What C++ standard does the current ROSE 'develop' branch support?

[bartlettroscoe]

What C++ standard does the current ROSE 'develop' branch and does it support the entire C++ standard? For example, does ROSE 'develop' support the full C++17 language standard? According to the latest 'develop' README.md at:

• https://github.com/rose-compiler/rose/blob/33377c77b4e92baeeda78a4a334122be1ebc4127/README.md#supported-compilers

it says:

When ROSE is configured with c/c++ support it is required to download an EDG binary ... so for fully supported version use GCC 7 through 10.

But GNU g++ 10 should support mostly all of C++17 (see here).

But other documentation at:

• http://rosecompiler.org/ROSE_HTML_Reference/index.html

says:

C++ (e.g., C++98 and C++11)

Does that mean it only supports up to C++11 or is "C++11" just mean "modern C++"?

[aaronsimon29]

This response is applicable to the most current version of ROSE (v0.11.145.237). We have switched to EDG 6.5 recently, so older versions may have less support; please make sure you are using the most recent version. ROSE has full support for C++14, and moderate support for C++17, which we are looking to improve over the next few months. Most of the issues ROSE has with C++17 are due to the GNU STL headers, which ROSE has difficulties compiling because of their use of unsupported built-ins. ROSE also has some support for C++20 features, but not the entire standard. ROSE is tested weekly using the Plumhall testsuite to check its support for all C and C++ standards.

[bartlettroscoe]

@aaronsimon29, thanks for the response! What is the fastest way to se if ROSE supports the C++ being used in, for example, Trilinos? (Trilinos includes Kokkos which requires several C++17 features and soon will require C++20 features.) For example, could we use:

• https://github.com/rose-compiler/rose/wiki/ROSE-based-tools#identity-translator

to read in and write out all of the Trilinos C & C++ source files and then compile and run the code to see if all of the code and tests build and pass? I know we can't expect char-for-char matching but the regenerated C++ source code should build and run the same, correct?

How do you provide the exact context info when processing C++ source files (like with the clang-tidy -p option that pulls in info for the CMake-generated compile_commands.json file)? Can you point us to documentation for this?

[aaronsimon29]

1. Yes, the identityTranslator is a good choice for checking whether ROSE can compile something, since it is the most basic ROSE tool. ROSE passes the code it generates to the backend compiler by default, so you could simply replace all calls to the backend compiler in your build system with calls to identityTranslator, then run the build system and see where/if it fails. The code generated by the identityTranslator should have identical logic, though it will not look identical to the original code.

2. ROSE does not have support for using an external file to determine what flags to compile specific source files with. ROSE is typically given the context by replacing the calls to the backend compiler with calls to ROSE instead (e.g. g++ -c foo.cc -o foo.o <OTHER_FLAGS> becomes identityTranslator-c foo.cc -o foo.o <OTHER_FLAGS>).

[bartlettroscoe]

ROSE is typically given the context by replacing the calls to the backend compiler with calls to ROSE instead (e.g. g++ -c foo.cc -o foo.o <OTHER_FLAGS> becomes identityTranslator-c foo.cc -o foo.o <OTHER_FLAGS>).

@aaronsimon29, thanks for the response!

Okay, so we would need an equivalent tool like run-clang-tidy that reads in the compile_commands.json file and extracts the command-line arguments to run on each object file target. Has anyone ever done such a thing with ROSE that you know of?

[aaronsimon29]

I don’t know of any script that does exactly what you’re looking for, but similar things have been done. For instance, we use a Python script to test ROSE’s ability to compile all of the tests in the Plumhall testsuite. While that script doesn’t get its flags from a JSON file, it does call ROSE on a multitude of files, and analyses the results for each file. I think it would be possible to write a script that does what you suggest.

[bartlettroscoe]

My guess one could just copy:

• https://github.com/llvm/llvm-project/blob/main/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py

and modify it for usage with ROSE (or any tool that grabs compiler options and substitutes the compiler).

For example, you can see it reads from the CMake output file compile_commands.json here:

• https://github.com/llvm/llvm-project/blob/f4d599cda90aa06d1e1a95474a0ee3a4053e77dd/clang-tools-extra/clang-tidy/tool/run-clang-tidy.py#L451

[bartlettroscoe]

We are going to give the outline tool a try, and that will answer the question of if ROSE supports -std=c++17 with GNU g++10 with our target Kokkos & Trilinos source code. (And we will try an older version of Kokkos + Trilinos that works with -std=c++14 as well.)

@aaronsimon29, thanks for answering our questions!