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syntax: Shrink enum Token and enum nonterminal

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`enum Token` was 192 bytes (64-bit), as pointed out by pnkfelix; the only
bloating variant being `INTERPOLATED(nonterminal)`.

Updating `enum nonterminal` to use ~ where variants included big types,
shrunk size_of(Token) to 32 bytes (64-bit).

I am unsure if the `nt_ident` variant should have an indirection, with
ast::ident being only 16 bytes (64-bit), but without this, enum Token
would be 40 bytes.

A dumb benchmark says that compilation time is unchanged, while peak
memory usage for compiling std.rs is down 3%

Before::

    $ time ./x86_64-unknown-linux-gnu/stage1/bin/rustc --cfg stage1 src/libstd/std.rs
    19.00user 0.39system 0:19.41elapsed 99%CPU (0avgtext+0avgdata 627820maxresident)k
    0inputs+28896outputs (0major+228665minor)pagefaults 0swaps
    $ time ./x86_64-unknown-linux-gnu/stage1/bin/rustc -O --cfg stage1 src/libstd/std.rs
    31.64user 0.34system 0:32.02elapsed 99%CPU (0avgtext+0avgdata 629876maxresident)k
    0inputs+22432outputs (0major+229411minor)pagefaults 0swaps

After::

    $ time ./x86_64-unknown-linux-gnu/stage1/bin/rustc --cfg stage1 src/libstd/std.rs
    19.07user 0.45system 0:19.55elapsed 99%CPU (0avgtext+0avgdata 609384maxresident)k
    0inputs+28896outputs (0major+221997minor)pagefaults 0swaps

    $ time ./x86_64-unknown-linux-gnu/stage1/bin/rustc -O --cfg stage1 src/libstd/std.rs
    31.90user 0.34system 0:32.28elapsed 99%CPU (0avgtext+0avgdata 612080maxresident)k
    0inputs+22432outputs (0major+223726minor)pagefaults 0swaps
This commit is contained in:
blake2-ppc 2013-08-09 19:55:15 +02:00
parent bf809768ee
commit 5cfad6fbae
4 changed files with 16 additions and 16 deletions
Download patch file Download diff file Expand all files Collapse all files

8
src/libsyntax/parse/token.rs
View file

@ -99,14 +99,14 @@ pub enum Token {
/// For interpolation during macro expansion.
pub enum nonterminal {
nt_item(@ast::item),
nt_block(ast::Block),
nt_block(~ast::Block),
nt_stmt(@ast::stmt),
nt_pat( @ast::pat),
nt_expr(@ast::expr),
nt_ty( ast::Ty),
nt_ident(ast::ident, bool),
nt_ty( ~ast::Ty),
nt_ident(~ast::ident, bool),
nt_attr(@ast::Attribute), // #[foo]
nt_path( ast::Path),
nt_path(~ast::Path),
nt_tt( @ast::token_tree), //needs @ed to break a circularity
nt_matchers(~[ast::matcher])
}