ExpressionPtr BinaryOpExpression::simplifyLogical(AnalysisResultPtr ar) {
if (m_exp1->is(Expression::KindOfConstantExpression)) {
ConstantExpressionPtr con =
dynamic_pointer_cast<ConstantExpression>(m_exp1);
if (con->isBoolean()) {
if (con->getBooleanValue()) {
if (ar->getPhase() >= AnalysisResult::PostOptimize) {
// true && v (true AND v) => v
ASSERT(m_exp2->getType()->is(Type::KindOfBoolean));
if (m_op == T_BOOLEAN_AND || m_op == T_LOGICAL_AND) return m_exp2;
}
// true || v (true OR v) => true
if (m_op == T_BOOLEAN_OR || m_op == T_LOGICAL_OR) {
return CONSTANT("true");
}
} else {
if (ar->getPhase() >= AnalysisResult::PostOptimize) {
ASSERT(m_exp2->getType()->is(Type::KindOfBoolean));
// false || v (false OR v) => v
if (m_op == T_BOOLEAN_OR || m_op == T_LOGICAL_OR) return m_exp2;
}
// false && v (false AND v) => false
if (m_op == T_BOOLEAN_AND || m_op == T_LOGICAL_AND) {
return CONSTANT("false");
}
}
}
}
if (m_exp2->is(Expression::KindOfConstantExpression)) {
ConstantExpressionPtr con =
dynamic_pointer_cast<ConstantExpression>(m_exp2);
if (con->isBoolean()) {
if (con->getBooleanValue()) {
if (ar->getPhase() >= AnalysisResult::PostOptimize) {
ASSERT(m_exp1->getType()->is(Type::KindOfBoolean));
// v && true (v AND true) => v
if (m_op == T_BOOLEAN_AND || m_op == T_LOGICAL_AND) return m_exp1;
}
// v || true (v OR true) => true when v does not have effect
if (m_op == T_BOOLEAN_OR || m_op == T_LOGICAL_OR) {
if (!m_exp1->hasEffect()) return CONSTANT("true");
}
} else {
if (ar->getPhase() >= AnalysisResult::PostOptimize) {
ASSERT(m_exp1->getType()->is(Type::KindOfBoolean));
// v || false (v OR false) => v
if (m_op == T_BOOLEAN_OR || m_op == T_LOGICAL_OR) return m_exp1;
}
// v && false (v AND false) => false when v does not have effect
if (m_op == T_BOOLEAN_AND || m_op == T_LOGICAL_AND) {
if (!m_exp1->hasEffect()) return CONSTANT("false");
}
}
}
}
return ExpressionPtr();
}
bool Option::Load(bool &option, ExpressionPtr value) {
ConstantExpressionPtr v = dynamic_pointer_cast<ConstantExpression>(value);
if (!v || !v->isBoolean()) {
Logger::Error("Line %d: invalid boolean: %s", value->getLocation()->line1,
value->getText().c_str());
return false;
}
option = v->getBooleanValue();
return true;
}
StatementPtr IfStatement::postOptimize(AnalysisResultConstPtr ar) {
// we cannot optimize away the code inside if statement, because
// there may be a goto that goes into if statement.
if (hasReachableLabel()) {
return StatementPtr();
}
bool changed = false;
for (int i = 0; i < m_stmts->getCount(); i++) {
IfBranchStatementPtr branch =
dynamic_pointer_cast<IfBranchStatement>((*m_stmts)[i]);
ExpressionPtr condition = branch->getCondition();
if (!branch->getStmt() || !branch->getStmt()->hasImpl()) {
if (!condition ||
(i == m_stmts->getCount() - 1 &&
!condition->hasEffect())) {
// remove else branch without C++ implementation.
m_stmts->removeElement(i);
changed = true;
} else if (condition->is(Expression::KindOfConstantExpression)) {
ConstantExpressionPtr exp =
dynamic_pointer_cast<ConstantExpression>(condition);
// Remove if (false) branch without C++ implementation.
// if (true) branch without C++ implementation is kept unless
// it is the last branch. In general we cannot let a if (true)
// branch short-circuit the rest branches which if removed may
// cause g++ to complain unreferenced variables.
if (exp->isBoolean()) {
if (!exp->getBooleanValue() ||
(exp->getBooleanValue() && i == m_stmts->getCount() - 1)) {
m_stmts->removeElement(i);
changed = true;
i--;
}
}
}
}
}
if (m_stmts->getCount() == 0) {
return NULL_STATEMENT();
} else {
return changed ? static_pointer_cast<Statement>(shared_from_this())
: StatementPtr();
}
}
StatementPtr IfStatement::preOptimize(AnalysisResultPtr ar) {
if (ar->getPhase() < AnalysisResult::FirstPreOptimize) {
return StatementPtr();
}
bool changed = false;
int i;
int j;
for (i = 0; i < m_stmts->getCount(); i++) {
IfBranchStatementPtr branch =
dynamic_pointer_cast<IfBranchStatement>((*m_stmts)[i]);
ExpressionPtr condition = branch->getCondition();
if (!condition) {
StatementPtr stmt = branch->getStmt();
if (stmt && stmt->is(KindOfIfStatement)) {
StatementListPtr sub_stmts =
dynamic_pointer_cast<IfStatement>(stmt)->m_stmts;
m_stmts->removeElement(i);
changed = true;
for (j = 0; j < sub_stmts->getCount(); j++) {
m_stmts->insertElement((*sub_stmts)[j], i++);
}
}
break;
} else if (condition->is(Expression::KindOfConstantExpression)) {
ConstantExpressionPtr exp =
dynamic_pointer_cast<ConstantExpression>(condition);
if (exp->isBoolean()) {
if (exp->getBooleanValue()) {
// if (true) branch
for (j = i + 1; j < m_stmts->getCount(); j++) {
if ((*m_stmts)[j]->hasDecl()) break;
}
// no declarations after if (true)
if (j == m_stmts->getCount()) break;
} else {
// if (false) branch
if (!branch->hasDecl()) {
m_stmts->removeElement(i);
changed = true;
i--;
}
}
}
}
}
if (i == m_stmts->getCount()) return StatementPtr();
// either else branch or if (true) branch without further declarations
i++;
while (i < m_stmts->getCount()) {
m_stmts->removeElement(i);
changed = true;
}
// if there is only one branch left, return stmt.
if (m_stmts->getCount() == 1) {
return dynamic_pointer_cast<IfBranchStatement>((*m_stmts)[0])->getStmt();
} else if (m_stmts->getCount() == 0) {
return NULL_STATEMENT();
} else {
return changed ? static_pointer_cast<Statement>(shared_from_this())
: StatementPtr();
}
}
