Use proper span for tuple index parsed as float
Fix diagnostic suggestion from:
```rust
help: try parenthesizing the first index
| (1, (2, 3)).((1, (2, 3)).1).1;
```
to the correct:
```rust
help: try parenthesizing the first index
| ((1, (2, 3)).1).1;
```
Fix#41081.
```rust
error[E0072]: recursive type `X` has infinite size
--> file.rs:10:1
|
10 | struct X {
| ^^^^^^^^ recursive type has infinite size
|
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `X` representable
```
vs
```rust
error[E0072]: recursive type `X` has infinite size
--> file.rs:10:1
|
10 | struct X {
| _^ starting here...
11 | | x: X,
12 | | }
| |_^ ...ending here: recursive type has infinite size
|
= help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `X` representable
```
Point at only one char on `Span::next_point`
Avoid pointing at two chars so the diagnostic output doesn't display a
multiline span when starting beyond a line end.
Fix#41155.
Instead of
```rust
error: expected one of `(`, `const`, `default`, `extern`, `fn`, `type`, or `unsafe`, found `}`
--> <anon>:3:1
|
1 | impl S { pub
| _____________- starting here...
2 | |
| | ...ending here: expected one of 7 possible tokens here
3 | }
| ^ unexpected token
```
show
```rust
error: expected one of `(`, `const`, `default`, `extern`, `fn`, `type`, or `unsafe`, found `}`
--> <anon>:13:1
|
12 | pub
| - expected one of 7 possible tokens here
13 | }
| ^ unexpected token
```
-Z linker-flavor
(Please read the commit message first)
This PR is an alternative to rust-lang/rust#36120 (internal lld linker). The
main goal of this PR is to make it *possible* to use LLD as a linker to allow
out of tree experimentation. Now that LLD is going to be shipped with LLVM 4.0,
it should become easier to get a hold of LLD (hopefully, it will be packaged by
Linux distros soon).
Since LLD is a multiarch linker, it has the potential to make cross compilation
easier (less tools need to be installed). Supposedly, LLD is also faster than
the gold linker so LLD may improve build times where link times are significant
(e.g. 100% incremental compilation reuse).
The place where LLD shines is at linking Rust programs that don't depend on
system libraries. For example, here's how you would link a bare metal ARM
Cortex-M program:
```
$ xargo rustc --target thumbv7m-none-eabi -- -Z linker-flavor=ld -C linker=ld.lld -Z print-link-args
"ld.lld" \
"-L" \
"$XARGO_HOME/lib/rustlib/thumbv7m-none-eabi/lib" \
"$PWD/target/thumbv7m-none-eabi/debug/deps/app-de1f86df314ad68c.0.o" \
"-o" \
"$PWD/target/thumbv7m-none-eabi/debug/deps/app-de1f86df314ad68c" \
"--gc-sections" \
"-L" \
"$PWD/target/thumbv7m-none-eabi/debug/deps" \
"-L" \
"$PWD/target/debug/deps" \
"-L" \
"$XARGO_HOME/lib/rustlib/thumbv7m-none-eabi/lib" \
"-Bstatic" \
"-Bdynamic" \
"$XARGO_HOME/lib/rustlib/thumbv7m-none-eabi/lib/libcore-11670d2bd4951fa7.rlib"
$ file target/thumbv7m-none-eabi/debug/app
app: ELF 32-bit LSB executable, ARM, EABI5 version 1 (SYSV), statically linked, not stripped, with debug_info
```
This doesn't require installing the `arm-none-eabi-gcc` toolchain.
Even cooler (but I'm biased) is that you can link Rust programs that use
[`steed`] (`steed` is a `std` re-implementation free of C dependencies for Linux
systems) instead of `std` for a bunch of different architectures without having
to install a single cross toolchain.
[`steed`]: https://github.com/japaric/steed
```
$ xargo rustc --target aarch64-unknown-linux-steed --example hello --release -- -Z print-link-args
"ld.lld" \
"-L" \
"$XARGO_HOME/lib/rustlib/aarch64-unknown-linux-steed/lib" \
"$PWD/target/aarch64-unknown-linux-steed/release/examples/hello-80c130ad884c0f8f.0.o" \
"-o" \
"$PWD/target/aarch64-unknown-linux-steed/release/examples/hello-80c130ad884c0f8f" \
"--gc-sections" \
"-L" \
"$PWD/target/aarch64-unknown-linux-steed/release/deps" \
"-L" \
"$PWD/target/release/deps" \
"-L" \
"$XARGO_HOME/lib/rustlib/aarch64-unknown-linux-steed/lib" \
"-Bstatic" \
"-Bdynamic" \
"/tmp/rustc.lAybk9Ltx93Q/libcompiler_builtins-589aede02de78434.rlib"
$ file target/aarch64-unknown-linux-steed/release/examples/hello
hello: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, not stripped, with debug_info
```
All these targets (architectures) worked with LLD:
- [aarch64-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/aarch64-unknown-linux-steed.json)
- [arm-unknown-linux-steedeabi](https://github.com/japaric/steed/blob/lld/docker/arm-unknown-linux-steedeabi.json)
- [arm-unknown-linux-steedeabihf](https://github.com/japaric/steed/blob/lld/docker/arm-unknown-linux-steedeabihf.json)
- [armv7-unknown-linux-steedeabihf](https://github.com/japaric/steed/blob/lld/docker/armv7-unknown-linux-steedeabihf.json)
- [i686-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/i686-unknown-linux-steed.json)
- [mips-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/mips-unknown-linux-steed.json)
- [mipsel-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/mipsel-unknown-linux-steed.json)
- [powerpc-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/powerpc-unknown-linux-steed.json)
- [powerpc64-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/powerpc64-unknown-linux-steed.json)
- [x86_64-unknown-linux-steed](https://github.com/japaric/steed/blob/lld/docker/x86_64-unknown-linux-steed.json)
---
The case where lld is unergonomic is linking binaries that depend on system
libraries. Like "Hello, world" for `x86_64-unknown-linux-gnu`. Because you have
to pass as linker arguments: the path to the startup objects, the path to the
dynamic linker and the library search paths. And all those are system specific
so they can't be encoded in the target itself.
```
$ cargo \
rustc \
--release \
-- \
-C \
linker=ld.lld \
-Z \
linker-flavor=ld \
-C \
link-args='-dynamic-linker /lib64/ld-linux-x86-64.so.2 -L/usr/lib -L/usr/lib/gcc/x86_64-pc-linux-gnu/6.3.1 /usr/lib/Scrt1.o /usr/lib/crti.o /usr/lib/gcc/x86_64-pc-linux-gnu/6.3.1/crtbeginS.o /usr/lib/gcc/x86_64-pc-linux-gnu/6.3.1/crtendS.o /usr/lib/crtn.o'
```
---
Another case where `-Z linker-flavor` may come in handy is directly calling
Solaris' linker which is also a multiarch linker (or so I have heard). cc
@binarycrusader
cc @alexcrichton
Heads up: [breaking-change] due to changes in the target specification format.
Introduce `TyErr` independent from `TyInfer`
Add a `TyErr` type to represent unknown types in places where
parse errors have happened, while still able to build the AST.
Initially only used to represent incorrectly written fn arguments and
avoid "expected X parameters, found Y" errors when called with the
appropriate amount of parameters. We cannot use `TyInfer` for this as
`_` is not allowed as a valid argument type.
Example output:
```rust
error: expected one of `:` or `@`, found `,`
--> file.rs:12:9
|
12 | fn bar(x, y: usize) {}
| ^
error[E0061]: this function takes 2 parameters but 3 parameters were supplied
--> file.rs:19:9
|
12 | fn bar(x, y) {}
| --------------- defined here
...
19 | bar(1, 2, 3);
| ^^^^^^^ expected 2 parameters
```
Fix#34264.
#[used] attribute
(For an explanation of what this feature does, read the commit message)
I'd like to propose landing this as an experimental feature (experimental as in:
no clear stabilization path -- like `asm!`, `#[linkage]`) as it's low
maintenance (I think) and relevant to the "Usage in resource-constrained
environments" exploration area.
The main use case I see is running code before `main`. This could be used, for
instance, to cheaply initialize an allocator before `main` where the alternative
is to use `lazy_static` to initialize the allocator on its first use which it's
more expensive (atomics) and doesn't work on ARM Cortex-M0 microcontrollers (no
`AtomicUsize` on that platform)
Here's a `std` example of that:
``` rust
unsafe extern "C" fn before_main_1() {
println!("Hello");
}
unsafe extern "C" fn before_main_2() {
println!("World");
}
#[link_section = ".init_arary"]
#[used]
static INIT_ARRAY: [unsafe extern "C" fn(); 2] = [before_main_1, before_main_2];
fn main() {
println!("Goodbye");
}
```
```
$ rustc -C lto -C opt-level=3 before_main.rs
$ ./before_main
Hello
World
Goodbye
```
In general, this pattern could be used to let *dependencies* run code before
`main` (which sounds like it could go very wrong in some cases). There are
probably other use cases; I hope that the people I have cc-ed can comment on
those.
Note that I'm personally unsure if the above pattern is something we want to
promote / allow and that's why I'm proposing this feature as experimental. If
this leads to more footguns than benefits then we can just axe the feature.
cc @nikomatsakis ^ I know you have some thoughts on having a process for
experimental features though I'm fine with writing an RFC before landing this.
- `dead_code` lint will have to be updated to special case `#[used]` symbols.
- Should we extend `#[used]` to work on non-generic functions?
cc rust-lang/rfcs#1002
cc rust-lang/rfcs#1459
cc @dpc @JinShil
similar to GCC's __attribute((used))__. This attribute prevents LLVM from
optimizing away a non-exported symbol, within a compilation unit (object file),
when there are no references to it.
This is better explained with an example:
```
#[used]
static LIVE: i32 = 0;
static REFERENCED: i32 = 0;
static DEAD: i32 = 0;
fn internal() {}
pub fn exported() -> &'static i32 {
&REFERENCED
}
```
Without optimizations, LLVM pretty much preserves all the static variables and
functions within the compilation unit.
```
$ rustc --crate-type=lib --emit=obj symbols.rs && nm -C symbols.o
0000000000000000 t drop::h1be0f8f27a2ba94a
0000000000000000 r symbols::REFERENCED::hb3bdfd46050bc84c
0000000000000000 r symbols::DEAD::hc2ea8f9bd06f380b
0000000000000000 r symbols::LIVE::h0970cf9889edb56e
0000000000000000 T symbols::exported::h6f096c2b1fc292b2
0000000000000000 t symbols::internal::h0ac1aadbc1e3a494
```
With optimizations, LLVM will drop dead code. Here `internal` is dropped because
it's not a exported function/symbol (i.e. not `pub`lic). `DEAD` is dropped for
the same reason. `REFERENCED` is preserved, even though it's not exported,
because it's referenced by the `exported` function. Finally, `LIVE` survives
because of the `#[used]` attribute even though it's not exported or referenced.
```
$ rustc --crate-type=lib -C opt-level=3 --emit=obj symbols.rs && nm -C symbols.o
0000000000000000 r symbols::REFERENCED::hb3bdfd46050bc84c
0000000000000000 r symbols::LIVE::h0970cf9889edb56e
0000000000000000 T symbols::exported::h6f096c2b1fc292b2
```
Note that the linker knows nothing about `#[used]` and will drop `LIVE`
because no other object references to it.
```
$ echo 'fn main() {}' >> symbols.rs
$ rustc symbols.rs && nm -C symbols | grep LIVE
```
At this time, `#[used]` only works on `static` variables.
Fix diagnostic suggestion from:
```rust
help: try parenthesizing the first index
| (1, (2, 3)).((1, (2, 3)).1).1;
```
to the correct:
```rust
help: try parenthesizing the first index
| ((1, (2, 3)).1).1;
```
rustc: Stabilize the `#![windows_subsystem]` attribute
This commit stabilizes the `#![windows_subsystem]` attribute which is a
conservative exposure of the `/SUBSYSTEM` linker flag on Widnows platforms. This
is useful for creating applications as well as console programs.
Closes#37499
Add a `TyErr` type to represent unknown types in places where
parse errors have happened, while still able to build the AST.
Initially only used to represent incorrectly written fn arguments and
avoid "expected X parameters, found Y" errors when called with the
appropriate amount of parameters. We cannot use `TyInfer` for this as
`_` is not allowed as a valid argument type.
Example output:
```rust
error: expected one of `:` or `@`, found `,`
--> file.rs:12:9
|
12 | fn bar(x, y: usize) {}
| ^
error[E0061]: this function takes 2 parameters but 3 parameters were supplied
--> file.rs:19:9
|
12 | fn bar(x, y) {}
| --------------- defined here
...
19 | bar(1, 2, 3);
| ^^^^^^^ expected 2 parameters
```
This commit stabilizes the `#![windows_subsystem]` attribute which is a
conservative exposure of the `/SUBSYSTEM` linker flag on Widnows platforms. This
is useful for creating applications as well as console programs.
Closes#37499
`match { }` now (correctly?) indicates divergence, which results in more
unreachable warnings. We also avoid fallback to `!` if there is just one
arm (see new test: `match-unresolved-one-arm.rs`).
Remove internal liblog
This commit deletes the internal liblog in favor of the implementation that
lives on crates.io. Similarly it's also setting a convention for adding crates
to the compiler. The main restriction right now is that we want compiler
implementation details to be unreachable from normal Rust code (e.g. requires a
feature), and by default everything in the sysroot is reachable via `extern
crate`.
The proposal here is to require that crates pulled in have these lines in their
`src/lib.rs`:
#![cfg_attr(rustbuild, feature(staged_api, rustc_private))]
#![cfg_attr(rustbuild, unstable(feature = "rustc_private", issue = "27812"))]
This'll mean that by default they're not using these attributes but when
compiled as part of the compiler they do a few things:
* Mark themselves as entirely unstable via the `staged_api` feature and the
`#![unstable]` attribute.
* Allow usage of other unstable crates via `feature(rustc_private)` which is
required if the crate relies on any other crates to compile (other than std).
* Point at where the token was expected instead of the last token
successfuly parsed.
* Only show `unexpected token` if the next char and the unexpected token
don't have the same span.
* Change some cfail and pfail tests to ui test.
* Don't show all possible tokens in span label if they are more than 6.
```rust
error: expected one of `.`, `;`, `?`, `}`, or an operator, found `)`
--> $DIR/token-error-correct-3.rs:29:9
|
25 | foo()
| - expected one of `.`, `;`, `?`, `}`, or an operator after this
...
29 | } else {
| ^ unexpected token
```
```rust
struct S;
impl S {
pub hello_method(&self) {
println!("Hello");
}
}
fn main() { S.hello_method(); }
```
```rust
error: can't qualify macro invocation with `pub`
--> file.rs:3:4
|
3 | pub hello_method(&self) {
| ^^^- - expected `!` here for a macro invocation
| |
| did you mean to write `fn` here for a method declaration?
|
= help: try adjusting the macro to put `pub` inside the invocation
```
This commit deletes the internal liblog in favor of the implementation that
lives on crates.io. Similarly it's also setting a convention for adding crates
to the compiler. The main restriction right now is that we want compiler
implementation details to be unreachable from normal Rust code (e.g. requires a
feature), and by default everything in the sysroot is reachable via `extern
crate`.
The proposal here is to require that crates pulled in have these lines in their
`src/lib.rs`:
#![cfg_attr(rustbuild, feature(staged_api, rustc_private))]
#![cfg_attr(rustbuild, unstable(feature = "rustc_private", issue = "27812"))]
This'll mean that by default they're not using these attributes but when
compiled as part of the compiler they do a few things:
* Mark themselves as entirely unstable via the `staged_api` feature and the
`#![unstable]` attribute.
* Allow usage of other unstable crates via `feature(rustc_private)` which is
required if the crate relies on any other crates to compile (other than std).
Add diagnostic for incorrect `pub (restriction)`
Given the following statement
```rust
pub (a) fn afn() {}
```
Provide the following diagnostic:
```rust
error: incorrect restriction in `pub`
--> file.rs:15:1
|
15 | pub (a) fn afn() {}
| ^^^
|
= help: some valid visibility restrictions are:
`pub(crate)`: visible only on the current crate
`pub(super)`: visible only in the current module's parent
`pub(in path::to::module)`: visible only on the specified path
help: to make this visible only to module `a`, add `in` before the path:
| pub (in a) fn afn() {}
```
Follow up to #40340, fix#40599, cc #32409.
Given the following statement
```rust
pub (a) fn afn() {}
```
Provide the following diagnostic:
```rust
error: incorrect restriction in `pub`
--> file.rs:15:1
|
15 | pub (a) fn afn() {}
| ^^^^^^^
|
= help: some valid visibility restrictions are:
`pub(crate)`: visible only on the current crate
`pub(super)`: visible only in the current module's parent
`pub(in path::to::module)`: visible only on the specified path
help: to make this visible only to module `a`, add `in` before the path:
| pub (in a) fn afn() {}
```
Remove cruft from old `pub(path)` syntax.
HirId has a more stable representation than NodeId, meaning that
modifications to one item don't influence (part of) the IDs within
other items. The other part is a DefIndex for which there already
is a way of stable hashing and persistence.
This commit introduces the HirId type and generates a HirId for
every NodeId during HIR lowering, but the resulting values are
not yet used anywhere, except in consistency checks.
