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[cmake] Add support for building the swift stdlib with LTO. #36570

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Merged
merged 1 commit into from
Mar 26, 2021
Merged

[cmake] Add support for building the swift stdlib with LTO. #36570

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4 changes: 4 additions & 0 deletions stdlib/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,10 @@ option(SWIFT_BUILD_TEST_SUPPORT_MODULES
"Whether to build StdlibUnittest and other test support modules. Defaults to On when SWIFT_BUILD_SDK_OVERLAY is On, or when SWIFT_INCLUDE_TESTS is On."
"${SWIFT_BUILD_TEST_SUPPORT_MODULES_default}")

set(SWIFT_STDLIB_ENABLE_LTO OFF CACHE STRING "Build Swift stdlib with LTO. One
must specify the form of LTO by setting this to one of: 'full', 'thin'. This
option only affects the standard library and runtime, not tools.")

#
# End of user-configurable options.
#
Expand Down
13 changes: 8 additions & 5 deletions stdlib/cmake/modules/AddSwiftStdlib.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -623,7 +623,8 @@ function(_add_swift_target_library_single target name)
DARWIN_INSTALL_NAME_DIR
SDK
DEPLOYMENT_VERSION_MACCATALYST
MACCATALYST_BUILD_FLAVOR)
MACCATALYST_BUILD_FLAVOR
ENABLE_LTO)
set(SWIFTLIB_SINGLE_multiple_parameter_options
C_COMPILE_FLAGS
DEPENDS
Expand Down Expand Up @@ -778,6 +779,7 @@ function(_add_swift_target_library_single target name)
${SWIFTLIB_SINGLE_IS_SDK_OVERLAY_keyword}
${embed_bitcode_arg}
${SWIFTLIB_SINGLE_STATIC_keyword}
ENABLE_LTO "${SWIFTLIB_SINGLE_ENABLE_LTO}"
INSTALL_IN_COMPONENT "${SWIFTLIB_SINGLE_INSTALL_IN_COMPONENT}"
MACCATALYST_BUILD_FLAVOR "${SWIFTLIB_SINGLE_MACCATALYST_BUILD_FLAVOR}")
add_swift_source_group("${SWIFTLIB_SINGLE_EXTERNAL_SOURCES}")
Expand Down Expand Up @@ -1139,7 +1141,7 @@ function(_add_swift_target_library_single target name)
endif()

if (NOT SWIFTLIB_SINGLE_TARGET_LIBRARY)
set(lto_type "${SWIFT_TOOLS_ENABLE_LTO}")
set(lto_type "${SWIFT_STDLIB_ENABLE_LTO}")
endif()

_add_target_variant_c_compile_flags(
Expand Down Expand Up @@ -1988,7 +1990,7 @@ function(add_swift_target_library name)
DEPLOYMENT_VERSION_TVOS "${SWIFTLIB_DEPLOYMENT_VERSION_TVOS}"
DEPLOYMENT_VERSION_WATCHOS "${SWIFTLIB_DEPLOYMENT_VERSION_WATCHOS}"
MACCATALYST_BUILD_FLAVOR "${maccatalyst_build_flavor}"

ENABLE_LTO "${SWIFT_STDLIB_ENABLE_LTO}"
GYB_SOURCES ${SWIFTLIB_GYB_SOURCES}
)
if(NOT SWIFT_BUILT_STANDALONE AND NOT "${CMAKE_C_COMPILER_ID}" MATCHES "Clang")
Expand Down Expand Up @@ -2322,15 +2324,15 @@ function(_add_swift_target_executable_single name)
ARCH "${SWIFTEXE_SINGLE_ARCHITECTURE}"
BUILD_TYPE "${CMAKE_BUILD_TYPE}"
ENABLE_ASSERTIONS "${LLVM_ENABLE_ASSERTIONS}"
ENABLE_LTO "${SWIFT_TOOLS_ENABLE_LTO}"
ENABLE_LTO "${SWIFT_STDLIB_ENABLE_LTO}"
ANALYZE_CODE_COVERAGE "${SWIFT_ANALYZE_CODE_COVERAGE}"
RESULT_VAR_NAME c_compile_flags)
_add_target_variant_link_flags(
SDK "${SWIFTEXE_SINGLE_SDK}"
ARCH "${SWIFTEXE_SINGLE_ARCHITECTURE}"
BUILD_TYPE "${CMAKE_BUILD_TYPE}"
ENABLE_ASSERTIONS "${LLVM_ENABLE_ASSERTIONS}"
ENABLE_LTO "${SWIFT_TOOLS_ENABLE_LTO}"
ENABLE_LTO "${SWIFT_STDLIB_ENABLE_LTO}"
LTO_OBJECT_NAME "${name}-${SWIFTEXE_SINGLE_SDK}-${SWIFTEXE_SINGLE_ARCHITECTURE}"
ANALYZE_CODE_COVERAGE "${SWIFT_ANALYZE_CODE_COVERAGE}"
RESULT_VAR_NAME link_flags
Expand All @@ -2350,6 +2352,7 @@ function(_add_swift_target_executable_single name)
SDK ${SWIFTEXE_SINGLE_SDK}
ARCHITECTURE ${SWIFTEXE_SINGLE_ARCHITECTURE}
COMPILE_FLAGS ${SWIFTEXE_SINGLE_COMPILE_FLAGS}
ENABLE_LTO "${SWIFT_STDLIB_ENABLE_LTO}"
IS_MAIN)
add_swift_source_group("${SWIFTEXE_SINGLE_EXTERNAL_SOURCES}")

Expand Down
18 changes: 16 additions & 2 deletions stdlib/cmake/modules/SwiftSource.cmake
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Original file line number Diff line number Diff line change
@@ -1,6 +1,15 @@
include(macCatalystUtils)
include(SwiftUtils)

function(_compute_lto_swift_flag option out_var)
string(TOLOWER "${option}" lowercase_option)
if (lowercase_option STREQUAL "full")
set(${out_var} "-lto=llvm-full" PARENT_SCOPE)
elseif (lowercase_option STREQUAL "thin")
set(${out_var} "-lto=llvm-thin" PARENT_SCOPE)
endif()
endfunction()

# Compute the library subdirectory to use for the given sdk and
# architecture, placing the result in 'result_var_name'.
function(compute_library_subdir result_var_name sdk arch)
Expand Down Expand Up @@ -42,7 +51,7 @@ function(handle_swift_sources
cmake_parse_arguments(SWIFTSOURCES
"IS_MAIN;IS_STDLIB;IS_STDLIB_CORE;IS_SDK_OVERLAY;EMBED_BITCODE;STATIC"
"SDK;ARCHITECTURE;INSTALL_IN_COMPONENT;MACCATALYST_BUILD_FLAVOR"
"DEPENDS;COMPILE_FLAGS;MODULE_NAME"
"DEPENDS;COMPILE_FLAGS;MODULE_NAME;ENABLE_LTO"
${ARGN})
translate_flag(${SWIFTSOURCES_IS_MAIN} "IS_MAIN" IS_MAIN_arg)
translate_flag(${SWIFTSOURCES_IS_STDLIB} "IS_STDLIB" IS_STDLIB_arg)
Expand Down Expand Up @@ -107,7 +116,12 @@ function(handle_swift_sources
if(sdk IN_LIST SWIFT_APPLE_PLATFORMS OR sdk STREQUAL "MACCATALYST")
list(APPEND swift_compile_flags "-save-optimization-record=bitstream")
endif()

if (SWIFTSOURCES_ENABLE_LTO)
_compute_lto_swift_flag("${SWIFTSOURCES_ENABLE_LTO}" _lto_flag_out)
if (_lto_flag_out)
list(APPEND swift_compile_flags "${_lto_flag_out}")
endif()
endif()
_compile_swift_files(
dependency_target
module_dependency_target
Expand Down