[PATCH] D121763: [cmake] Provide CURRENT_TOOLS_DIR centrally, replacing CLANG_TOOLS_DIR

[Sam McCall via Phabricator via cfe-commits]

sammccall added a comment.

In D121763#3385492 <https://reviews.llvm.org/D121763#3385492>, @hokein wrote:

> I think this patch is probably doing too much: 1. move CLANG_TOOLS_DIR to `configure_site_lit_cfg()` 2. rename.
>
> Can we split it into two patches? Land the first part, and the second part afterwards.

I don't think it can reasonably be called CLANG_TOOLS_DIR in that macro, the var has no connection to clang, and is set even when clang is not enabled.



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Comment at: llvm/cmake/modules/AddLLVM.cmake:1640
+  # Like LLVM_{TOOLS,LIBS}_DIR, but pointing at the build tree.
+  string(REPLACE "${CMAKE_CFG_INTDIR}" "${LLVM_BUILD_MODE}" CURRENT_TOOLS_DIR "${LLVM_RUNTIME_OUTPUT_INTDIR}")
+  string(REPLACE "${CMAKE_CFG_INTDIR}" "${LLVM_BUILD_MODE}" CURRENT_LIBS_DIR  "${LLVM_LIBRARY_OUTPUT_INTDIR}")
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hokein wrote:
> the change looks good, but I'm not sure the new name `CURRENT_TOOLS_DIR` is good, the name seems vague and not significantly better, since it always points at the build tree, maybe `LLVM_BUILD_DIR` or something similar? (The existing naming pattern looks like project-specific variables are prefixed with the project name `LLVM_`, `CLANG_`).
I agree the new name isn't good. (OTOH *all* these variables seem to have terrible names, so maybe it's just hard). But I think `LLVM_BUILD_DIR` is worse.

The name needs to communicate a lot of things:
1. that this is parallel to `LLVM_TOOLS_DIR`, and the successor to `$PROJECT_TOOLS_DIR`
2. that when LLVM and $PROJECT are built in different paths, this is the dir for $PROJECT and not for LLVM
3. That this is not a concrete directory, but may contain a `%(build_mode)%` placeholder
4. this variable is part of llvm-project, as opposed to some other CMake project it may be mixed with.

`CLANG_TOOLS_DIR` passes 1, 2, 4 (and fails 3, which is really hard).
`CURRENT_TOOLS_DIR` passes 1 & 2 only - it lacks namespacing.
`LLVM_BUILD_DIR` passes 4 only, I think - it's very unclear how it relates to `LLVM_TOOLS_DIR`.
`LLVM_CURRENT_TOOLS_DIR` would pass 1 and 4, but muddies the LLVM-vs-subproject distinction a bit.

What do you think of these criteria, are there some I missed? Any more name ideas? :-)


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Comment at: llvm/utils/gn/secondary/clang-tools-extra/clangd/test/BUILD.gn:31
 
     "CLANG_LIBS_DIR=",  # needed only for shared builds
+    "CURRENT_TOOLS_DIR=",
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hokein wrote:
> nit: this seems not needed anymore, as we have removed the `CLANG_LIBS_DIR` from the CMake file already.
Agree, I'll make a separate commit to avoid muddying the waters here.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D121763/new/

https://reviews.llvm.org/D121763