[PATCH] D93987: [ASTMatchers] Fix build when no targets are enabled

[Stephen Kelly via Phabricator via llvm-commits]

steveire added inline comments.


================
Comment at: llvm/cmake/modules/LLVM-Config.cmake:31
     set(omitted_targets ${LLVM_ALL_TARGETS})
-    list(REMOVE_ITEM omitted_targets ${LLVM_TARGETS_TO_BUILD})
+    if (LLVM_TARGETS_TO_BUILD)
+      list(REMOVE_ITEM omitted_targets ${LLVM_TARGETS_TO_BUILD})
----------------
aaron.ballman wrote:
> I'm not a CMake expert, so can you explain what effect this change has? From the documentation (and my own limited understanding of cmake), I would have expected this to be a noop -- if the list of elements is empty, nothing will get removed from `omitted_targets`, right?

You can reproduce the issue in a small testcase with this file:

```
set(omitted_targets one two three)

# Comment this to reproduce the failure
set(LLVM_TARGETS_TO_BUILD X86)

list(REMOVE_ITEM omitted_targets ${LLVM_TARGETS_TO_BUILD})

```

Run this after commenting the line:

```
$ cmake -P cmaketest.cmake
CMake Error at cmaketest.cmake:6 (list):
  list sub-command REMOVE_ITEM requires two or more arguments.
```



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D93987/new/

https://reviews.llvm.org/D93987