Update the Fuchsia linker defaults
This updates the linker defaults aligning them with Clang. Specifically,
we use 4K pages on all platforms, we always use BIND_NOW, we prefer all
loadable segments be separate and page aligned, and we support RELR
relocations.
rustdoc: remove calls to `local_def_id_from_node_id`
rustdoc calls `local_def_id_from_node_id(CRATE_NODE_ID)` when it can just creates a top level `DefId` using `DefId::local(CRATE_DEF_INDEX)`.
cc #50928
r? @petrochenkov
Fix is_char_boundary documentation
Given the "start _and/or end_" wording in the original, the way I understood it was that the `str::is_char_boundary` method would also return `true` for the last byte in a UTF-8 code point sequence. (Which would have meant that for a string consisting of nothing but 1 and 2 byte UTF-8 code point sequences, it would return nothing but `true`.)
In practice the method returns `true` only for the starting byte of each sequence and the end of the string: [Playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=e9f5fc4d6bf2f1bf57a75f3c9a180770)
I was also somewhat tempted to remove the _The start and end of the string are considered to be boundaries_, since that's implied by the first sentence, but I decided to avoid bikeshedding over it and left it as it was since it's not wrong in relation to how the method behaves.
miri validation: clarify valid values of 'char'
The old text said "expected a valid unicode codepoint", which is not actually correct -- it has to be a scalar value (which is a code point that is not part of a surrogate pair).
rustc_lexer: Optimize shebang detection slightly
Sorry, I just couldn't resist.
It shouldn't make any difference in practice.
Also, documented a previously unnoticed case with doc comments treated as regular comments during shebang detection.
Fix missing parentheses Fn notation error
Fixes #72611
Well, fixes the error output, I think E0658 is the right error to throw in this case so I didn't change that
Add -Z profile-emit=<path> for Gcov gcda output.
Adds a -Z flag to control the file path that the Gcov gcda output is
written to during runtime. This flag expects a path and filename, e.g.
-Z profile-emit=gcov/out/lib.gcda.
This works similar to GCC/Clang's -fprofile-dir flag which allows
control over the output path for gcda coverage files.
Allow types (with lifetimes/generics) in impl_lint_pass
cc https://github.com/rust-lang/rust-clippy/pull/5279#discussion_r430790267
This allows to implement `LintPass` for types with lifetimes and/or generics. The only thing, I'm not sure of is the `LintPass::name` function, which now includes the lifetime(s) (which will be `'_` most of the time) in the name returned for the lint pass, if it exists. But I don't think that this should be a problem, since the `LintPass::name` is never used for output for the user (?).
Improve inline asm error diagnostics
Previously we were just using the raw LLVM error output (with line, caret, etc) as the diagnostic message, which ends up looking rather out of place with our existing diagnostics.
The new diagnostics properly format the diagnostics and also take advantage of LLVM's per-line `srcloc` attribute to map an error in inline assembly directly to the relevant line of source code.
Incidentally also fixes#71639 by disabling `srcloc` metadata during LTO builds since we don't know what crate it might have come from. We can only resolve `srcloc`s from the currently crate since it indexes into the source map for the current crate.
Fixes#72664Fixes#71639
r? @petrochenkov
### Old style
```rust
#![feature(llvm_asm)]
fn main() {
unsafe {
let _x: i32;
llvm_asm!(
"mov $0, $1
invalid_instruction $0, $1
mov $0, $1"
: "=&r" (_x)
: "r" (0)
:: "intel"
);
}
}
```
```
error: <inline asm>:3:14: error: invalid instruction mnemonic 'invalid_instruction'
invalid_instruction ecx, eax
^~~~~~~~~~~~~~~~~~~
--> src/main.rs:6:9
|
6 | / llvm_asm!(
7 | | "mov $0, $1
8 | | invalid_instruction $0, $1
9 | | mov $0, $1"
... |
12 | | :: "intel"
13 | | );
| |__________^
```
### New style
```rust
#![feature(asm)]
fn main() {
unsafe {
asm!(
"mov {0}, {1}
invalid_instruction {0}, {1}
mov {0}, {1}",
out(reg) _,
in(reg) 0i64,
);
}
}
```
```
error: invalid instruction mnemonic 'invalid_instruction'
--> test.rs:7:14
|
7 | invalid_instruction {0}, {1}
| ^
|
note: instantiated into assembly here
--> <inline asm>:3:14
|
3 | invalid_instruction rax, rcx
| ^^^^^^^^^^^^^^^^^^^
```
Account for missing lifetime in opaque and trait object return types
When encountering an opaque closure return type that needs to bound a
lifetime to the function's arguments, including borrows and type params,
provide appropriate suggestions that lead to working code.
Get the user from
```rust
fn foo<G, T>(g: G, dest: &mut T) -> impl FnOnce()
where
G: Get<T>
{
move || {
*dest = g.get();
}
}
```
to
```rust
fn foo<'a, G: 'a, T>(g: G, dest: &'a mut T) -> impl FnOnce() +'a
where
G: Get<T>
{
move || {
*dest = g.get();
}
}
```
We have been seeing some very inefficient code that went away when using
`-Cforce-frame-pointers=no`. For instance `core::ptr::drop_in_place` at
`-Oz` was compiled into a function which consisted entirely of saving
registers to the stack, then using the frame pointer to restore the same
registers (without any instructions between the prolog and epilog).
The RISC-V LLVM backend supports frame pointer elimination, so it makes
sense to allow this to happen when using Rust. It's not clear to me that
frame pointers have ever been required in the general case.
In rust-lang/rust#61675 it was pointed out that this made reassembling
stack traces easier, which is true, but there is a code generation
option for forcing frame pointers, and I feel the default should not be
to require frame pointers, given it demonstrably makes code size worse
(around 10% in some embedded applications).
The kinds of targets mentioned in rust-lang/rust#61675 are popular, but
should not dictate that code generation should be worse for all RISC-V
targets, especially as there is a way to use CFI information to
reconstruct the stack when the frame pointer is eliminated. It is also
a misconception that `fp` is always used for the frame pointer. `fp` is
an ABI name for `x8` (aka `s0`), and if no frame pointer is required,
`x8` may be used for other callee-saved values.
This commit does ensure that the standard library is built with unwind
tables, so that users do not need to rebuild the standard library in
order to get a backtrace that includes standard library calls (which is
the original reason for forcing frame pointers).
When encountering an opaque closure return type that needs to bound a
lifetime to the function's arguments, including borrows and type params,
provide appropriate suggestions that lead to working code.
Get the user from
```rust
fn foo<G, T>(g: G, dest: &mut T) -> impl FnOnce()
where
G: Get<T>
{
move || {
*dest = g.get();
}
}
```
to
```rust
fn foo<'a, G: 'a, T>(g: G, dest: &'a mut T) -> impl FnOnce() +'a
where
G: Get<T>
{
move || {
*dest = g.get();
}
}
```
