[V8][Wasm] Wasm throws.

src/compiler/wasm-compiler.cc

Index: src/compiler/wasm-compiler.cc
diff --git a/src/compiler/wasm-compiler.cc b/src/compiler/wasm-compiler.cc
index f9620ac34939f6de8b4464b4b72920a2def7bdef..95a3ac84ab769ac7c9bc8b9f5e93f532a7aa9efb 100644
--- a/src/compiler/wasm-compiler.cc
+++ b/src/compiler/wasm-compiler.cc
@@ -1703,6 +1703,24 @@ Node* WasmGraphBuilder::GrowMemory(Node* input) {
   return result;
 }
 
+Node* WasmGraphBuilder::Throw(Node* input) {
+  MachineOperatorBuilder* machine = jsgraph()->machine();
+
+  // Pass the thrown value as two SMIs:

[titzer, 2016/09/15 12:53:28]

Please leave a TODO here, since I think we all agreed this was sad :(

[John, 2016/09/15 14:03:08]

Done.

+  //
+  // upper = static_cast<uint32_t>(input) >> 16;
+  // lower = input & 0xFFFF;
+  Node* upper = BuildChangeInt32ToSmi(
+      graph()->NewNode(machine->Word32Shr(), input, Int32Constant(16)));
+  Node* lower = BuildChangeInt32ToSmi(
+      graph()->NewNode(machine->Word32And(), input, Int32Constant(0xFFFFu)));
+
+  Node* parameters[] = {lower, upper};  // thrown value
+  return BuildCallToRuntime(Runtime::kWasmThrow, jsgraph(),
+                            module_->instance->context, parameters,
+                            arraysize(parameters), effect_, *control_);
+}
+
 Node* WasmGraphBuilder::BuildI32DivS(Node* left, Node* right,
                                      wasm::WasmCodePosition position) {
   MachineOperatorBuilder* m = jsgraph()->machine();