Add some debug features to gen_wasm

compiler/gen_wasm/src/backend.rs

@@ -58,6 +58,8 @@ pub struct WasmBackend<'a> {
     /// how many blocks deep are we (used for jumps)
     block_depth: u32,
     joinpoint_label_map: MutMap<JoinPointId, (u32, Vec<'a, StoredValue>)>,
+
+    debug_current_proc_index: usize,
 }
 
 impl<'a> WasmBackend<'a> {
@@ -149,6 +151,8 @@ impl<'a> WasmBackend<'a> {
             code_builder: CodeBuilder::new(arena),
             storage: Storage::new(arena),
             symbol_layouts: MutMap::default(),
+
+            debug_current_proc_index: 0,
         }
     }
 
@@ -203,6 +207,7 @@ impl<'a> WasmBackend<'a> {
 
     pub fn build_proc(&mut self, proc: &Proc<'a>) {
         // println!("\ngenerating procedure {:?}\n", proc.name);
+        self.debug_current_proc_index += 1;
 
         self.start_proc(proc);
 
@@ -1246,4 +1251,18 @@ impl<'a> WasmBackend<'a> {
         self.code_builder
             .call(fn_index, linker_symbol_index, num_wasm_args, has_return_val);
     }
+
+    /// Debug utility
+    ///
+    /// if _debug_current_proc_is("#UserApp_foo_1") {
+    ///     self.code_builder._debug_assert_i32(0x1234);
+    /// }
+    fn _debug_current_proc_is(&self, linker_name: &'static str) -> bool {
+        let (_, linker_sym_index) = self.proc_symbols[self.debug_current_proc_index];
+        let sym_info = &self.linker_symbols[linker_sym_index as usize];
+        match sym_info {
+            SymInfo::Function(WasmObjectSymbol::Defined { name, .. }) => name == linker_name,
+            _ => false,
+        }
+    }
 }

compiler/gen_wasm/src/wasm_module/code_builder.rs

@@ -901,4 +901,17 @@ impl<'a> CodeBuilder<'a> {
     instruction_no_args!(i64_reinterpret_f64, I64REINTERPRETF64, 1, true);
     instruction_no_args!(f32_reinterpret_i32, F32REINTERPRETI32, 1, true);
     instruction_no_args!(f64_reinterpret_i64, F64REINTERPRETI64, 1, true);
+
+    /// Generate a debug assertion for an expected i32 value
+    pub fn _debug_assert_i32(&mut self, expected: i32) {
+        self.i32_const(expected);
+        self.i32_eq();
+        self.i32_eqz();
+        self.if_(BlockType::NoResult);
+        self.unreachable_(); // Tell Wasm runtime to throw an exception
+        self.end();
+        // It matches. Restore the original value to the VM stack and continue the program.
+        // We know it matched the expected value, so just use that!
+        self.i32_const(expected);
+    }
 }

compiler/test_gen/src/helpers/wasm.rs

@@ -247,10 +247,16 @@ where
                 _ => panic!(),
             };
 
-            if false {
+            if true {
+                println!("test_wrapper returned 0x{:x}", address);
+                println!("Stack:");
                 crate::helpers::wasm::debug_memory_hex(memory, address, std::mem::size_of::<T>());
             }
-
+            if true {
+                println!("Heap:");
+                // Manually provide address and size based on printf in test_platform.c
+                crate::helpers::wasm::debug_memory_hex(memory, 0x11440, 24);
+            }
             let output = <T as FromWasm32Memory>::decode(memory, address as u32);
 
             Ok(output)
@@ -267,12 +273,17 @@ pub fn debug_memory_hex(memory: &Memory, address: i32, size: usize) {
     };
 
     let extra_words = 2;
-    let offset = (address as usize) / 4;
+    let result_start = (address as usize) / 4;
-    let start = offset - extra_words;
+    let result_end = result_start + ((size + 3) / 4);
-    let end = offset + (size / 4) + extra_words;
+    let start = result_start - extra_words;
+    let end = result_end + extra_words;
 
     for index in start..end {
-        let result_marker = if index == offset { "*" } else { " " };
+        let result_marker = if index >= result_start && index < result_end {
+            "|"
+        } else {
+            " "
+        };
         println!(
             "{:x} {} {:08x}",
             index * 4,
@@ -280,6 +291,7 @@ pub fn debug_memory_hex(memory: &Memory, address: i32, size: usize) {
             memory_words[index]
         );
     }
+    println!();
 }
 
 #[allow(unused_macros)]

compiler/test_gen/src/helpers/wasm_test_platform.c

@@ -3,7 +3,18 @@
 // If any printf is included for compilation, even if unused, test runs take 50% longer
 #define DEBUG 0
 
-void *roc_alloc(size_t size, unsigned int alignment) { return malloc(size); }
+void *roc_alloc(size_t size, unsigned int alignment)
+{
+    void *allocated = malloc(size);
+    if (!allocated)
+    {
+        fprintf(stderr, "roc_alloc failed\n");
+        exit(1);
+    } else {
+        printf("roc_alloc allocated %d bytes at %p\n", size, allocated);
+    }
+    return allocated;
+}
 
 void *roc_realloc(void *ptr, size_t new_size, size_t old_size,
                   unsigned int alignment)