hello_world example error with clean FPGA developer AMI (AL2)

Question

**Issue**:  
Seeing hello_world example failing while following instructions on the aws-fpga Repo.  
  
**Failure signature:**  
INFO: \[ConfigUtil 60-1032]  
emulation configuration file `emconfig.json` is created in ./_x.sw_emu.xilinx_aws-vu9p-f1_shell-v04261818_201920_2 directory  
cp -rf ./_x.sw_emu.xilinx_aws-vu9p-f1_shell-v04261818_201920_2/emconfig.json .  
XCL_EMULATION_MODE=sw_emu ./hello_world ./build_dir.sw_emu.xilinx_aws-vu9p-f1_shell-v04261818_201920_2/vadd.xclbin  
/home/ec2-user/src/project_data/aws-fpga/Vitis/examples/xilinx_2020.2/common/includes/xcl2/xcl2.cpp:50 Error calling err = cl::Platform::get(&platforms), error code is: -1001  
make\[1]: *** \[run] Error 1  
make\[1]: Leaving directory `/home/ec2-user/src/project_data/aws-fpga/Vitis/examples/xilinx_2020.2/hello_world'  
make: *** \[check] Error 2  
  
**Reproduce:**  
1. Launch EC2 instance with FPGA developer AMI (Amazon Linux 2) with Vitis 2020.2.  
2. Install XRT libraries following instructions here (https://github.com/aws/aws-fpga/blob/master/Vitis/docs/XRT_installation_instructions.md )  
3. Source setup script and try to compile SW_Emulation following instructions here (https://github.com/aws/aws-fpga/blob/master/Vitis/README.md )  
4. $ cd $VITIS_DIR/examples/xilinx/hello_world     // no error       
    $ make clean           // Seeing "basename: missing operand"                                                        
    $ make check TARGET=sw_emu DEVICE=$AWS_PLATFORM all    // Seeing failure signature above      
  
Greatly appreciate any input on why I'm seeing this failure. This is supposed to be a simple example? Please let me know if I have missed anything from the getting started guide. Thanks!  
  
Owenoool

Accepted Answer

The problem is that we have Vitis bundled libstdc++ in the LD_LIBRARY_PATH which is ABI incompatible with the update g++ on AL2. The fix is to use a libstdc++ that is ABI compatible with the system you are compiling on.  
  
By default g++ should look at /lib64 if you do not set an LD_LIBRARY_PATH. However, since it finds libstdc++ in the Vitis paths, it doesn't look for it there and fails.  
  
So your workaround should work without issue as it adds the library to the '/opt/xilinx/xrt/lib' path specified in LD_LIBRARY_PATH. We're also fixing the code not not include Vitis to LD_LIBRARY_PATH - and that should lead g++ to automatically find the library in /lib64. We'll release the fix soon.  
  
-Deep

Answer

Thank you Deep for the temporary fix! It is working for me now. Are there any pitfalls with this method?  
  
Owenoool

Answer

Hi owenool,  
  
We're looking at this issue with Xilinx and will provide an update on it by tomorrow.  
  
-Deep

Answer

Hi Owenool,  
  
It seems like there is some sort of an incompatibility between stdc++ symbols provided by Xilinx tools versus the ones on the AL2 AMI.  
I'm looking into this further, but for now could you run this and re-run your executable:

```
sudo cp /lib64/libstdc++.so.6 /opt/xilinx/xrt/lib/
```

Let me know if this doesn't work for you for now.  
  
Thanks,  
  
Deep

Answer

Thank you Deep for the temporary fix! It is working for me now. Are there any pitfalls with this method?  
  
Owenoool

hello_world example error with clean FPGA developer AMI (AL2)

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