Auto merge of #34956 - nikomatsakis:incr-comp-o-files, r=mw

Enable reuse of `.o` files if nothing has changed

This PR completes a first "spike" for incremental compilation by enabling us to reuse `.o` files when nothing has changed. When in incr. mode, we will save `.o` files into the temporary directory, then copy them back out again if they are still valid. The code is still a bit rough but it does seem to work. =)

r? @michaelwoerister

Fixes #34036
Fixes #34037
Fixes #34038

7 files changed, 262 insertions, 2 deletions

diff --git a/src/test/incremental/rlib_cross_crate/auxiliary/a.rs b/src/test/incremental/rlib_cross_crate/auxiliary/a.rs
new file mode 100644
index 00000000000..ff5fd634714
--- /dev/null
+++ b/src/test/incremental/rlib_cross_crate/auxiliary/a.rs
@@ -0,0 +1,25 @@
+// 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.
+
+// no-prefer-dynamic
+
+#![crate_type="rlib"]
+
+#[cfg(rpass1)]
+pub type X = u32;
+
+#[cfg(rpass2)]
+pub type X = i32;
+
+// this version doesn't actually change anything:
+#[cfg(rpass3)]
+pub type X = i32;
+
+pub type Y = char;
diff --git a/src/test/incremental/rlib_cross_crate/b.rs b/src/test/incremental/rlib_cross_crate/b.rs
new file mode 100644
index 00000000000..55398370425
--- /dev/null
+++ b/src/test/incremental/rlib_cross_crate/b.rs
@@ -0,0 +1,38 @@
+// 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.
+
+// Same test as `type_alias_cross_crate`, but with
+// `no-prefer-dynamic`, ensuring that we test what happens when we
+// build rlibs (before we were only testing dylibs, which meant we
+// didn't realize we had to preserve a `bc` file as well).
+
+// aux-build:a.rs
+// revisions:rpass1 rpass2 rpass3
+// no-prefer-dynamic
+
+
+#![feature(rustc_attrs)]
+
+extern crate a;
+
+#[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+#[rustc_clean(label="TypeckItemBody", cfg="rpass3")]
+pub fn use_X() -> u32 {
+    let x: a::X = 22;
+    x as u32
+}
+
+#[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+#[rustc_clean(label="TypeckItemBody", cfg="rpass3")]
+pub fn use_Y() {
+    let x: a::Y = 'c';
+}
+
+pub fn main() { }
diff --git a/src/test/incremental/spike-neg1.rs b/src/test/incremental/spike-neg1.rs
new file mode 100644
index 00000000000..b00c68a184e
--- /dev/null
+++ b/src/test/incremental/spike-neg1.rs
@@ -0,0 +1,62 @@
+// 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.
+
+// A variant of the first "spike" test that serves to test the
+// `rustc_partition_reused` and `rustc_partition_translated` tests.
+// Here we change and say that the `x` module will be reused (when in
+// fact it will not), and then indicate that the test itself
+// should-fail (because an error will be reported, and hence the
+// revision rpass2 will not compile, despite being named rpass).
+
+// revisions:rpass1 rpass2
+// should-fail
+
+#![feature(rustc_attrs)]
+
+#![rustc_partition_reused(module="spike_neg1", cfg="rpass2")]
+#![rustc_partition_reused(module="spike_neg1-x", cfg="rpass2")] // this is wrong!
+#![rustc_partition_reused(module="spike_neg1-y", cfg="rpass2")]
+
+mod x {
+    pub struct X {
+        x: u32, y: u32,
+    }
+
+    #[cfg(rpass1)]
+    fn make() -> X {
+        X { x: 22, y: 0 }
+    }
+
+    #[cfg(rpass2)]
+    fn make() -> X {
+        X { x: 11, y: 11 }
+    }
+
+    pub fn new() -> X {
+        make()
+    }
+
+    pub fn sum(x: &X) -> u32 {
+        x.x + x.y
+    }
+}
+
+mod y {
+    use x;
+
+    pub fn assert_sum() -> bool {
+        let x = x::new();
+        x::sum(&x) == 22
+    }
+}
+
+pub fn main() {
+    y::assert_sum();
+}
diff --git a/src/test/incremental/spike-neg2.rs b/src/test/incremental/spike-neg2.rs
new file mode 100644
index 00000000000..472d11d7f90
--- /dev/null
+++ b/src/test/incremental/spike-neg2.rs
@@ -0,0 +1,62 @@
+// 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.
+
+// A variant of the first "spike" test that serves to test the
+// `rustc_partition_reused` and `rustc_partition_translated` tests.
+// Here we change and say that the `y` module will be translated (when
+// in fact it will not), and then indicate that the test itself
+// should-fail (because an error will be reported, and hence the
+// revision rpass2 will not compile, despite being named rpass).
+
+// revisions:rpass1 rpass2
+// should-fail
+
+#![feature(rustc_attrs)]
+
+#![rustc_partition_reused(module="spike_neg2", cfg="rpass2")]
+#![rustc_partition_translated(module="spike_neg2-x", cfg="rpass2")]
+#![rustc_partition_translated(module="spike_neg2-y", cfg="rpass2")] // this is wrong!
+
+mod x {
+    pub struct X {
+        x: u32, y: u32,
+    }
+
+    #[cfg(rpass1)]
+    fn make() -> X {
+        X { x: 22, y: 0 }
+    }
+
+    #[cfg(rpass2)]
+    fn make() -> X {
+        X { x: 11, y: 11 }
+    }
+
+    pub fn new() -> X {
+        make()
+    }
+
+    pub fn sum(x: &X) -> u32 {
+        x.x + x.y
+    }
+}
+
+mod y {
+    use x;
+
+    pub fn assert_sum() -> bool {
+        let x = x::new();
+        x::sum(&x) == 22
+    }
+}
+
+pub fn main() {
+    y::assert_sum();
+}
diff --git a/src/test/incremental/spike.rs b/src/test/incremental/spike.rs
new file mode 100644
index 00000000000..68af20d4191
--- /dev/null
+++ b/src/test/incremental/spike.rs
@@ -0,0 +1,63 @@
+// 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.
+
+// A first "spike" for incremental compilation: here, we change the
+// content of the `make` function, and we find that we can reuse the
+// `y` module entirely (but not the `x` module).
+
+// revisions:rpass1 rpass2
+
+#![feature(rustc_attrs)]
+
+#![rustc_partition_reused(module="spike", cfg="rpass2")]
+#![rustc_partition_translated(module="spike-x", cfg="rpass2")]
+#![rustc_partition_reused(module="spike-y", cfg="rpass2")]
+
+mod x {
+    pub struct X {
+        x: u32, y: u32,
+    }
+
+    #[cfg(rpass1)]
+    fn make() -> X {
+        X { x: 22, y: 0 }
+    }
+
+    #[cfg(rpass2)]
+    fn make() -> X {
+        X { x: 11, y: 11 }
+    }
+
+    #[rustc_dirty(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="ItemSignature", cfg="rpass2")]
+    pub fn new() -> X {
+        make()
+    }
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    #[rustc_clean(label="ItemSignature", cfg="rpass2")]
+    pub fn sum(x: &X) -> u32 {
+        x.x + x.y
+    }
+}
+
+mod y {
+    use x;
+
+    #[rustc_clean(label="TypeckItemBody", cfg="rpass2")]
+    pub fn assert_sum() -> bool {
+        let x = x::new();
+        x::sum(&x) == 22
+    }
+}
+
+pub fn main() {
+    y::assert_sum();
+}
diff --git a/src/test/run-make/execution-engine/test.rs b/src/test/run-make/execution-engine/test.rs
index 2e90b518432..b58295d47f2 100644
--- a/src/test/run-make/execution-engine/test.rs
+++ b/src/test/run-make/execution-engine/test.rs
@@ -20,6 +20,7 @@ extern crate rustc_metadata;
 extern crate rustc_resolve;
 extern crate rustc_errors;
 extern crate rustc_errors as errors;
+extern crate rustc_trans;
 #[macro_use] extern crate syntax;
 
 use std::ffi::{CStr, CString};
@@ -37,6 +38,7 @@ use rustc::session::build_session;
 use rustc_driver::{driver, abort_on_err};
 use rustc_resolve::MakeGlobMap;
 use rustc_metadata::cstore::CStore;
+use rustc_trans::ModuleSource;
 use libc::c_void;
 
 use rustc_errors::registry::Registry;
@@ -261,7 +263,10 @@ fn compile_program(input: &str, sysroot: PathBuf)
                 .filter_map(|(_, p)| p).collect();
 
             assert_eq!(trans.modules.len(), 1);
-            let llmod = trans.modules[0].llmod;
+            let llmod = match trans.modules[0].source {
+                ModuleSource::Preexisting(_) => unimplemented!(),
+                ModuleSource::Translated(llvm) => llvm.llmod,
+            };
 
             // Workaround because raw pointers do not impl Send
             let modp = llmod as usize;
diff --git a/src/test/run-make/llvm-phase/test.rs b/src/test/run-make/llvm-phase/test.rs
index 402b5ed8355..19e410fef53 100644
--- a/src/test/run-make/llvm-phase/test.rs
+++ b/src/test/run-make/llvm-phase/test.rs
@@ -13,11 +13,13 @@
 extern crate rustc;
 extern crate rustc_driver;
 extern crate rustc_llvm;
+extern crate rustc_trans;
 #[macro_use] extern crate syntax;
 extern crate getopts;
 
 use rustc_driver::{CompilerCalls, Compilation};
 use rustc_driver::driver::CompileController;
+use rustc_trans::ModuleSource;
 use rustc::session::Session;
 use syntax::codemap::FileLoader;
 use std::io;
@@ -51,7 +53,10 @@ impl<'a> CompilerCalls<'a> for JitCalls {
             state.session.abort_if_errors();
             let trans = state.trans.unwrap();
             assert_eq!(trans.modules.len(), 1);
-            let rs_llmod = trans.modules[0].llmod;
+            let rs_llmod = match trans.modules[0].source {
+                ModuleSource::Preexisting(_) => unimplemented!(),
+                ModuleSource::Translated(llvm) => llvm.llmod,
+            };
             unsafe { rustc_llvm::LLVMDumpModule(rs_llmod) };
         });
         cc