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Auto merge of #71815 - Mark-Simulacrum:no-llvm-rebuild, r=jonas-schievink

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Don't bust caches on x.py check/build switches

Fixes #71152
This commit is contained in:
bors 2020-05-03 02:58:00 +00:00
commit 0a675c5e02
4 changed files with 89 additions and 51 deletions
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12
src/bootstrap/builder.rs
View file

@ -765,9 +765,17 @@ impl<'a> Builder<'a> {
}
// Set a flag for `check`/`clippy`/`fix`, so that certain build
// scripts can do less work (e.g. not building/requiring LLVM).
// scripts can do less work (i.e. not building/requiring LLVM).
if cmd == "check" || cmd == "clippy" || cmd == "fix" {
cargo.env("RUST_CHECK", "1");
// If we've not yet built LLVM, or it's stale, then bust
// the librustc_llvm cache. That will always work, even though it
// may mean that on the next non-check build we'll need to rebuild
// librustc_llvm. But if LLVM is stale, that'll be a tiny amount
// of work comparitively, and we'd likely need to rebuild it anyway,
// so that's okay.
if crate::native::prebuilt_llvm_config(self, target).is_err() {
cargo.env("RUST_CHECK", "1");
}
}
let stage = if compiler.stage == 0 && self.local_rebuild {

10
src/bootstrap/compile.rs
View file

@ -517,9 +517,13 @@ pub fn rustc_cargo_env(builder: &Builder<'_>, cargo: &mut Cargo, target: Interne
// librustc_llvm and librustc_codegen_llvm.
//
// Note that this is disabled if LLVM itself is disabled or we're in a check
// build, where if we're in a check build there's no need to build all of
// LLVM and such.
if builder.config.llvm_enabled() && builder.kind != Kind::Check {
// build. If we are in a check build we still go ahead here presuming we've
// detected that LLVM is alreay built and good to go which helps prevent
// busting caches (e.g. like #71152).
if builder.config.llvm_enabled()
&& (builder.kind != Kind::Check
|| crate::native::prebuilt_llvm_config(builder, target).is_ok())
{
if builder.is_rust_llvm(target) {
cargo.env("LLVM_RUSTLLVM", "1");
}

116
src/bootstrap/native.rs
View file

@ -24,6 +24,72 @@ use crate::util::{self, exe};
use crate::GitRepo;
use build_helper::up_to_date;
pub struct Meta {
stamp: HashStamp,
build_llvm_config: PathBuf,
out_dir: PathBuf,
root: String,
}
// This returns whether we've already previously built LLVM.
//
// It's used to avoid busting caches during x.py check -- if we've already built
// LLVM, it's fine for us to not try to avoid doing so.
//
// This will return the llvm-config if it can get it (but it will not build it
// if not).
pub fn prebuilt_llvm_config(
builder: &Builder<'_>,
target: Interned<String>,
) -> Result<PathBuf, Meta> {
// If we're using a custom LLVM bail out here, but we can only use a
// custom LLVM for the build triple.
if let Some(config) = builder.config.target_config.get(&target) {
if let Some(ref s) = config.llvm_config {
check_llvm_version(builder, s);
return Ok(s.to_path_buf());
}
}
let root = "src/llvm-project/llvm";
let out_dir = builder.llvm_out(target);
let mut llvm_config_ret_dir = builder.llvm_out(builder.config.build);
if !builder.config.build.contains("msvc") || builder.config.ninja {
llvm_config_ret_dir.push("build");
}
llvm_config_ret_dir.push("bin");
let build_llvm_config = llvm_config_ret_dir.join(exe("llvm-config", &*builder.config.build));
let stamp = out_dir.join("llvm-finished-building");
let stamp = HashStamp::new(stamp, builder.in_tree_llvm_info.sha());
if builder.config.llvm_skip_rebuild && stamp.path.exists() {
builder.info(
"Warning: \
Using a potentially stale build of LLVM; \
This may not behave well.",
);
return Ok(build_llvm_config);
}
if stamp.is_done() {
if stamp.hash.is_none() {
builder.info(
"Could not determine the LLVM submodule commit hash. \
Assuming that an LLVM rebuild is not necessary.",
);
builder.info(&format!(
"To force LLVM to rebuild, remove the file `{}`",
stamp.path.display()
));
}
return Ok(build_llvm_config);
}
Err(Meta { stamp, build_llvm_config, out_dir, root: root.into() })
}
#[derive(Debug, Copy, Clone, Hash, PartialEq, Eq)]
pub struct Llvm {
pub target: Interned<String>,
@ -46,51 +112,11 @@ impl Step for Llvm {
fn run(self, builder: &Builder<'_>) -> PathBuf {
let target = self.target;
// If we're using a custom LLVM bail out here, but we can only use a
// custom LLVM for the build triple.
if let Some(config) = builder.config.target_config.get(&target) {
if let Some(ref s) = config.llvm_config {
check_llvm_version(builder, s);
return s.to_path_buf();
}
}
let root = "src/llvm-project/llvm";
let out_dir = builder.llvm_out(target);
let mut llvm_config_ret_dir = builder.llvm_out(builder.config.build);
if !builder.config.build.contains("msvc") || builder.config.ninja {
llvm_config_ret_dir.push("build");
}
llvm_config_ret_dir.push("bin");
let build_llvm_config =
llvm_config_ret_dir.join(exe("llvm-config", &*builder.config.build));
let stamp = out_dir.join("llvm-finished-building");
let stamp = HashStamp::new(stamp, builder.in_tree_llvm_info.sha());
if builder.config.llvm_skip_rebuild && stamp.path.exists() {
builder.info(
"Warning: \
Using a potentially stale build of LLVM; \
This may not behave well.",
);
return build_llvm_config;
}
if stamp.is_done() {
if stamp.hash.is_none() {
builder.info(
"Could not determine the LLVM submodule commit hash. \
Assuming that an LLVM rebuild is not necessary.",
);
builder.info(&format!(
"To force LLVM to rebuild, remove the file `{}`",
stamp.path.display()
));
}
return build_llvm_config;
}
let Meta { stamp, build_llvm_config, out_dir, root } =
match prebuilt_llvm_config(builder, target) {
Ok(p) => return p,
Err(m) => m,
};
builder.info(&format!("Building LLVM for {}", target));
t!(stamp.remove());

2
src/librustc_llvm/build.rs
View file

@ -15,9 +15,9 @@ fn detect_llvm_link() -> (&'static str, &'static str) {
}
fn main() {
println!("cargo:rerun-if-env-changed=RUST_CHECK");
if env::var_os("RUST_CHECK").is_some() {
// If we're just running `check`, there's no need for LLVM to be built.
println!("cargo:rerun-if-env-changed=RUST_CHECK");
return;
}