CTacAddr* CAstStatIf::ToTac(CCodeBlock *cb, CTacLabel *next)
{
CTacLabel* truelabel = cb->CreateLabel("if_true"); // true label
CTacLabel* falselabel = cb->CreateLabel("if_false"); // false label
_cond->ToTac(cb, truelabel, falselabel); // calculate condition
CAstStatement *s = _ifBody;
cb->AddInstr(truelabel); // install true label
while(s != NULL) { // TAC of ifBody
CTacLabel* tempnext = cb->CreateLabel();
s->ToTac(cb, tempnext);
cb->AddInstr(tempnext);
s = s->GetNext();
}
cb->AddInstr(new CTacInstr(opGoto, next)); // skip to next
s = _elseBody;
cb->AddInstr(falselabel); // install false label
while(s != NULL) { // TAC of elseBody
CTacLabel* tempnext = cb->CreateLabel();
s->ToTac(cb, tempnext);
cb->AddInstr(tempnext);
s = s->GetNext();
}
cb->AddInstr(new CTacInstr(opGoto, next)); // goto next
return NULL;
}
void CAstScope::toDot(ostream &out, int indent) const
{
string ind(indent, ' ');
CAstNode::toDot(out, indent);
CAstStatement *s = GetStatementSequence();
if (s != NULL) {
string prev = dotID();
do {
s->toDot(out, indent);
out << ind << prev << " -> " << s->dotID() << " [style=dotted];" << endl;
prev = s->dotID();
s = s->GetNext();
} while (s != NULL);
}
vector<CAstScope*>::const_iterator it = _children.begin();
while (it != _children.end()) {
CAstScope *s = *it++;
s->toDot(out, indent);
out << ind << dotID() << " -> " << s->dotID() << ";" << endl;
}
}
CTacAddr* CAstStatWhile::ToTac(CCodeBlock *cb, CTacLabel *next)
{
assert(cb != NULL && next != NULL);
CAstExpression *cond = GetCondition();
CAstStatement *body = GetBody();
CTacLabel *while_cond = cb->CreateLabel("while_cond");
CTacLabel *c_true = cb->CreateLabel("while_body");
// while condition begins
cb->AddInstr(while_cond);
CTacAddr *tCond = cond->ToTac(cb, c_true, next);
if(dynamic_cast<CAstDesignator*>(cond)) { // if cond is a single boolean
cb->AddInstr(new CTacInstr(opEqual, c_true, tCond, new CTacConst(1)));
cb->AddInstr(new CTacInstr(opGoto, next));
}
// while body starts..
cb->AddInstr(c_true);
while(body) {
CTacLabel *while_next = cb->CreateLabel("while_next");
body->ToTac(cb, while_next);
cb->AddInstr(while_next);
body = body->GetNext();
}
cb->AddInstr(new CTacInstr(opGoto, while_cond));
return NULL;
}
ostream& CAstScope::print(ostream &out, int indent) const
{
string ind(indent, ' ');
out << ind << "CAstScope: '" << _name << "'" << endl;
out << ind << " symbol table:" << endl;
_symtab->print(out, indent+4);
out << ind << " statement list:" << endl;
CAstStatement *s = GetStatementSequence();
if (s != NULL) {
do {
s->print(out, indent+4);
s = s->GetNext();
} while (s != NULL);
} else {
out << ind << " empty." << endl;
}
out << ind << " nested scopes:" << endl;
if (_children.size() > 0) {
for (size_t i=0; i<_children.size(); i++) {
_children[i]->print(out, indent+4);
}
} else {
out << ind << " empty." << endl;
}
out << ind << endl;
return out;
}
CTacAddr* CAstScope::ToTac(CCodeBlock *cb)
{
assert (cb != NULL);
CAstStatement *s = GetStatementSequence();
while(s != NULL) { // statements -> TAC. connect each by "next" label
CTacLabel *next = cb->CreateLabel();
s->ToTac(cb, next);
cb->AddInstr(next);
s = s->GetNext();
}
cb->CleanupControlFlow(); // clean up control flow
return NULL;
}
CAstStatement* CParser::statSequence(CAstScope *s) {
//
// statSequence ::= [ statement { ";" statement } ].
// FIRST(statement) = {tIF, tWhile, tReturn, tIdent}.
// FOLLOW(statSequence) = {tEnd, tElse}.
//
CAstStatement *head = NULL;
CAstStatement *tail = NULL;
EToken tt = _scanner->Peek().GetType();
switch(tt) {
case tIf:
case tWhile:
case tReturn:
case tIdent:
head = tail = statement(s);
assert(head != NULL);
// for multiple statements.
while(1) {
if(_scanner->Peek().GetType() == tEnd ||
_scanner->Peek().GetType() == tElse) {
break;
}
else {
Consume(tSemicolon);
CAstStatement *st = NULL;
st = statement(s);
assert(st != NULL);
tail->SetNext(st);
tail = st;
}
}
break;
default:
break;
}
return head;
}
bool CAstStatWhile::TypeCheck(CToken *t, string *msg) const
{
if(!_cond->TypeCheck(t, msg)) return false; // Do TypeCheck on condition expression
if(!_cond->GetType()->IsBoolean()) {
if(t != NULL) *t = _cond->GetToken();
if(msg != NULL) *msg = "boolean expression expected.";
return false;
}
bool result = true;
CAstStatement *s = _body;
while(result && (s != NULL)) { // Do TypeCheck on all body-statements
result = s->TypeCheck(t, msg);
s = s->GetNext();
}
return result;
}
CTacAddr* CAstScope::ToTac(CCodeBlock *cb)
{
assert(cb != NULL);
CAstStatement *s = GetStatementSequence();
// ToTac for all statement sequence.
while (s != NULL) {
CTacLabel *next = cb->CreateLabel();
s->ToTac(cb, next);
cb->AddInstr(next);
s = s->GetNext();
}
// clean up all unnecessary labels.
cb->CleanupControlFlow();
return NULL;
}
ostream& CAstStatWhile::print(ostream &out, int indent) const
{
string ind(indent, ' ');
out << ind << "while cond" << endl;
_cond->print(out, indent+2);
out << ind << "while-body" << endl;
if (_body != NULL) {
CAstStatement *s = _body;
do {
s->print(out, indent+2);
s = s->GetNext();
} while (s != NULL);
}
else out << ind << " empty." << endl;
return out;
}
bool CAstStatIf::TypeCheck(CToken *t, string *msg) const
{
CAstExpression *cond = GetCondition();
bool result = true;
if (!cond->TypeCheck(t, msg)) return false;
if (cond->GetType() != CTypeManager::Get()->GetBool()) {
if (t != NULL) *t = cond->GetToken();
if (msg != NULL) *msg = "boolean expression expected.";
return false;
}
try {
CAstStatement *ifBody = GetIfBody();
CAstStatement *elseBody = GetElseBody();
while (result && (ifBody != NULL)) {
result = ifBody->TypeCheck(t, msg);
ifBody = ifBody->GetNext();
}
while (result && (elseBody != NULL)) {
result = elseBody->TypeCheck(t, msg);
elseBody = elseBody->GetNext();
}
} catch (...) {
result = false;
}
return result;
}
CTacAddr* CAstStatWhile::ToTac(CCodeBlock *cb, CTacLabel *next)
{
CTacLabel* lcond = cb->CreateLabel("while_cond"); // condition label
CTacLabel* lbody = cb->CreateLabel("while_body"); // body label
cb->AddInstr(lcond); // install condition label
_cond->ToTac(cb, lbody, next);
cb->AddInstr(lbody);
CAstStatement *s = _body;
while(s != NULL) {
CTacLabel *tempnext = cb->CreateLabel();
s->ToTac(cb, tempnext);
cb->AddInstr(tempnext);
s = s->GetNext();
}
cb->AddInstr(new CTacInstr(opGoto, lcond));
return NULL;
}
bool CAstScope::TypeCheck(CToken *t, string *msg) const
{
bool result = true;
try {
CAstStatement *s = _statseq;
while(result && (s != NULL)) { // do TypeCheck for all statements under this scope
result = s->TypeCheck(t, msg);
s = s->GetNext();
}
vector<CAstScope*>::const_iterator it = _children.begin();
while(result && (it != _children.end())) { // do TypeCheck for all scopes under this scope
result = (*it)->TypeCheck(t, msg);
it++;
}
} catch(...) {
result = false;
}
return result;
}
void CAstStatWhile::toDot(ostream &out, int indent) const
{
string ind(indent, ' ');
CAstNode::toDot(out, indent);
_cond->toDot(out, indent);
out << ind << dotID() << "->" << _cond->dotID() << ";" << endl;
if (_body != NULL) {
CAstStatement *s = _body;
if (s != NULL) {
string prev = dotID();
do {
s->toDot(out, indent);
out << ind << prev << " -> " << s->dotID() << " [style=dotted];"
<< endl;
prev = s->dotID();
s = s->GetNext();
} while (s != NULL);
}
}
}
CTacAddr* CAstStatIf::ToTac(CCodeBlock *cb, CTacLabel *next)
{
assert(cb != NULL && next != NULL);
CAstExpression *cond = GetCondition();
CAstStatement *ifBody = GetIfBody();
CAstStatement *elseBody = GetElseBody();
CTacLabel *c_true = cb->CreateLabel("if_true");
CTacLabel *c_false = cb->CreateLabel("if_false");
// starting with translate condition
CTacAddr *tCond = cond->ToTac(cb, c_true, c_false);
if(dynamic_cast<CAstDesignator*>(cond)) { // if cond is a single boolean
cb->AddInstr(new CTacInstr(opEqual, c_true, tCond, new CTacConst(1)));
cb->AddInstr(new CTacInstr(opGoto, c_false));
}
// if_body starts..
cb->AddInstr(c_true);
while(ifBody) {
CTacLabel *if_next = cb->CreateLabel("if_next");
ifBody->ToTac(cb, if_next);
cb->AddInstr(if_next);
ifBody = ifBody->GetNext();
}
cb->AddInstr(new CTacInstr(opGoto, next));
// if else_body exists, else_body starts..
cb->AddInstr(c_false);
if(elseBody) {
while(elseBody) {
CTacLabel *else_next = cb->CreateLabel("else_next");
elseBody->ToTac(cb, else_next);
cb->AddInstr(else_next);
elseBody = elseBody->GetNext();
}
cb->AddInstr(new CTacInstr(opGoto, next));
}
return NULL;
}
CAstStatement* CParser::statSequence(CAstScope *s)
{
//
// stateSequence ::= [ statement { ";" statement } ].
// statement ::= assignment | subroutineCall
// | ifStatement | whileStatement | returnStatement.
//
CAstStatement *head = NULL;
CAstStatement *tail = NULL;
CToken tt = _scanner->Peek();
while (!_abort && tt.GetType() != kEnd && tt.GetType() != kElse) {
CAstStatement *st = NULL;
// stateSequence -> ... statement ...
tt = _scanner->Peek();
switch (tt.GetType()) {
// statement -> assignment | subroutineCall
case tIdent:
{
const CSymbol *sym = s->GetSymbolTable()->FindSymbol(tt.GetValue(), sLocal);
if (!sym) sym = s->GetSymbolTable()->FindSymbol(tt.GetValue(), sGlobal);
if (!sym) SetError(tt, "undeclared variable \"" + tt.GetValue() + "\"");
ESymbolType stype = sym->GetSymbolType();
if (stype == stProcedure) st = subroutineCall(s);
else st = assignment(s);
}
break;
// statement -> ifStatement
case kIf:
st = ifStatement(s);
break;
// statement -> whileStatement
case kWhile:
st = whileStatement(s);
break;
// statement -> returnStatement
case kReturn:
st = returnStatement(s);
break;
default:
SetError(_scanner->Peek(), "statement expected.");
break;
}
assert(st);
if (!head) head = st;
else tail->SetNext(st);
tail = st;
tt = _scanner->Peek();
if (tt.GetType() == kEnd || tt.GetType() == kElse) break;
// stateSequence -> ... ";" ...
Consume(tSemicolon);
}
return head;
}