cleanup more iterator usages (and other things)
* Improve weird formatting by moving comment inside else-code block.
* Use .any(x) instead of .find(x).is_some() on iterators.
* Use .nth(x) instead of .skip(x).next() on iterators.
* Simplify conditions like x + 1 <= y to x < y
* Use let instead of match to get value of enum with single variant.
Previously, the code responsible for handling the cycles between crates
introduces through weak lang items, would keep a set of missing language
items:
* extending it with items missing from the current crate,
* removing items provided by the current crate,
* grouping the crates when the set changed from non-empty back to empty.
This could produce incorrect results, if a lang item was missing from a
crate that comes after the crate that provides it (in the loop iteration
order). In that case the grouping would not take place.
The changes here address this specific failure scenario by keeping track
of two separate sets of crates. Those that are required to link successfully,
and those that are available for linking.
Verified using test case from 69368.
Support new LLVM pass manager
Add support for the new LLVM pass manager behind a `-Z new-llvm-pass-manager=on` option. Both the pre-link optimization and LTO pipelines use the new pass manager. There's some bits that are not supported yet:
* `-C passes`. NewPM requires an entirely different way of specifying custom pass pipelines. We should probably expose that functionality, but it doesn't directly map to what `-C passes` does.
* NewPM has no support for custom inline parameters right now. We'd have to add upstream support for that first.
* NewPM does not support PGO at O0 in LLVM 9 (which is why those tests fail with NewPM enabled). This is supported in LLVM 10.
* NewPM does not support MergeFunctions in LLVM 9. I've landed this upstream just before the cut, so we'll be able to re-enable that with LLVM 10.
Closes#64289.
r? @ghost
windows-gnu: prefer system crt libraries if they are available
The origin of the issue is the fact Rust ships mingw-w64 libraries but no headers and prefers own libraries over the system ones.
This leads to situation when headers aren't compatible with libraries (mingw-w64 doesn't provide any forward compatibility and AFAIK backwards compatibility is guaranteed only within major release series).
It's easier to understand how this PR works when looking at the linker invocation before and with this PR: https://www.diffchecker.com/GEuYFmzo
It adds system libraries path before Rust libraries so the linker will prefer them.
It has potential issue when system has files with the same names as Rust but that could be avoided by moving Rust shipped mingw-w64 libraries from `lib/rustlib/x86_64-pc-windows-gnu/lib` to say `lib/rustlib/x86_64-pc-windows-gnu/lib/mingw`. Then adding linker paths in this order: Rust libraries, system libraries, Rust shipped mingw-w64 libraries.
Fixes#47048Fixes#49078Fixes#53454Fixes#60912
Slimmer syntax
High-level summary of changes:
- The `syntax::node_count` pass is moved into `rustc_ast_passes`. This works towards improving #65031 by making compiling `syntax` go faster.
- The `syntax::{GLOBALS, with_globals, ..}` business is consolidated into `syntax::attr` for cleaner code and future possible improvements.
- The pretty printer loses its dependency on `ParseSess`, opting to use `SourceMap` & friends directly instead.
- Some drive by cleanup of `syntax::attr::HasAttr` happens.
- Builtin attribute logic (`syntax::attr::builtin`) + `syntax::attr::allow_internal_unstable` is moved into a new `rustc_attr` crate. More logic from `syntax::attr` should be moved into that crate over time. This also means that `syntax` loses all mentions of `ParseSess`, which enables the next point.
- The pretty printer `syntax::print` is moved into a new crate `rustc_ast_pretty`.
- `rustc_session::node_id` is moved back as `syntax::node_id`. As a result, `syntax` gets to drop dependencies on `rustc_session` (and implicitly `rustc_target`), `rustc_error_codes`, and `rustc_errors`. Moreover `rustc_hir` gets to drop its dependency on `rustc_session` as well. At this point, these crates are mostly "pure data crates", which is approaching a desirable end state.
- We should consider renaming `syntax` to `rustc_ast` now.
This patch enables rustc to emit the required LLVM module flags to enable Control Flow Guard metadata (cfguard=1) or metadata and checks (cfguard=2). The LLVM module flags are ignored on unsupported targets and operating systems.
Also share drop-glue when compiling with -Zshare-generics (i.e. at opt-level=0)
This PR adds drop-glue to the set of monomorphizations that can be shared across crates via `-Zshare-generics`.
This version of the PR might have detrimental effects on performance as it makes lots of stuff dependent on a single query results (`upstream_monomorphizations_for(def_id_of_drop_in_place)`). That should be fixable but let's do a perf run first.
Potentially fixes issue https://github.com/rust-lang/rust/issues/64140. (cc @alexcrichton)
The changes here are related to @matthewjasper's https://github.com/rust-lang/rust/pull/67332 but should be mostly orthogonal.
r? @ghost
Enable ASan on Fuchsia
This change adds the x86_64-fuchsia and aarch64-fuchsia LLVM targets to
those allowed to invoke -Zsanitizer. Currently, the only overlap between
compiler_rt sanitizers supported by both rustc and Fuchsia is ASan.
Export weak symbols used by MemorySanitizer
Export weak symbols defined by MemorySanitizer instrumentation, which are used
to implement `-Zsanitizer-memory-track-origins` and `-Zsanitizer-recover=memory`.
Previously, when using fat LTO, they would internalized and eliminated.
Fixes#68367.
This change adds the x86_64-fuchsia and aarch64-fuchsia LLVM targets to
those allowed to invoke -Zsanitizer. Currently, the only overlap between
compiler_rt sanitizers supported by both rustc and Fuchsia is ASan.
build-std compatible sanitizer support
### Motivation
When using `-Z sanitizer=*` feature it is essential that both user code and
standard library is instrumented. Otherwise the utility of sanitizer will be
limited, or its use will be impractical like in the case of memory sanitizer.
The recently introduced cargo feature build-std makes it possible to rebuild
standard library with arbitrary rustc flags. Unfortunately, those changes alone
do not make it easy to rebuild standard library with sanitizers, since runtimes
are dependencies of std that have to be build in specific environment,
generally not available outside rustbuild process. Additionally rebuilding them
requires presence of llvm-config and compiler-rt sources.
The goal of changes proposed here is to make it possible to avoid rebuilding
sanitizer runtimes when rebuilding the std, thus making it possible to
instrument standard library for use with sanitizer with simple, although
verbose command:
```
env CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_RUSTFLAGS=-Zsanitizer=thread cargo test -Zbuild-std --target x86_64-unknown-linux-gnu
```
### Implementation
* Sanitizer runtimes are no long packed into crates. Instead, libraries build
from compiler-rt are used as is, after renaming them into `librusc_rt.*`.
* rustc obtains runtimes from target libdir for default sysroot, so that
they are not required in custom build sysroots created with build-std.
* The runtimes are only linked-in into executables to address issue #64629.
(in previous design it was hard to avoid linking runtimes into static
libraries produced by rustc as demonstrated by sanitizer-staticlib-link
test, which still passes despite changes made in #64780).
cc @kennytm, @japaric, @firstyear, @choller
Export public scalar statics in wasm
Fixes#67453
I am not sure which export level statics should get when exporting them in wasm. This small change fixes the issue that I had, but this might not be the correct way to implement this.
