bool ValidateLimitations::validateForLoopCond(TIntermLoop *node,
int indexSymbolId)
{
TIntermNode *cond = node->getCondition();
if (cond == NULL)
{
error(node->getLine(), "Missing condition", "for");
return false;
}
//
// condition has the form:
// loop_index relational_operator constant_expression
//
TIntermBinary *binOp = cond->getAsBinaryNode();
if (binOp == NULL)
{
error(node->getLine(), "Invalid condition", "for");
return false;
}
// Loop index should be to the left of relational operator.
TIntermSymbol *symbol = binOp->getLeft()->getAsSymbolNode();
if (symbol == NULL)
{
error(binOp->getLine(), "Invalid condition", "for");
return false;
}
if (symbol->getId() != indexSymbolId)
{
error(symbol->getLine(),
"Expected loop index", symbol->getSymbol().c_str());
return false;
}
// Relational operator is one of: > >= < <= == or !=.
switch (binOp->getOp())
{
case EOpEqual:
case EOpNotEqual:
case EOpLessThan:
case EOpGreaterThan:
case EOpLessThanEqual:
case EOpGreaterThanEqual:
break;
default:
error(binOp->getLine(),
"Invalid relational operator",
GetOperatorString(binOp->getOp()));
break;
}
// Loop index must be compared with a constant.
if (!isConstExpr(binOp->getRight()))
{
error(binOp->getLine(),
"Loop index cannot be compared with non-constant expression",
symbol->getSymbol().c_str());
return false;
}
return true;
}
int ValidateLimitations::validateForLoopInit(TIntermLoop *node)
{
TIntermNode *init = node->getInit();
if (init == NULL)
{
error(node->getLine(), "Missing init declaration", "for");
return -1;
}
//
// init-declaration has the form:
// type-specifier identifier = constant-expression
//
TIntermAggregate *decl = init->getAsAggregate();
if ((decl == NULL) || (decl->getOp() != EOpDeclaration))
{
error(init->getLine(), "Invalid init declaration", "for");
return -1;
}
// To keep things simple do not allow declaration list.
TIntermSequence &declSeq = decl->getSequence();
if (declSeq.size() != 1)
{
error(decl->getLine(), "Invalid init declaration", "for");
return -1;
}
TIntermBinary *declInit = declSeq[0]->getAsBinaryNode();
if ((declInit == NULL) || (declInit->getOp() != EOpInitialize))
{
error(decl->getLine(), "Invalid init declaration", "for");
return -1;
}
TIntermSymbol *symbol = declInit->getLeft()->getAsSymbolNode();
if (symbol == NULL)
{
error(declInit->getLine(), "Invalid init declaration", "for");
return -1;
}
// The loop index has type int or float.
TBasicType type = symbol->getBasicType();
if ((type != EbtInt) && (type != EbtFloat))
{
error(symbol->getLine(),
"Invalid type for loop index", getBasicString(type));
return -1;
}
// The loop index is initialized with constant expression.
if (!isConstExpr(declInit->getRight()))
{
error(declInit->getLine(),
"Loop index cannot be initialized with non-constant expression",
symbol->getSymbol().c_str());
return -1;
}
return symbol->getId();
}
bool ValidateLimitations::validateForLoopExpr(TIntermLoop *node,
int indexSymbolId)
{
TIntermNode *expr = node->getExpression();
if (expr == NULL)
{
error(node->getLine(), "Missing expression", "for");
return false;
}
// for expression has one of the following forms:
// loop_index++
// loop_index--
// loop_index += constant_expression
// loop_index -= constant_expression
// ++loop_index
// --loop_index
// The last two forms are not specified in the spec, but I am assuming
// its an oversight.
TIntermUnary *unOp = expr->getAsUnaryNode();
TIntermBinary *binOp = unOp ? NULL : expr->getAsBinaryNode();
TOperator op = EOpNull;
TIntermSymbol *symbol = NULL;
if (unOp != NULL)
{
op = unOp->getOp();
symbol = unOp->getOperand()->getAsSymbolNode();
}
else if (binOp != NULL)
{
op = binOp->getOp();
symbol = binOp->getLeft()->getAsSymbolNode();
}
// The operand must be loop index.
if (symbol == NULL)
{
error(expr->getLine(), "Invalid expression", "for");
return false;
}
if (symbol->getId() != indexSymbolId)
{
error(symbol->getLine(),
"Expected loop index", symbol->getSymbol().c_str());
return false;
}
// The operator is one of: ++ -- += -=.
switch (op)
{
case EOpPostIncrement:
case EOpPostDecrement:
case EOpPreIncrement:
case EOpPreDecrement:
ASSERT((unOp != NULL) && (binOp == NULL));
break;
case EOpAddAssign:
case EOpSubAssign:
ASSERT((unOp == NULL) && (binOp != NULL));
break;
default:
error(expr->getLine(), "Invalid operator", GetOperatorString(op));
return false;
}
// Loop index must be incremented/decremented with a constant.
if (binOp != NULL)
{
if (!isConstExpr(binOp->getRight()))
{
error(binOp->getLine(),
"Loop index cannot be modified by non-constant expression",
symbol->getSymbol().c_str());
return false;
}
}
return true;
}