blob: bdaa08d07bc21bb3b33e88075325c34886ea68e2 [file] [log] [blame]
# Copyright 2019 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import("$zx/public/gn/config/standard.gni")
import("$zx/public/gn/toolchain/clang.gni")
import("levels.gni")
declare_args() {
# Clang crash reports directory path. Use empty path to disable altogether.
crash_diagnostics_dir = "$root_build_dir/clang-crashreports"
# The `--sysroot` directory for host compilations.
# This can be a string, which only applies to $host_os-$host_cpu.
# Or it can be a list of scopes containing `cpu`, `os`, and `sysroot`.
# The empty list (or empty string) means don't use `--sysroot` at all.
sysroot = standard_sysroot
}
# Convert a string to a list.
if (sysroot == "") {
sysroot = []
} else if (sysroot == "$sysroot") {
sysroot = [
{
cpu = host_cpu
os = host_os
sysroot = sysroot
},
]
}
config("sysroot") {
foreach(host, sysroot) {
if (host.cpu == current_cpu && host.os == current_os) {
compiler_flags =
[ "--sysroot=" + rebase_path(host.sysroot, root_build_dir) ]
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags
}
}
}
if (current_os == "mac") {
# Only the native host linker works for macOS.
linker = ""
} else if (is_gcc) {
# Assume ld.gold is available for any native Linux host, and for any ELF
# cross-compile target. Use Gold for userland, and BFD ld for kernel.
if (current_os == "linux" ||
((current_cpu != host_cpu || current_os != host_os) && !is_kernel &&
current_os != "win")) {
linker = "gold"
} else {
# For GCC on non-ELF hosts, use the system default linker.
linker = ""
}
} else {
# Always use lld with Clang.
linker = "lld"
}
config("compiler") {
compiler_flags = []
defines = []
ldflags = []
# For GCC, the compiler command implies the target.
# For Clang, there's a single compiler command that takes `--target`.
if (!is_gcc && (current_cpu != host_cpu || current_os != host_os)) {
compiler_flags += [ "--target=${toolchain.target_tuple}" ]
}
if (linker != "") {
ldflags += [ "-fuse-ld=$linker" ]
}
if (defined(toolchain.version_string) && toolchain.version_string != "") {
# Nothing uses this define, but its presence on compilation command
# lines ensures that Ninja will rebuild things when a new compiler
# version arrives.
defines += [ "TOOLCHAIN_VERSION=${toolchain.version_string}" ]
}
# This is the default already on Fuchsia and maybe others, but never hurts.
cflags = [ "-fno-common" ]
configs = [
":color_diagnostics",
# TODO: "$current_os:compiler",
]
if (is_host) {
configs += [ ":sysroot" ]
if (current_os != "win" && current_os != "mac") {
ldflags += [ "-Wl,--build-id" ]
}
} else if (is_fuchsia) {
# TODO(mcgrathr): These should all be default in the compiler driver.
ldflags += [
"-Wl,-z,combreloc",
"-Wl,-z,relro",
"-Wl,-z,now",
"-Wl,-z,text",
]
if (is_gcc) {
# This is predefined by Clang --target=*-fuchsia.
# But the GCC toolchain is the generic --target=*-elf one.
defines += [ "__Fuchsia__" ]
# These are done by default in the Clang toolchain.
cflags += [ "-fasynchronous-unwind-tables" ]
ldflags += [
"-Wl,--build-id",
"-Wl,--eh-frame-hdr",
"-Wl,--hash-style=gnu",
]
# In the Clang toolchain assembly files with no explicit marker don't
# cause the presumption of executable stack as they do in GCC.
ldflags += [ "-Wl,-z,noexecstack" ]
} else {
# TODO(mcgrathr): This should be default in the compiler driver.
ldflags += [ "-Wl,--pack-dyn-relocs=relr" ]
}
if (current_cpu == "arm64") {
# Generate code for the fairly generic cortex-a53.
compiler_flags += [ "-mcpu=cortex-a53", "-march=armv8.1-a" ]
# x18 is reserved in the Fuchsia userland ABI so it can be used
# for things like -fsanitize=shadow-call-stack. In the kernel,
# it's reserved so we can use it to point at the per-CPU structure.
compiler_flags += [ "-ffixed-x18" ]
}
}
if (is_host) {
configs += [ ":static-libc++" ]
# For host tools without C++, ignore the unused arguments.
if (!is_gcc) {
ldflags += [ "-Wno-unused-command-line-argument" ]
}
}
if (!is_gcc && crash_diagnostics_dir != "") {
compiler_flags += [ "-fcrash-diagnostics-dir=" +
rebase_path(crash_diagnostics_dir, root_build_dir) ]
}
include_dirs = toolchain.include_dirs
lib_dirs = toolchain.lib_dirs
asmflags = compiler_flags
cflags += compiler_flags
ldflags += compiler_flags
}
config("language") {
cflags_c = [ "-std=c11" ]
cflags_cc = [ "-std=c++17" ]
if (current_os == "mac") {
# macOS needs this to not complain about C++17isms that older macOS
# system libc++ doesn't support. But we use our own toolchain's static
# libc++ anyway.
cflags_cc += [ "-faligned-allocation" ]
# libc++ headers mark some symbols as unavailable on macOS by default
# because the system libc++ doesn't support them. But we use our own
# toolchain's static libc++ anyway.
defines = [ "_LIBCPP_DISABLE_AVAILABILITY" ]
}
}
config("color_diagnostics") {
# GCC correctly defaults this from the terminal, so leave it alone.
if (!is_gcc) {
compiler_flags = [ "-fcolor-diagnostics" ]
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags
# The macOS linker does not support `--color-diagnostics`.
if (current_os != "mac") {
ldflags += [ "-Wl,--color-diagnostics" ]
}
}
}
config("relative_paths") {
# Make builds independent of absolute file path. The file names embedded
# in debugging information will be expressed as relative to the build
# directory, e.g. "../.." for an "out/subdir" under //. This is
# consistent with the file names in __FILE__ expansions (e.g. in
# assertion messages), which the compiler doesn't provide a way to remap.
# That way source file names in logging and symbolization can all be
# treated the same way. This won't go well if $root_build_dir is not a
# subdirectory of //, but there isn't a better option to keep all source
# file name references uniformly relative to a single root.
absolute_path = rebase_path("//.")
relative_path = rebase_path("//.", root_build_dir)
# This makes sure that the DW_AT_comp_dir string (the current
# directory while running the compiler, which is the basis for all
# relative source file names in the DWARF info) is represented as
# relative to //.
compiler_flags = [ "-fdebug-prefix-map=$absolute_path=$relative_path" ]
if (!is_gcc) {
# This makes sure that include directories in the toolchain are
# represented as relative to the build directory (because that's how we
# invoke the compiler), rather than absolute. This can affect __FILE__
# expansions (e.g. assertions in system headers). We normally run a
# compiler that's someplace within the source tree, so its absolute
# installation path will have a prefix matching `absolute_path` and
# hence be mapped to `relative_path` in the debugging information, so
# this should actually be superfluous for purposes of the debugging
# information.
compiler_flags += [ "-no-canonical-prefixes" ]
}
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags
}
config("nolibc") {
ldflags = [ "-nostartfiles" ]
# Don't use -nostdlib, because the builtins (or libgcc) are what we want
# and are otherwise annoying to find and specify. It's just the -lc that
# we really want to defeat, and that's handled by giving a -L that will
# find exactly nothing but a dummy libc.so. Clang has -nolibc to kill
# the -lc, but for C++ it still uses -lm under -nolibc. So this is still
# needed to make -lm into a dummy, though for -lc only GCC needs it.
lib_dirs = [ "libc-dummy" ]
if (is_gcc) {
# Include this in every link.
# Note GN requires "./" so it doesn't think this should mean a -l switch.
libs = [ "./dso_handle.ld" ]
} else {
# TODO(mcgrathr): GCC 9 has -nolibc, so use it when we get that toolchain.
ldflags += [ "-nolibc" ]
}
}
config("freestanding") {
cflags = [ "-ffreestanding" ]
# In Clang -fasynchronous-unwind-tables is the default for *-fuchsia
# targets. But -ffreestanding defeats that (in target-independent logic
# in the Clang driver). So add it back explicitly. For GCC, it's
# already added explicitly in :compiler regardless so don't double it.
if (!is_gcc) {
cflags += [ "-fasynchronous-unwind-tables" ]
}
ldflags = cflags
}
config("data_sections") {
cflags = [ "-fdata-sections" ]
}
config("linker_gc") {
configs = [ ":data_sections" ]
cflags = [ "-ffunction-sections" ]
ldflags = cflags
if (current_os == "mac") {
ldflags += [ "-Wl,-dead_strip" ]
} else if (current_os == "win") {
ldflags += [ "-Wl,/opt:ref" ]
} else {
ldflags += [ "-Wl,--gc-sections" ]
}
}
config("assert_level") {
assert(assert_level >= 0)
defines = [ "ZX_DEBUGLEVEL=$assert_level" ]
if (is_kernel) {
defines += [ "LK_DEBUGLEVEL=$assert_level" ]
}
if (assert_level == 0) {
defines += [ "NDEBUG" ]
}
}
config("opt_level") {
if (opt_level == -1) {
compiler_flags = [ "-O0" ]
} else {
assert(opt_level >= 0)
# TODO(TC-472): opt_level==0 should mean -Og if that ever comes
# to mean something useful. Correctly clang -Og is just -O1, which
# is still not as debugging-friendly as -O0, so don't use it. It
# also doesn't actually work at all when LTO is enabled (the linker
# plugin doesn't grok -Og, but the compiler driver passes it -Og).
if (opt_level == 4) {
if (is_gcc) {
compiler_flags = [ "-Os" ]
} else {
compiler_flags = [ "-Oz" ]
}
} else {
compiler_flags = [ "-O$opt_level" ]
}
}
configs = []
if (opt_level > 1 && is_kernel) {
# Our code should never rely on C's unique function pointer semantics,
# which is broken by --icf=all for sometimes substantial space savings.
configs += [ ":icf" ]
}
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags
if (opt_level > 2) {
# Enable optimal string merging.
ldflags += [ "-Wl,-O2" ]
}
}
# This is separate from opt_level so it can be removed.
config("default_linker_gc") {
# TODO(mcgrathr): Kernel can't be built without --gc-sections.
# The macOS host linker seems to have some bugs with its
# equivalent, so don't use it there.
if ((opt_level > 0 || toolchain.environment == "kernel") &&
current_os != "mac") {
configs = [ ":linker_gc" ]
}
}
config("symbol_level") {
assert(symbol_level >= 0 && symbol_level <= 2)
if (symbol_level == 0) {
compiler_flags = [ "-g0" ]
} else if (symbol_level == 1) {
compiler_flags = [ "-gline-tables-only" ]
} else if (symbol_level == 2) {
compiler_flags = [ "-g3" ]
}
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags
if (symbol_level > 0 && current_os == "win") {
# TODOD: ??? This produces the .pdb file, but it doesn't seem
# to get the DWARF data out of the main output file.
ldflags += [ "-Wl,/debug:full" ]
}
}
config("werror") {
cflags = [
"-Werror",
# Declarations marked as deprecated should not cause build failures.
# Rather they should emit warnings to notify developers about the use
# of deprecated interfaces.
"-Wno-error=deprecated-declarations",
# Do not add additional `-Wno-error=...` switches to this config!
]
if (current_os == "win") {
ldflags = [ "-Wl,/WX" ]
}
}
config("default_warnings") {
cflags = [
"-Wall",
"-Wextra",
"-Wno-multichar",
"-Wno-unused-parameter",
"-Wno-unused-function",
"-Werror=unused-label",
"-Werror=return-type",
"-Wno-address-of-packed-member",
]
cflags_c = [
"-Werror=implicit-function-declaration",
"-Wstrict-prototypes",
"-Wwrite-strings",
"-Wno-absolute-value",
]
cflags_cc = [
"-Wconversion",
"-Wno-sign-conversion",
"-Wextra-semi",
]
if (is_gcc) {
cflags += [
"-Wno-nonnull-compare",
"-Wno-format-truncation",
]
} else {
cflags += [
"-Wnewline-eof",
"-Wimplicit-fallthrough",
]
}
}
config("default_template_backtrace_limit") {
cflags_cc = [ "-ftemplate-backtrace-limit=0" ]
}
config("icf") {
# This changes C/C++ semantics and might be incompatible with third-party
# code that relies on function pointers comparison.
if (current_os == "win" && (linker == "lld" || !is_gcc)) {
ldflags = [ "-Wl,/opt:icf=all" ]
} else if (linker == "gold" || linker == "lld") {
ldflags = [ "-Wl,--icf=all" ]
}
}
config("exceptions") {
cflags_cc = [ "-fexceptions" ]
cflags_objcc = cflags_cc
ldflags = cflags_cc
}
config("no_exceptions") {
cflags_cc = [ "-fno-exceptions" ]
cflags_objcc = cflags_cc
ldflags = cflags_cc
}
config("rtti") {
cflags_cc = [ "-frtti" ]
cflags_objcc = cflags_cc
ldflags = cflags_cc
}
config("no_rtti") {
cflags_cc = [ "-fno-rtti" ]
cflags_objcc = cflags_cc
ldflags = cflags_cc
}
config("no_threadsafe_statics") {
cflags_cc = [ "-fno-threadsafe-statics" ]
cflags_objcc = cflags_cc
}
config("default_include_dirs") {
include_dirs = [ "$zx/system/public" ]
}
config("default_frame_pointers") {
if (assert_level > 0) {
configs = [ ":frame_pointers" ]
} else {
configs = [ ":no_frame_pointers" ]
}
}
config("frame_pointers") {
defines = [ "WITH_FRAME_POINTERS=1" ]
cflags = [ "-fno-omit-frame-pointer" ]
}
config("no_frame_pointers") {
defines = [ "WITH_FRAME_POINTERS=0" ]
cflags = [ "-fomit-frame-pointer" ]
}
config("thread_safety_annotations") {
if (!is_gcc) {
cflags = [ "-Wthread-safety" ]
defines = [ "_LIBCPP_ENABLE_THREAD_SAFETY_ANNOTATIONS=1" ]
}
}
config("no_stack_protector") {
cflags = [ "-fno-stack-protector" ]
}
config("no_safestack") {
if (!is_gcc) {
cflags = [ "-fno-sanitize=safe-stack" ]
}
configs = [ ":no_stack_protector" ]
}
config("no_sanitizers") {
cflags = [ "-fno-sanitize=all" ]
if (!is_gcc) {
cflags += [ "-fsanitize-coverage=0" ]
}
configs = [ ":no_stack_protector" ]
}
# TODO(TC-539) Remove this once the warning with fit::variant/fit::optional is addressed.
config("no_maybe_uninitialized") {
if (is_gcc) {
cflags = [ "-Wno-maybe-uninitialized" ]
}
}
# Compile code appropriately to be linked into a shared library.
config("shared_library_config") {
if (current_os != "mac") {
# Assembly code can use `#ifdef __PIC__`.
compiler_flags = [ "-fPIC" ]
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags
}
}
# Don't allow dangling undefined references in shared libraries.
# All references should be satisfied by link-time library dependencies.
config("no_undefined_symbols") {
if (current_os == "mac") {
ldflags = [ "-Wl,-undefined,error" ]
} else {
ldflags = [ "-Wl,-z,defs" ]
}
}
config("visibility_hidden") {
cflags = [ "-fvisibility=hidden" ]
cflags_cc = [ "-fvisibility-inlines-hidden" ]
}
config("machine") {
ldflags = []
if (current_cpu == "arm64" && current_os != "win") {
# The linker rewrites instructions to work around a CPU bug.
ldflags += [ "-Wl,--fix-cortex-a53-843419" ]
}
if (is_fuchsia) {
# TODO(ZX-2300): Really need to get this nailed down once and for all
# and set by default in the compiler driver (Clang at least).
ldflags += [ "-Wl,-z,max-page-size=4096" ]
}
}
config("user") {
defines = [ "_ALL_SOURCE" ]
configs = [
":nolibc",
"$zx/third_party/ulib/musl:headers",
]
}
config("user_executable") {
# Fuchsia userland code is compiled as PIE by default.
# In Clang, this is the default in the compiler driver for *-fuchsia targets.
# For GCC, it must be explicit.
if (is_gcc) {
compiler_flags = [ "-fPIE" ]
asmflags = compiler_flags
cflags = compiler_flags
ldflags = compiler_flags + [ "-Wl,-pie" ]
} else {
ldflags = []
}
# Specify the dynamic linker if building a variant that uses a separate
# set of libraries. With GCC, the dynamic linker must be explicit even
# in the default case because the compiler driver is not inherently
# configured for Fuchsia as it is in Clang.
if (is_gcc || toolchain.libprefix != "") {
ldflags += [ "-Wl,-dynamic-linker,${toolchain.libprefix}ld.so.1" ]
}
}
config("integer-paranoia") {
cflags = [
"-fsanitize=integer-divide-by-zero,signed-integer-overflow",
"-fsanitize-undefined-trap-on-error",
]
}
config("static-libc++") {
if (current_os == "mac") {
# The macOS driver doesn't support -static-libstdc++ properly, so pass
# the libraries directly. This has to locate the files explicitly in
# the toolchain, because -lc++ would look for the shared library.
ldflags = [
"-nostdlib++",
rebase_path("${toolchain.tool_dir}/../lib/libc++.a", root_build_dir),
]
} else {
ldflags = [ "-static-libstdc++" ]
# TODO(TC-74): The implicitly linked static libc++.a depends on these.
if (current_os == "linux") {
libs = [
"dl",
"pthread",
]
}
}
}
if (is_fuchsia) {
toolchain_runtime_deps("static-libc++-deps") {
cflags = toolchain.runtime_deps_cflags
ldflags = [ "-static-libstdc++" ]
}
toolchain_runtime_deps("shared-libc++-deps") {
cflags = toolchain.runtime_deps_cflags
ldflags = []
}
}
config("rodso") {
if (is_gcc) {
inputs = [
"rodso.ld",
]
ldflags = [ "-Wl,-T," + rebase_path(inputs[0], root_build_dir) ]
}
}