PROCESSOR-SDK-J721S2: [TIARMCLANG]

Martin Rachor said:

if I want to do:

atomic_flag flag = ATOMIC_FLAG_INIT;

the compiler starts to complain

error: non-constant-expression cannot be narrowed from type 'int' to 'atomic_bool' (aka '_Atomic(bool)') in initializer list [-Wc++11-narrowing]
flag = ATOMIC_FLAG_INIT;

I can reproduce this diagnostic by writing this code in a C++ file.

/* fails.cpp */

#include <stdatomic.h>

atomic_flag flag = ATOMIC_FLAG_INIT;

Build it ...

$ tiarmclang -c fails.cpp
fails.cpp:5:20: error: non-constant-expression cannot be narrowed from type 'int' to 'atomic_bool' (aka '_Atomic(bool)')
      in initializer list [-Wc++11-narrowing]
atomic_flag flag = ATOMIC_FLAG_INIT;
                   ^~~~~~~~~~~~~~~~
C:\ti\compilers\ti-cgt-armllvm_3.2.0.LTS\lib\clang\15.0.7\include\stdatomic.h:161:28: note: expanded from macro
      'ATOMIC_FLAG_INIT'
#define ATOMIC_FLAG_INIT { 0 }
                           ^
fails.cpp:5:20: note: insert an explicit cast to silence this issue
atomic_flag flag = ATOMIC_FLAG_INIT;
                   ^~~~~~~~~~~~~~~~
C:\ti\compilers\ti-cgt-armllvm_3.2.0.LTS\lib\clang\15.0.7\include\stdatomic.h:161:28: note: expanded from macro
      'ATOMIC_FLAG_INIT'
#define ATOMIC_FLAG_INIT { 0 }
                           ^
1 error generated.

Add the option -x c to tell the compiler to process this same code as C, and not C++, then it builds clean.

$ tiarmclang -c -x c fails.cpp

Here is the C++ way to write it ...

/* works.cpp */

#include <atomic>

std::atomic_flag flag = ATOMIC_FLAG_INIT;

Regarding ...

Martin Rachor said:

I want to use atomic_flags on MCU2_0, but immediately, if I call the "atomic_flag_test_and_set_explicit" function,

the whole processor seems to crash.

I have to get with other experts.  I'll get back to you.

Thanks and regards,

-George

Hi Goerge,

I also tried the c++ version, because I'm in this context: but then i get the following issues:

/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:591:3: error: <atomic> is not supported on this single threaded system
# error <atomic> is not supported on this single threaded system
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:594:3: error: <atomic> is not implemented
# error <atomic> is not implemented
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:1535:13: error: use of undeclared identifier '__libcpp_thread_yield'
__libcpp_thread_yield();
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2496:23: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
__cxx_atomic_impl<_LIBCPP_ATOMIC_FLAG_TYPE> __a_;
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2500:17: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2503:17: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{return _LIBCPP_ATOMIC_FLAG_TYPE(true) == __cxx_atomic_load(&__a_, __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2507:46: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2510:46: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{return __cxx_atomic_exchange(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(true), __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2513:36: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2516:36: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{__cxx_atomic_store(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(false), __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2520:35: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}
^
/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include/c++/v1/atomic:2523:35: error: use of undeclared identifier '_LIBCPP_ATOMIC_FLAG_TYPE'
{__cxx_atomic_wait(&__a_, _LIBCPP_ATOMIC_FLAG_TYPE(__v), __m);}

Btw. this is my compiler call:

ti-cgt-armllvm_1.3.0.LTS/bin/tiarmclang  -DBUILD_MCU -DBUILD_MCU2_0 -DSOC_J721S2 -D_GNU_SOURCE -I/home/ubuntu/prjtools/tisdk/ti-cgt-armllvm_1.3.0.LTS/include -I/home/ubuntu/prjtools/tisdk/psdkqa/pdk/packages  -mfloat-abi=hard -mfpu=vfpv3-d16 -mcpu=cortex-r5 -march=armv7-r -fno-strict-aliasing -frtti -Oz   -std=gnu++11 -o foo.cpp.obj -c /foo.cpp

Thanks &Regards,

Martin

You use an older version of the compiler.  Is it practical for you to upgrade to the latest version 3.2.0.LTS?  That supports <atomic> .

Thanks and regards,

-George

Oh okay, I did not expect, that we have such an old version. Do you think it's feasible for this psdk version:

"ti-psdk-rtos-j721s2-08_05_00_11"

Regards,

Martin

You should use the compiler versions tested and documented to work with your SDK.  If that doesn't include version 3.2.0.LTS, then you can't use <atomic>.

Thanks and regards,

-George