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
This commit builds on #65501 continue to simplify the build system and
compiler now that we no longer have multiple LLVM backends to ship by
default. Here this switches the compiler back to what it once was long
long ago, which is linking LLVM directly to the compiler rather than
dynamically loading it at runtime. The `codegen-backends` directory of
the sysroot no longer exists and all relevant support in the build
system is removed. Note that `rustc` still supports a dynamically loaded
codegen backend as it did previously, it just no longer supports
dynamically loaded codegen backends in its own sysroot.
Additionally as part of this the `librustc_codegen_llvm` crate now once
again explicitly depends on all of its crates instead of implicitly
loading them through the sysroot. This involved filling out its
`Cargo.toml` and deleting all the now-unnecessary `extern crate`
annotations in the header of the crate. (this in turn required adding a
number of imports for names of macros too).
The end results of this change are:
* Rustbuild's build process for the compiler as all the "oh don't forget
the codegen backend" checks can be easily removed.
* Building `rustc_codegen_llvm` is much simpler since it's simply
another compiler crate.
* Managing the dependencies of `rustc_codegen_llvm` is much simpler since
it's "just another `Cargo.toml` to edit"
* The build process should be a smidge faster because there's more
parallelism in the main rustc build step rather than splitting
`librustc_codegen_llvm` out to its own step.
* The compiler is expected to be slightly faster by default because the
codegen backend does not need to be dynamically loaded.
* Disabling LLVM as part of rustbuild is still supported, supporting
multiple codegen backends is still supported, and dynamic loading of a
codegen backend is still supported.
This commit changes the return type of `Builder::cargo` to return a
builder that allows dynamically adding more `RUSTFLAGS` values
after-the-fact. While not used yet, this will later be used to delete
more of `rustc.rs`
Previously when building documentation for the standard library we'd
copy all the files 5 times, and these files include libcore/libstd docs
which are huge! This commit instead only copies the files after rustdoc
has been run for each crate, reducing the number of redundant copies
we're making.
Fix build failure in case file doesn't exist
It fixes the following issue:
```bash
$ ./x.py test src/tools/linkchecker ./build/x86_64-apple-darwin/doc/ --stage 1
Updating only changed submodules
Submodules updated in 0.05 seconds
Finished dev [unoptimized] target(s) in 0.15s
thread 'main' panicked at 'source "/Users/imperio/rust/rust/build/x86_64-apple-darwin/doc/version_info.html" failed to get metadata: No such file or directory (os error 2)', src/build_helper/lib.rs:179:19
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
failed to run: /Users/imperio/rust/rust/build/bootstrap/debug/bootstrap test src/tools/linkchecker ./build/x86_64-apple-darwin/doc/ --stage 1
Build completed unsuccessfully in 0:00:01
```
If the file doesn't exist, it makes sense anyway to just run the command in order to generate it.
r? @Mark-Simulacrum
Since its inception rustbuild has always worked in three stages: one for
libstd, one for libtest, and one for rustc. These three stages were
architected around crates.io dependencies, where rustc wants to depend
on crates.io crates but said crates don't explicitly depend on libstd,
requiring a sysroot assembly step in the middle. This same logic was
applied for libtest where libtest wants to depend on crates.io crates
(`getopts`) but `getopts` didn't say that it depended on std, so it
needed `std` built ahead of time.
Lots of time has passed since the inception of rustbuild, however,
and we've since gotten to the point where even `std` itself is depending
on crates.io crates (albeit with some wonky configuration). This
commit applies the same logic to the two dependencies that the `test`
crate pulls in from crates.io, `getopts` and `unicode-width`. Over the
many years since rustbuild's inception `unicode-width` was the only
dependency picked up by the `test` crate, so the extra configuration
necessary to get crates building in this crate graph is unlikely to be
too much of a burden on developers.
After this patch it means that there are now only two build phasese of
rustbuild, one for libstd and one for rustc. The libtest/libproc_macro
build phase is all lumped into one now with `std`.
This was originally motivated by rust-lang/cargo#7216 where Cargo was
having to deal with synthesizing dependency edges but this commit makes
them explicit in this repository.
This is no longer used by the index generator and was always an unstable
compiler detail, so strip it out.
This also leaves in RUSTC_ERROR_METADATA_DST since the stage0 compiler
still needs it to be set.
ci: Attempt to skip a full rustc compile on dist*
Currently when we're preparing cross-compiled compilers it can take
quite some time because we have to build the compiler itself three
different times. The first is the normal bootstrap, the second is a
second build for the build platform, and the third is the actual target
architecture compiler. The second compiler was historically built
exclusively for procedural macros, and long ago we didn't actually need
it.
This commit tries out avoiding that second compiled compiler, meaning we
only compile rustc for the build platform only once. Some local testing
shows that this is promising, but bors is of course the ultimate test!
This commit furthers the previous one to ensure that we don't build an
extra stage of the compiler in CI. A test has been added to rustbuild to
ensure that this doesn't regress, and then in debugging this test it was
hunted down that the `dist::Std` target was the one erroneously pulling
in the wrong compiler.
The `dist::Std` step was updated to instead account for the "full
bootstrap" or not flag, ensuring that the correct compiler for compiling
the final standard library was used. This was another use of the
`force_use_stage1` function which was in theory supposed to be pretty
central, so existing users were all evaluated and a new function,
`Builder::compiler_for`, was introduced. All existing users of
`force_use_stage1` have been updated to use `compiler_for`, where the
semantics of `compiler_for` are similar to that of `compiler` except
that it doesn't guarantee the presence of a sysroot for the arguments
passed (as they may be modified).
Perhaps one day we can unify `compiler` and `compiler_for`, but the
usage of `Builder::compiler` is so ubiquitous it would take quite some
time to evaluate whether each one needs the sysroot or not, so it's
hoped that can be done in parallel.
Exclude old book redirect stubs from search engines
Adds `<meta name="robots" content="noindex,follow">` to the `<head>` of old stub pages pointing to the second edition of the book.
This is continuation of https://github.com/rust-lang/book/pull/1788
Rustdoc remove old style files
Reopening of #56577 (which I can't seem to reopen...).
I made the flag unstable so with this change, what was blocking the PR is now gone I assume.
David Tolnay
Eric Huss
Nicholas Nethercote
Alex Tokarev
Matthias Krüger
bors
Yuki Okushi
Oliver Middleton
Tomasz Miąsko
Andy Russell
Mark Rousskov
Alex Crichton
Guillaume Gomez
Mateusz Mikuła
Carol (Nichols || Goulding)
Mazdak Farrokhzad
Kornel
Taiki Endo
kennytm
Alexander Regueiro
James Munns