Remove unused AssignedVariableAnalyzer.

src/data-flow.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 45 matching lines @@
     current_index_++;
     if (Done()) return;
     val = target_->data_[current_index_];
     current_ = current_index_ << 5;
   }
   val = SkipZeroBytes(val);
   val = SkipZeroBits(val);
   current_value_ = val >> 1;
 }
 
-
-bool AssignedVariablesAnalyzer::Analyze(CompilationInfo* info) {
-  Scope* scope = info->scope();
-  int size = scope->num_parameters() + scope->num_stack_slots();
-  if (size == 0) return true;
-  AssignedVariablesAnalyzer analyzer(info, size);
-  return analyzer.Analyze();
-}
-
-
-AssignedVariablesAnalyzer::AssignedVariablesAnalyzer(CompilationInfo* info,
-                                                     int size)
-    : info_(info), av_(size) {
-}
-
-
-bool AssignedVariablesAnalyzer::Analyze() {
-  ASSERT(av_.length() > 0);
-  VisitStatements(info_->function()->body());
-  return !HasStackOverflow();
-}
-
-
-Variable* AssignedVariablesAnalyzer::FindSmiLoopVariable(ForStatement* stmt) {
-  // The loop must have all necessary parts.
-  if (stmt->init() == NULL || stmt->cond() == NULL || stmt->next() == NULL) {
-    return NULL;
-  }
-  // The initialization statement has to be a simple assignment.
-  Assignment* init = stmt->init()->StatementAsSimpleAssignment();
-  if (init == NULL) return NULL;
-
-  // We only deal with local variables.
-  Variable* loop_var = init->target()->AsVariableProxy()->AsVariable();
-  if (loop_var == NULL || !loop_var->IsStackAllocated()) return NULL;
-
-  // Don't try to get clever with const or dynamic variables.
-  if (loop_var->mode() != Variable::VAR) return NULL;
-
-  // The initial value has to be a smi.
-  Literal* init_lit = init->value()->AsLiteral();
-  if (init_lit == NULL || !init_lit->handle()->IsSmi()) return NULL;
-  int init_value = Smi::cast(*init_lit->handle())->value();
-
-  // The condition must be a compare of variable with <, <=, >, or >=.
-  CompareOperation* cond = stmt->cond()->AsCompareOperation();
-  if (cond == NULL) return NULL;
-  if (cond->op() != Token::LT
-      && cond->op() != Token::LTE
-      && cond->op() != Token::GT
-      && cond->op() != Token::GTE) return NULL;
-
-  // The lhs must be the same variable as in the init expression.
-  if (cond->left()->AsVariableProxy()->AsVariable() != loop_var) return NULL;
-
-  // The rhs must be a smi.
-  Literal* term_lit = cond->right()->AsLiteral();
-  if (term_lit == NULL || !term_lit->handle()->IsSmi()) return NULL;
-  int term_value = Smi::cast(*term_lit->handle())->value();
-
-  // The count operation updates the same variable as in the init expression.
-  CountOperation* update = stmt->next()->StatementAsCountOperation();
-  if (update == NULL) return NULL;
-  if (update->expression()->AsVariableProxy()->AsVariable() != loop_var) {
-    return NULL;
-  }
-
-  // The direction of the count operation must agree with the start and the end
-  // value. We currently do not allow the initial value to be the same as the
-  // terminal value. This _would_ be ok as long as the loop body never executes
-  // or executes exactly one time.
-  if (init_value == term_value) return NULL;
-  if (init_value < term_value && update->op() != Token::INC) return NULL;
-  if (init_value > term_value && update->op() != Token::DEC) return NULL;
-
-  // Check that the update operation cannot overflow the smi range. This can
-  // occur in the two cases where the loop bound is equal to the largest or
-  // smallest smi.
-  if (update->op() == Token::INC && term_value == Smi::kMaxValue) return NULL;
-  if (update->op() == Token::DEC && term_value == Smi::kMinValue) return NULL;
-
-  // Found a smi loop variable.
-  return loop_var;
-}
-
-int AssignedVariablesAnalyzer::BitIndex(Variable* var) {
-  ASSERT(var != NULL);
-  ASSERT(var->IsStackAllocated());
-  Slot* slot = var->AsSlot();
-  if (slot->type() == Slot::PARAMETER) {
-    return slot->index();
-  } else {
-    return info_->scope()->num_parameters() + slot->index();
-  }
-}
-
-
-void AssignedVariablesAnalyzer::RecordAssignedVar(Variable* var) {
-  ASSERT(var != NULL);
-  if (var->IsStackAllocated()) {
-    av_.Add(BitIndex(var));
-  }
-}
-
-
-void AssignedVariablesAnalyzer::MarkIfTrivial(Expression* expr) {
-  Variable* var = expr->AsVariableProxy()->AsVariable();
-  if (var != NULL &&
-      var->IsStackAllocated() &&
-      !var->is_arguments() &&
-      var->mode() != Variable::CONST &&
-      (var->is_this() || !av_.Contains(BitIndex(var)))) {
-    expr->AsVariableProxy()->MarkAsTrivial();
-  }
-}
-
-
-void AssignedVariablesAnalyzer::ProcessExpression(Expression* expr) {
-  BitVector saved_av(av_);
-  av_.Clear();
-  Visit(expr);
-  av_.Union(saved_av);
-}
-
-void AssignedVariablesAnalyzer::VisitBlock(Block* stmt) {
-  VisitStatements(stmt->statements());
-}
-
-
-void AssignedVariablesAnalyzer::VisitExpressionStatement(
-    ExpressionStatement* stmt) {
-  ProcessExpression(stmt->expression());
-}
-
-
-void AssignedVariablesAnalyzer::VisitEmptyStatement(EmptyStatement* stmt) {
-  // Do nothing.
-}
-
-
-void AssignedVariablesAnalyzer::VisitIfStatement(IfStatement* stmt) {
-  ProcessExpression(stmt->condition());
-  Visit(stmt->then_statement());
-  Visit(stmt->else_statement());
-}
-
-
-void AssignedVariablesAnalyzer::VisitContinueStatement(
-    ContinueStatement* stmt) {
-  // Nothing to do.
-}
-
-
-void AssignedVariablesAnalyzer::VisitBreakStatement(BreakStatement* stmt) {
-  // Nothing to do.
-}
-
-
-void AssignedVariablesAnalyzer::VisitReturnStatement(ReturnStatement* stmt) {
-  ProcessExpression(stmt->expression());
-}
-
-
-void AssignedVariablesAnalyzer::VisitWithEnterStatement(
-    WithEnterStatement* stmt) {
-  ProcessExpression(stmt->expression());
-}
-
-
-void AssignedVariablesAnalyzer::VisitWithExitStatement(
-    WithExitStatement* stmt) {
-  // Nothing to do.
-}
-
-
-void AssignedVariablesAnalyzer::VisitSwitchStatement(SwitchStatement* stmt) {
-  BitVector result(av_);
-  av_.Clear();
-  Visit(stmt->tag());
-  result.Union(av_);
-  for (int i = 0; i < stmt->cases()->length(); i++) {
-    CaseClause* clause = stmt->cases()->at(i);
-    if (!clause->is_default()) {
-      av_.Clear();
-      Visit(clause->label());
-      result.Union(av_);
-    }
-    VisitStatements(clause->statements());
-  }
-  av_.Union(result);
-}
-
-
-void AssignedVariablesAnalyzer::VisitDoWhileStatement(DoWhileStatement* stmt) {
-  ProcessExpression(stmt->cond());
-  Visit(stmt->body());
-}
-
-
-void AssignedVariablesAnalyzer::VisitWhileStatement(WhileStatement* stmt) {
-  ProcessExpression(stmt->cond());
-  Visit(stmt->body());
-}
-
-
-void AssignedVariablesAnalyzer::VisitForStatement(ForStatement* stmt) {
-  if (stmt->init() != NULL) Visit(stmt->init());
-  if (stmt->cond() != NULL) ProcessExpression(stmt->cond());
-  if (stmt->next() != NULL) Visit(stmt->next());
-
-  // Process loop body. After visiting the loop body av_ contains
-  // the assigned variables of the loop body.
-  BitVector saved_av(av_);
-  av_.Clear();
-  Visit(stmt->body());
-
-  Variable* var = FindSmiLoopVariable(stmt);
-  if (var != NULL && !av_.Contains(BitIndex(var))) {
-    stmt->set_loop_variable(var);
-  }
-  av_.Union(saved_av);
-}
-
-
-void AssignedVariablesAnalyzer::VisitForInStatement(ForInStatement* stmt) {
-  ProcessExpression(stmt->each());
-  ProcessExpression(stmt->enumerable());
-  Visit(stmt->body());
-}
-
-
-void AssignedVariablesAnalyzer::VisitTryCatchStatement(
-    TryCatchStatement* stmt) {
-  Visit(stmt->try_block());
-  Visit(stmt->catch_block());
-}
-
-
-void AssignedVariablesAnalyzer::VisitTryFinallyStatement(
-    TryFinallyStatement* stmt) {
-  Visit(stmt->try_block());
-  Visit(stmt->finally_block());
-}
-
-
-void AssignedVariablesAnalyzer::VisitDebuggerStatement(
-    DebuggerStatement* stmt) {
-  // Nothing to do.
-}
-
-
-void AssignedVariablesAnalyzer::VisitFunctionLiteral(FunctionLiteral* expr) {
-  // Nothing to do.
-  ASSERT(av_.IsEmpty());
-}
-
-
-void AssignedVariablesAnalyzer::VisitSharedFunctionInfoLiteral(
-    SharedFunctionInfoLiteral* expr) {
-  // Nothing to do.
-  ASSERT(av_.IsEmpty());
-}
-
-
-void AssignedVariablesAnalyzer::VisitConditional(Conditional* expr) {
-  ASSERT(av_.IsEmpty());
-
-  Visit(expr->condition());
-
-  BitVector result(av_);
-  av_.Clear();
-  Visit(expr->then_expression());
-  result.Union(av_);
-
-  av_.Clear();
-  Visit(expr->else_expression());
-  av_.Union(result);
-}
-
-
-void AssignedVariablesAnalyzer::VisitVariableProxy(VariableProxy* expr) {
-  // Nothing to do.
-  ASSERT(av_.IsEmpty());
-}
-
-
-void AssignedVariablesAnalyzer::VisitLiteral(Literal* expr) {
-  // Nothing to do.
-  ASSERT(av_.IsEmpty());
-}
-
-
-void AssignedVariablesAnalyzer::VisitRegExpLiteral(RegExpLiteral* expr) {
-  // Nothing to do.
-  ASSERT(av_.IsEmpty());
-}
-
-
-void AssignedVariablesAnalyzer::VisitObjectLiteral(ObjectLiteral* expr) {
-  ASSERT(av_.IsEmpty());
-  BitVector result(av_.length());
-  for (int i = 0; i < expr->properties()->length(); i++) {
-    Visit(expr->properties()->at(i)->value());
-    result.Union(av_);
-    av_.Clear();
-  }
-  av_ = result;
-}
-
-
-void AssignedVariablesAnalyzer::VisitArrayLiteral(ArrayLiteral* expr) {
-  ASSERT(av_.IsEmpty());
-  BitVector result(av_.length());
-  for (int i = 0; i < expr->values()->length(); i++) {
-    Visit(expr->values()->at(i));
-    result.Union(av_);
-    av_.Clear();
-  }
-  av_ = result;
-}
-
-
-void AssignedVariablesAnalyzer::VisitCatchExtensionObject(
-    CatchExtensionObject* expr) {
-  ASSERT(av_.IsEmpty());
-  Visit(expr->key());
-  ProcessExpression(expr->value());
-}
-
-
-void AssignedVariablesAnalyzer::VisitAssignment(Assignment* expr) {
-  ASSERT(av_.IsEmpty());
-
-  // There are three kinds of assignments: variable assignments, property
-  // assignments, and reference errors (invalid left-hand sides).
-  Variable* var = expr->target()->AsVariableProxy()->AsVariable();
-  Property* prop = expr->target()->AsProperty();
-  ASSERT(var == NULL || prop == NULL);
-
-  if (var != NULL) {
-    MarkIfTrivial(expr->value());
-    Visit(expr->value());
-    if (expr->is_compound()) {
-      // Left-hand side occurs also as an rvalue.
-      MarkIfTrivial(expr->target());
-      ProcessExpression(expr->target());
-    }
-    RecordAssignedVar(var);
-
-  } else if (prop != NULL) {
-    MarkIfTrivial(expr->value());
-    Visit(expr->value());
-    if (!prop->key()->IsPropertyName()) {
-      MarkIfTrivial(prop->key());
-      ProcessExpression(prop->key());
-    }
-    MarkIfTrivial(prop->obj());
-    ProcessExpression(prop->obj());
-
-  } else {
-    Visit(expr->target());
-  }
-}
-
-
-void AssignedVariablesAnalyzer::VisitThrow(Throw* expr) {
-  ASSERT(av_.IsEmpty());
-  Visit(expr->exception());
-}
-
-
-void AssignedVariablesAnalyzer::VisitProperty(Property* expr) {
-  ASSERT(av_.IsEmpty());
-  if (!expr->key()->IsPropertyName()) {
-    MarkIfTrivial(expr->key());
-    Visit(expr->key());
-  }
-  MarkIfTrivial(expr->obj());
-  ProcessExpression(expr->obj());
-}
-
-
-void AssignedVariablesAnalyzer::VisitCall(Call* expr) {
-  ASSERT(av_.IsEmpty());
-  Visit(expr->expression());
-  BitVector result(av_);
-  for (int i = 0; i < expr->arguments()->length(); i++) {
-    av_.Clear();
-    Visit(expr->arguments()->at(i));
-    result.Union(av_);
-  }
-  av_ = result;
-}
-
-
-void AssignedVariablesAnalyzer::VisitCallNew(CallNew* expr) {
-  ASSERT(av_.IsEmpty());
-  Visit(expr->expression());
-  BitVector result(av_);
-  for (int i = 0; i < expr->arguments()->length(); i++) {
-    av_.Clear();
-    Visit(expr->arguments()->at(i));
-    result.Union(av_);
-  }
-  av_ = result;
-}
-
-
-void AssignedVariablesAnalyzer::VisitCallRuntime(CallRuntime* expr) {
-  ASSERT(av_.IsEmpty());
-  BitVector result(av_);
-  for (int i = 0; i < expr->arguments()->length(); i++) {
-    av_.Clear();
-    Visit(expr->arguments()->at(i));
-    result.Union(av_);
-  }
-  av_ = result;
-}
-
-
-void AssignedVariablesAnalyzer::VisitUnaryOperation(UnaryOperation* expr) {
-  ASSERT(av_.IsEmpty());
-  MarkIfTrivial(expr->expression());
-  Visit(expr->expression());
-}
-
-
-void AssignedVariablesAnalyzer::VisitCountOperation(CountOperation* expr) {
-  ASSERT(av_.IsEmpty());
-  if (expr->is_prefix()) MarkIfTrivial(expr->expression());
-  Visit(expr->expression());
-
-  Variable* var = expr->expression()->AsVariableProxy()->AsVariable();
-  if (var != NULL) RecordAssignedVar(var);
-}
-
-
-void AssignedVariablesAnalyzer::VisitBinaryOperation(BinaryOperation* expr) {
-  ASSERT(av_.IsEmpty());
-  MarkIfTrivial(expr->right());
-  Visit(expr->right());
-  MarkIfTrivial(expr->left());
-  ProcessExpression(expr->left());
-}
-
-
-void AssignedVariablesAnalyzer::VisitCompareOperation(CompareOperation* expr) {
-  ASSERT(av_.IsEmpty());
-  MarkIfTrivial(expr->right());
-  Visit(expr->right());
-  MarkIfTrivial(expr->left());
-  ProcessExpression(expr->left());
-}
-
-
-void AssignedVariablesAnalyzer::VisitCompareToNull(CompareToNull* expr) {
-  ASSERT(av_.IsEmpty());
-  MarkIfTrivial(expr->expression());
-  Visit(expr->expression());
-}
-
-
-void AssignedVariablesAnalyzer::VisitThisFunction(ThisFunction* expr) {
-  // Nothing to do.
-  ASSERT(av_.IsEmpty());
-}
-
-
-void AssignedVariablesAnalyzer::VisitDeclaration(Declaration* decl) {
-  UNREACHABLE();
-}
-
-
 } }  // namespace v8::internal