[turbofan] Improve testability of the InstructionSelector.

src/compiler/instruction-selector.h

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_COMPILER_INSTRUCTION_SELECTOR_H_
 #define V8_COMPILER_INSTRUCTION_SELECTOR_H_
 
 #include <deque>
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/instruction.h"
 #include "src/compiler/machine-operator.h"
 #include "src/zone-containers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 // Forward declarations.
 struct CallBuffer;  // TODO(bmeurer): Remove this.
 class FlagsContinuation;
 
 class InstructionSelector V8_FINAL {
  public:
-  explicit InstructionSelector(InstructionSequence* sequence,
-                               SourcePositionTable* source_positions);
+  // Forward declarations.
+  class Features;
+
+  InstructionSelector(InstructionSequence* sequence,
+                      SourcePositionTable* source_positions,
+                      Features features = SupportedFeatures());
 
   // Visit code for the entire graph with the included schedule.
   void SelectInstructions();
 
   // ===========================================================================
   // ============= Architecture-independent code emission methods. =============
   // ===========================================================================
 
   Instruction* Emit(InstructionCode opcode, InstructionOperand* output,
                     size_t temp_count = 0, InstructionOperand* *temps = NULL);
@@ skipping 10 matching lines @@
   Instruction* Emit(InstructionCode opcode, InstructionOperand* output,
                     InstructionOperand* a, InstructionOperand* b,
                     InstructionOperand* c, InstructionOperand* d,
                     size_t temp_count = 0, InstructionOperand* *temps = NULL);
   Instruction* Emit(InstructionCode opcode, size_t output_count,
                     InstructionOperand** outputs, size_t input_count,
                     InstructionOperand** inputs, size_t temp_count = 0,
                     InstructionOperand* *temps = NULL);
   Instruction* Emit(Instruction* instr);
 
+  // ===========================================================================
+  // ============== Architecture-independent CPU feature methods. ==============
+  // ===========================================================================
+
+  class Features V8_FINAL {
+   public:
+    Features() : bits_(0) {}
+    explicit Features(unsigned bits) : bits_(bits) {}
+    explicit Features(CpuFeature f) : bits_(1u << f) {}
+    Features(CpuFeature f1, CpuFeature f2) : bits_((1u << f1) | (1u << f2)) {}
+
+    bool Contains(CpuFeature f) const { return (bits_ & (1u << f)); }
+
+   private:
+    unsigned bits_;
+  };
+
+  bool IsSupported(CpuFeature feature) const {
+    return features_.Contains(feature);
+  }
+
+  // Returns the features supported on the target platform.
+  static Features SupportedFeatures() {
+    return Features(CpuFeatures::SupportedFeatures());
+  }
+
  private:
   friend class OperandGenerator;
 
   // ===========================================================================
   // ============ Architecture-independent graph covering methods. =============
   // ===========================================================================
 
   // Checks if {block} will appear directly after {current_block_} when
   // assembling code, in which case, a fall-through can be used.
   bool IsNextInAssemblyOrder(const BasicBlock* block) const;
@@ skipping 94 matching lines @@
   Zone* zone() { return &zone_; }
 
   // ===========================================================================
 
   typedef zone_allocator<Instruction*> InstructionPtrZoneAllocator;
   typedef std::deque<Instruction*, InstructionPtrZoneAllocator> Instructions;
 
   Zone zone_;
   InstructionSequence* sequence_;
   SourcePositionTable* source_positions_;
+  Features features_;
   BasicBlock* current_block_;
   Instructions instructions_;
   BoolVector defined_;
   BoolVector used_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_SELECTOR_H_