1 files changed, 70 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/dataview/write-unaligned.js b/js/src/jit-test/tests/dataview/write-unaligned.js
new file mode 100644
index 0000000000..e8d0b262f4
--- /dev/null
+++ b/js/src/jit-test/tests/dataview/write-unaligned.js
@@ -0,0 +1,70 @@
+// Test unaligned write access.
+
+load(libdir + "dataview.js");
+
+// Create a new test function for each scalar type.
+function createWrite(data) {
+  const name = typeName(data.type);
+  const offset = 1;
+
+  return Function("data", `
+    const {values, littleEndian, bigEndian} = data;
+
+    // Load from array so that Ion doesn't treat as constants.
+    const True = [true, 1];
+    const False = [false, 0];
+
+    const src = new ${data.type.name}(values);
+
+    const ab = new ArrayBuffer(${data.type.BYTES_PER_ELEMENT + offset});
+    const dv = new DataView(ab);
+
+    const srcUint8 = new Uint8Array(src.buffer);
+    const dstUint8 = new Uint8Array(ab);
+
+    function assertSameContents(idx, msg) {
+      for (let i = 0; i < ${data.type.BYTES_PER_ELEMENT}; ++i) {
+        assertEq(dstUint8[i + ${offset}], srcUint8[i + idx * ${data.type.BYTES_PER_ELEMENT}]);
+      }
+    }
+
+    for (let i = 0; i < 100; ++i) {
+      let j = i % values.length;
+
+      // Skip over NaNs to avoid false-negatives due to NaN canonicalisation.
+      if (${name === "Float32" || name === "Float64"}) {
+        if (Number.isNaN(bigEndian[j]) || Number.isNaN(littleEndian[j])) {
+          continue;
+        }
+      }
+
+      dstUint8.fill(0);
+      dv.set${name}(${offset}, bigEndian[j]);
+      assertSameContents(j, "default");
+
+      dstUint8.fill(0);
+      dv.set${name}(${offset}, littleEndian[j], true);
+      assertSameContents(j, "little");
+
+      dstUint8.fill(0);
+      dv.set${name}(${offset}, bigEndian[j], false);
+      assertSameContents(j, "big");
+
+      dstUint8.fill(0);
+      dv.set${name}(${offset}, littleEndian[j], True[i & 1]);
+      assertSameContents(j, "little, dynamic");
+
+      dstUint8.fill(0);
+      dv.set${name}(${offset}, bigEndian[j], False[i & 1]);
+      assertSameContents(j, "big, dynamic");
+    }
+  `);
+}
+
+for (let data of createTestData()) {
+  let f = createWrite(data);
+
+  for (let i = 0; i < 2; ++i) {
+    f(data);
+  }
+}