DBC: Eager deoptimization and CheckSmi instruction.

runtime/vm/flow_graph_compiler_dbc.cc

Index: runtime/vm/flow_graph_compiler_dbc.cc
diff --git a/runtime/vm/flow_graph_compiler_dbc.cc b/runtime/vm/flow_graph_compiler_dbc.cc
index 86352cc491b03df24cef4cc6c6dc978111bb8f21..7b0a25c6269df8c1cde57d96324bbdb1c3052469 100644
--- a/runtime/vm/flow_graph_compiler_dbc.cc
+++ b/runtime/vm/flow_graph_compiler_dbc.cc
@@ -209,7 +209,20 @@ void FlowGraphCompiler::RecordAfterCall(Instruction* instr) {
 
 void CompilerDeoptInfoWithStub::GenerateCode(FlowGraphCompiler* compiler,
                                              intptr_t stub_ix) {
-  UNIMPLEMENTED();
+  // Calls do not need stubs, they share a deoptimization trampoline.

[Vyacheslav Egorov (Google), 2016/06/08 11:58:53]

I don't think we really need DeoptInfoWithStub on DBC. At least not as much as
on other platforms. Instead of doing:

Condition 
Jump stub

We just should do 

Condition 
Deopt ... 

[zra, 2016/06/08 17:46:30]

Done.

+  ASSERT(reason() != ICData::kDeoptAtCall);
+  Assembler* assembler = compiler->assembler();
+#define __ assembler->
+  __ Comment("%s", Name());
+  __ Bind(entry_label());
+  if (FLAG_trap_on_deoptimization) {
+    __ Trap();
+  }
+
+  ASSERT(deopt_env() != NULL);
+  set_pc_offset(assembler->CodeSize());

[zra, 2016/06/07 22:31:28]

On other architectures this comes after the Deopt call. Not sure why I have to
put it in front.

+  __ Deopt(0, deopt_id());
+#undef __
 }
 
 
@@ -387,6 +400,8 @@ void FlowGraphCompiler::CompileGraph() {
 
   EmitFrameEntry();
   VisitBlocks();
+  __ Trap();
+  GenerateDeferredCode();
 }