This avoids a biggish eight-byte `tag_table_id` tag in favor of
autoserialized integer tags, which are smaller and can be later
used to encode them in the optimal number of bytes. `NodeId` was
u32 after all.
Previously:
<------------- len1 -------------->
tag_table_* <len1> tag_table_id 88 <nodeid in 8 bytes>
tag_table_val <len2> <actual data>
<-- len2 --->
Now:
<--------------- len --------------->
tag_table_* <len> U32 <nodeid in 4 bytes> <actual data>
We try to move the data when the length can be encoded in
the much smaller number of bytes. This interferes with indices and
type abbreviations however, so this commit introduces a public
interface to get and mark a "stable" (i.e. not affected by
relaxation) position of the current pointer.
The relaxation logic only moves a small data, currently at most
256 bytes, as moving the data can be costly. There might be
further opportunities to allow more relaxation by moving fields
around, which I didn't seriously try.
They replace the existing `EsEnumVid`, `EsVecLen` and `EsMapLen`
tags altogether; the meaning of them can be easily inferred
from the enclosing tag. It also has an added benefit of
encodings for smaller variant ids or lengths being more compact
(5 bytes to 2 bytes).
For the reference, while it is designed to be selectively enabled,
it was essentially enabled throughout every snapshot and nightly
as far as I can tell. This makes the usefulness of `EsLabel` itself
questionable, as it was quite rare that `EsLabel` broke the build.
It had consumed about 20~30% of metadata (!) and so this should be
a huge win.
It doesn't serve any useful purpose. It *might* be useful when
there are some tags that are generated by `Encodable` and
not delimited by any tags, but IIUC it's not the case.
Previous:
<-------------------- len1 ------------------->
EsEnum <len1> EsEnumVid <vid> EsEnumBody <len2> <arg1> <arg2>
<--- len2 -->
Now:
<----------- len1 ---------->
EsEnum <len1> EsEnumVid <vid> <arg1> <arg2>
Many auto-serialization tags are fixed-size (note: many ordinary
tags are also fixed-size but for now this commit ignores them),
so having an explicit length is a waste. This moves any
auto-serialization tags with an implicit length before other tags,
so a test for them is easy. A preliminary experiment shows this
has at least 1% gain over the status quo.
EBML tags are encoded in a variable-length unsigned int (vuint),
which is clever but causes some tags to be encoded in two bytes
while there are really about 180 tags or so. Assuming that there
wouldn't be, say, over 1,000 tags in the future, we can use much
more efficient encoding scheme. The new scheme should support
at most 4,096 tags anyway.
This also flattens a scattered tag namespace (did you know that
0xa9 is followed by 0xb0?) and makes a room for autoserialized tags
in 0x00 through 0x1f.
They are, with a conjunction of `start_tag` and `end_tag`, commonly
used to write a document with a binary data of known size. However
the use of `start_tag` makes the length always 4 bytes long, which
is almost not optimal (requiring the relaxation step to remedy).
Directly using `wr_tagged_*` methods is better for both readability
and resulting metadata size.
This commits blanket marks the API of the `std::process` module as `#[stable]`.
The module's API is very similar to the old `std::old_io::process` API and has
generally had quite a bit of time to bake both before and after the new module
landed.
Remove the synthetic \"region bound\" from closures and instead update how
type-outlives works for closure types so that it ensures that all upvars
outlive the region in question. This gives the same guarantees but
without introducing artificial regions (and gives better error messages
to boot). This is refactoring towards #3696.
r? @pnkfelix
type-outlives works for closure types so that it ensures that all upvars
outlive the region in question. This gives the same guarantees but
without introducing artificial regions (and gives better error messages
to boot).
This is an implementation of RFC 899 and adds stdio functionality to the new
`std::io` module. Details of the API can be found on the RFC, but from a high
level:
* `io::{stdin, stdout, stderr}` constructors are now available. There are also
`*_raw` variants for unbuffered and unlocked access.
* All handles are globally shared (excluding raw variants).
* The stderr handle is no longer buffered.
* All handles can be explicitly locked (excluding the raw variants).
The `print!` and `println!` machinery has not yet been hooked up to these
streams just yet. The `std::fmt::output` module has also not yet been
implemented as part of this commit.
This commits blanket marks the API of the `std::process` module as `#[stable]`.
The module's API is very similar to the old `std::old_io::process` API and has
generally had quite a bit of time to bake both before and after the new module
landed.
The one modification made to the API is that `Stdio::capture` is now named
`stdio::piped`.
[breaking-change]
... objects
For method calls through trait objects, we currently generate the llvm
function argument attributes using the non-opaque method signature that
still has the trait object fat pointer for the self pointer. This leads
to attributes that are plain wrong, e.g. noalias. As we don't know
anything about the concrete type of the underlying object, we must
replace the self argument with an opaque i8 pointer before applying the
attributes.
this is the same problem as openbsd (#22792).
without the patch, liblibc don't build.
@mneumann please comment.
I have encountered this problem while building some rust libs with `target=x86_64-unknown-dragonfly` (while working on #22794)
Check for unbounded recursion during dropck.
Such recursion can be introduced by the erroneous use of non-regular types (aka types employing polymorphic recursion), which Rust does not support.
Fix#22443
For method calls through trait objects, we currently generate the llvm
function argument attributes using the non-opaque method signature that
still has the trait object fat pointer for the self pointer. This leads
to attributes that are plain wrong, e.g. noalias. As we don't know
anything about the concrete type of the underlying object, we must
replace the self argument with an opaque i8 pointer before applying the
attributes.
Count recursion across phantom data separately from all recursion,
and treat `Box<T>` just as if it were carrying `PhantomData<T>`.
(Regression tests are in followup commit.)
The practical effect of this is just to increment the `xref_depth`
counter, the same way that `Vec` and other types carrying
`PhantomData` do.
This is an implementation of RFC 899 and adds stdio functionality to the new
`std::io` module. Details of the API can be found on the RFC, but from a high
level:
* `io::{stdin, stdout, stderr}` constructors are now available. There are also
`*_raw` variants for unbuffered and unlocked access.
* All handles are globally shared (excluding raw variants).
* The stderr handle is no longer buffered.
* All handles can be explicitly locked (excluding the raw variants).
The `print!` and `println!` machinery has not yet been hooked up to these
streams just yet. The `std::fmt::output` module has also not yet been
implemented as part of this commit.
