| //! Runs `rustc --print cfg` to get built-in cfg flags. |
| |
| use std::process::Command; |
| |
| use anyhow::Result; |
| use rustc_hash::FxHashMap; |
| |
| use crate::{cfg_flag::CfgFlag, utf8_stdout, ManifestPath}; |
| |
| pub(crate) fn get( |
| cargo_toml: Option<&ManifestPath>, |
| target: Option<&str>, |
| extra_env: &FxHashMap<String, String>, |
| ) -> Vec<CfgFlag> { |
| let _p = profile::span("rustc_cfg::get"); |
| let mut res = Vec::with_capacity(6 * 2 + 1); |
| |
| // Some nightly-only cfgs, which are required for stdlib |
| res.push(CfgFlag::Atom("target_thread_local".into())); |
| for ty in ["8", "16", "32", "64", "cas", "ptr"] { |
| for key in ["target_has_atomic", "target_has_atomic_load_store"] { |
| res.push(CfgFlag::KeyValue { key: key.to_string(), value: ty.into() }); |
| } |
| } |
| |
| match get_rust_cfgs(cargo_toml, target, extra_env) { |
| Ok(rustc_cfgs) => { |
| tracing::debug!( |
| "rustc cfgs found: {:?}", |
| rustc_cfgs |
| .lines() |
| .map(|it| it.parse::<CfgFlag>().map(|it| it.to_string())) |
| .collect::<Vec<_>>() |
| ); |
| res.extend(rustc_cfgs.lines().filter_map(|it| it.parse().ok())); |
| } |
| Err(e) => tracing::error!("failed to get rustc cfgs: {e:?}"), |
| } |
| |
| res |
| } |
| |
| fn get_rust_cfgs( |
| cargo_toml: Option<&ManifestPath>, |
| target: Option<&str>, |
| extra_env: &FxHashMap<String, String>, |
| ) -> Result<String> { |
| if let Some(cargo_toml) = cargo_toml { |
| let mut cargo_config = Command::new(toolchain::cargo()); |
| cargo_config.envs(extra_env); |
| cargo_config |
| .current_dir(cargo_toml.parent()) |
| .args(&["-Z", "unstable-options", "rustc", "--print", "cfg"]) |
| .env("RUSTC_BOOTSTRAP", "1"); |
| if let Some(target) = target { |
| cargo_config.args(&["--target", target]); |
| } |
| match utf8_stdout(cargo_config) { |
| Ok(it) => return Ok(it), |
| Err(e) => tracing::debug!("{e:?}: falling back to querying rustc for cfgs"), |
| } |
| } |
| // using unstable cargo features failed, fall back to using plain rustc |
| let mut cmd = Command::new(toolchain::rustc()); |
| cmd.envs(extra_env); |
| cmd.args(&["--print", "cfg", "-O"]); |
| if let Some(target) = target { |
| cmd.args(&["--target", target]); |
| } |
| utf8_stdout(cmd) |
| } |