[Interpreter] Add support for JS calls.

src/compiler/x64/instruction-selector-x64.cc

Index: src/compiler/x64/instruction-selector-x64.cc
diff --git a/src/compiler/x64/instruction-selector-x64.cc b/src/compiler/x64/instruction-selector-x64.cc
index fa63138f2799841c5af49c2ac93a7493541881cb..40ac86e7a9b9b64bb4a519efd46bb813cd90aeae 100644
--- a/src/compiler/x64/instruction-selector-x64.cc
+++ b/src/compiler/x64/instruction-selector-x64.cc
@@ -1201,6 +1201,51 @@ void InstructionSelector::VisitTailCall(Node* node) {
 }
 
 
+void InstructionSelector::VisitCallVarArgs(Node* node) {
+  X64OperandGenerator g(this);
+  const CallDescriptor* descriptor = OpParameter<const CallDescriptor*>(node);
+  const int descriptor_input_count = static_cast<int>(descriptor->InputCount());
+
+  FrameStateDescriptor* frame_state_descriptor = nullptr;
+  if (descriptor->NeedsFrameState()) {
+    frame_state_descriptor =
+        GetFrameStateDescriptor(node->InputAt(descriptor_input_count + 2));
+  }
+
+  CallBuffer buffer(zone(), descriptor, frame_state_descriptor);
+
+  // Compute InstructionOperands for inputs and outputs.
+  InitializeCallBuffer(node, &buffer, true, true);
+
+  // Push the arguments onto the stack.
+  Node* args_start = node->InputAt(descriptor_input_count);
+  Node* args_end = node->InputAt(descriptor_input_count + 1);
+  Emit(kX64PushMultiple, g.NoOutput(), g.UseRegister(args_start),

[Benedikt Meurer, 2015/09/07 05:14:30]

Mhm, I have mixed feelings with this, but on the other hand I cannot think of a
better solution.

+       g.UseRegister(args_end));
+
+  // Select the appropriate opcode based on the call type.
+  CallDescriptor::Flags flags = descriptor->flags();
+  InstructionCode opcode;
+  switch (descriptor->kind()) {
+    case CallDescriptor::kCallCodeObject:
+      opcode = kArchCallCodeObject | MiscField::encode(flags);
+      break;
+    case CallDescriptor::kCallJSFunction:
+      opcode = kArchCallJSFunction | MiscField::encode(flags);
+      break;
+    default:
+      UNREACHABLE();
+      return;
+  }
+
+  // Emit the call instruction.
+  size_t const output_count = buffer.outputs.size();
+  auto* outputs = output_count ? &buffer.outputs.front() : nullptr;
+  Emit(opcode, output_count, outputs, buffer.instruction_args.size(),
+       &buffer.instruction_args.front())->MarkAsCall();
+}
+
+
 namespace {
 
 // Shared routine for multiple compare operations.