Streamline code generator for branches and comparisons.

runtime/vm/flow_graph_compiler.h

 // 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.
 
 #ifndef VM_FLOW_GRAPH_COMPILER_H_
 #define VM_FLOW_GRAPH_COMPILER_H_
 
 #include "vm/allocation.h"
 #include "vm/assembler.h"
 #include "vm/code_descriptors.h"
 #include "vm/code_generator.h"
 #include "vm/intermediate_language.h"
 
 namespace dart {
 
 // Forward declarations.
 class Code;
 class DeoptInfoBuilder;
 class FlowGraph;
 class FlowGraphCompiler;
 class Function;
 template <typename T> class GrowableArray;
 class ParsedFunction;
 
 
+struct BranchLabels {
+  Label* true_label;
+  Label* false_label;
+  Label* fall_through;
+};
+
+
 class ParallelMoveResolver : public ValueObject {
  public:
   explicit ParallelMoveResolver(FlowGraphCompiler* compiler);
 
   // Resolve a set of parallel moves, emitting assembler instructions.
   void EmitNativeCode(ParallelMoveInstr* parallel_move);
 
  private:
   class ScratchFpuRegisterScope : public ValueObject {
    public:
@@ skipping 345 matching lines @@
                                  intptr_t token_pos);
 
   void EmitTrySync(Instruction* instr, intptr_t try_index);
 
   intptr_t StackSize() const;
 
   // Returns assembler label associated with the given block entry.
   Label* GetJumpLabel(BlockEntryInstr* block_entry) const;
   bool WasCompacted(BlockEntryInstr* block_entry) const;
 
+  // Returns the label of the fall-through of the current block.
+  Label* NextNonEmptyLabel() const;
+
   // Returns true if there is a next block after the current one in
   // the block order and if it is the given block.
   bool CanFallThroughTo(BlockEntryInstr* block_entry) const;
 
+  // Return true-, false- and fall-through label for a branch instruction.
+  BranchLabels CreateBranchLabels(BranchInstr* branch) const;
+
   void AddExceptionHandler(intptr_t try_index,
                            intptr_t outer_try_index,
                            intptr_t pc_offset,
                            const Array& handler_types,
                            bool needs_stacktrace);
   void SetNeedsStacktrace(intptr_t try_index);
   void AddCurrentDescriptor(PcDescriptors::Kind kind,
                             intptr_t deopt_id,
                             intptr_t token_pos);
 
@@ skipping 194 matching lines @@
   // that should be used when deoptimizing we store it in this variable.
   // In future AddDeoptStub should be moved out of the instruction template.
   Environment* pending_deoptimization_env_;
 
   DISALLOW_COPY_AND_ASSIGN(FlowGraphCompiler);
 };
 
 }  // namespace dart
 
 #endif  // VM_FLOW_GRAPH_COMPILER_H_