Auto merge of #32016 - nikomatsakis:incr-comp-save, r=mw

Save/load incremental compilation dep graph

Contains the code to serialize/deserialize the dep graph to disk between executions. We also hash the item contents and compare to the new hashes. Also includes a unit test harness. There are definitely some known limitations, such as https://github.com/rust-lang/rust/issues/32014 and https://github.com/rust-lang/rust/issues/32015, but I am leaving those for follow-up work.

Note that this PR builds on https://github.com/rust-lang/rust/pull/32007, so the overlapping commits can be excluded from review.

r? @michaelwoerister

src/test/compile-fail/dep-graph-assoc-type-trans.rs

@@ -11,7 +11,7 @@
 // Test that when a trait impl changes, fns whose body uses that trait
 // must also be recompiled.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(warnings)]

src/test/compile-fail/dep-graph-caller-callee.rs

@@ -11,7 +11,7 @@
 // Test that immediate callers have to change when callee changes, but
 // not callers' callers.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(dead_code)]

src/test/compile-fail/dep-graph-struct-signature.rs

@@ -11,7 +11,7 @@
 // Test cases where a changing struct appears in the signature of fns
 // and methods.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(dead_code)]

src/test/compile-fail/dep-graph-trait-impl-two-traits-same-method.rs

@@ -11,7 +11,7 @@
 // Test that adding an impl to a trait `Foo` DOES affect functions
 // that only use `Bar` if they have methods in common.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(dead_code)]

src/test/compile-fail/dep-graph-trait-impl-two-traits.rs

@@ -11,7 +11,7 @@
 // Test that adding an impl to a trait `Foo` does not affect functions
 // that only use `Bar`, so long as they do not have methods in common.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(warnings)]

src/test/compile-fail/dep-graph-trait-impl.rs

@@ -11,7 +11,7 @@
 // Test that when a trait impl changes, fns whose body uses that trait
 // must also be recompiled.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(warnings)]

src/test/compile-fail/dep-graph-unrelated.rs

@@ -10,7 +10,7 @@
 
 // Test that two unrelated functions have no trans dependency.
 
-// compile-flags: -Z incr-comp
+// compile-flags: -Z query-dep-graph
 
 #![feature(rustc_attrs)]
 #![allow(dead_code)]

src/test/incremental/dirty_clean.rs

@@ -0,0 +1,53 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// revisions: rpass1 cfail2
+
+#![allow(warnings)]
+#![feature(rustc_attrs)]
+
+// Sanity check for the dirty-clean system. Give the opposite
+// annotations that we expect to see, so that we check that errors are
+// reported.
+
+fn main() { }
+
+mod x {
+    #[cfg(rpass1)]
+    pub fn x() -> usize {
+        22
+    }
+
+    #[cfg(cfail2)]
+    pub fn x() -> u32 {
+        22
+    }
+}
+
+mod y {
+    use x;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="cfail2")]
+    #[rustc_clean(label="TransCrateItem", cfg="cfail2")]
+    pub fn y() {
+        //[cfail2]~^ ERROR `TypeckItemBody("y::y")` not found in dep graph, but should be clean
+        //[cfail2]~| ERROR `TransCrateItem("y::y")` not found in dep graph, but should be clean
+        x::x();
+    }
+}
+
+mod z {
+    #[rustc_dirty(label="TypeckItemBody", cfg="cfail2")]
+    #[rustc_dirty(label="TransCrateItem", cfg="cfail2")]
+    pub fn z() {
+        //[cfail2]~^ ERROR `TypeckItemBody("z::z")` found in dep graph, but should be dirty
+        //[cfail2]~| ERROR `TransCrateItem("z::z")` found in dep graph, but should be dirty
+    }
+}

src/test/incremental/hello_world.rs

@@ -0,0 +1,46 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// revisions: rpass1 rpass2
+
+#![allow(warnings)]
+#![feature(rustc_attrs)]
+
+fn main() { }
+
+mod x {
+    #[cfg(rpass1)]
+    pub fn x() -> i32 {
+        1
+    }
+
+    #[cfg(rpass2)]
+    pub fn x() -> i32 {
+        2
+    }
+}
+
+mod y {
+    use x;
+
+    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    pub fn y() {
+        x::x();
+    }
+}
+
+mod z {
+    use y;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    pub fn z() {
+        y::y();
+    }
+}

src/test/incremental/string_constant.rs

@@ -0,0 +1,58 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// revisions: rpass1 rpass2
+
+#![allow(warnings)]
+#![feature(rustc_attrs)]
+
+// Here the only thing which changes is the string constant in `x`.
+// Therefore, the compiler deduces (correctly) that typeck is not
+// needed even for callers of `x`.
+//
+// It is not entirely clear why `TransCrateItem` invalidates `y` and
+// `z`, actually, I think it's because of the structure of
+// trans. -nmatsakis
+
+fn main() { }
+
+mod x {
+    #[cfg(rpass1)]
+    pub fn x() {
+        println!("1");
+    }
+
+    #[cfg(rpass2)]
+    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_dirty(label="TransCrateItem", cfg="rpass2")]
+    pub fn x() {
+        println!("2");
+    }
+}
+
+mod y {
+    use x;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="TransCrateItem", cfg="rpass2")]
+    pub fn y() {
+        x::x();
+    }
+}
+
+mod z {
+    use y;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="TransCrateItem", cfg="rpass2")]
+    pub fn z() {
+        y::y();
+    }
+}

src/test/run-make/execution-engine/test.rs

@@ -239,7 +239,7 @@ fn compile_program(input: &str, sysroot: PathBuf)
 
         let krate = driver::assign_node_ids(&sess, krate);
         let lcx = LoweringContext::new(&sess, Some(&krate));
-        let dep_graph = DepGraph::new(sess.opts.build_dep_graph);
+        let dep_graph = DepGraph::new(sess.opts.build_dep_graph());
         let mut hir_forest = ast_map::Forest::new(lower_crate(&lcx, &krate), dep_graph);
         let arenas = ty::CtxtArenas::new();
         let ast_map = driver::make_map(&sess, &mut hir_forest);