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Auto merge of #58415 - Centril:rollup, r=Centril
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Rollup of 12 pull requests

Successful merges:

 - #57693 (Doc rewording)
 - #57815 (Speed up the fast path for assert_eq! and assert_ne!)
 - #58034 (Stabilize the time_checked_add feature)
 - #58057 (Stabilize linker-plugin based LTO (aka cross-language LTO))
 - #58137 (Cleanup: rename node_id_to_type(_opt))
 - #58166 (allow shorthand syntax for deprecation reason)
 - #58200 (fix str mutating through a ptr derived from &self)
 - #58273 (Rename rustc_errors dependency in rust 2018 crates)
 - #58289 (impl iter() for dyn Error)
 - #58387 (Disallow `auto` trait alias syntax)
 - #58404 (use Ubuntu keyserver for CloudABI ports)
 - #58405 (Remove some dead code from libcore)

Failed merges:

r? @ghost
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bors committed Feb 13, 2019
2 parents 0f949c2 + 6562c28 commit 827a141
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9 changes: 4 additions & 5 deletions src/ci/docker/dist-various-2/build-cloudabi-toolchain.sh
Original file line number Diff line number Diff line change
Expand Up @@ -32,9 +32,8 @@ ln -s ../lib/llvm-5.0/bin/lld /usr/bin/${target}-ld
ln -s ../../${target} /usr/lib/llvm-5.0/${target}

# Install the C++ runtime libraries from CloudABI Ports.
echo deb https://nuxi.nl/distfiles/cloudabi-ports/debian/ cloudabi cloudabi > \
/etc/apt/sources.list.d/cloudabi.list
curl 'https://pgp.mit.edu/pks/lookup?op=get&search=0x0DA51B8531344B15' | \
apt-key add -
apt-key adv --batch --yes --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 0DA51B8531344B15
add-apt-repository -y 'deb https://nuxi.nl/distfiles/cloudabi-ports/debian/ cloudabi cloudabi'

apt-get update
apt-get install -y $(echo ${target} | sed -e s/_/-/g)-cxx-runtime
apt-get install -y "${target//_/-}-cxx-runtime"
3 changes: 2 additions & 1 deletion src/doc/rustc/src/SUMMARY.md
Original file line number Diff line number Diff line change
Expand Up @@ -13,4 +13,5 @@
- [Targets](targets/index.md)
- [Built-in Targets](targets/built-in.md)
- [Custom Targets](targets/custom.md)
- [Contributing to `rustc`](contributing.md)
- [Linker-plugin based LTO](linker-plugin-lto.md)
- [Contributing to `rustc`](contributing.md)
108 changes: 108 additions & 0 deletions src/doc/rustc/src/linker-plugin-lto.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,108 @@
# Linker-plugin-LTO

The `-C linker-plugin-lto` flag allows for deferring the LTO optimization
to the actual linking step, which in turn allows for performing
interprocedural optimizations across programming language boundaries if
all the object files being linked were created by LLVM based toolchains.
The prime example here would be linking Rust code together with
Clang-compiled C/C++ code.

## Usage

There are two main cases how linker plugin based LTO can be used:

- compiling a Rust `staticlib` that is used as a C ABI dependency
- compiling a Rust binary where `rustc` invokes the linker

In both cases the Rust code has to be compiled with `-C linker-plugin-lto` and
the C/C++ code with `-flto` or `-flto=thin` so that object files are emitted
as LLVM bitcode.

### Rust `staticlib` as dependency in C/C++ program

In this case the Rust compiler just has to make sure that the object files in
the `staticlib` are in the right format. For linking, a linker with the
LLVM plugin must be used (e.g. LLD).

Using `rustc` directly:

```bash
# Compile the Rust staticlib
rustc --crate-type=staticlib -Clinker-plugin-lto -Copt-level=2 ./lib.rs
# Compile the C code with `-flto=thin`
clang -c -O2 -flto=thin -o main.o ./main.c
# Link everything, making sure that we use an appropriate linker
clang -flto=thin -fuse-ld=lld -L . -l"name-of-your-rust-lib" -o main -O2 ./cmain.o
```

Using `cargo`:

```bash
# Compile the Rust staticlib
RUSTFLAGS="-Clinker-plugin-lto" cargo build --release
# Compile the C code with `-flto=thin`
clang -c -O2 -flto=thin -o main.o ./main.c
# Link everything, making sure that we use an appropriate linker
clang -flto=thin -fuse-ld=lld -L . -l"name-of-your-rust-lib" -o main -O2 ./cmain.o
```

### C/C++ code as a dependency in Rust

In this case the linker will be invoked by `rustc`. We again have to make sure
that an appropriate linker is used.

Using `rustc` directly:

```bash
# Compile C code with `-flto`
clang ./clib.c -flto=thin -c -o ./clib.o -O2
# Create a static library from the C code
ar crus ./libxyz.a ./clib.o

# Invoke `rustc` with the additional arguments
rustc -Clinker-plugin-lto -L. -Copt-level=2 -Clinker=clang -Clink-arg=-fuse-ld=lld ./main.rs
```

Using `cargo` directly:

```bash
# Compile C code with `-flto`
clang ./clib.c -flto=thin -c -o ./clib.o -O2
# Create a static library from the C code
ar crus ./libxyz.a ./clib.o

# Set the linking arguments via RUSTFLAGS
RUSTFLAGS="-Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld" cargo build --release
```

### Explicitly specifying the linker plugin to be used by `rustc`

If one wants to use a linker other than LLD, the LLVM linker plugin has to be
specified explicitly. Otherwise the linker cannot read the object files. The
path to the plugin is passed as an argument to the `-Clinker-plugin-lto`
option:

```bash
rustc -Clinker-plugin-lto="/path/to/LLVMgold.so" -L. -Copt-level=2 ./main.rs
```


## Toolchain Compatibility

In order for this kind of LTO to work, the LLVM linker plugin must be able to
handle the LLVM bitcode produced by both `rustc` and `clang`.

Best results are achieved by using a `rustc` and `clang` that are based on the
exact same version of LLVM. One can use `rustc -vV` in order to view the LLVM
used by a given `rustc` version. Note that the version number given
here is only an approximation as Rust sometimes uses unstable revisions of
LLVM. However, the approximation is usually reliable.

The following table shows known good combinations of toolchain versions.

| | Clang 7 | Clang 8 |
|-----------|-----------|-----------|
| Rust 1.34 |||
| Rust 1.35 || ✓(?) |

Note that the compatibility policy for this feature might change in the future.
14 changes: 0 additions & 14 deletions src/libcore/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -227,20 +227,6 @@ mod unit;
// `core_arch` depends on libcore, but the contents of this module are
// set up in such a way that directly pulling it here works such that the
// crate uses the this crate as its libcore.
#[allow(unused_macros)]
macro_rules! test_v16 { ($item:item) => {}; }
#[allow(unused_macros)]
macro_rules! test_v32 { ($item:item) => {}; }
#[allow(unused_macros)]
macro_rules! test_v64 { ($item:item) => {}; }
#[allow(unused_macros)]
macro_rules! test_v128 { ($item:item) => {}; }
#[allow(unused_macros)]
macro_rules! test_v256 { ($item:item) => {}; }
#[allow(unused_macros)]
macro_rules! test_v512 { ($item:item) => {}; }
#[allow(unused_macros)]
macro_rules! vector_impl { ($([$f:ident, $($args:tt)*]),*) => { $($f!($($args)*);)* } }
#[path = "../stdsimd/crates/core_arch/src/mod.rs"]
#[allow(missing_docs, missing_debug_implementations, dead_code, unused_imports)]
#[unstable(feature = "stdsimd", issue = "48556")]
Expand Down
20 changes: 16 additions & 4 deletions src/libcore/macros.rs
Original file line number Diff line number Diff line change
Expand Up @@ -46,9 +46,12 @@ macro_rules! assert_eq {
match (&$left, &$right) {
(left_val, right_val) => {
if !(*left_val == *right_val) {
// The reborrows below are intentional. Without them, the stack slot for the
// borrow is initialized even before the values are compared, leading to a
// noticeable slow down.
panic!(r#"assertion failed: `(left == right)`
left: `{:?}`,
right: `{:?}`"#, left_val, right_val)
right: `{:?}`"#, &*left_val, &*right_val)
}
}
}
Expand All @@ -60,9 +63,12 @@ macro_rules! assert_eq {
match (&($left), &($right)) {
(left_val, right_val) => {
if !(*left_val == *right_val) {
// The reborrows below are intentional. Without them, the stack slot for the
// borrow is initialized even before the values are compared, leading to a
// noticeable slow down.
panic!(r#"assertion failed: `(left == right)`
left: `{:?}`,
right: `{:?}`: {}"#, left_val, right_val,
right: `{:?}`: {}"#, &*left_val, &*right_val,
format_args!($($arg)+))
}
}
Expand Down Expand Up @@ -97,9 +103,12 @@ macro_rules! assert_ne {
match (&$left, &$right) {
(left_val, right_val) => {
if *left_val == *right_val {
// The reborrows below are intentional. Without them, the stack slot for the
// borrow is initialized even before the values are compared, leading to a
// noticeable slow down.
panic!(r#"assertion failed: `(left != right)`
left: `{:?}`,
right: `{:?}`"#, left_val, right_val)
right: `{:?}`"#, &*left_val, &*right_val)
}
}
}
Expand All @@ -111,9 +120,12 @@ macro_rules! assert_ne {
match (&($left), &($right)) {
(left_val, right_val) => {
if *left_val == *right_val {
// The reborrows below are intentional. Without them, the stack slot for the
// borrow is initialized even before the values are compared, leading to a
// noticeable slow down.
panic!(r#"assertion failed: `(left != right)`
left: `{:?}`,
right: `{:?}`: {}"#, left_val, right_val,
right: `{:?}`: {}"#, &*left_val, &*right_val,
format_args!($($arg)+))
}
}
Expand Down
30 changes: 23 additions & 7 deletions src/libcore/str/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -1741,9 +1741,9 @@ mod traits {
}
#[inline]
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
let ptr = slice.as_ptr().add(self.start);
let ptr = slice.as_mut_ptr().add(self.start);
let len = self.end - self.start;
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, len))
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, len))
}
#[inline]
fn index(self, slice: &str) -> &Self::Output {
Expand Down Expand Up @@ -1805,8 +1805,8 @@ mod traits {
}
#[inline]
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
let ptr = slice.as_ptr();
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, self.end))
let ptr = slice.as_mut_ptr();
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, self.end))
}
#[inline]
fn index(self, slice: &str) -> &Self::Output {
Expand Down Expand Up @@ -1867,9 +1867,9 @@ mod traits {
}
#[inline]
unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output {
let ptr = slice.as_ptr().add(self.start);
let ptr = slice.as_mut_ptr().add(self.start);
let len = slice.len() - self.start;
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr as *mut u8, len))
super::from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, len))
}
#[inline]
fn index(self, slice: &str) -> &Self::Output {
Expand Down Expand Up @@ -2197,6 +2197,22 @@ impl str {
self as *const str as *const u8
}

/// Converts a mutable string slice to a raw pointer.
///
/// As string slices are a slice of bytes, the raw pointer points to a
/// [`u8`]. This pointer will be pointing to the first byte of the string
/// slice.
///
/// It is your responsibility to make sure that the string slice only gets
/// modified in a way that it remains valid UTF-8.
///
/// [`u8`]: primitive.u8.html
#[unstable(feature = "str_as_mut_ptr", issue = "58215")]
#[inline]
pub fn as_mut_ptr(&mut self) -> *mut u8 {
self as *mut str as *mut u8
}

/// Returns a subslice of `str`.
///
/// This is the non-panicking alternative to indexing the `str`. Returns
Expand Down Expand Up @@ -2484,7 +2500,7 @@ impl str {
// is_char_boundary checks that the index is in [0, .len()]
if self.is_char_boundary(mid) {
let len = self.len();
let ptr = self.as_ptr() as *mut u8;
let ptr = self.as_mut_ptr();
unsafe {
(from_utf8_unchecked_mut(slice::from_raw_parts_mut(ptr, mid)),
from_utf8_unchecked_mut(slice::from_raw_parts_mut(
Expand Down
2 changes: 1 addition & 1 deletion src/librustc/Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@ rustc-rayon-core = "0.1.1"
rustc_apfloat = { path = "../librustc_apfloat" }
rustc_target = { path = "../librustc_target" }
rustc_data_structures = { path = "../librustc_data_structures" }
rustc_errors = { path = "../librustc_errors" }
errors = { path = "../librustc_errors", package = "rustc_errors" }
serialize = { path = "../libserialize" }
syntax = { path = "../libsyntax" }
syntax_pos = { path = "../libsyntax_pos" }
Expand Down
2 changes: 1 addition & 1 deletion src/librustc/dep_graph/graph.rs
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use crate::errors::{Diagnostic, DiagnosticBuilder};
use errors::{Diagnostic, DiagnosticBuilder};
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::indexed_vec::{Idx, IndexVec};
Expand Down
10 changes: 5 additions & 5 deletions src/librustc/hir/lowering.rs
Original file line number Diff line number Diff line change
Expand Up @@ -31,7 +31,6 @@
//! in the HIR, especially for multiple identifiers.

use crate::dep_graph::DepGraph;
use crate::errors::Applicability;
use crate::hir::{self, ParamName};
use crate::hir::HirVec;
use crate::hir::map::{DefKey, DefPathData, Definitions};
Expand All @@ -41,14 +40,15 @@ use crate::hir::GenericArg;
use crate::lint::builtin::{self, PARENTHESIZED_PARAMS_IN_TYPES_AND_MODULES,
ELIDED_LIFETIMES_IN_PATHS};
use crate::middle::cstore::CrateStore;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::indexed_vec::IndexVec;
use rustc_data_structures::thin_vec::ThinVec;
use rustc_data_structures::sync::Lrc;
use crate::session::Session;
use crate::session::config::nightly_options;
use crate::util::common::FN_OUTPUT_NAME;
use crate::util::nodemap::{DefIdMap, NodeMap};
use errors::Applicability;
use rustc_data_structures::fx::FxHashSet;
use rustc_data_structures::indexed_vec::IndexVec;
use rustc_data_structures::thin_vec::ThinVec;
use rustc_data_structures::sync::Lrc;

use std::collections::{BTreeSet, BTreeMap};
use std::fmt::Debug;
Expand Down
2 changes: 1 addition & 1 deletion src/librustc/hir/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -10,12 +10,12 @@ pub use self::PrimTy::*;
pub use self::UnOp::*;
pub use self::UnsafeSource::*;

use crate::errors::FatalError;
use crate::hir::def::Def;
use crate::hir::def_id::{DefId, DefIndex, LocalDefId, CRATE_DEF_INDEX};
use crate::util::nodemap::{NodeMap, FxHashSet};
use crate::mir::mono::Linkage;

use errors::FatalError;
use syntax_pos::{Span, DUMMY_SP, symbol::InternedString};
use syntax::source_map::Spanned;
use rustc_target::spec::abi::Abi;
Expand Down
6 changes: 3 additions & 3 deletions src/librustc/infer/error_reporting/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -50,16 +50,16 @@ use super::region_constraints::GenericKind;
use super::{InferCtxt, RegionVariableOrigin, SubregionOrigin, TypeTrace, ValuePairs};
use crate::infer::{self, SuppressRegionErrors};

use crate::errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString};
use crate::hir;
use crate::hir::def_id::DefId;
use crate::hir::Node;
use crate::middle::region;
use std::{cmp, fmt};
use syntax_pos::{Pos, Span};
use crate::traits::{ObligationCause, ObligationCauseCode};
use crate::ty::error::TypeError;
use crate::ty::{self, subst::Subst, Region, Ty, TyCtxt, TyKind, TypeFoldable};
use errors::{Applicability, DiagnosticBuilder, DiagnosticStyledString};
use std::{cmp, fmt};
use syntax_pos::{Pos, Span};

mod note;

Expand Down
6 changes: 3 additions & 3 deletions src/librustc/infer/error_reporting/need_type_info.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use crate::infer::type_variable::TypeVariableOrigin;
use crate::ty::{self, Ty, Infer, TyVar};
use syntax::source_map::CompilerDesugaringKind;
use syntax_pos::Span;
use crate::errors::DiagnosticBuilder;
use errors::DiagnosticBuilder;

struct FindLocalByTypeVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
Expand All @@ -16,9 +16,9 @@ struct FindLocalByTypeVisitor<'a, 'gcx: 'a + 'tcx, 'tcx: 'a> {
}

impl<'a, 'gcx, 'tcx> FindLocalByTypeVisitor<'a, 'gcx, 'tcx> {
fn node_matches_type(&mut self, node_id: HirId) -> bool {
fn node_matches_type(&mut self, hir_id: HirId) -> bool {
let ty_opt = self.infcx.in_progress_tables.and_then(|tables| {
tables.borrow().node_id_to_type_opt(node_id)
tables.borrow().node_type_opt(hir_id)
});
match ty_opt {
Some(ty) => {
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@
use crate::infer::error_reporting::nice_region_error::NiceRegionError;
use crate::ty;
use crate::util::common::ErrorReported;
use crate::errors::Applicability;
use errors::Applicability;

impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
/// When given a `ConcreteFailure` for a function with arguments containing a named region and
Expand Down
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use crate::errors::DiagnosticBuilder;
use errors::DiagnosticBuilder;
use crate::hir::def_id::DefId;
use crate::infer::error_reporting::nice_region_error::NiceRegionError;
use crate::infer::lexical_region_resolve::RegionResolutionError;
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@ use crate::infer::error_reporting::nice_region_error::NiceRegionError;
use crate::infer::lexical_region_resolve::RegionResolutionError;
use crate::ty::{BoundRegion, FreeRegion, RegionKind};
use crate::util::common::ErrorReported;
use crate::errors::Applicability;
use errors::Applicability;

impl<'a, 'gcx, 'tcx> NiceRegionError<'a, 'gcx, 'tcx> {
/// Print the error message for lifetime errors when the return type is a static impl Trait.
Expand Down
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