diff --git a/src/Zcu/PerThread.zig b/src/Zcu/PerThread.zig
index 6475649a68..ffc103310b 100644
--- a/src/Zcu/PerThread.zig
+++ b/src/Zcu/PerThread.zig
@@ -4461,6 +4461,22 @@ fn runCodegenInner(pt: Zcu.PerThread, func_index: InternPool.Index, air: *Air) e
     }
 
     const lf = comp.bin_file orelse return error.NoLinkFile;
+
+    // TODO: self-hosted codegen should always have a type of MIR; codegen should produce that MIR,
+    // and the linker should consume it. However, our SPIR-V backend is currently tightly coupled
+    // with our SPIR-V linker, so needs to work more like the LLVM backend. This should be fixed to
+    // unblock threaded codegen for SPIR-V.
+    if (lf.cast(.spirv)) |spirv_file| {
+        assert(pt.tid == .main); // SPIR-V has a lot of shared state
+        spirv_file.object.updateFunc(pt, func_index, air, &liveness) catch |err| {
+            switch (err) {
+                error.OutOfMemory => comp.link_diags.setAllocFailure(),
+            }
+            return error.CodegenFail;
+        };
+        return error.BackendDoesNotProduceMir;
+    }
+
     return codegen.generateFunction(lf, pt, zcu.navSrcLoc(nav), func_index, air, &liveness) catch |err| switch (err) {
         error.OutOfMemory,
         error.CodegenFail,
diff --git a/src/codegen/spirv.zig b/src/codegen/spirv.zig
index e6c06d9f20..b9eb56dd23 100644
--- a/src/codegen/spirv.zig
+++ b/src/codegen/spirv.zig
@@ -250,12 +250,12 @@ pub const Object = struct {
         self: *Object,
         pt: Zcu.PerThread,
         func_index: InternPool.Index,
-        air: Air,
-        liveness: Air.Liveness,
+        air: *const Air,
+        liveness: *const Air.Liveness,
     ) !void {
         const nav = pt.zcu.funcInfo(func_index).owner_nav;
         // TODO: Separate types for generating decls and functions?
-        try self.genNav(pt, nav, air, liveness, true);
+        try self.genNav(pt, nav, air.*, liveness.*, true);
     }
 
     pub fn updateNav(
diff --git a/src/link.zig b/src/link.zig
index f49acbf3d6..577d7ba82c 100644
--- a/src/link.zig
+++ b/src/link.zig
@@ -758,8 +758,8 @@ pub const File = struct {
         assert(base.comp.zcu.?.llvm_object == null);
         switch (base.tag) {
             .lld => unreachable,
+            .spirv => unreachable, // see corresponding special case in `Zcu.PerThread.runCodegenInner`
             inline else => |tag| {
-                if (tag == .spirv) @panic("MLUGG TODO");
                 dev.check(tag.devFeature());
                 return @as(*tag.Type(), @fieldParentPtr("base", base)).updateFunc(pt, func_index, mir, maybe_undef_air);
             },
diff --git a/src/link/SpirV.zig b/src/link/SpirV.zig
index 8b6b99525f..bafefccfc0 100644
--- a/src/link/SpirV.zig
+++ b/src/link/SpirV.zig
@@ -111,24 +111,6 @@ pub fn deinit(self: *SpirV) void {
     self.object.deinit();
 }
 
-pub fn updateFunc(
-    self: *SpirV,
-    pt: Zcu.PerThread,
-    func_index: InternPool.Index,
-    air: Air,
-    liveness: Air.Liveness,
-) link.File.UpdateNavError!void {
-    if (build_options.skip_non_native) {
-        @panic("Attempted to compile for architecture that was disabled by build configuration");
-    }
-
-    const ip = &pt.zcu.intern_pool;
-    const func = pt.zcu.funcInfo(func_index);
-    log.debug("lowering function {}", .{ip.getNav(func.owner_nav).name.fmt(ip)});
-
-    try self.object.updateFunc(pt, func_index, air, liveness);
-}
-
 pub fn updateNav(self: *SpirV, pt: Zcu.PerThread, nav: InternPool.Nav.Index) link.File.UpdateNavError!void {
     if (build_options.skip_non_native) {
         @panic("Attempted to compile for architecture that was disabled by build configuration");
diff --git a/src/target.zig b/src/target.zig
index a408c82c14..02e64670d0 100644
--- a/src/target.zig
+++ b/src/target.zig
@@ -850,8 +850,8 @@ pub inline fn backendSupportsFeature(backend: std.builtin.CompilerBackend, compt
         },
         .separate_thread => switch (backend) {
             .stage2_llvm => false,
-            // MLUGG TODO
             .stage2_c, .stage2_wasm => true,
+            // TODO: most self-hosted backends should be able to support this without too much work.
             else => false,
         },
     };