Auto merge of #99422 - Dylan-DPC:rollup-htjofm6, r=Dylan-DPC

Rollup of 7 pull requests

Successful merges:

 - #98839 (Add assertion that `transmute_copy`'s U is not larger than T)
 - #98998 (Remove branch target prologues from `#[naked] fn`)
 - #99198 (add missing null ptr check in alloc example)
 - #99344 (rustdoc: avoid inlining items with duplicate `(type, name)`)
 - #99351 (Use `typeck_results` to get accurate qpath res for arg mismatch error)
 - #99378 (interpret/visitor: add missing early return)
 - #99394 (Add regression test for #95230)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -299,6 +299,12 @@ pub fn from_fn_attrs<'ll, 'tcx>(
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
         to_add.push(AttributeKind::Naked.create_attr(cx.llcx));
+        // HACK(jubilee): "indirect branch tracking" works by attaching prologues to functions.
+        // And it is a module-level attribute, so the alternative is pulling naked functions into new LLVM modules.
+        // Otherwise LLVM's "naked" functions come with endbr prefixes per https://github.com/rust-lang/rust/issues/98768
+        to_add.push(AttributeKind::NoCfCheck.create_attr(cx.llcx));
+        // Need this for AArch64.
+        to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false"));
     }
     if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::ALLOCATOR) {
         // apply to return place instead of function (unlike all other attributes applied in this function)

compiler/rustc_codegen_llvm/src/llvm/ffi.rs

@@ -191,6 +191,7 @@ pub enum AttributeKind {
     StackProtect = 32,
     NoUndef = 33,
     SanitizeMemTag = 34,
+    NoCfCheck = 35,
 }
 
 /// LLVMIntPredicate

compiler/rustc_const_eval/src/interpret/visitor.rs

@@ -473,6 +473,9 @@ macro_rules! make_value_visitor {
                         // The second `Box` field is the allocator, which we recursively check for validity
                         // like in regular structs.
                         self.visit_field(v, 1, &alloc)?;
+
+                        // We visited all parts of this one.
+                        return Ok(());
                     }
                     _ => {},
                 };

compiler/rustc_llvm/llvm-wrapper/LLVMWrapper.h

@@ -84,6 +84,7 @@ enum LLVMRustAttribute {
   StackProtect = 32,
   NoUndef = 33,
   SanitizeMemTag = 34,
+  NoCfCheck = 35,
 };
 
 typedef struct OpaqueRustString *RustStringRef;

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -176,6 +176,8 @@ static Attribute::AttrKind fromRust(LLVMRustAttribute Kind) {
     return Attribute::NoAlias;
   case NoCapture:
     return Attribute::NoCapture;
+  case NoCfCheck:
+    return Attribute::NoCfCheck;
   case NoInline:
     return Attribute::NoInline;
   case NonNull:

compiler/rustc_typeck/src/check/fn_ctxt/checks.rs

@@ -443,17 +443,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         // Next, let's construct the error
         let (error_span, full_call_span, ctor_of) = match &call_expr.kind {
             hir::ExprKind::Call(
-                hir::Expr {
-                    span,
-                    kind:
-                        hir::ExprKind::Path(hir::QPath::Resolved(
-                            _,
-                            hir::Path { res: Res::Def(DefKind::Ctor(of, _), _), .. },
-                        )),
-                    ..
-                },
+                hir::Expr { hir_id, span, kind: hir::ExprKind::Path(qpath), .. },
                 _,
-            ) => (call_span, *span, Some(of)),
+            ) => {
+                if let Res::Def(DefKind::Ctor(of, _), _) =
+                    self.typeck_results.borrow().qpath_res(qpath, *hir_id)
+                {
+                    (call_span, *span, Some(of))
+                } else {
+                    (call_span, *span, None)
+                }
+            }
             hir::ExprKind::Call(hir::Expr { span, .. }, _) => (call_span, *span, None),
             hir::ExprKind::MethodCall(path_segment, _, span) => {
                 let ident_span = path_segment.ident.span;