The #[phase(syntax,link)] attribute on `extern crate std` needs to be an
outer attribute so it can pretty-print properly.
Also add `#![no_std]` and `#[feature(phase)]` so compiling the
pretty-printed source will work.
One of the long-term goals of the libstd facade is to move the collections
library underneath the standard library. This would imply that libcollections
today would invert its dependency with libstd.
One of the primary blockers for doing this is the HashMap collection. Of its two
major dependencies, hashing and randomness, this commit is the first step in
dealing with hashing.
When moving the hash module beneath libstd, it must break its primary dependence
on the io::Writer trait (used as the hashing state). The proposed strategy for
breaking this dependence is taking a similar path as core::fmt, which is to have
the hash module define its own "writer trait". This trait would be similar to
std::io::Writer, except that it would not return errors and it would have fewer
convenience methods.
The Hash trait today has its type parameter behind a feature gate (default type
parameters), so this pending change will likely break no code which hasn't opted
in to the feature gate. The SipState struct will lose its implementation of
io::Writer, but it will regain similar methods for dealing with writing data.
This change specifically prepares for the hash migration by modifying
deriving(Hash) to use the std:#️⃣:Writer bound instead of the std::io::Writer
bound. This bound is currently wired to std::io::Writer, but after a snapshot it
will have no need to be wired to the io writer trait.
The changes to flowgraph make invalid invocations slightly more forgiving by (trying to) provide slightly more information and by avoiding the ICE message.
This defers to .fatal and .span_fatal for errors (rather than `fail!`
which prints the ICE message). It also adds the span lookup when an id
doesn't correspond to a block, to show what it is pointing at.
It also makes the argument parser slightly looser, so that passing
`--pretty flowgraph` recognises the `flowgraph` part and suggests to use
an integer.
Rng.choose() is used so rarely that it doesn't necessitate having two
methods, especially since the failing, non-option variant also requires
Clone.
[breaking-change]
Excluding the functions inherited from the cast module last week (with marked
stability levels), these functions received the following treatment.
* size_of - this method has become #[stable]
* nonzero_size_of/nonzero_size_of_val - these methods have been removed
* min_align_of - this method is now #[stable]
* pref_align_of - this method has been renamed without the
`pref_` prefix, and it is the "default alignment" now. This decision is in line
with what clang does (see url linked in comment on function). This function
is now #[stable].
* init - renamed to zeroed and marked #[stable]
* uninit - marked #[stable]
* move_val_init - renamed to overwrite and marked #[stable]
* {from,to}_{be,le}{16,32,64} - all functions marked #[stable]
* swap/replace/drop - marked #[stable]
* size_of_val/min_align_of_val/align_of_val - these functions are marked
#[unstable], but will continue to exist in some form. Concerns have been
raised about their `_val` prefix.
Excluding the functions inherited from the cast module last week (with marked
stability levels), these functions received the following treatment.
* size_of - this method has become #[stable]
* nonzero_size_of/nonzero_size_of_val - these methods have been removed
* min_align_of - this method is now #[stable]
* pref_align_of - this method has been renamed without the
`pref_` prefix, and it is the "default alignment" now. This decision is in line
with what clang does (see url linked in comment on function). This function
is now #[stable].
* init - renamed to zeroed and marked #[stable]
* uninit - marked #[stable]
* move_val_init - renamed to overwrite and marked #[stable]
* {from,to}_{be,le}{16,32,64} - all functions marked #[stable]
* swap/replace/drop - marked #[stable]
* size_of_val/min_align_of_val/align_of_val - these functions are marked
#[unstable], but will continue to exist in some form. Concerns have been
raised about their `_val` prefix.
[breaking-change]
The #[phase(syntax,link)] attribute on `extern crate std` needs to be an
outer attribute so it can pretty-print properly.
Also add `#![no_std]` and `#[feature(phase)]` so compiling the
pretty-printed source will work.
This commit is part of the ongoing libstd facade efforts (cc #13851). The
compiler now recognizes some language items as "extern { fn foo(...); }" and
will automatically perform the following actions:
1. The foreign function has a pre-defined name.
2. The crate and downstream crates can only be built as rlibs until a crate
defines the lang item itself.
3. The actual lang item has a pre-defined name.
This is essentially nicer compiler support for the hokey
core-depends-on-std-failure scheme today, but it is implemented the same way.
The details are a little more hidden under the covers.
In addition to failure, this commit promotes the eh_personality and
rust_stack_exhausted functions to official lang items. The compiler can generate
calls to these functions, causing linkage errors if they are left undefined. The
checking for these items is not as precise as it could be. Crates compiling with
`-Z no-landing-pads` will not need the eh_personality lang item, and crates
compiling with no split stacks won't need the stack exhausted lang item. For
ease, however, these items are checked for presence in all final outputs of the
compiler.
It is quite easy to define dummy versions of the functions necessary:
#[lang = "stack_exhausted"]
extern fn stack_exhausted() { /* ... */ }
#[lang = "eh_personality"]
extern fn eh_personality() { /* ... */ }
cc #11922, rust_stack_exhausted is now a lang item
cc #13851, libcollections is blocked on eh_personality becoming weak
Rng.choose() is used so rarely that it doesn't necessitate having two
methods, especially since the failing, non-option variant also requires
Clone.
[breaking-change]
Consider PatEnums constructed with A(..) to be candidates for tuple
struct patterns, not just ones constructed with A(a,b,c). If these
patterns shouldn't be valid tuple struct patterns (as they're equivalent
to _), this needs to be caught before we get to trans.
Fixes#14308.
Make configure script respect (and save) values for `CC`, `CXX`, `CFLAGS` etc.
I mostly tried to remain backwards compatible with old invocations of
the `configure` script; if you do not want to use `CC` et al., you
should not have to; you can keep using `--enable-clang` and/or
`--enable-ccache`.
The overall intention is to capture the following precedences for
guessing the C compiler:
1. Value of `CC` at `make` invocation time.
2. Value of `CC` at `configure` invocation time.
3. Compiler inferred at configure invocation time (`gcc` or `clang`).
The strategy is to check (at `configure` time) if each of the
environment variables is set, and if so, save its value in a
corresponding `CFG_` variable (e.g. `CFG_CC`).
The `configure` script also does not attempt to infer the compiler if
`CC` is set; but if `--enable-clang` was passed, then it *does* still
attempt to validate that the clang version is compatible.
Then, in the makefiles, if `CC` is not set but `CFG_CC` is, then we
use the `CFG_CC` setting as `CC`.
Fix#13805.
Tweak region inference to ignore constraints like `'a <= 'static`, since they
have no value. This also ensures that we can handle some obscure cases of fn
subtyping with bound regions that we didn't used to handle correctly.
Fixes#13974.
Attempt to highlight the placement expression in a `box (expr) foo`
expression. Also treat GC as a keyword within the placement expression.
This doesn't work correctly for arbitrary expressions. Notably, this
makes no attempt at balancing delimiters. I believe handling that will
require rewriting the syntax rules to add a region for every pair of
delimiters. That may be a desirable thing to do in the end, because we
can then rewrite our indent rules based on the syntax and get rid of
cindent(), but for the time being, we'll just live with the limitation.
I mostly tried to remain backwards compatible with old invocations of
the `configure` script; if you do not want to use `CC` et al., you
should not have to; you can keep using `--enable-clang` and/or
`--enable-ccache`.
The overall intention is to capture the following precedences for
guessing the C compiler:
1. Value of `CC` at make invocation time.
2. Value of `CC` at configure invocation time.
3. Compiler inferred at configure invocation time (`gcc` or `clang`).
The strategy is to check (at `configure` time) if each of the
environment variables is set, and if so, save its value in a
corresponding `CFG_` variable (e.g. `CFG_CC`).
Then, in the makefiles, if `CC` is not set but `CFG_CC` is, then we
use the `CFG_CC` setting as `CC`.
Also, I fold the potential user-provided `CFLAGS` and `CXXFLAGS`
values into all of the per-platform `CFLAGS` and `CXXFLAGS` settings.
(This was opposed to adding `$(CFLAGS)` in an ad-hoc manner to various
parts of the mk files.)
Fix#13805.
----
Note that if you try to set the compiler to clang via the `CC` and
`CXX` environment variables, you will probably need to also set
`CXXFLAGS` to `--enable-libcpp` so that LLVM will be configured
properly.
----
Introduce CFG_USING_CLANG, which is distinguished from
CFG_ENABLE_CLANG because the former represents "we think we're using
clang, choose appropriate warning-control options" while the latter
represents "we asked configure (or the host required) that we attempt
to use clang, so check that we have an appropriate version of clang."
The main reason I added this is that I wanted to allow the user to
choose clang via setting the `CC` environment variable, but I did not
want that method of selection to get confused with the user passing
the `--enable-clang` option.
----
A digression: The `configure` script does not infer the compiler
setting if `CC` is set; but if `--enable-clang` was passed, then it
*does* still attempt to validate that the clang version is compatible.
Supporting this required revising `CLANG_VERSION` check to be robust
in face of user-provided `CC` value.
In particular, on Travis, the `CC` is set to `gcc` and so the natural
thing to do is to attempt to use `gcc` as the compiler, but Travis is
also passing `--enable-clang` to configure. So, what is the right
answer in the face of these contradictory requests?
One approach would be to have `--enable-clang` supersede the setting
for `CC` (and instead just call whatever we inferred for `CFG_CLANG`).
That sounds maximally inflexible to me (pnkfelix): a developer
requesting a `CC` value probably wants it respected, and should be
able to set it to something else; it is harder for that developer to
hack our configure script to change its inferred path to clang.
A second approach would be to blindly use the `CC` value but keep
going through the clang version check when `--enable-clang` is turned
on. But on Travis (a Linux host), the `gcc` invocation won't print a
clang version, so we would not get past the CLANG_VERSION check in
that context.
A third approach would be to never run the CLANG_VERSION check if `CC`
is explicitly set. That is not a terrible idea; but if the user uses
`CC` to pass in a path to some other version of clang that they want
to test, probably should still send that through the `CLANG_VERSION`
check.
So in the end I (pnkfelix) took a fourth approach: do the
CLANG_VERSION check if `CC` is unset *or* if `CC` is set to a string
ending with `clang`. This way setting `CC` to things like
`path/to/clang` or `ccache clang` will still go through the
CLANG_VERSION check, while setting `CC` to `gcc` or some unknown
compiler will skip the CLANG_VERSION check (regardless of whether the
user passed --enable-clang to `configure`).
----
Drive-by fixes:
* The call that sets `CFG_CLANG_VERSION` was quoting `"$CFG_CC"` in
its invocation, but that does not play nicely with someone who sets
`$CFG_CC` to e.g. `ccache clang`, since you do not want to intepret
that whole string as a command.
(On the other hand, a path with spaces might need the quoted
invocation. Not sure which one of these corner use-cases is more
important to support.)
* Fix chk_cc error message to point user at `gcc` not `cc`.
