Merge pull request #5333 from roc-lang/wasm-flow

Fix misc wasm compilation issues

crates/cli/src/lib.rs

@@ -359,6 +359,20 @@ pub enum FormatMode {
     CheckOnly,
 }
 
+fn opt_level_from_flags(matches: &ArgMatches) -> OptLevel {
+    match (
+        matches.is_present(FLAG_OPTIMIZE),
+        matches.is_present(FLAG_OPT_SIZE),
+        matches.is_present(FLAG_DEV),
+    ) {
+        (true, false, false) => OptLevel::Optimize,
+        (false, true, false) => OptLevel::Size,
+        (false, false, true) => OptLevel::Development,
+        (false, false, false) => OptLevel::Normal,
+        _ => user_error!("build can be only one of `--dev`, `--optimize`, or `--opt-size`"),
+    }
+}
+
 #[cfg(windows)]
 pub fn test(_matches: &ArgMatches, _triple: Triple) -> io::Result<i32> {
     todo!("running tests does not work on windows right now")
@@ -374,17 +388,7 @@ pub fn test(matches: &ArgMatches, triple: Triple) -> io::Result<i32> {
     let start_time = Instant::now();
     let arena = Bump::new();
     let filename = matches.value_of_os(ROC_FILE).unwrap();
-    let opt_level = match (
-        matches.is_present(FLAG_OPTIMIZE),
-        matches.is_present(FLAG_OPT_SIZE),
-        matches.is_present(FLAG_DEV),
-    ) {
-        (true, false, false) => OptLevel::Optimize,
-        (false, true, false) => OptLevel::Size,
-        (false, false, true) => OptLevel::Development,
-        (false, false, false) => OptLevel::Normal,
-        _ => user_error!("build can be only one of `--dev`, `--optimize`, or `--opt-size`"),
-    };
+    let opt_level = opt_level_from_flags(matches);
 
     let threading = match matches
         .value_of(FLAG_MAX_THREADS)
@@ -603,35 +607,24 @@ pub fn build(
     let opt_level = if let BuildConfig::BuildAndRunIfNoErrors = config {
         OptLevel::Development
     } else {
-        match (
-            matches.is_present(FLAG_OPTIMIZE),
-            matches.is_present(FLAG_OPT_SIZE),
-        ) {
-            (true, false) => OptLevel::Optimize,
-            (false, true) => OptLevel::Size,
-            (false, false) => OptLevel::Normal,
-            (true, true) => {
-                user_error!("build can be only one of `--optimize` and `--opt-size`")
-            }
-        }
+        opt_level_from_flags(matches)
     };
 
-    let code_gen_backend = if matches!(triple.architecture, Architecture::Wasm32) {
-        CodeGenBackend::Wasm
-    } else {
-        match matches.is_present(FLAG_DEV) {
-            true => CodeGenBackend::Assembly,
-            false => {
-                let backend_mode = match opt_level {
-                    OptLevel::Development => LlvmBackendMode::BinaryDev,
-                    OptLevel::Normal | OptLevel::Size | OptLevel::Optimize => {
-                        LlvmBackendMode::Binary
-                    }
-                };
-
-                CodeGenBackend::Llvm(backend_mode)
-            }
+    // Note: This allows using `--dev` with `--optimize`.
+    // This means frontend optimizations and dev backend.
+    let code_gen_backend = if matches.is_present(FLAG_DEV) {
+        if matches!(triple.architecture, Architecture::Wasm32) {
+            CodeGenBackend::Wasm
+        } else {
+            CodeGenBackend::Assembly
         }
+    } else {
+        let backend_mode = match opt_level {
+            OptLevel::Development => LlvmBackendMode::BinaryDev,
+            OptLevel::Normal | OptLevel::Size | OptLevel::Optimize => LlvmBackendMode::Binary,
+        };
+
+        CodeGenBackend::Llvm(backend_mode)
     };
 
     let emit_debug_info = matches.is_present(FLAG_DEBUG);
@@ -647,8 +640,7 @@ pub fn build(
         Some(n) => Threading::AtMost(n),
     };
 
-    let wasm_dev_backend = matches!(opt_level, OptLevel::Development)
-        && matches!(code_gen_backend, CodeGenBackend::Wasm);
+    let wasm_dev_backend = matches!(code_gen_backend, CodeGenBackend::Wasm);
 
     let linking_strategy = if wasm_dev_backend {
         LinkingStrategy::Additive

crates/compiler/build/src/link.rs

@@ -362,21 +362,8 @@ pub fn build_zig_host_wasm32(
         unimplemented!("Linking a shared library to wasm not yet implemented");
     }
 
-    let zig_target = if matches!(opt_level, OptLevel::Development) {
-        "wasm32-wasi"
-    } else {
-        // For LLVM backend wasm we are emitting a .bc file anyway so this target is OK
-        "i386-linux-musl"
-    };
-
     // NOTE currently just to get compiler warnings if the host code is invalid.
     // the produced artifact is not used
-    //
-    // NOTE we're emitting LLVM IR here (again, it is not actually used)
-    //
-    // we'd like to compile with `-target wasm32-wasi` but that is blocked on
-    //
-    // https://github.com/ziglang/zig/issues/9414
     let mut zig_cmd = zig();
 
     zig_cmd
@@ -397,7 +384,7 @@ pub fn build_zig_host_wasm32(
             "--library",
             "c",
             "-target",
-            zig_target,
+            "wasm32-wasi",
             // "-femit-llvm-ir=/home/folkertdev/roc/roc/crates/cli_testing_examples/benchmarks/platform/host.ll",
             "-fPIC",
             "--strip",
@@ -1280,8 +1267,6 @@ fn link_wasm32(
     input_paths: &[&str],
     _link_type: LinkType,
 ) -> io::Result<(Child, PathBuf)> {
-    let wasi_libc_path = find_wasi_libc_path();
-
     let child = zig()
         // .env_clear()
         // .env("PATH", &env_path)
@@ -1289,8 +1274,9 @@ fn link_wasm32(
         .args(input_paths)
         .args([
             // include wasi libc
+            // TOOD: This now compiles fine with `-lc`. That said, the output file doesn't work.
             // using `-lc` is broken in zig 8 (and early 9) in combination with ReleaseSmall
-            wasi_libc_path.to_str().unwrap(),
+            find_wasi_libc_path().to_str().unwrap(),
             &format!("-femit-bin={}", output_path.to_str().unwrap()),
             "-target",
             "wasm32-wasi-musl",

crates/compiler/build/src/program.rs

@@ -103,7 +103,7 @@ pub fn gen_from_mono_module<'a>(
     let opt = code_gen_options.opt_level;
 
     match code_gen_options.backend {
-        CodeGenBackend::Assembly => gen_from_mono_module_dev(
+        CodeGenBackend::Assembly | CodeGenBackend::Wasm => gen_from_mono_module_dev(
             arena,
             loaded,
             target,
@@ -113,16 +113,6 @@ pub fn gen_from_mono_module<'a>(
         CodeGenBackend::Llvm(backend_mode) => {
             gen_from_mono_module_llvm(arena, loaded, path, target, opt, backend_mode, debug)
         }
-        CodeGenBackend::Wasm => {
-            // emit wasm via the llvm backend
-
-            let backend_mode = match code_gen_options.opt_level {
-                OptLevel::Development => LlvmBackendMode::BinaryDev,
-                OptLevel::Normal | OptLevel::Size | OptLevel::Optimize => LlvmBackendMode::Binary,
-            };
-
-            gen_from_mono_module_llvm(arena, loaded, path, target, opt, backend_mode, debug)
-        }
     }
 }
 
@@ -966,9 +956,17 @@ fn build_loaded_file<'a>(
             std::fs::write(&output_exe_path, &*roc_app_bytes).unwrap();
         }
         (LinkingStrategy::Legacy, _) => {
+            let extension = if matches!(operating_system, roc_target::OperatingSystem::Wasi) {
+                // Legacy linker is only by used llvm wasm backend, not dev.
+                // llvm wasm backend directly emits a bitcode file when targeting wasi, not a `.o` or `.wasm` file.
+                // If we set the extension wrong, zig will print a ton of warnings when linking.
+                "bc"
+            } else {
+                operating_system.object_file_ext()
+            };
             let app_o_file = tempfile::Builder::new()
                 .prefix("roc_app")
-                .suffix(&format!(".{}", operating_system.object_file_ext()))
+                .suffix(&format!(".{}", extension))
                 .tempfile()
                 .map_err(|err| todo!("TODO Gracefully handle tempfile creation error {:?}", err))?;
             let app_o_file = app_o_file.path();

crates/compiler/roc_target/src/lib.rs

@@ -29,7 +29,7 @@ impl OperatingSystem {
         match self {
             OperatingSystem::Windows => "obj",
             OperatingSystem::Unix => "o",
-            OperatingSystem::Wasi => "o",
+            OperatingSystem::Wasi => "wasm",
         }
     }
 

examples/platform-switching/web-assembly-platform/host.zig

@@ -49,7 +49,7 @@ pub fn main() u8 {
     roc__mainForHost_1_exposed(&callresult);
 
     // display the result using JavaScript
-    js_display_roc_string(callresult.asU8ptr(), callresult.len());
+    js_display_roc_string(callresult.asU8ptrMut(), callresult.len());
 
     callresult.decref();