interpreter: signed-extend to 32-bit in SignExtend32 (#701)

Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>

internal/engine/interpreter/interpreter.go

@@ -1785,11 +1785,11 @@ func (ce *callEngine) callNativeFunc(ctx context.Context, callCtx *wasm.CallCont
 			}
 			frame.pc++
 		case wazeroir.OperationKindSignExtend32From8:
-			v := int32(int8(ce.popValue()))
+			v := uint32(int8(ce.popValue()))
 			ce.pushValue(uint64(v))
 			frame.pc++
 		case wazeroir.OperationKindSignExtend32From16:
-			v := int32(int16(ce.popValue()))
+			v := uint32(int16(ce.popValue()))
 			ce.pushValue(uint64(v))
 			frame.pc++
 		case wazeroir.OperationKindSignExtend64From8:

internal/integration_test/fuzzcases/fuzzcases_test.go

@@ -19,6 +19,8 @@ var (
 	case696 []byte
 	//go:embed testdata/699.wasm
 	case699 []byte
+	//go:embed testdata/701.wasm
+	case701 []byte
 )
 
 func newRuntimeCompiler() wazero.Runtime {
@@ -112,3 +114,31 @@ func Test699(t *testing.T) {
 		})
 	}
 }
+
+// Test701 requires two functions to exit with "out of bounds memory access" consistently across the implementations.
+func Test701(t *testing.T) {
+	if !platform.CompilerSupported() {
+		return
+	}
+
+	for _, tc := range []struct {
+		name string
+		r    wazero.Runtime
+	}{
+		{name: "compiler", r: newRuntimeCompiler()},
+		{name: "interpreter", r: newRuntimeInterpreter()},
+	} {
+		tc := tc
+		t.Run(tc.name, func(t *testing.T) {
+			defer tc.r.Close(ctx)
+			module, err := tc.r.InstantiateModuleFromBinary(ctx, case701)
+			require.NoError(t, err)
+
+			_, err = module.ExportedFunction("i32.extend16_s").Call(ctx)
+			require.Contains(t, err.Error(), "out of bounds memory access")
+
+			_, err = module.ExportedFunction("i32.extend8_s").Call(ctx)
+			require.Contains(t, err.Error(), "out of bounds memory access")
+		})
+	}
+}

internal/integration_test/fuzzcases/testdata/701.wat

@@ -0,0 +1,19 @@
+(module
+  (func (export "i32.extend16_s")
+    i32.const 0xffff
+    ;; if this extends to 64 bit, the bit pattern of the value has all bits set
+    i32.extend16_s
+    ;; then plus one to it results in zero offset.
+    v128.load16x4_u offset=1 align=1
+    unreachable
+  )
+  (func (export "i32.extend8_s")
+    i32.const 0xff
+    ;; if this extends to 64 bit, the bit pattern of the value has all bits set
+    i32.extend8_s
+    ;; then plus one to it results in zero offset.
+    v128.load16x4_u offset=1 align=1
+    unreachable
+  )
+  (memory 1 1)
+)