Changeset 34319 in webkit for trunk/JavaScriptCore/VM/CodeGenerator.cpp

Timestamp:

Jun 2, 2008, 1:45:13 PM (17 years ago)

Author:

[email protected]

Message:

2008-06-02 Geoffrey Garen <​[email protected]>

Reviewed by Darin Adler.

A little cleanup in the CodeGenerator.

• VM/CodeGenerator.cpp: A few changes here.

(1) Removed remaining cases of the old hack of putting "this" into the
symbol table; replaced with explicit tracking of m_thisRegister.

(2) Made m_thisRegister behave the same for function, eval, and program
code, removing the static programCodeThis() function.

(3) Added a feature to nix a ScopeNode's declaration stacks when done
compiling, to save memory.

(4) Removed code that copied eval declarations into special vectors: we
just use the originals in the ScopeNode now.

• VM/CodeGenerator.h: Removed unneded parameters from the CodeGenerator constructor: we just use get that data from the ScopeNode now.

• VM/Machine.cpp: (KJS::Machine::execute): When executing an eval node, don't iterate a special copy of its declarations; iterate the originals, instead.

• kjs/nodes.cpp: Moved responsibility for knowing what AST data to throw away into the CodeGenerator. Nodes no longer call shrinkCapacity on their data directly.

• kjs/nodes.h: Changed FunctionStack to ref its contents, so declaration data stays around even after we've thrown away the AST, unless we explicitly throw away the declaration data, too. This is useful for eval code, which needs to reference its declaration data at execution time. (Soon, it will be useful for program code, too, since program code should do the same.)

File:

• trunk/JavaScriptCore/VM/CodeGenerator.cpp (modified) (15 diffs)

trunk/JavaScriptCore/VM/CodeGenerator.cpp

@@ -130 +130 @@
 {
     m_codeBlock->numLocals = m_codeBlock->numVars + m_codeBlock->numParameters;
-    m_codeBlock->thisRegister = m_codeType == FunctionCode ? -m_codeBlock->numLocals : Machine::ProgramCodeThisRegister;
+    m_codeBlock->thisRegister = m_thisRegister.index();
     if (m_shouldEmitDebugHooks)
         m_codeBlock->needsFullScopeChain = true;
@@ -143 +143 @@
 #endif
 
-    // Remove "this" from symbol table so it does not appear as a global object property at runtime.
-    symbolTable().remove(m_propertyNames->thisIdentifier.ustring().rep());
+    m_scopeNode->children().shrinkCapacity(0);
+    if (m_codeType != EvalCode) { // eval code needs to hang on to its declaration stacks to keep declaration info alive until Machine::execute time.
+        m_scopeNode->varStack().shrinkCapacity(0);
+        m_scopeNode->functionStack().shrinkCapacity(0);
+    }
 }
 
@@ -164 +167 @@
     r0 = &m_locals[localsIndex(index)];
     return result.second;
-}
-
-RegisterID* CodeGenerator::programCodeThis()
-{
-    static RegisterID programThis(Machine::ProgramCodeThisRegister);
-    return &programThis;
 }
 
@@ -178 +175 @@
     , m_scopeNode(programNode)
     , m_codeBlock(codeBlock)
+    , m_thisRegister(Machine::ProgramCodeThisRegister)
     , m_finallyDepth(0)
     , m_dynamicScopeDepth(0)
@@ -184 +182 @@
     , m_nextVar(-1)
     , m_propertyNames(CommonIdentifiers::shared())
-
 {
     // Global code can inherit previously defined symbols.
     int size = symbolTable->size() + 1; // + 1 slot for  "this"
-    m_thisRegister = programCodeThis();
 
     // Add previously defined symbols to bookkeeping.
@@ -202 +198 @@
     
     ExecState* exec = globalObject->globalExec();
+    
+    // FIXME: Move the execution-related parts of this code to Machine::execute.
 
     if (canCreateVariables) {
         for (size_t i = 0; i < functionStack.size(); ++i) {
-            FuncDeclNode* funcDecl = functionStack[i];
+            FuncDeclNode* funcDecl = functionStack[i].get();
             globalObject->removeDirect(funcDecl->m_ident); // Make sure our new function is not shadowed by an old property.
             emitNewFunction(addVar(funcDecl->m_ident, false), funcDecl);
@@ -216 +214 @@
     } else {
         for (size_t i = 0; i < functionStack.size(); ++i) {
-            FuncDeclNode* funcDecl = functionStack[i];
+            FuncDeclNode* funcDecl = functionStack[i].get();
             globalObject->putWithAttributes(exec, funcDecl->m_ident, funcDecl->makeFunction(exec, scopeChain.node()), DontDelete);
         }
@@ -230 +228 @@
 }
 
-CodeGenerator::CodeGenerator(FunctionBodyNode* functionBody, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, CodeBlock* codeBlock, VarStack& varStack, FunctionStack& functionStack, Vector<Identifier>& parameters)
+CodeGenerator::CodeGenerator(FunctionBodyNode* functionBody, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, CodeBlock* codeBlock)
     : m_shouldEmitDebugHooks(!!debugger)
     , m_scopeChain(&scopeChain)
@@ -236 +234 @@
     , m_scopeNode(functionBody)
     , m_codeBlock(codeBlock)
-    , m_thisRegister(0)
     , m_finallyDepth(0)
     , m_dynamicScopeDepth(0)
@@ -244 +241 @@
     , m_propertyNames(CommonIdentifiers::shared())
 {
+    const Node::FunctionStack& functionStack = functionBody->functionStack();
     for (size_t i = 0; i < functionStack.size(); ++i) {
-        FuncDeclNode* funcDecl = functionStack[i];
+        FuncDeclNode* funcDecl = functionStack[i].get();
         const Identifier& ident = funcDecl->m_ident;
         
@@ -252 +250 @@
     }
 
+    const Node::VarStack& varStack = functionBody->varStack();
     for (size_t i = 0; i < varStack.size(); ++i) {
         const Identifier& ident = varStack[i].first;
@@ -262 +261 @@
     }
 
-    m_nextParameter = m_nextVar - parameters.size();
-    m_locals.resize(localsIndex(m_nextParameter) + 1);
-
-    m_thisRegister = addParameter(m_propertyNames->thisIdentifier);
-    for (size_t i = 0; i < parameters.size(); ++i) {
+    Vector<Identifier>& parameters = functionBody->parameters();
+    m_nextParameter = m_nextVar - parameters.size(); // parameters are allocated prior to vars
+    m_locals.resize(localsIndex(m_nextParameter) + 1); // localsIndex of 0 => m_locals size of 1
+
+    // Add "this" as a parameter
+    m_thisRegister.setIndex(m_nextParameter);
+    ++m_nextParameter;
+    ++m_codeBlock->numParameters;
+    
+    for (size_t i = 0; i < parameters.size(); ++i)
         addParameter(parameters[i]);
-    }
-}
-
-CodeGenerator::CodeGenerator(EvalNode* evalNode, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, EvalCodeBlock* codeBlock, VarStack& varStack, FunctionStack& functionStack)
+}
+
+CodeGenerator::CodeGenerator(EvalNode* evalNode, const Debugger* debugger, const ScopeChain& scopeChain, SymbolTable* symbolTable, EvalCodeBlock* codeBlock)
     : m_shouldEmitDebugHooks(!!debugger)
     , m_scopeChain(&scopeChain)
@@ -277 +280 @@
     , m_scopeNode(evalNode)
     , m_codeBlock(codeBlock)
-    , m_thisRegister(0)
+    , m_thisRegister(Machine::ProgramCodeThisRegister)
     , m_finallyDepth(0)
     , m_dynamicScopeDepth(0)
@@ -285 +288 @@
     , m_propertyNames(CommonIdentifiers::shared())
 {
-    addVar(m_propertyNames->thisIdentifier, m_thisRegister, false);
-    
-    for (size_t i = 0; i < varStack.size(); ++i)
-        codeBlock->declaredVariableNames.append(varStack[i].first);
-    
-    for (size_t i = 0; i < functionStack.size(); ++i) {
-        FuncDeclNode* funcDecl = functionStack[i];
-        codeBlock->declaredFunctionNames.append(funcDecl->m_ident);
-        addConstant(funcDecl);
-    }
+    m_codeBlock->numVars = 1; // Allocate space for "this"
 }
 
@@ -325 +319 @@
         m_codeBlock->needsFullScopeChain = true;
 
-    if (!shouldOptimizeLocals() && ident != m_propertyNames->thisIdentifier)
+    if (ident == m_propertyNames->thisIdentifier)
+        return &m_thisRegister;
+
+    if (!shouldOptimizeLocals())
         return 0;