Auto merge of #35340 - michaelwoerister:incr-comp-cli-args, r=nikomatsakis

Take commandline arguments into account for incr. comp.

Implements the conservative strategy described in https://github.com/rust-lang/rust/issues/33727.

From now one, every time a new commandline option is added, one has to specify if it influences the incremental compilation cache. I've tried to implement this as automatic as possible: One just has to added either the `[TRACKED]` or the `[UNTRACKED]` marker next to the field. The `Options`, `CodegenOptions`, and `DebuggingOptions` definitions in `session::config` show plenty of examples.

The PR removes some cruft from `session::config::Options`, mostly unnecessary copies of flags also present in `DebuggingOptions` or `CodeGenOptions` in the same struct.

One notable removal is the `cfg` field that contained the values passed via `--cfg` commandline arguments. I chose to remove it because (1) its content is only a subset of what later is stored in `hir::Crate::config` and it's pretty likely that reading the cfgs from `Options` would not be what you wanted, and (2) we could not incorporate it into the dep-tracking hash of the `Options` struct because of how the test framework works, leaving us with a piece of untracked but vital data.

It is now recommended (just as before) to access the crate config via the `krate()` method in the HIR map.

Because the `cfg` field is not present in the `Options` struct any more, some methods in the `CompilerCalls` trait now take the crate config as an explicit parameter -- which might constitute a breaking change for plugin authors.

1 files changed, 30 insertions, 0 deletions

diff --git a/src/test/incremental/commandline-args.rs b/src/test/incremental/commandline-args.rs
new file mode 100644
index 00000000000..95187b825be
--- /dev/null
+++ b/src/test/incremental/commandline-args.rs
@@ -0,0 +1,30 @@
+// Copyright 2016 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.
+
+// Test that changing a tracked commandline argument invalidates
+// the cache while changing an untracked one doesn't.
+
+// revisions:rpass1 rpass2 rpass3
+
+#![feature(rustc_attrs)]
+
+#![rustc_partition_translated(module="commandline_args", cfg="rpass2")]
+#![rustc_partition_reused(module="commandline_args", cfg="rpass3")]
+
+// Between revisions 1 and 2, we are changing the debuginfo-level, which should
+// invalidate the cache. Between revisions 2 and 3, we are adding `--verbose`
+// which should have no effect on the cache:
+//[rpass1] compile-flags: -C debuginfo=0
+//[rpass2] compile-flags: -C debuginfo=2
+//[rpass3] compile-flags: -C debuginfo=2 --verbose
+
+pub fn main() {
+    // empty
+}