feat(runtime-core) Feed imported functions with vm::Ctx again.

… and look for the associated `vm::FuncCtx`. This way, we don't break
the rule: “all functions receive a vmctx pointer as first argument.”.

lib/clif-backend/src/code.rs

@@ -691,7 +691,9 @@ impl FuncEnvironment for FunctionEnvironment {
     }
 
     /// Generates a call IR with `callee` and `call_args` and inserts it at `pos`
-    /// TODO: add support for imported functions
+    ///
+    /// It's about generating code that calls a local or imported function; in
+    /// WebAssembly: `(call $foo)`.
     fn translate_call(
         &mut self,
         mut pos: FuncCursor,
@@ -771,14 +773,23 @@ impl FuncEnvironment for FunctionEnvironment {
                         readonly: true,
                     });
 
+                let imported_func_ctx_vmctx_addr =
+                    pos.func.create_global_value(ir::GlobalValueData::Load {
+                        base: imported_func_ctx_addr,
+                        offset: (0 as i32).into(),
+                        global_type: ptr_type,
+                        readonly: true,
+                    });
+
                 let imported_func_addr = pos.ins().global_value(ptr_type, imported_func_addr);
-                let imported_func_ctx_addr =
+                let imported_func_ctx_vmctx_addr = pos
-                    pos.ins().global_value(ptr_type, imported_func_ctx_addr);
+                    .ins()
+                    .global_value(ptr_type, imported_func_ctx_vmctx_addr);
 
                 let sig_ref = pos.func.dfg.ext_funcs[callee].signature;
 
                 let mut args = Vec::with_capacity(call_args.len() + 1);
-                args.push(imported_func_ctx_addr);
+                args.push(imported_func_ctx_vmctx_addr);
                 args.extend(call_args.iter().cloned());
 
                 Ok(pos

lib/runtime-core/src/typed_func.rs

@@ -502,7 +502,7 @@ macro_rules! impl_traits {
                 // able to unwind through this function.
                 #[cfg_attr(nightly, unwind(allowed))]
                 extern fn wrap<$( $x, )* Rets, Trap, FN>(
-                    func_ctx: &mut vm::FuncCtx $( , $x: <$x as WasmExternType>::Native )*
+                    vmctx: &vm::Ctx $( , $x: <$x as WasmExternType>::Native )*
                 ) -> Rets::CStruct
                 where
                     $( $x: WasmExternType, )*
@@ -510,6 +510,25 @@ macro_rules! impl_traits {
                     Trap: TrapEarly<Rets>,
                     FN: Fn(&mut vm::Ctx, $( $x, )*) -> Trap,
                 {
+                    // Get the pointer to this `wrap` function.
+                    let self_pointer = wrap::<$( $x, )* Rets, Trap, FN> as *const vm::Func;
+
+                    // Get the collection of imported functions.
+                    let vm_imported_functions = unsafe { &(*vmctx.import_backing).vm_functions };
+
+                    // Retrieve the `vm::FuncCtx`.
+                    let mut func_ctx: NonNull<vm::FuncCtx> = vm_imported_functions
+                        .iter()
+                        .find_map(|(_, imported_func)| {
+                            if imported_func.func == self_pointer {
+                                Some(imported_func.func_ctx)
+                            } else {
+                                None
+                            }
+                        })
+                        .expect("Import backing is not well-formed, cannot find `func_ctx`.");
+                    let func_ctx = unsafe { func_ctx.as_mut() };
+
                     // Extract `vm::Ctx` from `vm::FuncCtx`. The
                     // pointer is always non-null.
                     let vmctx = unsafe { func_ctx.vmctx.as_mut() };
@@ -598,7 +617,7 @@ macro_rules! impl_traits {
                 // able to unwind through this function.
                 #[cfg_attr(nightly, unwind(allowed))]
                 extern fn wrap<$( $x, )* Rets, Trap, FN>(
-                    func_ctx: &mut vm::FuncCtx $( , $x: <$x as WasmExternType>::Native )*
+                    vmctx: &vm::Ctx $( , $x: <$x as WasmExternType>::Native )*
                 ) -> Rets::CStruct
                 where
                     $( $x: WasmExternType, )*
@@ -606,6 +625,25 @@ macro_rules! impl_traits {
                     Trap: TrapEarly<Rets>,
                     FN: Fn($( $x, )*) -> Trap,
                 {
+                    // Get the pointer to this `wrap` function.
+                    let self_pointer = wrap::<$( $x, )* Rets, Trap, FN> as *const vm::Func;
+
+                    // Get the collection of imported functions.
+                    let vm_imported_functions = unsafe { &(*vmctx.import_backing).vm_functions };
+
+                    // Retrieve the `vm::FuncCtx`.
+                    let mut func_ctx: NonNull<vm::FuncCtx> = vm_imported_functions
+                        .iter()
+                        .find_map(|(_, imported_func)| {
+                            if imported_func.func == self_pointer {
+                                Some(imported_func.func_ctx)
+                            } else {
+                                None
+                            }
+                        })
+                        .expect("Import backing is not well-formed, cannot find `func_ctx`.");
+                    let func_ctx = unsafe { func_ctx.as_mut() };
+
                     // Extract `vm::Ctx` from `vm::FuncCtx`. The
                     // pointer is always non-null.
                     let vmctx = unsafe { func_ctx.vmctx.as_mut() };