Remove unused LivenessAnalyzer class.

Also remove unused attributes related to it from the ast.
Review URL: http://codereview.chromium.org/1117003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4194 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ast.h

@@ -196,10 +196,7 @@ class Expression: public AstNode {
     kTestValue
   };
 
-  Expression()
-      : bitfields_(0),
-        def_(NULL),
-        defined_vars_(NULL) {}
+  Expression() : bitfields_(0) {}
 
   virtual Expression* AsExpression()  { return this; }
 
@@ -233,15 +230,6 @@ class Expression: public AstNode {
   // Static type information for this expression.
   StaticType* type() { return &type_; }
 
-  // Data flow information.
-  DefinitionInfo* var_def() { return def_; }
-  void set_var_def(DefinitionInfo* def) { def_ = def; }
-
-  ZoneList<DefinitionInfo*>* defined_vars() { return defined_vars_; }
-  void set_defined_vars(ZoneList<DefinitionInfo*>* defined_vars) {
-    defined_vars_ = defined_vars;
-  }
-
   // AST analysis results
 
   // True if the expression rooted at this node can be compiled by the
@@ -284,9 +272,6 @@ class Expression: public AstNode {
   uint32_t bitfields_;
   StaticType type_;
 
-  DefinitionInfo* def_;
-  ZoneList<DefinitionInfo*>* defined_vars_;
-
   // Using template BitField<type, start, size>.
   class SideEffectFreeField : public BitField<bool, 0, 1> {};
   class NoNegativeZeroField : public BitField<bool, 1, 1> {};

src/data-flow.cc

@@ -770,293 +770,6 @@ void AstLabeler::VisitDeclaration(Declaration* decl) {
 }
 
 
-ZoneList<Expression*>* VarUseMap::Lookup(Variable* var) {
-  HashMap::Entry* entry = HashMap::Lookup(var, var->name()->Hash(), true);
-  if (entry->value == NULL) {
-    entry->value = new ZoneList<Expression*>(1);
-  }
-  return reinterpret_cast<ZoneList<Expression*>*>(entry->value);
-}
-
-
-void LivenessAnalyzer::Analyze(FunctionLiteral* fun) {
-  // Process the function body.
-  VisitStatements(fun->body());
-
-  // All variables are implicitly defined at the function start.
-  // Record a definition of all variables live at function entry.
-  for (HashMap::Entry* p = live_vars_.Start();
-       p != NULL;
-       p = live_vars_.Next(p)) {
-    Variable* var = reinterpret_cast<Variable*>(p->key);
-    RecordDef(var, fun);
-  }
-}
-
-
-void LivenessAnalyzer::VisitStatements(ZoneList<Statement*>* stmts) {
-  // Visit statements right-to-left.
-  for (int i = stmts->length() - 1; i >= 0; i--) {
-    Visit(stmts->at(i));
-  }
-}
-
-
-void LivenessAnalyzer::RecordUse(Variable* var, Expression* expr) {
-  ASSERT(var->is_global() || var->is_this());
-  ZoneList<Expression*>* uses = live_vars_.Lookup(var);
-  uses->Add(expr);
-}
-
-
-void LivenessAnalyzer::RecordDef(Variable* var, Expression* expr) {
-  ASSERT(var->is_global() || var->is_this());
-
-  // We do not support other expressions that can define variables.
-  ASSERT(expr->AsFunctionLiteral() != NULL);
-
-  // Add the variable to the list of defined variables.
-  if (expr->defined_vars() == NULL) {
-    expr->set_defined_vars(new ZoneList<DefinitionInfo*>(1));
-  }
-  DefinitionInfo* def = new DefinitionInfo();
-  expr->AsFunctionLiteral()->defined_vars()->Add(def);
-
-  // Compute the last use of the definition. The variable uses are
-  // inserted in reversed evaluation order. The first element
-  // in the list of live uses is the last use.
-  ZoneList<Expression*>* uses = live_vars_.Lookup(var);
-  while (uses->length() > 0) {
-    Expression* use_site = uses->RemoveLast();
-    use_site->set_var_def(def);
-    if (uses->length() == 0) {
-      def->set_last_use(use_site);
-    }
-  }
-}
-
-
-// Visitor functions for live variable analysis.
-void LivenessAnalyzer::VisitDeclaration(Declaration* decl) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitBlock(Block* stmt) {
-  VisitStatements(stmt->statements());
-}
-
-
-void LivenessAnalyzer::VisitExpressionStatement(
-    ExpressionStatement* stmt) {
-  Visit(stmt->expression());
-}
-
-
-void LivenessAnalyzer::VisitEmptyStatement(EmptyStatement* stmt) {
-  // Do nothing.
-}
-
-
-void LivenessAnalyzer::VisitIfStatement(IfStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitContinueStatement(ContinueStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitBreakStatement(BreakStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitReturnStatement(ReturnStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitWithEnterStatement(
-    WithEnterStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitWithExitStatement(WithExitStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitSwitchStatement(SwitchStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitDoWhileStatement(DoWhileStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitWhileStatement(WhileStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitForStatement(ForStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitForInStatement(ForInStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitTryCatchStatement(TryCatchStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitTryFinallyStatement(
-    TryFinallyStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitDebuggerStatement(
-    DebuggerStatement* stmt) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitFunctionLiteral(FunctionLiteral* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitFunctionBoilerplateLiteral(
-    FunctionBoilerplateLiteral* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitConditional(Conditional* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitSlot(Slot* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitVariableProxy(VariableProxy* expr) {
-  Variable* var = expr->var();
-  ASSERT(var->is_global());
-  ASSERT(!var->is_this());
-  RecordUse(var, expr);
-}
-
-
-void LivenessAnalyzer::VisitLiteral(Literal* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitRegExpLiteral(RegExpLiteral* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitObjectLiteral(ObjectLiteral* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitArrayLiteral(ArrayLiteral* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitCatchExtensionObject(
-    CatchExtensionObject* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitAssignment(Assignment* expr) {
-  Property* prop = expr->target()->AsProperty();
-  ASSERT(prop != NULL);
-  ASSERT(prop->key()->IsPropertyName());
-  VariableProxy* proxy = prop->obj()->AsVariableProxy();
-  ASSERT(proxy != NULL && proxy->var()->is_this());
-
-  // Record use of this at the assignment node. Assignments to
-  // this-properties are treated like unary operations.
-  RecordUse(proxy->var(), expr);
-
-  // Visit right-hand side.
-  Visit(expr->value());
-}
-
-
-void LivenessAnalyzer::VisitThrow(Throw* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitProperty(Property* expr) {
-  ASSERT(expr->key()->IsPropertyName());
-  VariableProxy* proxy = expr->obj()->AsVariableProxy();
-  ASSERT(proxy != NULL && proxy->var()->is_this());
-  RecordUse(proxy->var(), expr);
-}
-
-
-void LivenessAnalyzer::VisitCall(Call* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitCallNew(CallNew* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitCallRuntime(CallRuntime* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitUnaryOperation(UnaryOperation* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitCountOperation(CountOperation* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitBinaryOperation(BinaryOperation* expr) {
-  // Visit child nodes in reverse evaluation order.
-  Visit(expr->right());
-  Visit(expr->left());
-}
-
-
-void LivenessAnalyzer::VisitCompareOperation(CompareOperation* expr) {
-  UNREACHABLE();
-}
-
-
-void LivenessAnalyzer::VisitThisFunction(ThisFunction* expr) {
-  UNREACHABLE();
-}
-
-
 AssignedVariablesAnalyzer::AssignedVariablesAnalyzer(FunctionLiteral* fun)
     : fun_(fun),
       av_(fun->scope()->num_parameters() + fun->scope()->num_stack_slots()) {}

src/data-flow.h

@@ -550,55 +550,6 @@ class AstLabeler: public AstVisitor {
 };
 
 
-class VarUseMap : public HashMap {
- public:
-  VarUseMap() : HashMap(VarMatch) {}
-
-  ZoneList<Expression*>* Lookup(Variable* var);
-
- private:
-  static bool VarMatch(void* key1, void* key2) { return key1 == key2; }
-};
-
-
-class DefinitionInfo : public ZoneObject {
- public:
-  explicit DefinitionInfo() : last_use_(NULL) {}
-
-  Expression* last_use() { return last_use_; }
-  void set_last_use(Expression* expr) { last_use_ = expr; }
-
- private:
-  Expression* last_use_;
-  Register location_;
-};
-
-
-class LivenessAnalyzer : public AstVisitor {
- public:
-  LivenessAnalyzer() {}
-
-  void Analyze(FunctionLiteral* fun);
-
- private:
-  void VisitStatements(ZoneList<Statement*>* stmts);
-
-  void RecordUse(Variable* var, Expression* expr);
-  void RecordDef(Variable* var, Expression* expr);
-
-
-  // AST node visit functions.
-#define DECLARE_VISIT(type) virtual void Visit##type(type* node);
-  AST_NODE_LIST(DECLARE_VISIT)
-#undef DECLARE_VISIT
-
-  // Map for tracking the live variables.
-  VarUseMap live_vars_;
-
-  DISALLOW_COPY_AND_ASSIGN(LivenessAnalyzer);
-};
-
-
 // Computes the set of assigned variables and annotates variables proxies
 // that are trivial sub-expressions and for-loops where the loop variable
 // is guaranteed to be a smi.

src/fast-codegen.cc

@@ -436,9 +436,6 @@ Handle<Code> FastCodeGenerator::MakeCode(CompilationInfo* info) {
   AstLabeler labeler;
   labeler.Label(info);
 
-  LivenessAnalyzer analyzer;
-  analyzer.Analyze(info->function());
-
   CodeGenerator::MakeCodePrologue(info);
 
   const int kInitialBufferSize = 4 * KB;
@@ -598,8 +595,8 @@ void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
     Comment cmnt(masm(), ";; Global");
     if (FLAG_print_ir) {
       SmartPointer<char> name = expr->name()->ToCString();
-      PrintF("%d: t%d = Global(%s)  // last_use = %d\n", expr->num(),
-             expr->num(), *name, expr->var_def()->last_use()->num());
+      PrintF("%d: t%d = Global(%s)\n", expr->num(),
+             expr->num(), *name);
     }
     EmitGlobalVariableLoad(cell);
   }
@@ -653,9 +650,8 @@ void FastCodeGenerator::VisitAssignment(Assignment* expr) {
     SmartPointer<char> name_string = name->ToCString();
     PrintF("%d: ", expr->num());
     if (!destination().is(no_reg)) PrintF("t%d = ", expr->num());
-    PrintF("Store(this, \"%s\", t%d)  // last_use(this) = %d\n", *name_string,
-           expr->value()->num(),
-           expr->var_def()->last_use()->num());
+    PrintF("Store(this, \"%s\", t%d)\n", *name_string,
+           expr->value()->num());
   }
 
   EmitThisPropertyStore(name);
@@ -678,9 +674,8 @@ void FastCodeGenerator::VisitProperty(Property* expr) {
     Comment cmnt(masm(), ";; Load from this");
     if (FLAG_print_ir) {
       SmartPointer<char> name_string = name->ToCString();
-      PrintF("%d: t%d = Load(this, \"%s\")  // last_use(this) = %d\n",
-             expr->num(), expr->num(), *name_string,
-             expr->var_def()->last_use()->num());
+      PrintF("%d: t%d = Load(this, \"%s\")\n",
+             expr->num(), expr->num(), *name_string);
     }
     EmitThisPropertyLoad(name);
   }

src/ia32/fast-codegen-ia32.cc

@@ -436,9 +436,6 @@ Handle<Code> FastCodeGenerator::MakeCode(CompilationInfo* info) {
   AstLabeler labeler;
   labeler.Label(info);
 
-  LivenessAnalyzer analyzer;
-  analyzer.Analyze(info->function());
-
   CodeGenerator::MakeCodePrologue(info);
 
   const int kInitialBufferSize = 4 * KB;
@@ -802,8 +799,8 @@ void FastCodeGenerator::VisitVariableProxy(VariableProxy* expr) {
     Comment cmnt(masm(), ";; Global");
     if (FLAG_print_ir) {
       SmartPointer<char> name = expr->name()->ToCString();
-      PrintF("%d: t%d = Global(%s)  // last_use = %d\n", expr->num(),
-             expr->num(), *name, expr->var_def()->last_use()->num());
+      PrintF("%d: t%d = Global(%s)\n", expr->num(),
+             expr->num(), *name);
     }
     EmitGlobalVariableLoad(cell);
   }
@@ -857,9 +854,8 @@ void FastCodeGenerator::VisitAssignment(Assignment* expr) {
     SmartPointer<char> name_string = name->ToCString();
     PrintF("%d: ", expr->num());
     if (!destination().is(no_reg)) PrintF("t%d = ", expr->num());
-    PrintF("Store(this, \"%s\", t%d)  // last_use(this) = %d\n", *name_string,
-           expr->value()->num(),
-           expr->var_def()->last_use()->num());
+    PrintF("Store(this, \"%s\", t%d)\n", *name_string,
+           expr->value()->num());
   }
 
   EmitThisPropertyStore(name);
@@ -882,9 +878,8 @@ void FastCodeGenerator::VisitProperty(Property* expr) {
     Comment cmnt(masm(), ";; Load from this");
     if (FLAG_print_ir) {
       SmartPointer<char> name_string = name->ToCString();
-      PrintF("%d: t%d = Load(this, \"%s\")  // last_use(this) = %d\n",
-             expr->num(), expr->num(), *name_string,
-             expr->var_def()->last_use()->num());
+      PrintF("%d: t%d = Load(this, \"%s\")\n",
+             expr->num(), expr->num(), *name_string);
     }
     EmitThisPropertyLoad(name);
   }