This reverts commit 8b9c539.

Brings in WebAssembly/wasi-libc#184 which can help standalone programs
with environment variables!

…s sense.

…info=1.

…r -Cdebuginfo=1.

…debuginfo=1.

…-a-bar, r=michaelwoerister

rustc_codegen_llvm: don't generate any type debuginfo for -Cdebuginfo=1.

Works towards rust-lang#69074 by adding more checks for `DebugInfo::Full` in a few places in `rustc_codegen_llvm`, bringing us in line with what `clang -g1` generates (no debuginfo types, nor debuginfo for `static`s).

<hr/>

My local build's (`debuginfo-level=1`, `debug-assertions=1`) `librustc_driver-*.so` went from just over 1GiB (1019MiB) down to 402MiB.

It's still bad, but the `.debug_*` sections themselves (as reported by `objdump`) went from something like 853MiB down to 236MiB, i.e. roughly a 3.6x reduction.

<hr/>

Sadly, I don't think this is enough to justify *shipping* all of this debuginfo, but now it's more plausible that we could at least *build* with `debuginfo-level=1` *then* strip it.
That would give us real backtraces for e.g. ICEs during builds, but I don't know how often that's relevant.

We could also look into split DWARF, and maybe have a `rustc-debuginfo` component in `rustup`.

There's also the possibility of making it slimmer by omitting parameters to functions, or perhaps some deduplication (I think right now there is no DWARF reuse across CGUs? maybe ThinLTO helps?).

r? @michaelwoerister cc @rust-lang/wg-codegen @alexcrichton @Mark-Simulacrum

librustc_codegen_llvm: Replace deprecated API usage

…hewjasper

Increase verbosity when suggesting subtle code changes

Do not suggest changes that are actually quite small inline, to minimize the likelihood of confusion.

Fix rust-lang#69243.

…komatsakis

rustc: keep upvars tupled in {Closure,Generator}Substs.

Previously, each closure/generator capture's (aka "upvar") type was tracked as one "synthetic" type parameter in the closure/generator substs, and figuring out where the parent `fn`'s generics end and the synthetics start involved slicing at `tcx.generics_of(def_id).parent_count`.

Needing to query `generics_of` limited @davidtwco (who wants to compute some `TypeFlags` differently for parent generics vs upvars, and `TyCtxt` is not available there), which is how I got started on this, but it's also possible that the `generics_of` queries are slowing down `{Closure,Generator}Substs` methods.

To give an example, for a `foo::<T, U>::{closure#0}` with captures `x: X` and `y: Y`, substs are:
* before this PR: `[T, U, /*kind*/, /*signature*/, X, Y]`
* after this PR: `[T, U, /*kind*/, /*signature*/, (X, Y)]`

You can see that, with this PR, no matter how many captures, the last 3 entries in the substs (or 5 for a generator) are always the "synthetic" ones, with the last one being the tuple of capture types.

r? @nikomatsakis cc @Zoxc

…crum

Ensure LLVM is in the link path for rustc tools

The build script for `rustc_llvm` outputs LLVM information in `cargo:rustc-link-lib` and `cargo:rustc-link-search` so the compiler can be linked correctly. However, while the lib is carried along in metadata, the search paths are not. So when cargo is invoked again later for rustc _tools_, they'll also try to link with LLVM, but the necessary paths may be left out.

Rustbuild can use the environment to set the LLVM link path for tools -- `LIB` for MSVC toolchains and `LIBRARY_PATH` for everyone else.

Fixes rust-lang#68714.

…lbini

Update the bundled wasi-libc with libstd

Brings in WebAssembly/wasi-libc#184 which can help standalone programs
with environment variables!

…morse

resolve: Do not resolve visibilities on proc macro definitions twice

Fixes rust-lang#68921

…nkov

Miri error type: remove UbExperimental variant

In rust-lang/miri#1250, I will move Miri away from that variant, and use a custom `MachineStop` exception instead.