Fix memory (#45)

* better observability

* load is the culprit

* little-endian

benchmarks/wasm/btree/2o1u-no-label-for-real.wat → benchmarks/wasm/btree/2o1u-unlabeled.wat

@@ -479,7 +479,7 @@
       i32.store offset=4
     end)
   (func (;3;) (type 2) (param i32 i32)
-    (local i32)
+    (local i32 i32)
     local.get 0
     i32.load offset=4
     i32.const 1
@@ -2631,5 +2631,5 @@
     i32.const 1
     call 6)
   (memory (;0;) 2)
-  (export "main" (func 6))
+  (export "main" (func 7))
   (start 7))

benchmarks/wasm/btree/2o1u.wat

@@ -1,4 +1,5 @@
 (module
+  ;; (import "env" "log" (func $log (param i32)))
   (memory $0 2)
   (func $createBtree (param i32) (result i32) ;; createBtree(t), where t: degree of the btree
         (i32.const 0)
@@ -519,7 +520,7 @@
           )
         )
   ;; btreeInsertNonFull(x, k), where x: addr of a non full internal node; k: the key to insert
-  (func $btreeInsertNonFull (param i32) (param i32) (local i32)
+  (func $btreeInsertNonFull (param i32) (param i32) (local i32) (local $tmp i32)
         (local.get 0)     ;; x
         (i32.load offset=4)   ;; x.n
         (i32.const 1)
@@ -2809,13 +2810,12 @@
         (i32.and)
         (drop)
         )
-  (export "main" (func $main))
+  (export "main" (func $real_main))
   (func $real_main
-    i32.const 1
+    i32.const 3
     i32.const 2
     i32.const 1
     call $main
   )
   (start $real_main)
-  (start $real_main)
-  )
+)

benchmarks/wasm/btree/start.js

@@ -0,0 +1,19 @@
+const fs = require("fs");
+
+async function main() {
+  const bytes = fs.readFileSync("2o1u.wasm");
+  const env = { log: val => console.log(`logged ${val}`), };
+  const { instance } = await WebAssembly.instantiate(
+    bytes,
+    {
+      env: {
+        log(val) {
+          console.log(`log saw ${val}`);
+        }
+      }
+    }
+  );
+  instance.exports.real_main();
+  console.log(`finished`);
+}
+main();

benchmarks/wasm/load.wat

@@ -0,0 +1,19 @@
+(module
+  (type (;0;) (func (result i32)))
+  (type (;1;) (func))
+  (func (;0;) (type 0) (result i32)
+    i32.const 0
+    i32.const 1
+    i32.store 
+    i32.const 0
+    i32.load
+  )
+  (func (;1;) (type 1)
+    call 0
+    ;; should be 65536
+    ;; drop
+    )
+  (start 1)
+  (memory (;0;) 2)
+  (export "main" (func 1))
+)

src/main/scala/wasm/Memory.scala

@@ -33,7 +33,7 @@ case class RTMemory(var memType: RTMemoryType, data: ArrayBuffer[Byte]) {
   def loadn(a: Long, o: Int, n: Int): Long = {
     assert(n > 0 && n <= 8)
     var result: Long = 0
-    for (i <- 0 until n) {
+    for (i <- (n - 1) to 0 by -1) { // Little-endian: start from least significant byte
       result = (result << 8) | (loadByte(a + i) & 0xff)
     }
     result
@@ -43,7 +43,7 @@ case class RTMemory(var memType: RTMemoryType, data: ArrayBuffer[Byte]) {
     assert(n > 0 && n <= 8)
     var temp = x
     for (i <- 0 until n) {
-      storeByte(a + i, (temp & 0xff).toByte)
+      storeByte(a + i, (temp & 0xff).toByte) // Little-endian: store least significant byte first
       temp = temp >> 8
     }
   }

src/main/scala/wasm/MiniWasm.scala

@@ -181,8 +181,8 @@ object Evaluator {
     val inst = insts.head
     val rest = insts.tail
 
-    //println(f"stack size: ${stack.size}")
-    //println(s"eval: $inst")
+    // println(s"inst: ${inst} \t | ${frame.locals} | ${stack.reverse}" )
+
     inst match {
       case Drop => eval(rest, stack.tail, frame, kont, trail, ret)
       case Select(_) =>

src/test/scala/genwasym/TestEval.scala

@@ -16,7 +16,9 @@ import org.scalatest.FunSuite
 class TestEval extends FunSuite {
 
   // Mostly testing the files generated form `benchmarks/wasm/test.rs`
-  def testFile(filename: String, main: Option[String] = None, expected: Option[Int] = None) = {
+  def testFile(filename: String,
+               main: Option[String] = None,
+               expected: Option[Int] = None) = {
     val module = Parser.parseFile(filename)
     //println(module)
     val haltK: Evaluator.Cont[Unit] = stack => {
@@ -39,12 +41,9 @@ class TestEval extends FunSuite {
   test("loop") { testFile("./benchmarks/wasm/loop.wat", None, Some(10)) }
   test("even-odd") { testFile("./benchmarks/wasm/even_odd.wat", None, Some(1)) }
   test("return") { testFile("./benchmarks/wasm/return.wat", None, None) }
-
+  test("load") { testFile("./benchmarks/wasm/load.wat", None, Some(1)) }
+  test("btree") { testFile("./benchmarks/wasm/btree/2o1u-unlabeled.wat") }
   test("fib") { testFile("./benchmarks/wasm/fib.wat", None, Some(144)) }
 
-  // Parser works, but the memory issue remains
-  // test("btree") { testFile("./benchmarks/wasm/btree/2o1u-no-label-for-real.wat") }
-
-  // TODO: add more wasm spec tests?
-  // test("memory") { test_btree("./benchmarks/wasm/spectest/test.wat", "$real_main") }
+  // TODO: add wasm spec tests? How to utilize wast files?
 }