[Oilpan] Set stack limit using estimated sizes

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
index 2d7985a1d3bf9fd1d72f07cb50a8673e3ff6c5eb..9b0250672e57e430d17e90063542d69bcf56df8d 100644
--- a/Source/platform/heap/StackFrameDepth.cpp
+++ b/Source/platform/heap/StackFrameDepth.cpp
@@ -17,6 +17,7 @@ extern "C" void* __libc_stack_end;  // NOLINT
 
 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,
@@ -29,21 +30,49 @@ NEVER_INLINE static uintptr_t currentStackFrameBaseOnCallee(const char* dummy)
 
 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());
@@ -57,6 +86,7 @@ size_t StackFrameDepth::getUnderestimatedStackSize()
     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
 }