Changeset 49820 in webkit for trunk/JavaScriptCore/jit/JITPropertyAccess.cpp

Timestamp:

Oct 19, 2009, 3:59:41 PM (16 years ago)

Author:

[email protected]

Message:

Tightened up some put_by_id_transition code generation.
​https://bugs.webkit.org/show_bug.cgi?id=30539

Patch by Geoffrey Garen <​[email protected]> on 2009-10-19
Reviewed by Oliver Hunt.

• jit/JIT.h:
• jit/JITPropertyAccess.cpp:

(JSC::JIT::testPrototype):
(JSC::JIT::privateCompilePutByIdTransition): No need to do object type
checks or read Structures and prototypes from objects: they're all known
constants at compile time.

File:

• trunk/JavaScriptCore/jit/JITPropertyAccess.cpp (modified) (4 diffs)

trunk/JavaScriptCore/jit/JITPropertyAccess.cpp

@@ -522 +522 @@
 }
 
+void JIT::testPrototype(Structure* structure, JumpList& failureCases)
+{
+    if (structure->m_prototype.isNull())
+        return;
+
+    failureCases.append(branchPtr(NotEqual, AbsoluteAddress(&asCell(structure->m_prototype)->m_structure), ImmPtr(asCell(structure->m_prototype)->m_structure)));
+}
+
 void JIT::privateCompilePutByIdTransition(StructureStubInfo* stubInfo, Structure* oldStructure, Structure* newStructure, size_t cachedOffset, StructureChain* chain, ReturnAddressPtr returnAddress)
 {
@@ -528 +536 @@
     JumpList failureCases;
     failureCases.append(branch32(NotEqual, regT1, Imm32(JSValue::CellTag)));
-
-    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), regT2);
-    failureCases.append(branchPtr(NotEqual, regT2, ImmPtr(oldStructure)));
+    failureCases.append(branchPtr(NotEqual, Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), ImmPtr(oldStructure)));
+    testPrototype(oldStructure, failureCases);
 
     // Verify that nothing in the prototype chain has a setter for this property. 
-    for (RefPtr<Structure>* it = chain->head(); *it; ++it) {
-        loadPtr(Address(regT2, OBJECT_OFFSETOF(Structure, m_prototype)), regT2);
-        loadPtr(Address(regT2, OBJECT_OFFSETOF(JSCell, m_structure)), regT2);
-        failureCases.append(branchPtr(NotEqual, regT2, ImmPtr(it->get())));
-    }
+    for (RefPtr<Structure>* it = chain->head(); *it; ++it)
+        testPrototype(it->get(), failureCases);
 
     // Reallocate property storage if needed.
@@ -1348 +1352 @@
 }
 
+void JIT::testPrototype(Structure* structure, JumpList& failureCases)
+{
+    if (structure->m_prototype.isNull())
+        return;
+
+    move(ImmPtr(&asCell(structure->m_prototype)->m_structure), regT2);
+    move(ImmPtr(asCell(structure->m_prototype)->m_structure), regT3);
+    failureCases.append(branchPtr(NotEqual, Address(regT2), regT3));
+}
+
 void JIT::privateCompilePutByIdTransition(StructureStubInfo* stubInfo, Structure* oldStructure, Structure* newStructure, size_t cachedOffset, StructureChain* chain, ReturnAddressPtr returnAddress)
 {
@@ -1354 +1368 @@
     failureCases.append(emitJumpIfNotJSCell(regT0));
     failureCases.append(branchPtr(NotEqual, Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), ImmPtr(oldStructure)));
-    JumpList successCases;
-
-    // ecx = baseObject
-    loadPtr(Address(regT0, OBJECT_OFFSETOF(JSCell, m_structure)), regT2);
-    // proto(ecx) = baseObject->structure()->prototype()
-    failureCases.append(branch32(NotEqual, Address(regT2, OBJECT_OFFSETOF(Structure, m_typeInfo) + OBJECT_OFFSETOF(TypeInfo, m_type)), Imm32(ObjectType)));
-
-    loadPtr(Address(regT2, OBJECT_OFFSETOF(Structure, m_prototype)), regT2);
-    
+    testPrototype(oldStructure, failureCases);
+
     // ecx = baseObject->m_structure
-    for (RefPtr<Structure>* it = chain->head(); *it; ++it) {
-        // null check the prototype
-        successCases.append(branchPtr(Equal, regT2, ImmPtr(JSValue::encode(jsNull()))));
-
-        // Check the structure id
-        failureCases.append(branchPtr(NotEqual, Address(regT2, OBJECT_OFFSETOF(JSCell, m_structure)), ImmPtr(it->get())));
-        
-        loadPtr(Address(regT2, OBJECT_OFFSETOF(JSCell, m_structure)), regT2);
-        failureCases.append(branch32(NotEqual, Address(regT2, OBJECT_OFFSETOF(Structure, m_typeInfo) + OBJECT_OFFSETOF(TypeInfo, m_type)), Imm32(ObjectType)));
-        loadPtr(Address(regT2, OBJECT_OFFSETOF(Structure, m_prototype)), regT2);
-    }
-
-    successCases.link(this);
+    for (RefPtr<Structure>* it = chain->head(); *it; ++it)
+        testPrototype(it->get(), failureCases);
 
     Call callTarget;