Make module info store FuncSig, not Arc<FuncSig>

lib/runtime-core/src/backend.rs

@@ -23,6 +23,7 @@ pub use crate::sig_registry::SigRegistry;
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 pub enum Backend {
     Cranelift,
+    LLVM,
 }
 
 /// This type cannot be constructed from

lib/runtime-core/src/backing.rs

@@ -14,7 +14,7 @@ use crate::{
     },
     vm,
 };
-use std::{slice, sync::Arc};
+use std::slice;
 
 #[derive(Debug)]
 pub struct LocalBacking {
@@ -172,10 +172,11 @@ impl LocalBacking {
                     table.anyfunc_direct_access_mut(|elements| {
                         for (i, &func_index) in init.elements.iter().enumerate() {
                             let sig_index = module.info.func_assoc[func_index];
-                            let signature = &module.info.signatures[sig_index];
-                            let sig_id = vm::SigId(
-                                SigRegistry.lookup_sig_index(Arc::clone(&signature)).index() as u32,
-                            );
+                            // let signature = &module.info.signatures[sig_index];
+                            let signature = SigRegistry
+                                .lookup_signature_ref(&module.info.signatures[sig_index]);
+                            let sig_id =
+                                vm::SigId(SigRegistry.lookup_sig_index(signature).index() as u32);
 
                             let (func, ctx) = match func_index.local_or_import(module) {
                                 LocalOrImport::Local(local_func_index) => (
@@ -210,10 +211,11 @@ impl LocalBacking {
                     table.anyfunc_direct_access_mut(|elements| {
                         for (i, &func_index) in init.elements.iter().enumerate() {
                             let sig_index = module.info.func_assoc[func_index];
-                            let signature = &module.info.signatures[sig_index];
-                            let sig_id = vm::SigId(
-                                SigRegistry.lookup_sig_index(Arc::clone(&signature)).index() as u32,
-                            );
+                            let signature = SigRegistry
+                                .lookup_signature_ref(&module.info.signatures[sig_index]);
+                            // let signature = &module.info.signatures[sig_index];
+                            let sig_id =
+                                vm::SigId(SigRegistry.lookup_sig_index(signature).index() as u32);
 
                             let (func, ctx) = match func_index.local_or_import(module) {
                                 LocalOrImport::Local(local_func_index) => (
@@ -379,7 +381,7 @@ fn import_functions(
                 ctx,
                 signature,
             }) => {
-                if *expected_sig == signature {
+                if *expected_sig == *signature {
                     functions.push(vm::ImportedFunc {
                         func: func.inner(),
                         vmctx: match ctx {
@@ -391,8 +393,8 @@ fn import_functions(
                     link_errors.push(LinkError::IncorrectImportSignature {
                         namespace: namespace.to_string(),
                         name: name.to_string(),
-                        expected: expected_sig.clone(),
-                        found: signature.clone(),
+                        expected: (*expected_sig).clone(),
+                        found: (*signature).clone(),
                     });
                 }
             }

lib/runtime-core/src/error.rs

@@ -1,7 +1,6 @@
 use crate::types::{
     FuncSig, GlobalDescriptor, MemoryDescriptor, MemoryIndex, TableDescriptor, TableIndex, Type,
 };
-use std::sync::Arc;
 
 pub type Result<T> = std::result::Result<T, Error>;
 pub type CompileResult<T> = std::result::Result<T, CompileError>;
@@ -42,8 +41,8 @@ pub enum LinkError {
     IncorrectImportSignature {
         namespace: String,
         name: String,
-        expected: Arc<FuncSig>,
-        found: Arc<FuncSig>,
+        expected: FuncSig,
+        found: FuncSig,
     },
     ImportNotFound {
         namespace: String,
@@ -117,16 +116,9 @@ impl PartialEq for RuntimeError {
 /// Comparing two `ResolveError`s always evaluates to false.
 #[derive(Debug, Clone)]
 pub enum ResolveError {
-    Signature {
-        expected: Arc<FuncSig>,
-        found: Vec<Type>,
-    },
-    ExportNotFound {
-        name: String,
-    },
-    ExportWrongType {
-        name: String,
-    },
+    Signature { expected: FuncSig, found: Vec<Type> },
+    ExportNotFound { name: String },
+    ExportWrongType { name: String },
 }
 
 impl PartialEq for ResolveError {

lib/runtime-core/src/instance.rs

@@ -7,6 +7,7 @@ use crate::{
     import::{ImportObject, LikeNamespace},
     memory::Memory,
     module::{ExportIndex, Module, ModuleInner},
+    sig_registry::SigRegistry,
     table::Table,
     typed_func::{Func, Safe, WasmTypeList},
     types::{FuncIndex, FuncSig, GlobalIndex, LocalOrImport, MemoryIndex, TableIndex, Value},
@@ -112,11 +113,12 @@ impl Instance {
                 .func_assoc
                 .get(*func_index)
                 .expect("broken invariant, incorrect func index");
-            let signature = &self.module.info.signatures[sig_index];
+            let signature =
+                SigRegistry.lookup_signature_ref(&self.module.info.signatures[sig_index]);
 
             if signature.params() != Args::types() || signature.returns() != Rets::types() {
                 Err(ResolveError::Signature {
-                    expected: Arc::clone(&signature),
+                    expected: (*signature).clone(),
                     found: Args::types().to_vec(),
                 })?;
             }
@@ -183,7 +185,8 @@ impl Instance {
                 .func_assoc
                 .get(*func_index)
                 .expect("broken invariant, incorrect func index");
-            let signature = Arc::clone(&self.module.info.signatures[sig_index]);
+            let signature =
+                SigRegistry.lookup_signature_ref(&self.module.info.signatures[sig_index]);
 
             Ok(DynFunc {
                 signature,
@@ -374,13 +377,10 @@ impl InstanceInner {
             }
         };
 
-        let signature = &module.info.signatures[sig_index];
+        let signature = SigRegistry.lookup_signature_ref(&module.info.signatures[sig_index]);
+        // let signature = &module.info.signatures[sig_index];
 
-        (
-            unsafe { FuncPointer::new(func_ptr) },
-            ctx,
-            Arc::clone(signature),
-        )
+        (unsafe { FuncPointer::new(func_ptr) }, ctx, signature)
     }
 
     fn get_memory_from_index(&self, module: &ModuleInner, mem_index: MemoryIndex) -> Memory {
@@ -457,7 +457,7 @@ impl<'a> DynFunc<'a> {
     pub fn call(&mut self, params: &[Value]) -> CallResult<Vec<Value>> {
         if !self.signature.check_param_value_types(params) {
             Err(ResolveError::Signature {
-                expected: self.signature.clone(),
+                expected: (*self.signature).clone(),
                 found: params.iter().map(|val| val.ty()).collect(),
             })?
         }

lib/runtime-core/src/module.rs

@@ -46,7 +46,7 @@ pub struct ModuleInfo {
     pub start_func: Option<FuncIndex>,
 
     pub func_assoc: Map<FuncIndex, SigIndex>,
-    pub signatures: Map<SigIndex, Arc<FuncSig>>,
+    pub signatures: Map<SigIndex, FuncSig>,
     pub backend: Backend,
 
     pub namespace_table: StringTable<NamespaceIndex>,

lib/runtime-core/src/sig_registry.rs

@@ -49,4 +49,20 @@ impl SigRegistry {
         let global = (*GLOBAL_SIG_REGISTRY).read();
         Arc::clone(&global.sig_assoc[sig_index])
     }
+
+    pub fn lookup_signature_ref(&self, func_sig: &FuncSig) -> Arc<FuncSig> {
+        let mut global = (*GLOBAL_SIG_REGISTRY).write();
+        let global = &mut *global;
+
+        let func_table = &mut global.func_table;
+        let sig_assoc = &mut global.sig_assoc;
+
+        if func_table.contains_key(func_sig) {
+            Arc::clone(&sig_assoc[func_table[func_sig]])
+        } else {
+            let arc = Arc::new(func_sig.clone());
+            func_table.insert(Arc::clone(&arc), sig_assoc.push(Arc::clone(&arc)));
+            arc
+        }
+    }
 }