Changeset 127810 in webkit for trunk/Source/JavaScriptCore/bytecompiler

Timestamp:

Sep 6, 2012, 6:42:53 PM (13 years ago)

Author:

[email protected]

Message:

Source/JavaScriptCore: Rolled back in <​http://trac.webkit.org/changeset/127698> with a fix for
fast/dom/HTMLScriptElement/script-reexecution-pretty-diff.html, which
is to make sure that function declarations don't put their names in scope.

Reviewed by Gavin Barraclough.

Named functions should not allocate scope objects for their names
​https://bugs.webkit.org/show_bug.cgi?id=95659

Reviewed by Oliver Hunt.

LayoutTests: Rolled back in <​http://trac.webkit.org/changeset/127698> with a fix for
fast/dom/HTMLScriptElement/script-reexecution-pretty-diff.html.

Added a more explicit test for the feature I broke in
fast/dom/HTMLScriptElement/script-reexecution-pretty-diff.html.

Reviewed by Gavin Barraclough.

Named functions should not allocate scope objects for their names
​https://bugs.webkit.org/show_bug.cgi?id=95659

Reviewed by Oliver Hunt.

• fast/dom/HTMLScriptElement/script-reexecution.html:
• fast/js/function-name-is-in-scope-expected.txt: Added.
• fast/js/function-name-is-in-scope.html: Added.

Location:

trunk/Source/JavaScriptCore/bytecompiler

Files:

• BytecodeGenerator.cpp (modified) (11 diffs)
• BytecodeGenerator.h (modified) (4 diffs)

trunk/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp

@@ -34 +34 @@
 #include "BatchedTransitionOptimizer.h"
 #include "Comment.h"
+#include "Interpreter.h"
 #include "JSActivation.h"
 #include "JSFunction.h"
-#include "Interpreter.h"
+#include "JSNameScope.h"
 #include "LowLevelInterpreter.h"
-
 #include "StrongInlines.h"
 #include <wtf/text/WTFString.h>
@@ -325 +325 @@
             globalObject->removeDirect(*m_globalData, function->ident()); // Newly declared functions overwrite existing properties.
         
-        JSValue value = JSFunction::create(exec, makeFunction(exec, function), scope);
+        JSValue value = JSFunction::create(exec, FunctionExecutable::create(*m_globalData, function), scope);
         int index = addGlobalVar(
             function->ident(), IsVariable,
@@ -420 +420 @@
     }
 
+    RegisterID* calleeRegister = resolveCallee(functionBody); // May push to the scope chain and/or add a captured var.
+
     const DeclarationStacks::FunctionStack& functionStack = functionBody->functionStack();
     const DeclarationStacks::VarStack& varStack = functionBody->varStack();
@@ -457 +459 @@
 
     codeBlock->m_numCapturedVars = codeBlock->m_numVars;
+
     m_firstLazyFunction = codeBlock->m_numVars;
     for (size_t i = 0; i < functionStack.size(); ++i) {
@@ -497 +500 @@
 
     preserveLastVar();
+
+    // We declare the callee's name last because it should lose to a var, function, and/or parameter declaration.
+    addCallee(functionBody, calleeRegister);
 
     if (isConstructor()) {
@@ -550 +556 @@
     const DeclarationStacks::FunctionStack& functionStack = evalNode->functionStack();
     for (size_t i = 0; i < functionStack.size(); ++i)
-        m_codeBlock->addFunctionDecl(makeFunction(m_globalData, functionStack[i]));
+        m_codeBlock->addFunctionDecl(FunctionExecutable::create(*m_globalData, functionStack[i]));
 
     const DeclarationStacks::VarStack& varStack = evalNode->varStack();
@@ -573 +579 @@
     instructions().append(reg->index());
     return reg;
+}
+
+RegisterID* BytecodeGenerator::resolveCallee(FunctionBodyNode* functionBodyNode)
+{
+    if (functionBodyNode->ident().isNull() || !functionBodyNode->functionNameIsInScope())
+        return 0;
+
+    m_calleeRegister.setIndex(RegisterFile::Callee);
+
+    // If non-strict eval is in play, we use a separate object in the scope chain for the callee's name.
+    if ((m_codeBlock->usesEval() && !m_codeBlock->isStrictMode()) || m_shouldEmitDebugHooks) {
+        emitOpcode(op_push_name_scope);
+        instructions().append(addConstant(functionBodyNode->ident()));
+        instructions().append(m_calleeRegister.index());
+        instructions().append(ReadOnly | DontDelete);
+
+        // Put a mirror object in compilation scope, so compile-time variable resolution sees the property name we'll see at runtime.
+        m_scope.set(*globalData(),
+            JSNameScope::create(
+                m_scope->globalObject()->globalExec(),
+                functionBodyNode->ident(),
+                jsUndefined(),
+                ReadOnly | DontDelete,
+                m_scope.get()
+            )
+        );
+        return 0;
+    }
+
+    if (!functionBodyNode->captures(functionBodyNode->ident()))
+        return &m_calleeRegister;
+
+    // Move the callee into the captured section of the stack.
+    return emitMove(addVar(), &m_calleeRegister);
+}
+
+void BytecodeGenerator::addCallee(FunctionBodyNode* functionBodyNode, RegisterID* calleeRegister)
+{
+    if (functionBodyNode->ident().isNull() || !functionBodyNode->functionNameIsInScope())
+        return;
+
+    // If non-strict eval is in play, we use a separate object in the scope chain for the callee's name.
+    if ((m_codeBlock->usesEval() && !m_codeBlock->isStrictMode()) || m_shouldEmitDebugHooks)
+        return;
+
+    ASSERT(calleeRegister);
+    symbolTable().add(functionBodyNode->ident().impl(), SymbolTableEntry(calleeRegister->index(), ReadOnly));
 }
 
@@ -1831 +1884 @@
 RegisterID* BytecodeGenerator::emitNewFunction(RegisterID* dst, FunctionBodyNode* function)
 {
-    return emitNewFunctionInternal(dst, m_codeBlock->addFunctionDecl(makeFunction(m_globalData, function)), false);
+    return emitNewFunctionInternal(dst, m_codeBlock->addFunctionDecl(FunctionExecutable::create(*m_globalData, function)), false);
 }
 
@@ -1838 +1891 @@
     FunctionOffsetMap::AddResult ptr = m_functionOffsets.add(function, 0);
     if (ptr.isNewEntry)
-        ptr.iterator->second = m_codeBlock->addFunctionDecl(makeFunction(m_globalData, function));
+        ptr.iterator->second = m_codeBlock->addFunctionDecl(FunctionExecutable::create(*m_globalData, function));
     return emitNewFunctionInternal(dst, ptr.iterator->second, true);
 }
@@ -1863 +1916 @@
 {
     FunctionBodyNode* function = n->body();
-    unsigned index = m_codeBlock->addFunctionExpr(makeFunction(m_globalData, function));
+    unsigned index = m_codeBlock->addFunctionExpr(FunctionExecutable::create(*m_globalData, function));
     
     createActivationIfNecessary();
@@ -2600 +2653 @@
         return;
 
-    RefPtr<RegisterID> error = emitLoad(newTemporary(), createTypeError(scope()->globalObject()->globalExec(), StrictModeReadonlyPropertyWriteError));
+    RefPtr<RegisterID> error = emitLoad(newTemporary(), JSValue(createTypeError(scope()->globalObject()->globalExec(), StrictModeReadonlyPropertyWriteError)));
     emitThrow(error.get());
 }

trunk/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.h

@@ -618 +618 @@
 
         void addParameter(const Identifier&, int parameterIndex);
-        
+        RegisterID* resolveCallee(FunctionBodyNode*);
+        void addCallee(FunctionBodyNode*, RegisterID*);
+
         void preserveLastVar();
         bool shouldAvoidResolveGlobal();
@@ -626 +628 @@
             if (index >= 0)
                 return m_calleeRegisters[index];
+
+            if (index == RegisterFile::Callee)
+                return m_calleeRegister;
 
             ASSERT(m_parameters.size());
@@ -637 +642 @@
         unsigned addConstantBuffer(unsigned length);
         
-        FunctionExecutable* makeFunction(ExecState* exec, FunctionBodyNode* body)
-        {
-            return FunctionExecutable::create(exec, body->ident(), body->inferredName(), body->source(), body->usesArguments(), body->parameters(), body->isStrictMode(), body->lineNo(), body->lastLine());
-        }
-
-        FunctionExecutable* makeFunction(JSGlobalData* globalData, FunctionBodyNode* body)
-        {
-            return FunctionExecutable::create(*globalData, body->ident(), body->inferredName(), body->source(), body->usesArguments(), body->parameters(), body->isStrictMode(), body->lineNo(), body->lastLine());
-        }
-
         JSString* addStringConstant(const Identifier&);
 
@@ -717 +712 @@
         RegisterID m_ignoredResultRegister;
         RegisterID m_thisRegister;
+        RegisterID m_calleeRegister;
         RegisterID* m_activationRegister;
         SegmentedVector<RegisterID, 32> m_constantPoolRegisters;