Changeset 36317 in webkit for trunk/JavaScriptCore/VM/CTI.cpp

Timestamp:

Sep 10, 2008, 2:23:35 AM (17 years ago)

Author:

[email protected]

Message:

Add optimised access to known properties on the global object.

Reviewed by Maciej Stachowiak

Improve cross scope access to the global object by emitting
code to access it directly rather than by walking the scope chain.

This is a 0.8% win in SunSpider and a 1.7% win in the v8 benchmarks.

File:

• trunk/JavaScriptCore/VM/CTI.cpp (modified) (4 diffs)

trunk/JavaScriptCore/VM/CTI.cpp

@@ -629 +629 @@
             break;
         }
+        case op_get_global_var: {
+            JSVariableObject* globalObject = static_cast<JSVariableObject*>(instruction[i + 2].u.jsCell);
+            m_jit.movl_i32r(reinterpret_cast<unsigned>(globalObject), X86::eax);
+            emitGetVariableObjectRegister(X86::eax, instruction[i + 3].u.operand, X86::eax);
+            emitPutResult(instruction[i + 1].u.operand, X86::eax);
+            i += 4;
+            break;
+        }
+        case op_put_global_var: {
+            JSVariableObject* globalObject = static_cast<JSVariableObject*>(instruction[i + 1].u.jsCell);
+            m_jit.movl_i32r(reinterpret_cast<unsigned>(globalObject), X86::eax);
+            emitGetArg(instruction[i + 3].u.operand, X86::edx);
+            emitPutVariableObjectRegister(X86::edx, X86::eax, instruction[i + 2].u.operand);
+            i += 4;
+            break;
+        }
         case op_get_scoped_var: {
             int skip = instruction[i + 3].u.operand + m_codeBlock->needsFullScopeChain;
@@ -637 +653 @@
 
             m_jit.movl_mr(OBJECT_OFFSET(ScopeChainNode, object), X86::eax, X86::eax);
-            m_jit.movl_mr(JSVariableObject::offsetOf_d(), X86::eax, X86::eax);
-            m_jit.movl_mr(JSVariableObject::offsetOf_Data_registers(), X86::eax, X86::eax);
-            m_jit.movl_mr((instruction[i + 2].u.operand) * sizeof(Register), X86::eax, X86::eax);
+            emitGetVariableObjectRegister(X86::eax, instruction[i + 2].u.operand, X86::eax);
             emitPutResult(instruction[i + 1].u.operand);
             i += 4;
@@ -653 +667 @@
 
             m_jit.movl_mr(OBJECT_OFFSET(ScopeChainNode, object), X86::edx, X86::edx);
-            m_jit.movl_mr(JSVariableObject::offsetOf_d(), X86::edx, X86::edx);
-            m_jit.movl_mr(JSVariableObject::offsetOf_Data_registers(), X86::edx, X86::edx);
-            m_jit.movl_rm(X86::eax, (instruction[i + 1].u.operand) * sizeof(Register), X86::edx);
+            emitPutVariableObjectRegister(X86::eax, X86::edx, instruction[i + 1].u.operand);
             i += 4;
             break;
@@ -1831 +1843 @@
 }
 
+void CTI::emitGetVariableObjectRegister(X86Assembler::RegisterID variableObject, int index, X86Assembler::RegisterID dst)
+{
+    m_jit.movl_mr(JSVariableObject::offsetOf_d(), variableObject, dst);
+    m_jit.movl_mr(JSVariableObject::offsetOf_Data_registers(), dst, dst);
+    m_jit.movl_mr(index * sizeof(Register), dst, dst);
+}
+
+void CTI::emitPutVariableObjectRegister(X86Assembler::RegisterID src, X86Assembler::RegisterID variableObject, int index)
+{
+    m_jit.movl_mr(JSVariableObject::offsetOf_d(), variableObject, variableObject);
+    m_jit.movl_mr(JSVariableObject::offsetOf_Data_registers(), variableObject, variableObject);
+    m_jit.movl_rm(src, index * sizeof(Register), variableObject);
+}
+
 #if ENABLE(WREC)