Try #338:

lib/clif-backend/src/signal/mod.rs

@@ -2,12 +2,13 @@ use crate::relocation::{TrapData, TrapSink};
 use crate::trampoline::Trampolines;
 use hashbrown::HashSet;
 use libc::c_void;
-use std::{any::Any, cell::Cell, sync::Arc};
+use std::{any::Any, cell::Cell, ptr::NonNull, sync::Arc};
 use wasmer_runtime_core::{
     backend::{ProtectedCaller, Token, UserTrapper},
     error::RuntimeResult,
     export::Context,
     module::{ExportIndex, ModuleInfo, ModuleInner},
+    typed_func::{Wasm, WasmTrapInfo},
     types::{FuncIndex, FuncSig, LocalOrImport, SigIndex, Type, Value},
     vm::{self, ImportBacking},
 };
@@ -148,6 +149,46 @@ impl ProtectedCaller for Caller {
             .collect())
     }
 
+    fn get_wasm_trampoline(&self, module: &ModuleInner, sig_index: SigIndex) -> Option<Wasm> {
+        unsafe extern "C" fn invoke(
+            trampoline: unsafe extern "C" fn(*mut vm::Ctx, NonNull<vm::Func>, *const u64, *mut u64),
+            ctx: *mut vm::Ctx,
+            func: NonNull<vm::Func>,
+            args: *const u64,
+            rets: *mut u64,
+            trap_info: *mut WasmTrapInfo,
+            invoke_env: Option<NonNull<c_void>>,
+        ) -> bool {
+            let handler_data = &*invoke_env.unwrap().cast().as_ptr();
+
+            #[cfg(not(target_os = "windows"))]
+            let res = call_protected(handler_data, || unsafe {
+                // Leap of faith.
+                trampoline(ctx, func, args, rets);
+            })
+            .is_ok();
+
+            // the trampoline is called from C on windows
+            #[cfg(target_os = "windows")]
+            let res = call_protected(handler_data, trampoline, ctx, func, args, rets).is_ok();
+
+            res
+        }
+
+        let trampoline = self
+            .trampolines
+            .lookup(sig_index)
+            .expect("that trampoline doesn't exist");
+
+        Some(unsafe {
+            Wasm::from_raw_parts(
+                trampoline,
+                invoke,
+                Some(NonNull::from(&self.handler_data).cast()),
+            )
+        })
+    }
+
     fn get_early_trapper(&self) -> Box<dyn UserTrapper> {
         Box::new(Trapper)
     }
@@ -157,7 +198,7 @@ fn get_func_from_index<'a>(
     module: &'a ModuleInner,
     import_backing: &ImportBacking,
     func_index: FuncIndex,
-) -> (*const vm::Func, Context, &'a FuncSig, SigIndex) {
+) -> (NonNull<vm::Func>, Context, &'a FuncSig, SigIndex) {
     let sig_index = *module
         .info
         .func_assoc
@@ -170,14 +211,13 @@ fn get_func_from_index<'a>(
                 .func_resolver
                 .get(&module, local_func_index)
                 .expect("broken invariant, func resolver not synced with module.exports")
-                .cast()
-                .as_ptr() as *const _,
+                .cast(),
             Context::Internal,
         ),
         LocalOrImport::Import(imported_func_index) => {
             let imported_func = import_backing.imported_func(imported_func_index);
             (
-                imported_func.func as *const _,
+                NonNull::new(imported_func.func as *mut _).unwrap(),
                 Context::External(imported_func.vmctx),
             )
         }

lib/clif-backend/src/signal/windows.rs

@@ -3,7 +3,7 @@ use crate::signal::HandlerData;
 use crate::trampoline::Trampoline;
 use std::cell::Cell;
 use std::ffi::c_void;
-use std::ptr;
+use std::ptr::{self, NonNull};
 use wasmer_runtime_core::error::{RuntimeError, RuntimeResult};
 use wasmer_runtime_core::vm::Ctx;
 use wasmer_runtime_core::vm::Func;
@@ -25,7 +25,7 @@ pub fn call_protected(
     handler_data: &HandlerData,
     trampoline: Trampoline,
     ctx: *mut Ctx,
-    func: *const Func,
+    func: NonNull<Func>,
     param_vec: *const u64,
     return_vec: *mut u64,
 ) -> RuntimeResult<()> {

lib/clif-backend/src/trampoline.rs

@@ -7,7 +7,7 @@ use cranelift_codegen::{
 };
 use hashbrown::HashMap;
 use std::ffi::c_void;
-use std::{iter, mem};
+use std::{iter, mem, ptr::NonNull};
 use wasmer_runtime_core::{
     backend::sys::{Memory, Protect},
     module::{ExportIndex, ModuleInfo},
@@ -23,8 +23,7 @@ impl RelocSink for NullRelocSink {
     fn reloc_jt(&mut self, _: u32, _: Reloc, _: ir::JumpTable) {}
 }
 
-pub type Trampoline =
-    unsafe extern "C" fn(*mut vm::Ctx, *const vm::Func, *const u64, *mut u64) -> c_void;
+pub type Trampoline = unsafe extern "C" fn(*mut vm::Ctx, NonNull<vm::Func>, *const u64, *mut u64);
 
 pub struct Trampolines {
     memory: Memory,

lib/dynasm-backend/src/codegen_x64.rs

@@ -18,6 +18,7 @@ use wasmer_runtime_core::{
     memory::MemoryType,
     module::{ModuleInfo, ModuleInner},
     structures::{Map, TypedIndex},
+    typed_func::Wasm,
     types::{
         FuncIndex, FuncSig, ImportedMemoryIndex, LocalFuncIndex, LocalGlobalIndex,
         LocalMemoryIndex, LocalOrImport, MemoryIndex, SigIndex, Type, Value,
@@ -459,6 +460,10 @@ impl ProtectedCaller for X64ExecutionContext {
         })
     }
 
+    fn get_wasm_trampoline(&self, _module: &ModuleInner, _sig_index: SigIndex) -> Option<Wasm> {
+        unimplemented!()
+    }
+
     fn get_early_trapper(&self) -> Box<dyn UserTrapper> {
         pub struct Trapper;
 

lib/emscripten/src/varargs.rs

@@ -20,4 +20,11 @@ impl VarArgs {
 
 unsafe impl WasmExternType for VarArgs {
     const TYPE: Type = Type::I32;
+
+    fn to_bits(self) -> u64 {
+        self.pointer as u64
+    }
+    fn from_bits(n: u64) -> Self {
+        Self { pointer: n as u32 }
+    }
 }