Oilpan: Query stack frame register instead of manual bookkeeping

Source/platform/heap/StackFrameDepth.h

+// Copyright 2015 The Chromium 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 StackFrameDepth_h
+#define StackFrameDepth_h
+
+#include "platform/PlatformExport.h"
+#include "wtf/Assertions.h"
+#include <stdint.h>
+
+namespace blink {
+
+// StackFrameDepth keeps track of current call stack frame depth.
+// Use isSafeToRecurse() to query if there is a room in current
+// call stack for more recursive call.
+class PLATFORM_EXPORT StackFrameDepth final {
+public:
+    inline bool isSafeToRecurse()
+    {
+        ASSERT(m_stackFrameLimit);
+
+        // Below comparison assumes callstack to glow downward,
+        // which is true for all ABI Blink currently supports.
+        return currentStackFrame() > m_stackFrameLimit;
+    }
+
+    static uintptr_t currentStackFrame(const char* dummy = nullptr)
+    {
+#if COMPILER(GCC)
+        return reinterpret_cast<uintptr_t>(__builtin_frame_address(0));
+#elif COMPILER(MSVC)
+        return reinterpret_cast<uintptr_t>(&dummy) - sizeof(void*);
+#else
+#error "Stack frame pointer estimation not supported on this platform."
+        return 0;
+#endif
+    }
+
+    void configureLimit();
+
+private:
+    // The maximum depth of eager, unrolled trace() calls that is
+    // considered safe and allowed.
+    static const int kSafeStackFrameSize = 32 * 1024;
+
+    uintptr_t m_stackFrameLimit;
+};
+
+} // namespace blink
+
+#endif // StackFrameDepth_h