src/hotspot/share/runtime/stackWatermark.inline.hpp

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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#ifndef SHARE_RUNTIME_STACKWATERMARK_INLINE_HPP
#define SHARE_RUNTIME_STACKWATERMARK_INLINE_HPP

#include "runtime/stackWatermark.hpp"

#include "code/nmethod.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/registerMap.hpp"

static inline bool is_above_watermark(uintptr_t sp, uintptr_t watermark) {
  if (watermark == 0) {
    return false;
  }
  return sp > watermark;
}

// Returns true for frames where stack watermark barriers have been inserted.
// This function may return false negatives, but may never return true if a
// frame has no barrier.
inline bool StackWatermark::has_barrier(const frame& f) {
  if (f.is_interpreted_frame()) {
    return true;
  }
  if (f.is_compiled_frame()) {
    nmethod* nm = f.cb()->as_nmethod();
    if (nm->is_compiled_by_c1() || nm->is_compiled_by_c2()) {
      return true;
    }
    if (nm->is_native_method()) {
      return true;
    }
  }
  return false;
}

inline bool StackWatermark::processing_started(uint32_t state) const {
  return StackWatermarkState::epoch(state) == epoch_id();
}

inline bool StackWatermark::processing_completed(uint32_t state) const {
  assert(processing_started(state), "Check is only valid if processing has been started");
  return StackWatermarkState::is_done(state);
}

inline void StackWatermark::ensure_safe(const frame& f) {
  assert(processing_started(), "Processing should already have started");

  if (processing_completed_acquire()) {
    return;
  }

  uintptr_t f_fp = reinterpret_cast<uintptr_t>(f.real_fp());

  if (is_above_watermark(f_fp, watermark())) {
    process_one();
  }

  assert_is_frame_safe(f);
}

inline void StackWatermark::before_unwind() {
  frame f = _jt->last_frame();

  // Skip any stub frames etc up until the frame that triggered before_unwind().
  RegisterMap map(_jt,
                  RegisterMap::UpdateMap::skip,
                  RegisterMap::ProcessFrames::skip,
                  RegisterMap::WalkContinuation::skip);
  if (f.is_safepoint_blob_frame() || f.is_runtime_frame()) {
    f = f.sender(&map);
  }

  assert_is_frame_safe(f);
  assert(!f.is_runtime_frame(), "should have skipped all runtime stubs");

  // before_unwind() potentially exposes a new frame. The new exposed frame is
  // always the caller of the top frame.
  if (!f.is_first_frame()) {
    f = f.sender(&map);
    ensure_safe(f);
  }
}

inline void StackWatermark::after_unwind() {
  frame f = _jt->last_frame();

  if (f.is_safepoint_blob_frame() || f.is_runtime_frame()) {
    // Skip safepoint blob.
    RegisterMap map(_jt,
                    RegisterMap::UpdateMap::skip,
                    RegisterMap::ProcessFrames::skip,
                    RegisterMap::WalkContinuation::skip);
    f = f.sender(&map);
  }

  assert(!f.is_runtime_frame(), "should have skipped all runtime stubs");

  // after_unwind() potentially exposes the top frame.
  ensure_safe(f);
}

inline void StackWatermark::on_iteration(const frame& f) {
  if (process_on_iteration()) {
    ensure_safe(f);
  }
}

#endif // SHARE_RUNTIME_STACKWATERMARK_INLINE_HPP