[gcc/devel/rust/master] Merge #1406

[gcc/devel/rust/master] Merge #1406

[Thomas Schwinge]

https://gcc.gnu.org/g:dec7ee4c5e703422ecb9bc94417645d66af7eaae

commit dec7ee4c5e703422ecb9bc94417645d66af7eaae
Merge: 15d4bdd84a7 8dc692afc2c
Author: bors[bot] <26634292+bors[bot]@users.noreply.github.com>
Date:   Fri Jul 22 13:40:06 2022 +0000

    Merge #1406
    
    1406: Add Attribute checking visitor r=CohenArthur a=CohenArthur
    
    This PR adds a new attribute checker visitor. Its role is to take care of validating builtin attributes and their inputs.
    
    This is currently a draft as there are multiple issues:
    
    1. The visitor is not complete
    2. The lexer is broken, but was also broken before in that it didn't allow multiline string literals. There is a FIXME asking for how to check for an `EOF` character when parsing UTF-8 strings
    3. The checking of attributes is very limited. Currently, only the `#[doc(alias = "...")]` is being checked. This is incomplete.
    
    I'm looking for feedback on the implementation and advice for my issues. Thanks :)
    
    Co-authored-by: Arthur Cohen <arthur.cohen@embecosm.com>

Diff:

 gcc/rust/hir/rust-ast-lower-base.cc                |   2 +
 gcc/rust/lex/rust-codepoint.h                      |   4 +-
 gcc/rust/lex/rust-lex.cc                           |  49 +-
 gcc/rust/rust-session-manager.cc                   |   3 +
 gcc/rust/util/rust-attributes.cc                   | 767 +++++++++++++++++++++
 gcc/rust/util/rust-attributes.h                    | 200 ++++++
 .../rust/compile/torture/check-doc-attr-string.rs  |  11 +-
 .../rust/compile/torture/undended-string-1.rs      |   5 +
 .../rust/compile/torture/undended-string-2.rs      |   5 +
 9 files changed, 1023 insertions(+), 23 deletions(-)