src/jump-target.h

// Copyright 2008 the V8 project authors. All rights reserved.
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#ifndef V8_JUMP_TARGET_H_
#define V8_JUMP_TARGET_H_

#if V8_TARGET_ARCH_IA32
#include "jump-target-heavy.h"
#elif V8_TARGET_ARCH_X64
#include "jump-target-heavy.h"
#elif V8_TARGET_ARCH_ARM
#include "jump-target-light.h"
#elif V8_TARGET_ARCH_MIPS
#include "jump-target-light.h"
#else
#error Unsupported target architecture.
#endif

namespace v8 {
namespace internal {

// -------------------------------------------------------------------------
// Shadow break targets
//
// A shadow break target represents a break target that is temporarily
// shadowed by another one (represented by the original during
// shadowing).  They are used to catch jumps to labels in certain
// contexts, e.g. try blocks.  After shadowing ends, the formerly
// shadowed target is again represented by the original and the
// ShadowTarget can be used as a jump target in its own right,
// representing the formerly shadowing target.

class ShadowTarget : public BreakTarget {
 public:
  // Construct a shadow jump target.  After construction the shadow
  // target object holds the state of the original target, and the
  // original target is actually a fresh one that intercepts control
  // flow intended for the shadowed one.
  explicit ShadowTarget(BreakTarget* shadowed);

  virtual ~ShadowTarget() {}

  // End shadowing.  After shadowing ends, the original jump target
  // again gives access to the formerly shadowed target and the shadow
  // target object gives access to the formerly shadowing target.
  void StopShadowing();

  // During shadowing, the currently shadowing target.  After
  // shadowing, the target that was shadowed.
  BreakTarget* other_target() const { return other_target_; }

 private:
  // During shadowing, the currently shadowing target.  After
  // shadowing, the target that was shadowed.
  BreakTarget* other_target_;

#ifdef DEBUG
  bool is_shadowing_;
#endif

  DISALLOW_COPY_AND_ASSIGN(ShadowTarget);
};

} }  // namespace v8::internal

#endif  // V8_JUMP_TARGET_H_