Implement crash in gen-wasm

crates/compiler/gen_wasm/src/backend.rs

@@ -718,7 +718,7 @@ impl<'a> WasmBackend<'a> {
             Stmt::ExpectFx { .. } => todo!("expect-fx is not implemented in the wasm backend"),
 
             Stmt::RuntimeError(msg) => self.stmt_runtime_error(msg),
-            Stmt::Crash(_, _) => todo!(),
+            Stmt::Crash(sym, _) => self.stmt_crash(*sym),
         }
     }
 
@@ -1016,6 +1016,16 @@ impl<'a> WasmBackend<'a> {
         self.code_builder.unreachable_();
     }
 
+    pub fn stmt_crash(&mut self, msg: Symbol) {
+        let tag_id = 1;
+        // load the pointer
+        self.storage.load_symbols(&mut self.code_builder, &[msg]);
+        self.code_builder.i32_const(tag_id);
+        self.call_host_fn_after_loading_args("roc_panic", 2, false);
+
+        self.code_builder.unreachable_();
+    }
+
     /**********************************************************
 
             EXPRESSIONS

crates/compiler/test_gen/src/gen_panic.rs

@@ -7,7 +7,7 @@ use crate::helpers::llvm::expect_runtime_error_panic;
 use crate::helpers::wasm::expect_runtime_error_panic;
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-wasm"))]
 #[should_panic = r#"User crash with message: "hello crash""#]
 fn crash_literal() {
     expect_runtime_error_panic!(indoc!(
@@ -20,7 +20,7 @@ fn crash_literal() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-wasm"))]
 #[should_panic = r#"User crash with message: "hello crash""#]
 fn crash_variable() {
     expect_runtime_error_panic!(indoc!(
@@ -35,7 +35,7 @@ fn crash_variable() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-wasm"))]
 #[should_panic = r#"User crash with message: "turns out this was fallible""#]
 fn crash_in_call() {
     expect_runtime_error_panic!(indoc!(
@@ -55,7 +55,7 @@ fn crash_in_call() {
 }
 
 #[test]
-#[cfg(any(feature = "gen-llvm"))]
+#[cfg(any(feature = "gen-llvm", feature = "gen-wasm"))]
 #[should_panic = r#"User crash with message: "no new even primes""#]
 fn crash_in_passed_closure() {
     expect_runtime_error_panic!(indoc!(

crates/compiler/test_gen/src/helpers/wasm.rs

@@ -194,7 +194,7 @@ where
 
     let parsed = Module::parse(&env, &wasm_bytes[..]).expect("Unable to parse module");
     let mut module = rt.load_module(parsed).expect("Unable to load module");
-    let panic_msg: Rc<Mutex<Option<i32>>> = Default::default();
+    let panic_msg: Rc<Mutex<Option<(i32, u32)>>> = Default::default();
     link_module(&mut module, panic_msg.clone());
 
     let test_wrapper = module
@@ -203,11 +203,18 @@ where
 
     match test_wrapper.call() {
         Err(e) => {
-            if let Some(msg_ptr) = *panic_msg.lock().unwrap() {
+            if let Some((msg_ptr, tag)) = *panic_msg.lock().unwrap() {
                 let memory: &[u8] = get_memory(&rt);
                 let msg = RocStr::decode(memory, msg_ptr as _);
 
-                Err(format!("Roc failed with message: \"{}\"", msg))
+                dbg!(tag);
+                let msg = match tag {
+                    0 => format!(r#"Roc failed with message: "{}""#, msg),
+                    1 => format!(r#"User crash with message: "{}""#, msg),
+                    tag => format!(r#"Got an invald panic tag: "{}""#, tag),
+                };
+
+                Err(msg)
             } else {
                 Err(format!("{}", e))
             }
@@ -253,7 +260,7 @@ where
     let parsed = Module::parse(&env, wasm_bytes).expect("Unable to parse module");
     let mut module = rt.load_module(parsed).expect("Unable to load module");
 
-    let panic_msg: Rc<Mutex<Option<i32>>> = Default::default();
+    let panic_msg: Rc<Mutex<Option<(i32, u32)>>> = Default::default();
     link_module(&mut module, panic_msg.clone());
 
     let expected_len = num_refcounts as i32;
@@ -316,13 +323,13 @@ fn read_i32(memory: &[u8], ptr: usize) -> i32 {
     i32::from_le_bytes(bytes)
 }
 
-fn link_module(module: &mut Module, panic_msg: Rc<Mutex<Option<i32>>>) {
+fn link_module(module: &mut Module, panic_msg: Rc<Mutex<Option<(i32, u32)>>>) {
     let try_link_panic = module.link_closure(
         "env",
         "send_panic_msg_to_rust",
-        move |_call_context, msg_ptr: i32| {
+        move |_call_context, (msg_ptr, tag): (i32, u32)| {
             let mut w = panic_msg.lock().unwrap();
-            *w = Some(msg_ptr);
+            *w = Some((msg_ptr, tag));
             Ok(())
         },
     );

crates/compiler/test_gen/src/helpers/wasm_test_platform.c

@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -123,11 +124,11 @@ void roc_dealloc(void *ptr, unsigned int alignment)
 
 //--------------------------
 
-extern void send_panic_msg_to_rust(void* msg);
+extern void send_panic_msg_to_rust(void* msg, uint32_t tag_id);
 
 void roc_panic(void* msg, unsigned int tag_id)
 {
-    send_panic_msg_to_rust(msg);
+    send_panic_msg_to_rust(msg, tag_id);
     exit(101);
 }