kwasm imports

lib/kwasm-loader/src/lib.rs

@@ -34,12 +34,18 @@ impl Loader for KernelLoader {
             let globals: &[*mut LocalGlobal] = ::std::slice::from_raw_parts(ctx.globals, module.globals.len());
             globals.iter().map(|x| (**x).data).collect()
         };
+        let mut import_names: Vec<String> = vec![];
+        for (_, import) in &module.imported_functions {
+            let name = format!("{}##{}", module.namespace_table.get(import.namespace_index), module.name_table.get(import.name_index));
+            import_names.push(name);
+        }
         Ok(KernelInstance {
             context: ServiceContext::connect().map_err(|x| format!("{:?}", x))?,
             code: code.to_vec(),
             memory: memory,
             globals: globals,
             offsets: rm.get_offsets().unwrap(),
+            import_names: import_names,
         })
     }
 }
@@ -50,6 +56,7 @@ pub struct KernelInstance {
     memory: Option<Vec<u8>>,
     globals: Vec<u64>,
     offsets: Vec<usize>,
+    import_names: Vec<String>,
 }
 
 impl Instance for KernelInstance {
@@ -64,6 +71,7 @@ impl Instance for KernelInstance {
             globals: &self.globals,
             params: &args,
             entry_offset: self.offsets[id] as u32,
+            imports: &self.import_names,
         }).map_err(|x| format!("{:?}", x))?;
         Ok(ret as u64)
     }

lib/kwasm-loader/src/service.rs

@@ -53,11 +53,19 @@ struct RunCodeRequest {
     globals: *const u64,
     global_count: u32,
 
+    imported_funcs: *const ImportRequest,
+    imported_func_count: u32,
+
     entry_offset: u32,
     params: *const u64,
     param_count: u32,
 }
 
+#[repr(C)]
+struct ImportRequest {
+    name: [u8; 64],
+}
+
 pub struct RunProfile<'a> {
     pub code: &'a [u8],
     pub memory: Option<&'a [u8]>,
@@ -65,6 +73,7 @@ pub struct RunProfile<'a> {
     pub globals: &'a [u64],
     pub params: &'a [u64],
     pub entry_offset: u32,
+    pub imports: &'a [String]
 }
 
 pub struct ServiceContext {
@@ -79,6 +88,16 @@ impl ServiceContext {
     }
 
     pub fn run_code(&mut self, run: RunProfile) -> ServiceResult<i32> {
+        let imports: Vec<ImportRequest> = run.imports.iter().map(|x| {
+            let mut req: ImportRequest = unsafe { ::std::mem::zeroed() };
+            let x = x.as_bytes();
+            let mut count = req.name.len() - 1;
+            if x.len() < count {
+                count = x.len();
+            }
+            req.name[..count].copy_from_slice(&x[..count]);
+            req
+        }).collect();
         let req = RunCodeRequest {
             code: run.code.as_ptr(),
             code_len: run.code.len() as u32,
@@ -89,6 +108,8 @@ impl ServiceContext {
             table_count: 0,
             globals: run.globals.as_ptr(),
             global_count: run.globals.len() as u32,
+            imported_funcs: imports.as_ptr(),
+            imported_func_count: imports.len() as u32,
             params: run.params.as_ptr(),
             param_count: run.params.len() as u32,
             entry_offset: run.entry_offset,

lib/runtime-core/src/backing.rs

@@ -449,10 +449,17 @@ fn import_functions(
                 });
             }
             None => {
-                link_errors.push(LinkError::ImportNotFound {
-                    namespace: namespace.to_string(),
-                    name: name.to_string(),
-                });
+                if imports.allow_missing_functions {
+                    functions.push(vm::ImportedFunc {
+                        func: ::std::ptr::null(),
+                        vmctx: ::std::ptr::null_mut(),
+                    });
+                } else {
+                    link_errors.push(LinkError::ImportNotFound {
+                        namespace: namespace.to_string(),
+                        name: name.to_string(),
+                    });
+                }
             }
         }
     }

lib/runtime-core/src/import.rs

@@ -47,6 +47,7 @@ impl IsExport for Export {
 pub struct ImportObject {
     map: Rc<RefCell<HashMap<String, Box<dyn LikeNamespace>>>>,
     state_creator: Option<Rc<Fn() -> (*mut c_void, fn(*mut c_void))>>,
+    pub allow_missing_functions: bool,
 }
 
 impl ImportObject {
@@ -55,6 +56,7 @@ impl ImportObject {
         Self {
             map: Rc::new(RefCell::new(HashMap::new())),
             state_creator: None,
+            allow_missing_functions: false,
         }
     }
 
@@ -65,6 +67,7 @@ impl ImportObject {
         Self {
             map: Rc::new(RefCell::new(HashMap::new())),
             state_creator: Some(Rc::new(state_creator)),
+            allow_missing_functions: false,
         }
     }
 
@@ -116,6 +119,7 @@ impl ImportObject {
         Self {
             map: Rc::clone(&self.map),
             state_creator: self.state_creator.clone(),
+            allow_missing_functions: false,
         }
     }
 

src/bin/wasmer.rs

@@ -339,7 +339,8 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
     };
 
     if let Some(loader) = options.loader {
-        let import_object = wasmer_runtime_core::import::ImportObject::new();
+        let mut import_object = wasmer_runtime_core::import::ImportObject::new();
+        import_object.allow_missing_functions = true; // Import initialization might be left to the loader.
         let instance = module
             .instantiate(&import_object)
             .map_err(|e| format!("Can't instantiate module: {:?}", e))?;