Initial SIMDBC interpreter.

runtime/vm/flow_graph_compiler.h

Index: runtime/vm/flow_graph_compiler.h
diff --git a/runtime/vm/flow_graph_compiler.h b/runtime/vm/flow_graph_compiler.h
index 3dc31a07ce518b5f6c1f50b04a6c28d830138b35..1a1dc4d1d8a3d051809835e19ca48e01598924ed 100644
--- a/runtime/vm/flow_graph_compiler.h
+++ b/runtime/vm/flow_graph_compiler.h
@@ -367,6 +367,15 @@ class FlowGraphCompiler : public ValueObject {
   // Returns 'true' if regular code generation should be skipped.
   bool TryIntrinsify();
 
+  void GenerateAssertAssignable(TokenPosition token_pos,
+                                intptr_t deopt_id,
+                                const AbstractType& dst_type,
+                                const String& dst_name,
+                                LocationSummary* locs);
+
+  // DBC emits calls very differently from all other architectures due to its

[zra, 2016/04/14 18:27:48]

I'd leave these in and put UNREACHABLE() or similar in the implementation. The
failure mode here if one of these gets called is a compiler error, which
probably won't actually be easy to interpret. A runtime error could give more
information, and then you can also get a stack trace to see how the bad call is
reached.

[Florian Schneider, 2016/04/15 01:17:28]

I disagree. If we want to avoid the #ifdef here, one alternative could maybe be
to leave declarations in, but omit definitions, so that a use will result in a
linker error which would be fine as well.

[Vyacheslav Egorov (Google), 2016/04/18 15:56:41]

I am with Florian on this one. I think making them UNREACHABLE is worse because
it leaves dead code behind. I want to explicitly know which parts of pipeline
are used and which ones are not. 

+  // interpreted nature.
+#if !defined(TARGET_ARCH_DBC)
   void GenerateRuntimeCall(TokenPosition token_pos,
                            intptr_t deopt_id,
                            const RuntimeEntry& entry,
@@ -390,12 +399,6 @@ class FlowGraphCompiler : public ValueObject {
                               LocationSummary* locs,
                               const Function& target);
 
-  void GenerateAssertAssignable(TokenPosition token_pos,
-                                intptr_t deopt_id,
-                                const AbstractType& dst_type,
-                                const String& dst_name,
-                                LocationSummary* locs);
-
   void GenerateInstanceOf(TokenPosition token_pos,
                           intptr_t deopt_id,
                           const AbstractType& type,
@@ -426,12 +429,6 @@ class FlowGraphCompiler : public ValueObject {
   void GenerateListTypeCheck(Register kClassIdReg,
                              Label* is_instance_lbl);
 
-  void EmitComment(Instruction* instr);
-
-  bool NeedsEdgeCounter(TargetEntryInstr* block);
-
-  void EmitEdgeCounter(intptr_t edge_id);
-
   void EmitOptimizedInstanceCall(const StubEntry& stub_entry,
                                  const ICData& ic_data,
                                  intptr_t argument_count,
@@ -487,8 +484,16 @@ class FlowGraphCompiler : public ValueObject {
                                       bool needs_number_check,
                                       TokenPosition token_pos);
 
+  bool NeedsEdgeCounter(TargetEntryInstr* block);
+
+  void EmitEdgeCounter(intptr_t edge_id);
+#endif

[zra, 2016/04/14 18:27:48]

add  // !defined(TARGET_ARCH_DBC)

[Vyacheslav Egorov (Google), 2016/04/18 15:56:41]

Done.

+
   void EmitTrySync(Instruction* instr, intptr_t try_index);
 
+  void EmitComment(Instruction* instr);
+
+

[zra, 2016/04/14 18:27:48]

Extra space.

[Vyacheslav Egorov (Google), 2016/04/18 15:56:41]

Done.

   intptr_t StackSize() const;
 
   // Returns assembler label associated with the given block entry.
@@ -635,6 +640,9 @@ class FlowGraphCompiler : public ValueObject {
                                  LocationSummary* locs,
                                  const ICData& ic_data);
 
+  // DBC handles type tests differently from all other architectures due

[zra, 2016/04/14 18:27:48]

ditto.

[Vyacheslav Egorov (Google), 2016/04/18 15:56:41]

Acknowledged.

+  // to its interpreted nature.
+#if !defined(TARGET_ARCH_DBC)
   // Type checking helper methods.
   void CheckClassIds(Register class_id_reg,
                      const GrowableArray<intptr_t>& class_ids,
@@ -688,6 +696,7 @@ class FlowGraphCompiler : public ValueObject {
   void GenerateBoolToJump(Register bool_reg, Label* is_true, Label* is_false);
 
   void CopyParameters();
+#endif

[zra, 2016/04/14 18:27:48]

add  // !defined(TARGET_ARCH_DBC)

[Vyacheslav Egorov (Google), 2016/04/18 15:56:41]

Done.

 
   void GenerateInlinedGetter(intptr_t offset);
   void GenerateInlinedSetter(intptr_t offset);
@@ -720,7 +729,7 @@ class FlowGraphCompiler : public ValueObject {
     return stackmap_table_builder_;
   }
 
-#if defined(DEBUG)
+#if defined(DEBUG) && !defined(TARGET_ARCH_DBC)

[zra, 2016/04/14 18:27:48]

ditto or add comment.

[Vyacheslav Egorov (Google), 2016/04/18 15:56:41]

There is a comment in the CC code. Duplicated it here.

   void FrameStateUpdateWith(Instruction* instr);
   void FrameStatePush(Definition* defn);
   void FrameStatePop(intptr_t count);