[turbofan] Don't spread global flag checks all over the compiler code.

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 <map>
 
 #include "src/compiler/common-operator.h"
@@ skipping 15 matching lines @@
 
 typedef ZoneVector<InstructionOperand> InstructionOperandVector;
 
 
 // Instruction selection generates an InstructionSequence for a given Schedule.
 class InstructionSelector final {
  public:
   // Forward declarations.
   class Features;
 
-  InstructionSelector(Zone* zone, size_t node_count, Linkage* linkage,
-                      InstructionSequence* sequence, Schedule* schedule,
-                      SourcePositionTable* source_positions,
-                      Features features = SupportedFeatures());
+  enum SourcePositionMode { kCallSourcePositions, kAllSourcePositions };
+
+  InstructionSelector(
+      Zone* zone, size_t node_count, Linkage* linkage,
+      InstructionSequence* sequence, Schedule* schedule,
+      SourcePositionTable* source_positions,
+      SourcePositionMode source_position_mode = kCallSourcePositions,
+      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 162 matching lines @@
   InstructionSequence* sequence() const { return sequence_; }
   Zone* instruction_zone() const { return sequence()->zone(); }
   Zone* zone() const { return zone_; }
 
   // ===========================================================================
 
   Zone* const zone_;
   Linkage* const linkage_;
   InstructionSequence* const sequence_;
   SourcePositionTable* const source_positions_;
+  SourcePositionMode const source_position_mode_;
   Features features_;
   Schedule* const schedule_;
   BasicBlock* current_block_;
   ZoneVector<Instruction*> instructions_;
   BoolVector defined_;
   BoolVector used_;
   IntVector virtual_registers_;
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_SELECTOR_H_