Add first draft of wasmer create-exe

lib/cli/src/commands/create_exe.rs

@@ -0,0 +1,273 @@
+//! Create a standalone native executable for a given Wasm file.
+
+use crate::store::{CompilerOptions, EngineType};
+use anyhow::{Context, Result};
+use std::env;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::process::Command;
+use structopt::StructOpt;
+use wasmer::*;
+
+const WASMER_MAIN_C_SOURCE: &[u8] = include_bytes!("wasmer_create_exe_main.c");
+
+// TODO: to get this working locally I had to add wasmer_wasm.h and wasm.h to `.wasmer/include` manually.
+// this needs to be fixed before we can ship this.
+
+#[derive(Debug, StructOpt)]
+/// The options for the `wasmer create-exe` subcommand
+pub struct CreateExe {
+    /// Input file
+    #[structopt(name = "FILE", parse(from_os_str))]
+    path: PathBuf,
+
+    /// Output file
+    #[structopt(name = "OUTPUT PATH", short = "o", parse(from_os_str))]
+    output: PathBuf,
+
+    /// Compilation Target triple
+    #[structopt(long = "target")]
+    target_triple: Option<Triple>,
+
+    #[structopt(flatten)]
+    compiler: CompilerOptions,
+
+    #[structopt(short = "m", multiple = true)]
+    cpu_features: Vec<CpuFeature>,
+
+    /// Additional libraries to link against.
+    /// This is useful for fixing linker errors that may occur on some systems.
+    #[structopt(short = "l", multiple = true)]
+    libraries: Vec<String>,
+}
+
+impl CreateExe {
+    /// Runs logic for the `compile` subcommand
+    pub fn execute(&self) -> Result<()> {
+        let target = self
+            .target_triple
+            .as_ref()
+            .map(|target_triple| {
+                let mut features = self
+                    .cpu_features
+                    .clone()
+                    .into_iter()
+                    .fold(CpuFeature::set(), |a, b| a | b);
+                // Cranelift requires SSE2, so we have this "hack" for now to facilitate
+                // usage
+                features |= CpuFeature::SSE2;
+                Target::new(target_triple.clone(), features)
+            })
+            .unwrap_or_default();
+        let engine_type = EngineType::ObjectFile;
+        let (store, compiler_type) = self
+            .compiler
+            .get_store_for_target_and_engine(target.clone(), engine_type)?;
+
+        println!("Engine: {}", engine_type.to_string());
+        println!("Compiler: {}", compiler_type.to_string());
+        println!("Target: {}", target.triple());
+
+        let working_dir = tempfile::tempdir()?;
+        let starting_cd = env::current_dir()?;
+        let output_path = starting_cd.join(&self.output);
+        env::set_current_dir(&working_dir)?;
+
+        // TODO: encapsulate compile code
+
+        #[cfg(not(windows))]
+        let wasm_object_path = PathBuf::from("wasm.o");
+        #[cfg(windows)]
+        let wasm_object_path = PathBuf::from("wasm.obj");
+
+        let wasm_module_path = starting_cd.join(&self.path);
+
+        let header_file_path = Path::new("my_wasm.h");
+        let module =
+            Module::from_file(&store, &wasm_module_path).context("failed to compile Wasm")?;
+        let _ = module.serialize_to_file(&wasm_object_path)?;
+
+        let artifact: &wasmer_engine_object_file::ObjectFileArtifact =
+            module.artifact().as_ref().downcast_ref().context(
+                "Engine type is ObjectFile but could not downcast artifact into ObjectFileArtifact",
+            )?;
+        let symbol_registry = artifact.symbol_registry();
+        let metadata_length = artifact.metadata_length();
+        let module_info = module.info();
+        let header_file_src = crate::c_gen::object_file_header::generate_header_file(
+            module_info,
+            symbol_registry,
+            metadata_length,
+        );
+
+        let header_path = header_file_path.clone();
+        // for C code
+        let mut header = std::fs::OpenOptions::new()
+            .create(true)
+            .truncate(true)
+            .write(true)
+            .open(&header_path)?;
+
+        use std::io::Write;
+        header.write(header_file_src.as_bytes())?;
+
+        // auto compilation
+        //
+
+        // write C src to disk
+        let c_src_path = Path::new("wasmer_main.c");
+        #[cfg(not(windows))]
+        let c_src_obj = PathBuf::from("wasmer_main.o");
+        #[cfg(windows)]
+        let c_src_obj = PathBuf::from("wasmer_main.obj");
+
+        {
+            let mut c_src_file = fs::OpenOptions::new()
+                .create_new(true)
+                .write(true)
+                .open(&c_src_path)
+                .context("Failed to open C source code file")?;
+            // TODO:
+            c_src_file.write_all(WASMER_MAIN_C_SOURCE)?;
+        }
+        run_c_compile(&c_src_path, &c_src_obj).context("Failed to compile C source code")?;
+        LinkCode {
+            object_paths: vec![c_src_obj, wasm_object_path],
+            output_path,
+            additional_libraries: self.libraries.clone(),
+            ..Default::default()
+        }
+        .run()
+        .context("Failed to link objects together")?;
+
+        eprintln!(
+            "✔ Native executable compiled successfully to `{}`.",
+            self.output.display(),
+        );
+
+        Ok(())
+    }
+}
+
+fn get_wasmer_include_directory() -> anyhow::Result<PathBuf> {
+    let mut path = PathBuf::from(env::var("WASMER_DIR")?);
+    path.push("include");
+    Ok(path)
+}
+
+fn get_libwasmer_path() -> anyhow::Result<PathBuf> {
+    let mut path = PathBuf::from(env::var("WASMER_DIR")?);
+    path.push("lib");
+
+    #[cfg(not(windows))]
+    path.push("libwasmer.a");
+    #[cfg(windows)]
+    path.push("libwasmer.lib");
+
+    Ok(path)
+}
+
+/// Compile the C code.
+fn run_c_compile(path_to_c_src: &Path, output_name: &Path) -> anyhow::Result<()> {
+    #[cfg(not(windows))]
+    let c_compiler = "cc";
+    #[cfg(windows)]
+    let c_compiler = "clang++";
+
+    let output = Command::new(c_compiler)
+        .arg("-O2")
+        .arg("-c")
+        .arg(path_to_c_src)
+        .arg("-I")
+        .arg(get_wasmer_include_directory()?)
+        .arg("-o")
+        .arg(output_name)
+        .output()?;
+
+    if !output.status.success() {
+        bail!(
+            "C code compile failed with: stdout: {}\n\nstderr: {}",
+            std::str::from_utf8(&output.stdout)
+                .expect("stdout is not utf8! need to handle arbitrary bytes"),
+            std::str::from_utf8(&output.stderr)
+                .expect("stderr is not utf8! need to handle arbitrary bytes")
+        );
+    }
+    Ok(())
+}
+
+/// Data used to run a linking command for generated artifacts.
+#[derive(Debug)]
+struct LinkCode {
+    /// Path to the linker used to run the linking command.
+    linker_path: PathBuf,
+    /// String used as an optimization flag.
+    optimization_flag: String,
+    /// Paths of objects to link.
+    object_paths: Vec<PathBuf>,
+    /// Additional libraries to link against.
+    additional_libraries: Vec<String>,
+    /// Path to the output target.
+    output_path: PathBuf,
+    /// Path to the static libwasmer library.
+    libwasmer_path: PathBuf,
+}
+
+impl Default for LinkCode {
+    fn default() -> Self {
+        #[cfg(not(windows))]
+        let linker = "cc";
+        #[cfg(windows)]
+        let linker = "clang";
+        Self {
+            linker_path: PathBuf::from(linker),
+            optimization_flag: String::from("-O2"),
+            object_paths: vec![],
+            additional_libraries: vec![],
+            output_path: PathBuf::from("a.out"),
+            libwasmer_path: get_libwasmer_path().unwrap(),
+        }
+    }
+}
+
+impl LinkCode {
+    // TODO: `wasmer create-exe` needs a command line flag for extra libraries to link aganist
+    // or perhaps we just want to add a flag for passing things to the linker
+    fn run(&self) -> anyhow::Result<()> {
+        let mut command = Command::new(&self.linker_path);
+        let command = command
+            .arg(&self.optimization_flag)
+            .args(
+                self.object_paths
+                    .iter()
+                    .map(|path| path.canonicalize().unwrap()),
+            )
+            .arg(
+                &self
+                    .libwasmer_path
+                    .canonicalize()
+                    .context("Failed to find libwasmer")?,
+            );
+        #[cfg(windows)]
+        let command = command.arg("-luserenv").arg("-lWs2_32").arg("-ladvapi32");
+        #[cfg(not(windows))]
+        let command = command.arg("-ldl").arg("-lm").arg("-pthread");
+        let link_aganist_extra_libs = self
+            .additional_libraries
+            .iter()
+            .map(|lib| format!("-l{}", lib));
+        let command = command.args(link_aganist_extra_libs);
+        let output = command.arg("-o").arg(&self.output_path).output()?;
+
+        if !output.status.success() {
+            bail!(
+                "linking failed with: stdout: {}\n\nstderr: {}",
+                std::str::from_utf8(&output.stdout)
+                    .expect("stdout is not utf8! need to handle arbitrary bytes"),
+                std::str::from_utf8(&output.stderr)
+                    .expect("stderr is not utf8! need to handle arbitrary bytes")
+            );
+        }
+        Ok(())
+    }
+}