[Oilpan] Set stack limit using estimated sizes

Source/platform/heap/StackFrameDepth.cpp

 // 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"
 
 #include "public/platform/Platform.h"
 
 #if OS(WIN)
 #include <stddef.h>
 #include <windows.h>
 #include <winnt.h>
 #elif defined(__GLIBC__)
 extern "C" void* __libc_stack_end;  // NOLINT
 #endif
 
 namespace blink {
 
+const int StackFrameDepth::kStackRoomSize = 1024;

[haraken, 2015/02/10 12:15:09]

Shall we make this a static variable of StackFrameDepth::configureLimit()?

[kouhei (in TOK), 2015/02/10 12:35:38]

static const int +1

[peria, 2015/02/12 02:31:58]

Done.

 static const char* s_avoidOptimization = nullptr;
 
 // NEVER_INLINE ensures that |dummy| array on configureLimit() is not optimized away,
 // and the stack frame base register is adjusted |kSafeStackFrameSize|.
 NEVER_INLINE static uintptr_t currentStackFrameBaseOnCallee(const char* dummy)
 {
     s_avoidOptimization = dummy;
     return StackFrameDepth::currentStackFrame();
 }
 
 void StackFrameDepth::configureLimit()
 {
-    // Allocate a large object in stack and query stack frame pointer after it.
+    size_t stackSize = getUnderestimatedStackSize();
+    if (stackSize) {
+        size_t stackBase = reinterpret_cast<size_t>(getStackStart());
+        m_stackFrameLimit = stackBase - stackSize + kStackRoomSize;
+        return;
+    }
+
+    // Fallback version
+    // Allocate a 32KB object on stack and query stack frame base after it.
     char dummy[kSafeStackFrameSize];
     m_stackFrameLimit = currentStackFrameBaseOnCallee(dummy);
 
     // Assert that the stack frame can be used.
-    dummy[sizeof(dummy) - 1] = 0;
+    dummy[0] = 0;

[haraken, 2015/02/10 12:15:09]

What is this change for?

[kouhei (in TOK), 2015/02/10 12:35:38]

To check if the top of the stack is actually writable, [0] was correct, as
[sizeof(dummy) -1] is actually at bottom of the stack when stack grow toward
lower address.
Please add it to CL description and/or separate CL.

[peria, 2015/02/12 02:31:58]

will do in another CL.

 }
 
 size_t StackFrameDepth::getUnderestimatedStackSize()
 {
 #if defined(__GLIBC__) || OS(ANDROID) || OS(FREEBSD)
-    // We cannot get the stack size in these platforms because
-    // pthread_getattr_np() can fail for the main thread.
-    // This is OK because ThreadState::current() doesn't use the stack size
-    // in these platforms.
+    // We cannot get the stack size on the main thread in these platforms, because

[haraken, 2015/02/10 12:15:09]

Update the comment like:

// pthread_getattr_np() can fail if the thread is not invoked by
pthread_create() (e.g., the main thread of webkit_unit_tests). In this case,
this method returns 0 and the caller must handle it.

[peria, 2015/02/12 02:31:58]

Done.

+    // pthread_getattr_np() can fail.
+    // In this case, this method returns 0 and the caller must handle it.
+
+    pthread_attr_t attr;
+    int error;
+#if OS(FREEBSD)
+    pthread_attr_init(&attr);
+    error = pthread_attr_get_np(pthread_self(), &attr);
+#else
+    error = pthread_getattr_np(pthread_self(), &attr);
+#endif
+    if (!error) {
+        void* base;
+        size_t size;
+        error = pthread_attr_getstack(&attr, &base, &size);
+        RELEASE_ASSERT(!error);
+        pthread_attr_destroy(&attr);
+        return size;
+    }
+#if OS(FREEBSD)
+    pthread_attr_destroy(&attr);
+#endif
+
     return 0;
 #elif OS(MACOSX)
     return pthread_get_stacksize_np(pthread_self());
 #elif OS(WIN) && COMPILER(MSVC)
     // On Windows stack limits for the current thread are available in
     // the thread information block (TIB). Its fields can be accessed through
     // FS segment register on x86 and GS segment register on x86_64.
 #ifdef _WIN64
     return __readgsqword(offsetof(NT_TIB64, StackBase)) - __readgsqword(offsetof(NT_TIB64, StackLimit));
 #else
     return __readfsdword(offsetof(NT_TIB, StackBase)) - __readfsdword(offsetof(NT_TIB, StackLimit));
 #endif
 #else
+#error "Stack frame size estimation not supported on this platform."
     return 0;
 #endif
 }
 
 void* StackFrameDepth::getStackStart()
 {
 #if defined(__GLIBC__) || OS(ANDROID) || OS(FREEBSD)
     pthread_attr_t attr;
     int error;
 #if OS(FREEBSD)
@@ skipping 33 matching lines @@
     return reinterpret_cast<void*>(__readgsqword(offsetof(NT_TIB64, StackBase)));
 #else
     return reinterpret_cast<void*>(__readfsdword(offsetof(NT_TIB, StackBase)));
 #endif
 #else
 #error Unsupported getStackStart on this platform.
 #endif
 }
 
 } // namespace blink