[cmake] Add llvm-locstats to LLVM_TEST_DEPENDS

[dstenb]

Summary

Make sure that llvm-locstats is updated before running lit tests even
when it's not an explicit target.

[djtodoro]

Good change! It sound reasonable to me.

[DavidSpickett]

How is this change supposed to interact with LLVM_BUILD_TOOLS?
"LLVM_BUILD_TOOLS: Build the LLVM tools. If OFF, just generate build targets."

We have a downstream build that sets this OFF, then builds llvm-mc only. You can reproduce the same thing with upstream llvm:

$ cmake -G Ninja ../llvm-project/llvm/ -DLLVM_BUILD_TOOLS=OFF

CMake Error at cmake/modules/AddLLVM.cmake:1457 (add_dependencies):
  The dependency target "llvm-locstats" of target "check-llvm-tools-llvm-rc"
  does not exist.
Call Stack (most recent call first):
  cmake/modules/AddLLVM.cmake:1509 (add_lit_target)
  test/CMakeLists.txt:179 (add_lit_testsuites)
<repeats for lots of targets>

Perhaps build tools isn't defining the targets as it claims.

[DavidSpickett]

Posted a fix here: https://reviews.llvm.org/D71695

Please review.

[dstenb]

In D71611#1790894, @DavidSpickett wrote:

How is this change supposed to interact with LLVM_BUILD_TOOLS?
"LLVM_BUILD_TOOLS: Build the LLVM tools. If OFF, just generate build targets."

We have a downstream build that sets this OFF, then builds llvm-mc only. You can reproduce the same thing with upstream llvm:

$ cmake -G Ninja ../llvm-project/llvm/ -DLLVM_BUILD_TOOLS=OFF

CMake Error at cmake/modules/AddLLVM.cmake:1457 (add_dependencies):
  The dependency target "llvm-locstats" of target "check-llvm-tools-llvm-rc"
  does not exist.
Call Stack (most recent call first):
  cmake/modules/AddLLVM.cmake:1509 (add_lit_target)
  test/CMakeLists.txt:179 (add_lit_testsuites)
<repeats for lots of targets>

Perhaps build tools isn't defining the targets as it claims.

Oh, okay!

I see that all other utils/ dependencies in LLVM_TEST_DEPENDS are C++ programs, so they use add_llvm_utility in their CMakeLists.txt, instead of a custom target as is used for llvm-locstats.

I'm unfortunately not very well-versed with LLVM's build system, so I don't have any good fix for this at the moment. I guess that breaking cmake invocations is worse than the issue this patch attempted to fix, so feel free to revert this, or let me know and I'll do that.

[DavidSpickett]

No that's fine, no change needed. I think you just uncovered an issue with the way llvm-locstats was defined (or not as the case was).

llvm/test/CMakeLists.txt

set(LLVM_TEST_DEPENDS
           llvm-extract
           llvm-isel-fuzzer
           llvm-ifs
           llvm-install-name-tool
           llvm-jitlink
           llvm-lib
           llvm-link
           llvm-lipo
+          llvm-locstats
           llvm-lto2
           llvm-mc
           llvm-mca
           llvm-modextract
           llvm-mt
           llvm-nm
           llvm-objcopy
           llvm-objdump