1 files changed, 197 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/wasm/gc/br-on-cast.js b/js/src/jit-test/tests/wasm/gc/br-on-cast.js
new file mode 100644
index 0000000000..cf83f1ba00
--- /dev/null
+++ b/js/src/jit-test/tests/wasm/gc/br-on-cast.js
@@ -0,0 +1,197 @@
+// |jit-test| skip-if: !wasmGcEnabled()
+
+function typingModule(types, from, to, brParams, branchResults, fallthroughResults) {
+  return `(module
+    ${types}
+    (func
+      (param ${brParams.join(' ')})
+      (result ${branchResults.join(' ')})
+
+      (block (result ${fallthroughResults.join(' ')})
+        (; push params onto the stack in the same order as they appear, leaving
+          the last param at the top of the stack. ;)
+        ${brParams.map((_, i) => `local.get ${i}`).join('\n')}
+        br_on_cast 1 ${from} ${to}
+      )
+      unreachable
+    )
+  )`;
+}
+
+function validTyping(types, from, to, brParams, branchResults, fallthroughResults) {
+  wasmValidateText(typingModule(types, from, to, brParams, branchResults, fallthroughResults));
+}
+
+function invalidTyping(types, from, to, brParams, branchResults, fallthroughResults, error) {
+  wasmFailValidateText(typingModule(types, from, to, brParams, branchResults, fallthroughResults), error);
+}
+
+// valid: eqref -> struct
+validTyping('(type $a (struct))', 'eqref', '(ref $a)', ['eqref'], ['(ref $a)'], ['eqref']);
+// valid: eqref -> struct (and looser types on results)
+validTyping('(type $a (struct))', 'eqref', '(ref $a)', ['eqref'], ['(ref null $a)'], ['anyref']);
+// valid: eqref -> nullable struct (note that fallthrough becomes non-nullable)
+validTyping('(type $a (struct))', 'eqref', '(ref null $a)', ['eqref'], ['(ref null $a)'], ['(ref eq)']);
+// valid: struct -> struct (from anyref)
+validTyping('(type $a (struct))', 'anyref', '(ref $a)', ['(ref $a)'], ['(ref $a)'], ['anyref']);
+// valid: struct -> struct (canonicalized)
+validTyping('(type $a (struct)) (type $b (struct))', '(ref $a)', '(ref $b)', ['(ref $a)'], ['(ref $b)'], ['(ref $b)']);
+// valid: nullable struct -> non-nullable struct (canonicalized)
+validTyping('(type $a (struct)) (type $b (struct))', '(ref null $a)', '(ref $b)', ['(ref null $a)'], ['(ref $b)'], ['(ref null $a)']);
+// valid: nullable struct -> nullable struct (canonicalized)
+validTyping('(type $a (struct)) (type $b (struct))', '(ref null $a)', '(ref null $b)', ['(ref null $a)'], ['(ref null $a)'], ['(ref $a)']);
+// valid: eqref -> struct with extra arg
+validTyping('(type $a (struct))', 'eqref', '(ref $a)', ['i32', 'eqref'], ['i32', '(ref $a)'], ['i32', 'eqref']);
+// valid: eqref -> struct with two extra args
+validTyping('(type $a (struct))', 'eqref', '(ref $a)', ['i32', 'f32', 'eqref'], ['i32', 'f32', '(ref $a)'], ['i32', 'f32', 'eqref']);
+
+// invalid: block result type must have slot for casted-to type
+invalidTyping('(type $a (struct))', 'eqref', '(ref $a)', ['eqref'], [], ['eqref'], /type mismatch/);
+// invalid: block result type must be supertype of casted-to type
+invalidTyping('(type $a (struct)) (type $b (struct (field i32)))', 'eqref', '(ref $a)', ['eqref'], ['(ref $b)'], ['(ref $a)'], /type mismatch/);
+// invalid: input is missing extra i32 from the branch target type
+invalidTyping('(type $a (struct))', 'eqref', '(ref $a)', ['f32', 'eqref'], ['i32', 'f32', '(ref $a)'], ['i32', 'f32', 'eqref'], /popping value/);
+// invalid: input has extra [i32, f32] swapped from the branch target type
+invalidTyping('(type $a (struct))', 'eqref', '(ref $a)', ['i32', 'f32', 'eqref'], ['f32', 'i32', '(ref $a)'], ['i32', 'f32', 'eqref'], /type mismatch/);
+// invalid: input has extra [i32, f32] swapped from the branch fallthrough type
+invalidTyping('(type $a (struct))', 'eqref', '(ref $a)', ['i32', 'f32', 'eqref'], ['i32', 'f32', '(ref $a)'], ['f32', 'i32', 'eqref'], /type mismatch/);
+// invalid: casting to non-nullable but fallthrough not nullable
+invalidTyping('(type $a (struct))', 'eqref', '(ref $a)', ['eqref'], ['(ref $a)'], ['(ref eq)'], /type mismatch/);
+// invalid: struct -> struct (same recursion group)
+invalidTyping('(rec (type $a (struct)) (type $b (struct)))', '(ref $a)', '(ref $b)', ['(ref $a)'], ['(ref $b)'], ['(ref $a)'], /type mismatch/);
+
+// Simple runtime test of casting
+{
+  let { makeA, makeB, isA, isB } = wasmEvalText(`(module
+    (type $a (struct))
+    (type $b (sub $a (struct (field i32))))
+
+    (func (export "makeA") (result eqref)
+      struct.new_default $a
+    )
+
+    (func (export "makeB") (result eqref)
+      struct.new_default $b
+    )
+
+    (func (export "isA") (param eqref) (result i32)
+      (block (result (ref $a))
+        local.get 0
+        br_on_cast 0 anyref (ref $a)
+
+        i32.const 0
+        br 1
+      )
+      drop
+      i32.const 1
+    )
+
+    (func (export "isB") (param eqref) (result i32)
+      (block (result (ref $a))
+        local.get 0
+        br_on_cast 0 anyref (ref $b)
+
+        i32.const 0
+        br 1
+      )
+      drop
+      i32.const 1
+    )
+  )`).exports;
+
+  let a = makeA();
+  let b = makeB();
+
+  assertEq(isA(a), 1);
+  assertEq(isA(b), 1);
+  assertEq(isB(a), 0);
+  assertEq(isB(b), 1);
+}
+
+// Runtime test of casting with extra values
+{
+  function assertEqResults(a, b) {
+    if (!(a instanceof Array)) {
+      a = [a];
+    }
+    if (!(b instanceof Array)) {
+      b = [b];
+    }
+    if (a.length !== b.length) {
+      assertEq(a.length, b.length);
+    }
+    for (let i = 0; i < a.length; i++) {
+      let x = a[i];
+      let y = b[i];
+      // intentionally use loose equality to allow bigint to compare equally
+      // to number, as can happen with how we use the JS-API here.
+      assertEq(x == y, true);
+    }
+  }
+
+  function testExtra(values) {
+    let { makeT, makeF, select } = wasmEvalText(`(module
+      (type $t (struct))
+      (type $f (struct (field i32)))
+
+      (func (export "makeT") (result eqref)
+        struct.new_default $t
+      )
+      (func (export "makeF") (result eqref)
+        struct.new_default $f
+      )
+
+      (func (export "select") (param eqref) (result ${values.map((type) => type).join(" ")})
+        (block (result (ref $t))
+          local.get 0
+          br_on_cast 0 anyref (ref $t)
+
+          ${values.map((type, i) => `${type}.const ${values.length + i}`).join("\n")}
+          br 1
+        )
+        drop
+        ${values.map((type, i) => `${type}.const ${i}`).join("\n")}
+      )
+    )`).exports;
+
+    let t = makeT();
+    let f = makeF();
+
+    let trueValues = values.map((type, i) => i);
+    let falseValues = values.map((type, i) => values.length + i);
+
+    assertEqResults(select(t), trueValues);
+    assertEqResults(select(f), falseValues);
+  }
+
+  // multiples of primitive valtypes
+  for (let valtype of ['i32', 'i64', 'f32', 'f64']) {
+    testExtra([valtype]);
+    testExtra([valtype, valtype]);
+    testExtra([valtype, valtype, valtype]);
+    testExtra([valtype, valtype, valtype, valtype, valtype, valtype, valtype, valtype]);
+  }
+
+  // random sundry of valtypes
+  testExtra(['i32', 'f32', 'i64', 'f64']);
+  testExtra(['i32', 'f32', 'i64', 'f64', 'i32', 'f32', 'i64', 'f64']);
+}
+
+// This test causes the `values` vector returned by
+// `OpIter<Policy>::readBrOnCast` to contain three entries, the last of which
+// is the argument, hence is reftyped.  This is used to verify an assertion to
+// that effect in FunctionCompiler::brOnCastCommon.
+{
+    let tOnCast =
+    `(module
+       (type $a (struct))
+       (func (export "onCast") (param f32 i32 eqref) (result f32 i32 (ref $a))
+         local.get 0
+         local.get 1
+         local.get 2
+         br_on_cast 0 anyref (ref $a)
+         unreachable
+       )
+     )`;
+    let { onCast } = wasmEvalText(tOnCast).exports;
+}