Merge #383

383: Hook up wasi exit code to wasmer cli r=lachlansneff a=lachlansneff

Test by running:

```
> target/release/wasmer run examples/exit.wat
> echo $?
```

should echo "7".

Fixes (at least the exit code part) of #361.

Co-authored-by: Lachlan Sneff <lachlan.sneff@gmail.com>

CHANGELOG.md

@@ -5,6 +5,7 @@ All PRs to the Wasmer repository must add to this file.
 Blocks of changes will separated by version increments.
 
 ## **[Unreleased]**
+- [#383](https://github.com/wasmerio/wasmer/pull/383) Hook up wasi exit code to wasmer cli.
 - [#382](https://github.com/wasmerio/wasmer/pull/382) Improve error message on `--backend` flag to only suggest currently enabled backends
 - [#381](https://github.com/wasmerio/wasmer/pull/381) Allow retrieving propagated user errors.
 - [#379](https://github.com/wasmerio/wasmer/pull/379) Fix small return types from imported functions.

examples/exit.wat

@@ -0,0 +1,11 @@
+(module
+  (import "wasi_unstable" "proc_exit"      (func $proc_exit (param i32)))
+  (export "_start" (func $_start))
+
+  (memory 10)
+  (export "memory" (memory 0))
+
+  (func $_start
+    (call $proc_exit (i32.const 7))
+  )
+)

src/bin/wasmer.rs

@@ -11,12 +11,15 @@ use std::str::FromStr;
 use hashbrown::HashMap;
 use structopt::StructOpt;
 
-use wasmer::webassembly::InstanceABI;
 use wasmer::*;
 use wasmer_clif_backend::CraneliftCompiler;
 #[cfg(feature = "backend:llvm")]
 use wasmer_llvm_backend::LLVMCompiler;
-use wasmer_runtime::cache::{Cache as BaseCache, FileSystemCache, WasmHash, WASMER_VERSION_HASH};
+use wasmer_runtime::{
+    cache::{Cache as BaseCache, FileSystemCache, WasmHash, WASMER_VERSION_HASH},
+    error::RuntimeError,
+    Func, Value,
+};
 use wasmer_runtime_core::{
     self,
     backend::{Compiler, CompilerConfig},
@@ -301,18 +304,27 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
     };
 
     // TODO: refactor this
-    let (abi, import_object, _em_globals) = if wasmer_emscripten::is_emscripten_module(&module) {
+    if wasmer_emscripten::is_emscripten_module(&module) {
         let mut emscripten_globals = wasmer_emscripten::EmscriptenGlobals::new(&module);
-        (
-            InstanceABI::Emscripten,
-            wasmer_emscripten::generate_emscripten_env(&mut emscripten_globals),
-            Some(emscripten_globals), // TODO Em Globals is here to extend, lifetime, find better solution
+        let import_object = wasmer_emscripten::generate_emscripten_env(&mut emscripten_globals);
+        let mut instance = module
+            .instantiate(&import_object)
+            .map_err(|e| format!("Can't instantiate module: {:?}", e))?;
+
+        wasmer_emscripten::run_emscripten_instance(
+            &module,
+            &mut instance,
+            if let Some(cn) = &options.command_name {
+                cn
+            } else {
+                options.path.to_str().unwrap()
+            },
+            options.args.iter().map(|arg| arg.as_str()).collect(),
         )
+        .map_err(|e| format!("{:?}", e))?;
     } else {
         if cfg!(feature = "wasi") && wasmer_wasi::is_wasi_module(&module) {
-            (
-                InstanceABI::WASI,
-                wasmer_wasi::generate_import_object(
+            let import_object = wasmer_wasi::generate_import_object(
                 if let Some(cn) = &options.command_name {
                     [cn.clone()]
                 } else {
@@ -327,34 +339,46 @@ fn execute_wasm(options: &Run) -> Result<(), String> {
                     .map(|(k, v)| format!("{}={}", k, v).into_bytes())
                     .collect(),
                 options.pre_opened_directories.clone(),
-                ),
-                None,
-            )
-        } else {
-            (
-                InstanceABI::None,
-                wasmer_runtime_core::import::ImportObject::new(),
-                None,
-            )
-        }
-    };
+            );
 
-    let mut instance = module
+            let instance = module
                 .instantiate(&import_object)
                 .map_err(|e| format!("Can't instantiate module: {:?}", e))?;
 
-    webassembly::run_instance(
-        &module,
-        &mut instance,
-        abi,
-        if let Some(cn) = &options.command_name {
-            cn
+            let start: Func<(), ()> = instance.func("_start").map_err(|e| format!("{:?}", e))?;
+
+            let result = start.call();
+
+            if let Err(ref err) = result {
+                match err {
+                    RuntimeError::Trap { msg } => panic!("wasm trap occured: {}", msg),
+                    RuntimeError::Error { data } => {
+                        if let Some(error_code) = data.downcast_ref::<wasmer_wasi::ExitCode>() {
+                            std::process::exit(error_code.code as i32)
+                        }
+                    }
+                }
+                panic!("error: {:?}", err)
+            }
         } else {
-            options.path.to_str().unwrap()
-        },
-        options.args.iter().map(|arg| arg.as_str()).collect(),
-    )
+            let import_object = wasmer_runtime_core::import::ImportObject::new();
+            let instance = module
+                .instantiate(&import_object)
+                .map_err(|e| format!("Can't instantiate module: {:?}", e))?;
+
+            let args: Vec<Value> = options
+                .args
+                .iter()
+                .map(|arg| arg.as_str())
+                .map(|x| Value::I32(x.parse().unwrap()))
+                .collect();
+            instance
+                .dyn_func("main")
+                .map_err(|e| format!("{:?}", e))?
+                .call(&args)
                 .map_err(|e| format!("{:?}", e))?;
+        }
+    }
 
     Ok(())
 }

src/webassembly.rs

@@ -77,40 +77,3 @@ pub fn compile(buffer_source: &[u8]) -> Result<Module> {
     let module = runtime::compile(buffer_source)?;
     Ok(module)
 }
-
-// /// The same as `compile` but takes a `CompilerConfig` for the purpose of
-// /// changing the compiler's behavior
-// pub fn compile_with_config_with(
-//     buffer_source: &[u8],
-//     compiler_config: CompilerConfig,
-// ) -> Result<Module> {
-//     let module = runtime::compile_with_config(buffer_source, compiler_config)?;
-//     Ok(module)
-// }
-
-/// Performs common instance operations needed when an instance is first run
-/// including data setup, handling arguments and calling a main function
-pub fn run_instance(
-    module: &Module,
-    instance: &mut Instance,
-    abi: InstanceABI,
-    path: &str,
-    args: Vec<&str>,
-) -> CallResult<()> {
-    match abi {
-        InstanceABI::Emscripten => {
-            run_emscripten_instance(module, instance, path, args)?;
-        }
-        InstanceABI::WASI => {
-            instance.call("_start", &[])?;
-        }
-        InstanceABI::None => {
-            let args: Vec<Value> = args
-                .into_iter()
-                .map(|x| Value::I32(x.parse().unwrap()))
-                .collect();
-            instance.call("main", &args)?;
-        }
-    }
-    Ok(())
-}