Fix PR3917: the location of a #line directive is the location of the first _.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69485 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 7e695a5..330e2a1 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -485,6 +485,10 @@
// be affected by #line.
SourceLocation Loc = Tok.getLocation();
+ // Advance to the location of the first _, this might not be the first byte
+ // of the token if it starts with an escaped newline.
+ Loc = AdvanceToTokenCharacter(Loc, 0);
+
// One wrinkle here is that GCC expands __LINE__ to location of the *end* of
// a macro instantiation. This doesn't matter for object-like macros, but
// can matter for a function-like macro that expands to contain __LINE__.
diff --git a/test/Preprocessor/line-directive.c b/test/Preprocessor/line-directive.c
index 04c69a6..a9ed4bc 100644
--- a/test/Preprocessor/line-directive.c
+++ b/test/Preprocessor/line-directive.c
@@ -79,3 +79,11 @@
#line 010 // expected-warning {{#line directive interprets number as decimal, not octal}}
extern int array[__LINE__ == 10 ? 1:-1];
+/* PR3917 */
+#line 41
+extern char array2[\
+_\
+_LINE__ == 42 ? 1: -1]; /* line marker is location of first _ */
+
+
+