adds new WasmImportLinkAttribute for C# and initial support for mono runtime.

Author: Timmy Silesmo

Cargo.lock

@@ -11,9 +11,7 @@ CLI tool to generate bindings for WIT documents and the component model.
 """
 
 [workspace]
-members = [
-  "crates/test-rust-wasm",
-]
+members = ["crates/test-rust-wasm"]
 resolver = "2"
 
 [workspace.package]
@@ -22,7 +20,7 @@ edition = "2021"
 [workspace.dependencies]
 anyhow = "1.0.72"
 bitflags = "2.3.3"
-heck =  { version = "0.4", features = ["unicode"] }
+heck = { version = "0.4", features = ["unicode"] }
 pulldown-cmark = { version = "0.9", default-features = false }
 clap = { version = "4.3.19", features = ["derive"] }
 env_logger = "0.10.0"
@@ -52,22 +50,19 @@ clap = { workspace = true }
 wit-bindgen-core = { workspace = true }
 wit-bindgen-rust = { workspace = true, features = ['clap'], optional = true }
 wit-bindgen-c = { workspace = true, features = ['clap'], optional = true }
-wit-bindgen-markdown = { workspace = true, features = ['clap'], optional = true }
-wit-bindgen-teavm-java = { workspace = true, features = ['clap'], optional = true }
+wit-bindgen-markdown = { workspace = true, features = [
+  'clap',
+], optional = true }
+wit-bindgen-teavm-java = { workspace = true, features = [
+  'clap',
+], optional = true }
 wit-bindgen-go = { workspace = true, features = ['clap'], optional = true }
 wit-bindgen-csharp = { workspace = true, features = ['clap'], optional = true }
 wit-component = { workspace = true }
 wasm-encoder = { workspace = true }
 
 [features]
-default = [
-  'c',
-  'rust',
-  'markdown',
-  'teavm-java',
-  'go',
-  'csharp-naot',
-]
+default = ['c', 'rust', 'markdown', 'teavm-java', 'go', 'csharp-naot']
 c = ['dep:wit-bindgen-c']
 rust = ['dep:wit-bindgen-rust']
 markdown = ['dep:wit-bindgen-markdown']
@@ -83,3 +78,5 @@ wasmtime = { version = "15", features = ['component-model'] }
 wasmtime-wasi = { workspace = true }
 test-artifacts = { path = 'crates/test-rust-wasm/artifacts' }
 wit-parser = { workspace = true }
+wasmparser = "0.118.0"
+wasm-encoder = { workspace = true }

Cargo.toml

@@ -3,7 +3,9 @@ use std::{fs, path::PathBuf};
 
 use heck::ToUpperCamelCase;
 
-pub struct CSProject {
+pub struct CSProject;
+
+pub struct CSProjectLLVMBuilder {
     name: String,
     dir: PathBuf,
     aot: bool,
@@ -12,9 +14,17 @@ pub struct CSProject {
     wasm_imports: Vec<(String, String)>,
 }
 
+pub struct CSProjectMonoBuilder {
+    name: String,
+    dir: PathBuf,
+    aot: bool,
+    clean_targets: bool,
+    world_name: String,
+}
+
 impl CSProject {
-    pub fn new(dir: PathBuf, name: &str, world_name: &str) -> CSProject {
-        CSProject {
+    pub fn new(dir: PathBuf, name: &str, world_name: &str) -> CSProjectLLVMBuilder {
+        CSProjectLLVMBuilder {
             name: name.to_string(),
             dir,
             aot: false,
@@ -24,6 +34,18 @@ impl CSProject {
         }
     }
 
+    pub fn new_mono(dir: PathBuf, name: &str, world_name: &str) -> CSProjectMonoBuilder {
+        CSProjectMonoBuilder {
+            name: name.to_string(),
+            dir,
+            aot: false,
+            clean_targets: false,
+            world_name: world_name.to_string(),
+        }
+    }
+}
+
+impl CSProjectLLVMBuilder {
     pub fn generate(&self) -> Result<()> {
         let name = &self.name;
         let world = &self.world_name.replace("-", "_");
@@ -148,12 +170,125 @@ impl CSProject {
         self.aot = true;
     }
 
-    pub fn clean(&mut self) {
+    pub fn clean(&mut self) -> &mut Self {
         self.clean_targets = true;
+
+        self
     }
 
     pub fn add_import(&mut self, module_name: &str, func_name: &str) {
         self.wasm_imports
             .push((module_name.to_string(), func_name.to_string()));
     }
 }
+
+impl CSProjectMonoBuilder {
+    pub fn generate(&self) -> Result<()> {
+        let name = &self.name;
+        let world = &self.world_name.replace("-", "_");
+        let snake_world = world.to_upper_camel_case();
+
+        let aot = self.aot;
+
+        fs::write(
+            self.dir.join("rd.xml"),
+            format!(
+                r#"<Directives xmlns="http://schemas.microsoft.com/netfx/2013/01/metadata">
+            <Application>
+                <Assembly Name="{name}">
+                </Assembly>
+            </Application>
+        </Directives>"#
+            ),
+        )?;
+
+        let mut csproj = format!(
+            "<Project Sdk=\"Microsoft.NET.Sdk\">
+    
+        <PropertyGroup>
+            <TargetFramework>net9.0</TargetFramework>
+            <RuntimeIdentifier>wasi-wasm</RuntimeIdentifier>
+
+            <TargetOs>wasi</TargetOs>
+            <WasmBuildNative>{aot}</WasmBuildNative>
+            <WasmNativeStrip>false</WasmNativeStrip>
+            <IsBrowserWasmProject>false</IsBrowserWasmProject>
+            <WasmSingleFileBundle>true</WasmSingleFileBundle>
+
+            <RootNamespace>{name}</RootNamespace>
+            <ImplicitUsings>enable</ImplicitUsings>
+            <Nullable>enable</Nullable>
+            <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+        </PropertyGroup>
+        
+        <PropertyGroup>
+            <PublishTrimmed>true</PublishTrimmed>
+            <AssemblyName>{name}</AssemblyName>
+        </PropertyGroup>
+
+        <ItemGroup>
+          <NativeLibrary Include=\"{world}_component_type.o\" />
+        </ItemGroup>
+
+        <ItemGroup>
+            <RdXmlFile Include=\"rd.xml\" />
+        </ItemGroup>
+        "
+        );
+
+        if self.aot {
+            fs::write(
+                self.dir.join("nuget.config"),
+                r#"<?xml version="1.0" encoding="utf-8"?>
+            <configuration>
+                <config>
+                    <add key="globalPackagesFolder" value=".packages" />
+                </config>
+                <packageSources>
+                    <!--To inherit the global NuGet package sources remove the <clear/> line below -->
+                    <clear />
+                    <add key="nuget" value="https://api.nuget.org/v3/index.json" />
+                    <add key="dotnet9" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet9/nuget/v3/index.json" />
+                </packageSources>
+            </configuration>"#,
+            )?;
+        }
+
+        if self.clean_targets {
+            let mut wasm_filename = self.dir.join(name);
+            wasm_filename.set_extension("wasm");
+            // In CI we run out of disk space if we don't clean up the files, we don't need to keep any of it around.
+            csproj.push_str(&format!(
+                "<Target Name=\"CleanAndDelete\"  AfterTargets=\"Clean\">
+                <!-- Remove obj folder -->
+                <RemoveDir Directories=\"$(BaseIntermediateOutputPath)\" />
+                <!-- Remove bin folder -->
+                <RemoveDir Directories=\"$(BaseOutputPath)\" />
+                <RemoveDir Directories=\"{}\" />
+                <RemoveDir Directories=\".packages\" />
+            </Target>",
+                wasm_filename.display()
+            ));
+        }
+
+        csproj.push_str(
+            r#"</Project>
+            "#,
+        );
+
+        let camel = snake_world.to_upper_camel_case();
+        fs::write(self.dir.join(format!("{camel}.csproj")), csproj)?;
+
+        Ok(())
+    }
+
+    pub fn aot(&mut self) {
+        self.aot = true;
+    }
+
+    pub fn clean(&mut self) -> &mut Self {
+        self.clean_targets = true;
+
+        self
+    }
+}

crates/csharp/src/csproj.rs

@@ -45,6 +45,10 @@ pub struct Opts {
     pub string_encoding: StringEncoding,
     #[cfg_attr(feature = "clap", arg(long))]
     pub generate_stub: bool,
+
+    // TODO: This should only temporarily needed until mono and native aot aligns.
+    #[cfg_attr(feature = "clap", arg(short, long, value_enum))]
+    pub runtime: CSharpRuntime,
 }
 
 impl Opts {
@@ -56,6 +60,14 @@ impl Opts {
     }
 }
 
+#[derive(Default, Debug, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "clap", derive(clap::ValueEnum))]
+pub enum CSharpRuntime {
+    #[default]
+    NativeAOT,
+    Mono,
+}
+
 struct InterfaceFragment {
     csharp_src: String,
     csharp_interop_src: String,
@@ -487,6 +499,22 @@ impl WorldGenerator for CSharp {
             );
         }
 
+        //TODO: This is currently neede for mono even if it's built as a library.
+        if self.opts.runtime == CSharpRuntime::Mono {
+            files.push(
+                &format!("MonoEntrypoint.cs",),
+                indent(
+                    r#"
+                public class MonoEntrypoint() {
+                    public static void Main() {
+                    }
+                }
+                "#,
+                )
+                .as_bytes(),
+            );
+        }
+
         files.push(
             &format!("{snake}_component_type.o",),
             component_type_object::object(resolve, id, self.opts.string_encoding)
@@ -599,7 +627,7 @@ impl InterfaceGenerator<'_> {
         });
     }
 
-    fn import(&mut self, _module: &String, func: &Function) {
+    fn import(&mut self, module: &String, func: &Function) {
         if func.kind != FunctionKind::Freestanding {
             todo!("resources");
         }
@@ -666,12 +694,14 @@ impl InterfaceGenerator<'_> {
             .join(", ");
 
         let import_name = &func.name;
+
         uwrite!(
             self.csharp_interop_src,
             r#"
             internal static class {camel_name}Interop
             {{
-                [DllImport("*", EntryPoint = "{import_name}")]
+                [WasmImportLinkage]
+                [DllImport("{module}", EntryPoint = "{import_name}")]
                 internal static extern {wasm_result_type} wasmImport{camel_name}({wasm_params});
             }}
             "#

crates/csharp/src/lib.rs

@@ -71,6 +71,7 @@ macro_rules! codegen_test {
                     wit_bindgen_csharp::Opts {
                         generate_stub: true,
                         string_encoding: StringEncoding::UTF8,
+                        runtime: Default::default(),
                     }
                     .build()
                     .generate(resolve, world, files)