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

Deep_P · 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

Owenoool · Answer

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

Owenoool · Answer

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

Deep_P · 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

Deep_P · Answer

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

hello_world example error with clean FPGA developer AMI (AL2)

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