Make VM state tracking to be independent of logging and profiling.

src/vm-state-inl.h

Index: src/vm-state-inl.h
diff --git a/src/vm-state-inl.h b/src/vm-state-inl.h
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+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_VM_STATE_INL_H_
+#define V8_VM_STATE_INL_H_
+
+#include "vm-state.h"
+
+namespace v8 {
+namespace internal {
+
+//
+// VMState class implementation.  A simple stack of VM states held by the
+// logger and partially threaded through the call stack.  States are pushed by
+// VMState construction and popped by destruction.
+//
+#ifdef ENABLE_VMSTATE_TRACKING
+inline const char* StateToString(StateTag state) {
+  switch (state) {
+    case JS:
+      return "JS";
+    case GC:
+      return "GC";
+    case COMPILER:
+      return "COMPILER";
+    case OTHER:
+      return "OTHER";
+    default:
+      UNREACHABLE();
+      return NULL;
+  }
+}
+
+VMState::VMState(StateTag state)
+    : disabled_(true),
+      state_(OTHER),
+      external_callback_(NULL) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (!Logger::is_logging() && !CpuProfiler::is_profiling()) {
+    return;
+  }
+#endif
+
+  disabled_ = false;
+#if !defined(ENABLE_HEAP_PROTECTION)
+  // When not protecting the heap, there is no difference between
+  // EXTERNAL and OTHER.  As an optimization in that case, we will not
+  // perform EXTERNAL->OTHER transitions through the API.  We thus
+  // compress the two states into one.
+  if (state == EXTERNAL) state = OTHER;
+#endif
+  state_ = state;
+  previous_ = current_state_;  // Save the previous state.
+  current_state_ = this;       // Install the new state.
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (FLAG_log_state_changes) {
+    LOG(UncheckedStringEvent("Entering", StateToString(state_)));
+    if (previous_ != NULL) {
+      LOG(UncheckedStringEvent("From", StateToString(previous_->state_)));
+    }
+  }
+#endif
+
+#ifdef ENABLE_HEAP_PROTECTION
+  if (FLAG_protect_heap) {
+    if (state_ == EXTERNAL) {
+      // We are leaving V8.
+      ASSERT((previous_ != NULL) && (previous_->state_ != EXTERNAL));
+      Heap::Protect();
+    } else if ((previous_ == NULL) || (previous_->state_ == EXTERNAL)) {
+      // We are entering V8.
+      Heap::Unprotect();
+    }
+  }
+#endif
+}
+
+
+VMState::~VMState() {
+  if (disabled_) return;
+  current_state_ = previous_;  // Return to the previous state.
+
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (FLAG_log_state_changes) {
+    LOG(UncheckedStringEvent("Leaving", StateToString(state_)));
+    if (previous_ != NULL) {
+      LOG(UncheckedStringEvent("To", StateToString(previous_->state_)));
+    }
+  }
+#endif  // ENABLE_LOGGING_AND_PROFILING
+
+#ifdef ENABLE_HEAP_PROTECTION
+  if (FLAG_protect_heap) {
+    if (state_ == EXTERNAL) {
+      // We are reentering V8.
+      ASSERT((previous_ != NULL) && (previous_->state_ != EXTERNAL));
+      Heap::Unprotect();
+    } else if ((previous_ == NULL) || (previous_->state_ == EXTERNAL)) {
+      // We are leaving V8.
+      Heap::Protect();
+    }
+  }
+#endif  // ENABLE_HEAP_PROTECTION
+}
+#endif  // ENABLE_VMSTATE_TRACKING
+
+} }  // namespace v8::internal
+
+#endif  // V8_VM_STATE_INL_H_