Handle '#line' in '-E' that has an empty file name. Fixes <rdar://problem/8439412>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114142 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 2 deletions

diff --git a/lib/Frontend/PrintPreprocessedOutput.cpp b/lib/Frontend/PrintPreprocessedOutput.cpp
index d0aef2918c..00ab3c3176 100644
--- a/lib/Frontend/PrintPreprocessedOutput.cpp
+++ b/lib/Frontend/PrintPreprocessedOutput.cpp
@@ -164,11 +164,11 @@ void PrintPPOutputPPCallbacks::WriteLineInfo(unsigned LineNo,
   // Emit #line directives or GNU line markers depending on what mode we're in.
   if (UseLineDirective) {
     OS << "#line" << ' ' << LineNo << ' ' << '"';
-    OS.write(&CurFilename[0], CurFilename.size());
+    OS.write(CurFilename.data(), CurFilename.size());
     OS << '"';
   } else {
     OS << '#' << ' ' << LineNo << ' ' << '"';
-    OS.write(&CurFilename[0], CurFilename.size());
+    OS.write(CurFilename.data(), CurFilename.size());
     OS << '"';
 
     if (ExtraLen)
diff --git a/test/Preprocessor/print_line_empty_file.c b/test/Preprocessor/print_line_empty_file.c
new file mode 100644
index 0000000000..333896ee43
--- /dev/null
+++ b/test/Preprocessor/print_line_empty_file.c
@@ -0,0 +1,12 @@
+// RUN: %clang -E %s | FileCheck %s
+
+#line 21 ""
+int foo() { return 42; }
+
+#line 4 "bug.c" 
+int bar() { return 21; }
+
+// CHECK: # 21 ""
+// CHECK: int foo() { return 42; }
+// CHECK: # 4 "bug.c"
+// CHECK: int bar() { return 21; }