Vitis System Compilation mode can also be used with standard Vitis kernels (.xo) and the application acceleration design flow. Therefore, you can use VSC with Vitis HLS C++ kernels, as described in Vitis High-Level Synthesis User Guide (UG1399), and RTL kernels, as described in Vitis Unified Software Platform Documentation: Application Acceleration Development (UG1393).
Given a VSC accelerator code, sc_acc.cpp, and a Vitis kernel, kernel.xo, the following would be the command lines required to build the project:
v++ -c sc_acc.cpp -o sc_acc.o v++ -l sc_acc.o kernel.xo -o hw.xclbin # also produces hw.o g++ -c host.cpp -o host.o g++ -l -o host.exe host.o sc_acc.o hw.o -lvpp_acc -lxrt_hw -lpthread
In the scenario as it has been described, the kernel.xo is already compiled. So, the VSC accelerator code (sc_acc.cpp) needs to be compiled as shown in the first
v++ command above. The output of this is the object
command recognizes the VSC accelerator code, and compiles it properly into the object
v++ --link command is then run to
link the .xo and .o files into the .xclbin. Notice
that this produces a hw.o file in addition to the
hw.xclbin file. The hw.o file is required
for compilation of the host application by the
command as is shown in the next steps.
g++ command compiles the host code,
and then links the various object files (host.o,
sc_acc.o, and hw.o) to produce the host.exe
executable. Notice the addition of the
vpp_acc and the
xrt_hw libraries to the
g++ command line as they are required for the linking process.
In a standard Vitis flow, using
native-XRT or OpenCL code, the user host code has to
explicitly load the .xclbin. In a mixed VSC-XO flow
the user host code can still load the .xclbin
explicitly, but is not required. Instead, the device-ID can be obtained by calling API
Buffers objects can be easily passed between the native XRT and VSC APIs. The two possible buffer transfer scenarios are described in the following sections.