"Unable to lex string source code" error with "__has_include"

[johangill]

Describe the bug

After upgrading our compiler to gcc 11 I started to get parse error for some of my C++ code.
After some digging I traced the parse error to the <bits/c++config.h> system header.
With some more digging and simplification I reduced the problematic code to the one in the next part.

To Reproduce
Steps to reproduce the behavior:

1. Create a source file with this content:

#define DUMMY __has_include(<apa/bepa.h>)
#if DUMMY
#endif

2. Run the scanner.

Both the #define and the #if are necessary to reproduce the bug.

Expected behavior
No "unable to lex" parse error.

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Fedora 35 Linux
• SonarQube version: 8.9.8
• cxx plugin version: 2.0.7.3119
• sonar-scanner version: 4.7.0.2747
• gcc version: 11.3.1

Additional context

Patch for updating an existing test with this special case:

diff --git a/cxx-squid/src/test/resources/parser/own/C++17/has-include.cc b/cxx-squid/src/test/resources/parser/own/C++17/has-include.cc
index 3b906c91..5f7e35af 100644
--- a/cxx-squid/src/test/resources/parser/own/C++17/has-include.cc
+++ b/cxx-squid/src/test/resources/parser/own/C++17/has-include.cc
@@ -1,8 +1,12 @@
+#define EXISTS __has_include("i25/has_include.h")
+
 #ifdef __has_include                           // Check if __has_include is present
 #  if __has_include("i1/has_include.h")        // Check for a standard library
 #    include "i1/has_include1"
 #  elif __has_include("i2/has_include.h")      // Check for an experimental version
 #    include "i2/has_include"
+#  elif EXISTS
+#    include "i25/has_include.h"
 #  elif __has_include("i3/has_include.h")      // Try with an external library
 #    include "i3/has_include.h"
 #  else                                        // Not found at all

[guwirth]

Hi @johangill,

thanks for your feedback.

Regards,

[guwirth]

Hi,

definition of __has_include is: https://en.cppreference.com/w/cpp/preprocessor/include

Below it’s part of predefined macros of the cxx plugin __has_include=1:

sonar-cxx/cxx-squid/src/main/java/org/sonar/cxx/preprocessor/CxxPreprocessor.java

Line 610 in 8198eb7

"__has_include 1"

This seems to be wrong? Should be __has_include=__has_include?

There is a working test without macro expansion:

https://github.com/SonarOpenCommunity/sonar-cxx/blob/4d3d3338f09962fda444a64616629be3d4d4e569/cxx-squid/src/test/resources/parser/own/C%2B%2B17/has-include.cc

Not sure but you can try as a workaround:
https://github.com/SonarOpenCommunity/sonar-cxx/wiki/sonar.cxx.defines

sonar.cxx.defines=__has_include __has_include \n\

Regards,

[hakjo666]

I am colleague to @johangill and have been working with him on this issue on our side.

I tried the __has_include __has_include workaround, but sadly it does not work. I still get the lexer error.

[guwirth]

Hi @johangill,

seems to be a bigger issue and needs more time.

Regards,

[guwirth]

please test with https://github.com/SonarOpenCommunity/sonar-cxx/releases/tag/latest-snapshot

[hakjo666]

That version fixes the lex error.

I still get a lot of errors in the output like this though:

ERROR: preprocessor: undefined function-like macro '__has_include' assuming 0

It also complains about other compiler specific macros like __has_builtin, __has_cpp_attribute, and _GLIBCXX_HAS_BUILTIN.