deno/build_extra/rust/rust.gni
2018-12-13 16:16:58 -05:00

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declare_args() {
# Absolute path of rust build files.
rust_build = "//build_extra/rust/"
# Wrapper executable for rustc invocations. This can be used for a caching
# utility, e.g. sccache.
rustc_wrapper = ""
# treat the warnings in rust files as errors
rust_treat_warnings_as_errors = true
}
if (is_win) {
executable_suffix = ".exe"
} else {
executable_suffix = ""
}
# To simplify transitive dependency management with gn, we build all rust
# crates into the same directory. We need to be careful not to have crates
# with the same name.
out_dir = "$root_out_dir/rust_crates"
# The official way of building Rust executables is to to let rustc do the
# linking. However, we'd prefer to leave it in the hands of gn/ninja:
# * It allows us to use source sets.
# * It allows us to use the bundled lld that Chromium and V8 use.
# * We have more control over build flags.
# * To sidestep rustc weirdness (e.g. on Windows, it always links with the
# release C runtime library, even for debug builds).
#
# The `get_rustc_info` tool outputs the linker flags that are needed to
# successfully link rustc object code into an executable.
# We generate two sets of ldflags:
# `ldflags_bin` : Used for rust_executable targets.
# `ldflags_test`: Used for rust_test targets; includes the test harness.
#
# The tool works by compiling and linking something with rustc, and analyzing
# the arguments it passes to the system linker. That's what dummy.rs is for.
_rustc_info = exec_script("get_rustc_info.py", [], "json")
template("rust_crate") {
config_name = "${target_name}_config"
action_name = "${target_name}_rustc"
forward_variables_from(invoker,
[
"crate_name",
"crate_type",
"crate_version",
"deps",
"inputs",
"features",
"is_test",
"libs",
"source_root",
"testonly",
"treat_warnings_as_errors",
])
if (!defined(crate_name)) {
crate_name = target_name
}
if (!defined(crate_type)) {
crate_type = "rlib"
}
if (!defined(deps)) {
deps = []
}
if (!defined(is_test)) {
is_test = false
}
if (!defined(libs)) {
libs = []
}
if (!defined(treat_warnings_as_errors)) {
# Use global setting if not explicitly specified for this target.
treat_warnings_as_errors = rust_treat_warnings_as_errors
}
if (defined(crate_version)) {
# In our build setup, all crates are built in the same directory. To avoid
# file name conflicts between when multiple versions of the same crate are
# built, add a unique suffix to output file names.
# Unfortunately the version number as such can't be used directly:
# everything after the first dot (.) is thrown away by rust, so in case of
# foo-0.2 vs foo-0.3 only the first '0' would be used, and conflicts would
# still occur. Therefore we use a hash of the version number instead.
crate_suffix = exec_script("//tools/sha256sum.py",
[
"--input=$crate_version",
"--format=-%.8s",
],
"trim string")
} else {
# Of most crates we use only one version; no need for all this difficulty.
crate_suffix = ""
}
# Derive filenames for 'extern' and 'extern_version' linked rust libraries.
extern_rlibs = []
if (defined(invoker.extern)) {
foreach(label, invoker.extern) {
extern_rlibs += [
{
label = label
crate_name = get_label_info(label, "name")
rlib = "$out_dir/lib$crate_name.rlib"
},
]
}
}
if (defined(invoker.extern_version)) {
foreach(info, invoker.extern_version) {
extern_rlibs += [
{
crate_name = info.crate_name
crate_version = info.crate_version
crate_suffix = exec_script("//tools/sha256sum.py",
[
"--input=$crate_version",
"--format=-%.8s",
],
"trim string")
label = ":$crate_name-$crate_version"
rlib = "$out_dir/lib$crate_name$crate_suffix.rlib"
},
]
}
}
config(config_name) {
foreach(extern, extern_rlibs) {
libs += [ extern.rlib ]
}
lib_dirs = [ out_dir ]
}
if (crate_type == "bin") {
rustc_output = "$out_dir/$crate_name$crate_suffix.o"
emit_type = "obj"
} else if (crate_type == "rlib") {
rustc_output = "$out_dir/lib$crate_name$crate_suffix.rlib"
emit_type = "link"
}
source_set(target_name) {
public_deps = [
":$action_name",
]
libs += [ rustc_output ]
all_dependent_configs = [ ":$config_name" ]
}
action(action_name) {
script = "//build_extra/rust/run.py"
sources = [
source_root,
]
outputs = [
rustc_output,
]
depfile = "$out_dir/$crate_name$crate_suffix.d"
if (rustc_wrapper != "") {
args = [ rustc_wrapper ]
} else {
args = []
}
args += [
"rustc",
rebase_path(source_root, root_build_dir),
"--crate-name=$crate_name",
"--crate-type=$crate_type",
"--emit=$emit_type,dep-info",
"--out-dir=" + rebase_path(out_dir, root_build_dir),
# This is to disambiguate multiple versions of the same crate.
"-Cextra-filename=$crate_suffix",
# Appending the rustc version to the crate metadata ensures that they are
# rebuilt when rustc is upgraded, by changing the command line.
"-Cmetadata=\"${crate_suffix}_${_rustc_info.version}\"",
# This is needed for transitive dependencies.
"-L",
"dependency=" + rebase_path(out_dir, root_build_dir),
# Use colorful output even if stdout is redirected and not a tty.
"--color=always",
]
if (defined(crate_version)) {
args += [
# This is used to set env variables for Cargo build compatibility
"--cargo-pkg-version=$crate_version",
]
}
if (is_debug) {
args += [ "-g" ]
}
if (is_official_build) {
args += [ "-O" ]
}
if (is_test) {
args += [ "--test" ]
}
if (treat_warnings_as_errors) {
args += [ "-Dwarnings" ]
}
if (defined(invoker.args)) {
args += invoker.args
}
if (defined(features)) {
foreach(f, features) {
args += [
"--cfg",
"feature=\"" + f + "\"",
]
}
}
# Build the list of '--extern' arguments from the 'extern_rlibs' array.
foreach(extern, extern_rlibs) {
args += [
"--extern",
extern.crate_name + "=" + rebase_path(extern.rlib, root_build_dir),
]
sources += [ extern.rlib ]
deps += [ extern.label ]
}
}
}
template("rust_executable") {
bin_name = target_name + "_bin"
bin_label = ":" + bin_name
rust_crate(bin_name) {
crate_type = "bin"
forward_variables_from(invoker, "*")
}
executable(target_name) {
forward_variables_from(invoker, "*")
if (defined(is_test) && is_test) {
ldflags = _rustc_info.ldflags_test
} else {
ldflags = _rustc_info.ldflags_bin
}
if (!defined(deps)) {
deps = []
}
deps += [ bin_label ]
if (defined(extern)) {
deps += extern
}
if (defined(extern_version)) {
foreach(info, extern_version) {
deps += [ info.label ]
}
}
}
}
template("rust_test") {
rust_executable(target_name) {
forward_variables_from(invoker, "*")
is_test = true
testonly = true
}
}