diff --git a/src/common/slice.rs b/src/common/slice.rs
index bb82a64c2..471b3b059 100644
--- a/src/common/slice.rs
+++ b/src/common/slice.rs
@@ -1,7 +1,5 @@
 use std::ops::{Index, IndexMut};
 use std::ptr::NonNull;
-use std::marker::PhantomData;
-use crate::runtime::types::MapIndex;
 
 #[derive(Copy, Clone, Debug)]
 #[repr(transparent)]
@@ -105,41 +103,4 @@ impl<'a, T> From<&'a [T]> for BoundedSlice<T> {
             len: slice.len(),
         }
     }
-}
-
-#[derive(Debug)]
-#[repr(transparent)]
-pub struct IndexedSlice<'a, T, I> {
-    ptr: NonNull<T>,
-    _phantom: PhantomData<I>,
-}
-
-impl<'a, T: 'a, I> IndexedSlice<T, I>
-where
-    I: MapIndex,
-{
-    pub(crate) fn new(ptr: *mut T) -> Self {
-        Self {
-            ptr: NonNull::new(ptr).unwrap(),
-            _phantom: PhantomData,
-        }
-    }
-
-    pub unsafe fn get(&self, index: I) -> &T {
-        let ptr = self.as_ptr();
-        &*ptr.add(index.index())
-    }
-
-    pub unsafe fn get_mut(&mut self, index: I) -> &mut T {
-        let ptr = self.as_mut_ptr();
-        &mut *ptr.add(index.index())
-    }
-
-    pub fn as_ptr(&self) -> *const T {
-        self.ptr.as_ptr()
-    }
-
-    pub fn as_mut_ptr(&mut self) -> *mut T {
-        self.ptr.as_ptr()
-    }
 }
\ No newline at end of file
diff --git a/src/runtime/backend.rs b/src/runtime/backend.rs
index c48f41415..5d227166c 100644
--- a/src/runtime/backend.rs
+++ b/src/runtime/backend.rs
@@ -1,5 +1,4 @@
-use crate::runtime::module::Module;
-use crate::runtime::types::FuncIndex;
+
 use crate::runtime::{
     vm,
     module::Module,
@@ -12,5 +11,5 @@ pub trait Compiler {
 }
 
 pub trait FuncResolver {
-    pub fn resolve(&self, index: FuncIndex) -> Option<*const vm::Func>;
+    fn resolve(&self, index: FuncIndex) -> Option<*const vm::Func>;
 }
\ No newline at end of file
diff --git a/src/runtime/backing.rs b/src/runtime/backing.rs
index dae840c6a..f6ffb8220 100644
--- a/src/runtime/backing.rs
+++ b/src/runtime/backing.rs
@@ -2,11 +2,10 @@ use crate::runtime::{
     vm,
     module::Module,
     table::TableBacking,
-    types::{Val, GlobalInit},
+    types::{Val, GlobalInit, MapIndex},
     memory::LinearMemory,
     instance::{Imports, Import},
 };
-use std::{ptr, mem};
 
 
 #[derive(Debug)]
@@ -14,9 +13,9 @@ pub struct LocalBacking {
     memories: Box<[LinearMemory]>,
     tables: Box<[TableBacking]>,
 
-    vm_memories: Box<[vm::LocalMemory]>,
-    vm_tables: Box<[vm::LocalTable]>,
-    vm_globals: Box<[vm::LocalGlobal]>,
+    pub vm_memories: Box<[vm::LocalMemory]>,
+    pub vm_tables: Box<[vm::LocalTable]>,
+    pub vm_globals: Box<[vm::LocalGlobal]>,
 }
 
 impl LocalBacking {
@@ -29,8 +28,8 @@ impl LocalBacking {
             memories,
             tables,
 
-            vm_memories: Self::finalize_memories(module, &mut memories[..], options),
-            vm_tables: Self::finalize_tables(module, &mut tables[..], options),
+            vm_memories: Self::finalize_memories(module, &mut memories[..]),
+            vm_tables: Self::finalize_tables(module, &mut tables[..]),
             vm_globals: Self::finalize_globals(module, imports, globals),
         }
     }
@@ -42,7 +41,7 @@ impl LocalBacking {
             // If we use emscripten, we set a fixed initial and maximum
             debug!(
                 "Instance - init memory ({}, {:?})",
-                memory.min, memory.max
+                mem.min, mem.max
             );
             // let memory = if options.abi == InstanceABI::Emscripten {
             //     // We use MAX_PAGES, so at the end the result is:
@@ -80,7 +79,7 @@ impl LocalBacking {
     fn generate_tables(module: &Module) -> Box<[TableBacking]> {
         let mut tables = Vec::with_capacity(module.tables.len());
 
-        for table in &module.tables {
+        for (_, table) in &module.tables {
             let table_backing = TableBacking::new(table);
             tables.push(table_backing);
         }
@@ -99,13 +98,13 @@ impl LocalBacking {
     }
 
     fn finalize_globals(module: &Module, imports: &ImportBacking, globals: Box<[vm::LocalGlobal]>) -> Box<[vm::LocalGlobal]> {
-        for (to, from) in globals.iter_mut().zip(module.globals.iter()) {
-            *to = match from.init {
+        for (to, (_, from)) in globals.iter_mut().zip(module.globals.into_iter()) {
+            to.data = match from.init {
                 GlobalInit::Val(Val::I32(x)) => x as u64,
                 GlobalInit::Val(Val::I64(x)) => x as u64,
                 GlobalInit::Val(Val::F32(x)) => x as u64,
                 GlobalInit::Val(Val::F64(x)) => x,
-                GlobalInit::GetGlobal(index) => unsafe { (*imports.globals[index.index()].global).data },
+                GlobalInit::GetGlobal(index) => unsafe { (imports.globals[index.index()].global).data },
             };
         }
 
@@ -182,10 +181,10 @@ impl LocalBacking {
 
 #[derive(Debug)]
 pub struct ImportBacking {
-    functions: Box<[vm::ImportedFunc]>,
-    memories: Box<[vm::ImportedMemory]>,
-    tables: Box<[vm::ImportedTable]>,
-    globals: Box<[vm::ImportedGlobal]>,
+    pub functions: Box<[vm::ImportedFunc]>,
+    pub memories: Box<[vm::ImportedMemory]>,
+    pub tables: Box<[vm::ImportedTable]>,
+    pub globals: Box<[vm::ImportedGlobal]>,
 }
 
 impl ImportBacking {
@@ -195,42 +194,43 @@ impl ImportBacking {
 
         let mut functions = Vec::with_capacity(module.imported_functions.len());
         for (index, (mod_name, item_name)) in &module.imported_functions {
-            let expected_sig = module.signatures[index];
+            let expected_sig_index = module.signature_assoc[index];
+            let expected_sig = module.signatures[expected_sig_index];
             let import = imports.get(mod_name, item_name);
-            if let Import::Func(func, signature) = import {
-                if expected_sig == signature {
+            if let Some(Import::Func(func, signature)) = import {
+                if &expected_sig == signature {
                     functions.push(vm::ImportedFunc {
-                        func,
-                        vmctx: ptr::null_mut(),
+                        func: *func,
+                        // vmctx: ptr::null_mut(),
                     });
                 } else {
-                    return Err(format!("unexpected signature for {}:{}", mod_name, item_name));
+                    return Err(format!("unexpected signature for {:?}:{:?}", mod_name, item_name));
                 }
             } else {
-                return Err(format!("incorrect type for {}:{}", mod_name, item_name));
+                return Err(format!("incorrect type for {:?}:{:?}", mod_name, item_name));
             }
         }
 
         let mut globals = Vec::with_capacity(module.imported_globals.len());
         for (_, ((mod_name, item_name), global_desc)) in &module.imported_globals {
             let import = imports.get(mod_name, item_name);
-            if let Import::Global(val) = import {
+            if let Some(Import::Global(val)) = import {
                 if val.ty() == global_desc.ty {
                     globals.push(vm::ImportedGlobal {
                         global: vm::LocalGlobal {
                             data: match val {
-                                Val::I32(n) => n as u64,
-                                Val::I64(n) => n as u64,
-                                Val::F32(n) => n as u64,
-                                Val::F64(n) => n,
+                                Val::I32(n) => *n as u64,
+                                Val::I64(n) => *n as u64,
+                                Val::F32(n) => *n as u64,
+                                Val::F64(n) => *n,
                             },
                         },
                     });
                 } else {
-                    return Err(format!("unexpected global type for {}:{}", mod_name, item_name));
+                    return Err(format!("unexpected global type for {:?}:{:?}", mod_name, item_name));
                 }
             } else {
-                return Err(format!("incorrect type for {}:{}", mod_name, item_name));
+                return Err(format!("incorrect type for {:?}:{:?}", mod_name, item_name));
             }
         }
 
diff --git a/src/runtime/instance.rs b/src/runtime/instance.rs
index aa6bb2ac2..4bb3b98f4 100644
--- a/src/runtime/instance.rs
+++ b/src/runtime/instance.rs
@@ -1,21 +1,24 @@
 use crate::runtime::{
     vm,
     backing::{LocalBacking, ImportBacking},
-    module::{ModuleName, ItemName},
-    types::{Val, Memory, Table, Global, FuncSig},
+    module::{Module, ModuleName, ItemName},
+    types::{Val, Memory, Table, FuncSig},
     table::TableBacking,
     memory::LinearMemory,
+    sig_registry::SigRegistry,
 };
 use std::sync::Arc;
-use hashbrown::{HashMap, Entry};
+use hashbrown::HashMap;
 
 pub struct Instance {
     pub vmctx: vm::Ctx,
 
     backing: LocalBacking,
-    imports: ImportBacking,
+    import_backing: ImportBacking,
 
     pub module: Arc<Module>,
+
+    pub sig_registry: SigRegistry,
 }
 
 impl Instance {
@@ -23,18 +26,21 @@ impl Instance {
         let mut import_backing = ImportBacking::new(&*module, imports)?;
         let mut backing = LocalBacking::new(&*module, &import_backing);
 
-        let vmctx = vm::Ctx::new(&mut backing, &mut imports);
+        let sig_registry = SigRegistry::new();
+
+        let vmctx = vm::Ctx::new(&mut backing, &mut import_backing, &sig_registry);
         
         Ok(Box::new(Instance {
             vmctx,
             backing,
             import_backing,
             module,
+            sig_registry,
         }))
     }
 }
 
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug)]
 pub enum Import {
     Func(*const vm::Func, FuncSig),
     Table(Arc<TableBacking>, Table),
@@ -54,10 +60,10 @@ impl Imports {
     }
 
     pub fn add(&mut self, module: ModuleName, name: ItemName, import: Import) {
-        self.map.entry(module).or_insert(HashMap::new()).insert(name, import)
+        self.map.entry(module).or_insert(HashMap::new()).insert(name, import);
     }
 
-    pub fn get(&self, module: ModuleName, name: ItemName) -> Option<&Import> {
-        self.map.get().and_then(|m| m.get(name))
+    pub fn get(&self, module: &[u8], name: &[u8]) -> Option<&Import> {
+        self.map.get(module).and_then(|m| m.get(name))
     }
 }
\ No newline at end of file
diff --git a/src/runtime/memory.rs b/src/runtime/memory.rs
index 8ccc0a51a..a09caa9f3 100644
--- a/src/runtime/memory.rs
+++ b/src/runtime/memory.rs
@@ -10,7 +10,7 @@ use std::slice;
 use crate::common::mmap::Mmap;
 use crate::runtime::{
     vm::LocalMemory,
-    types::{Memory, Map, FuncIndex},
+    types::Memory,
 };
 
 /// A linear memory instance.
@@ -62,7 +62,7 @@ impl LinearMemory {
             assert!(!mem.shared, "shared memories must have a maximum size.");
 
             (mem.min as usize * Self::PAGE_SIZE as usize, mem.min, 0, false)
-        }
+        };
 
         let mut mmap = Mmap::with_size(mmap_size).unwrap();
 
@@ -103,7 +103,7 @@ impl LinearMemory {
 
     /// Returns the maximum number of wasm pages allowed.
     pub fn maximum_size(&self) -> u32 {
-        self.maximum.unwrap_or(Self::MAX_PAGES)
+        self.max.unwrap_or(Self::MAX_PAGES)
     }
 
     pub fn into_vm_memory(&mut self) -> LocalMemory {
@@ -131,7 +131,7 @@ impl LinearMemory {
             None => return None,
         };
 
-        if let Some(val) = self.maximum {
+        if let Some(val) = self.max {
             if new_pages > val {
                 return None;
             }
@@ -147,7 +147,7 @@ impl LinearMemory {
 
         if new_bytes > self.mmap.len() - self.offset_guard_size {
             let mmap_size = new_bytes.checked_add(self.offset_guard_size)?;
-            let mut new_mmap = Mmap::with_size(request_bytes).ok()?;
+            let mut new_mmap = Mmap::with_size(mmap_size).ok()?;
 
             unsafe {
                 region::protect(
@@ -158,7 +158,7 @@ impl LinearMemory {
             }
 
             let copy_size = self.mmap.len() - self.offset_guard_size;
-            new_mmap.as_mut_slice()[..copy_size].copy_from_slice(self.mmap.as_slice()[..copy_size]);
+            new_mmap.as_mut_slice()[..copy_size].copy_from_slice(&self.mmap.as_slice()[..copy_size]);
 
             self.mmap = new_mmap;
         }
@@ -182,7 +182,7 @@ impl LinearMemory {
             None => return None,
         };
 
-        if let Some(val) = self.maximum {
+        if let Some(val) = self.max {
             if new_pages > val {
                 return None;
             }
@@ -213,7 +213,7 @@ impl LinearMemory {
 // Not comparing based on memory content. That would be inefficient.
 impl PartialEq for LinearMemory {
     fn eq(&self, other: &LinearMemory) -> bool {
-        self.current == other.current && self.maximum == other.maximum
+        self.current == other.current && self.max == other.max
     }
 }
 
diff --git a/src/runtime/mod.rs b/src/runtime/mod.rs
index 4b47b0e4e..a43f01bf7 100644
--- a/src/runtime/mod.rs
+++ b/src/runtime/mod.rs
@@ -9,9 +9,9 @@ mod instance;
 mod table;
 mod sig_registry;
 
-pub use backend::Compiler;
-pub use instance::{Instance, Imports, Import};
-pub use module::{ModuleName, ItemName, Module};
+pub use self::backend::Compiler;
+pub use self::instance::{Instance, Imports, Import};
+pub use self::module::{ModuleName, ItemName, Module};
 
 /// Compile a webassembly module using the provided compiler and linked with the provided imports.
 pub fn compile(compiler: &dyn Compiler, wasm: &[u8], imports: &Imports) -> Result<Box<Instance>, String> {
diff --git a/src/runtime/module.rs b/src/runtime/module.rs
index 110a7e6ed..84828e6b6 100644
--- a/src/runtime/module.rs
+++ b/src/runtime/module.rs
@@ -1,12 +1,11 @@
 use crate::runtime::types::{
     Map,
-    FuncIndex, MemoryIndex, TableIndex, GlobalIndex,
-    Memory, Globals, GlobalDesc, FuncSig, Table,
+    FuncIndex, MemoryIndex, TableIndex, GlobalIndex, SigIndex,
+    Memory, Global, GlobalDesc, FuncSig, Table,
 };
 use crate::runtime::backend::FuncResolver;
 
 /// This is used to instantiate a new webassembly module.
-#[derive(Debug)]
 pub struct Module {
     pub functions: Box<dyn FuncResolver>,
     pub memories: Map<Memory, MemoryIndex>,
@@ -23,7 +22,8 @@ pub struct Module {
     pub data_initializers: Vec<DataInitializer>,
     pub start_func: FuncIndex,
 
-    pub signatures: Map<FuncSig, FuncIndex>,
+    pub signature_assoc: Map<SigIndex, FuncIndex>,
+    pub signatures: Map<FuncSig, SigIndex>,
 }
 
 pub type ModuleName = Vec<u8>;
diff --git a/src/runtime/sig_registry.rs b/src/runtime/sig_registry.rs
index cf9256ab1..949d2547e 100644
--- a/src/runtime/sig_registry.rs
+++ b/src/runtime/sig_registry.rs
@@ -1,5 +1,32 @@
 
+use hashbrown::HashMap;
+use crate::runtime::{
+    types::{Map, SigIndex, FuncSig},
+    vm,
+};
 
-pub struct SignatureRegistry {
-    
+pub struct SigRegistry {
+    sig_set: HashMap<FuncSig, vm::SigId>,
+    signatures: Map<vm::SigId, SigIndex>,
+}
+
+impl SigRegistry {
+    pub fn new() -> Self {
+        Self {
+            sig_set: HashMap::new(),
+            signatures: Map::new(),
+        }
+    }
+
+    pub fn into_vm_signatures(&self) -> *const vm::SigId {
+        self.signatures.as_ptr()
+    }
+
+    pub fn register(&mut self, signature: FuncSig, sig_index: SigIndex) {
+        let index = self.sig_set.len();
+        let vm_sig_id = *self.sig_set.entry(signature).or_insert_with(|| {
+            vm::SigId(index as u32)
+        });
+        self.signatures.push(vm_sig_id);
+    }
 }
\ No newline at end of file
diff --git a/src/runtime/table.rs b/src/runtime/table.rs
index 3c72290ab..10c237a6b 100644
--- a/src/runtime/table.rs
+++ b/src/runtime/table.rs
@@ -1,7 +1,7 @@
 use super::vm;
 use crate::runtime::types::{ElementType, Table};
 
-#[derive(Debug, Copy, Clone, PartialEq, Eq)]
+#[derive(Debug, Clone)]
 enum TableElements {
     /// This is intended to be a caller-checked Anyfunc.
     Anyfunc(Box<[vm::Anyfunc]>),
@@ -18,7 +18,7 @@ impl TableBacking {
         match table.ty {
             ElementType::Anyfunc => {
                 Self {
-                    elements: TableElements::Anyfunc(vec![vm::Anyfunc::null(); table.min].into_boxed_slice()),
+                    elements: TableElements::Anyfunc(vec![vm::Anyfunc::null(); table.min as usize].into_boxed_slice()),
                     max: table.max,
                 }
             }
diff --git a/src/runtime/types.rs b/src/runtime/types.rs
index 9fe58bd2a..0c31485ae 100644
--- a/src/runtime/types.rs
+++ b/src/runtime/types.rs
@@ -1,7 +1,10 @@
 use std::marker::PhantomData;
-use std::{slice, iter};
+use std::{
+    slice, iter,
+    ops::{Index, IndexMut},
+};
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub enum Type {
     /// The `i32` type.
     I32,
@@ -38,25 +41,25 @@ impl Val {
 
 impl From<i32> for Val {
     fn from(n: i32) -> Self {
-        Self::I32(n)
+        Val::I32(n)
     }
 }
 
 impl From<i64> for Val {
     fn from(n: i64) -> Self {
-        Self::I64(n)
+        Val::I64(n)
     }
 }
 
 impl From<f32> for Val {
     fn from(n: f32) -> Self {
-        Self::F32(n.to_bits())
+        Val::F32(n.to_bits())
     }
 }
 
 impl From<f64> for Val {
     fn from(n: f64) -> Self {
-        Self::I64(n.to_bits())
+        Val::F64(n.to_bits())
     }
 }
 
@@ -116,7 +119,7 @@ impl Memory {
 }
 
 /// A wasm func.
-#[derive(Debug, PartialEq, Eq)]
+#[derive(Debug, PartialEq, Eq, Hash)]
 pub struct FuncSig {
     pub params: Vec<Type>,
     pub returns: Vec<Type>,
@@ -137,7 +140,10 @@ where
     _marker: PhantomData<I>,
 }
 
-impl Map {
+impl<T, I> Map<T, I>
+where
+    I: MapIndex,
+{
     pub fn new() -> Self {
         Self {
             elems: Vec::new(),
@@ -165,6 +171,10 @@ impl Map {
         self.elems.push(value);
         I::new(len)
     }
+
+    pub fn as_ptr(&self) -> *const T {
+        self.elems.as_ptr()
+    }
 }
 
 impl<T, I> Index<I> for Map<T, I>
@@ -206,13 +216,13 @@ where
     type IntoIter = IterMut<'a, T, I>;
 
     fn into_iter(self) -> Self::IntoIter {
-        Iter::new(self.elems.iter_mut())
+        IterMut::new(self.elems.iter_mut())
     }
 }
 
 pub struct Iter<'a, T: 'a, I: MapIndex> {
-    enumerated: iter::Enumerate<slice::Iter<'A, T>>,
-    _marker: PhantomData,
+    enumerated: iter::Enumerate<slice::Iter<'a, T>>,
+    _marker: PhantomData<I>,
 }
 
 impl<'a, T: 'a, I: MapIndex> Iter<'a, T, I> {
@@ -227,18 +237,18 @@ impl<'a, T: 'a, I: MapIndex> Iter<'a, T, I> {
 impl<'a, T: 'a, I: MapIndex> Iterator for Iter<'a, T, I> {
     type Item = (I, &'a T);
 
-    fn next(&mut self) -> Self::Item {
-        self.enumerated.next().map(|i, v| (I::new(i), v))
+    fn next(&mut self) -> Option<Self::Item> {
+        self.enumerated.next().map(|(i, v)| (I::new(i), v))
     }
 }
 
 pub struct IterMut<'a, T: 'a, I: MapIndex> {
-    enumerated: iter::Enumerate<slice::Iter<'A, T>>,
-    _marker: PhantomData,
+    enumerated: iter::Enumerate<slice::IterMut<'a, T>>,
+    _marker: PhantomData<I>,
 }
 
 impl<'a, T: 'a, I: MapIndex> IterMut<'a, T, I> {
-    fn new(iter: slice::Iter<'a, T>) -> Self {
+    fn new(iter: slice::IterMut<'a, T>) -> Self {
         Self {
             enumerated: iter.enumerate(),
             _marker: PhantomData,
@@ -249,8 +259,8 @@ impl<'a, T: 'a, I: MapIndex> IterMut<'a, T, I> {
 impl<'a, T: 'a, I: MapIndex> Iterator for IterMut<'a, T, I> {
     type Item = (I, &'a mut T);
 
-    fn next(&mut self) -> Self::Item {
-        self.enumerated.next().map(|i, v| (I::new(i), v))
+    fn next(&mut self) -> Option<Self::Item> {
+        self.enumerated.next().map(|(i, v)| (I::new(i), v))
     }
 }
 
@@ -268,7 +278,7 @@ macro_rules! define_map_index {
             }
         }
     };
-    ($($ty:ident),*) => {
+    ($($ty:ident,)*) => {
         $(
             define_map_index!($ty);
         )*
@@ -277,5 +287,5 @@ macro_rules! define_map_index {
 
 define_map_index![
     FuncIndex, MemoryIndex, GlobalIndex, TableIndex,
-    SignatureIndex,
+    SigIndex,
 ];
\ No newline at end of file
diff --git a/src/runtime/vm.rs b/src/runtime/vm.rs
index 56100e183..b622768c2 100644
--- a/src/runtime/vm.rs
+++ b/src/runtime/vm.rs
@@ -1,15 +1,16 @@
 use std::{ptr, mem};
 use crate::runtime::{
-    types::{
-        MemoryIndex, TableIndex, GlobalIndex, FuncIndex,
-        SignatureIndex,
-    },
+    // types::{
+    //     MemoryIndex, TableIndex, GlobalIndex, FuncIndex,
+    //     SigIndex,
+    // },
     backing::{LocalBacking, ImportBacking},
+    sig_registry::SigRegistry,
 };
 
 #[derive(Debug)]
 #[repr(C)]
-pub struct Ctx<'a> {
+pub struct Ctx {
     /// A pointer to an array of locally-defined memories, indexed by `MemoryIndex`.
     pub memories: *mut LocalMemory,
 
@@ -32,14 +33,14 @@ pub struct Ctx<'a> {
     pub imported_funcs: *mut ImportedFunc,
 
     /// Signature identifiers for signature-checked indirect calls.
-    pub sig_ids: *mut SigId,
+    pub signatures: *const SigId,
 }
 
 impl Ctx {
     pub fn new(
         local_backing: &mut LocalBacking,
         import_backing: &mut ImportBacking,
-        sig_ids: *mut SigId,
+        sig_registry: &SigRegistry,
     ) -> Self {
         Self {
             memories: local_backing.vm_memories.as_mut_ptr(),
@@ -48,9 +49,10 @@ impl Ctx {
 
             imported_memories: import_backing.memories.as_mut_ptr(),
             imported_tables: import_backing.tables.as_mut_ptr(),
+            imported_globals: import_backing.globals.as_mut_ptr(),
             imported_funcs: import_backing.functions.as_mut_ptr(),
-            
-            sig_ids,
+
+            signatures: sig_registry.into_vm_signatures(),
         }
     }
 
@@ -82,7 +84,7 @@ impl Ctx {
         6 * (mem::size_of::<usize>() as u8)
     }
 
-    pub fn offset_sig_ids() -> u8 {
+    pub fn offset_signatures() -> u8 {
         7 * (mem::size_of::<usize>() as u8)
     }
 }
@@ -210,7 +212,7 @@ impl ImportedGlobal {
 
 #[derive(Debug, Clone)]
 #[repr(transparent)]
-pub struct SigId(u32);
+pub struct SigId(pub u32);
 
 /// Caller-checked anyfunc
 #[derive(Debug, Clone)]
@@ -225,7 +227,6 @@ impl Anyfunc {
         Self {
             func_data: ImportedFunc {
                 func: ptr::null(),
-                vmctx: ptr::null_mut(),
             },
             sig_id: SigId(u32::max_value()),
         }
@@ -235,9 +236,9 @@ impl Anyfunc {
         0 * (mem::size_of::<usize>() as u8)
     }
 
-    pub fn offset_vmctx() -> u8 {
-        1 * (mem::size_of::<usize>() as u8)
-    }
+    // pub fn offset_vmctx() -> u8 {
+    //     1 * (mem::size_of::<usize>() as u8)
+    // }
 
     pub fn offset_sig_id() -> u8 {
         2 * (mem::size_of::<usize>() as u8)
@@ -296,8 +297,8 @@ mod vm_offset_tests {
         );
 
         assert_eq!(
-            Ctx::offset_sig_ids() as usize,
-            offset_of!(Ctx => sig_ids).get_byte_offset(),
+            Ctx::offset_signatures() as usize,
+            offset_of!(Ctx => signatures).get_byte_offset(),
         );
     }
 
@@ -384,10 +385,10 @@ mod vm_offset_tests {
             offset_of!(Anyfunc => func_data: ImportedFunc => func).get_byte_offset(),
         );
 
-        assert_eq!(
-            Anyfunc::offset_vmctx() as usize,
-            offset_of!(Anyfunc => func_data: ImportedFunc => vmctx).get_byte_offset(),
-        );
+        // assert_eq!(
+        //     Anyfunc::offset_vmctx() as usize,
+        //     offset_of!(Anyfunc => func_data: ImportedFunc => vmctx).get_byte_offset(),
+        // );
 
         assert_eq!(
             Anyfunc::offset_sig_id() as usize,