Changeset 37366 in webkit for trunk/JavaScriptCore/VM/Machine.cpp

Timestamp:

Oct 6, 2008, 8:53:47 PM (17 years ago)

Author:

[email protected]

Message:

2008-10-06 Cameron Zwarich <​[email protected]>

Reviewed by Oliver Hunt.

Bug 21396: Remove the OptionalCalleeActivation call frame slot
<​https://bugs.webkit.org/show_bug.cgi?id=21396>

Remove the OptionalCalleeActivation call frame slot. We have to be
careful to store the activation object in a register, because objects
in the scope chain do not get marked.

This is a 0.3% speedup on both SunSpider and the V8 benchmark.

• VM/CTI.cpp: (JSC::CTI::privateCompileMainPass):
• VM/CodeBlock.cpp: (JSC::CodeBlock::dump):
• VM/CodeGenerator.cpp: (JSC::CodeGenerator::CodeGenerator): (JSC::CodeGenerator::emitReturn):
• VM/CodeGenerator.h:
• VM/Machine.cpp: (JSC::Machine::dumpRegisters): (JSC::Machine::unwindCallFrame): (JSC::Machine::privateExecute): (JSC::Machine::cti_op_call_JSFunction): (JSC::Machine::cti_op_push_activation): (JSC::Machine::cti_op_tear_off_activation): (JSC::Machine::cti_op_construct_JSConstruct):
• VM/Machine.h: (JSC::Machine::initializeCallFrame):
• VM/RegisterFile.h: (JSC::RegisterFile::):

File:

• trunk/JavaScriptCore/VM/Machine.cpp (modified) (11 diffs)

trunk/JavaScriptCore/VM/Machine.cpp

@@ -702 +702 @@
     printf("[ArgumentCount]            | %10p | %10p \n", it, (*it).v()); ++it;
     printf("[Callee]                   | %10p | %10p \n", it, (*it).v()); ++it;
-    printf("[OptionalCalleeActivation] | %10p | %10p \n", it, (*it).v()); ++it;
     printf("[OptionalCalleeArguments]  | %10p | %10p \n", it, (*it).v()); ++it;
     printf("----------------------------------------------------\n");
@@ -776 +775 @@
     }
 
-    if (oldCodeBlock->needsFullScopeChain)
-        scopeChain->deref();
-
     // If this call frame created an activation or an 'arguments' object, tear it off.
-    if (JSActivation* activation = static_cast<JSActivation*>(r[RegisterFile::OptionalCalleeActivation].getJSValue())) {
+    if (oldCodeBlock->codeType == FunctionCode && oldCodeBlock->needsFullScopeChain) {
+        while (!scopeChain->object->isObject(&JSActivation::info))
+            scopeChain = scopeChain->pop();
+        JSActivation* activation = static_cast<JSActivation*>(scopeChain->object);
         ASSERT(activation->isObject(&JSActivation::info));
+
         Arguments* arguments = static_cast<Arguments*>(r[RegisterFile::OptionalCalleeArguments].getJSValue());
         ASSERT(!arguments || arguments->isObject(&Arguments::info));
+
         activation->copyRegisters(arguments);
     } else if (Arguments* arguments = static_cast<Arguments*>(r[RegisterFile::OptionalCalleeArguments].getJSValue())) {
@@ -790 +791 @@
             arguments->copyRegisters();
     }
-    
+
+    if (oldCodeBlock->needsFullScopeChain)
+        scopeChain->deref();
+
     void* returnPC = r[RegisterFile::ReturnPC].v();
     r = r[RegisterFile::CallerRegisters].r();
@@ -3357 +3361 @@
     }
     BEGIN_OPCODE(op_tear_off_activation) {
-        JSActivation* activation = static_cast<JSActivation*>(r[RegisterFile::OptionalCalleeActivation].getJSValue());
+        int src = (++vPC)->u.operand;
+        JSActivation* activation = static_cast<JSActivation*>(r[src].getJSValue());
         ASSERT(codeBlock(r)->needsFullScopeChain);
         ASSERT(activation->isObject(&JSActivation::info));
@@ -3433 +3438 @@
     }
     BEGIN_OPCODE(op_enter_with_activation) {
-        /* enter_with_activation
+        /* enter_with_activation dst(r)
 
            Initializes local variables to undefined, fills constant
            registers with their values, creates an activation object,
-           and places the new activation both in the activation slot
-           in the call frame and at the top of the scope chain. If the
-           code block does not require an activation, enter should be
-           used instead.
+           and places the new activation both in dst and at the top
+           of the scope chain. If the code block does not require an
+           activation, enter should be used instead.
 
            This opcode should only be used at the beginning of a code
@@ -3455 +3459 @@
             r[i] = codeBlock->constantRegisters[j];
 
+        int dst = (++vPC)->u.operand;
         JSActivation* activation = new (globalData) JSActivation(exec, static_cast<FunctionBodyNode*>(codeBlock->ownerNode), r);
-        r[RegisterFile::OptionalCalleeActivation] = activation;
+        r[dst] = activation;
         r[RegisterFile::ScopeChain] = scopeChain(r)->copy()->push(activation);
 
@@ -4582 +4587 @@
     r[RegisterFile::ArgumentCount] = ARG_int3; // original argument count (for the sake of the "arguments" object)
     r[RegisterFile::Callee] = ARG_src1;
-    r[RegisterFile::OptionalCalleeActivation] = nullJSValue;
     r[RegisterFile::OptionalCalleeArguments] = nullJSValue;
 
@@ -4601 +4605 @@
 }
 
-void Machine::cti_op_push_activation(CTI_ARGS)
+JSValue* Machine::cti_op_push_activation(CTI_ARGS)
 {
     ExecState* exec = ARG_exec;
@@ -4609 +4613 @@
 
     JSActivation* activation = new (ARG_globalData) JSActivation(exec, static_cast<FunctionBodyNode*>(codeBlock->ownerNode), r);
-    r[RegisterFile::OptionalCalleeActivation] = activation;
     r[RegisterFile::ScopeChain] = scopeChain->copy()->push(activation);
+    return activation;
 }
 
@@ -4669 +4673 @@
     Register* r = ARG_r;
 
-    JSActivation* activation = static_cast<JSActivation*>(r[RegisterFile::OptionalCalleeActivation].getJSValue());
+    JSActivation* activation = static_cast<JSActivation*>(ARG_src1);
     ASSERT(codeBlock(r)->needsFullScopeChain);
     ASSERT(activation->isObject(&JSActivation::info));
@@ -4786 +4790 @@
     r[RegisterFile::ArgumentCount] = argCount; // original argument count (for the sake of the "arguments" object)
     r[RegisterFile::Callee] = constructor;
-    r[RegisterFile::OptionalCalleeActivation] = nullJSValue;
     r[RegisterFile::OptionalCalleeArguments] = nullJSValue;