Oilpan: Query stack frame register instead of manual bookkeeping

Source/platform/heap/StackFrameDepth.cpp

Index: Source/platform/heap/StackFrameDepth.cpp
diff --git a/Source/platform/heap/StackFrameDepth.cpp b/Source/platform/heap/StackFrameDepth.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..3389f7b6514b2ad9811e5e7ecde15445571c8277
--- /dev/null
+++ b/Source/platform/heap/StackFrameDepth.cpp
@@ -0,0 +1,28 @@
+// 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.
+
+#include "config.h"
+#include "platform/heap/StackFrameDepth.h"
+
+namespace blink {
+
+static const char* s_avoidOptimization = nullptr;
+NEVER_INLINE static uintptr_t estimateStackFrameBaseOnCallee(const char* dummy)
+{
+    s_avoidOptimization = dummy;
+    return StackFrameDepth::estimateCurrentStackFrame();
+}
+
+void StackFrameDepth::configureLimit()

[haraken, 2015/01/08 01:14:22]

Can we add NEVER_INLINE to configureLimit and remove
estimateStackFrameBaseOnCallee?

[kouhei (in TOK), 2015/01/08 03:29:54]

No. We want %rbp after dummy[] is pushed.

+{
+    // Allocate a large object in stack and query stack frame pointer after it.
+    const size_t kTypicalPointersPerFrame = 4; // Return address + 3 local variable/argument
+    char dummy[kMaxDepth * kTypicalPointersPerFrame * sizeof(void*)];
+    m_safeStackFrame = estimateStackFrameBaseOnCallee(dummy);
+
+    // Assert that the stack frame can be used.
+    dummy[sizeof(dummy)-1] = 0;

[haraken, 2015/01/08 01:14:22]

Add spaces around '-'.

[haraken, 2015/01/08 01:14:22]

I guess if we move this code up to line 22, s_avoidOptimization won't be needed.

[kouhei (in TOK), 2015/01/08 03:29:54]

Done.

+}
+
+} // namespace blink