Changeset 150600 in webkit

Timestamp:

May 23, 2013 11:51:00 AM (11 years ago)

Author:

Patrick Gansterer

Message:

[WIN] Implement correct detection of stack size
​https://bugs.webkit.org/show_bug.cgi?id=116661

Reviewed by Oliver Hunt.

• wtf/StackBounds.cpp:

(WTF):
(WTF::StackBounds::initialize):

Location:

trunk/Source/WTF

Files:

• ChangeLog (modified) (1 diff)
• wtf/StackBounds.cpp (modified) (2 diffs)

trunk/Source/WTF/ChangeLog

@@ +1 @@
+2013-05-23  Patrick Gansterer  <paroga@webkit.org>
+
+        [WIN] Implement correct detection of stack size
+        https://bugs.webkit.org/show_bug.cgi?id=116661
+
+        Reviewed by Oliver Hunt.
+
+        * wtf/StackBounds.cpp:
+        (WTF):
+        (WTF::StackBounds::initialize):
+
 2013-05-22  Dean Jackson  <dino@apple.com>
 

trunk/Source/WTF/wtf/StackBounds.cpp

@@ -59 +59 @@
 //
 // These platforms should now be working correctly:
-//     DARWIN, QNX, UNIX
+//     DARWIN, QNX, UNIX, WINDOWS
 // These platforms are not:
-//     WINDOWS, SOLARIS, OPENBSD, WINCE
+//     SOLARIS, OPENBSD
 //
 // FIXME: remove this! - this code unsafely guesses at stack sizes!
-#if OS(WINDOWS) || OS(SOLARIS) || OS(OPENBSD)
+#if OS(SOLARIS) || OS(OPENBSD)
 // Based on the current limit used by the JSC parser, guess the stack size.
 static const ptrdiff_t estimatedStackSize = 128 * sizeof(void*) * 1024;
@@ -164 +164 @@
 }
 
-#elif OS(WINCE)
-
-static bool detectGrowingDownward(void* previousFrame)
-{
-    // Find the address of this stack frame by taking the address of a local variable.
-    int thisFrame;
-    return previousFrame > &thisFrame;
-}
-
-static inline bool isPageWritable(void* page)
-{
-    MEMORY_BASIC_INFORMATION memoryInformation;
-    DWORD result = VirtualQuery(page, &memoryInformation, sizeof(memoryInformation));
-
-    // return false on error, including ptr outside memory
-    if (result != sizeof(memoryInformation))
-        return false;
-
-    DWORD protect = memoryInformation.Protect & ~(PAGE_GUARD | PAGE_NOCACHE);
-    return protect == PAGE_READWRITE
-        || protect == PAGE_WRITECOPY
-        || protect == PAGE_EXECUTE_READWRITE
-        || protect == PAGE_EXECUTE_WRITECOPY;
-}
-
-static inline void* getLowerStackBound(char* currentPage, DWORD pageSize)
-{
-    while (currentPage > 0) {
-        // check for underflow
-        if (currentPage >= reinterpret_cast<char*>(pageSize))
-            currentPage -= pageSize;
-        else
-            currentPage = 0;
-
-        if (!isPageWritable(currentPage))
-            return currentPage + pageSize;
-    }
-
-    return 0;
-}
-
-static inline void* getUpperStackBound(char* currentPage, DWORD pageSize)
-{
-    do {
-        // guaranteed to complete because isPageWritable returns false at end of memory
-        currentPage += pageSize;
-    } while (isPageWritable(currentPage));
-
-    return currentPage - pageSize;
-}
-
-void StackBounds::initialize()
-{
-    // find the address of this stack frame by taking the address of a local variable
-    void* thisFrame = &thisFrame;
-    bool isGrowingDownward = detectGrowingDownward(thisFrame);
-
+#elif OS(WINDOWS)
+
+void StackBounds::initialize()
+{
     SYSTEM_INFO systemInfo;
     GetSystemInfo(&systemInfo);
     DWORD pageSize = systemInfo.dwPageSize;
 
-    // scan all of memory starting from this frame, and return the last writeable page found
-    char* currentPage = reinterpret_cast<char*>(reinterpret_cast<DWORD>(thisFrame) & ~(pageSize - 1));
-    void* lowerStackBound = getLowerStackBound(currentPage, pageSize);
-    void* upperStackBound = getUpperStackBound(currentPage, pageSize);
-
-    m_origin = isGrowingDownward ? upperStackBound : lowerStackBound;
-    m_bound = isGrowingDownward ? lowerStackBound : upperStackBound;
-}
-
-#elif OS(WINDOWS)
-
-void StackBounds::initialize()
-{
-#if CPU(X86) && COMPILER(MSVC)
-    // offset 0x18 from the FS segment register gives a pointer to
-    // the thread information block for the current thread
-    NT_TIB* pTib;
-    __asm {
-        MOV EAX, FS:[18h]
-        MOV pTib, EAX
-    }
-    m_origin = static_cast<void*>(pTib->StackBase);
-#elif CPU(X86) && COMPILER(GCC)
-    // offset 0x18 from the FS segment register gives a pointer to
-    // the thread information block for the current thread
-    NT_TIB* pTib;
-    asm ( "movl %%fs:0x18, %0\n"
-          : "=r" (pTib)
-        );
-    m_origin = static_cast<void*>(pTib->StackBase);
-#elif CPU(X86_64)
-    PNT_TIB64 pTib = reinterpret_cast<PNT_TIB64>(NtCurrentTeb());
-    m_origin = reinterpret_cast<void*>(pTib->StackBase);
+    MEMORY_BASIC_INFORMATION stackOrigin;
+    VirtualQuery(&stackOrigin, &stackOrigin, sizeof(stackOrigin));
+    // stackOrigin.AllocationBase points to the reserved stack memory base address.
+
+    m_origin = static_cast<char*>(stackOrigin.BaseAddress) + stackOrigin.RegionSize;
+#if OS(WINCE)
+    MEMORY_BASIC_INFORMATION stackMemory;
+    VirtualQuery(m_origin, &stackMemory, sizeof(stackMemory));
+
+    m_bound = static_cast<char*>(m_origin) - stackMemory.RegionSize + pageSize;
 #else
-#error Need a way to get the stack bounds on this platform (Windows)
-#endif
-    // Looks like we should be able to get pTib->StackLimit
-    m_bound = estimateStackBound(m_origin);
+    // The stack on Windows consists out of three parts (reserved memory, a guard page and initially committed memory),
+    // which need to me queried seperately to get the full size of the stack.
+    // See http://msdn.microsoft.com/en-us/library/ms686774%28VS.85%29.aspx for more information.
+
+    MEMORY_BASIC_INFORMATION reservedMemory;
+    VirtualQuery(stackOrigin.AllocationBase, &reservedMemory, sizeof(reservedMemory));
+    ASSERT(reservedMemory.State == MEM_RESERVE);
+    // reservedMemory.BaseAddress and reservedMemory.RegionSize describe reserved (uncommitted) portion of the stack.
+
+    MEMORY_BASIC_INFORMATION guardPage;
+    VirtualQuery(static_cast<char*>(reservedMemory.BaseAddress) + reservedMemory.RegionSize, &guardPage, sizeof(guardPage));
+    ASSERT(guardPage.Protect & PAGE_GUARD);
+    // guardPage.BaseAddress and guardPage.RegionSize describe the guard page.
+
+    MEMORY_BASIC_INFORMATION committedMemory;
+    VirtualQuery(static_cast<char*>(guardPage.BaseAddress) + guardPage.RegionSize, &committedMemory, sizeof(committedMemory));
+    ASSERT(committedMemory.State == MEM_COMMIT);
+    // committedMemory.BaseAddress, committedMemory.RegionSize describe the committed (i.e. accessed) portion of the stack.
+
+    m_bound = static_cast<char*>(m_origin) - (reservedMemory.RegionSize - guardPage.RegionSize + committedMemory.RegionSize) + pageSize;
+#endif
 }