Don't spin expanding stmt macros.
If we can't make progress when parsing a macro expansion as a statement then we should just bail.
This alleviates the symptoms shown in e.g. #37113 and #37234 but it doesn't fix the problem that parsing invalid enum bodies (and others) leaves the parser in a crappy state.
I'm not sold on this strategy (checking `tokens_consumed`), so if anyone has a better idea, I'm all ears!
Most of the Rust community agrees that the vec! macro is clearer when
called using square brackets [] instead of regular brackets (). Most of
these ocurrences are from before macros allowed using different types of
brackets.
There is one left unchanged in a pretty-print test, as the pretty
printer still wants it to have regular brackets.
Avoid more allocations when compiling html5ever
These three commits reduce the number of allocations performed when compiling html5ever from 13.2M to 10.8M, which speeds up compilation by about 2%.
r? @nrc
If we can't make progress when parsing a macro expansion as a statement
then we should just bail.
This alleviates the symptoms shown in e.g. #37113 but it doesn't fix the
problem that parsing invalid enum bodies (and others) leaves the parser
in a crappy state.
Avoid some allocations in the macro parser
These three commits reduce the number of heap allocations done when compiling rustc-benchmarks/html5ever-2016-08-25 by 20%, from 16.5M to 13.3M. This speeds up (debug) compilation of it with a stage1 compiler by about 7%.
macros: fix partially consumed tokens in macro matchers
Fixes#37175.
This PR also avoids re-transcribing the tokens consumed by a matcher (and cloning the `TtReader` once per matcher), which improves expansion performance of the test case from #34630 by ~8%.
r? @nrc
macros 1.1: future proofing and cleanup
This PR
- uses the macro namespace for custom derives (instead of a dedicated custom derive namespace),
- relaxes the shadowing rules for `#[macro_use]`-imported custom derives to match the shadowing rules for ordinary `#[macro_use]`-imported macros, and
- treats custom derive `extern crate`s like empty modules so that we can eventually allow, for example, `extern crate serde_derive; use serde_derive::Serialize;` backwards compatibly.
r? @alexcrichton
This commit changes `ExtCtx::cfg()` so it returns a `CrateConfig`
reference instead of a clone. As a result, it also changes all of the
`cfg()` callsites to explicitly clone... except one, because the commit
also changes `macro_parser::parse()` to take `&CrateConfig`. This is
good, because that function can be hot, and `CrateConfig` is expensive
to clone.
This change almost halves the number of heap allocations done by rustc
for `html5ever` in rustc-benchmarks suite, which makes compilation 1.20x
faster.
Jeffrey Seyfried