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

[Haojian Wu via Phabricator via cfe-commits]

hokein added inline comments.


================
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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sammccall wrote:
> 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? :-)
> 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.

Thanks, these make sense, I were not aware of all of these and didn't get the full picture. I suppose it is being used for exposing various `config.{project}_tools_dir` variables for different tools (e.g. `config.clang_tools_dir`, `config.lldb_tools_dir` etc). 

> CURRENT_TOOLS_DIR passes 1 & 2 only - it lacks namespacing.

hmm, I think the new name is somewhat weak on 2 (particularly the PROJECT bit) -- the `Current` was unclear to me, I guess it means the current project right? I think it'd be better to have the PROJECT in the variable name, `LLVM_PROJECT_TOOLS_DIR` or shorter `PROJECT_TOOLS_DIR`. WDYT?



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

https://reviews.llvm.org/D121763