Use smallest possible alignment

Co-Authored-By: Liam Murphy <[email protected]>

Author: daxpedda

crates/cli-support/src/js/binding.rs

@@ -817,14 +817,12 @@ fn instruction(js: &mut JsBuilder, instr: &Instruction, log_error: &mut bool) ->
             let func = js.cx.pass_to_wasm_function(kind.clone(), *mem)?;
             let malloc = js.cx.export_name_of(*malloc);
             let i = js.tmp();
-            let align = std::cmp::max(kind.size(), 4);
             js.prelude(&format!(
-                "const ptr{i} = {f}({0}, wasm.{malloc}, {align});",
+                "const ptr{i} = {f}({0}, wasm.{malloc});",
                 val,
                 i = i,
                 f = func,
                 malloc = malloc,
-                align = align,
             ));
             js.prelude(&format!("const len{} = WASM_VECTOR_LEN;", i));
             js.push(format!("ptr{}", i));
@@ -928,7 +926,7 @@ fn instruction(js: &mut JsBuilder, instr: &Instruction, log_error: &mut bool) ->
             let malloc = js.cx.export_name_of(*malloc);
             let val = js.pop();
             js.prelude(&format!(
-                "var ptr{i} = isLikeNone({0}) ? 0 : {f}({0}, wasm.{malloc}, 4);",
+                "var ptr{i} = isLikeNone({0}) ? 0 : {f}({0}, wasm.{malloc});",
                 val,
                 i = i,
                 f = func,
@@ -946,7 +944,7 @@ fn instruction(js: &mut JsBuilder, instr: &Instruction, log_error: &mut bool) ->
             let malloc = js.cx.export_name_of(*malloc);
             let i = js.tmp();
             js.prelude(&format!(
-                "var ptr{i} = {f}({val}, wasm.{malloc}, 4);",
+                "var ptr{i} = {f}({val}, wasm.{malloc});",
                 val = val,
                 i = i,
                 f = func,

crates/cli-support/src/js/mod.rs

@@ -1259,14 +1259,14 @@ impl<'a> Context<'a> {
             "\
                 if (realloc === undefined) {{
                     const buf = cachedTextEncoder.encode(arg);
-                    const ptr = malloc(buf.length, 4) >>> 0;
+                    const ptr = malloc(buf.length, 1) >>> 0;
                     {mem}().subarray(ptr, ptr + buf.length).set(buf);
                     WASM_VECTOR_LEN = buf.length;
                     return ptr;
                 }}
 
                 let len = arg.length;
-                let ptr = malloc(len, 4) >>> 0;
+                let ptr = malloc(len, 1) >>> 0;
 
                 const mem = {mem}();
 
@@ -1294,7 +1294,7 @@ impl<'a> Context<'a> {
                     if (offset !== 0) {{
                         arg = arg.slice(offset);
                     }}
-                    ptr = realloc(ptr, len, len = offset + arg.length * 3, 4) >>> 0;
+                    ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
                     const view = {mem}().subarray(ptr + offset, ptr + len);
                     const ret = encodeString(arg, view);
                     {debug_end}
@@ -1415,8 +1415,8 @@ impl<'a> Context<'a> {
         self.expose_wasm_vector_len();
         self.global(&format!(
             "
-            function {}(arg, malloc, align) {{
-                const ptr = malloc(arg.length * {size}, align) >>> 0;
+            function {}(arg, malloc) {{
+                const ptr = malloc(arg.length * {size}, {size}) >>> 0;
                 {}().set(arg, ptr / {size});
                 WASM_VECTOR_LEN = arg.length;
                 return ptr;

crates/cli/tests/reference/string-arg.js

@@ -47,14 +47,14 @@ function passStringToWasm0(arg, malloc, realloc) {
 
     if (realloc === undefined) {
         const buf = cachedTextEncoder.encode(arg);
-        const ptr = malloc(buf.length, 4) >>> 0;
+        const ptr = malloc(buf.length, 1) >>> 0;
         getUint8Memory0().subarray(ptr, ptr + buf.length).set(buf);
         WASM_VECTOR_LEN = buf.length;
         return ptr;
     }
 
     let len = arg.length;
-    let ptr = malloc(len, 4) >>> 0;
+    let ptr = malloc(len, 1) >>> 0;
 
     const mem = getUint8Memory0();
 
@@ -70,7 +70,7 @@ function passStringToWasm0(arg, malloc, realloc) {
         if (offset !== 0) {
             arg = arg.slice(offset);
         }
-        ptr = realloc(ptr, len, len = offset + arg.length * 3, 4) >>> 0;
+        ptr = realloc(ptr, len, len = offset + arg.length * 3, 1) >>> 0;
         const view = getUint8Memory0().subarray(ptr + offset, ptr + len);
         const ret = encodeString(arg, view);
 

crates/threads-xform/src/lib.rs

@@ -347,7 +347,7 @@ fn inject_start(
                 // local = malloc(stack.size, align) [aka base]
                 with_temp_stack(body, memory, stack, |body| {
                     body.i32_const(stack.size as i32)
-                        .i32_const(4)
+                        .i32_const(16)
                         .call(malloc)
                         .local_tee(local);
                 });
@@ -427,14 +427,14 @@ fn inject_destroy(
             // we're destroying somebody else's stack, so we can use our own
             body.local_get(stack_alloc)
                 .i32_const(stack.size as i32)
-                .i32_const(4)
+                .i32_const(16)
                 .call(free);
         },
         |body| {
             with_temp_stack(body, memory, stack, |body| {
                 body.global_get(stack.alloc)
                     .i32_const(stack.size as i32)
-                    .i32_const(4)
+                    .i32_const(16)
                     .call(free);
             });