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//===- RpnEvaluator.cpp ---------------------------------------------------===//
//
// The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "mcld/Script/RpnEvaluator.h"
#include "mcld/LD/LDSymbol.h"
#include "mcld/Script/ExprToken.h"
#include "mcld/Script/Operand.h"
#include "mcld/Script/Operator.h"
#include "mcld/Script/RpnExpr.h"
#include "mcld/Support/MsgHandling.h"
#include "mcld/Module.h"
#include <llvm/Support/Casting.h>
#include <llvm/Support/DataTypes.h>
#include <stack>
#include <cassert>
namespace mcld {
RpnEvaluator::RpnEvaluator(const Module& pModule,
const TargetLDBackend& pBackend)
: m_Module(pModule), m_Backend(pBackend) {
}
bool RpnEvaluator::eval(const RpnExpr& pExpr, uint64_t& pResult) {
std::stack<Operand*> operandStack;
for (RpnExpr::const_iterator it = pExpr.begin(), ie = pExpr.end(); it != ie;
++it) {
switch ((*it)->kind()) {
case ExprToken::OPERATOR: {
Operator* op = llvm::cast<Operator>(*it);
switch (op->arity()) {
case Operator::NULLARY: {
operandStack.push(op->eval(m_Module, m_Backend));
break;
}
case Operator::UNARY: {
Operand* opd = operandStack.top();
operandStack.pop();
op->appendOperand(opd);
operandStack.push(op->eval(m_Module, m_Backend));
break;
}
case Operator::BINARY: {
Operand* opd2 = operandStack.top();
operandStack.pop();
Operand* opd1 = operandStack.top();
operandStack.pop();
op->appendOperand(opd1);
op->appendOperand(opd2);
operandStack.push(op->eval(m_Module, m_Backend));
break;
}
case Operator::TERNARY: {
Operand* opd3 = operandStack.top();
operandStack.pop();
Operand* opd2 = operandStack.top();
operandStack.pop();
Operand* opd1 = operandStack.top();
operandStack.pop();
op->appendOperand(opd1);
op->appendOperand(opd2);
op->appendOperand(opd3);
operandStack.push(op->eval(m_Module, m_Backend));
break;
}
} // end of switch operator arity
break;
}
case ExprToken::OPERAND: {
Operand* opd = llvm::cast<Operand>(*it);
switch (opd->type()) {
case Operand::SYMBOL: {
// It's possible that there are no operators in an expression, so
// we set up symbol operand here.
if (!opd->isDot()) {
SymOperand* sym_opd = llvm::cast<SymOperand>(opd);
const LDSymbol* symbol =
m_Module.getNamePool().findSymbol(sym_opd->name());
if (symbol == NULL) {
fatal(diag::fail_sym_resolution) << __FILE__ << __LINE__
<< "mclinker@googlegroups.com";
}
sym_opd->setValue(symbol->value());
}
operandStack.push(opd);
break;
}
default:
operandStack.push(opd);
break;
} // end of switch operand type
break;
}
} // end of switch
} // end of for
// stack top is result
assert(operandStack.top()->type() == Operand::SYMBOL ||
operandStack.top()->type() == Operand::INTEGER ||
operandStack.top()->type() == Operand::FRAGMENT);
pResult = operandStack.top()->value();
return true;
}
} // namespace mcld