add handling for mod_init_funcs linker directive on macOS

Author: ibraheemdev

src/helpers.rs

@@ -1236,7 +1236,12 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
     }
 
     /// Lookup an array of immediates stored as a linker section of name `name`.
-    fn lookup_link_section(&mut self, name: &str) -> InterpResult<'tcx, Vec<ImmTy<'tcx>>> {
+    ///
+    /// Any sections to which the provided equality function returns `true` will be included.
+    fn lookup_link_section(
+        &mut self,
+        eq: impl Fn(&str) -> bool,
+    ) -> InterpResult<'tcx, Vec<ImmTy<'tcx>>> {
         let this = self.eval_context_mut();
         let tcx = this.tcx.tcx;
 
@@ -1247,7 +1252,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             let Some(link_section) = attrs.link_section else {
                 return interp_ok(());
             };
-            if link_section.as_str() == name {
+            if eq(link_section.as_str()) {
                 let instance = ty::Instance::mono(tcx, def_id);
                 let const_val = this.eval_global(instance).unwrap_or_else(|err| {
                     panic!(

src/shims/ctor.rs

@@ -31,22 +31,35 @@ impl<'tcx> GlobalCtorState<'tcx> {
                     let this = this.eval_context_mut();
 
                     // Lookup constructors from the relevant magic link section.
-                    let link_section = match this.tcx.sess.target.binary_format {
+                    let ctors = match this.tcx.sess.target.binary_format {
                         // Read the CRT library section on Windows.
-                        BinaryFormat::Coff => ".CRT$XCU",
-
-                        // Read `__mod_init_func` on macOS.
-                        BinaryFormat::MachO => "__DATA,__mod_init_func",
+                        BinaryFormat::Coff =>
+                            this.lookup_link_section(|section| section == ".CRT$XCU")?,
+
+                        // Read the `__mod_init_func` section on macOS.
+                        BinaryFormat::MachO =>
+                            this.lookup_link_section(|section| {
+                                let mut parts = section.splitn(3, ',');
+                                let (segment_name, section_name, section_type) =
+                                    (parts.next(), parts.next(), parts.next());
+
+                                segment_name == Some("__DATA")
+                                    && section_name == Some("__mod_init_func")
+                                    // The `mod_init_funcs` directive ensures that the `S_MOD_INIT_FUNC_POINTERS` flag
+                                    // is set on the section, but it is not strictly required.
+                                    && matches!(section_type, None | Some("mod_init_funcs"))
+                            })?,
 
                         // Read the standard `.init_array` section on platforms that use ELF, or WASM,
                         // which supports the same linker directive.
-                        BinaryFormat::Elf | BinaryFormat::Wasm => ".init_array",
+                        BinaryFormat::Elf | BinaryFormat::Wasm =>
+                            this.lookup_link_section(|section| section == ".init_array")?,
 
                         // Other platforms have no global ctor support.
                         _ => break 'new_state Done,
                     };
 
-                    break 'new_state Ctors(this.lookup_link_section(link_section)?);
+                    break 'new_state Ctors(ctors);
                 }
                 Ctors(ctors) => {
                     if let Some(ctor) = ctors.pop() {

src/shims/tls.rs

@@ -302,7 +302,7 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
         // Windows has a special magic linker section that is run on certain events.
         // We don't support most of that, but just enough to make thread-local dtors in `std` work.
-        interp_ok(this.lookup_link_section(".CRT$XLB")?)
+        interp_ok(this.lookup_link_section(|section| section == ".CRT$XLB")?)
     }
 
     fn schedule_windows_tls_dtor(&mut self, dtor: ImmTy<'tcx>) -> InterpResult<'tcx> {

tests/pass/shims/ctor.rs

@@ -27,7 +27,7 @@ macro_rules! ctor {
         #[cfg_attr(windows, link_section = ".CRT$XCU")]
         #[cfg_attr(
             any(target_os = "macos", target_os = "ios"),
-            link_section = "__DATA,__mod_init_func"
+            link_section = "__DATA,__mod_init_func,mod_init_funcs"
         )]
         #[used]
         static $ident: unsafe extern "C" fn() = $ctor;