Changeset 258824 in webkit

Timestamp:

Mar 22, 2020 5:40:46 PM (4 years ago)

Author:

ysuzuki@apple.com

Message:

[JSC] Add JSC::keepAlive(JSValue)
​https://bugs.webkit.org/show_bug.cgi?id=209398

Reviewed by Mark Lam.

Add JSC::keepAlive(JSValue). This is useful to make some JSValue variable alive from GC.

• heap/HeapCell.cpp:
• runtime/JSCJSValue.cpp:

(JSC::keepAlive):

• runtime/JSCJSValue.h:

(JSC::keepAlive):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• heap/HeapCell.cpp (modified) (1 diff)
• runtime/JSCJSValue.cpp (modified) (1 diff)
• runtime/JSCJSValue.h (modified) (1 diff)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2020-03-22  Yusuke Suzuki  <ysuzuki@apple.com>
+
+        [JSC] Add JSC::keepAlive(JSValue)
+        https://bugs.webkit.org/show_bug.cgi?id=209398
+
+        Reviewed by Mark Lam.
+
+        Add JSC::keepAlive(JSValue). This is useful to make some JSValue variable alive from GC.
+
+        * heap/HeapCell.cpp:
+        * runtime/JSCJSValue.cpp:
+        (JSC::keepAlive):
+        * runtime/JSCJSValue.h:
+        (JSC::keepAlive):
+
 2020-03-20  Ross Kirsling  <ross.kirsling@sony.com>
 

trunk/Source/JavaScriptCore/heap/HeapCell.cpp

@@ -44 +44 @@
 
 #if !COMPILER(GCC_COMPATIBLE)
+// This makes the argument opaque from the compiler.
 NEVER_INLINE void keepAlive(const void*)
 {

trunk/Source/JavaScriptCore/runtime/JSCJSValue.cpp

@@ -428 +428 @@
 }
 
+#if !COMPILER(GCC_COMPATIBLE)
+// This makes the argument opaque from the compiler.
+NEVER_INLINE void keepAlive(JSValue)
+{
+}
+#endif
+
 } // namespace JSC

trunk/Source/JavaScriptCore/runtime/JSCJSValue.h

@@ -638 +638 @@
 bool sameValue(JSGlobalObject*, JSValue a, JSValue b);
 
+#if COMPILER(GCC_COMPATIBLE)
+ALWAYS_INLINE void keepAlive(JSValue value)
+{
+#if USE(JSVALUE64)
+    asm volatile ("" : : "r"(bitwise_cast<uint64_t>(value)) : "memory");
+#else
+    asm volatile ("" : : "r"(value.payload()) : "memory");
+#endif
+}
+#else
+JS_EXPORT_PRIVATE void keepAlive(JSValue);
+#endif
+
 } // namespace JSC