Changeset 161172 in webkit

Timestamp:

Dec 30, 2013, 10:49:49 PM (12 years ago)

Author:

mark.lam@apple.com

Message:

CStack: Refactor to split the tracking of the jsStackLimit from the native stackLimit.
​https://bugs.webkit.org/show_bug.cgi?id=126331.

Not yet reviewed.

Previously, when using the C stack for the JS stack, VM::m_jsStackLimit is a union
with VM::m_stackLimit. We now separate them into 2 distinct fields but haven't yet
changed the computation of the limit values to set them with.

• interpreter/JSStack.cpp:

(JSC::JSStack::updateStackLimit):

• runtime/VM.h:
• runtime/VMEntryScope.cpp:

(JSC::VMEntryScope::VMEntryScope):
(JSC::VMEntryScope::~VMEntryScope):
(JSC::VMEntryScope::updateStackLimits):
(JSC::VMEntryScope::requiredCapacity):

• runtime/VMEntryScope.h:

Location:

branches/jsCStack/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• interpreter/JSStack.cpp (modified) (1 diff)
• runtime/VM.h (modified) (1 diff)
• runtime/VMEntryScope.cpp (modified) (4 diffs)
• runtime/VMEntryScope.h (modified) (2 diffs)

branches/jsCStack/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2013-12-30  Mark Lam  <mark.lam@apple.com>
+
+        CStack: Refactor to split the tracking of the jsStackLimit from the native stackLimit.
+        https://bugs.webkit.org/show_bug.cgi?id=126331.
+
+        Not yet reviewed.
+
+        Previously, when using the C stack for the JS stack, VM::m_jsStackLimit is a union
+        with VM::m_stackLimit. We now separate them into 2 distinct fields but haven't yet
+        changed the computation of the limit values to set them with.
+
+        * interpreter/JSStack.cpp:
+        (JSC::JSStack::updateStackLimit):
+        * runtime/VM.h:
+        * runtime/VMEntryScope.cpp:
+        (JSC::VMEntryScope::VMEntryScope):
+        (JSC::VMEntryScope::~VMEntryScope):
+        (JSC::VMEntryScope::updateStackLimits):
+        (JSC::VMEntryScope::requiredCapacity):
+        * runtime/VMEntryScope.h:
+
 2013-12-30  Mark Lam  <mark.lam@apple.com>
 

branches/jsCStack/Source/JavaScriptCore/interpreter/JSStack.cpp

@@ -206 +206 @@
 #endif
     if (m_vm.firstEntryScope)
-        m_vm.firstEntryScope->updateStackLimit();
+        m_vm.firstEntryScope->updateStackLimits();
 }
 

branches/jsCStack/Source/JavaScriptCore/runtime/VM.h

@@ -506 +506 @@
         const ClassInfo* m_initializingObjectClass;
 #endif
-
-#if ENABLE(LLINT_C_LOOP)
-        struct {
-            void* m_stackLimit;
-            void* m_jsStackLimit;
-        };
-#else
-        union {
-            void* m_stackLimit;
-            void* m_jsStackLimit;
-        };
-#endif
+        void* m_stackLimit;
+        void* m_jsStackLimit;
         void* m_lastStackTop;
         JSValue m_exception;

branches/jsCStack/Source/JavaScriptCore/runtime/VMEntryScope.cpp

@@ -38 +38 @@
     , m_prevFirstEntryScope(vm.firstEntryScope)
     , m_prevStackLimit(vm.stackLimit())
+#if !ENABLE(LLINT_C_LOOP)
+    , m_prevJSStackLimit(vm.jsStackLimit())
+#endif
     , m_prevLastStackTop(vm.lastStackTop())
 {
@@ -54 +57 @@
     vm.clearExceptionStack();
 
-    updateStackLimit();
+    updateStackLimits();
     vm.setLastStackTop(m_stack.origin());
 }
@@ -62 +65 @@
     m_vm.firstEntryScope = m_prevFirstEntryScope;
     m_vm.setStackLimit(m_prevStackLimit);
+#if !ENABLE(LLINT_C_LOOP)
+    m_vm.setJSStackLimit(m_prevJSStackLimit);
+#endif
     m_vm.setLastStackTop(m_prevLastStackTop);
 }
 
-void VMEntryScope::updateStackLimit()
+void VMEntryScope::updateStackLimits()
 {
-    void* limit = m_stack.recursionLimit(requiredCapacity());
-    m_vm.setStackLimit(limit);
+#if !ENABLE(LLINT_C_LOOP)
+    void* jsStackLimit = m_stack.recursionLimit(requiredCapacity(JSStackCapacity));
+    m_vm.setJSStackLimit(jsStackLimit);
+#endif
+    void* nativeStackLimit = m_stack.recursionLimit(requiredCapacity(NativeStackCapacity));
+    m_vm.setStackLimit(nativeStackLimit);
 }
 
-size_t VMEntryScope::requiredCapacity() const
+size_t VMEntryScope::requiredCapacity(CapacityType type) const
 {
-    Interpreter* interpreter = m_vm.interpreter;
+    UNUSED_PARAM(type);
 
     // We require a smaller stack budget for the error stack. This is to allow
@@ -85 +95 @@
     const size_t errorModeRequiredStack = 64 * KB;
 
+    Interpreter* interpreter = m_vm.interpreter;
     size_t requiredCapacity = interpreter->isInErrorHandlingMode() ? errorModeRequiredStack : requiredStack;
     RELEASE_ASSERT(m_stack.size() >= requiredCapacity);

branches/jsCStack/Source/JavaScriptCore/runtime/VMEntryScope.h

@@ -41 +41 @@
     JS_EXPORT_PRIVATE ~VMEntryScope();
 
-    void updateStackLimit();
+    void updateStackLimits();
     JSGlobalObject* globalObject() const { return m_globalObject; }
 
 private:
-    size_t requiredCapacity() const;
+    enum CapacityType {
+        JSStackCapacity,
+        NativeStackCapacity,
+    };
+    size_t requiredCapacity(CapacityType) const;
 
     VM& m_vm;
@@ -52 +56 @@
     JSGlobalObject* m_globalObject;
 
-    // m_prevFirstEntryScope, m_prevStackLimit & m_prevLastStackTop may belong to a different thread's stack.
+    // The following pointers may point to a different thread's stack.
     VMEntryScope* m_prevFirstEntryScope;
     void* m_prevStackLimit;
+#if !ENABLE(LLINT_C_LOOP)
+    void* m_prevJSStackLimit;
+#endif
     void* m_prevLastStackTop;
 };