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triSYCL / sycl

SYCL for Vitis: Experimental fusion of triSYCL with Intel SYCL oneAPI DPC++ up-streaming effort into Clang/LLVM
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fPIC error when compiling as shared library #212

Closed gogo2 closed 1 year ago

gogo2 commented 1 year ago

Some background

First of all, sorry for creating so many issues recently. I'm working on a paper about the project I mentioned some time ago in https://github.com/triSYCL/sycl/issues/123 (now fully finished with about 1000 lines of accelerated code and 7 kernels implemented as callable objects) and having the algorithm compiled and working on FPGA would be a very nice addition. I hope that my reports give a comprehensive description of the issues I have and they somehow contribute to overall development and improvement of your SYCL implementation.

Problem description

This time, when I try to compile sycl-accelerated part as a shared library (and consequently with -fPIC flag) , during the _asm_ir step I get a llvm-as error with message: assembly parsed, but does not verify as correct! invalid behavior operand in module flag (unexpected constant) i32 8

I have found out that that the direct cause is the line containing !{i32 8, !"PIC Level", i32 2} in *_kernels_linked.opt.ll file. Changing the above to !{i32 7, !"PIC Level", i32 2} helps, library compiles successfully and hw_emu gives correct results, but i'm not an llvm expert by any means and I have no idea what is the correct value and maybe it is just luck that it worked so far.

Setup

Ralender commented 1 year ago

First of all, sorry for creating so many issues recently. I'm working on a paper about the project I mentioned some time ago in https://github.com/triSYCL/sycl/issues/123 (now fully finished with about 1000 lines of accelerated code and 7 kernels implemented as callable objects) and having the algorithm compiled and working on FPGA would be a very nice addition. I hope that my reports give a comprehensive description of the issues I have and they somehow contribute to overall development and improvement of your SYCL implementation.

no worries I know this tool is far from perfect and you are helping making it better. I will look into this issue.

Ralender commented 1 year ago

this https://github.com/triSYCL/sycl/pull/213 should fix your issue.

since compiling in PIC is useless for device code. I edited the driver to not compile device code in PIC mode.

gogo2 commented 1 year ago

this #213 should fix your issue.

since compiling in PIC is useless for device code. I edited the driver to not compile device code in PIC mode.

I confirm. Thanks again!