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[Instructions -0.10% vs main; paired PGO estimate] Seed built-in check-cfg values from an exact static table #134

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[Instructions -0.10% vs main; paired PGO estimate] Seed built-in check-cfg values from an exact static table #134

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239 changes: 221 additions & 18 deletions compiler/rustc_session/src/config/cfg.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -21,7 +21,6 @@
//! - Add the feature gating in `compiler/rustc_feature/src/builtin_attrs.rs`

use std::hash::Hash;
use std::iter;

use rustc_abi::Align;
use rustc_ast::ast;
Expand Down Expand Up @@ -444,24 +443,28 @@ impl CheckCfg {
}

if self.exhaustive_values {
// Get all values map at once otherwise it would be costly.
// (8 values * 220 targets ~= 1760 times, at the time of writing this comment).
let mut values = self
.expecteds
.get_disjoint_mut(VALUES)
.map(|value| value.expect("unable to get all the check-cfg values buckets"));
for (values, known) in values.iter_mut().zip(BUILTIN_TARGET_CFG_VALUES) {
values.extend(known.iter().map(|value| Symbol::intern(value)));
}
let [
Some(values_target_abi),
Some(values_target_arch),
Some(values_target_endian),
Some(values_target_env),
Some(values_target_family),
Some(values_target_object_format),
Some(values_target_os),
Some(values_target_pointer_width),
Some(values_target_vendor),
] = self.expecteds.get_disjoint_mut(VALUES)
else {
panic!("unable to get all the check-cfg values buckets");
};

for target in Target::builtins().chain(iter::once(current_target.clone())) {
values_target_abi,
values_target_arch,
values_target_endian,
values_target_env,
values_target_family,
values_target_object_format,
values_target_os,
values_target_pointer_width,
values_target_vendor,
] = values;

// Custom targets may contribute additional values.
{
let target = current_target;
values_target_abi.insert(target.options.cfg_abi.desc_symbol());
values_target_arch.insert(target.arch.desc_symbol());
values_target_endian.insert(target.options.endian.desc_symbol());
Expand Down Expand Up @@ -500,3 +503,203 @@ impl CheckCfg {
ins!(sym::windows, no_values);
}
}

// The distinct values used by built-in targets, in the same order as VALUES above.
// Avoid constructing every full target specification on each check-cfg invocation.
// `builtin_target_cfg_values_match_targets` checks exact equality, including unused
// enum variants and changes to the set of targets, so diagnostics stay unchanged.
const BUILTIN_TARGET_CFG_VALUES: [&[&str]; 9] = [
&[
"",
"abi64",
"abiv2",
"abiv2hf",
"eabi",
"eabihf",
"elfv1",
"elfv2",
"fortanix",
"ilp32",
"ilp32e",
"llvm",
"macabi",
"pauthtest",
"sim",
"softfloat",
"spe",
"uwp",
"v8plus",
"vec-extabi",
"x32",
], // abi
&[
"aarch64",
"amdgpu",
"arm",
"arm64ec",
"avr",
"bpf",
"csky",
"hexagon",
"loongarch32",
"loongarch64",
"m68k",
"mips",
"mips32r6",
"mips64",
"mips64r6",
"msp430",
"nvptx64",
"powerpc",
"powerpc64",
"riscv32",
"riscv64",
"s390x",
"sparc",
"sparc64",
"wasm32",
"wasm64",
"x86",
"x86_64",
"xtensa",
], // arch
&["big", "little"], // target-endian
&[
"",
"gnu",
"macabi",
"mlibc",
"msvc",
"musl",
"newlib",
"nto70",
"nto71",
"nto71_iosock",
"ohos",
"p1",
"p2",
"p3",
"relibc",
"sgx",
"sim",
"uclibc",
"v5",
], // env
&["unix", "wasm", "windows"], // target-family
&["coff", "elf", "mach-o", "wasm", "xcoff"], // binary-format
&[
"aix",
"amdhsa",
"android",
"cuda",
"cygwin",
"dragonfly",
"emscripten",
"espidf",
"freebsd",
"fuchsia",
"haiku",
"helenos",
"hermit",
"horizon",
"hurd",
"illumos",
"ios",
"l4re",
"linux",
"lynxos178",
"macos",
"managarm",
"motor",
"netbsd",
"none",
"nto",
"nuttx",
"openbsd",
"ps3",
"psp",
"psx",
"qnx",
"qurt",
"redox",
"rtems",
"solaris",
"solid_asp3",
"teeos",
"trusty",
"tvos",
"uefi",
"unknown",
"vexos",
"visionos",
"vita",
"vxworks",
"wasi",
"watchos",
"windows",
"xous",
"zkvm",
], // os
&["16", "32", "64"], // target-pointer-width
&[
"amd",
"apple",
"espressif",
"fortanix",
"ibm",
"kmc",
"mti",
"nintendo",
"nvidia",
"openwrt",
"pc",
"risc0",
"sony",
"sun",
"unikraft",
"unknown",
"uwp",
"vex",
"win7",
"wrs",
], // vendor
];

#[cfg(test)]
mod tests {
use std::collections::BTreeSet;

use super::*;

#[test]
fn builtin_target_cfg_values_match_targets() {
rustc_span::create_default_session_globals_then(|| {
let mut actual: [BTreeSet<String>; 9] = std::array::from_fn(|_| BTreeSet::new());
for target in Target::builtins() {
let values = [
vec![target.options.cfg_abi.desc_symbol().to_string()],
vec![target.arch.desc_symbol().to_string()],
vec![target.options.endian.desc_symbol().to_string()],
vec![target.options.env.desc_symbol().to_string()],
target.options.families.iter().map(|family| family.to_string()).collect(),
vec![target.options.binary_format.desc_symbol().to_string()],
vec![target.options.os.desc_symbol().to_string()],
vec![target.pointer_width.to_string()],
vec![target.vendor_symbol().to_string()],
];
for (actual, values) in actual.iter_mut().zip(values) {
actual.extend(values);
}
}
for (index, (actual, expected)) in
actual.iter().zip(BUILTIN_TARGET_CFG_VALUES).enumerate()
{
assert_eq!(
actual.iter().map(String::as_str).collect::<Vec<_>>(),
expected,
"update BUILTIN_TARGET_CFG_VALUES entry {index} to match the built-in targets"
);
}
});
}
}