[clang-tidy] Add CLANG_TIDY_CONFUSABLE_CHARS_GEN cmake setting to avoid building when cross compiling

[mstorsjo]

Summary

This is similar to the LLVM_TABLEGEN, CLANG_TABLEGEN and CLANG_PSEUDO_GEN settings.

[mstorsjo]

As the name of the tool becomes somewhat public and stable at this point, feel free to suggest shorter/neater names in D129798 too.

[mstorsjo]

Ping @serge-sans-paille @sammccall - does this seem reasonable, and would you like to tweak the name of the tool before cementing it into a public cmake option (that at least I would be setting while cross compiling)?

[sammccall]

Mechanics definitely seem reasonable.

I don't have a strong opinion about the name. I don't find it very clear, the missing info being that it's part of clang-tidy and it relates to confusable unicode characters, but clang-tidy-make-confusable-characters-table is probably too much of a mouthful.

I'd be tempted by clang-tidy-confusable-chars-gen or so but I'm really just painting the bikeshed at this point - up to you.

[mstorsjo]

In D129799#3681524, @sammccall wrote:

I'd be tempted by clang-tidy-confusable-chars-gen or so but I'm really just painting the bikeshed at this point - up to you.

That sounds like a clearer name to me, thanks! I’ll update D129798 and this patch with that name, run some test builds with it, push them, and then file backport requests for them, as they missed the branch.

[mstorsjo]

Updated with the new tool name, and renamed the cmake variable accordingly

[sammccall]

clang-tools-extra/clang-tidy/misc/CMakeLists.txt

13

Should make_confusable_table and make_confusable_table_target also be renamed?

[trcrsired]

Hi i have a question. Does llvm provide a general toggle to set all those things with a directory? It becomes unmanagable since the end of llvm 15 for Canadian compilation.

like LLVM_NATIVE_TOOL_DIR some thing like that?

BTW how to force LLVM to install all of them. It is just ridiculous why llvm does not install them by default. I need Canadian compilation all the time.

[mstorsjo]

In D129799#3689044, @trcrsired wrote:

Hi i have a question. Does llvm provide a general toggle to set all those things with a directory? It becomes unmanagable since the end of llvm 15 for Canadian compilation.

like LLVM_NATIVE_TOOL_DIR some thing like that?

Not that I know of, but that would indeed be quite convenient - sounds like a good idea to me.

clang-tools-extra/clang-tidy/misc/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   FrontendOpenMP
   Support
   )
 
-if(LLVM_USE_HOST_TOOLS)
+set(CLANG_TIDY_CONFUSABLE_CHARS_GEN "clang-tidy-confusable-chars-gen" CACHE
+  STRING "Host clang-tidy-confusable-chars-gen executable. Saves building if cross-compiling.")
+
+if(NOT CLANG_TIDY_CONFUSABLE_CHARS_GEN STREQUAL "clang-tidy-confusable-chars-gen")
+  set(make_confusable_table ${CLANG_TIDY_CONFUSABLE_CHARS_GEN})
+  set(make_confusable_table_target ${CLANG_TIDY_CONFUSABLE_CHARS_GEN})
+elseif(LLVM_USE_HOST_TOOLS)
   build_native_tool(clang-tidy-confusable-chars-gen make_confusable_table)
   set(make_confusable_table_target "${make_confusable_table}")
 else()
   set(make_confusable_table $<TARGET_FILE:clang-tidy-confusable-chars-gen>)
   set(make_confusable_table_target clang-tidy-confusable-chars-gen)
 endif()
 
 add_subdirectory(ConfusableTable)