[wasmtime-api] Multi value api support (#448)

wasmtime-api/examples/multi.rs

@@ -0,0 +1,89 @@
+//! Translation of multi example
+
+extern crate alloc;
+
+use alloc::rc::Rc;
+use core::cell::Ref;
+use failure::{bail, format_err, Error};
+use std::fs::read;
+use wasmtime_api::*;
+
+struct Callback;
+
+impl Callable for Callback {
+    fn call(&self, args: &[Val], results: &mut [Val]) -> Result<(), HostRef<Trap>> {
+        println!("Calling back...");
+        println!("> {} {}", args[0].i32(), args[1].i64());
+
+        results[0] = Val::I64(args[1].i64() + 1);
+        results[1] = Val::I32(args[0].i32() + 1);
+        Ok(())
+    }
+}
+
+fn main() -> Result<(), Error> {
+    // Initialize.
+    println!("Initializing...");
+    let engine = HostRef::new(Engine::new(Config::default()));
+    let store = HostRef::new(Store::new(engine));
+
+    // Load binary.
+    println!("Loading binary...");
+    let binary = read("examples/multi.wasm")?;
+
+    // Compile.
+    println!("Compiling module...");
+    let module = HostRef::new(
+        Module::new(store.clone(), &binary)
+            .map_err(|_| format_err!("> Error compiling module!"))?,
+    );
+
+    // Create external print functions.
+    println!("Creating callback...");
+    let callback_type = FuncType::new(
+        Box::new([ValType::I32, ValType::I64]),
+        Box::new([ValType::I64, ValType::I32]),
+    );
+    let callback_func = HostRef::new(Func::new(store.clone(), callback_type, Rc::new(Callback)));
+
+    // Instantiate.
+    println!("Instantiating module...");
+    let imports = vec![callback_func.into()];
+    let instance = HostRef::new(
+        Instance::new(store.clone(), module, imports.as_slice())
+            .map_err(|_| format_err!("> Error instantiating module!"))?,
+    );
+
+    // Extract export.
+    println!("Extracting export...");
+    let exports = Ref::map(instance.borrow(), |instance| instance.exports());
+    if exports.len() == 0 {
+        bail!("> Error accessing exports!");
+    }
+    let run_func = exports[0]
+        .func()
+        .ok_or_else(|| format_err!("> Error accessing exports!"))?;
+
+    // Call.
+    println!("Calling export...");
+    let args = vec![Val::I32(1), Val::I64(3)];
+    let results = run_func.borrow().call(&args);
+    if let Err(_) = results {
+        bail!("> Error calling function!");
+    }
+
+    let results = results.unwrap();
+    println!("Printing result...");
+    println!("> {} {}", results[0].i64(), results[1].i32());
+
+    debug_assert!(results[0].i64() == 4);
+    debug_assert!(results[1].i32() == 2);
+
+    // Shut down.
+    println!("Shutting down...");
+    drop(store);
+
+    // All done.
+    println!("Done.");
+    Ok(())
+}

wasmtime-api/examples/multi.wat

@@ -0,0 +1,7 @@
+(module
+  (func $f (import "" "f") (param i32 i64) (result i64 i32))
+
+  (func $g (export "g") (param i32 i64) (result i64 i32)
+    (call $f (local.get 0) (local.get 1))
+  )
+)

wasmtime-api/src/values.rs

@@ -60,6 +60,46 @@ impl Val {
     pub fn from_f64_bits(v: u64) -> Val {
         Val::F64(v)
     }
+
+    pub fn i32(&self) -> i32 {
+        if let Val::I32(i) = self {
+            *i
+        } else {
+            panic!("Invalid conversion of {:?} to i32.", self);
+        }
+    }
+
+    pub fn i64(&self) -> i64 {
+        if let Val::I64(i) = self {
+            *i
+        } else {
+            panic!("Invalid conversion of {:?} to i64.", self);
+        }
+    }
+
+    pub fn f32(&self) -> f32 {
+        RuntimeValue::F32(self.f32_bits()).unwrap_f32()
+    }
+
+    pub fn f64(&self) -> f64 {
+        RuntimeValue::F64(self.f64_bits()).unwrap_f64()
+    }
+
+    pub fn f32_bits(&self) -> u32 {
+        if let Val::F32(i) = self {
+            *i
+        } else {
+            panic!("Invalid conversion of {:?} to f32.", self);
+        }
+    }
+
+    pub fn f64_bits(&self) -> u64 {
+        if let Val::F64(i) = self {
+            *i
+        } else {
+            panic!("Invalid conversion of {:?} to f64.", self);
+        }
+    }
 }
 
 impl From<i32> for Val {
@@ -88,41 +128,25 @@ impl From<f64> for Val {
 
 impl Into<i32> for Val {
     fn into(self) -> i32 {
-        if let Val::I32(i) = self {
-            i
-        } else {
-            panic!("Invalid conversion of {:?} to i32.", self);
-        }
+        self.i32()
     }
 }
 
 impl Into<i64> for Val {
     fn into(self) -> i64 {
-        if let Val::I64(i) = self {
-            i
-        } else {
-            panic!("Invalid conversion of {:?} to i64.", self);
-        }
+        self.i64()
     }
 }
 
 impl Into<f32> for Val {
     fn into(self) -> f32 {
-        if let Val::F32(i) = self {
-            RuntimeValue::F32(i).unwrap_f32()
-        } else {
-            panic!("Invalid conversion of {:?} to f32.", self);
-        }
+        self.f32()
     }
 }
 
 impl Into<f64> for Val {
     fn into(self) -> f64 {
-        if let Val::F64(i) = self {
-            RuntimeValue::F64(i).unwrap_f64()
-        } else {
-            panic!("Invalid conversion of {:?} to f64.", self);
-        }
+        self.f64()
     }
 }
 

wasmtime-api/src/wasm.rs

@@ -1651,3 +1651,12 @@ pub unsafe extern "C" fn wasm_instance_set_host_info_with_finalizer(
     };
     (*instance).instance.anyref().set_host_info(info);
 }
+
+#[no_mangle]
+pub unsafe extern "C" fn wasm_valtype_vec_copy(
+    out: *mut wasm_valtype_vec_t,
+    src: *mut wasm_valtype_vec_t,
+) {
+    let slice = slice::from_raw_parts((*src).data, (*src).size);
+    (*out).set_from_slice(slice);
+}