This patch basically adds a target option for omitting the `-nodefaultlibs` flag when invoking the linker. I am not sure if this is the correct or only way to approach this problem, so any feedback is welcome.
Motivation: I'm currently working on a Rust target specification for the [rumprun](/rumpkernel/rumprun) unikernel. rumprun is based on rump kernels and uses NetBSDs libc and drivers to provide a POSIXy environment. It provides its own linker wrapper that generates binaries which can be "baked" into a unikernel after configuration. Using `-nodefaultlibs` on the rumprun linker will prevent it from selecting the search paths for the rumprun libraries. My current target implementation for rumprun is here: gandro/rust@295744b2ee
Currently, only a target that `is_like_windows` will omit the `-nodefaultlibs` flag, but since rumprun is not like Windows otherwise, I think a separate flag makes more sense. This might be a breaking change for target specifications that have the `is_like_windows` option set to true. Such targets need to set `no_default_libraries` to false in order to restore the old behavior.
The registration of `panicking::on_panic` as a general-purpose
callback is overcomplicated and can fail.
Instead, invoking it explicitly removes the need for locking and paves
the way for further improvements.
If set to false, `-nodefaultlibs` is not passed to the linker. This
was the default behavior on Windows, but it should be configurable
per target.
This is a [breaking-change] for target specifications that have
the `is_like_windows` option set to true. Such targets need to
set `no_default_libraries` to false in order to restore the old
behavior.
Since 1.3.0 the BufWriter has seen tremendous speedups. So when I use it in the shootout benchmarks, I see some nice speedup (which up to 1.2.0 was nixed by the pessimizations during initialization).
With -O2, LLVM's inliner can remove this code, but this does not happen
with -O1 and lower. As a result, dropping Vec<u8> was linear with length,
resulting in abysmal performance for large buffers.
See issue #24280.
Move private bignum module to core::num, because it is not only used in flt2dec.
Extract private 80-bit soft-float into new core::num module for the same reason.
This breaks out some of the lints defined in `librustc_lint/builtin.rs` into two new modules: `unused` for the `UNUSED_*` lints and `bad_style` for the various style related lints as suggested in #22206. `builtin.rs` could probably get broken up more but this is a start.
By default, the linker in use under OpenBSD is the linker of base, which
don't include /usr/local/lib where libstdc++ of gcc-4.9 lives. We need
to add this directory to linker-path-search (using -L).
Search the path of libstdc++.a, which is a known name (libstdc++.so has
SO_VERSION) in the same directory.
r? @alexcrichton
this commit needs #28495 to be commited first. It should be the last piece for building rustc under OpenBSD from scratch.
