libiberty: Support the new ("v0") mangling scheme in rust-demangle

This is the libiberty (mainly for binutils/gdb) counterpart of
https://github.com/alexcrichton/rustc-demangle/pull/23.

Relevant links for the new Rust mangling scheme (aka "v0"):
* Rust RFC: https://github.com/rust-lang/rfcs/pull/2603
* tracking issue: https://github.com/rust-lang/rust/issues/60705
* implementation: https://github.com/rust-lang/rust/pull/57967

This implementation includes full support for UTF-8 identifiers
via punycode, so I've included a testcase for that as well.

libiberty/ChangeLog:
	* rust-demangle.c (struct rust_demangler): Add
	skipping_printing and bound_lifetime_depth fields.
	(eat): Add (v0-only).
	(parse_integer_62): Add (v0-only).
	(parse_opt_integer_62): Add (v0-only).
	(parse_disambiguator): Add (v0-only).
	(struct rust_mangled_ident): Add punycode{,_len} fields.
	(parse_ident): Support v0 identifiers.
	(print_str): Respect skipping_printing.
	(print_uint64): Add (v0-only).
	(print_uint64_hex): Add (v0-only).
	(print_ident): Respect skipping_printing,
	Support v0 identifiers.
	(print_lifetime_from_index): Add (v0-only).
	(demangle_binder): Add (v0-only).
	(demangle_path): Add (v0-only).
	(demangle_generic_arg): Add (v0-only).
	(demangle_type): Add (v0-only).
	(demangle_path_maybe_open_generics): Add (v0-only).
	(demangle_dyn_trait): Add (v0-only).
	(demangle_const): Add (v0-only).
	(demangle_const_uint): Add (v0-only).
	(basic_type): Add (v0-only).
	(rust_demangle_callback): Support v0 symbols.
	* testsuite/rust-demangle-expected: Add v0 testcases.

1 files changed, 133 insertions, 1 deletions

diff --git a/libiberty/testsuite/rust-demangle-expected b/libiberty/testsuite/rust-demangle-expected
index 74774794736..7dca315d005 100644
--- a/libiberty/testsuite/rust-demangle-expected
+++ b/libiberty/testsuite/rust-demangle-expected
@@ -11,7 +11,7 @@
 #
 ############
 #
-# Coverage Tests
+# Coverage Tests (legacy)
 #
 #
 # Demangles as rust symbol.
@@ -163,3 +163,135 @@ _ZN63_$LT$core..ptr..Unique$LT$T$GT$$u20$as$u20$core..ops..Deref$GT$5deref17h19f
 --format=rust
 _ZN11issue_609253foo37Foo$LT$issue_60925..llv$u6d$..Foo$GT$3foo17h059a991a004536adE
 issue_60925::foo::Foo<issue_60925::llvm::Foo>::foo
+--format=rust
+_ZN4core3ops8function6FnOnce40call_once$u7b$$u7b$vtable.shim$u7d$$u7d$17h000b1ad6c4f30bd6E
+core::ops::function::FnOnce::call_once{{vtable.shim}}
+#
+############
+#
+# Coverage Tests (v0)
+#
+#
+# Crate with a leading digit.
+--format=rust
+_RNvC6_123foo3bar
+123foo::bar
+# UTF-8 identifiers.
+--format=rust
+_RNqCs4fqI2P2rA04_11utf8_identsu30____7hkackfecea1cbdathfdh9hlq6y
+utf8_idents::საჭმელად_გემრიელი_სადილი
+# Closure path elements.
+--format=rust
+_RNCNCNgCs6DXkGYLi8lr_2cc5spawn00B5_
+cc::spawn::{closure#0}::{closure#0}
+#
+--format=rust
+_RNCINkXs25_NgCsbmNqQUJIY6D_4core5sliceINyB9_4IterhENuNgNoBb_4iter8iterator8Iterator9rpositionNCNgNpB9_6memchr7memrchrs_0E0Bb_
+<core::slice::Iter<u8> as core::iter::iterator::Iterator>::rposition::<core::slice::memchr::memrchr::{closure#1}>::{closure#0}
+# dyn Trait ("trait object") types.
+--format=rust
+_RINbNbCskIICzLVDPPb_5alloc5alloc8box_freeDINbNiB4_5boxed5FnBoxuEp6OutputuEL_ECs1iopQbuBiw2_3std
+alloc::alloc::box_free::<dyn alloc::boxed::FnBox<(), Output = ()>>
+# Types with const generics parameters.
+--format=rust
+_RNvMC0INtC8arrayvec8ArrayVechKj7b_E3new
+<arrayvec::ArrayVec<u8, 123>>::new
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_8UnsignedKhb_E
+<const_generic::Unsigned<11>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_6SignedKs98_E
+<const_generic::Signed<152>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_6SignedKanb_E
+<const_generic::Signed<-11>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_4BoolKb0_E
+<const_generic::Bool<false>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_4BoolKb1_E
+<const_generic::Bool<true>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_4CharKc76_E
+<const_generic::Char<'v'>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_4CharKca_E
+<const_generic::Char<'\n'>>
+#
+--format=rust
+_RMCs4fqI2P2rA04_13const_genericINtB0_4CharKc2202_E
+<const_generic::Char<'\u{2202}'>>
+#
+--format=rust
+_RNvNvMCs4fqI2P2rA04_13const_genericINtB4_3FooKpE3foo3FOO
+<const_generic::Foo<_>>::foo::FOO
+#
+# All of the tests above but in auto mode instead:
+#
+# Crate with a leading digit.
+--format=auto
+_RNvC6_123foo3bar
+123foo::bar
+# UTF-8 identifiers.
+--format=auto
+_RNqCs4fqI2P2rA04_11utf8_identsu30____7hkackfecea1cbdathfdh9hlq6y
+utf8_idents::საჭმელად_გემრიელი_სადილი
+# Closure path elements.
+--format=auto
+_RNCNCNgCs6DXkGYLi8lr_2cc5spawn00B5_
+cc::spawn::{closure#0}::{closure#0}
+#
+--format=auto
+_RNCINkXs25_NgCsbmNqQUJIY6D_4core5sliceINyB9_4IterhENuNgNoBb_4iter8iterator8Iterator9rpositionNCNgNpB9_6memchr7memrchrs_0E0Bb_
+<core::slice::Iter<u8> as core::iter::iterator::Iterator>::rposition::<core::slice::memchr::memrchr::{closure#1}>::{closure#0}
+# dyn Trait ("trait object") types.
+--format=auto
+_RINbNbCskIICzLVDPPb_5alloc5alloc8box_freeDINbNiB4_5boxed5FnBoxuEp6OutputuEL_ECs1iopQbuBiw2_3std
+alloc::alloc::box_free::<dyn alloc::boxed::FnBox<(), Output = ()>>
+# Types with const generics parameters.
+--format=auto
+_RNvMC0INtC8arrayvec8ArrayVechKj7b_E3new
+<arrayvec::ArrayVec<u8, 123>>::new
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_8UnsignedKhb_E
+<const_generic::Unsigned<11>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_6SignedKs98_E
+<const_generic::Signed<152>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_6SignedKanb_E
+<const_generic::Signed<-11>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_4BoolKb0_E
+<const_generic::Bool<false>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_4BoolKb1_E
+<const_generic::Bool<true>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_4CharKc76_E
+<const_generic::Char<'v'>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_4CharKca_E
+<const_generic::Char<'\n'>>
+#
+--format=auto
+_RMCs4fqI2P2rA04_13const_genericINtB0_4CharKc2202_E
+<const_generic::Char<'\u{2202}'>>
+#
+--format=auto
+_RNvNvMCs4fqI2P2rA04_13const_genericINtB4_3FooKpE3foo3FOO
+<const_generic::Foo<_>>::foo::FOO