r368280 - [clang-format] fix crash involving invalid preprocessor line

[Krasimir Georgiev via cfe-commits]

Author: krasimir
Date: Thu Aug  8 04:56:18 2019
New Revision: 368280

URL: http://llvm.org/viewvc/llvm-project?rev=368280&view=rev
Log:
[clang-format] fix crash involving invalid preprocessor line

Summary:
This (invalid) fragment is crashing clang-format:
```
#if 1
int x;
#elif
int y;
#endif
```

The reason being that the parser expects a token after `#elif`, and the
subsequent parsing of the next line does not check if `CurrentToken` is null.

Reviewers: gribozavr

Reviewed By: gribozavr

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65940

Modified:
    cfe/trunk/lib/Format/TokenAnnotator.cpp
    cfe/trunk/unittests/Format/FormatTest.cpp

Modified: cfe/trunk/lib/Format/TokenAnnotator.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/TokenAnnotator.cpp?rev=368280&r1=368279&r2=368280&view=diff
==============================================================================
--- cfe/trunk/lib/Format/TokenAnnotator.cpp (original)
+++ cfe/trunk/lib/Format/TokenAnnotator.cpp Thu Aug  8 04:56:18 2019
@@ -1099,6 +1099,8 @@ private:
 
 public:
   LineType parseLine() {
+    if (!CurrentToken)
+      return LT_Invalid;
     NonTemplateLess.clear();
     if (CurrentToken->is(tok::hash))
       return parsePreprocessorDirective();

Modified: cfe/trunk/unittests/Format/FormatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Format/FormatTest.cpp?rev=368280&r1=368279&r2=368280&view=diff
==============================================================================
--- cfe/trunk/unittests/Format/FormatTest.cpp (original)
+++ cfe/trunk/unittests/Format/FormatTest.cpp Thu Aug  8 04:56:18 2019
@@ -3087,6 +3087,15 @@ TEST_F(FormatTest, IndentPreprocessorDir
                "#endif\n"
                "#endif\n",
                Style);
+  // Don't crash if there is an #elif directive without a condition.
+  verifyFormat("#if 1\n"
+               "int x;\n"
+               "#elif\n"
+               "int y;\n"
+               "#else\n"
+               "int z;\n"
+               "#endif",
+               Style);
   // FIXME: This doesn't handle the case where there's code between the
   // #ifndef and #define but all other conditions hold. This is because when
   // the #define line is parsed, UnwrappedLineParser::Lines doesn't hold the