Hi Adi, On 31.03.23 14:35, Prasad, Adi wrote:
Rework lto-wrapper so that if the separate host process target is enabled, it finds and calls a mkoffload for the host architecture instead of looking for an offloading compiler’s mkoffload; then write a mkoffload tool for a separate host process.
Note that multiple offload targets are possible. For instance, on Debian/Ubuntu, 'gcc -v' shows: 'OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa' and lto-wrapper then cycles through those, finding the offloading compiler in $PATH/accel/<triple>/mkoffload Example: x86_64-none-linux-gnu/12.2.1/accel/amdgcn-amdhsa/mkoffload Thus, if you install it to 'x86_64-none-linux-gnu' and add it to OFFLOAD_TARGET_NAMES,* it will work; albeit, we probably want to have some special handling in gcc.cc to avoid host-process offloading by default and permit something like -foffload=host instead of having to specify -foffload=x86_64-none-linux-gnu (For those flags, see https://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html#index-foffload ) (* it is automatically when adding it to --enable-offload-targets=... when configuring the non-offloading compiler.)
3. Write a libgomp plugin for separate host processes 4. Document changes, certify Developer Certificate of Origin, produce a ChangeLog etc according tohttps://gcc.gnu.org/wiki/GettingStarted#Tutorials.2C_HOWTOsandhttps://gcc.gnu.org/contribute.html#patches
I think it would be useful to start posting patches early – such that they can be reviewed and discussed. Thus, this is not really the 4th and 5th item.
5. Submit to the mailing list and respond to any requests for changes
* * *
One thing I was wondering that I may be missing - the offloading docs state that the patch for adding the Intel MIC target have a “runtime offloading library” called Intel MIC. I haven’t been able to figure out the purpose of this (my best guess is it’s used to implement the libgomp plugin?), and whether it’s Intel-specific or needed for multiple targets.
There used to be Intel MIC support – which effectively only used a simulator, similar to what this project is about, but this time it is supposed to be generic and not as narrowly focused as the Intel MIC stub/simulator/target support. (Intel MIC support was removed.)
Finally, I was wondering if, having built and tested GCC, there are now any patches, tests, or docs that I can work on?
For offloading tests, see libgomp/testsuite/ for OpenMP and OpenACC - albeit for OpenMP, only those tests with 'omp target' actually use offloading, which can be hostfall back. They can be run as "make check-target-libgomp" (in the build dir) or by "cd x86_64-none-linux-gnu/libgomp; make check" – and specific tests can be run by setting, e.g., RUNTESTFLAGS="fortran.exp" or RUNTESTFLAGS="c.exp=target-11.c" or ... No quick idea for work items – maybe I get one – or Thomas does :-) Tobias ----------------- Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
