Changeset 58986 in webkit for trunk/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

Timestamp:

May 7, 2010, 5:05:00 PM (15 years ago)

Author:

[email protected]

Message:

2010-05-07 Oliver Hunt <​[email protected]>

Reviewed by Geoffrey Garen.

Optimize access to the global object from a function that uses eval
​https://bugs.webkit.org/show_bug.cgi?id=38644

Add op_resolve_global_dynamic, a variant of op_resolve_global that
checks each node in the scope chain for dynamically inserted properties
and falls back to the normal resolve logic in that case.

• JavaScriptCore.exp:
• bytecode/CodeBlock.cpp: (JSC::isGlobalResolve): (JSC::CodeBlock::printStructures): (JSC::CodeBlock::dump): (JSC::CodeBlock::derefStructures):
• bytecode/Opcode.h:
• bytecompiler/BytecodeGenerator.cpp: (JSC::BytecodeGenerator::findScopedProperty):

Now take an additional reference parameter to used to indicate that
there were nodes that may gain dynamic properties

(JSC::BytecodeGenerator::emitResolve):
(JSC::BytecodeGenerator::emitResolveBase):
(JSC::BytecodeGenerator::emitResolveWithBase):

deal with additional argument to findScopedProperty

• bytecompiler/BytecodeGenerator.h:
• bytecompiler/NodesCodegen.cpp: (JSC::FunctionCallResolveNode::emitBytecode): (JSC::PostfixResolveNode::emitBytecode): (JSC::PrefixResolveNode::emitBytecode): (JSC::ReadModifyResolveNode::emitBytecode): (JSC::AssignResolveNode::emitBytecode):

These functions use findScopedProperty directly in order to
optimise lookup. They cannot trivially handle any degree of
dynamism in the lookup so we just give up in such case.

• interpreter/Interpreter.cpp: (JSC::Interpreter::resolveGlobalDynamic): (JSC::Interpreter::execute): (JSC::Interpreter::privateExecute):
• interpreter/Interpreter.h:
• jit/JIT.cpp: (JSC::JIT::privateCompileMainPass): (JSC::JIT::privateCompileSlowCases):
• jit/JIT.h:
• jit/JITOpcodes.cpp: (JSC::JIT::emit_op_resolve_global): (JSC::JIT::emit_op_resolve_global_dynamic): (JSC::JIT::emitSlow_op_resolve_global): (JSC::JIT::emitSlow_op_resolve_global_dynamic):

Happily resolve_global_dynamic can share the slow case!

• jit/JITStubs.h: (JSC::):
• runtime/JSActivation.cpp: (JSC::JSActivation::isDynamicScope):
• runtime/JSActivation.h:
• runtime/JSGlobalObject.cpp: (JSC::JSGlobalObject::isDynamicScope):
• runtime/JSGlobalObject.h:
• runtime/JSStaticScopeObject.cpp: (JSC::JSStaticScopeObject::isDynamicScope):
• runtime/JSStaticScopeObject.h:
• runtime/JSVariableObject.h:

File:

• trunk/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp (modified) (10 diffs)

trunk/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

@@ -994 +994 @@
 }
 
-bool BytecodeGenerator::findScopedProperty(const Identifier& property, int& index, size_t& stackDepth, bool forWriting, JSObject*& globalObject)
+bool BytecodeGenerator::findScopedProperty(const Identifier& property, int& index, size_t& stackDepth, bool forWriting, bool& requiresDynamicChecks, JSObject*& globalObject)
 {
     // Cases where we cannot statically optimize the lookup.
@@ -1010 +1010 @@
 
     size_t depth = 0;
-    
+    requiresDynamicChecks = false;
     ScopeChainIterator iter = m_scopeChain->begin();
     ScopeChainIterator end = m_scopeChain->end();
@@ -1035 +1035 @@
             return true;
         }
-        if (currentVariableObject->isDynamicScope())
+        bool scopeRequiresDynamicChecks = false;
+        if (currentVariableObject->isDynamicScope(scopeRequiresDynamicChecks))
             break;
-    }
-
+        requiresDynamicChecks |= scopeRequiresDynamicChecks;
+    }
     // Can't locate the property but we're able to avoid a few lookups.
     stackDepth = depth;
@@ -1063 +1064 @@
     int index = 0;
     JSObject* globalObject = 0;
-    if (!findScopedProperty(property, index, depth, false, globalObject) && !globalObject) {
+    bool requiresDynamicChecks = false;
+    if (!findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject) && !globalObject) {
         // We can't optimise at all :-(
         emitOpcode(op_resolve);
@@ -1091 +1093 @@
         m_codeBlock->addGlobalResolveInstruction(instructions().size());
 #endif
-        emitOpcode(op_resolve_global);
+        emitOpcode(requiresDynamicChecks ? op_resolve_global_dynamic : op_resolve_global);
         instructions().append(dst->index());
         instructions().append(globalObject);
@@ -1097 +1099 @@
         instructions().append(0);
         instructions().append(0);
+        if (requiresDynamicChecks)
+            instructions().append(depth);
+        return dst;
+    }
+
+    if (requiresDynamicChecks) {
+        // If we get here we have eval nested inside a |with| just give up
+        emitOpcode(op_resolve);
+        instructions().append(dst->index());
+        instructions().append(addConstant(property));
         return dst;
     }
@@ -1152 +1164 @@
     int index = 0;
     JSObject* globalObject = 0;
-    findScopedProperty(property, index, depth, false, globalObject);
-    if (!globalObject) {
+    bool requiresDynamicChecks = false;
+    findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject);
+    if (!globalObject || requiresDynamicChecks) {
         // We can't optimise at all :-(
         emitOpcode(op_resolve_base);
@@ -1170 +1183 @@
     int index = 0;
     JSObject* globalObject = 0;
-    if (!findScopedProperty(property, index, depth, false, globalObject) || !globalObject) {
+    bool requiresDynamicChecks = false;
+    if (!findScopedProperty(property, index, depth, false, requiresDynamicChecks, globalObject) || !globalObject || requiresDynamicChecks) {
         // We can't optimise at all :-(
         emitOpcode(op_resolve_with_base);
@@ -1202 +1216 @@
     m_codeBlock->addGlobalResolveInstruction(instructions().size());
 #endif
-    emitOpcode(op_resolve_global);
+    emitOpcode(requiresDynamicChecks ? op_resolve_global_dynamic : op_resolve_global);
     instructions().append(propDst->index());
     instructions().append(globalObject);
@@ -1208 +1222 @@
     instructions().append(0);
     instructions().append(0);
+    if (requiresDynamicChecks)
+        instructions().append(depth);
     return baseDst;
 }