[gccrs COMMIT 3/3] gccrs: Add new checks for `#[repr(align)]` attribute

[gerris . rs]

From: Yap Zhi Heng <yapz...@gmail.com>

gcc/rust/ChangeLog:

        * typecheck/rust-hir-type-check-base.cc 
(TypeCheckBase::parse_repr_options): New
        check for `#[repr(align)]` to enforce having a parameter that is a 
power of 2.

gcc/testsuite/ChangeLog:

        * rust/compile/invalid_repr_hint.rs: Update existing and add new 
`align` test cases.

Signed-Off-By: Yap Zhi Heng <yapz...@gmail.com>
---
This change was merged into the gccrs repository and is posted here for
upstream visibility and potential drive-by review, as requested by GCC
release managers.
Each commit email contains a link to its details on github from where you can
find the Pull-Request and associated discussions.


Commit on github: 
https://github.com/Rust-GCC/gccrs/commit/864defecb6c0faf055005b48a24914651ef5c727

The commit has NOT been mentioned in any issue.

The commit has been mentioned in the following pull-request(s):
 - https://github.com/Rust-GCC/gccrs/pull/4650

 gcc/rust/typecheck/rust-hir-type-check-base.cc  | 13 +++++++++++++
 gcc/testsuite/rust/compile/invalid_repr_hint.rs |  5 ++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/gcc/rust/typecheck/rust-hir-type-check-base.cc 
b/gcc/rust/typecheck/rust-hir-type-check-base.cc
index 7ff37c924..f966f002a 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-base.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-base.cc
@@ -522,6 +522,15 @@ TypeCheckBase::parse_repr_options (const AST::AttrVec 
&attrs, location_t locus)
 
          if (oparen == std::string::npos)
            {
+             if (inline_option.compare ("align") == 0)
+               {
+                 rust_error_at (attr.get_locus (), ErrorCode::E0589,
+                                "invalid %<repr(align)%> attribute: %<align%> "
+                                "needs an argument");
+                 delete meta_items;
+                 break;
+               }
+
              is_pack = inline_option.compare ("packed") == 0;
              is_c = inline_option.compare ("C") == 0;
              is_integer = (inline_option.compare ("isize") == 0
@@ -571,6 +580,10 @@ TypeCheckBase::parse_repr_options (const AST::AttrVec 
&attrs, location_t locus)
            }
          else if (is_align)
            {
+             if (value == 0 || (value & (value - 1)) != 0)
+               rust_error_at (
+                 attr.get_locus (), ErrorCode::E0589,
+                 "invalid %<repr(align)%> attribute: not a power of two");
              repr.repr_kind = TyTy::ADTType::ReprKind::ALIGN;
              repr.align = value;
            }
diff --git a/gcc/testsuite/rust/compile/invalid_repr_hint.rs 
b/gcc/testsuite/rust/compile/invalid_repr_hint.rs
index 7ac48a921..5e1af4d1c 100644
--- a/gcc/testsuite/rust/compile/invalid_repr_hint.rs
+++ b/gcc/testsuite/rust/compile/invalid_repr_hint.rs
@@ -6,7 +6,10 @@ struct Foo {
     x: i32,
 }
 
-#[repr(align)] // { dg-error "unrecognized representation hint" }
+#[repr(align)] // { dg-error "invalid .repr.align.. attribute: .align. needs 
an argument" }
 struct Bar {
     x: i32,
 }
+
+#[repr(align(3))] // { dg-error "invalid .repr.align.. attribute: not a power 
of two" }
+struct Baz {}
-- 
2.54.0