Support inlining of calls where type arguments are passed to generic functions.

runtime/vm/flow_graph_type_propagator.cc

Index: runtime/vm/flow_graph_type_propagator.cc
diff --git a/runtime/vm/flow_graph_type_propagator.cc b/runtime/vm/flow_graph_type_propagator.cc
index fe3f74222035aec52e969c3e02d3af13226a1ca3..20203ae7805ca11d98799fb95df0b10a08984de8 100644
--- a/runtime/vm/flow_graph_type_propagator.cc
+++ b/runtime/vm/flow_graph_type_propagator.cc
@@ -980,9 +980,19 @@ CompileType RelationalOpInstr::ComputeType() const {
 }
 
 
-CompileType CurrentContextInstr::ComputeType() const {
-  return CompileType(CompileType::kNonNullable, kContextCid,
-                     &Object::dynamic_type());
+CompileType SpecialParameterInstr::ComputeType() const {
+  intptr_t cid = kIllegalCid;
+  switch (kind()) {

[Vyacheslav Egorov (Google), 2017/07/06 10:31:57]

I would structure this a bit differently:

  switch (kind()) {
    case kContext: return CompileType::FromCid(kContextCid);
    case kTypeArguments: return CompileType::FromCid(kTypeArgumentsCid);
  }
  UNREACHABLE();
  return CompileType::Dynamic();

The reason for that is that having default: disables compile time checking for
exhaustiveness of the switch - which was my primary reason for recommending the
switch. 

[regis, 2017/07/06 19:03:25]

Done.

+    case kContext:
+      cid = kContextCid;
+      break;
+    case kTypeArgs:
+      cid = kTypeArgumentsCid;
+      break;
+    default:
+      UNREACHABLE();
+  }
+  return CompileType(CompileType::kNonNullable, cid, &Object::dynamic_type());
 }