This can be applied to statics and it will indicate that LLVM will attempt to
merge the constant in .data with other statics.
I have preliminarily applied this to all of the statics generated by the new
`ifmt!` syntax extension. I compiled a file with 1000 calls to `ifmt!` and a
separate file with 1000 calls to `fmt!` to compare the sizes, and the results
were:
fmt 310k
ifmt (before) 529k
ifmt (after) 202k
This now means that ifmt! is both faster and smaller than fmt!, yay!
env! aborts compilation of the specified environment variable is not
defined and takes an optional second argument containing a custom
error message. option_env! creates an Option<&'static str> containing
the value of the environment variable.
There are no run-pass tests that check the behavior when the environment
variable is defined since the test framework doesn't support setting
environment variables at compile time as opposed to runtime. However,
both env! and option_env! are used inside of rustc itself, which should
act as a sufficient test.
Fixes#2248.
env! aborts compilation of the specified environment variable is not
defined and takes an optional second argument containing a custom
error message. option_env! creates an Option<&'static str> containing
the value of the environment variable.
There are no run-pass tests that check the behavior when the environment
variable is defined since the test framework doesn't support setting
environment variables at compile time as opposed to runtime. However,
both env! and option_env! are used inside of rustc itself, which should
act as a sufficient test.
Close#2248
This is a reopening of #8182, although this removes any abuse of the compiler internals. Now it's just a pure syntax extension (hard coded what the attribute names are).
Some general clean-up relating to deriving:
- `TotalOrd` was too eager, and evaluated the `.cmp` call for every field, even if it could short-circuit earlier.
- the pointer types didn't have impls for `TotalOrd` or `TotalEq`.
- the Makefiles didn't reach deep enough into libsyntax for dependencies.
(Split out from https://github.com/mozilla/rust/pull/8258.)
- Made naming schemes consistent between Option, Result and Either
- Changed Options Add implementation to work like the maybe monad (return None if any of the inputs is None)
- Removed duplicate Option::get and renamed all related functions to use the term `unwrap` instead
Previously it would call:
f(sf1.cmp(&of1), f(sf2.cmp(&of2), ...))
(where s/of1 = 'self/other field 1', and f was
std::cmp::lexical_ordering)
This meant that every .cmp subcall got evaluated when calling a derived
TotalOrd.cmp.
This corrects this to use
let test = sf1.cmp(&of1);
if test == Equal {
let test = sf2.cmp(&of2);
if test == Equal {
// ...
} else {
test
}
} else {
test
}
This gives a lexical ordering by short-circuiting on the first comparison
that is not Equal.
This is preparation for removing `@fn`.
This does *not* use default methods yet, because I don't know
whether they work. If they do, a forthcoming PR will use them.
This also changes the precedence of `as`.
The pipes compiler produced data types that encoded efficient and safe
bounded message passing protocols between two endpoints. It was also
capable of producing unbounded protocols.
It was useful research but was arguably done before its proper time.
I am removing it for the following reasons:
* In practice we used it only for producing the `oneshot` protcol and
the unbounded `stream` protocol and all communication in Rust use those.
* The interface between the proto! macro and the standard library
has a large surface area and was difficult to maintain through
language and library changes.
* It is now written in an old dialect of Rust and generates code
which would likely be considered non-idiomatic.
* Both the compiler and the runtime are difficult to understand,
and likewise the relationship between the generated code and
the library is hard to understand. Debugging is difficult.
* The new scheduler implements `stream` and `oneshot` by hand
in a way that will be significantly easier to maintain.
This shouldn't be taken as an indication that 'channel protocols'
for Rust are not worth pursuing again in the future.
Concerned parties may include: @graydon, @pcwalton, @eholk, @bblum
The most likely candidates for closing are #7666, #3018, #3020, #7021, #7667, #7303, #3658, #3295.
The pipes compiler produced data types that encoded efficient and safe
bounded message passing protocols between two endpoints. It was also
capable of producing unbounded protocols.
It was useful research but was arguably done before its proper time.
I am removing it for the following reasons:
* In practice we used it only for producing the `oneshot` and `stream`
unbounded protocols and all communication in Rust use those.
* The interface between the proto! macro and the standard library
has a large surface area and was difficult to maintain through
language and library changes.
* It is now written in an old dialect of Rust and generates code
which would likely be considered non-idiomatic.
* Both the compiler and the runtime are difficult to understand,
and likewise the relationship between the generated code and
the library is hard to understand. Debugging is difficult.
* The new scheduler implements `stream` and `oneshot` by hand
in a way that will be significantly easier to maintain.
This shouldn't be taken as an indication that 'channel protocols'
for Rust are not worth pursuing again in the future.
Change the former repetition::
for 5.times { }
to::
do 5.times { }
.times() cannot be broken with `break` or `return` anymore; for those
cases, use a numerical range loop instead.
Assertions without a message get a generated message that consists of a
prefix plus the stringified expression that is being asserted. That
prefix is currently a unique string, while a static string would be
sufficient and needs less code.
Assertions without a message get a generated message that consists of a
prefix plus the stringified expression that is being asserted. That
prefix is currently a unique string, while a static string would be
sufficient and needs less code.
Renamed bytes_iter to byte_iter to match other iterators
Refactored str Iterators to use DoubleEnded Iterators and typedefs instead of wrapper structs
Reordered the Iterator section
Whitespace fixup
Moved clunky `each_split_within` function to the one place in the tree where it's actually needed
Replaced all block doccomments in str with line doccomments
Contiunation of naming cleanup in `libsyntax::ast`:
```rust
ast::node_id => ast::NodeId
ast::local_crate => ast::LOCAL_CRATE
ast::crate_node_id => ast::CRATE_NODE_ID
ast::blk_check_mode => ast::BlockCheckMode
ast::ty_field => ast::TypeField
ast::ty_method => ast::TypeMethod
```
Also moved span field directly into `TypeField` struct and cleaned up overlooked `ast::CrateConfig` renamings from last pull request.
Cheers,
Michael
`crate => Crate`
`local => Local`
`blk => Block`
`crate_num => CrateNum`
`crate_cfg => CrateConfig`
Also, Crate and Local are not wrapped in spanned<T> anymore.
This does a number of things, but especially dramatically reduce the
number of allocations performed for operations involving attributes/
meta items:
- Converts ast::meta_item & ast::attribute and other associated enums
to CamelCase.
- Converts several standalone functions in syntax::attr into methods,
defined on two traits AttrMetaMethods & AttributeMethods. The former
is common to both MetaItem and Attribute since the latter is a thin
wrapper around the former.
- Deletes functions that are unnecessary due to iterators.
- Converts other standalone functions to use iterators and the generic
AttrMetaMethods rather than allocating a lot of new vectors (e.g. the
old code would have to allocate a new vector to use functions that
operated on &[meta_item] on &[attribute].)
- Moves the core algorithm of the #[cfg] matching to syntax::attr,
similar to find_inline_attr and find_linkage_metas.
This doesn't have much of an effect on the speed of #[cfg] stripping,
despite hugely reducing the number of allocations performed; presumably
most of the time is spent in the ast folder rather than doing attribute
checks.
Also fixes the Eq instance of MetaItem_ to correctly ignore spans, so
that `rustc --cfg 'foo(bar)'` now works.
This does a number of things, but especially dramatically reduce the
number of allocations performed for operations involving attributes/
meta items:
- Converts ast::meta_item & ast::attribute and other associated enums
to CamelCase.
- Converts several standalone functions in syntax::attr into methods,
defined on two traits AttrMetaMethods & AttributeMethods. The former
is common to both MetaItem and Attribute since the latter is a thin
wrapper around the former.
- Deletes functions that are unnecessary due to iterators.
- Converts other standalone functions to use iterators and the generic
AttrMetaMethods rather than allocating a lot of new vectors (e.g. the
old code would have to allocate a new vector to use functions that
operated on &[meta_item] on &[attribute].)
- Moves the core algorithm of the #[cfg] matching to syntax::attr,
similar to find_inline_attr and find_linkage_metas.
This doesn't have much of an effect on the speed of #[cfg] stripping,
despite hugely reducing the number of allocations performed; presumably
most of the time is spent in the ast folder rather than doing attribute
checks.
Also fixes the Eq instance of MetaItem_ to correctly ignore spaces, so
that `rustc --cfg 'foo(bar)'` now works.
