rust/library/std
bors 3d0c847d33 Auto merge of #74941 - dylanmckay:replace-broken-avr-unknown-unknown-target, r=oli-obk
[AVR] Replace broken 'avr-unknown-unknown' target with 'avr-unknown-gnu-atmega328' target

The `avr-unknown-unknown` target has never worked correctly, always trying to invoke
the host linker and failing. It aimed to be a mirror of AVR-GCC's
default handling of the `avr-unknown-unknown' triple (assume bare
minimum chip features, silently skip linking runtime libraries, etc).
This behaviour is broken-by-default as it will cause a miscompiled executable
when flashed.

This patch improves the AVR builtin target specifications to instead
expose only a 'avr-unknown-gnu-atmega328' target. This target system is
`gnu`, as it uses the AVR-GCC frontend along with avr-binutils. The
target triple ABI is 'atmega328'.

In the future, it should be possible to replace the dependency on
AVR-GCC and binutils by using the in-progress AVR LLD and compiler-rt support.
Perhaps at that point it would make sense to add an
'avr-unknown-unknown-atmega328' target as a better default when
implemented.

There is no current intention to add in-tree AVR target specifications for other
AVR microcontrollers - this one can serve as a reference implementation
for other devices via `rustc --print target-spec-json
avr-unknown-gnu-atmega328p`.

There should be no users of the existing 'avr-unknown-unknown' Rust
target as a custom target specification JSON has always been
recommended, and the avr-unknown-unknown target could never pass the
linking step anyway.
2020-08-27 15:48:56 +00:00
..
benches
src Auto merge of #75947 - pietroalbini:bootstrap-update, r=Mark-Simulacrum 2020-08-27 09:24:51 +00:00
tests
build.rs [AVR] Rename the last few remaining references from 'avr-unknown-unknown' to 'avr-unknown-gnu-atmega328' 2020-08-24 18:45:24 +12:00
Cargo.toml Bump std's libc version to 0.2.74 2020-08-14 00:37:19 -07:00