3e86a..059afe2 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -848,6 +848,14 @@
LexingRawMode = true;
C = getAndAdvanceChar(CurPtr, Result);
LexingRawMode = OldRawMode;
+
+ // If the char that we finally got was a \n, then we must have had something
+ // like \<newline><newline>. We don't want to have consumed the second
+ // newline, we want CurPtr, to end up pointing to it down below.
+ if (C == '\n' || C == '\r') {
+ --CurPtr;
+ C = 'x'; // doesn't matter what this is.
+ }
// If we read multiple characters, and one of those characters was a \r or
// \n, then we had an escaped newline within the comment. Emit diagnostic
diff --git a/test/Lexer/comment-escape.c b/test/Lexer/comment-escape.c
new file mode 100644
index 0000000..c568cd6
--- /dev/null
+++ b/test/Lexer/comment-escape.c
@@ -0,0 +1,6 @@
+// RUN: clang -fsyntax-only %s
+// rdar://6757323
+// foo \
+
+#define blork 32
+