rustc_target: Remove some redundant target properties
`is_like_emscripten` is equivalent to `os == "emscripten"`, so it's removed.
`is_like_fuchsia` is equivalent to `os == "fuchsia"`, so it's removed.
`is_like_osx` also falls into the same category and is equivalent to `vendor == "apple"`, but it's commonly used so I kept it as is for now.
`is_like_(solaris,windows,wasm)` are combinations of different operating systems or architectures (see compiler/rustc_target/src/spec/tests/tests_impl.rs) so they are also kept as is.
I think `is_like_wasm` (and maybe `is_like_osx`) are sufficiently closed sets, so we can remove these fields as well and replace them with methods like `fn is_like_wasm() { arch == "wasm32" || arch == "wasm64" }`.
On other hand, `is_like_solaris` and `is_like_windows` are sufficiently open and I can imagine custom targets introducing other values for `os`.
This is kind of a gray area.
This is a debug setting. We should only make debug builds if user requests
a debug build. Currently this is inserted in release builds.
Furthermore, it would be better to insert these settings in --pre-link-args
because then it would be possible to override them if appropriate. Because
these are inserted at the end, it is necessary to patch emscripten to remove
them.
This enables us to set more generic labels shared between targets. For
example `target_family="wasm"` across all targets that are conceptually
"wasm".
See https://github.com/rust-lang/reference/pull/1006
Remove --export-dynamic from the link arguments on the wasm32-wasi
target, as it emits spurious exports and increases code size.
Leave it in place for wasm32-unknown-unknown and
wasm32-unknown-emscripten. Even though it isn't a great solution
there, users are likely depending on its behavior there.
Also change target_pointer_width to pointer_width.
Preparation for a subsequent type change of
target_pointer_width to an integer together with a rename
to pointer_width.
On its own, this commit breaks the build. I don't like making
build-breaking commits, but in this instance I believe that it
makes review easier, as the "real" changes of this PR can be
seen much more easily.
Result of running:
find compiler/rustc_target/src/spec/ -type f -exec sed -i -e 's/target_pointer_width: "\(.*\)"\..*,/pointer_width: \1,/g' {} \;
