Assert of 'clang_delta'

[JVApen]

Found on following code (t.cpp):

#include <variant>
#include <vector>
struct A {
         std::basic_string<wchar_t> m;
       };
        struct B {
         B(A a);
         std::variant<A> m;
       };
        struct C : B {
         using B::B;
       };
        void f() {
         std::vector<C> c{
     };
         c.push_back(C{
     A{
    }
     }
      );
       }

Launch script:

py -3.6 G:\llvm\build-cvise\cvise.py --clang-delta-std c++17 --n 1 --print-diff checkIfBugExists.bat t.cpp 

The error occurs within ClangPass::remove-unused-function

checkIfBugExists.bat

SET CVISE_BUG_DETECTED=0
SET CVISE_BUG_IRREPRODUCABLE=1
setlocal enableDelayedExpansion

echo "Current dir: %cd%"
echo "Copied file: %1"
C:\Path\To\LLVM_7_0_0\bin\clang-cl.exe /c /EHsc -w /std:c++17 t.cpp > compilation.out 2> compilation.err
if %ERRORLEVEL% EQU 0 (
   echo "Compilation success"
   exit /b %CVISE_BUG_IRREPRODUCABLE%
)
echo "Failed to compile"

findstr /r /c:"Wrote crash dump file" .\compilation.err
if %ERRORLEVEL% EQU 0 (
   echo "Found crash message"
   exit /b %CVISE_BUG_DETECTED%
) else (
   echo "Not found"
   exit /b %CVISE_BUG_IRREPRODUCABLE%
)

Callstack of delta.exe (Compiled with LLVM 10.0.0)

 	issue_debug_notification(message) Line 28	C++
 	__acrt_report_runtime_error(message) Line 154	C++
 	abort() Line 61	C++
 	common_assert_to_stderr<wchar_t>(expression, file_name, line_number) Line 187	C++
 	common_assert<wchar_t>(expression, file_name, line_number, return_address) Line 420	C++
 	_wassert(expression, file_name, line_number) Line 444	C++
>	RemoveUnusedFunction::doRewriting() Line 307	C++
 	RemoveUnusedFunction::HandleTranslationUnit(Ctx) Line 284	C++
 	clang::ParseAST(S, PrintStats, SkipFunctionBodies) Line 178	C++
 	TransformationManager::doTransformation(ErrorMsg, ErrorCode) Line 308	C++
 	main(argc, argv) Line 249	C++

Issue is in void RemoveUnusedFunction::doRewriting() where TheFunctionDecl seems to be nullptr. ToCounter is on -1.

[marxin]

Thanks for the report.
What version of LLVM do you use for CVise as a run-time library?
I can run the transformation with success:

$ clang_delta/clang_delta  --transformation=remove-unused-function  tc.C --counter=1 --std=c++17
#include <variant>
#include <vector>
struct A {
         std::basic_string<wchar_t> m;
       };
        struct B {
         B(A a);
         std::variant<A> m;
       };
        struct C : B {
         using B::B;
       };

Can you please attach output of pre-processed source file -E option for clang?

[JVApen]

I'm using LLVM 10, let me see if I can do so easily

[JVApen]

C:\path\to\build-cvise\clang_delta\Debug\clang_delta.exe --transformation=remove-unused-function
t.cpp.preprocessed.cpp --counter=1 --std=c++17
Warning: number of transformation instances exceeded
Assertion failed: RWBuf && "Empty RewriteBuffer!", file G:\llvm\cvise-master\clang_delta\Transformation.cpp, line 103

The file: t.cpp.preprocessed.zip

[marxin]

I'm sorry but I can't compile it on Linux:

clang++ x.ii -std=c++17
In file included from .\t.cpp:1:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\variant:9:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals.h:9:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals_core.h:253:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vcruntime.h:58:
In file included from c:\path\to\LLVM_10_0_0\lib\clang\10.0.0\include\vadefs.h:18:
c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vadefs.h:28:33: error: expected ';' after top level declarator
        typedef unsigned __int64 uintptr_t;
                                ^
In file included from .\t.cpp:1:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\variant:9:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals.h:9:
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals_core.h:253:
c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vcruntime.h:190:29: error: expected ';' after top level declarator
    typedef unsigned __int64 size_t;
                            ^
c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vcruntime.h:245:42: error: unknown type name 'size_t'
        template <typename _CountofType, size_t _SizeOfArray>
                                         ^

$ g++ x.ii -std=c++17 -fmax-errors=3
In file included from c:\path\to\LLVM_10_0_0\lib\clang\10.0.0\include\vadefs.h:18,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vcruntime.h:58,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals_core.h:253,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals.h:9,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\variant:9,
                 from .\t.cpp:1:
c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vadefs.h:28:34: error: expected initializer before ‘uintptr_t’
In file included from c:\path\to\LLVM_10_0_0\lib\clang\10.0.0\include\vadefs.h:18,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vcruntime.h:58,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals_core.h:253,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals.h:9,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\variant:9,
                 from .\t.cpp:1:
c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vadefs.h:112:18: error: expected initializer before ‘__va_start’
In file included from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals_core.h:253,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\yvals.h:9,
                 from c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\variant:9,
                 from .\t.cpp:1:
c:\path\to\Vs2019\VC\Tools\MSVC\14.24.28314\include\vcruntime.h:190:30: error: expected initializer before ‘size_t’
compilation terminated due to -fmax-errors=3.

[JVApen]

I guess you can replace __int64 by std::int64_t if you add the include

[marxin]

It will require much more adjustments. You can try it here:
https://godbolt.org/

[JVApen]

-fms-extensions does a lot, however, I seem to always have 32bit-64bit mismatches.
Any tips for me to debug it myself?

[marxin]

Maybe -m32 can help.
Anyway, that's more a LLVM issue than C-Vise issue. The code is invalid so it's partially understandable.