[SYCL][ESIMD][EMU] URL for pre-built CM_EMU library package

[dongkyunahn-intel]

• For ESIMD_EMULATOR, URL for pre-built CM_EMU library package is
  provided with 'ESIMD_EMU_USE_PREBUILT_CM_PACKAGE' cmake argument

[kbobrovs]

I would suggest the following overall logic below. When running CMake, variables starting with USE_ can be overridden from the command line.

DEFAULT_LIBCM_PREBUILT_PACKAGE=github.com/.../xxx.tgz
DEFAULT_LIBCM_SOURCES=github.com/.../cm-cpu-emulation.it

if (USE_DEFAULT_LIBCM_SOURCES) {
  # USE_DEFAULT_LIBCM_SOURCES is a boolean flag
  download DEFAULT_LIBCM_SOURCES and build it
  assert(!USE_LIBCM_PREBUILT_PACKAGE && !USE_LIBCM_SOURCES)
} else if (USE_LIBCM_SOURCES) {
  # USE_LIBCM_SOURCES is a directory
  treat USE_LIBCM_SOURCES as a local source directory, and build it
  assert(!USE_LIBCM_PREBUILT_PACKAGE)
} else {
  ACTUAL_LIBCM_PREBUILT_PACKAGE=$DEFAULT_LIBCM_PREBUILT_PACKAGE
  if (USE_LIBCM_PREBUILT_PACKAGE) {
    ACTUAL_LIBCM_PREBUILT_PACKAGE=$USE_LIBCM_PREBUILT_PACKAGE
  }
  use libCM binaries pointed to by ACTUAL_LIBCM_PREBUILT_PACKAGE
}

[dongkyunahn-intel]

Unrelated failures

SYCL / Linux / OCL GEN9 LLVM Test Suite

Failed Tests (1):
  SYCL :: DiscardEvents/invalid_event.cpp

SYCL / Linux / OCL x64 LLVM Test Suite

Failed Tests (1):
  SYCL :: KernelAndProgram/undefined-symbol.cpp

[kbobrovs]

ExternalProject_Add seems not the right tool for downloading pre-built packages, AFAIU, it is for adding external CMakeProjects and build them from source. Please check

[dongkyunahn-intel]

FetchContent_* functions can be used for downloading archives. However, it seems that using the functions requires extra steps for CM_EMU as the downloaded library package is used for both toolchain build and kernel compilation. I would like to keep this part as it is with TODO comments due to urgency of this change set. CMake for LevelZero PI also uses ExternalProject_Add for LevelZero module and already has TODO comment for FetchContent -

llvm/sycl/plugins/level_zero/CMakeLists.txt

Line 30 in 863383b

#TODO: Replace ExternalProject with FetchContent for better maintainance and

.

[kbobrovs]

OK, please add a TODO then too

[kbobrovs]

I suggest to factor out the MSVC check and do it once (there is another one at line 50).
More than that, I think it is better to check if you are running on Windows, in which case bail out. Then the MSVC check should be replaced with single platform/OS check.

[kbobrovs]

I suggest to add a message here so that users can see what USE_* variables are available to adjust the emulator build, something like
"Neither of USE_DEFAULT_CM_EMU_SOURCE, USE_LOCAL_CM_EMU_SOURCE, USE_CM_EMU_PREBUILT_PACKAGE is set, using prebuilt libCM from ${ACTUAL_CM_EMU_PREBUILT_PACKAGE}"

[dongkyunahn-intel]

Unrelated failure from Jenkins/Precommit.

SYCL :: Basic/sampler/sampler.cpp

[kbobrovs]

@smaslov-intel , could you please review/approve?

[dongkyunahn-intel]

@kbobrovs , I updated this PR as new version of open-source CM_EMU library was released. Only download URL changed after your approval.

@smaslov-intel , would you review & approve this PR?

[dongkyunahn-intel]

Unrelated failure from Jenkins/Precommit

SYCL :: Basic/queue/release.cpp

[kbobrovs]

@smaslov-intel , please review & approve this PR

[smaslov-intel]

Is it documented anywhere? Is it set from anywhere, e.g. buildbot/congigure.py?

[dongkyunahn-intel]

I need to look up, but @pvchupin confirmed that this is typo. #5799 (comment)

[pvchupin]

My understanding it's initialized at this specific point. Everything configure.py is doing is adding esimd_emulator to SYCL_ENABLE_PLUGINS under the switch.
I'm not sure if we are using SYCL_BUILD_PI_ESIMD_EMULATOR anywhere, but it seems there are a few occurrences in in LIT infra.