Allow for unfinished #if blocks in preambles
Previously, a preamble only included #if blocks (and friends like
ifdef) if there was a corresponding #endif before any declaration or
definition. The problem is that any header file that uses include guards
will not have a preamble generated, which can make code-completion very
slow.
To prevent errors about unbalanced preprocessor conditionals in the
preamble, and unbalanced preprocessor conditionals after a preamble
containing unfinished conditionals, the conditional stack is stored
in the pch file.
This fixes PR26045.
Differential Revision: http://reviews.llvm.org/D15994
llvm-svn: 304207
diff --git a/clang/test/Lexer/preamble2.c b/clang/test/Lexer/preamble2.c
new file mode 100644
index 0000000..499a9a2
--- /dev/null
+++ b/clang/test/Lexer/preamble2.c
@@ -0,0 +1,19 @@
+// Preamble detection test: header with an include guard.
+#ifndef HEADER_H
+#define HEADER_H
+#include "foo"
+int bar;
+#endif
+
+// This test checks for detection of the preamble of a file, which
+// includes all of the starting comments and #includes.
+
+// RUN: %clang_cc1 -print-preamble %s > %t
+// RUN: echo END. >> %t
+// RUN: FileCheck < %t %s
+
+// CHECK: // Preamble detection test: header with an include guard.
+// CHECK-NEXT: #ifndef HEADER_H
+// CHECK-NEXT: #define HEADER_H
+// CHECK-NEXT: #include "foo"
+// CHECK-NEXT: END.