[libc] Fix accidental inclusion of system libc headers.
Summary:
I found that because `--system-headers` flag was not included when running clang-tidy, errors produced from compiler provided headers were being suppressed. After passing this flag I realized that by including headers like stdint.h we were indirectly including headers from the system libc. To prevent this we pass `-ffreestanding`.
We don't want to pass `--system-headers` for all checks just the `llvmlibc-restrict-system-libc-headers` therefore we do a separate invocation of clang-tidy for this check.
Reviewers: abrachet, sivachandra
Reviewed By: sivachandra
Subscribers: mgorny, aheejin, tschuett, ecnelises, libc-commits
Tags: #libc-project
Differential Revision: https://reviews.llvm.org/D80178
GitOrigin-RevId: b2a485e37edf6415701c472d93afa7fa26dbcccb
diff --git a/cmake/modules/LLVMLibCObjectRules.cmake b/cmake/modules/LLVMLibCObjectRules.cmake
index e4bf157..2b7b537 100644
--- a/cmake/modules/LLVMLibCObjectRules.cmake
+++ b/cmake/modules/LLVMLibCObjectRules.cmake
@@ -144,7 +144,7 @@
${objects_target_name}
BEFORE
PRIVATE
- -fpie ${LLVM_CXX_STD_default}
+ -fpie ${LLVM_CXX_STD_default} -ffreestanding
)
target_include_directories(
${objects_target_name}
@@ -217,10 +217,18 @@
# 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
+ COMMAND $<TARGET_FILE:clang-tidy>
+ "--extra-arg=-fno-caret-diagnostics" --quiet
# Path to directory containing compile_commands.json
-p ${PROJECT_BINARY_DIR}
${ADD_ENTRYPOINT_OBJ_SRCS}
+ # We run restrict-system-libc-headers with --system-headers to prevent
+ # transitive inclusion through compler provided headers.
+ COMMAND $<TARGET_FILE:clang-tidy> --system-headers
+ --checks="-*,llvmlibc-restrict-system-libc-headers"
+ --quiet
+ -p ${PROJECT_BINARY_DIR}
+ ${ADD_ENTRYPOINT_OBJ_SRCS}
# 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
diff --git a/src/.clang-tidy b/src/.clang-tidy
index 6d6043a..29f78fd 100644
--- a/src/.clang-tidy
+++ b/src/.clang-tidy
@@ -3,4 +3,4 @@
WarningsAsErrors: 'llvmlibc-*'
CheckOptions:
- key: llvmlibc-restrict-system-libc-headers.Includes
- value: '-*, linux/*, asm/unistd.h'
+ value: '-*, linux/*, asm/*.h, asm-generic/*.h'
