Do not complain about junk on the end of a #endif in a skipped block. Such junk

is permitted by all relevant language standards. Patch by Andy Gibbs!

llvm-svn: 158883

clang/lib/Lex/PPDirectives.cpp

@@ -317,7 +317,6 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
     } else if (Directive[0] == 'e') {
       StringRef Sub = Directive.substr(1);
       if (Sub == "ndif") {  // "endif"
-        CheckEndOfDirective("endif");
         PPConditionalInfo CondInfo;
         CondInfo.WasSkipping = true; // Silence bogus warning.
         bool InCond = CurPPLexer->popConditionalLevel(CondInfo);
@@ -326,9 +325,12 @@ void Preprocessor::SkipExcludedConditionalBlock(SourceLocation IfTokenLoc,
 
         // If we popped the outermost skipping block, we're done skipping!
         if (!CondInfo.WasSkipping) {
+          CheckEndOfDirective("endif");
           if (Callbacks)
             Callbacks->Endif(Tok.getLocation(), CondInfo.IfLoc);
           break;
+        } else {
+          DiscardUntilEndOfDirective();
         }
       } else if (Sub == "lse") { // "else".
         // #else directive in a skipping conditional.  If not in some other

clang/test/Preprocessor/disabled-cond-diags2.c

@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -Eonly -verify %s
+
+#if 0
+#if 1
+#endif junk // shouldn't produce diagnostics
+#endif
+
+#if 0
+#endif junk // expected-warning{{extra tokens at end of #endif directive}}
+
+#if 1 junk  // expected-error{{token is not a valid binary operator in a preprocessor subexpression}}
+#X          // shouldn't produce diagnostics (block #if condition not valid, so skipped)
+#else
+#X          // expected-error{{invalid preprocessing directive}}
+#endif
+
+#if 0
+// diagnostics should not be produced until final #endif
+#X
+#include
+#if 1 junk
+#else junk
+#endif junk
+#line -2
+#error
+#warning
+#endif junk // expected-warning{{extra tokens at end of #endif directive}}