Changeset 241557 in webkit for trunk/Source/JavaScriptCore/runtime/VM.cpp

Timestamp:

Feb 14, 2019, 11:10:15 AM (6 years ago)

Author:

[email protected]

Message:

[JSC] Should have default NativeJITCode
​https://bugs.webkit.org/show_bug.cgi?id=194634

Reviewed by Mark Lam.

In JSC_useJIT=false mode, we always create identical NativeJITCode for call and construct when we create NativeExecutable.
This is meaningless since we do not modify NativeJITCode after the creation. This patch adds singleton used as a default one.
Since NativeJITCode (& JITCode) is ThreadSafeRefCounted, we can just share it in a whole process level. This removes 446 NativeJITCode
allocations, which takes 14KB.

• runtime/VM.cpp:

(JSC::jitCodeForCallTrampoline):
(JSC::jitCodeForConstructTrampoline):
(JSC::VM::getHostFunction):

File:

• trunk/Source/JavaScriptCore/runtime/VM.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/runtime/VM.cpp

@@ -689 +689 @@
 }
 
+static Ref<NativeJITCode> jitCodeForCallTrampoline()
+{
+    static NativeJITCode* result;
+    static std::once_flag onceKey;
+    std::call_once(onceKey, [&] {
+        result = new NativeJITCode(LLInt::getCodeRef<JSEntryPtrTag>(llint_native_call_trampoline), JITCode::HostCallThunk, NoIntrinsic);
+    });
+    return makeRef(*result);
+}
+
+static Ref<NativeJITCode> jitCodeForConstructTrampoline()
+{
+    static NativeJITCode* result;
+    static std::once_flag onceKey;
+    std::call_once(onceKey, [&] {
+        result = new NativeJITCode(LLInt::getCodeRef<JSEntryPtrTag>(llint_native_construct_trampoline), JITCode::HostCallThunk, NoIntrinsic);
+    });
+    return makeRef(*result);
+}
+
 NativeExecutable* VM::getHostFunction(NativeFunction function, Intrinsic intrinsic, NativeFunction constructor, const DOMJIT::Signature* signature, const String& name)
 {
@@ -701 +721 @@
     UNUSED_PARAM(intrinsic);
     UNUSED_PARAM(signature);
-
-    return NativeExecutable::create(*this,
-        adoptRef(*new NativeJITCode(LLInt::getCodeRef<JSEntryPtrTag>(llint_native_call_trampoline), JITCode::HostCallThunk, NoIntrinsic)), function,
-        adoptRef(*new NativeJITCode(LLInt::getCodeRef<JSEntryPtrTag>(llint_native_construct_trampoline), JITCode::HostCallThunk, NoIntrinsic)), constructor,
-        name);
+    return NativeExecutable::create(*this, jitCodeForCallTrampoline(), function, jitCodeForConstructTrampoline(), constructor, name);
 }