[libc] add test formatting rules

[michaelrj]

Summary

Add an invocation of clang tidy that applies to the tests for LLVM-libc.
The next patch will include the actual changes made by applying the new
formatting rules.

[sivachandra]

libc/test/src/string/memory_utils/.clang-tidy

1

I would actually vote for not adding any of these .clang-tidy files in this round. Just the CMake change to run clang-tidy for the tests should be sufficient as it will then use the main .clang-tidy file which is good enough to start with. WDYT?

[michaelrj]

libc/test/src/string/memory_utils/.clang-tidy

1

The problem is that each of these .clang-tidy files have reasons behind them. The other two are there because those files are matching external interfaces that we can't change, and so reformatting them is unhelpful. This file is because clang-tidy will fully crash if it tries to format utils_test.cpp, for which I filed a bug here: https://github.com/llvm/llvm-project/issues/52825. I can remove the other two files, although it will cause a lot of log spam from the formatter being confused about functions with names that don't match our formatting, but are defined by gtest or MPFR (e.g. addTest). On the other hand, there's already a lot of log spam from the files that also implement the gtest interface, but are not in that folder (e.g. TmMatcher).

[sivachandra]

libc/test/src/string/memory_utils/.clang-tidy

1

Lets do it this way then. Can you land it https://reviews.llvm.org/D116127 as a separate cleanup patch? We will play with this change after that to better understand how to proceed.

[michaelrj]

libc/test/src/string/memory_utils/.clang-tidy

1

SGTM

libc/cmake/modules/LLVMLibCTestRules.cmake

add_custom_command(
     COMMAND $<TARGET_FILE:${fq_target_name}>
   )
   if(LIBC_UNITTEST_SUITE)
     add_dependencies(
       ${LIBC_UNITTEST_SUITE}
       ${fq_target_name}
     )
   endif()
+
+  if(LLVM_LIBC_ENABLE_LINTING)
+    set(lint_timestamp "${CMAKE_CURRENT_BINARY_DIR}/.${target_name}.__lint_timestamp__")
+    add_custom_command(
+      OUTPUT ${lint_timestamp}
+      # --quiet is used to surpress warning statistics from clang-tidy like:
+      #     Suppressed X warnings (X in non-user code).
+      # There seems to be a bug in clang-tidy where by even with --quiet some
+      # messages from clang's own diagnostics engine leak through:
+      #     X warnings generated.
+      # Until this is fixed upstream, we use -fno-caret-diagnostics to surpress
+      # these.
+      COMMAND $<TARGET_FILE:clang-tidy>
+              "--extra-arg=-fno-caret-diagnostics" --quiet
+              "--export-fixes=${CMAKE_CURRENT_BINARY_DIR}/${target_name}.yaml"
+              # Path to directory containing compile_commands.json
+              -p ${PROJECT_BINARY_DIR}
+              ${LIBC_UNITTEST_SRCS}
+      # See above: this might be a second invocation of clang-tidy depending on
+      # the conditions above.
+      ${restrict_system_headers_check_invocation}
+      # We have two options for running commands, add_custom_command and
+      # add_custom_target. We don't want to run the linter unless source files
+      # have changed. add_custom_target explicitly runs everytime therefore we
+      # use add_custom_command. This function requires an output file and since
+      # linting doesn't produce a file, we create a dummy file using a
+      # crossplatform touch.
+      COMMAND "${CMAKE_COMMAND}" -E touch ${lint_timestamp}
+      COMMENT "Linting... ${target_name}"
+      DEPENDS clang-tidy ${internal_target_name} ${LIBC_UNITTEST_SRCS}
+      WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+    )
+
+    add_custom_target(${fq_target_name}.__lint__
+      DEPENDS ${lint_timestamp})
+    add_dependencies(lint-libc ${fq_target_name}.__lint__)
+    add_dependencies(${fq_target_name} ${fq_target_name}.__lint__)
+  endif()
+
 endfunction(add_libc_unittest)
 
 function(add_libc_testsuite suite_name)
   add_custom_target(${suite_name})
   add_dependencies(check-llvmlibc ${suite_name})
 endfunction(add_libc_testsuite)
 
 function(add_libc_exhaustive_testsuite suite_name)

libc/test/src/string/memory_utils/.clang-tidy

+# temporary, this folder was crashing clang-tidy. I'm working on reporting the bug.
+InheritParentConfig: false
+Checks: '-*,llvmlibc-*'
+HeaderFilterRegex: '.*'
+WarningsAsErrors: 'llvmlibc-*'
+CheckOptions:
+  - key:             llvmlibc-restrict-system-libc-headers.Includes
+    value:           '-*, linux/*, asm/*.h, asm-generic/*.h'

libc/utils/MPFRWrapper/.clang-tidy

+InheritParentConfig: false
+Checks: '-*,llvmlibc-*'
+HeaderFilterRegex: '.*'
+WarningsAsErrors: 'llvmlibc-*'
+CheckOptions:
+  - key:             llvmlibc-restrict-system-libc-headers.Includes
+    value:           '-*, linux/*, asm/*.h, asm-generic/*.h'

libc/utils/UnitTest/.clang-tidy

+InheritParentConfig: false
+Checks: '-*,llvmlibc-*'
+HeaderFilterRegex: '.*'
+WarningsAsErrors: 'llvmlibc-*'
+CheckOptions:
+  - key:             llvmlibc-restrict-system-libc-headers.Includes
+    value:           '-*, linux/*, asm/*.h, asm-generic/*.h'