As discussed at <rust-lang#122106>, use the
crate encoding to represent new primitives.

As discussed at <rust-lang#122106>, use the
crate encoding to represent new primitives.

As discussed at <rust-lang#122106>, use the
crate encoding to represent new primitives.

…lwoerister

Add v0 symbol mangling for `f16` and `f128`

As discussed at <rust-lang#122106>, use the crate encoding to represent new primitives.

As discussed at <rust-lang#122106>, use the
crate encoding to represent new primitives.

(cherry picked from commit 809b84e)

…r-demangling-recommendation, r=davidtwco

Recommend to never display zero disambiguators when demangling v0 symbols

This PR extends the [v0 symbol mangling documentation](https://doc.rust-lang.org/rustc/symbol-mangling/v0.html) with the strong recommendation that demanglers should never display zero-disambiguators, especially when dealing with `crate-root`.

Being able to rely on `C3foo` to be rendered as `foo` (i.e. without explicit disambiguator value) rather than as `foo[0]` allows the compiler to encode things like new basic types in a backward compatible way. This idea has been originally proposed by `@eddyb` in [the discussion around supporting `f16` and `f128` in the v0 mangling scheme](rust-lang#122106). It is a generally useful mechanism for supporting a certain class of new elements in the v0 mangling scheme in a backward compatible way (whether as a temporary workaround until downstream tooling has picked up grammar changes or as a permanent encoding).

cc `@tgross35`

Rollup merge of rust-lang#124514 - michaelwoerister:zero-disambiguator-demangling-recommendation, r=davidtwco

Recommend to never display zero disambiguators when demangling v0 symbols

This PR extends the [v0 symbol mangling documentation](https://doc.rust-lang.org/rustc/symbol-mangling/v0.html) with the strong recommendation that demanglers should never display zero-disambiguators, especially when dealing with `crate-root`.

Being able to rely on `C3foo` to be rendered as `foo` (i.e. without explicit disambiguator value) rather than as `foo[0]` allows the compiler to encode things like new basic types in a backward compatible way. This idea has been originally proposed by `@eddyb` in [the discussion around supporting `f16` and `f128` in the v0 mangling scheme](rust-lang#122106). It is a generally useful mechanism for supporting a certain class of new elements in the v0 mangling scheme in a backward compatible way (whether as a temporary workaround until downstream tooling has picked up grammar changes or as a permanent encoding).

cc `@tgross35`