Support imported functions

lib/clif-backend/src/codegen.rs

@@ -1,18 +1,4 @@
-use wasmer_runtime::{
+use crate::resolver::FuncResolverBuilder;
-    FuncResolver,
-    LinearMemory,
-    ModuleInner as WasmerModule,
-    SigRegistry,
-    module::{DataInitializer, Export, ImportName, TableInitializer},
-    types::{
-        ElementType as WasmerElementType, FuncIndex as WasmerFuncIndex, FuncSig as WasmerSignature,
-        Global as WasmerGlobal, GlobalDesc as WasmerGlobalDesc, GlobalIndex as WasmerGlobalIndex,
-        Initializer as WasmerInitializer, Map, MapIndex, Memory as WasmerMemory,
-        MemoryIndex as WasmerMemoryIndex, SigIndex as WasmerSignatureIndex, Table as WasmerTable,
-        TableIndex as WasmerTableIndex, Type as WasmerType,
-    },
-    vm::Ctx as WasmerVMContext,
-};
 use cranelift_codegen::cursor::FuncCursor;
 use cranelift_codegen::ir::immediates::{Offset32, Uimm64};
 use cranelift_codegen::ir::types::{self, *};
@@ -29,7 +15,18 @@ use cranelift_wasm::{
 };
 use hashbrown::HashMap;
 use target_lexicon;
-use crate::resolver::{FuncResolverBuilder};
+use wasmer_runtime::{
+    module::{DataInitializer, Export, ImportName, TableInitializer},
+    types::{
+        ElementType as WasmerElementType, FuncIndex as WasmerFuncIndex, FuncSig as WasmerSignature,
+        Global as WasmerGlobal, GlobalDesc as WasmerGlobalDesc, GlobalIndex as WasmerGlobalIndex,
+        Initializer as WasmerInitializer, Map, MapIndex, Memory as WasmerMemory,
+        MemoryIndex as WasmerMemoryIndex, SigIndex as WasmerSignatureIndex, Table as WasmerTable,
+        TableIndex as WasmerTableIndex, Type as WasmerType,
+    },
+    vm::{self, Ctx as WasmerVMContext},
+    LinearMemory, ModuleInner as WasmerModule, SigRegistry,
+};
 
 /// The converter namespace contains functions for converting a Cranelift module
 /// to a Wasmer module.
@@ -72,8 +69,17 @@ pub mod converter {
             func_assoc.push(WasmerSignatureIndex::new(signature_index.index()));
         }
 
-        let function_bodies: Vec<_> = cranelift_module.function_bodies.into_iter().map(|(_, v)| v.clone()).collect();
+        let function_bodies: Vec<_> = cranelift_module
-        let func_resolver_builder = FuncResolverBuilder::new(&*crate::get_isa(), function_bodies).unwrap();
+            .function_bodies
+            .into_iter()
+            .map(|(_, v)| v.clone())
+            .collect();
+        let func_resolver_builder = FuncResolverBuilder::new(
+            &*crate::get_isa(),
+            function_bodies,
+            cranelift_module.imported_functions.len(),
+        )
+        .unwrap();
 
         // Create func_resolver.
         let func_resolver = Box::new(func_resolver_builder.finalize().unwrap());
@@ -217,9 +223,6 @@ pub struct CraneliftModule {
     /// The external function declaration for implementing wasm's `grow_memory`.
     pub grow_memory_extfunc: Option<FuncRef>,
 
-    /// A function that takes a Wasmer module and resolves a function index to a vm::Func.
-    pub func_resolver: Option<Box<dyn FuncResolver>>,
-
     // An array holding information about the wasm instance memories.
     pub memories: Vec<Memory>,
 
@@ -271,7 +274,6 @@ impl CraneliftModule {
             memories_base: None,
             current_memory_extfunc: None,
             grow_memory_extfunc: None,
-            func_resolver: None,
             memories: Vec::new(),
             globals: Vec::new(),
             tables: Vec::new(),
@@ -286,8 +288,7 @@ impl CraneliftModule {
         };
 
         // Translate wasm to cranelift IR.
-        translate_module(&buffer_source, &mut cranelift_module)
+        translate_module(&buffer_source, &mut cranelift_module).map_err(|e| e.to_string())?;
-            .map_err(|e| e.to_string())?;
 
         // Return translated module.
         Ok(cranelift_module)
@@ -560,12 +561,68 @@ impl<'environment> FuncEnvironmentTrait for FuncEnvironment<'environment> {
     fn translate_call(
         &mut self,
         mut pos: FuncCursor,
-        _callee_index: FuncIndex,
+        callee_index: FuncIndex,
         callee: ir::FuncRef,
         call_args: &[ir::Value],
     ) -> WasmResult<ir::Inst> {
         // Insert call instructions for `callee`.
-        Ok(pos.ins().call(callee, call_args))
+
+        if callee_index.index() < self.module.imported_functions.len() {
+            // this is an imported function
+            let vmctx = pos.func.create_global_value(ir::GlobalValueData::VMContext);
+
+            let imported_funcs = pos.func.create_global_value(ir::GlobalValueData::Load {
+                base: vmctx,
+                offset: (WasmerVMContext::offset_imported_funcs() as i32).into(),
+                global_type: self.pointer_type(),
+                readonly: true,
+            });
+
+            let imported_func_struct_addr =
+                pos.func.create_global_value(ir::GlobalValueData::IAddImm {
+                    base: imported_funcs,
+                    offset: (callee_index.index() as i64 * vm::ImportedFunc::size() as i64).into(),
+                    global_type: self.pointer_type(),
+                });
+
+            let imported_func_addr = pos.func.create_global_value(ir::GlobalValueData::Load {
+                base: imported_func_struct_addr,
+                offset: (vm::ImportedFunc::offset_func() as i32).into(),
+                global_type: self.pointer_type(),
+                readonly: true,
+            });
+
+            let imported_func_addr = pos
+                .ins()
+                .global_value(self.pointer_type(), imported_func_addr);
+
+            let sig_ref = pos.func.dfg.ext_funcs[callee].signature;
+
+            let vmctx = pos
+                .func
+                .special_param(ir::ArgumentPurpose::VMContext)
+                .expect("missing vmctx parameter");
+
+            let mut args = Vec::with_capacity(call_args.len() + 1);
+            args.extend(call_args.iter().cloned());
+            args.push(vmctx);
+
+            Ok(pos
+                .ins()
+                .call_indirect(sig_ref, imported_func_addr, &args[..]))
+        } else {
+            // this is an internal function
+            let vmctx = pos
+                .func
+                .special_param(ir::ArgumentPurpose::VMContext)
+                .expect("missing vmctx parameter");
+
+            let mut args = Vec::with_capacity(call_args.len() + 1);
+            args.extend(call_args.iter().cloned());
+            args.push(vmctx);
+
+            Ok(pos.ins().call(callee, &args[..]))
+        }
     }
 
     /// Generates code corresponding to wasm `memory.grow`.

lib/clif-backend/src/lib.rs

@@ -3,13 +3,16 @@ mod libcalls;
 mod relocation;
 mod resolver;
 
-use wasmer_runtime::{Compiler, Module};
+use cranelift_codegen::{
-use cranelift_codegen::{settings::{self, Configurable}, isa};
+    isa,
+    settings::{self, Configurable},
+};
 use target_lexicon::Triple;
+use wasmer_runtime::{Compiler, Module};
 use wasmparser::{self, WasmDecoder};
 
-use self::codegen::CraneliftModule;
 use self::codegen::converter;
+use self::codegen::CraneliftModule;
 
 pub struct CraneliftCompiler {}
 
@@ -59,10 +62,7 @@ fn validate(bytes: &[u8]) -> Result<(), String> {
         match *state {
             wasmparser::ParserState::EndWasm => return Ok(()),
             wasmparser::ParserState::Error(err) => {
-                return Err(format!(
+                return Err(format!("Validation error: {}", err.message));
-                    "Validation error: {}",
-                    err.message
-                ));
             }
             _ => (),
         }

lib/clif-backend/src/resolver.rs

@@ -1,19 +1,14 @@
-use cranelift_codegen::{
+use crate::libcalls;
-    ir,
+use crate::relocation::{Reloc, RelocSink, Relocation, RelocationType, TrapSink};
-    isa,
+use cranelift_codegen::{ir, isa, Context};
-    Context,
+use std::mem;
-};
+use std::ptr::{write_unaligned, NonNull};
 use wasmer_runtime::{
     self,
-    types::{Map, MapIndex, FuncIndex},
     mmap::{Mmap, Protect},
-    vm,
+    types::{FuncIndex, Map, MapIndex},
-    vmcalls,
+    vm, vmcalls,
 };
-use crate::relocation::{Reloc, RelocSink, Relocation, RelocationType, TrapSink};
-use crate::libcalls;
-use std::ptr::{write_unaligned, NonNull};
-use std::mem;
 
 #[allow(dead_code)]
 pub struct FuncResolverBuilder {
@@ -23,7 +18,11 @@ pub struct FuncResolverBuilder {
 }
 
 impl FuncResolverBuilder {
-    pub fn new(isa: &isa::TargetIsa, function_bodies: Vec<ir::Function>) -> Result<Self, String> {
+    pub fn new(
+        isa: &isa::TargetIsa,
+        function_bodies: Vec<ir::Function>,
+        num_imported_funcs: usize,
+    ) -> Result<Self, String> {
         let mut compiled_functions: Vec<Vec<u8>> = Vec::with_capacity(function_bodies.len());
         let mut relocations = Map::with_capacity(function_bodies.len());
         let mut trap_sinks = Map::with_capacity(function_bodies.len());
@@ -37,11 +36,8 @@ impl FuncResolverBuilder {
             let mut reloc_sink = RelocSink::new();
             let mut trap_sink = TrapSink::new();
 
-            ctx
+            ctx.compile_and_emit(isa, &mut code_buf, &mut reloc_sink, &mut trap_sink)
-                .compile_and_emit(isa, &mut code_buf, &mut reloc_sink, &mut trap_sink)
+                .map_err(|e| format!("compile error: {}", e.to_string()))?;
-                .map_err(|e| {
-                    format!("compile error: {}", e.to_string())
-                })?;
             ctx.clear();
             // Round up each function's size to pointer alignment.
             total_size += round_up(code_buf.len(), mem::size_of::<usize>());
@@ -62,7 +58,8 @@ impl FuncResolverBuilder {
         for compiled in compiled_functions.iter() {
             let new_end = previous_end + round_up(compiled.len(), mem::size_of::<usize>());
             unsafe {
-                memory.as_slice_mut()[previous_end..previous_end + compiled.len()].copy_from_slice(&compiled[..]);
+                memory.as_slice_mut()[previous_end..previous_end + compiled.len()]
+                    .copy_from_slice(&compiled[..]);
             }
             map.push(previous_end);
             previous_end = new_end;
@@ -70,6 +67,7 @@ impl FuncResolverBuilder {
 
         Ok(Self {
             resolver: FuncResolver {
+                num_imported_funcs,
                 map,
                 memory,
             },
@@ -86,7 +84,10 @@ impl FuncResolverBuilder {
                         // This will always be an internal function
                         // because imported functions are not
                         // called in this way.
-                        self.resolver.lookup(FuncIndex::new(func_index as _)).unwrap().as_ptr() as isize
+                        self.resolver
+                            .lookup(FuncIndex::new(func_index as _))
+                            .unwrap()
+                            .as_ptr() as isize
                     }
                     RelocationType::CurrentMemory => vmcalls::memory_size as isize,
                     RelocationType::GrowMemory => vmcalls::memory_grow_static as isize,
@@ -135,7 +136,9 @@ impl FuncResolverBuilder {
         }
 
         unsafe {
-            self.resolver.memory.protect(0..self.resolver.memory.size(), Protect::ReadExec)?;
+            self.resolver
+                .memory
+                .protect(0..self.resolver.memory.size(), Protect::ReadExec)?;
         }
 
         Ok(self.resolver)
@@ -144,16 +147,17 @@ impl FuncResolverBuilder {
 
 /// Resolves a function index to a function address.
 pub struct FuncResolver {
+    num_imported_funcs: usize,
     map: Map<FuncIndex, usize>,
     memory: Mmap,
 }
 
 impl FuncResolver {
     fn lookup(&self, index: FuncIndex) -> Option<NonNull<vm::Func>> {
-        let offset = *self.map.get(index)?;
+        let offset = *self
-        let ptr = unsafe {
+            .map
-            self.memory.as_ptr().add(offset)
+            .get(FuncIndex::new(index.index() - self.num_imported_funcs))?;
-        };
+        let ptr = unsafe { self.memory.as_ptr().add(offset) };
 
         NonNull::new(ptr).map(|nonnull| nonnull.cast())
     }

lib/runtime/examples/simple/main.rs

@@ -1,13 +1,38 @@
-use wasmer_runtime as runtime;
 use wasmer_clif_backend::CraneliftCompiler;
+use wasmer_runtime::{
+    self as runtime,
+    types::{FuncSig, Type, Value},
+    vm, Import, Imports,
+};
 
 static EXAMPLE_WASM: &'static [u8] = include_bytes!("simple.wasm");
 
-fn main() {
+fn main() -> Result<(), String> {
-    let compiler = CraneliftCompiler::new();
+    let module = runtime::compile(EXAMPLE_WASM, &CraneliftCompiler::new())?;
-    let module = runtime::compile(EXAMPLE_WASM, &compiler).unwrap();
+
-    let imports = runtime::Imports::new();
+    let mut imports = Imports::new();
-    let mut instance = module.instantiate(&imports).unwrap();
+    imports.add(
-    let ret = instance.call("main", &[runtime::types::Value::I32(42)]);
+        "env".to_string(),
+        "print_num".to_string(),
+        Import::Func(
+            print_num as _,
+            FuncSig {
+                params: vec![Type::I32],
+                returns: vec![Type::I32],
+            },
+        ),
+    );
+
+    let mut instance = module.instantiate(&imports)?;
+
+    let ret = instance.call("main", &[Value::I32(42)])?;
+
     println!("ret: {:?}", ret);
+
+    Ok(())
+}
+
+extern "C" fn print_num(n: i32, _vmctx: *mut vm::Ctx) -> i32 {
+    println!("print_num({})", n);
+    n + 1
 }

lib/runtime/src/backing.rs

@@ -108,7 +108,6 @@ impl LocalBacking {
             match table.elements {
                 TableElements::Anyfunc(ref mut elements) => {
                     for (i, &func_index) in init.elements.iter().enumerate() {
-
                         let sig_index = module.func_assoc[func_index];
                         let vm_sig_id = vm::SigId(sig_index.index() as u32);
 
@@ -263,7 +262,8 @@ impl ImportBacking {
             let sig_index = module.func_assoc[index];
             let expected_sig = module.sig_registry.lookup_func_sig(sig_index);
             let import = imports.get(mod_name, item_name);
-            if let Some(&Import::Func(func, ref signature)) = import {
+            match import {
+                Some(&Import::Func(func, ref signature)) => {
                     if expected_sig == signature {
                         functions.push(vm::ImportedFunc {
                             func,
@@ -275,8 +275,16 @@ impl ImportBacking {
                             mod_name, item_name
                         ));
                     }
-            } else {
+                }
-                return Err(format!("incorrect type for {:?}:{:?}", mod_name, item_name));
+                Some(_) => {
+                    return Err(format!(
+                        "incorrect import type for {}:{}",
+                        mod_name, item_name
+                    ));
+                }
+                None => {
+                    return Err(format!("import not found: {}:{}", mod_name, item_name));
+                }
             }
         }
 
@@ -293,15 +301,16 @@ impl ImportBacking {
         ) in &module.imported_globals
         {
             let import = imports.get(mod_name, item_name);
-            if let Some(&Import::Global(val)) = import {
+            match import {
+                Some(Import::Global(val)) => {
                     if val.ty() == global_desc.ty {
                         globals.push(vm::ImportedGlobal {
                             global: vm::LocalGlobal {
                                 data: match val {
-                                Value::I32(n) => n as u64,
+                                    Value::I32(n) => *n as u64,
-                                Value::I64(n) => n as u64,
+                                    Value::I64(n) => *n as u64,
-                                Value::F32(n) => n as u64,
+                                    Value::F32(n) => *n as u64,
-                                Value::F64(n) => n,
+                                    Value::F64(n) => *n,
                                 },
                             },
                         });
@@ -311,8 +320,16 @@ impl ImportBacking {
                             mod_name, item_name
                         ));
                     }
-            } else {
+                }
-                return Err(format!("incorrect type for {:?}:{:?}", mod_name, item_name));
+                Some(_) => {
+                    return Err(format!(
+                        "incorrect import type for {}:{}",
+                        mod_name, item_name
+                    ));
+                }
+                None => {
+                    return Err(format!("import not found: {}:{}", mod_name, item_name));
+                }
             }
         }
 

lib/runtime/src/instance.rs

@@ -19,7 +19,10 @@ pub struct Instance {
 }
 
 impl Instance {
-    pub(crate) fn new(module: Module, imports: &dyn ImportResolver) -> Result<Box<Instance>, String> {
+    pub(crate) fn new(
+        module: Module,
+        imports: &dyn ImportResolver,
+    ) -> Result<Box<Instance>, String> {
         let import_backing = ImportBacking::new(&module, imports)?;
         let backing = LocalBacking::new(&module, &import_backing);
 
@@ -85,10 +88,7 @@ impl Instance {
 
         // the vmctx will be located at the same place on the stack the entire time that this
         // wasm function is running.
-        let mut vmctx = vm::Ctx::new(
+        let mut vmctx = vm::Ctx::new(&mut self.backing, &mut self.import_backing);
-            &mut self.backing,
-            &mut self.import_backing,
-        );
         let vmctx_ptr = &mut vmctx as *mut vm::Ctx;
 
         let libffi_args: Vec<_> = args
@@ -102,15 +102,19 @@ impl Instance {
             .chain(iter::once(libffi_arg(&vmctx_ptr)))
             .collect();
 
-        let func_ptr = CodePtr::from_ptr(self.module
+        let func_ptr = CodePtr::from_ptr(
+            self.module
                 .func_resolver
                 .get(&self.module, func_index)
                 .expect("broken invariant, func resolver not synced with module.exports")
                 .cast()
-                .as_ptr());
+                .as_ptr(),
+        );
 
         call_protected(|| {
-            self.module.sig_registry.lookup_func_sig(sig_index)
+            self.module
+                .sig_registry
+                .lookup_func_sig(sig_index)
                 .returns
                 .first()
                 .map(|ty| match ty {

lib/runtime/src/lib.rs

@@ -4,26 +4,23 @@ mod backend;
 mod backing;
 mod instance;
 mod memory;
-mod sig_registry;
-mod table;
-mod recovery;
-mod sighandler;
 pub mod mmap;
 pub mod module;
+mod recovery;
+mod sig_registry;
+mod sighandler;
+mod table;
 pub mod types;
 pub mod vm;
 pub mod vmcalls;
 
 pub use self::backend::{Compiler, FuncResolver};
 pub use self::instance::{Import, ImportResolver, Imports, Instance};
+pub use self::memory::LinearMemory;
 pub use self::module::{Module, ModuleInner};
 pub use self::sig_registry::SigRegistry;
-pub use self::memory::LinearMemory;
 
 /// Compile a webassembly module using the provided compiler.
-pub fn compile(
+pub fn compile(wasm: &[u8], compiler: &dyn Compiler) -> Result<Module, String> {
-    wasm: &[u8],
-    compiler: &dyn Compiler,
-) -> Result<Module, String> {
     compiler.compile(wasm)
 }

lib/runtime/src/memory.rs

@@ -5,7 +5,11 @@
 //! mutable from both Rust and WebAssembly.
 use std::ops::{Deref, DerefMut};
 
-use crate::{types::Memory, vm::LocalMemory, mmap::{Mmap, Protect}};
+use crate::{
+    mmap::{Mmap, Protect},
+    types::Memory,
+    vm::LocalMemory,
+};
 
 /// A linear memory instance.
 #[derive(Debug)]
@@ -69,7 +73,10 @@ impl LinearMemory {
         // map initial pages as readwrite since the inital mmap is mapped as not accessible.
         if initial_pages != 0 {
             unsafe {
-                mmap.protect(0..(initial_pages as usize * Self::PAGE_SIZE as usize), Protect::ReadWrite)
+                mmap.protect(
+                    0..(initial_pages as usize * Self::PAGE_SIZE as usize),
+                    Protect::ReadWrite,
+                )
                 .expect("unable to make memory accessible");
             }
         }
@@ -191,7 +198,9 @@ impl LinearMemory {
         let new_bytes = (new_pages * Self::PAGE_SIZE) as usize;
 
         unsafe {
-            self.mmap.protect(prev_bytes..new_bytes, Protect::ReadWrite).ok()?;
+            self.mmap
+                .protect(prev_bytes..new_bytes, Protect::ReadWrite)
+                .ok()?;
         }
 
         self.current = new_pages;
@@ -210,16 +219,12 @@ impl PartialEq for LinearMemory {
 impl Deref for LinearMemory {
     type Target = [u8];
     fn deref(&self) -> &[u8] {
-        unsafe {
+        unsafe { self.mmap.as_slice() }
-            self.mmap.as_slice()
-        }
     }
 }
 
 impl DerefMut for LinearMemory {
     fn deref_mut(&mut self) -> &mut [u8] {
-        unsafe {
+        unsafe { self.mmap.as_slice_mut() }
-            self.mmap.as_slice_mut()
-        }
     }
 }

lib/runtime/src/mmap.rs

@@ -1,8 +1,8 @@
-use std::{slice, ptr};
+use errno;
-use std::ops::Range;
 use nix::libc;
 use page_size;
-use errno;
+use std::ops::Range;
+use std::{ptr, slice};
 
 #[derive(Debug)]
 pub struct Mmap {
@@ -44,7 +44,9 @@ impl Mmap {
 
     pub unsafe fn protect(&mut self, range: Range<usize>, protect: Protect) -> Result<(), String> {
         let page_size = page_size::get();
-        let start = self.ptr.add(round_down_to_page_size(range.start, page_size));
+        let start = self
+            .ptr
+            .add(round_down_to_page_size(range.start, page_size));
         let size = round_up_to_page_size(range.end - range.start, page_size);
         assert!(size <= self.size);
 

lib/runtime/src/module.rs

@@ -1,16 +1,15 @@
 use crate::{
     backend::FuncResolver,
-    types::{
-        FuncIndex, Global, GlobalDesc, GlobalIndex, Map, MapIndex, Memory, MemoryIndex,
-        SigIndex, Table, TableIndex,
-    },
     sig_registry::SigRegistry,
-    ImportResolver,
+    types::{
-    Instance,
+        FuncIndex, Global, GlobalDesc, GlobalIndex, Map, MapIndex, Memory, MemoryIndex, SigIndex,
+        Table, TableIndex,
+    },
+    ImportResolver, Instance,
 };
-use std::sync::Arc;
-use std::ops::Deref;
 use hashbrown::HashMap;
+use std::ops::Deref;
+use std::sync::Arc;
 
 /// This is used to instantiate a new webassembly module.
 pub struct ModuleInner {
@@ -62,7 +61,6 @@ impl Deref for Module {
     }
 }
 
-
 #[derive(Debug, Clone)]
 pub struct ImportName {
     pub module: String,

lib/runtime/src/sig_registry.rs

@@ -1,5 +1,5 @@
 use crate::{
-    types::{FuncSig, Map, SigIndex, MapIndex},
+    types::{FuncSig, Map, MapIndex, SigIndex},
     vm,
 };
 use hashbrown::HashMap;
@@ -20,9 +20,9 @@ impl SigRegistry {
     pub fn register(&mut self, func_sig: FuncSig) -> SigIndex {
         let func_table = &mut self.func_table;
         let sig_assoc = &mut self.sig_assoc;
-        *func_table.entry(func_sig.clone()).or_insert_with(|| {
+        *func_table
-            sig_assoc.push(func_sig)
+            .entry(func_sig.clone())
-        })
+            .or_insert_with(|| sig_assoc.push(func_sig))
     }
 
     pub fn lookup_func_sig(&self, sig_index: SigIndex) -> &FuncSig {
@@ -30,7 +30,11 @@ impl SigRegistry {
     }
 
     pub(crate) fn into_vm_sigid(&self) -> Box<[vm::SigId]> {
-        let v: Vec<_> = self.sig_assoc.iter().map(|(sig_index, _)| vm::SigId(sig_index.index() as u32)).collect();
+        let v: Vec<_> = self
+            .sig_assoc
+            .iter()
+            .map(|(sig_index, _)| vm::SigId(sig_index.index() as u32))
+            .collect();
         v.into_boxed_slice()
     }
 }

lib/runtime/src/types.rs

@@ -17,7 +17,7 @@ pub enum Type {
     F64,
 }
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Value {
     /// The `i32` type.
     I32(i32),
@@ -83,7 +83,7 @@ pub struct Table {
 /// A global value initializer.
 /// Overtime, this will be able to represent more and more
 /// complex expressions.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Initializer {
     /// Corresponds to a `const.*` instruction.
     Const(Value),
@@ -98,7 +98,7 @@ pub struct GlobalDesc {
 }
 
 /// A wasm global.
-#[derive(Debug, Clone, Copy)]
+#[derive(Debug, Clone)]
 pub struct Global {
     pub desc: GlobalDesc,
     pub init: Initializer,

lib/runtime/src/vm.rs

@@ -33,10 +33,7 @@ pub struct Ctx {
 }
 
 impl Ctx {
-    pub fn new(
+    pub fn new(local_backing: &mut LocalBacking, import_backing: &mut ImportBacking) -> Self {
-        local_backing: &mut LocalBacking,
-        import_backing: &mut ImportBacking,
-    ) -> Self {
         Self {
             memories: local_backing.vm_memories.as_mut_ptr(),
             tables: local_backing.vm_tables.as_mut_ptr(),
@@ -101,6 +98,10 @@ impl ImportedFunc {
     pub fn offset_func() -> u8 {
         0 * (mem::size_of::<usize>() as u8)
     }
+
+    pub fn size() -> u8 {
+        mem::size_of::<Self>() as u8
+    }
 }
 
 /// Definition of a table used by the VM. (obviously)