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

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Lex/PPLexerChange.cpp b/clang/lib/Lex/PPLexerChange.cpp
index 5a589d6a17b..1c0cd563683 100644
--- a/clang/lib/Lex/PPLexerChange.cpp
+++ b/clang/lib/Lex/PPLexerChange.cpp
@@ -46,6 +46,12 @@ bool Preprocessor::isInPrimaryFile() const {
   });
 }
 
+bool Preprocessor::isInMainFile() const {
+  if (IsFileLexer())
+    return IncludeMacroStack.size() == 0;
+  return true;
+}
+
 /// getCurrentLexer - Return the current file lexer being lexed from.  Note
 /// that this ignores any potentially active macro expansions and _Pragma
 /// expansions going on at the time.