In #56986 the linkage of jemalloc to the compiler was switched from the
driver library to the rustc binary to ensure that only rustc itself uses
jemalloc. In doing so, however, it turns out jemalloc wasn't actually
linked in at all! None of the symbols were referenced so the static
library wasn't used. This means that jemalloc wasn't pulled in at all.
This commit performs a bit of a dance to reference jemalloc symbols,
attempting to pull it in despite LLVM's optimizations.
Closes#57115
This commit moves jemalloc to just the rustc binary rather than the
rustc_driver shared library, enusring that it's only used for binaries
that opt-in to it like rustc rather than other binaries using
librustc_driver like rustdoc/rls/etc. This will hopefully address #56980
Prevent broken pipes causing ICEs
As the private `std::io::print_to` panics if there is an I/O error, which is used by `println!`, the compiler would ICE if one attempted to use a broken pipe (e.g. `rustc --help | false`). This introduces a new (private) macro `try_println!` which allows us to avoid this.
As a side note, it seems this macro might be useful publicly (and actually there seems to be [a crate specifically for this purpose](https://crates.io/crates/try_print/)), though that can probably be left for a future discussion.
One slight alternative approach would be to simply early exit without an error (i.e. exit code `0`), which [this comment](https://github.com/rust-lang/rust/issues/34376#issuecomment-377822526) suggests is the usual approach. I've opted not to take that approach initially, because I think it's more helpful to know when there is a broken pipe.
Fixes#34376.
This commit is the start of a series of commits which start to replace the
makefiles with a Cargo-based build system. The aim is not to remove the
makefiles entirely just yet but rather just replace the portions that invoke the
compiler to do the bootstrap. This commit specifically adds enough support to
perform the bootstrap (and all the cross compilation within) along with
generating documentation.
More commits will follow up in this series to actually wire up the makefiles to
call this build system, so stay tuned!
