Indirectly dispatch all backtracking jumps through the same block.

runtime/vm/intermediate_language.h

Index: runtime/vm/intermediate_language.h
diff --git a/runtime/vm/intermediate_language.h b/runtime/vm/intermediate_language.h
index 0f0cfdb8d13eaff760112adcd63f7464f7e50684..4430060c11bf0f669d143e6a338b8e52d5da1d75 100644
--- a/runtime/vm/intermediate_language.h
+++ b/runtime/vm/intermediate_language.h
@@ -2191,6 +2191,7 @@ class GotoInstr : public TemplateInstruction<0, NoThrow> {
 // In order to preserve split-edge form, an indirect goto does not itself point
 // to its targets. Instead, for each possible target, the successors_ field
 // will contain an ordinary goto instruction that jumps to the target.
+// TODO(zerny): Implement direct support instead of embedding gotos.
 //
 // Byte offsets of all possible targets are stored in the offsets_ array. The
 // desired offset is looked up while the generated code is executing, and passed
@@ -2227,17 +2228,7 @@ class IndirectGotoInstr : public TemplateInstruction<1, NoThrow> {
   virtual void PrintTo(BufferFormatter* f) const;
 
   const GrowableObjectArray& offsets() const { return offsets_; }
-  void SetOffsetCount(Isolate* isolate, intptr_t count) {
-    if (offsets_.Capacity() < count) {
-      offsets_.Grow(count, Heap::kOld);
-    }
-    if (offsets_.Length() < count) {
-      offsets_.SetLength(count);
-    }
-  }
-  void SetOffsetAt(Isolate* isolate, intptr_t index, intptr_t offset) {
-    offsets_.SetAt(index, Smi::ZoneHandle(isolate, Smi::New(offset)));
-  }
+  void ComputeOffsetTable(Isolate* isolate);
 
  private:
   GrowableArray<TargetEntryInstr*> successors_;