Revert "Revert "Introduce Goto instructions to the flow graph.""

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 100 matching lines @@
         ASSERT(instr->locs() != NULL);
         EmitInstructionPrologue(instr);
         pending_deoptimization_env_ = instr->env();
         instr->EmitNativeCode(this);
       }
     }
     if (instr->next() != NULL) {
       BlockEntryInstr* successor = instr->next()->AsBlockEntry();
       ASSERT(successor != NULL);
       frame_register_allocator()->Spill();
-      // The block ended with a "goto".  We can fall through if it is the
-      // next block in the list.  Otherwise, we need a jump.
-      if ((i == block_order().length() - 1) ||
-          (block_order()[i + 1] != successor)) {
+      if (!IsNextBlock(successor)) {
         assembler()->jmp(GetBlockLabel(successor));
       }
     }
   }
 }
 
 
 void FlowGraphCompiler::Bailout(const char* reason) {
   const char* kFormat = "FlowGraphCompiler Bailout: %s %s.";
   const char* function_name = parsed_function().function().ToCString();
@@ skipping 13 matching lines @@
 }
 
 
 Label* FlowGraphCompiler::GetBlockLabel(
     BlockEntryInstr* block_entry) const {
   intptr_t block_index = block_entry->postorder_number();
   return &block_info_[block_index]->label;
 }
 
 
-bool FlowGraphCompiler::IsNextBlock(TargetEntryInstr* block_entry) const {
+bool FlowGraphCompiler::IsNextBlock(BlockEntryInstr* block_entry) const {
   intptr_t current_index = reverse_index(current_block()->postorder_number());
-  return block_order_[current_index + 1] == block_entry;
+  return (current_index < (block_order().length() - 1)) &&
+      (block_order()[current_index + 1] == block_entry);
 }
 
 
 void FlowGraphCompiler::GenerateDeferredCode() {
   for (intptr_t i = 0; i < deopt_stubs_.length(); i++) {
     deopt_stubs_[i]->GenerateCode(this);
   }
 }
 
 
@@ skipping 427 matching lines @@
         reg = AllocateFreeRegister(blocked_registers);
       }
       locs->set_in(i, Location::RegisterLocation(reg));
     }
 
     Pop(reg, instr->InputAt(i));
   }
 
   // If this instruction is call spill everything that was not consumed by
   // input locations.
-  if (locs->is_call() || instr->IsBranch()) {
+  if (locs->is_call() || instr->IsBranch() || instr->IsGoto()) {
     Spill();
   }
 
   // Allocate all unallocated temp locations.
   for (intptr_t i = 0; i < locs->temp_count(); i++) {
     Location loc = locs->temp(i);
     if (loc.IsUnallocated()) {
       ASSERT(loc.policy() == Location::kRequiresRegister);
       loc = Location::RegisterLocation(
         AllocateFreeRegister(blocked_registers));
@@ skipping 174 matching lines @@
       return;
     }
   }
 
   // This move is not blocked.
   EmitMove(index);
 }
 
 
 }  // namespace dart