llvm-project/libc/cmake/modules/LLVMLibCObjectRules.cmake
Guillaume Chatelet b2a9ea4420 [libc] Apply no-builtin everywhere, remove unnecessary flags
Note, this is a re-submission of D125894 with `features = ["-header_modules"]`
added to the main BUILD.bazel file.

Some functions like `stpncpy` are implemented in terms of `memset` but are not
currently using `-fno-builtin-memset`. This is somewhat hidden by the fact that
we use `-ffreestanding` globally and that `-ffreestanding` implies
`-fno-builtin` for Clang.

This patch also removes `-mllvm -combiner-global-alias-analysis` that is Clang
specific and that does not bring substantial gains on modern processors.

Also we keep `-mllvm --tail-merge-threshold=0` for aarch64 in CMakeLists.txt
but we omit it in the Bazel config. This is because Bazel consumes the source
files directly and so it can use PGO to take optimal decisions locally.

Differential Revision: https://reviews.llvm.org/D126773
2022-06-01 13:34:36 +00:00

554 lines
18 KiB
CMake

set(OBJECT_LIBRARY_TARGET_TYPE "OBJECT_LIBRARY")
function(_get_common_compile_options output_var)
set(compile_options ${LIBC_COMPILE_OPTIONS_DEFAULT} ${ARGN})
if(NOT ${LIBC_TARGET_OS} STREQUAL "windows")
set(compile_options ${compile_options} -fpie -ffreestanding -fno-builtin)
endif()
if(LLVM_COMPILER_IS_GCC_COMPATIBLE)
list(APPEND compile_options "-fno-exceptions")
list(APPEND compile_options "-fno-unwind-tables")
list(APPEND compile_options "-fno-asynchronous-unwind-tables")
list(APPEND compile_options "-fno-rtti")
elseif(MSVC)
list(APPEND compile_options "/EHs-c-")
list(APPEND compile_options "/GR-")
endif()
set(${output_var} ${compile_options} PARENT_SCOPE)
endfunction()
# Rule which is essentially a wrapper over add_library to compile a set of
# sources to object files.
# Usage:
# add_object_library(
# <target_name>
# HDRS <list of header files>
# SRCS <list of source files>
# DEPENDS <list of dependencies>
# COMPILE_OPTIONS <optional list of special compile options for this target>
# FLAGS <optional list of flags>
function(create_object_library fq_target_name)
cmake_parse_arguments(
"ADD_OBJECT"
"" # No optional arguments
"CXX_STANDARD" # Single value arguments
"SRCS;HDRS;COMPILE_OPTIONS;DEPENDS;FLAGS" # Multivalue arguments
${ARGN}
)
if(NOT ADD_OBJECT_SRCS)
message(FATAL_ERROR "'add_object_library' rule requires SRCS to be specified.")
endif()
add_library(
${fq_target_name}
EXCLUDE_FROM_ALL
OBJECT
${ADD_OBJECT_SRCS}
${ADD_OBJECT_HDRS}
)
target_include_directories(
${fq_target_name}
PRIVATE
${LIBC_BUILD_DIR}/include
${LIBC_SOURCE_DIR}
${LIBC_BUILD_DIR}
)
_get_common_compile_options(compile_options ${ADD_OBJECT_COMPILE_OPTIONS})
target_compile_options(${fq_target_name} PRIVATE ${compile_options})
get_fq_deps_list(fq_deps_list ${ADD_OBJECT_DEPENDS})
if(SHOW_INTERMEDIATE_OBJECTS)
message(STATUS "Adding object library ${fq_target_name}")
if(${SHOW_INTERMEDIATE_OBJECTS} STREQUAL "DEPS")
foreach(dep IN LISTS ADD_OBJECT_DEPENDS)
message(STATUS " ${fq_target_name} depends on ${dep}")
endforeach()
endif()
endif()
if(fq_deps_list)
add_dependencies(${fq_target_name} ${fq_deps_list})
endif()
if(NOT ADD_OBJECT_CXX_STANDARD)
set(ADD_OBJECT_CXX_STANDARD ${CMAKE_CXX_STANDARD})
endif()
set_target_properties(
${fq_target_name}
PROPERTIES
TARGET_TYPE ${OBJECT_LIBRARY_TARGET_TYPE}
OBJECT_FILES "$<TARGET_OBJECTS:${fq_target_name}>"
CXX_STANDARD ${ADD_OBJECT_CXX_STANDARD}
DEPS "${fq_deps_list}"
FLAGS "${ADD_OBJECT_FLAGS}"
)
endfunction(create_object_library)
# Internal function, used by `add_object_library`.
function(expand_flags_for_object_library target_name flags)
cmake_parse_arguments(
"EXPAND_FLAGS"
"IGNORE_MARKER" # Optional arguments
"" # Single-value arguments
"DEPENDS;FLAGS" # Multi-value arguments
${ARGN}
)
list(LENGTH flags nflags)
if(NOT ${nflags})
create_object_library(
${target_name}
DEPENDS ${EXPAND_FLAGS_DEPENDS}
FLAGS ${EXPAND_FLAGS_FLAGS}
${EXPAND_FLAGS_UNPARSED_ARGUMENTS}
)
return()
endif()
list(POP_FRONT flags flag)
extract_flag_modifier(${flag} real_flag modifier)
if(NOT "${modifier}" STREQUAL "NO")
expand_flags_for_object_library(
${target_name}
"${flags}"
DEPENDS "${EXPAND_FLAGS_DEPENDS}" IGNORE_MARKER
FLAGS "${EXPAND_FLAGS_FLAGS}" IGNORE_MARKER
"${EXPAND_FLAGS_UNPARSED_ARGUMENTS}"
)
endif()
if("${real_flag}" STREQUAL "" OR "${modifier}" STREQUAL "ONLY")
return()
endif()
set(NEW_FLAGS ${EXPAND_FLAGS_FLAGS})
list(REMOVE_ITEM NEW_FLAGS ${flag})
get_fq_dep_list_without_flag(NEW_DEPS ${real_flag} ${EXPAND_FLAGS_DEPENDS})
# Only target with `flag` has `.__NO_flag` target, `flag__NO` and
# `flag__ONLY` do not.
if(NOT "${modifier}")
set(TARGET_NAME "${target_name}.__NO_${flag}")
else()
set(TARGET_NAME "${target_name}")
endif()
expand_flags_for_object_library(
${TARGET_NAME}
"${flags}"
DEPENDS "${NEW_DEPS}" IGNORE_MARKER
FLAGS "${NEW_FLAGS}" IGNORE_MARKER
"${EXPAND_FLAGS_UNPARSED_ARGUMENTS}"
)
endfunction(expand_flags_for_object_library)
function(add_object_library target_name)
cmake_parse_arguments(
"ADD_TO_EXPAND"
"" # Optional arguments
"" # Single value arguments
"DEPENDS;FLAGS" # Multi-value arguments
${ARGN}
)
get_fq_target_name(${target_name} fq_target_name)
if(ADD_TO_EXPAND_DEPENDS AND ("${SHOW_INTERMEDIATE_OBJECTS}" STREQUAL "DEPS"))
message(STATUS "Gathering FLAGS from dependencies for ${fq_target_name}")
endif()
get_fq_deps_list(fq_deps_list ${ADD_TO_EXPAND_DEPENDS})
get_flags_from_dep_list(deps_flag_list ${fq_deps_list})
list(APPEND ADD_TO_EXPAND_FLAGS ${deps_flag_list})
remove_duplicated_flags("${ADD_TO_EXPAND_FLAGS}" flags)
list(SORT flags)
if(SHOW_INTERMEDIATE_OBJECTS AND flags)
message(STATUS "Object library ${fq_target_name} has FLAGS: ${flags}")
endif()
expand_flags_for_object_library(
${fq_target_name}
"${flags}"
DEPENDS "${fq_deps_list}" IGNORE_MARKER
FLAGS "${flags}" IGNORE_MARKER
${ADD_TO_EXPAND_UNPARSED_ARGUMENTS}
)
endfunction(add_object_library)
set(ENTRYPOINT_OBJ_TARGET_TYPE "ENTRYPOINT_OBJ")
# A rule for entrypoint object targets.
# Usage:
# add_entrypoint_object(
# <target_name>
# [ALIAS|REDIRECTED] # Specified if the entrypoint is redirected or an alias.
# [NAME] <the C name of the entrypoint if different from target_name>
# SRCS <list of .cpp files>
# HDRS <list of .h files>
# DEPENDS <list of dependencies>
# COMPILE_OPTIONS <optional list of special compile options for this target>
# SPECIAL_OBJECTS <optional list of special object targets added by the rule `add_object`>
# FLAGS <optional list of flags>
# )
function(create_entrypoint_object fq_target_name)
cmake_parse_arguments(
"ADD_ENTRYPOINT_OBJ"
"ALIAS;REDIRECTED" # Optional argument
"NAME;CXX_STANDARD" # Single value arguments
"SRCS;HDRS;DEPENDS;COMPILE_OPTIONS;FLAGS" # Multi value arguments
${ARGN}
)
list(FIND TARGET_ENTRYPOINT_NAME_LIST ${ADD_ENTRYPOINT_OBJ_NAME} entrypoint_name_index)
if(${entrypoint_name_index} EQUAL -1)
add_custom_target(${fq_target_name})
set_target_properties(
${fq_target_name}
PROPERTIES
"ENTRYPOINT_NAME" ${ADD_ENTRYPOINT_OBJ_NAME}
"TARGET_TYPE" ${ENTRYPOINT_OBJ_TARGET_TYPE}
"OBJECT_FILE" ""
"OBJECT_FILE_RAW" ""
"DEPS" ""
"SKIPPED" "YES"
)
message(STATUS "Skipping libc entrypoint ${fq_target_name}.")
return()
endif()
if(ADD_ENTRYPOINT_OBJ_ALIAS)
# Alias targets help one add aliases to other entrypoint object targets.
# One can use alias targets setup OS/machine independent entrypoint targets.
list(LENGTH ADD_ENTRYPOINT_OBJ_DEPENDS deps_size)
if(NOT (${deps_size} EQUAL "1"))
message(FATAL_ERROR "An entrypoint alias should have exactly one dependency.")
endif()
list(GET ADD_ENTRYPOINT_OBJ_DEPENDS 0 dep_target)
get_fq_dep_name(fq_dep_name ${dep_target})
if(SHOW_INTERMEDIATE_OBJECTS)
message(STATUS "Adding entrypoint object ${fq_target_name} as an alias of"
" ${fq_dep_name}")
endif()
if(NOT TARGET ${fq_dep_name})
message(WARNING "Aliasee ${fq_dep_name} for entrypoint alias ${target_name} missing; "
"Target ${target_name} will be ignored.")
return()
endif()
get_target_property(obj_type ${fq_dep_name} "TARGET_TYPE")
if((NOT obj_type) OR (NOT (${obj_type} STREQUAL ${ENTRYPOINT_OBJ_TARGET_TYPE})))
message(FATAL_ERROR "The aliasee of an entrypoint alias should be an entrypoint.")
endif()
add_custom_target(${fq_target_name})
add_dependencies(${fq_target_name} ${fq_dep_name})
get_target_property(object_file ${fq_dep_name} "OBJECT_FILE")
get_target_property(object_file_raw ${fq_dep_name} "OBJECT_FILE_RAW")
set_target_properties(
${fq_target_name}
PROPERTIES
ENTRYPOINT_NAME ${ADD_ENTRYPOINT_OBJ_NAME}
TARGET_TYPE ${ENTRYPOINT_OBJ_TARGET_TYPE}
IS_ALIAS "YES"
OBJECT_FILE ""
OBJECT_FILE_RAW ""
DEPS "${fq_dep_name}"
FLAGS "${ADD_ENTRYPOINT_OBJ_FLAGS}"
)
return()
endif()
if(NOT ADD_ENTRYPOINT_OBJ_SRCS)
message(FATAL_ERROR "`add_entrypoint_object` rule requires SRCS to be specified.")
endif()
if(NOT ADD_ENTRYPOINT_OBJ_HDRS)
message(FATAL_ERROR "`add_entrypoint_object` rule requires HDRS to be specified.")
endif()
if(NOT ADD_ENTRYPOINT_OBJ_CXX_STANDARD)
set(ADD_ENTRYPOINT_OBJ_CXX_STANDARD ${CMAKE_CXX_STANDARD})
endif()
_get_common_compile_options(common_compile_options ${ADD_ENTRYPOINT_OBJ_COMPILE_OPTIONS})
set(internal_target_name ${fq_target_name}.__internal__)
set(include_dirs ${LIBC_BUILD_DIR}/include ${LIBC_SOURCE_DIR} ${LIBC_BUILD_DIR})
get_fq_deps_list(fq_deps_list ${ADD_ENTRYPOINT_OBJ_DEPENDS})
set(full_deps_list ${fq_deps_list} libc.src.__support.common)
if(SHOW_INTERMEDIATE_OBJECTS)
message(STATUS "Adding entrypoint object ${fq_target_name}")
if(${SHOW_INTERMEDIATE_OBJECTS} STREQUAL "DEPS")
foreach(dep IN LISTS ADD_OBJECT_DEPENDS)
message(STATUS " ${fq_target_name} depends on ${dep}")
endforeach()
endif()
endif()
add_library(
${internal_target_name}
# TODO: We don't need an object library for internal consumption.
# A future change should switch this to a normal static library.
EXCLUDE_FROM_ALL
OBJECT
${ADD_ENTRYPOINT_OBJ_SRCS}
${ADD_ENTRYPOINT_OBJ_HDRS}
)
target_compile_options(${internal_target_name} BEFORE PRIVATE ${common_compile_options})
target_include_directories(${internal_target_name} PRIVATE ${include_dirs})
add_dependencies(${internal_target_name} ${full_deps_list})
set_target_properties(
${internal_target_name}
PROPERTIES
CXX_STANDARD ${ADD_ENTRYPOINT_OBJ_CXX_STANDARD}
FLAGS "${ADD_ENTRYPOINT_OBJ_FLAGS}"
)
add_library(
${fq_target_name}
# We want an object library as the objects will eventually get packaged into
# an archive (like libc.a).
EXCLUDE_FROM_ALL
OBJECT
${ADD_ENTRYPOINT_OBJ_SRCS}
${ADD_ENTRYPOINT_OBJ_HDRS}
)
target_compile_options(${fq_target_name} BEFORE PRIVATE ${common_compile_options} -DLLVM_LIBC_PUBLIC_PACKAGING)
target_include_directories(${fq_target_name} PRIVATE ${include_dirs})
add_dependencies(${fq_target_name} ${full_deps_list})
set_target_properties(
${fq_target_name}
PROPERTIES
ENTRYPOINT_NAME ${ADD_ENTRYPOINT_OBJ_NAME}
TARGET_TYPE ${ENTRYPOINT_OBJ_TARGET_TYPE}
OBJECT_FILE "$<TARGET_OBJECTS:${fq_target_name}>"
# TODO: We don't need to list internal object files if the internal
# target is a normal static library.
OBJECT_FILE_RAW "$<TARGET_OBJECTS:${internal_target_name}>"
CXX_STANDARD ${ADD_ENTRYPOINT_OBJ_CXX_STANDARD}
DEPS "${fq_deps_list}"
FLAGS "${ADD_ENTRYPOINT_OBJ_FLAGS}"
)
if(LLVM_LIBC_ENABLE_LINTING)
if(NOT LLVM_LIBC_CLANG_TIDY)
message(FATAL_ERROR "Something is wrong! LLVM_LIBC_ENABLE_LINTING is "
"ON but LLVM_LIBC_CLANG_TIDY is not set.")
endif()
# We only want a second invocation of clang-tidy to run
# restrict-system-libc-headers if the compiler-resource-dir was set in
# order to prevent false-positives due to a mismatch between the host
# compiler and the compiled clang-tidy.
if(COMPILER_RESOURCE_DIR)
# We run restrict-system-libc-headers with --system-headers to prevent
# transitive inclusion through compler provided headers.
set(restrict_system_headers_check_invocation
COMMAND ${LLVM_LIBC_CLANG_TIDY} --system-headers
--checks="-*,llvmlibc-restrict-system-libc-headers"
# We explicitly set the resource dir here to match the
# resource dir of the host compiler.
"--extra-arg=-resource-dir=${COMPILER_RESOURCE_DIR}"
--quiet
-p ${PROJECT_BINARY_DIR}
${ADD_ENTRYPOINT_OBJ_SRCS}
)
else()
set(restrict_system_headers_check_invocation
COMMAND ${CMAKE_COMMAND} -E echo "Header file check skipped")
endif()
set(lint_timestamp "${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 ${LLVM_LIBC_CLANG_TIDY}
"--extra-arg=-fno-caret-diagnostics" --quiet
# Path to directory containing compile_commands.json
-p ${PROJECT_BINARY_DIR}
${ADD_ENTRYPOINT_OBJ_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} ${ADD_ENTRYPOINT_OBJ_SRCS}
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
)
endif()
endfunction(create_entrypoint_object)
# Internal function, used by `add_entrypoint_object`.
function(expand_flags_for_entrypoint_object target_name flags)
cmake_parse_arguments(
"EXPAND_FLAGS"
"IGNORE_MARKER" # Optional arguments
"" # Single-value arguments
"DEPENDS;FLAGS" # Multi-value arguments
${ARGN}
)
list(LENGTH flags nflags)
if(NOT ${nflags})
create_entrypoint_object(
${target_name}
DEPENDS ${EXPAND_FLAGS_DEPENDS}
FLAGS ${EXPAND_FLAGS_FLAGS}
${EXPAND_FLAGS_UNPARSED_ARGUMENTS}
)
return()
endif()
list(POP_FRONT flags flag)
extract_flag_modifier(${flag} real_flag modifier)
if(NOT "${modifier}" STREQUAL "NO")
expand_flags_for_entrypoint_object(
${target_name}
"${flags}"
DEPENDS "${EXPAND_FLAGS_DEPENDS}" IGNORE_MARKER
FLAGS "${EXPAND_FLAGS_FLAGS}" IGNORE_MARKER
"${EXPAND_FLAGS_UNPARSED_ARGUMENTS}"
)
endif()
if("${real_flag}" STREQUAL "" OR "${modifier}" STREQUAL "ONLY")
return()
endif()
set(NEW_FLAGS ${EXPAND_FLAGS_FLAGS})
list(REMOVE_ITEM NEW_FLAGS ${flag})
get_fq_dep_list_without_flag(NEW_DEPS ${real_flag} ${EXPAND_FLAGS_DEPENDS})
# Only target with `flag` has `.__NO_flag` target, `flag__NO` and
# `flag__ONLY` do not.
if(NOT "${modifier}")
set(TARGET_NAME "${target_name}.__NO_${flag}")
else()
set(TARGET_NAME "${target_name}")
endif()
expand_flags_for_entrypoint_object(
${TARGET_NAME}
"${flags}"
DEPENDS "${NEW_DEPS}" IGNORE_MARKER
FLAGS "${NEW_FLAGS}" IGNORE_MARKER
"${EXPAND_FLAGS_UNPARSED_ARGUMENTS}"
)
endfunction(expand_flags_for_entrypoint_object)
function(add_entrypoint_object target_name)
cmake_parse_arguments(
"ADD_TO_EXPAND"
"" # Optional arguments
"NAME" # Single value arguments
"DEPENDS;FLAGS" # Multi-value arguments
${ARGN}
)
get_fq_target_name(${target_name} fq_target_name)
if(ADD_TO_EXPAND_DEPENDS AND ("${SHOW_INTERMEDIATE_OBJECTS}" STREQUAL "DEPS"))
message(STATUS "Gathering FLAGS from dependencies for ${fq_target_name}")
endif()
get_fq_deps_list(fq_deps_list ${ADD_TO_EXPAND_DEPENDS})
get_flags_from_dep_list(deps_flag_list ${fq_deps_list})
list(APPEND ADD_TO_EXPAND_FLAGS ${deps_flag_list})
remove_duplicated_flags("${ADD_TO_EXPAND_FLAGS}" flags)
list(SORT flags)
if(SHOW_INTERMEDIATE_OBJECTS AND flags)
message(STATUS "Object library ${fq_target_name} has FLAGS: ${flags}")
endif()
if(NOT ADD_TO_EXPAND_NAME)
set(ADD_TO_EXPAND_NAME ${target_name})
endif()
expand_flags_for_entrypoint_object(
${fq_target_name}
"${flags}"
NAME ${ADD_TO_EXPAND_NAME} IGNORE_MARKER
DEPENDS "${fq_deps_list}" IGNORE_MARKER
FLAGS "${flags}" IGNORE_MARKER
${ADD_TO_EXPAND_UNPARSED_ARGUMENTS}
)
endfunction(add_entrypoint_object)
set(ENTRYPOINT_EXT_TARGET_TYPE "ENTRYPOINT_EXT")
# A rule for external entrypoint targets.
# Usage:
# add_entrypoint_external(
# <target_name>
# DEPENDS <list of dependencies>
# )
function(add_entrypoint_external target_name)
cmake_parse_arguments(
"ADD_ENTRYPOINT_EXT"
"" # No optional arguments
"" # No single value arguments
"DEPENDS" # Multi value arguments
${ARGN}
)
get_fq_target_name(${target_name} fq_target_name)
set(entrypoint_name ${target_name})
add_custom_target(${fq_target_name})
set_target_properties(
${fq_target_name}
PROPERTIES
"ENTRYPOINT_NAME" ${entrypoint_name}
"TARGET_TYPE" ${ENTRYPOINT_EXT_TARGET_TYPE}
"DEPS" "${ADD_ENTRYPOINT_EXT_DEPENDS}"
)
endfunction(add_entrypoint_external)
# Rule build a redirector object file.
function(add_redirector_object target_name)
cmake_parse_arguments(
"REDIRECTOR_OBJECT"
"" # No optional arguments
"SRC" # The cpp file in which the redirector is defined.
"" # No multivalue arguments
${ARGN}
)
if(NOT REDIRECTOR_OBJECT_SRC)
message(FATAL_ERROR "'add_redirector_object' rule requires SRC option listing one source file.")
endif()
add_library(
${target_name}
EXCLUDE_FROM_ALL
OBJECT
${REDIRECTOR_OBJECT_SRC}
)
target_compile_options(
${target_name}
BEFORE PRIVATE -fPIC ${LIBC_COMPILE_OPTIONS_DEFAULT}
)
endfunction(add_redirector_object)